February BATTELLE MEMORIAL INSTITUTE · 2018. 1. 30. · 3 3679 00061 6393 BNWL-1244 UC-41, Health and Safety REMOVAL OF IODINE AND PARTICLES FROM CONTAINMENT ATMOSPHERES BY SPRAYS--

t ' * k,

*" , * 1

- . " - . "... . BATTELLE MEMORIAL INSTITUTE PACIFIC

BATTELkE BOULEVARD, P 0. BOX 999, RlCHL 4. .

3 3679 00061 6393

BNWL-1244

UC-41, Health and Safety

REMOVAL OF I O D I N E AND P A R T I C L E S

FROM C O N T A I N M E N T ATMOSPHERES BY S P R A Y S- -

C O N T A I N M E N T SYSTEMS E X P E R I M E N T

I N T E R I M REPORT

R . K. H i l l i a r d L . F . C o l e m a n C . E . L i n d e r o t h J . D . M c C o r m a c k A . K . P o s t m a

FLkid and Energy Systems Department Physics and Engineering Division

February 1970 )

BATTELLE MEMORIAL INSTITUTE PACIFIC NORTHWEST LABORATORIES

RICHLAND, WASHINGTON 99352

Printed in the United States of America Available from

Clearinghouse for Federal Scientific and Technical Information National Bureau of Standards. U.S. Department of Commerce

Springfield, virginia i2151 Price: Printed Copy $3.00; Microfiche $0.65

REMOVAL OF IODINE AND PARTICLES

FROM CONTAI NMENT A T M O S P H E R E S B Y S P R A Y S - -

CONTAINMENT SYSTEMS EXPERIMENT

INTERIM REPORT

R . K . H i l l i a r d , L . F . Co leman, C . E. L i n d e r o t h , J . D. McCormack , A . K . Pos tma

ABSTRACT

a The e x p e r i m e n t a l d a t a o b t a i n e d i n f i v e s p r a y exper imen t s

i n t h e Containment Systems Experiment (CSE) a r e r e p o r t e d i n 4 A d e t a i l . The per formance of c a u s t i c - b o r a t e s p r a y s i n decontami-

n a t i n g t h e con ta inmen t a tmosphere of e l e m e n t a l i o d i n e , me thy l * i o d i d e , p a r t i c u l a t e i o d i n e , ces ium, and uranium i s d i s c u s s e d

i n t e rms of t h e o r e t i c a l models . Pa ramete r s i n v e s t i g a t e d were

s p r a y f l o w r a t e , s p r a y d r o p s i z e , a tmosphere t e m p e r a t u r e and

p r e s s u r e , and chemica l compos i t ion of t h e s p r a y s o l u t i o n .

Removal r a t e s were i n agreement w i t h p r e d i c t i o n s by mathemat i-

c a l models based on mean s p r a y d rop d i a m e t e r s . Large concen-

t r a t i o n r e d u c t i o n f a c t o r s (>1000) were o b t a i n e d f o r a l l s p e c i e s

e x c e p t me thy l i o d i d e , which was removed o n l y s l o w l y by t h e

c a u s t i c s p r a y s . Based on t h e s e e x p e r i m e n t s , t h e models p r e d i c t

2 - h r t i m e - i n t e g r a t e d dose r e d u c t i o n f a c t o r s a t t r i b u t a b l e t o con-

t i n u o u s s p r a y s i n a l a r g e power r e a c t o r b u i l d i n g r a n g i n g from

1 . 5 f o r me thy l i o d i d e t o 50 f o r e l e m e n t a l i o d i n e , w i t h i n t e r -

m e d i a t e v a l u e s f o r ces ium, uranium, and p a r t i c u l a t e i o d i n e .

i i i

C O N T E N T S

LIST OF FIGURES . . vii LIST OF TABLES . . xi

INTRODUCTION . 1

SUMMARY AND CONCLUSIONS . 3

THEORY OF GAS AND PARTICLE WASHOUT BY SPRAYS . 7

General . 7

Absorption of Airborne Gases by Reactive Liquids . 7

Negligible Back Pressure of Dissolved Gas at Interface . . 12

Liquid Phase Mass Transfer Controlling. . 17

Effect of Recirculation . . 21

Removal of Aerosol Particles . . 22

Gravitational Settling. . 23

Brownian Diffusion. . 24

Inertial Impaction. . 25

Interception . . 25

Diffusiophoresis . . 25

Thermophoresis. . 27

Electrical Attraction . . 27

Effect of Recirculation on Airborne Particle Washout . . 27

Effect of Partial Spray Coverage . . 28

EXPERIMENTAL CONDITIONS . . 31

Experimental Equipment . . 31

Experimental Procedure . . 35

Test Conditions . . 38

Sample Analysis and Data Handling. . 44

RESULTS AND DISCUSSION . . 45

Release to the Containment Atmosphere. . 45

Overall Mass Balances . . 45

Visual Observations of the Containment Atmosphere . . 49

Aerosol and Iodine Forms in the Containment Atmosphere. . 51

Spray Operation . . 52

BNWL- 1244

Spray System Characteristics . . 52

Heat Removal by Sprays. . 54

Variation in Gas Phase Spatial Concentration . . 56

Concentration Variations Within the Main Room . . 56

Concentration Variations Between Compartments . . 65

Removal from Containment Atmospheres by Sprays . . 67

Maypack Data Interpretation . . 67

Concurrent Removal by Natural Processes . . 70

Elemental Iodine . . 72

Particulate-Associated Iodine . . 78

Iodine on Charcoal Paper . . 78

Methyl Iodide . . 92

Total Iodine . .. . . 92

Cesium. . 105 Uranium . . 105

Concentration in Liquid Phases . . 118 Collection in Vessel Sumps. . 118 Concentration in Spray Drops . . 130 Concentration in the Wall Film. . 135 Final Equilibrium . . 140

Particle Size Measurement. . 142 Deposition Coupon Data . . 143 COMPARISON OF THEORY WITH EXPERIMENT . . 149 Elemental Iodine . . 149

Initial Spray Washout Rate. . 149 Equilibrium Gas Phase Concentration . . 157 Dose Reduction Factors. . 160

Methyl Iodide. . 161 Methyl Iodide Reaction Rates . . 162 Removal of Methyl Iodide by Nonreactive Sprays. . 163 Removal of Methyl Iodide by Reactive Sprays . . 166

Aerosol Particles. . 168 ACKNOWLEDGEMENTS . . 173 NOMENCLATURE . . 175 REFERENCES . . 179 APPENDIX: FACILITY DESCRIPTION . . A-1

F I G U R E S

Schematic Diagram of Liquid Flow in the CSE Vessel

Schematic Diagram of Transport Between Sprayed and Unsprayed Regions

Schematic Diagram of Containment Arrangement Used in CSE Spray Tests

Containment Vapor Temperature and Pressure Response to Spray in Run A7

Location of Maypack Clusters in CSE

Typical Buildup of Concentration in Lower Rooms

Concentration of Elemental Iodine in the Main Room, Run A3



Concentration of Elemental Iodine in the Main Room, Run A7 76

Concentration of Elemental Iodine in the Main Room, Run A8 77

Concentration of Particulate Iodine in the Main Room, Run A3 80


Concentration of Particulate Iodine in the Main Room, Run A6 8 2



Concentration in Main Room of Iodine Associated with Charcoal Paper, Run A3 86

Concentration in Main Room of Iodine Associated with Charcoal Paper, Run A4 8 7

Concentration in Main Room of Iodine Associated with Charcoal Paper, Run A6 8 8

Concentration in Main Room of Iodine Associated with Charcoal Paper, Run A7 89

vii

Concentration in Main Room of Iodine Associated with Charcoal Paper, Run A8

Concentration of Methyl Iodide in the Main Room, Run A3





Total Iodine Concentration in the Main Room, Run A3



Total Iodine Conc~ntration in the Main Room, Run A7


Cesium Concentration in the Main Room, Run A3





Uranium Concentration in the Main Room, Run A3


Uranium Concentration in the Main Room, &n A6



Liquid Volumes and Concentrations in Vessel Sumps, Run A3




Liquid Volumes and Concentrations in Vessel Sumps Versus Time--Run A8

BNWL -

Iodine Distribution Versus Time--Run A3

Iodine Distribution Versus Time--Run A7

Cesium Distribution Versus Time--Run A3

Cesium Distribution Versus Time--Run A7

Iodine and Cesium Concentrations in Spray Drops-- Run A3

Iodine and Cesium Concentration in Spray Drops-- Run A4



Iodine and Cesium Concentration in Wall Film, Run A3



Wall Trough Concentration Versus Time--Run A8

Drop Size Distribution for Sprays Used in CSE

Effect of Initial Downward Velocity on Drop Absorption

Comparison of Experimental Initial Washout of Elemental Iodine with Drop Absorption Model

Predicted Particle Collection Efficiency for Falling Drops

Phantom View of CSE Facility

An Exterior View of the Upper Half of the CSE Vessel Before Thermal Insulation Was Installed

Schematic Diagram of CSE Aerosol Sampling System

A View of CSE Maypack Cluster with Cover Removed

-Schematic Diagram of a CSE Maypack Showing Filter and Adsorber Arrangement

Flowsheet of CSE Spray System

T A B L E S

L. 1 Physical Conditions Common to All Spray Experiments 39

- 2 Nozzles Used in CSE Spray Experiments 40 4 - - 3 Atmospheric Conditions in CSE Spray Experiments 41

4 Spray Flow Rates and Solutions Used in CSE r Experiments

5 Timing of Spray Periods

6 Iodine Material Balances - 7 Cesium Material Balances 47

8 Average Distribution of Iodine and Cesium at End t - of Experiment 49

9 Iodine Form at Beginning of First Spray 51

10 Measured Spray Liquid Distribution in CSE Tests 52

11 Heat Removal from Upper Vapor Space by a Spray 56

12 Locations of Maypack Clusters Used in CSE Spray Experiments 57

13 Iodine Concentrations at Various Vessel Locations During First Spray Period - CSE Run A3 60

14 'Iodine Concentrations at Various Vessel Locations During First Spray Period - CSE Run A4 61

15 Iodine Concentrations at Various Vessel Locations During First Spray Period - CSE Run A6 6 2

16 Iodine Concentrations at Various Vessel Locations During First Spray Period - CSE Run A7 63

17 Cesium Concentrations in Vapor Space at Various Vessel Locations During First Spray Period 64

18 Comparison of Concentrations in Sprayed and Nonsprayed Regions Within the Main Room

19 Removal of Elemental Iodine in CSE Spray Tests 79

20 Removal of Particula'e Iodine in CSE Spray Tests 8 5

21 Removal of Iodine Form Associated with Charcoal Paper in CSE Spray Tests 9 1

22 Removal of Methyl Iodide in CSE Spray Tests

23 Removal of Total Iodine in CSE Spray Tests

24 Removal of Cesium in CSE Spray Tests

25 Removal of Uranium in CSE Spray Tests

26 Typical Water Balance--Run A7 120

Comparison of Iodine and Cesium Mass Gained by Liquids with Loss by Gas--Run A4

Equilibrium After Recirculation

Particle Size Analyses - CSE Spray Tests

Iodine Deposition on Various Noncondensing Surfaces

Cesium Deposition on Various Noncondensing Surfaces

Deposition on Vessel Surfaces Inferred from Coupon Data

Comparison of Deposition by Coupon Data with Material Balance Calculations

Observed Washout of Elemental Iodine During First Spray Period

Predicted Washout Constants for CSE Spray Tests

Partition Coefficients for Elemental Iodine

Estimated Reaction Rate Constants of Spray Solutions with Methyl Iodide

Methyl Iodide Washout by Unreactive Water Sprays

Estimated Reaction Rates and Psrtition Coefficients for Thiosulfate Sprays

Methyl Iodide Absorption by Thiosulfate Sprays in CSE

Washout of Cesium Particles by CSE Sprays

Washout of Uranium Oxide Aerosol by CSE Sprays

R E M O V A L O F I O D I N E A N D P A R T I C L E S

FROM C O N T A I N M E N T A T M O S P H E R E S B Y S P R A Y S - -

C O N T A I N M E N T S Y S T E M S E X P E R I M E N T

I N T E R I M R E P O R T

R . K. H i l l i a r d , L . F . Coleman, C . E . L i n d e r o t h , J. D . McCormack, A . K . P o s t m a

I N T R O D U C T I O N

The t r e n d i n t h e n u c l e a r power i n d u s t r y i s f o r more

r e l i a n c e on e n g i n e e r e d s a f e t y f e a t u r e s t o meet t h e l i c e n s i n g

r e q u i r e m e n t s s e t f o r t h by t h e AEC r e a c t o r s i t e c r i t e r i a . ( 1 , 2 )

The con ta inmen t s p r a y sys t em, a common s a f e t y f e a t u r e i n many

second g e n e r a t i o n n u c l e a r power r e a c t o r s , u s u a l l y i s d e s i g n e d

f o r t h e d u a l pu rposes of p r e s s u r e s u p p r e s s i o n and f i s s i o n

p r o d u c t removal . To p e r m i t e v a l u a t i o n of t h e l a t t e r f u n c t i o n ,

each s p e c i f i c r e a c t o r s p r a y sys tem must be c o n s i d e r e d on t h e

b a s i s of fundamenta l knowledge of t h e p r o c e s s e s i n v o l v e d

coup led w i t h a d e q u a t e d e m o n s t r a t i o n t e s t s under c o n d i t i o n s

s i m i l a r t o t h o s e e x p e c t e d i n t h e d e s i g n b a s i s a c c i d e n t (DBA).

An e x t e n s i v e e x p e r i m e n t a l program t o f u r n i s h t h i s i n f o r m a t i o n

i s sponsored by t h e USAEC D i v i s i o n of Reac to r Development and

Technology. (3) Work r e p o r t e d i n t h i s document i s a p a r t of

t h i s program.

Because i o d i n e is u s u a l l y t h e c r i t i c a l f i s s i o n p r o d u c t i n

r e a c t o r s i t i n g c a l c u l a t i o n s , much s t u d y h a s been conducted on

i t s b e h a v i o r . G r i f f i t h s ( 4 ) a p p l i e d s t a n d a r d e n g i n e e r i n g c o r r e -

l a t i o n s t o d e v e l o p e q u a t i o n s f o r p r e d i c t i n g t h e r a t e of removal

of i o d i n e from r e a c t o r b u i l d i n g a tmospheres by wa te r and

chemica l s p r a y s . G r i f f i t h s ' e q u a t i o n s , a l t h o u g h l a r g e l y s u b -

s t a n t i a t e d by s m a l l s c a l e e x p e r i m e n t s , c a n n o t be a p p l i e d w i t h

comple te c o n f i d e n c e t o l a r g e power r e a c t o r sys t ems u n t i l l a r g e -

s c a l e e x p e r i m e n t s e x p l a i n i n g t h e e f f e c t s of c e r t a i n unknown

f a c t o r s r e l a t e d t o s i z e and geometry can b e per formed.

The Containment Systems Experiment (CSE) has many features

of an actual power reactor containment building. Its 3 30,000 ft shell, painted and with many typical penetrations,

has several smaller compartments which can affect concentra-

tion gradients. Its size permits spray experiments, with most

important parameters appearing in the mathematical models, to

be conducted either at full scale or within a factor of four

of full scale. Aspects best adapted to study by large-scale

experiments include the effect of natural deposition on sur-

faces, desorption, wall impingement by spray drops, intercom-

partment transfer, mixing in the vapor space, partial spray

coverage, drop coalescence, and approach to drop saturation.

All of these effects have been studied in the CSE experiments.

Because the information derived from the CSE spray experi-

ments is urgently needed for licensing purposes, this interim

report is being issued before the entire CSE experimental pro-

gram has been completed. The information presented here is in

final form for the five experiments reported, and is considered

to provide an adequate basis for several important conclusions.

Subsequent experiments were not fully evaluated at the time

this report was written, but preliminary analyses show the

later experiments to be in agreement with the conclusions made

in this report.

SUMMARY A N D C O N C L U S I O N S

The r e s u l t s of f i v e CSE expe r imen t s (Runs A3, A4, A6, A 7 ,

and A 8 ) employing aqueous s p r a y s a r e r e p o r t e d i n d e t a i l . The

pr ime o b j e c t i v e of t h e s e t e s t s was t o v e r i f y t h e o r e t i c a l models

c a p a b l e o f p r e d i c t i n g t h e removal by s p r a y s of f i s s i o n p r o d u c t s

from t h e a tmospheres of l a r g e power r e a c t o r con ta inmen t v e s s e l s

under p o s t a c c i d e n t c o n d i t i o n s . T h e r e f o r e , t h e s e expe r imen t s

were per formed i n a manner d e s i g n e d t o o b t a i n i n f o r m a t i o n

needed f o r v e r i f i c a t i o n o f ma themat i ca l models . L a t e r r u n s ,

t o be r e p o r t e d s e p a r a t e l y , were performed i n a manner more

c l o s e l y r e p r e s e n t i n g s p r a y sys t em per formance under a c c i d e n t

c o n d i t i o n s .

A f t e r t h e d e s i r e d a t m o s p h e r i c c o n d i t i o n s were e s t a b l i s h e d

i n t h e v e s s e l , f i s s i o n p r o d u c t s i m u l a n t s were i n j e c t e d i n

e s s e n t i a l l y an i n s t a n t a n e o u s manner. The i n i t i a l e l e m e n t a l

i o d i n e c o n c e n t r a t i o n was i n t h e maximum r a n g e expec ted f o r an 3 a c c i d e n t t o a l a r g e PWR ( ~ 1 0 0 mg/m ) . P a r t i c u l a t e c o n c e n t r a -

t i o n s were a f a c t o r of 1 0 l ower . The s p r a y s were t h e n o p e r a t e d

p e r i o d i c a l l y , w i t h e x t e n s i v e sampl ing d u r i n g and between s p r a y

p e r i o d s t o d e t e r m i n e t h e e f f e c t of each s p r a y p e r i o d on t h e

c o n c e n t r a t i o n s of e a c h f i s s i o n p r o d u c t s p e c i e s . A f i n a l s p r a y

r e c i r c u l a t i o n p e r i o d was i n c l u d e d .

A major pa ramete r was changed i n e a c h exper imen t . Two

v a l u e s f o r each o f two p a r a m e t e r s a p p e a r i n g i n t h e t h e o r e t i c a l 3 models were u s e d . These were s p r a y f l u x (0.004 and 0.018 f t /

h r p e r f t 3 of c o n t a i n e d g a s s p a c e ) and s p r a y d r o p s i z e ( 7 7 0 and

1210 p M M D ) . I n a d d i t i o n , two p a r a m e t e r s i n d i r e c t l y i n f l u e n c i n g

s p r a y per formance were i n v e s t i g a t e d . These were t h e con ta inmen t

a t m o s p h e r i c c o n d i t i o n (room a i r a t b a r o m e t r i c p r e s s u r e o r s team-

a i r a t 250 O F , 48 p s i a ) and t h e chemica l compos i t ion of t h e

s p r a y s o l u t i o n ( b a s e - b o r a t e , pH 9 . 5 o r b o r i c a c i d , pH 5 ) . The

l a t t e r two a f f e c t e d e i t h e r t h e mass t r a n s f e r c o e f f i c i e n t , t h e

d rop f a l l v e l o c i t y , chemica l r e a c t i o n r a t e s , c o l l e c t i o n

BNWL- 1244

efficiency for particles, or the iodine equilibrium gas-liquid

distribution coefficient, all of which appear in one or more

versions of the mathematical models. In two experiments,

sodium thiosulfate was added to determine its effect on removal

of methyl iodide. The only major parameters not varied were

the drop fall height (38.5 ft for all tests) and the gas to

liquid volume ratio (~80).

Time-dependent measurements are reported for mass concen-

trations in the vapor spaces and for liquid concentrations in

the pools, wall film, and in spray drops during flight.

Fission product species studied were elemental iodine, methyl

iodide, particulate iodine, cesium, and uranium.

The following conclusions are based on evaluation of the

experimental data presented in this report.

Good agreement ('20% for all tests) was obtained between

experimental values of initial removal rate for elemental

iodine and predictions based on gas phase limited transfer

and on mean drop size. The measured concentration half

lives of 0.6 to 2.0 min are in the range expected for

large power reactor systems.

The gas phase limited rate for elemental iodine lasted

only until the airborne concentration was reduced to

about 0.01 of the initial value, after which the concen-

tration decreased more slowly. A quasi-equilibrium

attained in all tests gave an overall concentration

reduction factor of about 1000 after one day.

Based on these experiments, the 2-hr time-integrated dose

reduction factor (DRF) for a large PWR is estimated to be about 50 for elemental iodine. At longer times, the DRF

would be appreciably greater.

Removal of methyl iodide by hot base-borate sprays was too

slow for accurate measurement in these experiments

( t l / ~ > 500 min). 4

8 Removal of methyl i o d i d e by h o t b a s e - b o r a t e - s o d i u m t h i o -

s u l f a t e s p r a y s a g r e e d w e l l w i t h p r e d i c t i o n s by a model

based on a chemica l r e a c t i o n r a t e l i m i t i n g p r o c e s s . The

removal r a t e i s h i g h l y t e m p e r a t u r e dependent and t h e w a l l

f i l m i s more e f f e c t i v e t h a n t h e d r o p s . A low 2- h r DRF

( ~ 1 . 5 ) would be expec ted i n a l a r g e PWR. The 24-hr DRF

f o r methyl i o d i d e would be a b o u t 8 f o r a con ta inmen t

a tmosphere assumed t o remain a t 240 O F .

8 Removal of a e r o s o l p a r t i c l e s (ces ium, uranium, and p a r -

t i c u l a t e i o d i n e ) was s i g n i f i c a n t l y h i g h e r t h a n p r e d i c t e d

by a model u s i n g p a r t i c l e s i z e d a t a o b t a i n e d d u r i n g t h e

t e s t s . Agreement c o u l d be o b t a i n e d f o r mass mean d i a m e t e r s

of 2-4 v MMD, i n s t e a d of t h e 0 .25-2 v r a n g e measured by a

c a s c a d e i m p a c t o r . The measured s i z e i s s u s p e c t e d of b i a s

toward low v a l u e s due t o e v a p o r a t i o n of w a t e r from t h e

p a r t i c l e s d u r i n g p a s s a g e th rough t h e s i z i n g a p p a r a t u s .

8 The o v e r a l l c o n c e n t r a t i o n r e d u c t i o n f a c t o r f o r cesium and

p a r t i c u l a t e i o d i n e was abou t 1000. For uranium i t was

~ 5 0 0 . Assuming t h e p a r t i c l e s i z e s i n t h e s e f i v e e x p e r i -

ments t o be t y p i c a l of t h o s e accompanying a LOCA f o r a

l a r g e power r e a c t o r , t h e 2 - h r DRF f o r cesium would be

a b o u t 20 and , f o r uranium, abou t 10 .

The c o n c e n t r a t i o n s of a l l f i s s i o n p r o d u c t s p e c i e s were

e s s e n t i a l l y un i fo rm th roughou t t h e main con ta inmen t vapor

s p a c e r e g a r d l e s s of removal r a t e s o r f r a c t i o n of g a s s p a c e

s p r a y e d .

8 The e f f e c t of s p r a y d r o p s i z e on i n i t i a l washout r a t e f o r

e l e m e n t a l i o d i n e was a b o u t a s p r e d i c t e d , w i t h s m a l l e r

d r o p s g i v i n g more r a p i d removal . I n two t e s t s w i t h o t h e r

f a c t o r s e q u a l , 1210 p MMD d rops gave a 2 . 1 min i n i t i a l

c o n c e n t r a t i o n h a l f l i f e , w h i l e 770 v MMD d r o p s gave

0 .64 min. Based on t h e e q u i l i b r i u m r e a c h e d a f t e r

C = 0 .01 C a s observed i n t h e s e e x p e r i m e n t s , t h e g go'

e q u i v a l e n t 2 - h r DRF f o r 1210 d r o p s would be 30 w h i l e ,

f o r 770 p d r o p s , i t would be 57.

The i n i t i a l washout r a t e of a l l f i s s i o n p r o d u c t m a t e r i a l s

was d i r e c t l y p r o p o r t i o n a l t o s p r a y r a t e . However, t h e

maximum s p r a y f l u x used was somewhat low compared t o t h a t

p l anned f o r some r e c e n t l y announced p l a n t s .

A b o r i c a c i d s p r a y , pH 5 , was n e a r l y a s e f f e c t i v e a s s p r a y s . c o n t a i n i n g sodium hydrox ide a t a pH of 9 . 5 . The low pH

s o l u t i o n ' s e f f i c i e n c y f o r removing e l e m e n t a l i o d i n e i n d i - . v

c a t e s t h a t a f a s t r e a c t i o n o t h e r t h a n h y d r o l y s i s was

i n v o l v e d .

About 40% of t h e e l e m e n t a l i o d i n e i n j e c t e d was r e t a i n e d

by t h e p h e n o l i c p a i n t and c o u l d n o t be removed by p o s t -

t e s t s t eaming and s p r a y i n g . Most of t h e d e p o s i t i o n

o c c u r r e d d u r i n g t h e s h o r t p e r i o d a f t e r r e l e a s e b u t b e f o r e

s p r a y s were s t a r t e d . E s s e n t i a l l y no cesium was r e t a i n e d

on t h e p a i n t .

T H E O R Y OF G A S A N D P A R T I C L E WASHOUT BY S P R A Y S

G E N E R A L

The removal of airborne fission products by sprays within

containment systems occurs at surfaces within the chamber.

The development of the capability for predicting fission prod-

uct removal under wide ranges of conditions can be realized

only if the mechanisms causing surface deposition are under-

stood. The theory presented here is intended to serve as a

framework for interpreting experimental measurements of spray

washout obtained in the Containment Systems Experiment. For

more detailed theoretical developments, the reader is referred

to the references cited.

A B S O R P T I O N OF A I R B O R N E G A S E S BY R E A C T I V E L I Q U I D S

In gas absorption, solute gas diffuses from the bulk of

the gas to the surface of the liquid. The rate of this trans-

port is governed by the magnitudes of the concentration gradient

and the diffusion coefficient (laminar and turbulent) transport-

ing the solute to the absorbing surface. At the gas-liquid

interface, the solute dissolves in the liquid. Interfacial

dissolution is a very rapid process under ordinary conditions

and, for this reason, surface saturation exists:

where Cli = solute gas concentration on liquid side of interface,

C = solute gas concentration on gas side of interface, g i

He = gas-liquid partition coefficient.

The gas-liquid partition coefficient is the equilibrium constant

for dissolution of the solute. For example, the gas-liquid par-

tition coefficient for elemental iodine is the equilibrium con-

stant for the reaction:

with

The brackets are used here to denote concentrations.

For some systems, the dissolved species may undergo a

very rapid reaction within the liquid to form a nonvolatile

species. Using I2 as an example, this may be indicated as

(very rapid equilibrium).

If this reaction is very fast compared to the absorption pro-

cess, then an effective partition coefficient can be used to

relate the interfacial gas phase composition to the total I2

in solution. From Equations (2) and (3), we can define

where

H = effective partition coefficient,

['Z(X) + ['~(reacted) ] = total concentration of I2 in liquid,

K1 = equilibrium constant for

unreacted species,

K2 = equilibrium constant for instan-

taneous reaction.

In this report, we will use H as defined by Equation (4), and will include very fast reactions occurring in the liquid.

Relatively slow chemical reactions cannot be handled in this

way and their influence must be treated as a kinetic problem.

Since the extent of chemical reactions may be influenced by

the solute gas concentration and impurities in solution, the

magnitude of H as defined by Equation (4) cannot be expected

to be constant at low concentrations. The definition of H in

terms of unreacted species, as in Equation (2) is consistent

with Henry's Law and, hence, the partition coefficient for the

unreacted species would be expected to remain constant at low

concentrations.

The solute gas dissolved at the surface of the liquid will

diffuse away from the interface by laminar and turbulent pro-

cesses. If a chemical reaction occurs within the liquid, the

absorbed substance will be destroyed at a rate depending on its

concentration and reaction rate. Destruction of the solute

species will enhance the absorption by increasing the magnitude

of the concentration gradient at the gas-liquid interface.

Mass transfer coefficients governing the absorption rate

may be defined by the flux equations in terms of the film

theory. ( 5 )

Flux = mols transferred - (area) (time) - kg (Cgb - C gl . ) = kQ (CQi - Cab)

( 5 ) where

k = gas phase mass transfer coefficient, g

kk = liquid phase mass transfer coefficient,

C = solute concentration in bulk of gas, g b

CQb = solute concentration in bulk of liquid.

The use of film coefficients as defined in Equation (5) is

physically consistent only with systems in which each phase is

well mixed in the bulk. on natural transport

of fission products in containment vessels indicate that the

g a s phase would b e w e l l mixed beyond a t h i n boundary l a y e r .

Sprays would induce c o n s i d e r a b l e mixing and , i n t h e models

a p p l i e d h e r e , t h e b u l k g a s phase w i t h i n a s i n g l e compartment

was assumed t o be w e l l mixed. The d e g r e e of mixing i n t h e

l i q u i d p h a s e i s l e s s c e r t a i n . Numerical l i m i t s on kk v a l u e s

may be o b t a i n e d by assuming s t a g n a n t , o r w e l l mixed l i q u i d

p h a s e s . A c t u a l v a l u e s of k Q depend s t r o n g l y on t h e d e g r e e o f

mix ing . -

The a i r b o r n e c o n c e n t r a t i o n of a f i s s i o n p r o d u c t a e r o s o l

o r g a s may be r e l a t e d t o t h e f l o w p a r a m e t e r s of a con ta inmen t q w

v e s s e l by making a m a t e r i a l b a l a n c e on t h e g a s c o n t a i n e d w i t h i n

t h e v e s s e l . A s c h e m a t i c d iagram of t h e l i q u i d f l o w i n t h e CSE

con ta inmen t v e s s e l i s shown i n F i g u r e 1. S i n c e t h e r e a r e t h r e e

i n t e r c o n n e c t e d volumes, a m a t e r i a l b a l a n c e a l l o w i n g f o r t r a n s f e r

between rooms s h o u l d be made on each room. For t h e main con-

t a inmen t volume, t h e m a t e r i a l b a l a n c e i n p u t t e rms f o r a s i n g l e

component a r e :

i n p u t r a t e = G + (C 82 - Cg)B12

where

G = g e n e r a t i o n r a t e of component w i t h i n main c o n t a i n -

ment volume, C = g a s p h a s e c o n c e n t r a t i o n i n midd le room,

82 C = g a s phase c o n c e n t r a t i o n i n main con ta inmen t volume,

g B I Z = exchange c o e f f i c i e n t f o r i n t e r - r o o m t r a n s p o r t .

The o u t p u t r a t e t e rms a r e

o u t p u t r a t e = [ k ( C - g g C g i ) A 1 d r o p s , w a l l f i l m + R~

( 7 )

where

k = g a s p h a s e mass t r a n s f e r c o e f f i c i e n t , g A = i n t e r f a c i a l a r e a f o r mass t r a n s f e r ,

RG = r a t e of g a s phase r e a c t i o n .

FIGURE 1. Schematic Diagram of Liquid Flow in the CSE Vessel

The accumulation term is

d accumulation rate = (V Cg)

where

V = volume of the main containment vessel.

From mass conservation, Equations (6), ( 7 ) , and (8) give

GI + (Cg2 - Cg)B12 = [kg(Cg - Cgi)A1drops, wall film + R~

An equation similar to (9) is required for each of the 3 rooms

within the containment vessel for each fission product com-

ponent. Similarly, material balances on the liquid phase would

be required to permit evaluation of Cgi. Simultaneous solution

of the material balance equations would give the time-

concentration history. Solution of material balance equations

can be realized only after the mass transfer coefficients,

interfacial areas, reaction rates, generation rates, and inter-

room transport coefficient are known as functions of the basic

system parameters. For special cases, the form of the material

balance equations may be simplified, and several of these situ-

ations will be briefly noted.

Negligible Back Pressure of Dissolved Gas at Interface

At the beginning of a spray period, the concentration of

the solute gas in the liquid phases is zero. For a reactive

gas such as elemental iodine, dissolution is accompanied by

rapid chemical reactions which enhances its solubility as indi-

cated by Equation (4). If the equilibrium of the chemical

reaction, Equation ( 3 ) , lies far enough to the right, the gas

'~i concentration at the interface, - H , would be very small compared to C in the bulk and, hence, could be neglected. The

g

inter-room transport would be expected to be relatively small

compared to the spray washout rate at the beginning of a spray

period and, hence, the initial spray washout rate would not be

greatly influenced by inter-room transport. For a puff release

of elemental iodine under conditions where no appreciable

reversible sink-sources are present, the generation rate may

be taken as zero. This assumption is not necessarily valid

even at the beginning of a spray period inasmuch as appreci-

able desorption of iodine from fog drops has been noted on

occasion. For these assumptions, and neglecting gas phase

reactions, the material balance equation gives, for constant

conditions, a washout half-time of

or t - - 1 1 1/2 1 +-

tl/2 (drops) tl/2(wall film)

The gas phase transfer coefficient for falling drops may be

estimated from an empirical equation proposed by Frossling, (9

and modified by Ranz and Marshall (lo) as follows:

where

d = drop diameter,

D = gas phase diffusivity of solute gas,

Re = Reynolds number of falling drop,

Sc = Schmidt number.

This equation may be applied to a spray of known drop size dis-

tribution. The interfacial area for drops of diameter d is

6F te A = -a- (121

where

A = s u r f a c e a r e a of d r o p s ,

F = v o l u m e t r i c g e n e r a t i o n r a t e of d r o p s of s i z e d ,

te = exposure t ime i n chamber f o r a drop of s i z e d .

The a v e r a g e d r o p exposure t ime f o r a v e s s e l i n which t h e r e a r e

d i f f e r e n t f a l l h e i g h t s i s

where

Fi = volume f l o w r a t e of s p r a y f o r te = tei,

F = t o t a l volume f l o w r a t e of s p r a y .

For a p a r t i c u l a r d r o p f a l l h e i g h t , h i , t h e exposure t ime may be

c a l c u l a t e d by assuming t e r m i n a l v e l o c i t y f o r t h e whole t r a j e c -

t o r y a s

where

v = t e r m i n a l s e t t i n g v e l o c i t y , and g

hi = f a l l h e i g h t .

Using Equa t ions (11) , ( 1 2 ) , ( 1 3 ) , and ( 1 4 ) , t h e washout r a t e

c o n s t a n t f o r f a l l i n g d r o p s of s i z e d i s

t e (2 + 0 . 6 Re 0 . 5 sc0.33) -

(kgA) d r o p s -

d 2

T h e o r e t i c a l l y , i t would be b e t t e r t o e v a l u a t e t h e p r o d u c t

te (2 + 0 . 6 Re S C O * ~ ~ ) a s a f u n c t i o n of d i s t a n c e from t h e

n o z z l e . A l s o , t h e washout r a t e f o r t h e whole s p r a y c o u l d b e s t

be o b t a i n e d by i n t e g r a t i n g Equa t ion (15) ove r t h e whole d r o p

s i z e spec t rum. Based on a v e r a g e v a l u e s of t h e p a r a m e t e r s shown

i n E q u a t i o n ( 1 5 ) , t h e r a t e of c o n c e n t r a t i o n d e c r e a s e a s a

r e s u l t o f d rop a b s o r p t i o n , n e g l e c t i n g s o u r c e te rms i s :

C ( 6 k F h t ) - - C g - exp -

go -+in-

g

where h i s t h e a v e r a g e f a l l h e i g h t , de t e rmined by w e i g h t i n g

each f a l l h e i g h t w i t h t h e f l o w r a t e f o r t h a t f a l l h e i g h t .

The t r a n s f e r c o e f f i c i e n t t o w e t t e d w a l l s u r f a c e s i s l e s s

amenable t o c a l c u l a t i o n t h a n t r a n s f e r t o d r o p s . The magni tude

of t h e g a s p h a s e mass t r a n s f e r c o e f f i c i e n t f o r t h e w e t t e d w a l l

w i l l depend on t h e f l o w c o n d i t i o n s and mixing w i t h i n t h e g a s

phase boundary l a y e r . During t h e f i r s t s p r a y p e r i o d , g a s phase

f l o w a l o n g t h e w a l l w i l l be induced by a t h e r m a l g r a d i e n t between

t h e w a l l and t h e b u l k g a s . P r i o r t o i n i t i a t i o n of s p r a y s , t h e

w a l l i s c o o l e r t h a n t h e b u l k g a s which c a u s e s a n a t u r a l convec-

t i o n . f l o w down t h e w a l l . Spray l i q u i d i n t r o d u c e d may be s u b -

s t a n t i a l l y c o o l e r t h a n t h e con ta inmen t t e m p e r a t u r e and , h e n c e ,

t h e g a s i s r a p i d l y c o o l e d t o a t e m p e r a t u r e below t h e w a l l tem-

p e r a t u r e . T h i s t e m p e r a t u r e change would c a u s e a n a t u r a l con-

v e c t i o n f l o w up t h e w a l l . The n a t u r a l c o n v e c t i o n c u r r e n t would

be i n f l u e n c e d by t h e l i q u i d f i l m f l o w i n g down t h e w a l l and by

t h e f a l l i n g s p r a y d r o p s . The i n f l u e n c e of t h e s e two f a c t o r s

w i l l be n e g l e c t e d i n p r e d i c t i n g t h e w a l l f i l m a b s o r p t i o n .

I n t h e absence of s p r a y , t h e mass t r a n s p o r t t o a v e r t i c a l

w a l l may be e s t i m a t e d from a h e a t t r a n s f e r a n a l o g y . Knudsen

and ~ i l l i a r d ( ~ ) have shown t h a t , f o r l a r g e chambers , t h e w a l l

d e p o s i t i o n of i o d i n e vapor may be s a t i s f a c t o r i l y p r e d i c t e d from

a h e a t t r a n s f e r c o r r e l a t i o n o b t a i n e d e m p i r i c a l l y f o r no conden-

s a t i o n . For n e g l i g i b l e s u r f a c e c o n c e n t r a t i o n , t h e mass f l u x is

mass f l u x = k C + k C = (kgCg)wall f i l m s g c g

where

kc = natural convection mass transfer coefficient,

k = mass transfer coefficient due to condensing steam s (sweep effect) .

The heat transfer correlation for turbulent flow may be used to

obtain kc by substituting the Schmidt number for the Prandtl

number :

kcL - - - 0.13 (Gr Sc) 1 / 3 D

where

L = length of vertical surface,

Gr = Grashov number,

Sc = Schmidt number.

The value of ks is equal to the steam sweep velocity:

where

n = mass flux of steam toward wall, S

R = gas constant,

T = absolute temperature in gas film,

P = total pressure in vessel.

The Grashov number must be obtained from thermal hydraulic cal-

culations, or from actual temperature measurements. During the

initial spraying period, water would evaporate from the wall

giving a negative nS and, consequently, a negative ks.

It should be noted that the mass transfer correction due

to the condensing steam flux indicated in Equations (17) and

(19) is not rigorous. Theoretically, the change in the boundary

layer flow should be accounted for as a result of this steam

f l u x , (11) However, s i n c e t h e " c o r r e c t f' i n f l u e n c e of t h e con-

d e n s a t i o n on t h e t u r b u l e n t boundary l a y e r i s n o t p r e c i s e l y

known, and s i n c e t h e c o r r e c t i o n i s r e l a t i v e l y s m a l l , l i t t l e

e r r o r w i l l be i n t r o d u c e d by t h e u s e of t h e c o r r e c t i o n i n d i c a t e d

i n E q u a t i o n s (17 and ( 1 9 ) . Using Equa t ions (15) and ( 1 7 ) , a

washout h a l f - t i m e may be c a l c u l a t e d f o r t h e c a s e of n e g l i g i b l e

i n t e r f a c i a l c o n c e n t r a t i o n . T h i s c a s e would be e x p e c t e d t o

app ly t o i n i t i a l a b s o r p t i o n o f e lemental . i o d i n e . G r i f f i t h s , (4)

i n p r e s e n t i n g c a l c u l a t i o n s f o r t h i s c a s e , n e g l e c t s w a l l f i l m

a b s o r p t i o n and assumes a c o n s t a n t drop f a l l h e i g h t and t h a t

t h e d rops f a l l a t t e r m i n a l v e l o c i t y . P a r s l y h a s c a l c u l a t e d

washout r a t e s a c c o u n t i n g f o r d rops e n t e r i n g a t a v e l o c i t y

h i g h e r t h a n t e r m i n a l v e l o c i t y .

L i a u i d Phase Mass T r a n s f e r C o n t r o l l i n g

A t t h e o p p o s i t e end of t h e s c a l e from Case I i s a b s o r p t i o n

c o n t r o l l e d e n t i r e l y by l i q u i d phase r e s i s t a n c e . L i q u i d phase

r e s i s t a n c e would b e e x p e c t e d t o c o n t r o l t h e a b s o r p t i o n of

s l i g h t l y s o l u b l e g a s e s such a s methyl i o d i d e . For g a s e s obey-

i n g H e n r y ' s Law, t h e o v e r a l l r e s i s t a n c e t o mass t r a n s f e r may

be e x p r e s s e d a s

where

K = o v e r a l l mass t r a n s f e r c o e f f i c i e n t , g

k = g a s p h a s e mass t r a n s f e r c o e f f i c i e n t , g

kg = l i q u i d phase mass t r a n s f e r c o e f f i c i e n t , and

H = g a s - l i q u i d e q u i l i b r i u m p a r t i t i o n c o e f f i c i e n t .

i s l a r g e L i q u i d p h a s e r e s i s t a n c e w i l l be c o n t r o l l i n g i f - H k ~

compared t o G e n e r a l l y , k g v a l u e s a r e s m a l l e r t h a n k kn' g 6

v a l u e s s o t h a t l i q u i d phase r e s i s t a n c e i s i m p o r t a n t u n l e s s

H i s l a r g e compared t o u n i t y .

The numer ica l v a l u e of t h e l i q u i d phase mass t r a n s f e r *. .-

c o e f f i c i e n t depends on t h e r a t e and e x t e n t of chemica l r e a c t i o n s

which d e s t r o y t h e s o l u t e , and on t h e r a p i d i t y of mixing i n t h e

l i q u i d p h a s e . I n t h e f o l l o w i n g p a r a g r a p h , t h e c a l c u l a t i o n of - . 4

a b s o r p t i o n r a t e s f o r f a l l i n g d r o p s and w a l l f i l m s a l l o w s f o r

f i r s t o r d e r chemica l r e a c t i o n s f o r s e v e r a l l i m i t i n g c a s e s of

mixing .

For a s t a g n a n t f a l l i n g d r o p , t h e a b s o r p t i o n i n t ime te i s

g i v e n by Danckwerts (13) as

2 2 2 2 - exp (k + y ) ~ ] } / ( k a 2 + IT 1 -

where

Q = amount absorbed i n t ime te,

DQ = l i q u i d phase d i f f u s i v i t y ,

a = drop r a d i u s ,

k = f i r s t o r d e r r e a c t i o n r a t e c o n s t a n t ,

te = drop exposure t ime .

Equa t ion (21) would be e x p e c t e d t o y i e l d t h e lower l i m i t

of a b s o r p t i o n a s o n l y d i f f u s i o n a l t r a n s p o r t i s assumed. An

upper l i m i t t o a b s o r p t i o n may be e s t i m a t e d by assuming t h e d r o p

t o be p e r f e c t l y mixed a t a l l t i m e s . The a b s o r p t i o n e q u a t i o n

f o r a p e r f e c t l y mixed d rop i s :

Unfortunately, data are not available to permit adequate

assessment of the mixing effect. Studies on larger

drops (14,15916,17) have shown that circulation can occur,

but small amounts of surface active agents can effectively

inhibit circulation. A comparison between absorption rates calculated from Equations (21) and (22) has been presented. (18)

Transfer rates may be calculated from the penetration

theory type models, or from laminar flow theory for liquid

phase controlled wall film absorption. The differential equa-

tion describing absorption into a smooth laminar film is

ac - -(;)'I 3-z a'c - k,

max - D a 7 ax

where

u = velocity at the gas-liquid interface, max

x = distance from surface of film,

6 = thickness of film,

z = distance measured along film,

k = first order reaction rate constant.

For short laminar films, the solute does not have time to

penetrate far into the film and, hence, the absorption takes

place as though the film were infinite in thickness. The

differential equation for absorption in such films may be

obtained from Equation (23) by setting x = 0 . This is the

penetration theory approximation, and the mathematical solu-

tion is given by Danckwerts. (I9) ~ o s t experimental laminar

flow data obtained for short wetted wall columns agree reason-

ably with this penetration theory solution.

For the long films encountered in containment vessels,

laminar flow calculations indicate that the solute may diffuse

all the way through the film. A lower limit to absorption in ac thin films, estimated by solving Equation (23) for = 0, gives

where

= 'ki tanh ( / I T 6)

dq = absorption rate per unit area. aT

The film thickness, 6, used in Equation (24), may be estimated

from laminar flow theory and experimental measurements of the

wall flow rate.

Turbulence, waves, and rivulet formation will cause mixing . .- in actual films. An upper limit to film absorption may be

estimated by considering the film to be perfectly mixed. For

this case, the total film absorption rate for the whole vessel +

would be

Absorption Rate = k CQi VWF + Cei LF

where

VWF = volume of liquid held up on walls as film,

LF = flow rate of liquid film.

In this analysis of wall film absorption, we have neglected

reaction and dissolution of methyl iodide b'y the paint or sur-

face of the wall. Appreciable transfer into the solid wall

would enhance film absorption. Considerable effort has been

devoted to developing paint additives capable of reacting with

methyl iodide. (20) If these were incorporated, an accounting

of the transfer rate from the liquid film to the wall would be

required. An extensive review of absorption and fluid dynamics

of thin films has been presented by Fulford. (21)

In addition to vertical wall surfaces, liquid pools formed

in the bottom of containment vessels represent a region of

additional absorption. Absorption in this volume may be sig-

nificant if a chemical reaction destroys the dissolved gas.

R e a l i s t i c c a l c u l a t i o n of t h e a b s o r p t i o n r a t e i n t o t h e p o o l

s u r f a c e i s p o s s i b l e o n l y i f s u r f a c e renewal r a t e s a r e known.

Upper and lower l i m i t s based on a s t a g n a n t o r a w e l l mixed.

p o o l may be computed.

E f f e c t of R e c i r c u l a t i o n

I n r e a c t o r con ta inmen t s y s t e m s , t h e s p r a y l i q u i d i n t r o -

duced t o c o o l t h e p o s t a c c i d e n t a tmosphere and t o t r a p f i s s i o n

p r o d u c t s w i l l be c o o l e d by h e a t exchange and r e c i r c u l a t e d

th rough t h e s p r a y n o z z l e s . Thus, a f t e r an i n i t i a l p e r i o d of

f r e s h s p r a y , t h e s p r a y l i q u i d e n t e r i n g t h e chamber w i t h a non-

z e r o s o l u t e c o n c e n t r a t i o n w i l l d e c r e a s e t h e c o n c e n t r a t i o n d r i v

i n g f o r c e and s low t h e r a . t e of a b s o r p t i o n . The r a t e of d e c r e a s e

i n g a s phase c o n c e n t r a t i o n depends on t h e way i n which t h e

l i q u i d is mixed w i t h i n t h e chamber, and on t h e r a t e and e x t e n t

of chemica l r e a c t i o n s o c c u r r i n g w i t h i n t h e chamber.

One c a s e amenable t o s i m p l e c a l c u l a t i o n i s based on t h e

a s sumpt ions t h a t (1) Henry ' s Law a p p l i e s (Equa t ion 4 ) , ( 2 ) no

l i q u i d is h e l d up w i t h i n t h e chamber e x c e p t i n t h e sump,

(3 ) t h e l i q u i d i n t h e sump i s w e l l mixed, and (4) d r o p and

a tmosphere c o n c e n t r a t i o n s do n o t change a p p r e c i a b l y d u r i n g d r o p

f a l l t i m e . For t h i s c a s e , s i m u l t a n e o u s m a t e r i a l b a l a n c e s on

t h e g a s and l i q u i d p h a s e s g i v e :

where

K = o v e r a l l mass t r a n s f e r c o e f f i c i e n t , g L = l i q u i d h o l d - u p i n sump,

A = i n t e r f a c i a l a r e a f o r t r a n s p o r t .

T h i s e q u a t i o n would b e expec ted t o a p p l y r e a s o n a b l y w e l l t o t h e

a b s o r p t i o n of e l e m e n t a l i o d i n e by s p r a y s .

For a s l i g h t l y s o l u b l e s p e c i e s s u c h a s me thy l i o d i d e , t h e

e f f e c t of r e c i r c u l a t i o n depends on t h e r e a c t i o n r a t e . For

n e g l i g i b l e r e a c t i o n r a t e s , t h e l i q u i d w i l l app roach s a t u r a t i o n

d u r i n g one p a s s th rough t h e chamber and r e c i r c u l a t i o n w i l l n o t

i n f l u e n c e t h e g a s phase c o n c e n t r a t i o n . The n e t e f f e c t of

l i q u i d p h a s e r e a c t i o n r a t e s t o o s m a l l t o enhance a b s o r p t i o n

d u r i n g a s i n g l e p a s s b u t f a s t enough t o d e s t r o y t h e d i s s o l v e d

g a s w i t h i n t h e sump w i l l be t o make t h e s p r a y " f r e s h . " For

t h i s c a s e , t h e g a s phase washout would f o l l o w

C = exp (-$1 C

go

where

F = l i q u i d f l o w r a t e , and

H = p a r t i t i o n c o e f f i c i e n t f o r u n r e a c t e d s p e c i e s .

For s t i l l f a s t e r r e a c t i o n s , a p p r e c i a b l e a b s o r p t i o n enhancement

would o c c u r , and a n e q u a t i o n s i m i l a r t o Equa t ion ( 2 7 ) would

a p p l y , w i t h H c a l c u l a t e d t o a c c o u n t f o r t h e enhanced a b s o r p t i o n

due t o chemica l r e a c t i o n .

REMOVAL OF AEROSOL P A R T I C L E S

The mechanisms c o n t r i b u t i n g t o c a p t u r e of a e r o s o l p a r t i -

c l e s by s p r a y s i n con ta inmen t v e s s e l s i n c l u d e g r a v i t a t i o n a l

s e t t l i n g , i n e r t i a l i m p a c t i o n , Brownian d i f f u s i o n , thermo-

p h o r e s i s , d i f f u s i o p h o r e s i s , e l e c t r i c a l a t t r a c t i o n , and t h e

i n t e r c e p t i o n e f f e c t . T h i s c a p t u r e w i l l o c c u r a t t h e s u r f a c e of

f a l l i n g d r o p s and a t t h e w a l l s and f l o o r of t h e v e s s e l . The

purpose of t h e r e v i e w p r e s e n t e d h e r e i s t o show how t h e removal

r a t e due t o t h e s e v e r a l mechanisms c a n b e r e l a t e d t o t h e b a s i c

p a r a m e t e r s of t h e s y s tem.

P a r t i c l e c a p t u r e by a s p r a y may be e v a l u a t e d by c o n s i d e r -

i n g t h e s p r a y a s an assemblage of n o n i n t e r a c t i n g s i n g l e d r o p s .

T h i s a s sumpt ion may n o t be p r e c i s e l y t r u e , b u t a p p e a r s r e a s o n a b l e

f o r t h e s p r a y sys t ems of i n t e r e s t h e r e . Based on t h i s assump-

t i o n , t h e r a t e of washout may be r e l a t e d t o t h e c . o l l e c t i o n

e f f i c i e n c y f o r a s i n g l e d r o p .

A m a t e r i a l b a l a n c e on t h e g a s phase of a w e l l mixed con-

t a i n m e n t v e s s e l g i v e s , f o r t h e washout h a l f - t i m e ,

where

h = f a l l h e i g h t ,

E = t o t a l c o l l e c t i o n e f f i c i e n c y of d r o p ,

F = f l o w r a t e f o r d r o p s ,

vG = g r a v i t a t i o n a l s e t t l i n g d e p o s i t i o n v e l o c i t y ,

vW = w a l l d e p o s i t i o n v e l o c i t y of p a r t i c l e s , s u r f a c e a v e r a g e ,

,AF = f l o o r a r e a ( h o r i z o n t a l p r o j e c t i o n ) ,

AW = a r e a o f e f f e c t i v e w a l l s u r f a c e .

Equa t ion ( 2 8 ) i s f o r a s i n g l e d r o p s i z e , and a p p l i c a t i o n t o

spra.ys c o n t a i n i n g a wide spec t rum of s i z e s s h o u l d be done

i n c r e m e n t a l l y t o a c c o u n t f o r t h e e f f e c t of d r o p s i z e .

G r a v i t a t i o n a l S e t t l i n g

G r a v i t a t i o n a l s e t t l i n g w i l l c a u s e p a r t i c l e s t o d e p o s i t on

h o r i z o n t a l s u r f a c e s . For a w e l l mixed chamber, t h e g r a v i t a -

t i o n a l s e t t l i n g d e p o s i t i o n v e l o c i t y may b e t a k e n a s t h e t e r -

m i n a l s e t t l i n g v e l o c i t y of t h e p a r t i c l e s :

v = t e r m i n a l v e l o c i t y = mgB G

where

m = p a r t i c l e mass,

B = p a r t i c l e m o b i l i t y , and

g = a c c e l e r a t i o n due t o g r a v i t y .

Brownian Diffusion

Very small particles are capable of appreciable diffu-

sional transfer as a result of Brownian motion. Thus, they

will behave as gases qualitatively, but with much lower diffu-

sion coefficients. For a falling drop, the transfer coefficient

may be predicted from the Frossling equation (Equation 11)

using as diffusivity the value calculated from Einstein's (22)

equation:

where

D = diffusion coefficient for particle, P T = absolute temperature,

B = particle mobility,

k = Boltzmann's constant.

For drops moving at terminal velocity, the target efficiency is

where

EBD = target efficiency for Brownian diffusion,

v = drop terminal velocity, g

Re = Reynolds number for drop,

d = drop diameter.

Use of Equation (11) for predicting aerosol deposition due to

Brownian diffusion is not fully justified because the Schmidt

numbers associated with aerosol particles are generally much

larger than the Schmidt numbers for the experiments verifying

Equation (11) .

I n e r t i a l I m ~ a c t i o n

I n e r t i a l impac t ion o c c u r s because p a r t i c l e s a r e a b l e t o

c r o s s s t r e a m l i n e s due t o t h e i r i n e r t i a . For impac t ion on t h e

forward p a r t of a s p h e r e o r d r o p , t h e t a r g e t e f f i c i e n c y i s a

f u n c t i o n of t h e r a t i o of t h e p a r t i c l e s t o p p i n g d i s t a n c e t o t h e

d i a m e t e r of t h e s p h e r e (S tokes number). (23) The t a r g e t e f f i -

c i e n c y measured by Ranz and Wong (24) a p p e a r s t o a g r e e w i t h t h e

p r e d i c t i o n s based on p o t e n t i a l f low. Very few d a t a a r e a v a i l -

a b l e f o r p a r t i c l e s below 2 mic rons , t h e s i z e r ange of p r imary

i n t e r e s t h e r e . For S tokes numbers l e s s t h a n 0.0834, an impac-

t i o n e f f i c i e n c y of ze ro i s p r e d i c t e d .

I n t e r c e p t i o n

The i n t e r c e p t i o n e f f e c t r e q u i r e s no i n e r t i a . A p a r t i c l e

w i l l be i n t e r c e p t e d by a c o l l e c t o r i f i t s t r a j e c t o r y p a s s e s

w i t h i n one p a r t i c l e r a d i u s . For p o t e n t i a l f l o w around a s p h e r e ,

t h e i n t e r c e p t i o n t a r g e t e f f i c i e n c y is : (24)

where

d = s p h e r i c a l p a r t i c l e d i a m e t e r , P d = drop d i a m e t e r .

P r e s s u r e s u p p r e s s i o n s p r a y s w i l l e n t e r t h e conta inment

v e s s e l c o n s i d e r a b l y c o o l e r t h a n t h e atmosphere t e m p e r a t u r e .

Steam w i l l condense on t h e c o o l d r o p l e t s and t h e vapor f l u x

t h u s produced w i l l c a u s e p a r t i c l e motion toward t h e d rop . An

e s t i m a t e of t h e p a r t i c l e c a p t u r e can be made by c o n s i d e r i n g

c o n d e n s a t i o n on a s t a t i o n a r y d r o p .

The d i f f u s i o p h o r e t i c v e l o c i t y i n t h e s l i p f l o w regime f o r

s p h e r i c a l p a r t i c l e s is ( 2 5 )

where

VD = diffusiophoretic velocity,

I ML - 1.05d I + L o12 = slip factor = 0.95M + 1 2 1 2'

y2 = mole fraction of air,

Yla = mole fraction of water vapor far from particle,

D = diffusivity of water in air,

M1 = molecular weight of water,

M2 = molecular weight of air,

dl = molecular diameter of water molecules,

d2 = molecular diameter of air molecules.

The concentration gradient Vyla at the surface of a drop may

be obtained in terms of the condensation rate. The time

integrated velocity multiplied by the drop surface area gives

the volume of the gas swept to the surface. The effective

target efficiency is found to be approximately

where

ATe = temperature rise of spray drops in chamber,

pe = density of liquid spray,

AHc = latent heat of condensation per mole,

Cpe = heat capacity of spray liquid,

C = total gas concentration in containment volume, 3 mole/cm .

Thermophoresis

Thermal gradients associated with the heat transfer will

also cause particle movement towards the surface on which

vapor is condensing. However, for steam-air mixtures of

interest here, thermophoresis will be small compared to diffu-

siophoresis. (26927) Hence, thermophoresis will be neglected.

Electrical Attraction

Electrical forces can be very effective in causing par-

ticle capture by falling drops. If the particle and drop

charges are known, the target efficiency may be calculated. ( 2 8 )

Some calculations for containment sprays have been given. ( 2 9 )

For the CSE experiments, existing electrical charges were ten-

tatively concluded to be too low to provide appreciable par-

ticle collection. ( 3 0 )

Effect of Recirculation on Airborne Particle Washout

Aerosol particles captured by water sprays will exhibit

no tendency to escape from the liquid phase, and may be con-

sidered to have zero equilibrium back-pressure. Hence, recir-

culation of spray liquid will not cause a levelling in the gas

concentration of aerosol particles as would be expected for a

gaseous species such as 12. If the particle generation rate

is zero, the aerosol concentration will fall to zero as a

result of spray recirculation.

Two effects of spray recirculation which could affect the

spray washout rate are worthy of note. First, if the spray

liquid is not cooled by heat exchange, little condensation

would occur on the drop and, hence, the diffusiophoretic cap-

ture mechanism will vanish. Second, changes in the thermodynamic

conditions of the atmosphere as a result of recirculation could

cause particle growth or evaporation. This effect applies to

soluble particles such as cesium existing in the containment

atmosphere as solution drops. The amount of particle growth or

evaporation which could occur depends on the changes in rela-

tive humidity resulting from recirculation. Because the

change in relative humidity is not easy to predict with cer-

tainty, theoretical prediction of particle size change as a

result of recirculation could be considered only if verified

by experimental measurements.

EFFECT OF P A R T I A L SPRAY COVERAGE

The preceding theoretical treatment of washout by spray

drops is based on the assumption that all the gas within a

single compartment is of uniform concentration. This assump-

tion is probably valid for cases where the entire gas space is

covered by the spray. In some practical cases, the spray might

wash only a fraction of the total volume because of irregular

geometry or spray systems not purposely designed to cover all

the gas space. It is of interest to estimate the maximum con-

centration difference which might exist between sprayed and

nonsprayed regions, and to evaluate this effect on the

accuracy of predictions based on uniform concentration.

Assume that the nonsprayed and sprayed regions can be

represented by two separate volumes, V1 and V2, respectively,

as depicted in Figure 2. Each region is assumed to be indi-

vidually well mixed. Gas at concentration C2 leaves the

sprayed region and enters the unsprayed region at flow rate Q.

A similar flow of concentration C1 returns to the sprayed

region. For simplification, it is further assumed that there

is no deposition on structural surfaces within V1 or V2, and

the only removal is due to spray drops within V2 with a first - 1 order rate constant, A min .

A mass balance of the fission product material taken on the gas space V1 gives

FIGURE 2 . Schematic Diagram of Transpor t Between Sprayed and Unsprayed Regions

U N S P R A Y E D

R E G I O N

" 1 ' C 1

A s i m i l a r b a l a n c e on V 2 g i v e s

A Q

The maximum c o n c e n t r a t i o n d i f f e r e n c e w i l l occur when

Q

dC1 - dC2 - dt'

v 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

0 0 0 0 0

0 0 0 0 0 0 0 0 S P R A Y E D o o 0 0 0 R E G I O N 0 0

0 0 0 0 0

0 0 0 "2' C 2 0 0

0 0 0 0 0

0 0 0 0 0

For t h i s c a s e ,

where

V = V1 + V 2 , and

f = f r a c t i o n of combined volumes n o t s p r a y e d .

S i n c e t h e r e i s no p h y s i c a l membrane s e p a r a t i n g t h e two

r e g i o n s , t h e exchange r a t e of g a s , Q , e s p e c i a l l y f o r t h e c a s e

of c o l d s p r a y s i n a s team a tmosphere , s h o u l d b e l a r g e . The

v a l u e of V/Q i s e s t i m a t e d t o be i n t h e r a n g e of 1 t o 5 min f o r

t h e CSE sys tem. Thus, f o r removal of I 2 a t h = 0 . 5 m i n - l and

a v e s s e l i n which 20% of t h e volume i s n o t s p r a y e d , C1 s h o u l d

be 8 - 4 0 % g r e a t e r t h a n t h e c o n c e n t r a t i o n i n t h e r e g i o n washed

by t h e s p r a y . The mass of i o d i n e remaining a i r b o r n e s h o u l d be

~ 8 % g r e a t e r ( n o t a l a r g e d i f f e r e n c e ) t h a n i f t h e e n t i r e v e s s e l

volume were washed.

E X P E R I M E N T A L C O N D I T I O N S

E X P E R I M E N T A L E Q U I P M E N T

The CSE experimental equipment can be grouped for discus-

sion purposes into six systems:

the containment vessel system

the fission product simulant generation and injection

s'ys t em

the gas and liquid sampling system

0 the instrumentation system

the sample analysis system, and

the containment spray system.

Each system is described in some detail in Appendix A, and the

total system is depicted schematically in Figure 3. An outer 3 vessel of 30,680 ft called the main containment vessel, an

3 inner vessel of 2286 ft called the drywell, and the vessel of 3 4207 ,ft occupying four-fifths of the annular space between the

drywell and the main containment vessel called the wetwell are

the three interconnected vessels basically comprising the con-

tainment vessel system. The main containment vessel is 25 ft

in diam and 66.7 ft in overall height. All interior surfaces

are coated with a modified phenolic paint.*

The top of the wetwell forms a solid deck which effectively

separates the contained gases into what we term the "main room"

above the deck and the lower rooms below the deck. For the

present spray experiments, the lid of the 11-ft diam drywell

was raised to make its volume common to the main room. The 3 combined volume of this "main room" is 21,005 ft . One-fifth

of the annular space between drywell and main containment 3 vessel is a small access of 2089 ft known as the "middle room."

Below the middle room, the drywell, and the wetwell is a third

space of 3380 ft3 called the "lower room." The wetwell was

* PhenoZine 3 0 2 . T h e CarboZine Co . , S t . L o u i s , ~ i s s o u r i .

31

R U N R U N

P L A N V I E W O F N O Z Z L E A R R A N G E M E N T

S P R A Y N O Z Z L E S

/ \I \ M R Y P A C K C L U S T E R ( 1 4

13

M A I N C O N T A I N M E N T V E S

L U T I ON -\ D R O P C O L L E C T O R . A G E T A N K

)'-- T H I E F S A M P L E

W A L L T R O U G H

S P R A Y P U M P F I S S I O N P R O D U C T A E R O S O L

W E T W E L L ( C L O S E D O F F ) - S T E A M

M I D D L E ROOM

P U M P S L O W E R ROOM

2 5 f t

R E C I R C U L A T I O N p-4 P U M P

F I G U R E 3 . Schematic Diagram of Containment Arrangement Used i n CSE Spray T e s t s

s e a l e d o f f and n o t exposed t o s team o r f i s s i o n p r o d u c t s i m u l a n t

i n t h e s e e x p e r i m e n t s . Two 4 - f t diam h o l e s i n t h e deck connec t

t h e main room t o t h e midd le room, w h i l e one 4 - f t opening con-

n e c t s t h e midd le room t o t h e lower room.

Steam c o n d e n s a t e and s p r a y l i q u i d accumula te i n t h e d r y -

w e l l p o o l , t h e main v e s s e l poo l l o c a t e d i n t h e lower room, and

on t h e f l a t deck of t h e main room. The f i r s t two a r e s t i r r e d ,

sampled f r e q u e n t l y , and t h e l i q u i d volume m o n i t o r e d . The

unmoni tored l i q u i d on t h e deck d r a i n s i n t o t h e main v e s s e l

poo l a n d , t o g e t h e r w i t h t h e main room w a l l t r o u g h , i s t h e

s o u r c e of t h e main v e s s e l p o o l .

A l i n e from t h e p l a n t s team b o i l e r t e r m i n a t e s n e a r t h e

bot tom of t h e d r y w e l l t o p r o v i d e t h e s team f o r expe r imen t s a t

e l e v a t e d t e m p e r a t u r e s . For t h e two exper imen t s w i t h room tem-

p e r a t u r e a . i r a tmospheres , a s m a l l f a n was l o c a t e d a t t h e 3 bot tom of t h e d r y w e l l d i s c h a r g i n g 2 3 0 0 f t /min i n an upward

d i r e c t i o n t o p r o v i d e mixing of t h e a e r o s o l b e f o r e a c t i v a t i n g

t h e s p r a y s . .

Coleman (31) h a s d e s c r i b e d t h e method of g e n e r a t i n g t h e

f i s s i o n p r o d u c t s i m u l a n t i n d e t a i l , b u t a b r i e f d e s c r i p t i o n

is g i v e n h e r e . Four m a t e r i a l s r e l e a s e d i n t h e s e expe r imen t s

t o p e r m i t mass t r a n s f e r measurements were e l e m e n t a l i o d i n e ,

methyl i o d i d e , ces ium, and p a r t i c l e s formed by m e l t i n g u n i r -

r a d i a t e d Z i r c a l o y - c l a d U02. About 100 g of s t a b l e e l e m e n t a l

i o d i n e was e q u i l i b r a t e d w i t h a b o u t one c u r i e of as

d e s c r i b e d by Coleman. (31) The 13'1 s e r v e d a s a t r a c e r f o r

a n a l y t i c a l p u r p o s e s . When r e l e a s e was d e s i r e d , t h e f l a s k con-

t a i n i n g t h e i o d i n e was h e a t e d e l e c t r i c a l l y and a i r , swept

th rough t h e f l a s k , c a r r i e d t h e e l e m e n t a l i o d i n e t h r o u g h t h e

h o t zone of t h e UOZ m e l t i n g f u r n a c e . Some p a r t i c u l a t e -

a s s o c i a t e d i o d i n e and o r g a n i c i o d i d e s were a lways produced.

About one gram of iodine in the form of reagent grade

methyl iodide was equilibrated with 1311 in methyl alcohol in

a stainless steel U-tube. When release was desired, air was

passed through the U-tube to sweep the methyl iodide directly

into the containment vessel (bypassing the U02 furnace).

About 12 g of stable cesium as cesium carbonate was

equilibrated with about one curie of 1 3 7 ~ s in a nickel boat

and dried at a temperature <400 " C . When release was desired, . . the nickel boat was heated inductively to ~ 1 2 0 0 OC and an air

stream carried the volatilized cesium and cesium oxides through e . - the U02 furnace into the containment vessel.

In all the spray experiments, the U02 was melted for 10 min

before and during the iodine and cesium release period. Zero

time was defined as the start of iodine and cesium release. A

steam jet at the drywell acted as a compressor for injecting

the volatilized simulant into the pressurized vessel.

The suitability of the fission product simulant generated

by these methods as tracers to represent actual fission prod-

ucts in containment behavior experiments was demonstrated by

small scale tests in the Aerosol Development Facility (ADF) (33)

and elsewhere. (34)

The main gas sampling system consisted of Maypack clusters

located throughout the vapor space. This system is described

in the Appendix and by McCormack. ( 3 2 ) Supplementary gas

samples, known as "thief" Maypack samples, were taken by

manually inserting a Maypack through an airlock into the con-

tainment atmosphere and immediately withdrawing it for analysis.

Flow through each Maypack was 0.5 scfm air for 3 min duration.

Liquid sampling was extensive. Some of the liquid samples

were filtered to determine the insoluble fraction and extracted

with benzene to determine the iodine forms. The pH was deter-

mined on about half the liquid samples.

The CSE facility was adequately instrumented for character-

ization of atmospheric conditions. Details are g.iven in the

Appendix.

About 2000 samples, obtained from each experiment, were

analyzed by the CSE staff for iodine and for cesium by gamma

energy analytical techniques, and for uranium by alpha counting.

Additional details are given in the Appendix and by Coleman. (31)

The containment spray system was composed of spray solu-

tion makeup and storage tanks, a line and pump to the spray

manifold, the spray manifold inside the main containment vessel,

the spray nozzles, and a recirculation pump, line, and heat

exchanger for recirculating the liquid from the main vessel

pool back to the spray manifold. Associated instrumentation

consisted of spray solution flow rate meter, liquid level gages

on all tanks and pools, a differential pressure gage for measur-

ing pressure drop across the spray nozzles, and thermocouples

and recorders for measuring spray liquid temperature at various

locations.

E X P E R I M E N T A L P R O C E D U R E

Before each experiment was begun, a comprehensive descrip-

tion of all phases of the proposed experiment was written.

These "Run Plans," serving primarily as a guide to the opera-

tions staff in conducting the experiment, were also useful for

planning the experimental details and as handy references to

the selected conditions and procedures. Because exact condi-

tions might differ slightly from those planned, the use of

instrument charts and log sheets would usually be required.

The general procedures used in all the experiments is

outlined as follows:

1. The containment vessel was readied. Spray nozzles were

installed and tested for flow rate and coverage. Maypack

clusters were installed and tested.

BNWL- 1244

The v e s s e l was p r e s s u r i z e d w i t h a i r and l e a k t e s t e d .

The a i r i n t h e v e s s e l was v e n t e d u n t i l b a r o m e t r i c p r e s s u r e

and room t e m p e r a t u r e p r e v a i l e d . The v e s s e l was t h e n

s e a l e d and t h e a i r r e c i r c u l a t e d th rough an a b s o l u t e f i l - - 3 t e r u n t i l c o n d e n s a t i o n n u c l e i c o n c e n t r a t i o n was ~ 3 0 0 cm .

For t e s t s where a s t e a m - a i r a tmosphere a t e l e v a t e d tem-

p e r a t u r e and p r e s s u r e was s p e c i f i e d , s team was f e d i n t o

t h e sys tem n e a r t h e bot tom of t h e d r y w e l l .

When t h e d e s i r e d t e m p e r a t u r e i n t h e main room (250 + 2 OF)

was r e a c h e d , a s measured b y an a v e r a g e of s e v e r a l thermo-

c o u p l e s , t h e s team f e e d was reduced t o t h a t r e q u i r e d t o

m a i n t a i n s t e a d y t e m p e r a t u r e i n t h e main room. (For t h e

two room- tempera ture e x p e r i m e n t s , t h i s was n o t necessa . ry ,

of c o u r s e ) .

The l i q u i d p o o l s formed b y s team c o n d e n s a t e d u r i n g warmup

were d r a i n e d and d i s c a r d e d .

The U02 was m e l t e d and U 0 2 - Z i r c a l o y p a r t i c l e s i n j e c t e d

i n t o t h e con ta inmen t a tmosphere by an a i r f l o w of 3 1 . 8 f t /min (STP). The r e l e a s e p o i n t was a t mid e l e v a -

t i o n i n t h e d r y w e l l .

A f t e r 10 min of U 0 2 - Z i r c a l o y p a r t i c l e i n j e c t i o n , t h e

i o d i n e and cesium r e l e a s e was s t a r t e d . Methyl i o d i d e was

t h e n r e l e a s e d th rough a s e p a r a t e l i n e . Ten m i n u t e s a f t e r

i o d i n e and cesium r e l e a s e s t a r t e d , a l l v a l v e s were c l o s e d .

Zero t ime was d e f i n e d a s s t a r t of i o d i n e r e l e a s e .

Dur ing s i m u l a n t i n j e c t i o n and th roughou t t h e r ema inde r of

t h e expe r imen t (24-36 h r ) , s team f e e d was c o n t i n u e d a t

t h e r a t e p r e v i o u s l y de te rmined n e c e s s a r y t o m a i n t a i n t h e

t e m p e r a t u r e a t 250 O F i n t h e main room.

Samples were t a k e n over a 30-min p e r i o d t o d e t e r m i n e , i n

t h e absence of s p r a y s , t h e b e h a v i o r of t h e f i s s i o n p r o d u c t

s i m u l a n t m a t e r i a l s .

The f i r s t s p r a y p e r i o d was s t a r t e d a t t h e s p e c i f i e d t i m e .

F r e s h s o l u t i o n a t room t e m p e r a t u r e from t h e s t o r a g e t a n k

o u t s i d e con ta inmen t was u s e d . A s e t of g a s samples was

t a k e n d u r i n g and immedia te ly f o l l o w i n g t h i s s p r a y .

1 2 . L i q u i d samples were t a k e n f r e q u e n t l y d u r i n g t h e f i r s t

s p r a y p e r i o d from l i q u i d p o o l s and from w a l l t r o u g h and

s p r a y d r o p c o l l e c t o r s .

1 3 . Upon comple t ion of t h e f i r s t s p r a y p e r i o d , Maypack g a s

samples a g a i n were t a k e n a t v a r i o u s t i m e s t o d e t e r m i n e

t h e n a t u r a l b e h a v i o r .

14. The second s p r a y p e r i o d was s t a r t e d a t t h e s p e c i f i e d t i m e .

T h i s p e r i o d was c o n t i n u e d f o r a t o t a l of 4 0 min of f r e s h

s p r a y , i n c l u d i n g t h e f i r s t p e r i o d .

15 . During a l l s p r a y p e r i o d s , t h e p r imary c o n t r o l was t h e d i f -

f e r e n t i a l p r e s s u r e a c r o s s t h e s p r a y n o z z l e s . T h i s p r e s s u r e

was h e l d c o n s t a n t t o m a i n t a i n t h e same d rop s i z e d i s t r i -

b u t i o n . I n Runs A 6 , A 7 , and A8, t h e t e m p e r a t u r e dropped

from t h e i n i t i a l 250 O F because of i n t r o d u c t i o n of c o l d

s p r a y , b u t t h e s team f e e d was l e f t a t i t s o r i g i n a l low

s e t t i n g .

16 . A f t e r a s p e c i f i e d w a i t i n g p e r i o d w i t h no s p r a y ( u s u a l l y

o v e r n i g h t , b u t i n Run A8 w i t h i n a few h o u r s ) , a t h i r d

s p r a y p e r i o d was s t a r t e d . T h i s s p r a y was produced by

r e c i r c u l a t i n g t h e s o l u t i o n from t h e main con ta inmen t

v e s s e l p o o l . The h e a t exchanger was bypassed s o t h a t t h e

s o l u t i o n was h o t , u s u a l l y about 2 0 0 O F . The vapor tem-

p e r a t u r e would u s u a l l y r e t u r n t o 2 5 0 OF by t h e t ime t h e

t h i r d s p r a y s t a r t e d .

1 7 . A f o u r t h f r e s h , c o l d s p r a y (sodium t h i o s u l f a t e , b o r i c

a c i d , pH 9 . 4 ) was used i n kuns A 7 and A8.

1 8 . A f t e r t h e l a s t s p r a y , a f i n a l s e t of samples was t a k e n ,

t h e s team f e e d s h u t o f f , and t h e v e s s e l a l lowed t o c o o l

t o a b o u t 100 O F . The a i r was purged th rough a c h a r c o a l

a d s o r b e r t o a s t a c k and t h e v e s s e l was e n t e r e d t o r e t r i e v e

t h e s a m p l e r s .

19. After sample hardware recovery, the vessel was resealed "

h and steamed for several days with alternate water spray- . ing to decontaminate the painted surfaces. w

20. Each of the Maypacks was removed from the cluster assem- - . - blies and carefully marked with its proper identification.

The Maypacks were brought into a sample preparation room

and disassembled. Each component (or group of components)

was carefully removed and placed in a small, flat poly-

ethylene bag marked with its proper identification, and

heat sealed. The charcoal granules were poured into a

small plastic jar.

21. Liquid samples were taken in 500-ml polyethylene bottles,

marked as to volume or aliquot, and identification sym-

bols applied. Specified samples were filtered, extracted,

or measured for pH.

22. Deposition coupons were placed in flat polyethylene bags,

marked, and heat sealed.

23. Gamma analysis began during the experiment and continued

on a 24-hr basis for about one week.

24. Alpha analysis of Maypack filters continued for several

weeks after the experiment.

T E S T C O N D I T I O N S

The conditions used in each experiment are best reported

in tabular form. Table 1 lists the physical dimensions common

to all the experiments. Table 2 describes the spray nozzles

used and Table 3 lists the atmospheric conditions. Table 4 A

presents spray solution details and applicable flow rates, and

Table 5 lists the starting and stopping times of each spray I

period.

TABLE 1. P h y s i c a l C o n d i t i o n s Common t o A l l Sp ray Exper iments

Volume above deck i n c l u d i n g d r y w e l l

S u r f a c e a r e a above deck i n c l u d i n g d r y w e l l

S u r f a c e area /volume

Cross s e c t i o n a r e a , main v e s s e l

Cross s e c t i o n a r e a , d r y w e l l

Volume, midd le room

S u r f a c e a r e a , midd le room

Volume, lower room

S u r f a c e a r e a , lower room

T o t a l volume of a l l rooms

T o t a l s u r f a c e a r e a , a l l rooms

Drop f a l l h e i g h t t o deck 33.8 f t 1 0 . 3 m

Drop ' f a l l h e i g h t t o d r y w e l l bot tom 50.5 f t 15 .4 m

S u r f a c e c o a t i n g

Thermal i n s u l a t i o n

A l l i n t e r i o r s u r f a c e s c o a t e d

w i t h p h e n o l i c p a i n t ( a >

A l l e x t e r i o r s u r f a c e s cove red

w i t h l - i n . f i b e r g l a s s

i n s u l a t i o n (b )

a . Two c o a t s P h e n o Z i n e 302 o v e r o n e c o a t P h e n o Z i n e 300 p r i m e r . The C a r b o Z i n e C o . , S t . L o u i s , M i s s o u r i .

b . k = 0 . 0 2 7 B t u / ( h r l ( f t 2 ~ I ° F / f t i a t 200 O F , T y p e PF-615, Owens- Corning F i b e r g Z a s C o r p .

TABLE 2 . Nozz le s Used i n CSE Spray E x p e r i m e n t s

Runs A3, 4 , 6 , 7

Nozz le Type:

*

1

. - S p r a y i n g Systems Co. 3 / 4 - 7G3

Nozzle C h a r a c t e r i s t i c s : Fog Type, f u l l cone

A3 A 4 , 6 , 7 . .

Number 3 1 2

Layout T r i a n g u l a r Squa re G r i d . . *

S p a c i n g 1 0 f t 5 i n . 6 f t a p a r t a p a r t

P r e s s u r e 40 p s i d 40 p s i d

Rated Flow 4 gpm 4 gPm

MMD 1210 p 1210 11

CI 1 . 5 1 . 5 g

Run A8

Nozzle Type: S p r a y i n g Sys tems Co. 3 / 8 A 20

Nozz le C h a r a c t e r i s t i c s : F i n e a t o m i z a t i o n , h o l l o w cone

Number u s e d 1 2

Lavout S a u a r e G r i d

Spac ing

P r e s s u r e

6 f t a p a r t

40 p s i d

Rated Flow 4 gPm

MbI D 770 il

BNWL- 1 2 4 4

TABLE 3. Atmospheric Conditions in CSE Spray Experiments

Ru n Run Run Run Run A3 -- A4 A6 A7 A 8

C o n t a i n m e n t v e s s e l i n s u l a t e d No No Yes Yes Yes

F o r c e d a i r c i r c u l a t i o n ( a > Yes Yes No No No

S t a r t o f 1st S p r a v a p o r t e m p . , OF^^) 7 7 7 7 255 248 .7 250 P r e s s u r e , p s i a 1 4 . 6 1 4 . 6 4 4 . 2 5 0 . 0 5 0 . 7 R e l a t i v e h u m i d i t y , % 70 88 100 100 100

End o f 1st S p r a y Vapor t e m p . , OF (b 1 7 7 77 229 2 3 4 . 5 243 P r e s s u r e , p s i a 1.4.6 1 4 . 6 3 8 . 6 4 4 . 4 4 8 . 2

S t a r t o f 2nd S p r a y Vapor t e m p . , ' ~ ( ~ 1 7 7 7 7 237 240 243 P r e s s u r e , p s i a 1 4 . 6 1 4 . 6 4 0 . 8 4 6 . 0 4 9 . 3

End o f 2nd S p r a y Vapor t e m p . , O F (b 1 7 7 7 7 202 203 1 8 8 P r e s s u r e , p s i a 1 4 . 6 1 4 . 6 2 9 . 5 36 3 4 . 1

S t a r t o f 3 r d S p r a y Vapor t e m p . , ' ~ ( ~ 1 7 7 7 7 246 248 217 P r e s s u r e , p s i a 1 4 . 6 1 4 . 6 4 3 . 9 46 .8 4 1 . 5

End of 3 r d S p r a y Vapor t e m p . , O F (b 1 7 7 7 7 233 230 218 P r e s s u r e , p s i a 1 4 . 6 1 4 . 6 40 .7 4 1 . 8 3 2 . 2

S t a r t o f 4 t h S p r a y v a p o r temp. , O F Cb) (c ) (c) (C > 232 247 P r e s s u r e , p s i a ( c > ( c > ( c ) 4 2 . 4 5 2 . 4

End o f 4 t h S p r a y Vapor t e m p . , OF (b ) (c ) ( c> ( C > 1 9 2 1 7 5 P r e s s u r e , p s i a ( c > (C > ( c ) 3 2 . 7 3 2 . 4

a. Fan without d u c t Located in bottom of drywett. 2400 ft3/ min discharge.

b. Average of 5 thermocoupZes Located at various elevations and radii.

c. No fourth spray.

TABLE 4 . Spray Flow Ra tes and S o l u t i o n s Used i n CSE Exper iments t @ '

Run Run Run Run Run 'r

A3 A 4 A6 A 7 A8 I

- 5 -

1st Spray T o t a l f l o w r a t e , gpm 12 .8 49 49 49 50 Volume s p r a y e d , g a l 128 490 490 490 150 Spray ing p r e s s u r e ,

p s i d 40 40 40 40 40 S o l u t i o n (a > ( a > (b 1 ( c ) ( b 1

2nd Spray T o t a l f l o w r a t e , gpm Volume s p r a y e d , g a l Spray ing p r e s s u r e ,

ps i d S o l u t i o n

3 r d Spray T o t a l f l o w r a t e , gpm Volume s p r a y e d , g a l Spray ing p r e s s u r e ,

ps i d S o l u t i o n

4 t h Spray T o t a l f l o w r a t e , gpm (g) (g> (g 1 48.6 50.4 Volume s p r a y e d , g a l (g 1 (g 1 (g ) 2428 2520 Spray ing p r e s s u r e ,

ps i d (g) (g) (g ) 40 40 S o l u t i o n (g 1 (g 1 (g 1 If > (f

a . F r e s h , room t e m p e r a t u r e . 5 2 5 p p m b o r o n a s H3B03 i n demin- e r a l i z e d w a t e r . NaOH added t o pH o f 9 . 5 .

b . F r e s h , room t e m p e r a t u r e . 3000 p p m b o r o n a s H3B03 i n d e m i n e r a l i z e d w a t e r . NaOH added t o pH o f 9 . 5 .

c . F r e s h , room t e m p e r a t u r e . 3000 ppm b o r o n a s H3B0 i n d e m i n e r a l i z e d w a t e r . No NaOH added . pH 5 . 3

d . F r e s h , room t e m p e r a t u r e d e m i n e r a l i z e d w a t e r .

e . S o l u t i o n i n main v e s s e l sump r e c i r c u l a t e d . No h e a t e x c h a n g e r u s e d .

f . F r e s h , room t e m p e r a t u r e . I w t % Na2S203, 3 0 0 0 p p m b o r o n a s H3B03 i n d e m i n e r a l i z e d w a t e r . NaOH added t o pH 9 . 4 .

g . No f o u r t h s p r a y .

TABLE 5. Timing of Spray Periods

Time a f t e r S t a r t of I o d i n e R e l e a s e . min

Run A3

Run Run A4 A6

Run A 7

Run A8

F i r s t Spray S t a r t S top D u r a t i o n

Second Spray S t a r t s t o p D u r a t i o n

T h i r d Spray S t a r t S top D u r a t i o n

F o u r t h Spray S t a r t S t o p D u r a t i o n

a. No fourth spray.

The c o n d i t i o n s of each exper iment d i f f e r e d i n some impor-

t a n t a s p e c t . Run A3 used a low f l o w r a t e s p r a y i n room tem-

p e r a t u r e a i r . Run A4 was a d u p l i c a t e e x c e p t f o r an i n c r e a s e

i n t h e f l o w r a t e by a f a c t o r of f o u r . Run A6 was a d u p l i c a t e

of A4 e x c e p t f o r t h e u s e of a s t e a m - a i r a tmosphere a t 250 O F

i n s t e a d o f room t e m p e r a t u r e a i r .

Run A7 c o n d i t i o n s were n e a r l y t h e same a s t h o s e i n Run A6,

b u t an a c i d s p r a y was u s e d . A l s o , a r u p t u r e d i s c on t h e wet -

w e l l b roke i n t h i s exper iment j u s t b e f o r e t ime z e r o , t h u s

r e q u i r i n g a d d i t i o n of t h e 4207 f t 3 we twe l l volume t o t h e 3 26,477 f t s p a c e i n t h e normal th ree - room s p a c e f o r p r e s s u r e

c a l c u l a t i o n s . However, n o t much s team e n t e r e d t h e we twe l l

because t h e b r e a k was n e a r t h e b o t t o x of t h e v e s s e l , and v e r y

l i t t l e i o d i n e o r cesium was r e c o v e r e d a f t e r w a r d s from t h e

we twe l l a r e a .

A n o z z l e g i v i n g a s m a l l e r d rop s i z e d i s t r i b u t i o n r e p r e -

s e n t e d t h e c h i e f change i n Run A 8 . The n o z z l e s used i n t h i s

expe r imen t were of t h e hol low cone t y p e , w h i l e t h o s e i n e a r l i e r

t e s t s were of t h e f u l l cone t y p e .

S A M P L E A N A L Y S I S AND D A T A H A N D L I N G

Between 1500 and 2 0 0 0 samples of l i q u i d s , d e p o s i t i o n

coupons , and Maypack components were o b t a i n e d from e a c h e x p e r i -

ment. These samples were a n a l y z e d f o r i o d i n e and cesium by

t h e CSE s t a f f by gamma ene rgy a n a l y s i s . A m u l t i c h a n n e l a n a l y z e r

sys tem coup led t o a s m a l l d i g i t a l computer (31,35,36) c o n v e r t e d

t h e raw c o u n t s t o c o n c e n t r a t i o n v a l u e s , c o r r e c t e d f o r r a d i o -

d e c a y , a l i q u o t s , r o t o m e t e r p r e s s u r e d i f f e r e n c e s , and atmo-

s p h e r i c changes . The o u t p u t , s t o r e d on magnet ic t a p e , was

l a t e r t r a n s f e r r e d t o a t a p e c o m p a t i b l e w i t h a l a r g e r computer .

The f i n a l o u t p u t was c o n c e n t r a t i o n d a t a i n t a b u l a r form c o r -

r e l a t e d i n t e rms of f i s s i o n p r o d u c t s i m u l a n t form and l o c a t e d

w i t h i n con ta inmen t and t ime of sampl ing . The computer a l s o

p r o v i d e d a v e r a g e s and s t a n d a r d d e v i a t i o n s , s u b t r a c t e d "b lank"

v a l u e s , c o r r e c t e d f o r e l e m e n t a l i o d i n e a d s o r p t i o n on Maypack

f i l t e r s , and made o t h e r t i m e - s a v i n g computa t ions .

Some equipment m a l f u n c t i o n s and o p e r a t o r e r r o r s a r e t o be

e x p e c t e d i n l a r g e - s c a l e expe r imen t s such a s t h o s e r e p o r t e d

h e r e . F o r t u n a t e l y , t h e number and s e v e r i t y of t h e s e c a s e s t

were low, and t h o s e encoun te red had l i t t l e e f f e c t on t h e o v e r -

a l l a c c u r a c y of t h e e x p e r i m e n t a l measurements . However, some

anomolous r e s u l t s no ted on t h e f i r s t machine d a t a o u t p u t s h e e t s

f o r e v e r y expe r imen t were checked, and e n g i n e e r i n g judgement

was used i n d e c i d i n g whether t h e d a t a were v a l i d o r s h o u l d be

d i s c a r d e d . A r e v i s e d d a t a o u t p u t was t h e n o b t a i n e d from t h e

computer .

R E S U L T S A N D D I S C U S S I O N

R E L E A S E T O T H E C O N T A I N M E N T A T M O S P H E R E

O v e r a l l Mass Ba lances

The p r o c e d u r e s and s t a r t i n g masses f o r g e n e r a t i n g and

i n j e c t i n g t h e f i s s i o n p r o d u c t s i m u l a n t m a t e r i a l s were n e a r l y

i d e n t i c a l i n e a c h of t h e f i v e e x p e r i m e n t s . T a b l e s 6 and 7

g i v e t h e o v e r a l l mass b a l a n c e s f o r i o d i n e and ces ium, r e s p e c -

t i v e l y . The t o p h a l v e s of t h e t a b l e s r e l a t e t o t h e g e n e r a t i o n

and r e l e a s e t o t h e c o n t a i n m e n t , w h i l e t h e lower h a l v e s a r e

based on t h e masses r e l e a s e d i n t o t h e con ta inmen t v e s s e l .

A f t e r t h e r e l e a s e p e r i o d was comple ted , v a l v e s were

c l o s e d t o i s o l a t e t h e g e n e r a t i o n equipment and d e l i v e r y l i n e

from t h e con ta inmen t v e s s e l . The amount of m a t e r i a l r e t a i n e d

i n t h e g e n e r a t i o n equipment and d e p o s i t e d i n t h e d e l i v e r y l i n e

was de te rmined by c a r e f u l d e c o n t a m i n a t i o n and a n a l y s i s . The

s m a l l amount of m a t e r i a l withdrawn by s a m p l e r s on t h e d e l i v e r y

l i n e was a l s o accoun ted f o r . The sum of t h e m a t e r i a l found

e x t e r i o r t o t h e v e s s e l was s u b t r a c t e d from t h e known s t a r t i n g

mass t o d e t e r m i n e t h e amount a c t u a l l y d e l i v e r e d t o t h e c o n t a i n

ment v e s s e l . The mass of i o d i n e d e l i v e r e d , l i s t e d i n T a b l e 6 ,

i s b e l i e v e d t o be a c c u r a t e t o 2 5 % . For ces ium, l e s s comple te

r e l e a s e and h i g h e r p l a t e o u t i n t h e d e l i v e r y l i n e r e s u l t e d i n

l e s s c e r t a i n t y of i t s d e l i v e r e d mass. The v a l u e s l i s t e d i n

Tab le 7 a r e b e l i e v e d a c c u r a t e t o 210%.

The i n i t i a l g a s phase c o n c e n t r a t i o n , C can be c a l c u - 20 '

l a t e d by d i v i d i n g t h e mass d e l i v e r e d by t h e g a s s p a c e above

t h e main d e c k , i n c l u d i n g t h e open- topped d r y w e l l . T h i s volume, 3 595 m , i s t h e p r o p e r volume t o u s e a t t i m e s s h o r t l y a f t e r

i n j e c t i o n b e c a u s e , a s w i l l be shown l a t e r , t h e i o d i n e and

cesium were d i s p e r s e d u n i f o r m l y t h r o u g h o u t t h i s r e g i o n , w i t h

o n l y t r a c e s d i f f u s i n g i n t o t h e r e g i o n s below deck i n i t i a l l y .

. ,

a :I 0 a 9 0 O b c n M Q d b T - L n C O N M r(

c : m o r ( + o a M c n m o L o ~ 01 . . . M . :~ . . . . . . . . rl 1 s - 0 - -- r-4 m m m M o o o L n N

0 a l & l !-. GI , L n LO d

-rl

O d * N 0 O b L O 0 M . . . 21 0 - L n

. . 0 0

0 M N \D I d

V o w * 0 0 0 0 rl CO

4 rl

m

5 k U

xi- r. LC

N

o m a N rn W O C n 0 0 C O P . 0 UJ . . . . . O M N 0 iD d

r . o o w i D N O O N L O . . . . . N O O O N

No material balance is given for uranium because liquid

samples were not analyzed for this material. On the basis of

tests in the Aerosol Development Facility (ADF), an estimated

100 mg/min of combined oxides of uranium, zirconium, and tin

were delivered to the containment atmosphere, about half of

which was uranium. On the basis of Maypack gas samples, the

initial gas phase concentration of uranium ranged from 2 to 3 15 mg/m .

Tables 6 and 7 also show the recovery of iodine and

cesium from the containment vessel at the termination of each

experiment. The material found in four locations are reported

as (1) the liquid pools accumulated in vessel sumps, (2) the

material removed in samples, (3) the material remaining air-

borne and purged to stack, and (4) the surface decontamination

liquid. Not measured directly was the material remaining on

structural surfaces after decontamination efforts were com-

pleted. The latter was estimated by two methods. The method

shown in Tables 6 and 7 was to assume that any materials not

found elsewhere were still on the surfaces. A second method,

discussed in an ensuing section, was to extrapolate the amount

found on small deposition coupons located throughout the

vessel to an equivalent amount on the total surface area

exposed to the vapor phase. The latter method is believed to

be less accurate but serves as a check on the first.

Although there were variations from test to test, as

might be expected because of the differences in conditions

employed, the general pattern of the fate of iodine and

cesium was similar. The average distribution between the five

locations, expressed as percent of the mass delivered to the

containment vessel, is given in Table 8, along with the

standard deviation between tests.

TABLE 8. Average Distribution of Iodine and Cesium at End of Experiment

Iodine

Percent of Delivered Mass, a

Liquid Pools 5 2 . 8 t 7.4

Samples 3.0 + 5.3

Gas Phase 0.4 t 0.4

Decontamination 3 . 8 i: 3.6

Surf aces 40.0 t 12.2

Cesium

Percent of Delivered Mass, 0

It is evident that, although nearly all the cesium was

found. in the liquid phase, a large fraction of the iodine

remained on the painted vessel surfaces. These behaviors are

consistent with experiences in small-scale ADF tests ( 3 3 ) and

with iodine-paint reaction rates published by BattePle-

Columbus. (37) It should be remembered that sprays were not

operated until 20 or 30 min after the end of aerosol injection

and, that during this period, up to 70% of the iodine had

plated out on surfaces (or in condensate film). A lower frac-

tion of iodine would presumably have been found reacted with

paint if the containment sprays had been operated during the

release period.

Visual Observations of the Containment Atmosphere -

A view of the interior of the containment vessel was

possible by means of a 6-in. diam window and lights located

within the vessel. The window was kept free of condensation

by a heat lamp located externally. The visual observations,

similar in all the experiments, are summarized as follows.

When steam was injected into the cold, sealed vessel, a

fog formed which rapidly filled the vapor space and reduced

visibility to 6 to 8 ft. After the desired temperature of

250 O F was attained and the steam feed was reduced to that

r e q u i r e d t o m a i n t a i n t h e r m a l e q u i l i b r i u m , t h e f o g d i s s i p a t e d

and t h e a tmosphere was c l e a r e x c e p t f o r a v e r y l i g h t m i s t .

Convec t ion v e l o c i t i e s were no ted b o t h by mot ion of aluminum

f o i l r i b b o n s , t h e swaying of l i n e s , and by r e c o r d i n g anemome-

t e r s . * Motion of t h e o c c a s i o n a l m i s t p a r t i c l e s obse rved was

e r r a t i c b u t g e n e r a l l y downward a t 50 t o 100 f t / m i n . Not much

change was n o t i c e d when uranium and Z i r c a l o y o x i d e fumes were

i n j e c t e d , b u t a s soon a s r e l e a s e of t h e m i x t u r e o f ces ium and

i o d i n e began , a dense c l o u d of fog appea red which r a p i d l y

f i l l e d a l l t h e s p a c e viewed. The v i s i b i l i t y was r educed t o

a b o u t one f o o t by t h e end of t h e r e l e a s e p e r i o d . A d e f i n i t e

v i o l e t t i n g e was e v i d e n t immedia te ly a f t e r I 2 i n j e c t i o n .

V i s i b i l i t y s l o w l y improved t o 3 t o 5 f t a t t h e t ime t h e con-

t a i n m e n t s p r a y was f i r s t o p e r a t e d . V i s i b i l i t y improved s l i g h t l y

d u r i n g t h e f i r s t s h o r t s p r a y p e r i o d . The s p r a y appea red s i m i l a r

t o a h a r d r a i n f a l l e x c e p t t h a t t h e d r o p s were s m a l l e r . Some-

t i m e s t h e y seemed t o swirl and o c c a s i o n a l l y seemed t o v a r y i n

i n t e n s i t y . Convect ion v e l o c i t i e s i n c r e a s e d d u r i n g t h e s p r a y

p e r i o d . A s soon a s t h e s p r a y s t o p p e d , which was v e r y a b r u p t

b e c a u s e of t h e e l e c t r i c b a l l v a l v e c o n t r o l , t h e a tmosphere

became v e r y c l e a r . Some r e s i d u a l s m a l l d r o p l e t s remained

v i s i b l e f o r 1 t o 2 min. T h i s b e h a v i o r was t h e same i n e a c h

t e s t , even f o r Run A8 when t h e f i r s t s p r a y l a s t e d o n l y 3 min.

Immedia te ly a f t e r t h e s p r a y s t o p p e d , t h e w a l l s were s e e n

t o have a t h i n s h e e t of s p r a y s o l u t i o n r u n n i n g down i n waves.

T h i s r u n - o f f d e c r e a s e d w i t h i n a few m i n u t e s a n d , a f t e r a b o u t

10 min t h e w a l l s appea red t o become d r y . T h i s d r y i n g appea red

t o commence a s a f r o n t p r o g r e s s i n g s l o w l y from t h e upper r e g i o n

above t h e v iewing a r e a downward.

When t h e second and t h i r d s p r a y p e r i o d s were s t a r t e d , a

f o g became a p p a r e n t t o s e v e r a l o b s e r v e r s even though v i s i b i l i t y

* Heated thermopile type--Manufactured by the Hastings-Raydist Co., Hampton Virginia.

was hindered by density of the spray drops. Termination of

the second and third sprays resulted in the same observations

described for the first spray termination.

Aerosol and Iodine Forms in - the Containment Atmosphere

Iodine was released in three intended forms consisting of

elemental 12, methyl iodide, and a small fraction attached to

solid particles. Undetermined forms were probably also

released in small amounts. The relative proportion of these

amounts as sampled from the del.ivery lines was 0.97, 0.01,

0.02, and (0.01, respectively. As soon as they entered the

steam-air containment atmosphere, these relative proportions

changed rapidly due to absorption of some elemental iodine in

fog drops (38) and different rates of deposition on surfaces.

The typical fraction of iodine in each of the four forms at the

start of the first spray period is listed in Table 9.

TABLE 9 . Iod ine Form a t Beginning of F i r s t Spray

Average of -- Form 5 Experiments, %

Elemental I2 86 t 6.3

Particulate-associated 9.3 + 3.9 Methyl Iodide 2.4 ir 0.4

Unknown (a> 2.4 t 1.8

a . M a t e r i a l d e p o s i t e d on i n l e t t o Maypack and on c h a r c o a Z p a p e r .

Cesium was volatilized as cesium metal and cesium oxide

particles of about 0.25 y h1I\lD. Some growth occurred by agglom-

eration d~ring the 18-sec transit time to the containment

atmosphere. The rapid fog formation observed upon release to

the containment atmosphere is indicative of the rapid dissolu-

tion of cesium particles to form solution droplets. A later section discusses particle size measurements.

S P R A Y O P E R A T I O N

S ~ r a v Svstem C h a r a c t e r i s t i c s

The s p r a y sys tem f o r t h e t e s t s was a r r a n g e d t o p r o v i d e

(1) un i fo rm d i s t r i b u t i o n of t h e s p r a y ove r t h e v e s s e l c r o s s

s e c t i o n , (2) minimum impingement of s p r a y on t h e v e s s e l w a l l ,

(3) c o n t r o l of f l o w r a t e and n o z z l e p r e s s u r e , (4) known d u r a -

t i o n of e a c h s p r a y p e r i o d , and (5) known f r a c t i o n of t h e v e s s e l . . volume s p r a y e d . By a r r a n g i n g t h e s p r a y n o z z l e s i n a r e g u l a r

a r r a y w i t h t h e d r o p l e t e n v e l o p e s of each n o z z l e j u s t t o u c h i n g

t h e w a l l and t h e a d j a c e n t n o z z l e e n v e l o p e s , t h e f i r s t and s e c -

ond r e q u i r e m e n t s were met r e a s o n a b l y w e l l . L i q u i d d i s t r i b u -

t i o n was measured d u r i n g p r e r u n t e s t s by measur ing t h e

c o l l e c t i o n r a t e i n 50 j a r s l o c a t e d a t t h e bot tom of t h e v e s s e l ,

and by m o n i t o r i n g t h e l i q u i d f l o w from t h e w a l l t r o u g h and t o

t h e main sump and t o t h e d r y w e l l sump. The obse rved l i q u i d

d i s t r i b u t i o n f o r t h e v a r i o u s s p r a y r u n s i s g i v e n i n T a b l e 1 0 .

TABLE 10. Measured Spray Liquid Distribution in CSE Tests

T o t a l Spray Volume Recovered, %

Wall Dry Well Deck Distr. Trough Main Sump Sump t l a , %

Cross S e c t i o n Area , % 2 . 0 78 .5 1 9 . 5 - - -

Run A3 (a ) 0 .7 62 .8 37 .5 64.8

Run ~ 4 ~ ~ ) 1 0 . 9 68.9 20.2 46.7

Run A6 and A 7 ( b ) 2 . 1 68 .4 28.5 - - - Run A8 (a) ~ 6 . 0 73.0 21.0 46.2

a . Measured d u r i n g shakedown t e s t .

b . Measured from l i q u i d ZeveZ change dur ing r u n . Normal c o n d e n s a t i o n d e d u c t e d .

Although the same nozzle arrangement was used in Runs A4,

6, and 7, a change in spray distribution can be seen between

Runs A4 and A6. This change, due to the increased drag on the

drops at the higher containment atmosphere pressures, results

in fewer drops reaching the vessel walls and a slightly higher

amount of liquid reaching the drywell sump. Also given is the

standard deviation of the distribution of the liquid on the

main and drywell decks as measured by the volume captured in

jars during the shakedown tests.

The fraction of the gas volume in the main room washed by

the sprays was estimated on the basis of the known spray height

and envelope diameter. While the fraction of the gas space

sprayed does not appear as a parameter in removal equations

(for the "well mixed" model) , spraying a substantial fraction of the gas space eases the necessity for the gas to be well

mixed. It is estimated that spray drops washed 5 0 % of the

vessel volume in Run A3, and 8 0 % in Runs A4, A6, A7, and A8,

for the nozzle arrangements used.

The spray flow was controlled to maintain a constant

pressure drop across the spray nozzles. By maintaining a con-

stant nozzle pressure drop, it was hoped that the drop size

spectrum could be kept reasonably constant during the spray

test. The flow to the nozzles was measured by use of a cali-

brated orifice and a strip chart recorder. Spray duration was

determined by use of a fast operating ball valve to obtain an

abrupt flow start and stop. All spray system piping was primed

prior to the test with the solution to be used. In addition,

the nozzles were fed from the top of the header to minimize

draining at the end of the spray period. It is estimated that

spraying times were known to within k 0 . 2 min, total flow t4%,

and AP (across the nozzles) ?1 psi. The measured flow rates

for the runs are summarized in Table 4.

The s p r a y d r o p d i a m e t e r , an i m p o r t a n t p a r a m e t e r , was

changed f o r Run A 8 by u s i n g a d i f f e r e n t n o z z l e . The d r o p s i z e

used f o r e a c h t e s t was obtaine-d from d a t a p r o v i d e d by t h e

n o z z l e m a n u f a c t u r e r . * The d r o p s i z e spec t rum was d e t e r m i n e d

by t h e m a n u f a c t u r e r by e l e c t r o n i c a l l y scann ing a l a r g e number

of d r o p images formed on a v i d i c o n t u b e . The obse rved s i z e

d i s t r i b u t i o n s d e v i a t e o n l y s l i g h t l y from l o g - n o r m a l , o r can be

f i t t e d w e l l t o an upper l i m i t t y p e of d i s t r i b u t i o n . Both d i s -

t r i b u t i o n s have been used t o p r e d i c t t h e b e h a v i o r of t h e CSE

s p r a y s . No e s t i m a t e o r l i t e r a t u r e r e f e r e n c e s t o t h e a c c u r a c y

of t h e d r o p s i z e i n f o r m a t i o n p r o v i d e d by t h e m a n u f a c t u r e r can

be made, and a t t h i s t ime no independen t d rop s i z e measure-

ments a r e a v a i l a b l e . However, t h e e l e m e n t a l i o d i n e removal 2 r a t e i s a p p r o x i m a t e l y r e l a t e d t o l / d , and t h e good agreement

between t h e measured removal r a t e s r e p o r t e d i n a l a t e r s e c t i o n

of t h i s r e p o r t and t h o s e c a l c u l a t e d u s i n g t h e m a n u f a c t u r e r ' s

d r o p s i z e d a t a i n d i c a t e s t h e u s e of r e a s o n a b l e d r o p s i z e s .

Heat Removal bv S ~ r a v s

While t h e p r imary purpose of t h e CSE s p r a y t e s t s was t o

s t u d y f i s s i o n p r o d u c t r emova l , p r e s s u r e s u p p r e s s i o n i n f o r m a t i o n

was a l s o o b t a i n e d . The t e m p e r a t u r e s and p r e s s u r e s a t t h e s t a r t

and end of t h e s p r a y p e r i o d s a r e l i s t e d i n T a b l e 3 f o r t h e

v a r i o u s r u n s . The c o n d i t i o n s d u r i n g a t y p i c a l s p r a y a r e shown

i n more d e t a i l i n F i g u r e 4 where t h e obse rved a v e r a g e v a p o r

t e m p e r a t u r e , p r e s s u r e , and h e a t f l u x a r e g i v e n . The p a r t i a l

p r e s s u r e of t h e a i r i n t h e main room was d e r i v e d from a mass

b a l a n c e on t h e a i r i n t h e t o t a l v e s s e l , based on t h e t empera -

t u r e and p r e s s u r e s i n t h e v a r i o u s r e g i o n s . I t was assumed

t h a t t h e a i r was i n i t i a l l y s a t u r a t e d and t h a t a i r from t h e

c o o l e r r e g i o n s of t h e v e s s e l was s a t u r a t e d a t 118 O F . The

p a r t i a l p r e s s u r e shown f o r s team was c a l c u l a t e d by d i f f e r e n c e

* Spraying Systems Company, BeZZwood, IZZinois.

R U N A 7 , 1 S T P E R I O D I N L E T S P R A Y T E M P E R A T U R E = 1 0 2 O F

S P R A Y FLOW = 4 9 gpm

T O T A L P R E S S U R E -

- C

I T E M P E R A T U R E -

E N D OF S P R A Y -

-

H E A T L O S S F R O M - O U T E R S H E L L

A ( M E T E R R D G . )

I 2 0

4 6 8 10

M I N U T E S OF S P R A Y I N G

FIGURE 4 . Con ta inmen t Vapor Temperature and Pressure Response t o S p r a y i n Run A7

and , i n c i d e n t a l l y , f o l l o w s t h e s a t u r a t i o n p r e s s u r e w i t h i n t h e

e x p e c t e d e x p e r i m e n t a l e r r o r of t h e t e m p e r a t u r e of t h e vapor

s p a c e . No s u p e r h e a t i n g of t h e vapor due t o d e s i c c a t i o n of t h e

s t e a m - a i r m i x t u r e by t h e c o l d s p r a y d r o p s c o u l d be o b s e r v e d .

A d e t a i l e d h e a t b a l a n c e h a s n o t been made. The CSE

v e s s e l h a s a h i g h h e a t c a p a c i t y r e l a t i v e t o t h e h e a t c a p a c i t y

of t h e c o n t a i n e d a tmosphere due t o t h e i n a b i l i t y t o s c a l e V/A

r a t i o s and s h e l l t h i c k n e s s i n d e p e n d e n t l y of t h e l i n e a r s i z e .

A s a consequence , t h e h e a t c o n t e n t of s t e e l ( t o t a l w e i g h t

380,000 l b ) i s i m p o r t a n t i n t h e o v e r a l l h e a t b a l a n c e .

Heat exchange i n t h e upper r e g i o n d u r i n g t h e f i r s t s p r a y

p e r i o d of Run A7 was c a l c u l a t e d and i s shown i n Tab le 11.

TABLE 11. Heat Removal from Upper Vapor Space by a Spray

Steam condensed from a tmosphere 4.8 x l o 5 BTU Heat removed from a i r 0 .08 x l o 5 BTU

Excess s team f e e d ove r h e a t l o s s 0.07 x l o 5 BTU

T o t a l Heat Removed from Atmosphere 4 .95 x 10' BTU

The maximum p o s s i b l e h e a t removal c a p a b i l i t y of t h e e n t e r - 5 i n g c o l d s p r a y of 5 . 8 5 x 1 0 BTU was based on an i n i t i a l l i q u i d

t e m p e r a t u r e of 102 O F and a maximum t e m p e r a t u r e r i s e t o t h e con-

t a inmen t a tmosphere t e m p e r a t u r e . Hence, t h e s p r a y r e s u l t e d i n

a h e a t removal from t h e a tmosphere of 85% of t h e maximum p o s -

s i b l e i n s p i t e of t h e p r e s e n c e of t h e i n o r d i n a t e l y m a s s i v e ,

h o t s t e e l s h e l l .

V A R I A T I O N I N G A S P H A S E S P A T I A L C O N C E N T R A T I O N

C o n c e n t r a t i o n V a r i a t i o n s With in t h e Main Room

I n a l l f i v e e x p e r i m e n t s , Maypack C l u s t e r s were hung a t

v a r i o u s l o c a t i o n s t h r o u g h o u t t h e main room a s shown i n T a b l e 1 2

and F i g u r e 5 . A s i n g l e Maypack C l u s t e r was i n s t a l l e d i n b o t h

TABLE 1 2 . L o c a t i o n s of Maypack Clusters Used i n CSE Spray Experiments

Maypack Cluster levat ti on(^) Radius Azimuth ( b ) Number f t f t degrees

5 of Main Room Top dome

Drywell, near top

Drywell, near bottom

Middle room

Bottom room

a . Main deck i s a t - 5 . 5 ft.

b . Zero d e g r e e s is a t c e n t e r of 8 ft e q u i p m e n t a c c e s s e n t r y .

the Middle Room and the Lower Room. As discussed in previous

reports (7939), the concentration within the Main Room was

essentially uniform during times when sprays were not operated.

An indication of the uniformity during spray periods is pos-

sible by comparing the airborne concentrations at different

locations as determined by Maypack sampling during the time

E L E V A T I O N 0 f t E L E V A T I O N + 1 2 f t E L E V A T I O N + 1 2 f t A N D B E L O W A N D A B O V E

( t ) 24 f t

FIGURE 5. Location of Maypack Clusters in CSE

58

sprays were operated. Tables 13 through 16 list the concentra-

tions for the various forms of iodine for Runs A3, A4, A6, and

A7. No samples were taken during spray periods in Run A8.

Table 17 lists the concentration of cesium as determined by

the filters in the Maypacks for these four experiments. The

mean concentrations in the Main Room and attendant standard

deviations are also shown. These tables show the spatial con-

centrations of the various aerosol and gaseous forms to be

essentially uniform during the time that sprays were operating.

Most of the scatter is believed caused by sampling error.

One sampling location, M 05, was located above the spray

manifold and thus sampled the gas in the nonsprayed region.

Except for Run A7, the concentrations measured by this Maypack

were within one standard deviation of the mean values for all

samplers located within the sprayed region. Sample flow con-

trol problems, occasionally encountered in the CSE experiments,

are believed to be the cause of the somewhat high value for

M 05 obtained in Run A7. This belief is substantiated by the

fact that the fairly inert iodine material, methyl iodide,

found on the charcoal bed was also high. The concentration of

methyl iodide should not differ significantly inasmuch as only

a limited amount was removed by the spray.

Table 18 summarizes the ratio of the concentration measured

in a nonsprayed region (M 05) to that in the sprayed region.

The conclusion is that the concentration in the nonsprayed

region was not significantly different during spray periods

than that in the region covered by sprays. This observation

can be compared to 9.4% calculated by Equation (37) for elemen-

tal iodine for conditions of Run A6, where the effective velo-

city between regions was assumed to be 50 ft/min.

TABLE 13. Iodine Concentrations at Various Vessel Locations * - During First Spray Period - CSE Run A3 , I .

3 I

Concen t ra t ion on Maypack Component, mg/m - . . I

( a ) I - - - - -- --

Loca t ion i n Charcoal Charcoal I

I

Main Room F i l t e r S i l v e r Pa2er Bed T o t a l I

-. - - - - - - - - - -- - - -- I

!>lean 1 . 4 5 1 9 . 3 0 .30 1 .04 22 .1

Std Dev 0.263 1 . 3 2 0 .12 0.35 1 . 4 9

( + 13.1%) -- ( + 6.8%) (+_ 39 .0%) - ( + 3 3 . 2 ) ( + 6.6%) - -

I1:idd.le Room

Lower Room

a . R e f e r t o T a b l e 1 2 f o r v e s s e l c o o r d i n a t e s .

TABLE 1 4 . Iod ine Concentra t ions a t Various Vessel Locat ions During F i r s t Spray Per iod - CSE Run A 4

I . . 3 (a

Concentrat i on On Maypack Compconent s , mg/m - - - -- Locat ion i n Charcoal Charcoal Main Room F i l t e r S i l v e r .--- .-E~P-?L- Bed - -- Tot a1

Mean 0.35 0.44 0.16 0.98 1.93

Std Dev 0.21 0.10 0.05 0.20 0.30

(+ 58.5%) ( + - 23.2%) (+ 32.9%) (+ -- 20.4%) (2 15 .2%)

Middle Room . - - - .- -

~ 1 4 0.36 2.26 0.12 0.34 3.08

Lower Zoom --

M15

a. R e f e r to T a b l e 1 2 f o r coordinates. -

TABLE 15. Iodine Concentrations at Various Vessel Locations During First Spray Period - CSE Run A6

3

( a ) Concentra t i on On Maypack Components , mg/m ---

Locat ion i n Charcoal Charcoal Main Room F i l t e r S i l v e r Paper Bed Tot a 1 --

Mean 0 .31 0 .68 0.35 1.29 2.65

S t d Dev 0.09 0.16 0 .06 0.17 0.38

(+ - 28.4%) (+ 23.5%) (+ - 18 .2%) (+ 13 .2%) (_f_ 14 .6%)

Middle Room

Ml4 0.005 0.02 0 .01 0.007 0.17

Lower Room

a. Refer to T a b l e 1 2 for coordinates.

BNWL- 1 2 4 4

e TABLE 16.

. . . Loca t ion i n (a)

Main Room

Iod ine Concent ra t ions a t V a r i o u s Vessel Locations During F i r s t Spray Pe r iod - CSE Run A7

3 - Concentra t i o n On Maypack Component, mg/m -- - -

Charcoal Charcoal F i l t e r S i l v e r --- Paper Bed -- T o t a l

1 . 5 3 2 .90 3.39 1.38 9.20

Mean 1 . 3 3 3.65 3 .50 1 .37 9 .85

Std Dev 0 .31 1 . 0 1 0.77 0 . 5 1 2.38

( + 23.3%) - ( 2 2 7 . 7 % ) ( + 2 2 . 0 % - ( + 3 7 . 3 % ) ( 2 2 4 . 2 % ) -

Middle Room

~ 1 4

Lower Room

M15

a . R e f e r t o TabZe 2 2 f o r c o o r d i n a t e s .

TABLE 17. Cesium Concentrations in Vapor Space at Various Vessel Locations During First Spray Period

Location i n (a)

Main Room

M02

M0 5

Cesium Concentration On F i l t e r s , mg/m 3

A3 - A 4 - A 6 - - A7

Mean 1 .90 0.98 0.45 0.44

S td Dev 0.21 0.08 0.20 0.009

( + - 11.0%) (+ 7.7%) (+ 43.2%) (5 21.3%)

Middle Room --

~ 1 4

Lower Room - -- -. --

M15

a . R e f e r t o T a b l e 1 2 f o r c o o r d i n a t e s .

b . Not A n a l y z e d .

TABLE 18. Comparison of Concentrations in Sprayed and Nonsprayed Regions Within the Main Room

R a t i o o f Concentra t i o n , M05/:4ean Main Room I o d i n e Iod ine

I o d i n e I o d i n e Charcoal Charcoal I o d i n e Cesium F i i t e r .- S i l v e r -- Paper Bed -- - -. Tot a 1 F i l t e r - .- . - -. -

Run A-3 1 - 2 7 1.13 0.92 0.87 1 . 1 2 1 . 1 3

Run A-4 0.49 0.98 1 .16 0 .96 0. 90 0 .92

Run A-6 1 .24 0.97 1 . 0 0 1 . 0 2 1 . 0 2 0.87

Run A-7 1 . 5 6 1 . 6 2 1 . 8 0 i. 66 1 .60 -- 1 .67 .- -- --

Average 1 . 1 4 1 . 19 1.18 1 .16 1.18 1.13

Concentration Variations Between Compartments

Concentration differences between compartments connected

by a relatively small opening are expected to be much greater

than within a single compartment because of the relatively

small convective flow between compartments. Knudsen and

Hilliard (6) and Morrison et al. (40) have discussed intercompart-

ment transport. Reliable predictions are not possible unless

the flow between compartments can be predicted accurately.

The Main Room, Middle Room, and Lower Room acted in the

CSE experiments as three separate compartments connected in

series by relatively small openings in the floors. Tables 13

through 17 show the concentration in the three rooms during

the first spray period. Figure 6 is a graph of C versus t 8

for a typical experiment, Run A6, showing how the concentration

of total iodine builds up in the lower rooms during spray per-

iods. Operation of sprays reduced the concentration differences

faster than had previously been measured in the absence of

sprays in Runs Al, A 2 , and A5. This development is partly

attributable to the more rapid reduction in the main room con-

centration as well as to the increased intercompartment flow

and perhaps to the liquid-gas absorption reversibility.

$ M A I N ROOM A V E R A G E i 1 a

----d MIDDLE R O O M

, - a LOWER R O O M

0 5 0 1 0 0 1 5 0 1 5 5 0 1 6 0 0 1 6 5 0

T I I I E , r n i n

F I G U R E 6. Typical Buildup of Concentration in Lower Rooms

REMOVAL F R O M CONTAINMENT A T M O S P H E R E S BY SPRAYS

Maypack Data Interpretation

McCormack ( 3 2 ) has discussed the CSE Maypack gas sampling

system and the interpretation of results obtained with this

type of sampling system. A brief discussion is included here to acquaint the reader with the basic manipulations performed

on the raw data to obtain the results shown in the following

sections of this report.

Reference to Figure A-5, Appendix, shows passage of the

fission product, a laden mixture of steam and air, through a

series of media in the following sequences:

1. free-floating Teflon ball check valve

2. two glass fiber filters

3. six silver-plated screens

4. one silver membrane

5. 'one thin charcoal-impregnated paper filter

6. a two-in. deep bed of activated charcoal granules.

The fission product simulant materials are removed by one or

more of the individual Maypack components by filtration,

adsorption, or chemical reactions. The decontaminated steam-

air passes through the Maypack and out of the containment

vessel via insulated lines to the flow control station where

the steam is condensed, the pressure reduced, the air dried,

and the flow rate of dry air metered by rotometer. Backup,

refrigerated charcoal traps retain any of the fission product

simulant materials which might leak through the Maypack.

Solenoid valves start and stop the flow through each Maypack.

A record is kept of the pressure and temperature of the steam- air atmosphere entering the Maypack, the pressure at which the '

rotometer operates, and the average rotometer reading.

The actual volume of containment atmosphere sampled is

calculated by Equation (38):

where

3 VS = gas volume sampled at containment conditions, m , 3 R = average rotometer reading, m /min (STP),

tS = time sampled, min,

= correction factor for rotometer pressure, * 1

f = ratio of air volume in containment to standard tem- a perature and pressure. . * *

The ratio, fa, of air volume at containment conditions to that

for which the rotometer is calibrated (32 O F , 14.7 psia), was

calculated by assuming the air entering the Maypack to be

saturated with water vapor and by using Equation (39):

where

Tb = temperature of air entering Maypack, O R ,

P = total pressure in containment vessel, psia,

PS = vapor pressure of water at T b , psia,

Separate radiometric analyses were made of five components

taken from each Maypack:

N, decontamination of Teflon check valve and nose cone,

A, the two fiber glass filters, B, the six silver screens plus the silver membrane,

C, the charcoal paper,

D, the charcoal bed.

Component N, the nose cone and Teflon ball, retained about 1-5% of the total fission product material. For cesium, this

material was added to the filter component result to give total

cesium. Since, for iodine, the material deposited in the nose

probably consisted of a mixture of elemental and particulate-

associated iodine of unknown proportion, it was not added to

either the filter or the silver component analyses but was

included in the total iodine.

Iodine found on the two fiberglass filters was chiefly

associated with particles, but some elemental iodine is known

to plate on the glass fibers. A correction recommended by

McCormack ( 3 2 ) was applied to the filter result to subtract the

estimated amount of elemental iodine deposited, and this same

amount was then added to the amount found on the silver com-

ponents. Results shown in the following sections for elemental

iodine and particulate associated iodine have been corrected in

this manner.

The thin charcoal-impregnated paper, component C, acts as

a buffer between the silver section and the charcoal bed. It

is very efficient for elemental iodine and ensures that the

slight amount of elemental iodine penetrating the silver com-

ponents does not reach the charcoal bed. The component prob-

ably catches trace amounts of heavy organic iodides, but methyl

iodide retention is quite low because of the short exposure

time in passing through the 0.03-in. thickness. McCormack (321

reports that, for the air tests, 1% of the methyl iodide was

retained on component C and, for the 250 O F steam-air atmo-

sphere tests, 3% of the methyl iodide was retained on the

charcoal paper.

The charcoal bed is efficient for methyl iodide at the

sampling conditions used in these experiments. Since all other

forms of iodine are removed by components upstream of the char-

coal bed, component L, is an accurate measure of the methyl

iodide entering the Maypack.

Gamma analyses for each component, corrected for radio-

active decay to a common reference time, were multiplied by

the specific activity of the fission product simulant material

and divided by the volume of gas sampled to give the mass con-

centration in the containment atmosphere as follows:

C = (d/m) (Spec, Activity)

g vs

where

C = concentration in containment atmosphere, g 3

vg/m 9

d/m = radioactivity on a Maypack component,

corrected for radiodecay,

Spec. Activity = pg of stable iodine or cesium per d/m

equilibrated,

Vs = volume of gas sampled at containment 3 temperature and pressure, m .

One Maypack in each cluster was never used and served as

a blank. Some fission product simulant material was always

found on the blanks, due either to slight leakage of the

solenoid valve or breathing through the loose-fitting Teflon

check valve. On the assumption that all Maypacks gained this

much material during nonsampling periods, the average amount

on all the blanks was subtracted from the corresponding com-

ponent of the other Maypacks. This correction was inconse-

quential until gas phase concentrations had been reduced to

~ 0 . 1 % of initial values. It caused large uncertainties in

results at long containment times.

Concurrent Removal by Natural Processes

The objective of these experiments was to measure the

removal by sprays of the several types of fission product

materials, and to relate the observed removal rates to those

that could be expected in other containment systems, especially

t o t h o s e of l a r g e r power r e a c t o r s . Because removal by n a t u r a l

p r o c e s s e s o c c u r r e d c o n c u r r e n t l y w i t h removal by s p r a y d r o p s ,

and because t h e s e two r a t e s do n o t a lways p roceed i n t h e same

r e l a t i v e r a t i o , i t was n e c e s s a r y t o measure e a c h ind .ependent ly

f o r comparison w i t h t h e i r r e s p e c t i v e t h e o r e t i c a l models . A p p l i -

c a t i o n t o c o n d i t i o n s i n a l a r g e power r e a c t o r con ta inmen t s y s -

tem can t h e n be made by i n s e r t i n g t h e p r o p e r v a l u e s of p a r a m e t e r s

t o each model and summing.

Theory f o r removal by n a t u r a l p r o c e s s e s i s o n l y p a r t i a l l y

v e r i f i e d . Fur the rmore , t h e o p e r a t i o n of s p r a y s p r o b a b l y p e r -

t u r b s t h e n a t u r a l removal mechanisms and makes i t d i f f i c u l t t o

p r e d i c t n a t u r a l removal d u r i n g s p r a y p e r i o d s . T h e r e f o r e , f o r

t h e p r e s e n t e x p e r i m e n t s , s p r a y s were o p e r a t e d f o r s h o r t , w e l l -

d e f i n e d p e r i o d s and t h e removal r a t e b e f o r e and a f t e r each

p e r i o d (by n a t u r a l p r o c e s s e s ) was de te rmined by sampl ing . The

d e c r e a s e i n g a s phase c o n c e n t r a t i o n o c c u r r i n g d u r i n g t h e s p r a y

was a t t r i b u t e d t o t h e combined p r o c e s s of removal by

s p r a y d r o p s and removal by n a t u r a l p r o c e s s e s a t t h e a v e r a g e

of t h e r a t e s b e f o r e and a f t e r t h e s p r a y p e r i o d . For example,

i f b o t h p r o c e s s e s a r e f i r s t o r d e r w i t h r e s p e c t t o g a s phase

c o n c e n t r a t i o n ,

where

- 1 A s = removal r a t e c o n s t a n t f o r s p r a y d r o p s , nlin ,

-1 A n = removal r a t e c o n s t a n t f o r n a t u r a l p r o c e s s e s , min ,

and

BNWL- 1244

where

AN1 = removal r a t e c o n s t a n t b e f o r e s p r a y ,

A N 2 = removal r a t e c o n s t a n t a f t e r s p r a y .

E lemen ta l I o d i n e

The t ime dependence of t h e g a s phase c o n c e n t r a t i o n o f e l e -

m e n t a l i o d i n e i n t h e main room i s shown f o r e a c h exper imen t i n

F i g u r e s 7 t h rough 11. The e x p e r i m e n t a l p o i n t s a r e t h e a v e r a g e

v a l u e s of t h e 1 2 Maypack c l u s t e r s l o c a t e d a t v a r i o u s p o s i t i o n s

t h r o u g h o u t t h e main room. P l u s and minus one s t a n d a r d d e v i a -

t i o n from t h e mean i s i n d i c a t e d by t h e h o r i z o n t a l b a r s above

and below each p o i n t . The f i g u r e s show:

The g a s s p a c e t o be w e l l mixed w i t h i n t h e main room ( s m a l l

s t a n d a r d d e v i a t i o n ) . A l a r g e d e c r e a s e i n g a s phase c o n c e n t r a t i o n d u r i n g t h e

f i r s t , s h o r t s p r a y p e r i o d .

Less d e c r e a s e i n g a s phase c o n c e n t r a t i o n w i t h s u b s e q u e n t

s p r a y s a f t e r d e c l i n e i n t h e c o n c e n t r a t i o n t o <1% of

i n i t i a l v a l u e .

Only s m a l l changes d u r i n g r e c i r c u l a t i o n p e r i o d s , and

G r e a t e r u n c e r t a i n t y of r e s u l t s f o r t h e samples t a k e n a f t e r

A l i n e was drawn c o n n e c t i n g p o i n t s o u t s i d e t h e s p r a y p e r -

i o d s and e x t r a p o l a t e d t o s t a r t and s t o p t i m e s of t h e s p r a y p e r -

i o d s . Judgement was used i n d e t e r m i n i n g t h e b e s t f i t of t h e

d a t a . A s t r a i g h t . l i n e was drawn th rough t h e s p r a y p e r i o d con-

n e c t i n g t h e c o n c e n t r a t i o n a t s t a r t and s t o p . The c u r v e s a r e

marked w i t h t h e c o n c e n t r a t i o n h a l f l i v e s , t l I L , b e f o r e , d u r i n g ,

and a f t e r e a c h s p r a y p e r i o d . The h a l f - l i f e i s t h e t ime r e q u i r e d

t o r educe t h e c o n c e n t r a t i o n by a f a c t o r of two. I t i s r e l a t e d

t o t h e removal r a t e c o n s t a n t by

FIGURE 7. Concentration of Elemental Iodine in the Main Room, Run A 3

BNWL- 1244

FIGURE 8 . C o n c e n t r a t i o n o f E l e n e n t a l I o d i n e i n t h e Main Room, gun A 4

0 5 0 1 0 0 1 5 0 200' 1 5 5 0 1 6 0 0 1 6 5 0

T I M E , m i n

F I G U R E 9 . Concentration of Elemental I o d i n e in t h e Main R o o m , Run A6

-

FIGURE 10. Concentration of L i e r r e ~ e a ; HMine in the Main Room, Run A7

0 3 0 8 0 117 1 5 0 18U 2 0 0 2 6 0 300' 1 3 50 1 4 0 0 1 4 4 0 t o 3 3 T I M E , m i n

FIGURE 11. Concentration of Elemental Iodine in the Main Room, Run A8

The observed half-lives obtained in this manner are listed

in Table 19 for each of the five experiments. The half-lives - . *

due to spray only, after correcting for natural process removal

according to Equation (42), are also listed.

Particulate-Associated Iodine

Figures 12 through 16 show the time dependence of particu- . . late-associated iodine in the main room for the five experiments.

. . Two conclusions are evident. The particulate iodine is rapidly

removed at rates roughly equivalent to those for elemental

iodine, and the amount left at later time is either very small

or not detected. Two explanations are possible. The first is

that iodine associated with particles in these experiments is

not a permanent, solid particle, but rather iodine absorbed

reversibly in fog drops. When the gas concentration is depleted

of elemental iodine, the iodine desorbs from the fog drops.

Second, the correction applied to equate the water found on

Maypack filters to particulate iodine might be wrong. Each of

the possibilities is being explored further. In any event,

however, very little particulate iodine remained after the first

two spray periods in these two experiments. Table 20 lists the

observed half-life and those due to spray only.

Iodine on Charcoal Paper

Figures 17 through 21 show the time dependence of the con- I

centration of the iodine retained on the Maypack charcoal paper

for each of the five experiments. As discussed previously, this . is a mixture of several forms of iodine and thus its transport

behavior cannot be discussed in terms of a single species. This *

concentration, included only for the sake of completeness, is

added, of course, to all the other Maypack components to obtain

the total iodine concentration. Table 21 lists the observed 9.

half-lives for the mixture measured by this Maypack component.

Ln

a i-l

m i-l

rl rd -lJ C a,

8 t-i

W

1

p2 h

I l n l L C l

I . I

I

I

l m l m l o l

k dl N m G C < I m c i

P A R T I C U L A T E I O D I N E , R U N A 3

DROP S I Z E : FLOW R A T E : T E M P E R A T U R E :

1 o 3

1 o 2

T H I R D S P R A Y

l o 1

NOT D E T E C T E D

1 o 0 0 4 0 5 0 1 4 0 1 7 0 1 3 3 7 1 4 7 3 1 5 3 3

T I M E , m i n

GURE 12 . C o n c e n t r a t i o n of P a r t i c u l a t e I o d i n e i n t h e Main Roc Run A 3

T I M E , m i n

FIGURE 1 3 . C o n c e n t r a t i o n o f P a r t i c u l a t e I o d i n e i n t h e Main Room, Run A 4

DROP S I Z E : 1 2 1 0 u M M D FLOW R A T E : T E M P E R A T U R E :

N a O H - p H 9 . 5

................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. T H I R D SPRAY ................. ................ ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ ................. ................ .................

NOT D E T E C T E D

0 3 0 40 80 1 1 0 1 5 6 5 1 6 2 5

TIME, m i n

FIGURE 1 4 . C o n c e n t r a t i o n o f P a r t i c u l a t e I o d i n e i n t h e Main Room, Run A6

T I M E , rnin

F I G U R E 15. C o n c e n t r a t i o n o f P a r t i c u l a t e I o d i n e i n t h e Main Room, Run A7

RUN A 8 , P A R T I C U L A T E I O D I N E

DROP S I Z E : 7 7 0 p MMD FLOW R A T E : 5 0 gpnl T E M P E R A T U R E : 2 5 0 OF P R E S S U R E : 5 0 . 7 p s i a S P R A Y A D D I T I V E : 3 0 0 0 p p m B O R O N

N a O H , p H 9 . 5

( 4 t h S P R A Y H A S 1 w t % N a 2 S 2 0 3 A D D E D )

F O U R T H S P R A Y

S P R A Y R C . )

S P R A Y

T E C T E D S E C O N D

0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 1 3 5 0 1 4 0 0

T I M E , r n i n

F I G U R E 16. Concentration of Particulate Iodine in the Main R o o m , Run A8

CO

cd k n n n n o o L n 0 0 0 u

~ V V V V

* C O O C O l

O r . 1

Ln I

A

0 4 0 5 0 1 4 0 170

TIME, m i

IODINE ON A C P A P E R 1 2 1 0 _ M M D

1 2 . 8 gpm

7 7 O F

1 4 . 6 p s i a

3 0 0 0 ppm H 3 B 0 3

NaOH, pH 9 . 5

F I G U R E 17 . C o n c e n t r a t i o n i n Main Room of I o d i n e A s s o c i a t e d w i t h Charcoa l Paper, Run A 3

DROP S I Z E : 1 2 1 0 1: MMD

FLOW R A T E : 4 8 . 8 gpm

T E M P E R A T U R E :

S P R A Y A D D I T I V E : 3 0 0 0 ppm H 3 B 0 3

N a O H , pH 9 . 5

0 4 0 5 0 1 4 0 1 7 0 3 0 0 1 2 0 5 1 2 5 0

T I M E , m i n

F I G U R E 18 . C o n c e n t r a t i o n i n Kain Room of I o 6 i n e A s s o c i a t e d w i t h Charcoal Paper , 2un A 4

1 o 5 I O D I N E ON A C P A P E R

D R O P S I Z E : 1 2 1 0 1. M M D

F L O W R A T E :

T E M P E R A T U R E : 2 5 5 O F

S P R A Y A D D I T I V E : 3 0 0 0 ppm B O R O N

1 C I 4 N a O H , p H 9 . 5

m E \ u!

" l o 3 Z 0 +- + < CT k- Z W 0 Z 0 U

W v, 4:

:: l o 2 ir)

< C7

0,

0

l o 1

1 o O

0 3 0 4 0 8 0 1 1 0 1 5 6 5 1 5 2 5

T I M E , m i n

FIGURE 1 9 . C o n c e n t r a t i o n i n Main Room of I o d i n e A s s o c i a t e d w i t h Charcoa l Paper, Run A 6

l o 5 - - RLlN A 7 I O D I N E ON A C P A P E R - - D R O P S I Z E : 1 2 1 0 L MMD - FLOW R A T E : 4 9 g p m

k- T E M P E R A T U R E : 2 5 0 " F

P R E S S U R E : 5 0 p s i a

S P R A Y A D D I T I V E : 3 0 0 0 ppm B O R O N A S H 3 B O 3 ,

P H = 5 ( F O U R T H S P R A Y H A S 1 w t

- . 0 5 0 1 0 0 1 5 0 1 3 0 0 1 3 5 0 1 4 0 0 1 4 5 0 1 5 0 0

T I M E , m i n

FIGURE 20. Concentration in Main Room of Iodine Associated with Charcoal Paper, Run A7

770 1. M M D

3 0 0 0 p p m B O R O N AS H 3 B 0 3 - pH 9 . 5

( F O U R T H S P R A Y H A S 1 w t ; ; N a 2 S 2 0 3

I N A D D I T I O N )

3 3 T I M E , n i i n A

FIGURE 2 1 . C o n c e n t r a t i o n i n Xa in Room of Iod ine Associated w i t h Charcoal P a p e r , gun A8

rcl 3 I a, 4 rdk n A

a,3 u u z V

blethvl Iodide

The time dependence of methyl iodide concentration in the

gas phase of the main room is given for each experiment in

Figures 22 through 26. The concentration decreased by about

20% by diffusion into the middle and lower rooms. Usually, by

the end of the second spray period, the concentrations in the

three rooms were about equal. Other than for this effect, the

methyl iodide concentration due to operation of the sprays with

either fresh or recirculated alkaline borate solution did not

decrease appreciably.

In experiments A7 and A8, a fourth spray using 1 wt%

Na2S203 added to alkaline borate was made at the end of the

experiment. A definite decrease in methyl iodide concentration was noted in these two cases. Table 22 lists the concentration

half-lives measured and corrected for natural removal processes.

Total Iodine

?'he total iodine concentration was obtained by summing the

iodine forms found on all five of the Maypack components. Beha-

vior of the total iodine concentration, although understandable

only in terms of its constituent parts, is of interest fo'r its

graphical display as affected by the sprays, Such plots are

shown in Figures 27 through 31. Before the first spray, the

iodine was largely in the form of elemental iodine (see Table 9).

Therefore, its behavior matched that of elemental iodine quite

closely. At later times, the iodine was mostly methyl iodide

and the total iodine concentration behavior reflected this fact.

Table 23 lists the observed and corrected concentration half-

lives for the five experiments.

......... ......... l o 4 -- ...... ... ......... ......... ... ......... ... ......... ... - ......... ... ... ......... RUN A 3 ......... ... M E T H Y L I OD1 DE ......... ... ......... ... ......... ... - ......... ... ......... ... ......... ... ......... ... ......... ... DROP S I ZE : - ......... ... ......... ... 1 2 1 0 ;? MMD ......... ... ......... ... ......... ... ......... ... ......... ... - ......... ......... ... ... ......... ... FLOW R A T E : ......... ... 1 2 . 8 gprn ......... ... ......... ... ......... ... ......... ... ......... ... - ......... ... ... .::..:..:::. ... ......... ... ... ......... T E M P E R A T U R E : 7 7 O F ......... ... ......... ... ......... ... ......... ... ......... ... ......... ... - ... .,,,,,,,,, ... ......... ... ......... P R E S S U R E : 1 4 . 6 p s i a ... ......... ... ......... ... ... ... : 3 0 0 0 p p m H 3 B 0 3

N a O H , p H 9 . 5

. .

................... ................... ................... - . . ................... .................... ........................ .............

,-4

t-

rY

T H I R D W

........................ ............... ........................ ............... .................... ................... ....................... .................... ................ .................... ................... .................... ................... ................... ......................... ................... . . . . . . . . . . . . . . . ................... .................... ................... .................... .................... ................... ................... .................... ................... .......................... ................................. ................... .................... ......................... .............. ................... .................... ................... .................... .......................... ............. ....................... ................ ................... .................... ..................... .................. ..................... .................. ................... ..................... ................... ................... .................... ................... ................... .................... ...................... ................ ...................... ................ ................... ................... ................... .................... ................... .................. ................... ................... ................... ................... .................... .................. ................... ................... ................... ................... ................... S P R A Y ................... ................... ................... .................... .................. ...................... ................ ................... ( R E C I R C . ) .................... ................... .................. ................... ................... ..................... ................. ................... ................... ................... ................... ................... ..................... ................... ................. ................... ................... ................... ...................

......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... I # J )

................... ..................... ................... ................. ......................... ............. .................... ................... ................... .................... ................... .................... .................... ................... ................... .................... ................... .................... ................... ........................ ................... ................ .................... ................... ..................... .................. ................... .................... ................... .................... .................... .................... ................... ................... .................... ....................... ................ ................... .................... ................... .................... ..................... .................. .................... ................... ................... .................... ................... ................... ................... .................... ................... ..................... ................... ................... .................... ................... .................... ................... .................... ................... ................... .................... ................... .................... ................... .................... ................... ........................ ................... . . . . . . . . . . . . . . . . ................... .................... ................... .................... ................... .................... ................... .................... ................... ................... ................... ................... ................... .................... ................... .................. ................... ................... .................... .................. ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ................... ...................................... ................... ................... ................... ................... ................... ................... ................... ................... ...................

0 4 0 5 0 1 4 0 1 7 0 1 3 3 7 1 4 7 3 1 5 3 3

T I M E , m i n

FIGURE 22. Concentration of Methyl Iodide in the Main Room, Run A3

D R O P S I Z E : 1 2 1 0 . M M D

F L O W R A T E :


S P R A Y A D D I T I V E : 3 0 0 0 ppm H3B03

N a O H , pH 9 . 5

F I R S T S P R A Y

0 4 0 5 0 1 4 0 1 7 0 30.0 1 2 0 5 1 2 5 0

T I M E , m i n

FIGURE 23. Concentration of Methyl Iodide in the Main Room, Run A4

M E T H Y L I OD1 D E

1 2 1 0 .. M M D

49 gpm 255 O F

44 p s i a

3 0 0 0 p p m BORON

NaOH, pH 9.5

3 3 0 4 9 8G 1 1 3 1565

T I M E , m < n

FIGURE 24. Concentration of Methyl IodiGe in the iqain Room, Run A6

R U N A 7 M E T H Y L I O D I D E

D R O P S I Z E : 1 2 1 0 ,J MMD

F L O W R A T E : 4 9 gpm

T E M P E R A T U R E : 2 5 0 O F

P R E S S U R E : 5 0 p s i a -

S P R A Y A D D I T I V E : 3 0 0 0 ppm B O R O N A S

H 3 B 0 3 , p H = 5

( F O U R T H S P R A Y H A S

1 w t i N a 2 S 2 0 3

0 5 0 1 0 0 1 3 0 0 1 3 5 0 1 4 0 0 1 4 5 0 1 5 0 0

T I M E , m i n

FIGURE 25. Concentration of Methyl Iodide in the Main R o o m , Run A7

T I M E , m i n

R U N A 8 M E T H Y L I O D I D E

D R O P S I Z E : 7 7 0 , M M D

F L O W R A T E : 5 0 gP"-

T E M P E R A T U R E : 2 5 0 O F

P R E S S U R E : 5 0 p s i a


N a O H , p H = 9 . 5

( F O U R T H S P R A Y H A S 1 w t %

N a 2 S 2 0 3 A D D E D )

FIGURE 2 6 . C o n c e n t r a t i o n of Methyl I o d i d e i n t h e Main Room, Run A 8

T I M E , m i n

FIGURE 27. Total Iodine Concentration in the Main Room, Run A 3

T I M E , ra in

FIGURE 28. Total Iodine Concentration in the Main Roon, Run A4

T I M E , r n i n

T O T A L I O D I N E

D R O P S I Z E : 1 2 1 0 p M M D

F L O W R A T E :


P R E S S U R E :


N a O H , pH 9 . 5

FIGURE 29. Total Iodine Concentration in the Main Room, Run A6

0 3 0 40 8 0 1 1 0 1 3 2 3 1 3 8 3 1 4 4 3 1 4 9 3

T I M E , m i n

FIGURE 30. Total Iooine Concentration in the Main Room, Run A7

0 5 0 100 2 0 0 250 1350 1400

T I M E , rn in

FIGURE 31. Total Iodine Concentration in the Main Room, Run A8

h I I I I

I l l

. ri J1 0 M

Cesium

The time dependence of the gas phase cesium concentration

in the main room is shown for each experiment in Figures 32

through 36. Standard deviations of experimental points are

small, except for late in the experiments when most of the

cesium has been removed. Removal rate during the first spray

was quite high in all of the experiments, but succeeding sprays

were less effective. This result probably reflects more effi-

cient removal of the larger cesium particles, and the leaving

behind of smaller, less easily removed particles. A discussion

of particle size measurements is given in a later section of

this report. Table 24 lists the measured concentration half-

lives and also those corrected for natural removal processes.

Uranium

The time dependence of the gas phase concentration of

uranium-associated particles in the main room is shown in

Figures 37 through 41 for each experiment. That removal was

not quite as fast as for cesium suggests the uranium particles

to be of a smaller size distribution than cesium. However,

the uranium concentration was depleted by a factor of about

100 by 40 min of spraying, plus the natural process removal

for all runs except A3, the low flow rate experiment.

Table 25 lists the concentration half-lives for uranium mea-

sured for each experiment and also that due to sprays alone.

0 4 0 5 0 1 4 0 1 7 0 1 3 3 7

T I M E , m i n

FIGURE 32. Cesium Concentration in the Main Roon, Run A 3

FIGURE 33. Cesium Concentration in the Main Room, Run A4

R U N A 6

D R O P S I Z E :

FLOW R A T E :

C E S I U M

1 2 1 0 11 M M D

4 9 gpm

2 5 5 " F

4 4 p s i a

I V E : 3 0 0 0 p p m B O R O N ,

N a O H , pH 9 . 5

. . 0 5 0 1 0 0 1 5 0 1 5 5 0 1 6 0 0 1 6 5 0

T I M E , m i n


FIGURE 3

0 3 0 4 0 8 0 1 1 0 1 3 2 3 1 3 8 3 1 4 4 3 1 4 9 3 I J

T I M E , m i n

5. Cesium Concentration in the Main Room, Run A7 -

T I M E . r n i n


a

a

cd

k

OM

OO

On

a

ri

ri

R U N A 3 , U R A N I U M

D R O P S I Z E : 1 2 1 0 , M M D

F L O W R A T E : 1 2 . 8 gpm

T E M P E R A T U R E : 7 7 " F

P R E S S U R E : 1 4 . 6 p s i a

S P R A Y A D D I T I V E : 3 0 0 0 p p m H 3 B 0 3

NaOH, p H 9 . 5

t1 ,2= 6 0 m i n

, , 0 5 0 1 0 0 1 5 0 1 4 5 0 1 5 0 0 1 5 5 0

T I M E . m i n

FIGURE 37. Uranium Concentration in the Main Room, Run A3

U R A N I U M

D R O P S I Z E : 1 2 1 0 MMD

FLOW R A T E :


P R E S S U R E :

S P R A Y A D D I T I V E : 3 3 0 0 p p m H 3 B 0 3

N a O H , p H 9 . 5

0 40 5 0 1 4 0 1 7 0 3 0 0 1 2 0 5 1 2 5 0

T I M E , m i n


D R O P S I Z E : 1 2 1 0 ,, MMD

F L O K R A T E :


P R E S S U R E :

S P R A Y A D D I T I V E : 3 0 0 0 p p m B O R O N

NaOH, p 3 9 . 5

0 3 0 4 0 80 1 1 9 1565 1 6 2 5 *

T I M E , m i n

FIGURE 39. Uranium Concentration in the Main Room, Run A6 -

DROP S I Z E : 1 2 1 0 4 M M D FLOW RATE :

0 3 0 4 0 8 0 1 1 0 1 3 2 3 1 3 8 3 1 4 4 3 1 4 9 3

T I M E , m i t i

FIGURE 40. Uranium Concentration in the Main R o o m , Run A7

11 5

l o 4

= 30 m i r


0

a

I0

h

)r

nO

rn

O

tdk

0

On

n

a,

l

LC

- o a

a

L.

m

A

4-

-

A

5

co ~

n

I a,

*n

.

cdk

UN

On

I

a)?

N

-4

0a

I

cn M

u I

hh

h

hh

cd

rd hcd hcd

cd

h

M

d

cdh

kd

aF:

ma

I I

II

I

~r

f~

b~

I

I

IM

IN

I I

I

C O N C E N T R A T I O N I N L I Q U I D PHASES

?he data presented in the previous section clearly show

most of the fission product simulant materials studied to have

vanished quite rapidly from the gas phase during early spray

periods. The disappearance rates can be obtained from curves

of gas phase concentration versus time. That these rates can

be used to verify mass transport theory will be shown in a

later section of this report. A more direct method of verify-

ing the theory of transfer between gas and liquid phases is to

measure the rates of transfer to the liquid drops and wall

film. This measurement has proved difficult to make accurately

in the CSE vessels because of the large, complex geometry and

resultant excessive lag time in obtaining liquid samples when

dealing with the very rapid transfer rates involved. Never-

theless, measurements were made and, despite great uncertainty

during spray periods, these measurements of mass added to the

liquid phases substantiate the theory and confirm that iodine

and particles were indeed transferred to the liquid at approx-

imately the rates indicated by loss from the gas phase.

Three types of measurements made on the liquid phase were

(I) the concentration and volume in vessel sumps, (2) the con-

centration in the liquid spray drops caught in flight by fun-

nels located at several locations in the main room, and (3) the

concentration and flow rate down the outer containment vessel

wall.

Collection in Vessel Sumps

Most of the liquid sprayed through the nozzles fell through

the atmosphere in the main room and either settled on the main

deck or fell to the bottom of the drywell vessel. A small frac-

tion impinged on the vertical walls at an elevation about 3 ft

below the nozzles. Table 10 gives the ciistribution between

these three locations. The liquid entering the drywell fell

directly into the drywell sump. The volume in the drywell

sump thus increased abruptly when spraying started, and stopped

increasing abruptly when spraying stopped. Flow of the liquid

falling onto the deck, however, was directed over the horizontal

surface and drained through the two 4-ft diam openings into the

lower rooms before entering the main containment vessel sump.

A significant delay resulting, at times, in unaccounted for material balances of up to 3000 liters thus was caused. The

liquid continued to drain into the containment vessel sump for

about 90 min after the sprays were stopped. A typical water

balance is presented in Table 26 for Run A7.

The concentrations of iodine and cesium in the two sumps

are plotted versus time for each experiment in Figures 42

through 46. Also shown are the observed liquid volumes in the

sumps. It Is possible to make mass balances as a function of

time for the i~dine and cesium by combining the information

obtained from these graphs with the gas phase data from Fig-

ures 2 7 through 36. Typical results for iodine are shown in

Figures 47 and 48 for Run A 3 and A 7 , respectively. The reader

will recall t n a t Run A3 was made with room temperature air,

while Run A7 was with steam at a nominal temperature of 250 O F .

Similar curves are presented for cesium in Figures 49 and 50.

In these figures, the difference between the mass released into

containment (from Tables 6 and 7) and that accounted for by

summing the airborne mass and mass in the vessel sumps is shown

as a b r ~ k e ~ l line labeled "unaccounted for." Material reacting

with the p ~ ~ n t on structural surfaces, and material in liquid

pools not yet dra~ned into the sumps are probably represented.

The unaccounted for cesium balances followed closely the water

balances, as can be seen by comparing Figures 49 and 50 with

Table 26, and thus indicates that very little cesium reacted

with the paint. Unaccounted for iodine, however, exceeded the

unaccounted for water at all times, thus suggesting that a sig-

nificant fr~i;ion of the iodine was reacted with the paint.

TABLE 2 6 . T y p i c a l Water Balance--Run A7

Time, min

Volume in Sumps, R

DW CV Total

12 5 700 8 2 5

Cumulative Cumulative Total to Steam Feed, Spray Added, Accounted for, Unaccounted

E R R for, R Remarks

Start Aerosol Release

Start 1st Spray End 1st Spray

Start 2nd Spray End 2nd Spray

Start Recirculation

End Recirculation

Start 4th Spray End 4th Spray

A D R Y W E L L SUMP

/--

/- ----

T I M E , m i n

FIGURE 42. Liquid Volunes and Concentrations in Vessel Sumps, Run A 3

ZIGURE 43. Liquid Volumes and Concentrations in Vessel Sumps, Zun A4

T I M E , n l i r i

FIGURE 44. Lic;uid Volumes an6 Concentrations in Vessel Sumps, 2un A6

R U N A 7 C V D R Y W E L L

IODINE 0 CESIUM V O L U M E - - -----

. -

0 5 0 100 1300 1350 1400 1450 1500

T I F I E , r n i n

F I G U R E 45 . Liquid Volumes and Concentrations in Vessel Sumps, Run A7

0 25 50 75 100 125 150 2 0 0 250 1350 1400

T I M E , n ~ i n

FIGURE 46. Liquid Volumes and Concentrations in Vessel Sumps Versus Time--Run A8

T O T A L I O D I N E M A S S = 7 5 . 8 i 3 . 8 g

U N A C C O U N T E D

0 40 5 0 1 0 0 1 4 0 1 7 0 200

T I M E , rn in

FIGURE 47. Iodine Distribution Versus Time--Run A3

- ,

0 5 0 1 0 0 1 5 0 1 3 0 0

T I M E , m i n

FIGURE 48. Iodine Distribution Versus Time--Run A7

100 200

T I M E , rn in

F IGURE 49. Cesium Distribution Versus Tine- -Run A 3

0 5 0 1 0 0 150 1300

T I M E , rn in

FIGURE 50. Cesium Distribution Versus Time--Run A7

These conclusions are substantiated by the overall mass

balances shown in Tables 6 and 7 and by deposition coupon

data, tabulated in a later section.

Concentration in Spray Drops

An attempt was made to measure the concentration of

iodine and cesium in the spray drops at several elevations and

radii. Funnels intercepted the drops in flight and the col-

lected liquid was drained to collection pots outside the con-

tainment vessel. The pots were emptied manually every one or

two minutes during early spray periods. One disadvantage of

this method was the lag time, introduced between the time of

interception by the funnel and the time the liquid was drawn

off from the pot, was estimated to be 2.6 + 0.4 min for all funnel locations. In addition, contamination from previous,

higher concentration liquid was inevitable.

Figures 51 through 54 show the concentration in the spray

liquid as a function of time. Sampling problems were encount-

ered in Run A6 and data for this experiment are not shown.

The curves should be adjusted to earlier times by the previ-

ously referenced 2.6-min lag time.

These data are difficult to interpret, not only because

of sampling inadequacies, but because the relative fractions

of the various iodine forms and particle size were changing

rapidly with time. However, they do show that iodine and

cesium were collected by the spray drops in about the right

amount compared to that lost by the gas phase. For example,

in Run A4, integration of the iodine mass in the spray drops

during the first period gives 29 g picked up by the spray,

compared with 24 g lost by the gas phase. This result is con-

sidered an adequate agreement considering the uncertainty in

the spray liquid measurement.

T I M E , rn in

FIGURE 5 3 . Iodine and Cesium Concentration in Spray Drops-- Run A7

FOURTH S P R A Y

FIGURE 54. Iodine and Cesium Concentration in Spray Drops-- 3

Run A 8

The d a t a o b t a i n e d from a n a l y s e s of t h e l i q u i d c o l l e c t e d

by t h e f u n n e l s a r e n o t s u f f i c i e n t l y d e f i n i t i v e t o make a con-

c l u s i o n c o n c e r n i n g t h e c o n c e n t r a t i o n i n d r o p s a s a f u n c t i o n of

f a l l h e i g h t . Improvements i n sampl ing t e c h n i q u e s a r e a v a i l a b l e

f o r f u t u r e t e s t s .

C o n c e n t r a t i o n i n t h e Wall Fi lm

A t r o u g h r u n n i n g c o m p l e t e l y around t h e o u t e r v e s s e l w a l l

c o l l e c t e d t h e s p r a y i n t e r c e p t i n g t h e v e r t i c a l w a l l s . The f l o w

r a t e of s o l u t i o n from t h i s t r o u g h was m e t e r e d , sampled p e r i o d -

i c a l l y , and r e t u r n e d t o t h e main con ta inmen t v e s s e l sump.

Tab le 10 l i s t s t h e f l o w r a t e s f o r each e x p e r i m e n t . F i g u r e s 5 5

th rough 58 show t h e c o n c e n t r a t i o n s of i o d i n e and cesium i n t h e

l i q u i d a s a f u n c t i o n of t i m e . I n t e g r a t i o n of t h e p r o d u c t of

t h e c o n c e n t r a t i o n and f l o w r a t e g i v e s t h e mass of i o d i n e and

cesium l e a v i n g t h e w a l l f i l m . During t h e f i r s t p e r i o d , t h e

mass of i o d i n e and cesium l e a v i n g t h e w a l l f i l m was a b o u t t h e

same f r a c t i o n of t o t a l removed by s p r a y s a s t h e volume f r a c t i o n

i n t e r c e p t e d by t h e w a l l s . T h i s f i n d i n g s u g g e s t s t h a t most of

t h e i o d i n e and cesium was c o l l e c t e d by s p r a y d r o p s i n t h e g a s

b e f o r e impinging on t h e w a l l s .

During t h e second s p r a y p e r i o d , ces ium b e h a v i o r was s i m i -

l a r t o t h a t i n t h e f i r s t p e r i o d , b u t i o d i n e mass i n t h e w a l l

f i l m was n e a r l y e q u a l t o t h e i o d i n e c a p t u r e d by d r o p s and t h a t

f a l l i n g t o t h e deck o r d r y w e l l . T h i s b e h a v i o r c o u l d be

e x p l a i n e d by i o d i n e d e s o r b i n g from t h e p a i n t , o r t o t h e f a c t

t h a t o r g a n i c forms of i o d i n e p r e v a i l e d d u r i n g t h e second p e r -

i o d , and removal a t t h e w a l l c o u l d , t h e r e f o r e , be r e l a t i v e l y

more i m p o r t a n t t h a n f o r e l e m e n t a l i o d i n e .

T a b l e 2 7 g i v e s a comparison of t h e t o t a l measured g a i n by

l i q u i d s t r e a m s w i t h t h a t l o s t from t h e g a s phase f o r Run A 4 .

The amount p i c k e d up by l i q u i d s exceeded t h a t l o s t by t h e g a s

i n e v e r y c a s e , b u t t h e agreement i s w i t h i n e x p e r i m e n t a l e r r o r

and s u b s t a n t i a t e s t h a t t h e i o d i n e and cesium e n t e r e d t h e s p r a y

l i q u i d a t t h e r a t e s i n d i c a t e d b y Maypack a n a l y s e s of t h e g a s

p h a s e . 135

T I M E , m i n

FIGURE 55. Iodine and Cesium Concentration in Wall ~ i l m , Run A3

m

I 7

[I) a

0

[I)

N

SG

io

.- 0

Tl-

E

.ti 7

-I-'

. . [I)

c\ a,

m

U

R A D I U S , r / R

D I S T A N C E B E L O W N O Z Z L E I N F E E T 8

S P R A Y R A T E

4 0 5 0 1 4 0 1 5 2 1 6 4 1 7 6 1 2 3 5 1 2 0 5 1 2 5 0

T I M E , m i n

FIGURE 52. Iodine and Cesium Concentration in Spray Drops-- Run A4

T I M E , m i n

F I G U R E 5 6 . I o d i n e and Cesium C o n c e n t r a t i o n i n W a l l F i l m , Xun A 4

0 C E S I U M

N 9 T E : T I M E S C A L E C t I A N G E

T I M E , r n i n

FIGURE 57. Iodine and Cesium Concentration in Wall Film, Run A7

R U N A8

A I O D I N E

0 C E S I U N

N O T E : T I V E S C A L E C H A N G E AT t = 50

t l i i = 8.5 m i n

t 1 / 2 = 1 2 m i

(r 2 5 ; i r r' 556 800 1050 1300

T I P ' E . r r i n

F I G U R E 58 . W a l l Trough C o n c e n t r a t i o n Versus Time--Run A 8

TABLE 27. Comparison of Iodine and Cesium Mass Gained by Liquids with Loss by Gas--Run A4

Is t Spray 2nd Spray

Iodine Cesium Iodine Cesium

Gain by spray drops, g 29 3.0 0.21 0.70

Gain by wall film, g 3.8 0.39 0.15 0.051

Total gain by liquids, g 32.8 3.4 0.36 0.75

Loss by gas, g 2 4 2 . 7 0 . 3 4 0 . 3 5

gain by liquids Ratio, loss by gas

spray drops wall film

Final Equilibrium

Not much change in the concentration of any ok the gas-

borne materials occurred during the third recirculation period

in any of the experiments. This lack of change may indicate

that an equilibrium between gas and liquid was reached prior

to recirculation. In a few cases, the slight concentration

increase during recirculation was considered compatible with

an equilibrium condition. Re-exposure of the more concentrated

liquid in the lower sump to the dilute gas atmosphere could

increase the gas concentration by desorption or formation of

small liquid particles.

Table 28 lists the total concentration reduction factors

resulting from the combined processes of spraying and natural

effects from time zero to the end of the recirculation period.

Because the amount of liquid and spray plus steam condensate

probably affects the overall decontamination, the ratio of gas

to liquid volume at the end of the recirculation period is also

Ti-

I v

XX

XX

X

XX

XX

XX

X

t-

.N

N\

Dr

nT

i-

N

'31 v

shown. Data for Run A3 are included, but the reader should * .. recall that a fresh water spray instead of recirculation was - . used in the test.

- * Table 28 shows that elemental iodine and particulate-

associated iodine concentrations were reduced by a factor of

about 1000, material on the charcoal paper by a factor of about

10, methyl iodide by a factor of about 2, cesium by about 1000,

and uranium by about 500. Total iodine concentration was

reduced by a factor of 15 in the air tests, but by about 200

in the steam-air atmosphere tests. The higher reduction in

steam atmospheres was caused by the greater removal of methyl

iodide at the higher temperatures.

P A R T I C L E S I Z E M E A S U R E M E N T

The size distribution of particles in the containment

atmosphere was measured in all the experiments except Run A3.

Measurements for Run A4 were obtained by pulling a sample of

the containment atmosphere (room temperature air) through a

short tube and a Cassella* type impactor. Measurements in the

other experiments involving pressurized steam-air atmospheres

were made by inserting a Scientific Advancesk* type inertial

impactor directly into the vessel atmosphere. The impactor

was preheated to ~ 3 0 0 O F before insertion to prevent steam con-

densation in the instrument. Stage cut-off limits for unit

density particles are 0.25, 0.5, 1.0, 2.0, 4.0, and 8 and

greater microns for the Scientific Advances impactor.

Size data for the four experiments are given in Table 29.

In general, the aerodynamic mass median diameter for both

cesium and uranium was reduced by the action of the sprays.

The absolute values of the data presented in Table 28 are

probably biased toward the low side because of the sampling

* C . F . CasseZZa & Co. , L t d . , London, Eng land .

* * S c i e n t i f i c Advances , I n c . , CoZumbus, Oh io .

method u s e d . The p a r t i c l e s a r e b e l i e v e d t o be a s s o c i a t e d w i t h

condensed w a t e r i n t h e form of f o g d r o p l e t s ( s e e s e c t i o n on

v i s u a l o b s e r v a t i o n s ) . The e q u i l i b r i u m s i z e o f l i q u i d f o g d r o p s

i s v e r y dependen t on t h e r e l a t i v e h u m i d i t y of t h e a i r s u r r o u n d -

i n g t h e d r o p s . Use of a p r e h e a t e d s a m p l e r , t o g e t h e r w i t h p r e s -

s u r e d r o p a c r o s s t h e o r i f i c e s of t h e i m p a c t o r , p r o b a b l y c a u s e d

w a t e r t o e v a p o r a t e f rom t h e d r o p s d u r i n g s a m p l i n g , w i t h s m a l l e r

s i z e s b e i n g i n d i c a t e d t h a n a c t u a l l y e x i s t e d i n t h e c o n t a i n m e n t

env i ronmen t . Improvements i n p a r t i c l e s i z e s amp l ing t e c h n i q u e s

a r e b e i n g d e v e l o p e d .

TABLE 2 9 . P a r t i c l e S i z e Ana lyses - CSE Spray T e s t s

Aerodynamic P a r t i c l e D i a m e t e r , ( a ) IIIMD, p

Run ~ 4 ~ ~ ) Run ~ 6 " ) Run ~7 Run ~8

B e f o r e 1st Sp ray 0 . 9 1 . 6 0 . 5 1 . 0 2 . 0 1 . 8 0 . 5 0 . 8

A f t e r 1st Sp ray 0 . 5 0 . 7 0 . 4 0 . 9 0 . 3 0 . 6 0 . 6 0 . 9

-

a . Diameter r e l a t i v e t o s e t t l i n g v e l o c i t y o f a u n i t d e n s i t y s p h e r i c a l p a r t i c l e .

b . C a s s e l l a Impac tor ; sampled o u t s i d e t h e con ta inmen t v e s s e l .

c. S c i e n t i f i c Advances I n e r t i a l Impac tor ; sampled w i t h i n con- t a i n m e n t v e s s e 2 .

D E P O S I T I O N COUPON D A T A

Coupons of v a r i o u s t y p e s o f m a t e r i a l s were su spended a t

d i f f e r e n t l o c a t i o n s t h r o u g h o u t t h e g a s s p a c e t o measure d e p o s i -

t i o n on noncondens ing s u r f a c e s . Some were a l s o p r e s s e d a g a i n s t

t h e o u t e r w a l l t o measure d e p o s i t i o n c o n c u r r e n t w i t h h e a t t r a n s -

f e r . The l a t t e r coupons e x t e n d e d a b o u t 1 / 1 6 i n . o u t f rom t h e

v e s s e l w a l l , s o i t i s d o u b t f u l t h a t c o n d e n s a t e from h i g h e r e l e -

v a t i o n s r a n o v e r them. But s i n c e t h e y were a t t a c h e d t o t h e

c o l d e r w a l l , c o n d e n s a t e d i d form on them. The coupons were

2.5-in. diam washers, 1/16-in. thick, and with a 17/32-in.

hole in the center. All coupons were installed before the

test and removed after the vessel had been purged. All were

oriented vertically and exposed to the spray liquids.

Table 30 lists the average iodine deposition remaining on

five types of materials exposed to noncondensing conditions.

The standard deviations from the mean are shown also. Similar

data for cesium are given in Table 31. The relative affinity

of each of the five materials for iodine and cesium can be

inferred by examining the depositions for a single experiment.

In air (Runs A3 and A4), the retention of both iodine and

cesium decreased in the order of silver, Phenoline 302,

Amercoat 66, carbon steel, and SS-304. In steam-air atmospheres,

the order for iodine was carbon steel, Phenoline 302,

Amercoat 66, silver, and SS-304. In steam-air, cesium followed

the order of Phenoline 302, Amercoat 66, carbon steel, silver,

and SS-304.

The variation for a given material from test to test

reflects the differences in test conditions (atmosphere, tem-

perature, initial gas phase concentration, spray additives).

For example, the silver coupons in Kuns A7 and A8 retained

very little iodine compared to the other tests. The sodium

thiosulfate sprays used in these two tests apparently removed

most of the iodine deposited earlier in the run.

The deposition on small coupons should not be expected to

represent accurately the deposition on large surface areas.

Other investigators (41,42) have shown that orientation, heat

transfer, and location affect deposition rates. Gas boundary

layer thicknesses are dependent on length along the surface

and angle of inclination of the surface to the gas stream. (43)

However, the data obtained from coupons were extrapolated to

the entire CSE vessel area for a check on material balance

calculations. Since >99% of the interior surfaces in the CSE

were c o a t e d w i t h P h e n o l i n e 302 p a i n t , t h e d a t a u s e d f o r t h i s

m a t e r i a l were p r o r a t e d be tween n o n c o n d e n s i n g a n d h e a t t r a n s f e r

s u r f a c e a s shown i n T a b l e 32.

TABLE 3 0 . I o d i n e D e p o s i t i o n o n V a r i o u s Noncondensing S u r f a c e s

D e p o s i t i o n a t End o f E x p e r i m e n t , pg/crn2 and 1 o ( % )

S u r f a c e M a t e r i a l ( a ) Run A3 Run A 4 Run A6 Run A7 Run A8

S i l v e r ( b ) 109 6 6 . 2 8 . 5 8 0 . 0 8 5 0 . 1 3 5 '2 6 % '20 % +56% 554% 563%

Carbon S t e e l (b 1 5 . 3 8 0 .284 1 9 . 8 1 7 . 0 1 7 . 3 +14.8-30% '17% 235% +48 %

S t a i n l e s s S t e e l 304 ( b ) 0 .052 0 . 0 4 1 0 . 5 2 0 . 0 8 8 0 .050 (ASTbI A 2 4 0 - 6 3) '110% '170% '275% '35% +66%

P h e n o l i n e 302") 8 . 1 4 2 . 5 5 1 5 . 3 2 2 . 3 1 3 . 4 t 4 5 % +30 % '25% +28% t 4 0 %

Amercoat 66 (b , d l 1 . 0 5 0 . 4 9 0 . 2 5 1 6 . 9 9 . 8 8 2 1 8 % '16% + 2 0 % +18% ?38%

a . 2 2 / 2 i n . diam, 1 / 1 6 i n . t h i c k , 1 7 / 3 2 i n . c e n t e r h o l e . T o t a l s u r f a c e = 6 4 cm2.

b . A v e r a g e o f 11 l o c a t i o n s i n ma in room.

c . C o a t i n g manudpac tured b y C a r b o Z i n e C o . , S t . L o u i s , Mo. A v e r a g e o f 2 2 Z o c a t i o n s .

d . C o a t i n g m a n u f a c t u r e d b y Amercoa t C o r p . , S o u t h G a t e , C a l i f .

TABLE 3 1 . C e s i u m D e p o s i t i o n o n V a r i o u s N o n c o n d e n s i n g S u r f a c e s

D e p o s i t i o n a t E n d o f E x p e r i m e n t , p g / c m 2 a n d 1 o (%)

S u r f a c e Mater ia l ( a ) Run A3 Run A4 Run A6 Run A7 R u n A8

S i l v e r (b 0 . 0 1 1 8 0 . 0 0 9 5 0 . 0 0 3 9 0 . 0 0 1 3 4 0 . 0 0 0 6 2 5 6 9 % 2 6 5 % + 5 7 % 2 3 5 % 2 6 2 %

C a r b o n S t e e l (b ) 0 . 0 0 4 2 0 . 0 0 2 0 0 . 0 0 3 4 0 . 0 0 6 3 7 0 . 0 0 4 9 + 4 1 % + 3 2 % + 9 6 % 2 8 0 % 2 3 4 %

S t a i n l e s s S t e e l 3 0 4 (b ) 0 . 0 0 1 6 0 . 0 0 2 6 0 . 0 0 0 0 3 0 . 0 0 0 5 6 0 . 0 0 0 0 2 (ASTM A 2 4 0 - 6 3 ) + 7 6 % + 5 7 % + 6 8 % 2 8 4 % 2 6 1 %

P h e n o l i n e 3 0 2 0 . 0 0 2 5 0 . 0 0 3 5 0 . 0 0 4 2 0 . 0 0 7 9 0 . 0 0 6 6 2 5 2 % + 3 6 % ? 4 0 % 5 1 3 % 2 5 5 %

A m e r c o a t 6 6 (b , d ) 0 . 0 0 3 9 0 . 0 0 5 4 0 . 0 6 3 0 . 0 1 0 0 0 . 0 0 1 8 2 3 3 % 24 3 % 5 4 5 % 2 3 7 % + 4 5 %

a . 2 1 / 2 i n . d iam, 1 /16 i n . t h i c k , 17 /32 i n . c e n t e r h o l e . T o t a l s u r f a c e = 6 4 em2.

b . Avera ge o f 1 1 Z o c a t i o n s i n main room.

c . C o a t i n g m a n u f a c t u r e d by CarboZine Co. , S t . L o u i s , No. Average of 22 l o c a t i o n s .

d . C o a t i n g m a n u f a c t u r e d by Amercoat Corp . , S o u t h G a t e , C a l i f .

TABLE 3 2 . D e p o s i t i o n n V e s s e l S u r f a c e s I n f e r r e d f r o m C o u p o n Data ?a

F r a c t i o n o f I n j e c t e d Mass o n V e s s e l S u r f a c e s N o n h e a t

I n j e c t & ? Mass, H e a t T r a s e r g S u r f ace ?cf S u r f a c e S u r f a c e

T r a n s f e t d )

T o t a l V e s s e l

Run I C s I C s I Cs I Cs

- -

a . P h e n o l i n e 302 coupons .

b . From T a b l e s 6 and 7 .

c . 327 m 2 i n C S E main room.

d . 242 m" i n Cse main room.

1 4 6

The two methods of e s t i m a t i n g t h e f r a c t i o n a l mass d e p o s i t e d

and r e t a i n e d on v e s s e l s u r f a c e s a r e compared i n Tab le 3 3 . The

agreement i s s u r p r i s i n g l y good and s u b s t a n t i a t e s a s r e a s o n a b l e

t h e v a l u e s o b t a i n e d from m a t e r i a l b a l a n c e s r e p o r t e d i n t h e

f i r s t p a r t of t h i s s e c t i o n .

TABLE 3 3 . Comparison of D e p o s i t i o n by Coupon Data w i t h M a t e r i a l Ba lance C a l c u l a t i o n s

F r a c t i o n of I n j e c t e d Mass on V e s s e l S u r f a c e s I o d i n e Cesium

Coupon M a t e r i a l Coupon M a t e r i a l Run Data ( a ) Balance (b) Data (a ) Balance (c ) -

a . F r o m T a b l e 3 3 .

b . F r o m T a b l e 6 .

c . F r o m T a b l e 7 .

C O M P A R I S O N O F T H E O R Y W I T H E X P E R I M E N T 1 -

E L E M E N T A L I O D I N E

" Initial S ~ r a v Washout Kate

An important measure of the effectiveness of a spray for

removing elemental iodine is the initial washout rate. This

rate is important from a hazards analysis viewpoint because

the greatest leakage hazard for iodine would exist initially.

From a model verification viewpoint, the initial washout rate

is most amenable to simple analysis because factors such as

inter-room transport, reversible adsorption phenomena, back-

pressure of dissolved iodine, and changes in thermodynamic con-

ditions are relatively unimportant initially. For long spray

periods, these factors may have a controlling influence on the

gas phase concentration.

The washout of elemental iodine due to operation of sprays

was calculated by subtracting from the measured washout rate,

the washout rate observed when the spray was not operating.

The purpose of this correction was to permit separation of the

washout due to spray drops alone and that occurring at wall

surfaces. This method of correction is not strictly correct

because the wall film absorption would be influenced by the

increased liquid flow rate over the wall surfaces during the

spray period. Better methods for accounting for wall film

absorption are currently being explored. In Table 34, the

spray washout rates for elemental iodine are shown along with

the removal rates observed before and after the spray period.

TABLE 34. Observed Washout of Elemental Iodine During First Spray Period

tl/23 Gas Concentration Half-Life, min X s Due to Washout Rate

Before During After Spray Constant Run 1st Spray 1st Spray 1st Spray Alone (min-l) - A3 60 min 5.0 min 46 min 5.5 min 0.126

A4 65 1.4 Indeterminate 1.4 0.495

A6 12 1.9 260 2.1 0.330

A7 16.5 2.0 49 2.2 0.315

A8 17 0.64 200 0.64 1.08

The washout rate for the spray alone was compared to pre-

dictions based on Equation (16). This equation is based on

the following simplifying assumptions: (1) puff release of

iodine, (2) atmosphere is well mixed, (3) the backpressure of

dissolved iodine at the gas-liquid interface is negligible,

(4) inter-room transport is negligible, and (5) the thermo-

dynamic and flow conditions are constant. These assumptions

appear reasonable for the first spray period in the CSE

experiments. The release of iodine to the containment vessel

was completed some 30-40 min prior to spray initiation and,

hence, there was no iodine injection source term. The concen-

tration levels were relatively high so that desorption from

surfaces would not constitute a major iodine source term. The

first relatively short spray periods would prevent lowering of

the concentration to a level where desorption, and inter-room

transport could act as significant source terms.

The mixing within the containment vessel has been assessed

during each CSE run by comparing concentrations measured at

each of the sampling positions. These measurements indicate

that, within a few minutes after aerosol injection, the atmo-

sphere may be considered well mixed.

Backpressure of iodine from spray drops is minimized by

use of a fresh spray solution. Absorption of iodine by a drop

as it falls causes the liquid concentration to increase from

zero at its formation point to a level of about 1500 times the

gas concentration at the termination of its exposure as a drop.

This concentration level is only a few percent of the equili-

brium saturation concentration and, hence, backpressure of the

dissolved iodine would be expected to be minor. However, the

liquid phase iodine concentration admittedly is large compared

to that which could be absorbed without chemical reaction, and

the foregoing conclusion that iodine backpressure is minor is

based on the assumption that the liquid phase chemical reac-

tions are very fast compared to the drop fall times.

Temperature and pressure within the containment vessel

decrease due to the use of fresh spray. For the temperatures

and pressure changes encountered in the first spray periods,

the change in absorption rate for a gas phase limited process

is predicted to be small.

Theoretically, calculation of the drop exposure time for

each drop size increment of the spray should allow for initial

velocity. Example calculations using the drop size spectrum

do not yield results greatly different than those using a mean

of the distribution and assuming terminal velocity for the entire fall distance.

An estimate of the effect of distribution of drop sizes

was made by calculating the spray washout incrementally and

assuming terminal settling velocity for the whole fall height.

The drop size distribution used in this calculation was that

supplied by the manufacturer of the spray nozzles.* This dis-

tribution is reproduced in Figure 59.

* Spraying Systems Co., BelZuood, Illinois.

-

-

-

A - 2 0 N O Z Z L E 6 - 3 N O Z Z L E - A P = 4 0 p s i

- -

- D A T A S U P P L I E D B Y - S P R A Y I N G S Y S T E M S CO.

- B E L L W O O D , I L L I N O I S

- R O O M C O N D I T I O N S

-

-

- I 1 1 I I 1 1 1 1 I I I I r I 1 1

1 0 0 0

D R O P D I A M E T E R , p

FIGURE 59. Drop Size Distribution for Sprays Used in CSE

--. The mean drop size found to represent the whole spray was L -

very nearly equal to the surface mean diameter of 980 P . The

surface mean diameter was computed from the mass median diam- .- eter of 1210 p by using the log-probability distribution as

modified to account for a maximum drop size by Mugele and

Evans. (44)

?'he influence of initial velocity on reducing the absorp-

* . tion compared to that for terminal velocity was estimated by

calculating the velocity as a function of distance from the I, nozzle. The initial velocity at the nozzle was taken to equal

to the flow rate divided by the orifice cross section area. It

r was assumed that all drops were directed downward. The results

of this calculation are shown in Figure 60 where the net absorp-

tion is compared to an estimate based on terminal settling

velocity. The decrease in absorption when initial velocity is

accounted for is less than the decrease in exposure time because

of increased mass transfer coefficients at the higher velocities

Figure 60 shows that the effect of initial velocity will not be

of great importance for containment vessels with fall heights

greater than 30 ft. A summary of predicted values for falling

drops for five CSE spray tests is given in Table 35.

* The last two columns of Table 35 represent the washout rate

constarlts (is = ---- Oa6") predicted first on the basis of the mass t

1 / 2 median diameter and terminal velocity, and then on the basis of

the surface mean diameter to account for initial velocity. For

the surface mean diameter, initial velocity was accounted for

first by calculating the washout coefficient, As, based upon an 1

assumption of terminal velocity for the entire fall height. L

Ishis A S ' bilsed on terminal velocity, was then multiplied by a 4

factor to account for the effect of changing velocity on the

exposure time and for the mass transfer coefficient. The inte-

grated effect of initial velocity on drop absorption limited

Run -

TABLE 35 . P r e d i c t e d Drop Washout C o n s t a n t s f o r CSE Spray T e s t s

Predicted As, min - 1

Drop Size, 11 Spray Fall Chamber 6Fh k 6F kg (f ) Rate, Hei ht, Volu a) g MMD ( SMD(~) ft3/min ft$c) ft 3T2j v v d v v d t------ -g- -

a . Mass m e d i a n d i a m e t e r .

b . S u r f a c e mean d i a m e t e r .

c . A v e r a g e e f f e c t i v e f a l l h e i g h t .

d . Main room.

e . . U s i n g MMD and t e r m i n a l v e l o c i t y .

f. U s i n g SMD and c o r r e c t i n g f o r i n i t i a l d r o p v e l o c i t y .

by gas phase resistance is shown in Figure 60. For a drop size

of 980 y , the correction factor was 0.91, and for 650 11 drops,

the correction factor was 0.92. Theoretically, the latter

method of calculation should provide the best estimate.

A comparison of the predicted washout rate constants shown in Table 35 with the measured decay constants reported in

Table 34 is presented in Figure 61. Perfect agreement between

theory and experiment would be represented by a 45' line passing

through the origin. As expected, the predicted washout rate

based on the mass median diameter is somewhat lower than that

obtained from the surface mean diameter. The difference in the

predictions is not great, however, and a firm judgment of the

type of mean to be used cannot be drawn from the data shown in

Figure 6 1 .

-

0 U S I N G MMD A N D T E R M I N A L V E L O C I T Y 9

- -!!-L U S I N G S M D A N D C O R R E C T I O N F O R I N I T I A L

g D R O P V E L O C I T Y

-

-

-

F R O M E Q U A T I O N ( 1 6 )

-

-

FIGURE 61. Comparison of Experimental Initial Washout f

of Elemental Iodine with Drop Absorption Model

Perhaps the most striking feature of Figure 61 is the

excellent agreement between predicted and measured washout

rates, The agreement is within the limits of accuracy of the

prediction ( ~ 2 0 % ) when potential inaccuracies in drop size,

diffusivities, settling velocities, and mass transfer coeffi-

cients Ere considered.

The agreement between the observed washout rate and that

predicted from the simple model suggests that iodine back-

pressure at the drop surface and inter-room transport are small

factors initially. The first of these factors could not be

true unless a rapid chemical reaction should cause dissolved

iodine to react as shown in Equation (3) and, hence, we must

conclude that even at low values of pH, dissolved iodine quickly

reacrs to form species of low volatility.

Eauilibrium Gas Phase Concentration

'ihe initial washout rate for elemental iodine continued

until the iodine concentration had decreased to about 1% of its

initial v ~ l u e . In all five experiments, the gas phase concen-

tration decreased more slowly at longer times. This behavior

can be explained by the possibility that (I) small source terms

?rc::r ,*c :-.:i;~e a negligible early effect but become more important

as the concentration decreases, or (2) the material determined 1- - - .,, \ I a l - ~ i ~ i L . . analysis to be elemental iodine is actually a mix-

ture of elemental iodine and one or more other iodine forms not

absorbc'.! effectively by fresh sprays. Several sources were

present in the CSE tests. Sprays were not initiated until 20

or 3 d min after iodine release was completed. During this per-

iod, 50 to 75% of the iodine was deposited on structural sur-

faces by natural transfer processes. If these processes were

reversible, some of the iodine would be released back into the

gas phase after the iodine concentration in the gas phase was

reduced hy spray washout. Another source of iodine is diffu-

sion from thc middle room.

BNWL-1244 A

Before terminating these experiments, the liquid in the * - '

sumps was recirculated through the spray nozzles to equili- . brate the gas and liquid phases. The approach to equilibrium .

-. would be similar to that described by Equation (26). The time

dependency during the course of extended periods will disappear,

and the equilibrium concentration will be

where

C = gas phase solute concentration at equilibrium, g e

C = gas phase solute concentration at time zero, go L = liquid volume,

V = gas volume,

H = equilibrium distribution coefficient.

Equation (43) is not strictly valid because it neglects irre-

versible reaction of the solute (iodine) with paint or other

structural materials and assumes gas volume, V, to be constant,

i.e., that the volume occupied by the spray liquid is neglig-

ible compared to that occupied by gas. About one-fourth to

one-half of the iodine released into the CSE containment

atmosphere reacted irreversibly with the paint (see Table 8).

Thus Equation (43) could be wrong by a factor of 2.

Partition coefficients calculated according to Equa-

tion (43) are listed in Table 36. Run A3 data are omitted

because fresh water was used in that test instead of recircu-

lated sump liquid. Partition coefficients were also calculated

using Equation (4), which defines H as P

where CLe is the concentration of all forms of the solute in

the liquid at equilibrium. Values obtained by Equation (4)

are also listed in Table 36. Good agreement between values

of H calculated by the two methods is evident.

TABLE 36. Partition Coefficients for Elemental Iodine

- Run A4 Run A6 Run A7 Run A8

Final V/L 100 60 7 0 8 0

Time of Sampling, min 1300 1630 1500 260

H, predicted, Ref (45) 6.7 x 10 3.2 x 10 2.5 x lo1 2.3 x lo5

The partition coefficients predicted from Eggleton's (45)

theory are also listed in Table 36. This theory accounts for

the following chemical reactions:

K1 I2 (gas-phase) = I2 (aqueous)

where the K's are the equilibrium constants. The numerical

values of the equilibrium constants were those suggested by

Eggleton. (45) These constants were evaluated at 225 OF by the

Arrhenius extrapolation of data listed for 25 " C and 100 OC.

The measured values of partition coefficient do not appear

to be as dependent on the temperature and pH of the water as

was predicted, particularly for Run A7, where boric acid at pH

of 5 was found to react with I 2 as well as when the solution

was made basic by addition of NaOH. This disagreement likely

arises because all of the important chemical reactions observed

have not been accounted for properly in the theory. The parti-

tion coefficients measured in these studies are of the order of

magnitude reported in other experiments. (6,33,39,46)

Dose Reduction Factors

If a containment vessel leaks at a constant rate and fis-

sion products are not plated out in the leak paths, the rate

of fission product emitted to the environs is directly propor-

tional to the concentration in the contained gas.

where

M L = mass leaked in time t ,

FL = fractional leak rate of contained gas,

V = contained gas space volume,

C = instantaneous average concentration in gas space. g

The dose reduction factor (DRF) is the ratio of mass which

would leak if the concentration was invariant with time at its

initial value, Co' divided by the mass which will actually leak

while the concentration is decreasing:

DRF = Co

(48)

For cases where the gas concentration decreases exponentially

as in Equation (49),

the dose reduction factor can be expressed as

DRF = X t

1 - e - X t

where t is the time for which the reduction factor applies.

However, as discussed in this report, the concentration does

not decrease exponentially forever, but approaches an equili-

brium at about C /Co = 0.01. Therefore, Equation (48) should g

be solved numerically. As an example, if AS = 1 min-' until

Cg/Co = 0.01, after which the concentration remains constant,

the DRF for the initial 2-hr period would be 55 and the 24-hr

DRF would be 94. These estimates are probably low because

(1) release probably would not be instantaneous and (2) the

concentration would probably continue to decrease below

0.01 Co, as it did in the present tests.

METHYL I O D I D E

Methyl iodide is only slightly soluble in water and reacts

relatively slowly in solution. Thus, the transfer rate to a

liquid would be controlled by mass transfer within the liquid

phase. For relatively slow chemical reaction, methyl iodide

absorption by wall films is highly important because of the

large interfacial areas and the long exposure times as compared

to spray drops. For a spray rate of 50 gpm, and with drops of

1200-p diam, the drop surface area is calculated to be 600 ft.

The wetted wall area within the main room of the CSE vessel is

about 10 times this value.

Methyl Iodide Reaction Rates

Analysis of absorption with chemical reaction shows that,

for first order chemical reactions, the absorption coefficient

is enhanced by a factor of

where

kgk = liquid phase mass transfer coefficient with chemical

reaction

for small values of kte. Thus, appreciable enhancement will

not occur unless kte is of the order of unity or larger. Esti-

mates of the reaction rates for the solutions used in CSE were

made on the basis of data tabulated in Reference (18). Evalua-

tion of the reaction rates at a temperature of 2 4 8 O F required

extrapolation of data obtained at lower temperature and, for

this reason, the pseudo-first-order reaction rates listed in

Table 37 are of unknown accuracy.

TABLE 37. Estimated Reaction Rate Constants of Spray Solutions with Methyl 1odide (a)

Solution k(~20) - 1 OH-) - 1 ( ~ a ~ ~ ~ 0 ~ ) k(total) sec-1 - 1 Composition sec sec sec

H3B03 + NaOH,

PH = 9.5 3.3 1.7 x lo-' o 3.3

H 3 B 0 3 , NaOH,

Drop contact times in the CSE vessel are of the order of one

to 10 sec. For the wall film, contact times are of the order

of minutes. The data presented in Table 37 indicate that

enhanced drop absorption per pass would occur only for the

thiosulfate spray. For the wall film, some enhancement due to

reaction would be expected for all of the spray solution listed

in Table 37. A modest rate of removal of methyl iodide by reaction with the H20 molecule would be expected in long term

tests because of the relatively large liquid volumes and the

long times for reaction.

Removal of Methyl Iodide by Nonreactive Sprays

The first three spray periods in each run employed water

without sodium thiosulfate. The reaction rate of methyl iodide

with the spray solution was slow and, as a first approximation,

the washout by these sprays may be considered as absorption

with no chemical reaction. An upper limit to the washout rate

with a nonreactive solution may be obtained by assuming that

all spray liquid reaches equilibrium with the gas phase, and

is then removed from the chamber. A material balance on the gas phase gives the gas phase concentration as a function of

time:

where

Ls = volume of fresh solution sprayed.

If the liquid in the pools accumulating in the bottom of spray

chamber is exposed to the gas, dissolved methyl iodide would

re-equilibrate with the gas phase. A lower limit of absorp-

tion by once-through nonreactive sprays may be estimated by

assuming all the liquid in the vessel to be at instantaneous

equilibrium with the gas phase. For this case, the gas phase

concentration would be given by

where

V = initial containment gas volume, go

L = initial volume of liquid in containment. 0

The changes in methyl iodide concentration measured for

fresh water sprays in the CSE vessel are compared to predic-

tions based on Equations (52) and (53) in Table 38. The par-

tition coefficients listed are from data reported in

Reference (47) . The results shown in Table 38 demonstrate that essentially

no removal of methyl iodide would be expected for nonreactive

water sprays. This indication is due to the low partition - coefficient for methyl iodide in water. Most of the measured

washout fractions would be close to the predicted zero where

allowance is made for diffusion into the middle and lower rooms.

From Maypack samples taken within these rooms, it was observed

that these rooms became mixed with the main containment volume

during the second spray period. The first spray period was not

of sufficient duration to cause effective inter-room mixing of

methyl iodide and, for simplicity, it was assumed that no mix-

ing had occurred during the first spray period, but that mixing

was complete for the second and third spray periods.

The observed concentration reduction factors are generally t

less than unity, thus indicating that some methyl iodide removal

may be occurring. However, the rate is too slow to be deter-

mined from the measurements reported in Table 38, and it is con- L

cluded that the washout rate of methyl iodide by basic borate

solution is slow. 4

0

0

rl

0

0

rl

a3

m

0

I+

rl

m

M

N

0

0

a

M

t-. d

0

0

4

0

0

I+

N

m

0

rl

rl

t-. d

N

M

0

N

M

d

03

4

Removal of Methyl Iodide by Reactive Sprays

In Runs A7 and A8, sprays of 1 wt% sodium thiosulfate

were included near the end of the experiments to assess the

washout of methyl iodide by a reactive spray. Fresh spray

solution was used for the entire 50-min spray periods. The

temperature decreased appreciably over the duration of the run

and, since the calculated reaction rates are highly dependent

on temperature, a stepwise estimation of the cumulative wash-

out was carried out. Temperatures, calculated reaction rates,

and estimated partition coefficients at 10-min intervals are

listed in Table 39.

TABLE 39. Estimated Reaction Rates and Partition Coefficients for Thiosulfate Sprays

Time from Beg inning of Spray,

min

Reaction Rate (a) sec-1

Partition (b ) Coefficient

Run A7 Run A8

232 245

221.5 228

211 212

202 197

193.5 184

187 174.5

Run A7

2.69

1.91

1.28

0.904

0.628

0.468

Run A8

4.42

2.30

1.28

0.729

0.418

0.278

Run A7 Run A8

1.10 1.09

1.12 1.11

1.13 1.13

1.16 1.18

1.19 1.24

1.23 1.30

a . E s t i m a t e d from d a t a r e v i e w e d i n R e f e r e n c e ( 1 8 ) .

b . E s t i m a t e d from d a t a p r e s e n t e d i n R e f e r e n c e ( 4 7 ) .

The effective average temperature for washout of methyl iodide

by the thiosu.lfate sprays was 210 O F for Run A7 and 212 O F for

Run A8. The washout rate was calculated for these average

temperatures by simple models for drops and wall films. For

the drops, calculation of absorption assumed that the drops

fell at terminal velocity for the entire fall height, that the

I .

r . drops were at all times well mixed, and that the mass median

. - diameter adequately represented the drop size distribution. The mass transfer coefficient for this model is given by:

- .. (kgA) drops = FH (1 + kt,).

This expression will likely overestimate drop absorption but,

since drop absorption does not appear to govern the overall

absorption rate, this overestimate is not of great practical

importance.

The wall film was assumed to be laminar, of uniform

thickness, and that all surfaces within the upper room of the

containment vessel were wet by a film similar to that calcu-

lated for the cylindrical walls of the vessel. Inlet effects

related to film absorption were neglected. For this simple

model, the mass transfer coefficient, for a film of thickness

6, is:

(kgA)wall w JkDQ tanh

The film thickness, 6, was predicted from the measured liquid

flow rate on the vertical cylindrical walls of the vessel.

The simple laminar flow theory of Nusselt ( 4 8 ) gives for the

film thickness:

where

r = volumetric rate of flow per unit width of wall, and

v = kinematic viscosity of liquid.

The methyl iodide absorption rates predicted for the drop and

wall film models described in the foregoing are compared to

the measured washout rates in Table 40.

TABLE 4 0 . Methyl I o d i d e A b s o r p t i o n by T h i o s u l f a t e S p r a y s i n CSE

Drop P r e d i c t e d Wall Film P r e d i c t e d P r e d i c t e d Measured Flow t Flow nriapf :' t l 2 f o r i O v e r a l l Washout R a t e , R a t e , Wa 1 F i l m , t 1 ~ 2 , t 1 [ 2 ,

Run gas/min min ga l /min min mln mln

The d a t a p r e s e n t e d i n T a b l e 40 show t h e p r e d i c t e d washout h a l f -

t ime t o be i n good agreement w i t h t h e measured v a l u e s . A l s o ,

t h e c a l c u l a t i o n s i n d i c a t e t h a t t h e w a l l f i l m a b s o r p t i o n i s

r e l a t i v e l y more i m p o r t a n t t h a n a b s o r p t i o n by d r o p s , f o r methyl

i o d i d e . T h i s i n d i c a t i o n i s e x p e c t e d , s i n c e w e t t e d w a l l a r e a s

expose a b o u t 6000 f t 2 o f i n t e r f a c e a s compared t o 600 f t 2 of

i n t e r f a c i a l a r e a c a l c u l a t e d f o r t h e f a l l i n g d r o p s . T h i s l a r g e

c o n t r i b u t i o n by t h e w a l l f i l m would occur o n l y f o r a b s o r p t i o n

i n which l i q u i d r e s i s t a n c e domina tes . For g a s phase l i m i t e d

t r a n s f e r , d r o p a b s o r p t i o n would be c o n t r o l l i n g due t o t h e much

h i g h e r g a s phase mass t r a n s f e r c o e f f i c i e n t t o f a l l i n g d r o p s ,

compared t o t h e w a l l s u r f a c e s .

The obse rved washout r a t e s shown i n Tab le 40 a r e i n a g r e e -

ment w i t h t h e washout r a t e p r e d i c t e d on t h e b a s i s of s m a l l e r

s c a l e s p r a y s t u d i e s u s i n g hydrazene i n p l a c e of sodium

t h i o s u l f a t e . (18)

A E R O S O L P A R T I C L E S

A e r o s o l p a r t i c l e s may be c a p t u r e d by s u r f a c e s w i t h i n a con-

t a i n m e n t v e s s e l o r by s p r a y d r o p s d u r i n g a s p r a y p e r i o d . In

t h i s r e p o r t , we w i l l e s t i m a t e t h e washout due t o d r o p s a l o n e

and compare t h i s e s t i m a t e d washout w i t h t h a t o b t a i n e d e x p e r i -

m e n t a l l y . The e x p e r i m e n t a l washout r a t e s were o b t a i n e d by s u b -

t r a c t i n g from t h e t o t a l washout r a t e t h e a v e r a g e of t h e washout

r a t e s due t o n a t u r a l p r o c e s s e s b e f o r e and a f t e r t h e s p r a y

p e r i o d .

The t a r g e t e f f i c i e n c i e s f o r Brownian d i f f u s i o n , i n e r t i a l

i m p a c t i o n , i n t e r c e p t i o n , and d i f f u s i o p h o r e s i s were c a l c u l a t e d

f o r d r o p s of d i a m e t e r 500, 1000, and 2000 y u s i n g t h e methods

d i s c u s s e d i n t h e t h e o r y s e c t i o n of t h i s r e p o r t (Equa t ion 28

th rough 3 4 ) . An example of t h e s e c a l c u l a t i o n s i s shown i n

F i g u r e 6 2 where t h e e q u i v a l e n t t a r g e t e f f i c i e n c y i s shown f o r

p a r t i c l e s i z e s r a n g i n g i n d i a m e t e r from 0.001 t o 10 p. These

c a l c u l a t i o n s were made f o r a s t e a m - a i r a tmosphere a t 2 5 0 OF

s a t u r a t e d w i t h a i r i n i t i a l l y a t a p a r t i a l p r e s s u r e of 0.97 atm

and a t 80 O F . Spray i n l e t t e m p e r a t u r e of 120 O F and a f a l l

h e i g h t of 33.8 f t were assumed. The r e s u l t f o r u n i t d e n s i t y

s p h e r e s i s shown i n F i g u r e 62.

P a r t i c l e d e n s i t y e n t e r s o n l y f o r t h e impac t ion mechanism.

Hence, t h e c a l c u l a t i o n f o r u n i t d e n s i t y s p h e r e s would a p p l y

f o r more dense p a r t i c l e s w i t h a d e n s i t y c o r r e c t i o n f o r i n e r t i a l

impac t ion .

P a r t i c l e s i z e s were measured by means of a c a s c a d e impac-

t o r . S i n c e t h e impactor measures aerodynamic d i a m e t e r , a

d e n s i t y must be used t o c a l c u l a t e g e o m e t r i c a l s i z e s . For

ces ium, a d e n s i t y of u n i t y was assumed s i n c e t h e cesium p a r -

t i c l e s would l i k e l y be p r e s e n t a s s o l u t i o n d r o p l e t s . For 3 uranium, a d e n s i t y of 7 . 2 g/cm , t h e same a s f o r o x i d e U308,

was assumed. T h i s i s p r o b a b l y h i g h e r t h a n t h e a c t u a l d e n s i t y

because uranium o x i d e a e r o s o l p a r t i c l e s c o n s i s t of agglomer-

a t e d s m a l l e r p a r t i c l e s . The p r e d i c t e d and measured washout

r a t e s a r e compared f o r cesium i n Tab le 41 and f o r uranium i n

Tab le 42.

Comparison of t h e p r e d i c t e d and measured washout r a t e s

shows t h e measured p a r t i c l e removal r a t e t o be s i g n i f i c a n t l y

l a r g e r t h a n t h e p r e d i c t e d washout r a t e . T h i s l a r g e r t h a n p r e -

d i c t e d removal r a t e i m p l i e s t h a t e i t h e r (1) one of t h e c a p t u r e

mechanisms h a s been u n d e r e s t i m a t e d , o r (2) i n c o r r e c t p a r t i c l e

s i z e d a t a was used . The most l i k e l y e x p l a n a t i o n i s t h a t

I M P A C T I O N ( U N I T D E N S I T Y P A R T I C L E )

- 2 0 0 0 p D R O P

D I F F U S I O N

D I F F U S I O P H O R E S I S ( 3 3 . 8 f t F A L L , 1 5 0 O F A T )

2 0 0 0 u D R O P

1 0 0 0 u D R O P

I N T E R C E P T I O N

- 2 0 0 0 u D R O P

I I I -

P A R T I C L E D I A M E T E R , p

FIGURE 6 2 . Predicted P a r t i c l e Col lec t ion Eff ic iency f c r Fa l l ing Drops

TABLE 4 1 . Washout of cesium P a r t i c l e s by CSE Sprays

5 / 2 3 min MMD T a r g e t E f f e c t T a r g e t Washout

Nominal Spray P a r t i c l e MMD Measured from Measured E f f e c t from P r e d i c t e d Run Temp, OF P e r i o d Diam, 11 S p r a y , p t l / 2 9 min

-- Washout P r e d i c t e d T a r g e t E f f e c t

TABLE 4 2 . Washout of Uranium Oxide Aerosol by CSE Sprays

5 / 2 9 min

MMD T a r g e t E f f e c t T a r g e t Washout Nominal Spray P a r t i c l e MMD Measured from Measured E f f e c t from P r e d i c t e d

Run Temp, O F P e r i o d Diam, p S p r a y , p t l / 2 9 min Washout P r e d i c t e d T a r g e t E f f e c t

inertial impaction has been underestimated. This mechanism

would account for the observed washout for particle diameters

of 2-4 p. Since appreciable pressure changes occur within a

cascade impactor, it is possible that evaporation of water from

the sampled particles reduced their size.

The theoretical calculations indicate that diffusiophoresis

acts as a removal mechanism of importance for particles of any

size. For the fresh spray periods of Runs A6, 7, and 8, cal- ,

culations indicate that a minimum particle washout half-time

of about 30 min for 50 gpm spray flow would be maintained. All L

of the measured removal rates exceed that expected for diffusio-

phoresis alone. I

Because the washout rate (and therefore the concentration

in the gas space) of particles is very dependent on the parti-

cle size distribution, behavior of particulate matter after a

LOCA in a large power reactor cannot be confidently predicted

unless the particle size is accurately known. However, assum-

ing the particles in the present experiments to be typical of

those present in the postaccident containment atmosphere, a

2-hr dose reduction factor (DRF) of 20 for cesium and about

10 for uranium could be expected.

ACKNOWLEDGEMENTS

Successful performance of these large-scale experiments - would not have been possible without the coordinated teamwork

of the entire staff of the Reactor Safeguards Experiments

Section. The authors wish to acknowledge that much of the

hard work was done by many individuals whose names do not

appear but whose cooperation was invaluable. The authors also * . acknowledge the guidance and consultations which helped in

planning the experiments. Speci.al thanks are due - . Dr. J. G. Knudsen, Oregon State University; Tom H. Row, Oak

Ridge National Laboratory; and our sponsor, the Research and

Development Branch-Nuclear Safety, Reactor Development and

Technology, U.S. Atomic Energy Commission. D. H. Stevens,

Douglas United Nuclear, Inc., correlated the data reported for

heat transfer.

N O M E N C L A T U R E

a = radius

A = surface area

AF = floor area (horizontal projection)

AW = effective wall surface area

B = particle mobility

BIZ = exchange coefficient for inter-room transport

C = mass concentration in gas phase g

C Q = mass concentration in liquid phase

C = heat capacity P d = drop diameter

d = diameter of spherical particle P dl = diameter of water molecule

d2 = diameter of air molecule

De = liquid phase diffusivity

D = diffusion coefficient for particle P

Dv = gas phase diffusivity

E = total collection efficiency of drop

EBD = drop target efficiency for Brownian diffusion

ED = effective target efficiency for diffusiophoresis

E~~~ = drop target efficiency for interception

F = volumetric generation rate of spray drops

f = fraction of contained volume not washed by sprays

fA = ratio of air volume in containment to volume at

standard temperature and pressure

fR = correction factor for rotameter reading

g = acceleration due to gravity

G = generation rate of FP (or simulant) mass

Gr = Grashov number

h = fall height of drop

He = gas-liquid partition coefficient for a single species

H = gas-liquid partition coefficient, including fast

chemical reaction

AHc = latent heat of condensation (per mole)

k = first order reaction rate constant, or Boltzmann

constant

k = natural convection mass transfer coefficient C

k = gas phase mass transfer coefficient g

k g = liquid phase mass transfer coefficient

k = mass transfer coefficient due to condensing steam S

K = overall mass transfer coefficient g

K1, K 2 = equilibrium constants for chemical reactions

L = volume of liquid held in sump, or length of vertical

surface

L F = volumetric flow rate of liquid wall film

Lo = volume of liquid in containment initially

LS = volume of fresh liquid sprayed

m = mass of particle

M = molecular weight

n = mass flux of steam to wall S

ps = vapor pressure of water

P = total pressure in vessel

q = mass absorbed per unit area

Q = volumetric flow of gas between regions, or mass

absorbed during drop fall time

R = gas constant, or rotameter reading

Re = Reynolds number

RG = gas phase reaction rate

Sc = Schmidt number

t = time

te = exposure time of drops to atmosphere

tS = sample duration time

5 / 2 = concentration half-life

T = absolute temperature

AT = temperature difference

u = gas velocity at gas-liquid interface max

v = terminal settling velocity of drop or particle g

vs = gas sample volume (containment conditions)

vw = wall deposition velocity for particle

V = free gas volume in containment vessel

V = initial containment gas volume go

VWF = volume of liquid held up on wall as film

x = distance from surface of film

y = distance measured along film

G R E E K SYMBOLS

y1 = mole fraction of water vapor

y2 = mole fraction of air

I' = wall flow rate per unit width of perimeter

6 = film thickness

X = first order removal rate constant

XN = removal rate constant due to natural processes

= removal rate constant due to spray drops

v = kinematic viscosity

p = density

a = slip factor 12

SUBSCRIPTS

b = b u l k phase

g = g a s phase

i = i n t e r f a c e o r s p e c i e s t y p e

R = l i q u i d phase

o = i n i t i a l c o n d i t i o n

2 = second chamber

R E F E R E N C E S

H . N . C u l v e r . " E f f e c t o f Eng inee red ~ a f e ~ u a r d s o n R e a c t o r S i t i n g , " N u c l e a r S a f e t y , v o l . 7 , n o . 3 , p . 342. S p r i n g , 1966 .

Code o f F e d e r a l R e g u l a t i o n s , T i t l e 10 , P u r t 100 , R e a c t o r S i t e C r i t e r i a . F e d e r a l R e g i s t e r , v o l . 26 , no . 28, p . 1224.

T . H . Row. Spray and Pool A b s o r p t i o n TechnoZogy Program, ORNL-4360. Oak R i d g e Nat ionaZ L a b o r a t o r y , Oak R i d g e , T e n n e s s e e , A p r i l , 1969 .

V . G r i f f i t h s . The Removal o f I o d i n e from t h e A tmosphere by S p r a y s , AHSB(SlR45. UKAEA, A u t h o r i t y and S a f e t y Branch, R i s l e y , Lanes , England , January , 1963 .

T . K . Sherwood and R. L . P i g f o r d . A b s o r p t i o n and Extrac- t i o n . McGraw-Hill Book Co.. New Y o r k . 1952 . 2nd e d . .

J . G . Knudsen and R. K . H iZZ iard . F i s s i o n P r o d u c t T r a n s - p o r t by N a t u r a l P r o c e s s e s i n Con ta inmen t V e s s e l s , BNWL-943. B a t t e Z Z e - N o r t h w e s t , R i c h l a n d , Wash ing ton , J a n u a r y , 1969 .

S t a f f o f B a t t e l l e - N o r t h w e s t . N u c l e a r S a f e t ~ Q u a r t e r Z y R e p o r t f o r November, December, 1967 , J a n u a r y , 1968 , BNWL-816, p p . 2 . 41 -2 .46 . B a t t e Z Z e - N o r t h w e s t , R i c h l a n d ,

G . M . Watson , R. B . P e r e z and M . H . Fon tana . E f f e c t s o f Con ta inmen t S i z e o n F i s s i o n P r o d u c t B e h a v i o r , ORNL-4033. Oak R idge N a t i o n a l L a b o r a t o r y , Oak R i d g e , T e n n e s s e e , J a n u a r y , 1967 .

T . K . Sherwood and R. L . P i g f o r d . A b s o r p t i o n and E x t r a c - t i o n . McGraw-HiZZ Book Co., New Y o r k , 1952 . 2nd e d . , p . 270.

W . E . Ranz and W . R. M a r s h a l l , J r . " E v a p o r a t i o n from Drops , P a r t I and I I , " Chem. Eng. P r o g r . , uoZ. 48, p p . 141-146 and p p . 173-180 . 1952 .

R . B . B i r d , W . E . S t e w a r t and E . L. L i g h t f o o t . T r a n s p o r t Phenomena. John W i l e y & S o n s , I n c . , New ~ o r k , 1960 . p p . 674-675.

L . F. P a r s l y and J . K . F r a n z r e b . Removal o f I o d i n e Vapor from A i r and S t eam- Ai r A tmosphere s i n t h e N u c l e a r s a f e t y P i l o t P l a n t bu Use o f S ~ r a u s . ORNL-4253. Oak R idae a -.

- - -GJ -

N a t i o n a l L a b o r a t o r y , Oak R i d g e , T e n n e s s e e , J u n e , 1 9 6 8 .

P . V . Dankwer t s . " A b s o r p t i o n by S imuZtaneous D i f f u s i o n and ChemicaZ R e a c t i o n i n t o P a r t i c l e s o f V a r i o u s Shapes and i n t o F a l l i n g Drops," T r a n s . Faraday S o c . , voZ . 4 7 , p p . 1014-1023. 1951.

G . L . C o n s t a n and S . C u l v e r t . "Mass T r a n s f e r i n Drops Under C o n d i t i o n s t h a t Promote O s c i Z Z a t i o n and I n t e r n a l C i r c u Z a t i o n , " AIChE J . , voZ . 9 , p p . 109-115. 1963 .

F . H . Garner and J . J . Lane. "Mass T r a n s f e r t o Drops o f L i q u i d Suspended i n a Gas S t r eam, P a r t I I . E x p e r i m e n t a l Work and R e s u Z t s , " T r a n s . I n s t . Chem. Engrs . , voZ . 37 , p p . 162-172 . 1959.

F . H . Garner and P . J . Haycock. " C i r c u Z a t i o n i n L i q u i d Drops," Proc . Royal S o c . , v o l . 252A, p p . 457 -475 . 1959 .

R . Kron ig and J . C . B r i n k . "On t h e Theorq o f E x t r a c t i o n from FaZ?ing D r o p l e t s , " A p p Z . S c i . R e s . , $ 0 2 : A 2 , p p . 142- 154 . 1949.

L . C . Schwendiman, R . A . Hasty and A . K . Postma. The Washout o f Me thy l I o d i d e b y Hydraz ine S p r a y s . ~ i n r R e p o r t , BNWL-935. B a t t e Z Z e - N o r t h w e s t , ~ i c h Z a n d , Wash ing ton , November, 1968 .

P . V . Dankwer t s . " A b s o r p t i o n by S imuZtaneous D i f f u s i o n and ChemicaZ R e a c t i o n s , I f T r a n s . Faraday S o c . , voZ . 46, p p . 300-304. 1950.

J . M . Genco e t aZ. F i s s i o n Produc t D e p o s i t i o n and I t s Enhancement Under R e a c t o r A c c i d e n t C o n d i t i o n s , BMI-1865. B a t t e l l e Memorial I n s t i t u t e , CoZumbus, Oh io , May, 1969 .

G . D . FuZSord. Advances i n ChemicaZ E n g i n e e r i n g . Academic P r e s s , New ~ o r k , 1964 . voZ . 5 , p p . 151-236 .

N . A . Fuchs . The Mechanics o f AerosoZs . The MacmiZZan Co. , New Y o r k , 1964. p . 181 .

N . A . Fuchs . The Mechanics o f AerosoZs . The MacmiZZan Co., New Y o r k , 1964 . p p . 159-170.

W . E . Ranz and J . B . Wong. " I m p a c t i o n o f Dust and Smoke P a r t i c l e s on S u r f a c e and Body C o Z l e c t o ~ s , " I n d . Eng. Chem., U O Z . 4 4 , p p . 1371-1381. 1952 .

L . WaZdmann and K . H. S c h m i t t . "Thermophores i s and D i f f u s i o p h o r e s i s o f AerosoZs , " A e r o s o l S c i e n c e , e d i t e d by C . N . D a v i e s . Academic P r e s s , London, 1966 . p p . 137-162.

T . W . H o r s t . A Rev i ew o f P a r t i c l e T r a n s p o r t i n a Condens- i n a Steam Env i ronmen t . BNWL-848. B a t t e Z Z e - N o r t h w e s t . " 4

RichZand , Wash ing ton , J u n e , 1968 .

W . B . C o t t r e Z Z e t aZ. ORNL NucZear S a f e t y R e s e a r c h and DeveZopment Program B imon th l y R e p o r t f o r May-June, 2968, ORNL-TM-2283, p p . 33- 37. Oak R idge Nat ionaZ L a b o r a t o r y , Oak R i d g e , T e n n e s s e e , J u l y , 1968 .

H . F . Kraemer and H . F . J o h n s t o n e . "CoZZec t i on o f AerosoZ P a r t i c Z e s i n P r e s e n c e o f E Z e c t r o s t a t i c ~ i e Z d s , " Ind. Eng. Chem., voZ. 47, p p . 2426-2434. 1955 .

D . L . M o r r i s o n and S . J . Basham. A n E v a Z u a t i o n o f t h e A p p Z i c a b i Z i t y o f E x i s t i n g Data t o t h e AnaZy t icaZ D e s c r i p - t i o n o f a Nuc l ear R e a c t o r A c c i d e n t , BMI-1810, p p . 29- 39. B a t t e Z Z e Memorial ~ n s t i t u t e , CoZumbus, Ohio , ~ u Z y , 1967 .

S t a f f o f B a t t e Z Z e - N o r t h w e s t . NucZear S a f e t y Q u a r t e r l y R e p o r t f o r November, December, 1967 , J a n u a r y , 1968 , BNWL-816, p p . 2 .30-2 .33 . B a t t e Z Ze- Nor thwes t , R ichZand , W a s h i n g t o n , S e p t e m b e r , 2968.

L. F. CoZeman. P r e p a r a t i o n , G e n e r a t i o n and A n a Z y s i s o f Gases and AerosoZs f o r t h e Con ta inmen t S y s t e m s E x p e r i m e n t , BNWL-1001. B a t t e Z Z e - N o r t h w e s t , R i chZand , W a s h i n g t o n , A p r i l , 1969.

J . D . McCormack. Maypack B e h a v i o r i n t h e Con-tainment S y s t e m s E x p e r i m e n t , A P e n e t r a t i n g A n a Z y s i s , BNWL-1145. B a t t e Z Z e - N o r t h w e s t , R i chZand , W a s h i n g t o n , S e p t e m b e r , 1 969 .

R. K . HiZZiard , L. F. CoZeman and J . D . McCormack. Com- p a r i s o n s o f t h e Con ta inmen t B e h a v i o r o f a S imuZant w i t h F i s s i o n P r o d u c t s R e l e a s e d from I r r a d i a t e d U02, BNWL-581. B u t t e 2 Ze- Nor thwes t , R i chZand , W a s h i n g t o n , March. 7.9CR

B . F . R o b e r t s e t a Z . E v a Z u a t i o n o f V a r i o u s Methods o f F i s s i o n P r o d u c t A e r o s o l S i m u Z a t i o n , ORNL-TM-2628. Oak R idge Nat ionaZ L a b o r a t o r y , Oak ~ i d g e , T e n n e s s e e , S e p t e m b e r , 1969 .

N . P. WiZburn and L . D . C o f f i n . "Combina t i on o f On-Line A n a Z y s i s w i t h CoZZec t i on o f Mu l t i componen t S p e c t r a i n an On-Line Computer ," I B M J . R e s . Dev. , voZ . 13 , p p . 46- 51 . 1969.

36. L . D . C o f f i n . On-Line Computer S t o r a g e and ~ e t r i e v a z o f - P r o c e s s e d Gamma S p e c t r a Data, BNWL-506. ~ a t t e Z Z e - N o r t h w e s t , R ichZand , W a s h i n g t o n , Ju ly , 1967 .

37. J . M . Genco e t aZ . F i s s i o n P r o d u c t D e p o s i t i o n and I t s Enhancement Under R e a c t o r A c c i d e n t C o n d i t i o n s , BMI-X-10229. B a t t e ZZe Memorial I n s t i t u t e , CoZumbus, Oh io , A p r i l , 1968.

38. S t a f f o f B a t t e Z Z e - N o r t h w e s t . NucZear S a f e t y Q u a r t e r Z y R e p o r t f o r November-December, 1968 , J a n u a r y , 1969 , BNWL-1009, p p . 2 . 23- 2 .27 . B a t t e Z Z e - N o r t h w e s t , R i chZand , - - w a s h i n g t o n , March, 1969 .

39. S t a f f o f B a t t e ZZe -Nor thwes t . NucZear S a f e t y Q u a r t e r l y R e p o r t f o r ~ u Z y - O c t o b e r , 1967 , BNWL-754, p p . 2 . 5- 2 .7 . B a t t e Z Z e - N o r t h w e s t , R i chZand , W a s h i n g t o n , J u n e , 1968 .

40. D . L . M o r r i s o n , W . A . C a r b i e n e r and R. L . R i t z m a n . An E v a z u a t i o n o f t h e A p p Z i c a b i Z i t y o f E x i s t i n g Data t o t h e AnaZy t i caZ D e s c r i p t i o n o f a N u c l e a r- R e a c t o r A c c i d e n t , BMI-1850, p p . 39- 43. B a t t e Z Z e Memorial I n s t i t u t e , - - - CoZumbus, Oh io , Oc tober , 1968 .

41 . W . B . C o t t r e Z Z . NucZear S a f e t y Program Annual P r o g r e s s R e p o r t f o r P e r i o d Ending December 31, 1968 , ORNL-4374, p . 28. Oak R i d g e Nat ionaZ L a b o r a t o r y , Oak R i d g e , T e n n e s s e e , J u n e , 1969 .

42. W . A. Freeby e t aZ. F i s s i o n P r o d u c t B e h a v i o r Under Simu- Za ted Los s- o f- CooZan t A c c i d e n t C o n d i t i o n s i n t h e Contami- n a t i o n - D e c o n t a m i n a t i o n E x p e r i m e n t , IN-1171. I d a h o NucZear Corp . , I daho FaZZs, I d a h o , J a n u a r y , 2 9 6 9 .

43 J . G . Knudsen and D . L. K a t z . F l u i d Dynamics and Heat T r a n s f e r . McGrau-HiZZ Book Co . , I n c . , New Y o r k , 1 9 5 8 . C h a p t e r 1 1 .

44. R. A. MugeZe and H . D . Evans . " D r o p l e t S i z e ~ i s t r i b u t i o n i n S p r a y s , " I n d . Eng. Chem., voZ . 4 3 , p . 1318 . 1951 .

45. A . E . J . E g g l e t o n . A T h e o r e t i c a l E x a m i n a t i o n o f I o d i n e - Wate r P a r t i t i o n C o e f f i c i e n t s , AERE-R-4887. U K A E A , A t o m i c Energy R e s e a r c h E s t a b Z i s h m e n t . Harwe 2 2 , B e r k s , ~ n g Zand, F e b r u a r y , 1967 .

46. L . C . Wa t son , A . K . B a n c r o f t and C . W . HoeZke. ~ o d i n e C o n t a i n m e n t by Dousing i n N P D - 1 1 , CRCE-979. A t o m i c Energy o f Canada, L t d . , Chalk R i v e r , O n t a r i o , O c t o b e r , 1960 .

4 7 . A . K . Postma. A b s o r p t i o n o f M e t h y l ~ o d i d e by Aqueous Hydraz ine S o Z u t i o n s W i t h i n Spray Chambers, Ph. D . T h e s i s i n Chem Eng., Oregon S t a t e U n i v e r s i t y , C o r v a Z Z i s , Oregon. 1 9 6 9 . ( I n P r e p a r a t i o n )

4 8 . G . D . Fu Z f o r d . Advances i n Chemica l E n g i n e e r i n g . Academic P r e s s , flew Y o r k , 1 9 6 4 . voZ . 5 , p . 157 .

A P P E N D I X

F A C I L I T Y D E S C R I P T I O N

C O N T A I N M E N T VESSEL

The containment vessel is in actuality three integral

vessels; an outer vessel termed the containment vessel, an

inner vessel termed the drywell, and a compartmented section

between the outer surface of the drywell and the inside sur-

face of the containment vessel termed the wetwells. The sig-

nificant features of the containment systems vessels are shown

in Figure A-1. All three of the components were designed, fab-

ricated, and tested in accordance with the ASME Unfired Pressure

Vessel Code, Section VIII, 1962 Edition. For the spray studies,

only the containment vessel and drywell were used. The wetwells

were sealed off from the other two vessels by the installation

of blinds on the various ports and nozzles. The reactor simu-

lator vessel was not installed and the lid of the drywell was

upright, in the open position.

The 66 ft-8 in. high and 25 ft diam carbon steel contain-

ment vessel was designed for maximum operating condition of

75 psig and 320 O F . The carbon steel plate, SA 212-B, ranged

in thickness from 0.75 in. for the heads, and 0.672 in. for

the bottom shell quarter down to 0.645 in. for the upper three

quarters of the shell. The vessel is located in a concrete

cell within a large building. Approximately half of the vessel

extends above the cell.

The drywell was designed for a maximum pressure of

150 psig and a temperature of 330 O F . The vessel is 25 ft

high and 11 ft in diameter. The heads are standard ASME ellip-

soidal 2:l dished heads with a 0.688-in. minimum thickness.

The shell is a minimum of 0.669 in. thick. The top head is

hinged to provide access for other large equipment pieces.

For these spray experiments, the drywell lid was open for

aerosol dispersion and to obtain maximum fall distance for the

spray. The contained gas volume for the containment vessel

and drywell is 26,477 ft3 (excluding the wetwells).

All vessel surfaces inside the containment vessel, includ-

ing the inside wall of the containment vessel, are coated with

a modified phenolic paint.* After Run A4, the external surface

of the containment vessel was covered with a 1-in. layer of 3 glass fiber insulation [ 6 . 0 lb/ft density, k = 0.027 Btu/

2 (hr) (ft ) (OF/ft)] with a factory applied vapor shield. A view

of the upper half of the containment vessel before the insula-

tion was applied as shown in Figure A-2.

INSTRUMENTATION

A critical part of these experiments was the accurate

measurement of physical conditions existing inside containment.

Knowledge of average temperature and pressure, as well as heat

loss, velocity of convection currents, liquid levels, and

opportunity for direct visual observation are required.

Thermocouples are located throughout the vessels as well as in

the sealed-off wetwell and outside the vessel. They are so

located that simple arithmetic averages will provide an accu-

rate average temperature in the vessel. Thermocouples are also

located near the inside, on the inside, on the outside, and

near the outside wall of the containment vessel to obtain data

for calculating heat losses. A series of commercially avail-

able anemometers*" is installed in a horizontal line across the containment vessel and at several elevations near the

walls. Visual observation, accomplished by the use of a stan-

dard 6-in. diam pressure glass installed on a nozzle 13 ft

* Two c o a t s o f PhenoZine 3 0 2 over one c o a t o f ~ h e n o Z i n e 300 pr imer , a product o f t h e Carbo l ine Co., S t . L o u i s , Mo.

** Heated t h e r m o p i l e t y p e S - 2 2 A X , power supp ly mode2 AM- 62R I O X , manufactured by Has t ings , R a y d i s t , I n c . , Hampton, V i r g i n i a .

Neg 47381-57

FIGURE A- 2. An E x t e r i o r V i e w of t h e Upper Half of t h e CSE V e s s e l Before Thermal I n s u l a t i o n Was I n s t a l l e d

BNWL- 1244

above the main vessel deck, was also useful for evaluating the

quality of the atmosphere, the injection of the aerosol, and

also the fall of the spray solution. Standard dip tube level

gages with manometer readout were used for liquid level mea-

surements of the drywell pool, containment vessel pool, and

the spray solution storage tank.

A E R O S O L G E N E R A T I N G A N D I N J E C T I O N E Q U I P M E N T

The aerosol generating and injection station and equipment

consist of a cave, two standard radiochemical hoods, high fre-

quency induction units, a heated transfer line, a steam jet,

and a panel board. The equipment is located in laboratories

close to the containment vessel. The volatilization of the

radioactive simulant fission product aerosol components, as

well as the generation of the uranium oxide and cladding fumes,

is done in a cave constructed of 6-in. steel walls and equipped

with manipulators. An air stream sweeps the volatilized simu-

lant materials through the U02 melting furnace via the 2-in. ID

injection line through penetrations in the main CSE vessel into

the vapor space in the drywell.

The motive force for aerosol injection is provided by a

steam jet. Since the containment systems may be at pressures

of up to 75 psig, the use of 225 psig steam is necessary to

obtain desired flow rates against this back pressure. Advantages

of the technique include the capability of operating the gen-

erating apparatus without pressure and for using inert friable

materials such as glass for the aerosol generation apparatus.

Other significant features of the system provide for:

Wrapping the line with electrical heating tape and insula-

tion to maintain the line at a temperature greater than

250 O F .to prevent condensation when steam is used as the

carrier gas.

a Electrically heating the 225 psig steam line and supplying

dry or superheated steam to the steam jet by means of a

superheater.

Locating aerosol samplers in the line near the point of

discharge so that the amounts and forms of the aerosol

components entering containment can be determined.

Additional details of the CSE aerosol generation system are

given by Coleman. ( 2 6 )

S,:,HPLING S Y S T E M S

During each aerosol transport and behavior experiment,

many liquid and gas samples were taken during the course of

the experiment for radiochemical analyses at a later time.

Samples of the spray solution as it falls, samples of the

spray solution running down the containment vessel wall sur-

face, samples of solution accumulating in the bottoms of con-

tainment vessel and the drywell, deposition coupons of various

materials and, finally, samples of the gas phase are all

important in the conduct of spray experiments.

The flowsheet for the gas sampling system is shown in

Figure A-3. The scheme consists primarily of Maypack clusters

(multiple filters and adsorbers) located at 14 positions

inside containment for sampling both gaseous and particulate

components. Also included are heated sampler exhaust lines

to the laboratory provided with condensers for collecting con-

densate, and with pressure reducing valves, cold traps to dry *

the air, refrigerated charcoal traps to collect any iodine

penetrating the Maypacks, and the necessary sample flow control b

apparatus.

Figure A-4 is a photograph of a partly disassembled n

cluster showing the 12 solenoid valves and quick disconnects,

with cover removed. Figure A-5 shows the arrangement and types

of filter media in a Maypack.

Elect r ica l Leads

Header

,12 - iI2" OD A i r

, , Basement F loor

GENERAL NOTE

A l l A i r Sampl ing L ines t o t h e Sampler S ia t ions Sr;,all l e Stea;n Traced a n d Insu ld teu to M a i n t a i n A i r Samples at 2X - 300 '~ .

- T o P u n i p F i l t e r & Stack

FIGURE A-3. Schematic Diagram of CSE Aerosol Sampling System

Each of the 12 solenoid valves of a Maypack cluster

assembly is individually controlled at a panel in the labora-

tory so that samples of the atmosphere can be taken at a speci-

fied point in containment as a function of time. A system of

pulleys, cables, and winches is provided for raising or lower-

ing an assembly to a desired location. Flexible Teflon tubing

serves as the exhaust line from an assembly to the vessel wall

where it connects to a 0.5-in. diam stainless steel tube. The

stainless tube penetrates the vessel wall and then is gathered

into a bundle with the other sample exhaust lines. The bundle

of stainless steel tubes continues the run into the laboratory

to the final sampling and metering equipment. The sample

exhaust line bundle is steam traced from the containment vessel

to the laboratory to prevent condensation. Retrieval of the

samples taken by the Maypacks located within containment is

postponed until the experiment is ended and the containment

vessel thoroughly purged with fresh air.

Each terminal aerosol sampling station in the laboratory

consists of a condenser, condensate receiver, pressure reducing

valve, cold trap, refrigerated charcoal trap, rotometer, and

the appropriate valves and gages required for flow control.

The total gas volume is determined by correcting the rotometer

readings to terriperature and pressure conditions at the respec-

tive Maypack location within the containment vessel. All gas

samples taken by Maypacks in the CSE are routinely obtained for 3 a 3-min flow duration at 0.5 ft /min (STP) flow of dry air.

Samples of the liquid collected in the bottoms of the

drywell and containment vessel are taken from separate recir-

culating loops located externally to the vessels. Each loop

is an independent system and consists of a pump, heat exchanger,

a sample spigot, a mixer-eductor, and associated transfer line

and valves. The heat exchanger is necessary to prevent

f l a s h i n g of t h e l i q u i d when t h e sample s p i g o t i s opened.

Vo lumet r i c samples a r e t a k e n and r a d i o c h e m i c a l l y coun ted

d i r e c t l y under known g e o m e t r i e s .

S o l u t i o n f l o w i n g down t h e w a l l s of t h e con ta inmen t v e s s e l

i s c o l l e c t e d by a c i r c u m f e r e n t i a l t r o u g h l o c a t e d n e a r t h e main

deck l e v e l . The t r o u g h i s d r a i n e d t h r o u g h a f l o w r e c o r d e r t o

a sample s p i g o t . Only a s m a l l f r a c t i o n of t h e f l o w is t a k e n

f o r s a m p l e s , w i t h t h e r ema inder r e t u r n e d t o t h e p o o l a t t h e

v e s s e l bot tom.

Samples of t h e f a l l i n g s p r a y d r o p s a r e t a k e n a t two e l e -

v a t i o n s and t h r e e r a d i i . Suspended i n t h e v e s s e l a r e f u n n e l s

o f known geometry which d r a i n v i a 1 / 2 - i n . t u b i n g i n t o s m a l l

p r e s s u r e v e s s e l s l o c a t e d o u t s i d e t h e con ta inmen t v e s s e l . Each

s m a l l v e s s e l i s v e n t e d back t o t h e con ta inmen t v e s s e l t o a s s u r e

good d r a i n a g e . F r e q u e n t l y d u r i n g t h e s p r a y p e r i o d s , t h e s m a l l

p o t s , a r e i s o l a t e d , v e n t e d t o a tmosphere , and d r a i n e d of t h e

s o l u t i o n c o l l e c t e d . The volume c o l l e c t e d i s r e c o r d e d and a

p o r t i o n i s saved f o r r a d i o c h e m i c a l a n a l y s i s .

I n o r d e r t o o b t a i n g a s samples d u r i n g t h e c o u r s e of t h e

r u n , a s p e c i a l chamber i s i n s t a l l e d on a v e s s e l n o z z l e s o t h a t

i n d i v i d u a l Maypacks can be i n s e r t e d i n t o t h e v e s s e l a t any

t i m e , a sample drawn, and t h e Maypack removed from t h e v e s s e l .

Ana lyses of t h e s e " t h i e f " samples p e r m i t p r e l i m i n a r y a p p r a i s a l

of t h e e x p e r i m e n t .

S P R A Y S Y S T E M

The b a s i c equipment f l o w s h e e t used f o r t h e CSE s p r a y s y s -

tem i s shown i n F i g u r e A - 6 . Changes, i f a n y , from one e x p e r i -

ment t o t h e n e x t were found p r i m a r i l y t o i n v o l v e a l t e r a t i o n s

t o t h e s p r a y d i s t r i b u t i o n sys t em. I n some i n s t a n c e s , o n l y t h e

n o z z l e s were changed. I n o t h e r i n s t a n c e s , changes t o t h e d i s -

t r i b u t o r p i p i n g were r e q u i r e d . The sys t em, though s i m p l e , was

v e r y f l e x i b l e . S a n i t a r y w a t e r o r d e m i n e r a l i z e d w a t e r , o r e i t h e r

of these with chemicals added, could be used for the spray

solution. Also the spray solution could be recirculated from

the containment vessel sump back to the spray distributor and

nozzles. The recirculated solution could be cooled as desired

by routing it through a heat exchanger.

The header and nozzles were installed so that the system

could be filled prior to the start of the experiment. Thus

when the ball valve was opened or closed, start or stoppage of

flow through the nozzles was realized immediately. This accu-

rate and close timing of spray periods was important later for

the correlation of the data. The flow was manually controlled

by adjusting the control valve to give a specific pressure

drop across the nozzles. The nozzle manufacturer's data on

flow rate and droplet size were used to determine the pressure

drop desired. Pictures of the types of nozzles used, along

with some specifics, are shown in Table 2. The nozzles were

installed at plus 28.5 ft to provide a drop height of 33.8 ft

to the deck and 50.5 ft to the bottom of the drywell. A course

strainer (0.053-in. openings) was installed at the outlet of

each vessel sump. Two additional strainers were located in the

supply line leading to the spray nozzles, as shown in Figure A-6.

D I S T R I B U T I O N

No. of Copies

OFFSITE

AEC Chicago Patent Group

G. H. Lee

AEC Division of Reactor Development and Technology

W. G. Belter R. S. Brodsky (2) J. W. Crawford R. L. Ednie D. E. Erb W. P. Gammill A. Giambusso H. L. Hamester H. G. Hembree E. E. Kintner R. R. Newton (5) R. E. Pahler (2) A. J. Pressesky (5) H. J. Reynolds I. C. Roberts M. A. Rosen E. E. Sinclair S. A. Szawlewicz G. W. Wensch M. J. Whitman

AEC Division of Technical Information Extension

AEC Library, Washington Advisory Committee on Reactor Safeguards

F. R. Fraley (18)

Division of Compliance

L. Kornblith, Jr. L. D. Low

Division of Compliance, Region IV J. W. Flora

Division of Operational Safety

H. Gilbert

No. of Cop ies

D i v i s i o n of P r o d u c t i o n

G . B . P l e a t

D i v i s i o n of Reac to r L i c e n s i n g

R . S . Boyd G . B u r l e y B r i a n Grimes S . Levine D . J . Skovho l t

D i v i s i o n of Reac to r S t a n d a r d s

G . Bur l ey E . G . Case ( 5 ) A . R . H o l t J . E . McEwen, J r . J . R . M i l l e r I . S p i c k l e r

1 AEG-Telefunken, Germany 816 J e r i Ave. Idaho F a l l s , Idaho 83401

D i e t e r Ewers

1 A e r o j e t - Genera l Idaho F a l l s

W . E . Nyer

American E l e c t r i c Power S e r v i c e Corp. 2 Broadway, New York, N . Y . 10004

P. Dragoumis S. J . M i l i o t i A . Sherman

8 Areonne N a t i o n a l L a b o r a t o r y

C . E . Dickerman S . F i s t e d i s R . 0 . I v i n s P. L o t t e s R . C . Vogel

LMFBR Program O f f i c e

A . Amorosi L . Baker C . E . M i l l e r , J r .

No. of Copies

Atomic Energy C o n t r o l Board Ot tawa, Canada

F . C . Boyd

Atomics I n t e r n a t i o n a l -- - -

H. Morewitz (2)

L iqu id M e t a l s Engr Cen te r

R . W . D ick inson

Babcock 6 Wilcox Co. Lynchburg, V i r g i n i a

W. S . D e l i c a t e D . A . N i t t i R . Wascher

B a t t e l l e Memorial I n s t i t u t e

A . R . Duffy D . L . Mor r i son S. P a p r o c k i (2) R . L . Ritzman D . N . Sunderman (2)

B a t t e l l e Memorial I n s t i t u t e F r a n k f o r t , Germany

G . L e i s t n e r / K . J . Kober N . Henzel

B e c h t e l C o r ~ o r a t i o n (AECl

B. K . Lee G . S . C . Wang

B e c h t e l C o r p o r a t i o n P.O. Box 607 G a i t h e r s b u r g , Md. 20760

H . W . Osgood

Brookhaven N a t i o n a l Labora to ry

A . W . Cast leman

Canadian Genera l E l e c t r i c Co. P e t e r s b o r o u g h , O n t a r i o

S . Davies

No. of Copies

Canoea Park Area O f f i c e

R . L . Morgan

C e n t r e d t E t u d e s N u c l e a i r e s de S a c l a y P.O. Box 2 Gif s u r Y v e t t e ( S e i n e - e t - O i s e ) , France

P . Candes

Chalk R i v e r Nuclear L a b o r a t o r i e s Chalk R i v e r , O n t a r i o , Canada S t a t i o n 3

G . Hake

Chicago O p e r a t i o n s O f f i c e Atomic Energy Commission

D . M. G a r d i n e r

Combustion E n g i n e e r i n g

M . F. V a l e r i n o

C o n s o l i d a t e d Edison Company

J . J . Grob

Consumers Power Company J a c k s o n , Michigan 49203

G. S . Keeley G . B . Matheny H . S. T s a i

D i l w o r t h , S e c o r d , Meagher, and A s s o c i a t e s , L t d . 4195 Dundas S t . T o r o n t o , O n t a r i o , Canada

I . J . B i l l i n g t o n

duPont Company (AEC)

A . H . P e t e r s

Ebasco S e r v i c e s , I n c . 2 R e c t o r S t r e e t New York, N . Y . 10006

Harold O s l i c k

No. of Copies

Genera l E l e c t r i c Company, C i n c i n n a t i (AEC)

J . F . White

Genera l E l e c t r i c Company, San J o s e

D . J . L i f f e n g r e n M . S i e g l e r D . P . S i egwar th S. Vandenberg G . E . Wade E . Zebrosk i

Genera l E l e c t r i c Company, San J o s e (Trumbull)

P . Bray W. A . S u t h e r l a n d

Harvard A i r C lean ing L a b o r a t o r y

M . F i r s t F . J . V i l e s

Idaho Nuclear C o r p o r a t i o n

D . E . Black G . 0 . B r i g h t J . A . Buckham W. H. Burgus D. deBoi sb lanc C . H a i r e J . H . K e l l e r L . T . Lakey J . A . Norberg D . T . Spence C . M . S l a n s k y N . K . Sowgrds D . H . Walker Y . A . Y u i l l

Idaho O ~ e r a t i o n s O f f i c e

D . Wi l l i ams

I I T Research I n s t i t u t e

E . V . G a l l a g h e r T . A . Zaker

No. of Copies

Inst. f. Mess- u. Regelungstechnik D8046 Garching, Germany-West

Dr. H. Karwat

Los Alamos Scientific Laboratory

J. H. Russel

MPR Associates, Inc.

T. Rockwell I11

National Bureau of Standards

C. Muehl hause

Naval Ordinance Laboratory

J. Proctor

North Carolina State University

M. N. Ozisik

Nuclear Fuels Services

R. P. Wischow

NUS Corporation 2351 Research Blvd. Rockville, Md 20850

M. I. Goldman

NUS Corporation Washington, D.C.

R. S. Denham

Oak Ridge National Laboratory

R. E. Adams B. F. Roberts R. L. Bennett T. H. Row R. Blanco D. B. Trauger J. Buchanan G. M. Watson W. B. Cottrell (4) H. E. Zittel D. Ferguson M. H. Fontana G. W. Parker L. F. Parsly, Jr. P. Rittenhouse

No. of Copies

1 Oak Ridge Operations Office (AEC)

W. L. Smalley

Oregon State University

James G. Knudsen L. P. Bupp

Pickard, Lowe and Assoc. 1200 18th St. N . W . Washington, D.C.

Keith Woodard

Public Service Electric and Gas Co. 80 Park Place Newark, N. J. 07101

R. P. Douglas

San Francisco O~erations Office fAEC)

C. V. Backlund

Sargent and Lundy Chicago, Ill.

0 . Hrynewych

Southern Nuclear Engineering, Inc. Dunedin, Florida

Gilbert Brown R. L. Lyerly C. Rogers McCullough

Spray Engineering Co. Burlington, Mass.

W. E. Hebden

Spraying Systems Co. Bellwood, Ill.

E. S. Gray

Stone 4 Webster Engineering Corp. 2 2 5 Franklin, Boston, Mass. 02107

L. T. Deackoff J. H. Noble

TRW Systems (NASA)

D. B. Langmuir S . M . Zivi Distr-7

No. of Copies

University of California, Berkeley Institute of Engineering Research

H. A. Johnson V. E. Schrock

University of Minnesota Department of Chemical Engineering

H. S. Isbin

University of Washington

R. W. Moulton

Westinghouse Electric Corp. (APD)

E. Beckjord W. D. Fletcher J. D. McAdoo R. A. Wiesemann

Westinghouse Electric Cor~. (IITD)

A. Lohmeier

Yankee Atomic Electric Co. 441 Stuart St., Boston, Mass.

J. DeVincentis P . S. Littlefield

ONSITE-HANFORD

1 AEC Chicago Patent Group

R. K. Sharp (Richland)

AEC RDT Site Representative

P. G. Holsted (2) J. B. Kitchen

AEC Richland O~erations Office

A. Brunstad C. L. Robinson (2) W. E. Lot2

No. of Copies

3 Atlantic Richfield Hanford Company

0 . F. Hill G. R. Kiel ARHCO File

3 Battelle Memorial Institute

6 Douglas United Nuclear

T. W. Ambrose E. L. Etheridge N. R. Miller J. W. Riches J. R. Spink DUN File

7 3 Battelle-Northwest

F. W. Albaugh E. R. Astley R. T. Allemann J. M. Batch R. H. Bond S. H. Bush L. F. Coleman D. L. Condotta F. G. Dawson J. M. Hales M. M. Hendrickson R. K. Hilliard (10) T. W. Horst R. L. Junkins J. P. Hale B. M. Johnson C. E. Linderoth J. D. McCormack R. E. Nightingale A. K. Postma D. L. Reid G. J. Rogers (30) C. L. Simpson J. C. Spanner N. P. Wilburn M. E. Witherspoon N. G. Wittenbrock Technical Information Files (5) Technical Publications ( 3)

Documents

February BATTELLE MEMORIAL INSTITUTE · 2018. 1. 30. · 3 3679 00061 6393 BNWL-1244 UC-41, Health and Safety REMOVAL OF IODINE AND PARTICLES FROM CONTAINMENT ATMOSPHERES BY SPRAYS--