Uranium 01

1 Ii

1

OAK RIDGE NATIONAL LABORATORY operoted by

UNION CARBIDE CORPORATION

for the

U.S. ATOMIC ENERGY COMMISSION •

ORNL - TM - 230 .9)c ) c/y-

COpy NO. - C'

DATE -

StWER-PROMPT-CRITICAL BEHAVIOR OF AN UNMODERATED, UNREFLECTED ~IUM-MOLYBDENUM ALLOY ASSEMBLY

J. T. Mihalczo

Abstract

May 10, 1962

The t~me-dependent behavior of the neutron population in an unreflected,

unmoderated cylindrical assembly of a 90 wt% uranium (93.2 wt% ), 10 wt%

molybdenum alloy following a rapid establishment of a super-prompt critical

condi tion with negli.gible initial neutron population has been investigated

to support the design of a reactor capable of producing bursts of 1017 fis

sions. Reactivity increases up to 11 cents above prompt critical resulted

in bursts yielding as many as 1.8 x 1017 fissions with reactor periods as

short as 16 ~sec and temperature increases as large as 400oC. Pressure

waves generated in a portion of the core held in position by an electro

magnet for bursts greater than ~ x 1016 fissions initiated the removal of

this section of the core about 225 ~sec after the peak of the burst.

NOTICE

This document contains information of a preliminary nature and was prepared primarily for internal use at the Oak Ridge Natianal Laboratory, It is subject to revision or correction and therefore does not represent a final report, The information is not to be abstracted, reprinted or other wi se gi ven publ ic di ssemination without the approval of the ORNL patent branch, Legal and Information Control Department,

r~-----~------------~~~"~---------LEGAL NOTICE-- -~-------------------------,

This report was prepared as an account of Government sponsored work. Neither the United States t

nor the Commission, nor any person acting on behalf of the CO!Tlmission:

A. Mukas any warranty or representation l expressed or implied, with ,,,spect to the accuracy,

completeness, or usefulness of the information co;,tained in this report, or thot the use of

ony information, apparatus, method, or ptocess dtil-closed in this report may not inftinge

privately owned rights; or

B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of

any information , opparatus t method, or process disclosed in this report.

As used in the above, "person acting on behalf of the Commission·' includes any employee or

contractor of the Commission, or employee of such contractor, to the extent that such employee

or contractor of the Commisston, or employee of such contractor preparest dtsseminates, or

provides access to, any information pursuont to his employment or contract with the Commission,

or his employment with such contractcr.

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Introduction

The design of a bare metal reactor intended to produce high-intensity

bursts of neutrons having a near=fission spectrum has been described by

Breidenbach et 1 Similar in principle to the Los Alamos Lady Godiva

and Godiva II bare U235 reactors, the present design obtains greater

strength and improved physical characteristics through the use of a 90 wt%

uranium ~ 10 wt% molybdenum alloy in its construction

enriched to 93,2 wt% u235 .

The uranium is

A previous paper2 described a series of zero-power experiments wLth

this assembly. Those results included reactivity calibrations of various

parts J fission'4rate distributions, and reacti vi ty effects of reflective

materials near the reactor"

The time behavior of the reactor during super-prompt-critical neutron

bursts of various sizes is described here, All experiments were conducted

indoors at the ORNL Critical Experiments Facility. Reactor periods, burst

shapes, temperature changes, leakage fluxes, and fission yields were mea

sured. The observed bursts were compared to theoretical predictions de~

rived from the one~group, space~independent model given by Wimett et al,3

Description £[ Apparatus

The assembly used i.n these experiments is the ORNL Health Physics

Research Reactor (HPRR), It is essentially a 20 32~cm-dia by 23-cm-high

cylinder of uranium-molybdenum alloy with a 5-cm-dia steel core, A

detailed drawing of the reactor is shown as

photographs of the final assembly 0

" 1, and Figs., 2 and 3 are

An 8,6"cm-OD annulus, containing 9,4 kg of the total 9606 kg of 1f235

in the reactor, is attached to the lower end of the magnetically supported

steel core and serves as a safety block. A motor drive moves the magnet

L G, Breidenbach et a1., Preliminar;y Design of the ORNL Fast Burst Reactor , NDA~213b~1 (July 30, 1960)"

2.. JoT, Mihalczo, Reactivi t;x:, Calibrations and Fission-Rate Distribu~, tions of an i.Jnmoderated, Unreflected, Uranium~Molybdenum Alloy Research Reactor, ORNL~TM-189 (to be published),

3. T, F" \iimett et a1., Nuclear Sd .• and Eng, 8, 691 (1960),

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PLUGGED HOLE FOR SAMPLE INSERTION ~

CENTER PLOO· (SS)

THERMOCOUPLES 2j

3

UNCLASSIFIED ORNL-LR-DWG 65369

Ov! MASS ADJUST ROD (U-Mo)

I I ~.~ . <1

I ·'.L... A r1BOLTS B BOLT PLUG l r L t; (U-Mo) '~::- {~_. ,t. ,_ .. '

-.. ~ f j,'

f y :~-

J

REGULATING ROD (U-Mo)

.-SAFETY BLOCK (U-Mo)

1 _---SAFETy TUBE (SS) r

. 1. ORNL Health Physics Research Reactor.

4

Fig. 2. ORNL Health Physics Research Reactor.

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. 3. ORNL Health Physics Research Reactor.

6

holding the steel core upward to insert the safety block in the reactor.

As it moves upward, it compresses a spring which, when the magnet is

de-energized, ejects the block with an acceleration of 2.28 g,

Two uranium-molybdenum control rods, worth 195 and 83 cents, respec

tively, are positioned by motors to achieve delayed critical. Neutron

bursts a.re produced by rapid pneumatic insertion of a third rod. Although

the full worth of this rod is $1.15, during the present work a part of

the rod was fixed in t~e core and only the remainder of its length was

used for burst production resulting in a reactivity change of about $1,00,

Burst ~ration

The production of a typical burst with a low-power run with

the burst rod partially inserted, during which a. rod configuration was

established which gave the a known amount of positive reactivity_

The level of reactivity was determined by measurement of its associated

stable period. The block was then retracted for about 20 minutes)

allowing the neutron population to decay. With the external neutron

source removed the safety block was then reinserted, increasing the

reactivity to as much as 11 cents above critical, and the burst

rod immediately Hfired" into the core, making the assembly super-prompt

critical. The resulting power excursion was quenched by thermal expa;:'l~

sion of the core and the residual plateau power level was terminated

by removel of the safety -block, 'llie thermal shock resulting from bursts

of > r..6 x 1016 fissl.ons separated the steel core from its supporting

magnet, automatically removing the block from the assembly;

however, the acceleration of the safety block was not significantly

greater than that in a normal instrument-actuated scramc

Instrlllnentation

The stable reactor period during the low-power run prior to burst

production was obtained from measurements, made with three BFs propor

tional counters, of the count rate as a function of time,

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'7

Time behavior of the flux was observed by means of a

~~25-cm-OD, -v25-cm-long cylindrical plastic (polystYilCene with terphenyl

and POPOP) scintillation detector. The scintillator, viewed by a

current photocell, was placed about 90 cm from the assembly to minimize

the effect of scattered radiation and is shown in Fig. 4. The output

current from the photocell was fed through terminated coaxial cable to

produce vertical deflections in several camera-equipped oscilloscopes.

Linear horizontal sweep rates and vertical amplifications were varied to

best display the burst under observation. Triggering of the scope sweep

was effected by a voltage pulse generated by a small scintillation cmmter

when the incident flux exceeded a predetermined level. Camera shutters

"ere triggered manually.,

The total fission yield of each burst was obtained by measuring the

p32 beta activity induced in each of three compressed sulfur pellets

located respectively 0, 86, and 183 cm from the reactor surface, Sulfur

activation was calibrated in terms of total fission yield by comparison

"Ii th the results of radiochemical fission-product analyses of a urani"Um~

molybdenum sample exposed in the vertical irradiation hole of the rea,~

tor, The ratio between the fission denSity in the sample and the total

number of fissions in the reactor was obtained from the fission distribu~

tion calculated by Kinney which had agreed with the limited available

experimental measurements. 2 The data from which the fission yields were

determined are given in the appendix.

ilie fission rate in terms of the phot.ocell output was determined

measuring the entire time-voltage integral of a burst trace up to the

scram point and equating it to the number of fissions determined from

sulfur activation. The photocell output was calibrated :Ln this way for

each run in which a burst trace up to scram time was obtained. Wnen a

tc:'ace was termtnated earlier, the ratio of its signal to tha.t of a

calibrated run was used to determine the photocell output.

The reactor period for a burst was determined from the early part

of the rise in the fission-rate trace before the temperature of the

assembly increased.

8

IC SCINTILLATOR

--- CRASH PIPE

Fig. 4. ORNL Health Physics Research Reactor and Scintillation Detector.

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Two iro!l-constantan therrnocoup::"es attached-r,o two of the annular

disks that make up the core measured the t.empera.ture. The therrnoco1~ple

leads were brazed into brass plugs which were screwed into the

disEs, The output was displayed on a recorder so that both the initial

t.emperature and the curve of cooling following a burst ~ould be ob··

served_ 'The eccentric locations of the thermoc.ouples in the reactor,

shown in • 1, resulted in temperature measurements which were

':!n.lculated to be 7% a!ld 15% below the true peak temperature of the re~

actor. The :;emperature changes given below have been corre::;ted., 'by

computations based O:rl calculated fission dis.l.:;ributions a.nd, thermo:;ouple

to true peak temperature changes. Tl:'£ calctil::::t:te5 fission

distribution ir:dicates that the pea.k-to-average p.)wer ratio

Res'Jlts

The reciprocal positive reactor period, CJ., measured during the early

part of a burst, is plotted in Fig. 5 as a fLl,"1ction of the reacti vi.ty of

-l:;he assembly after insertion of t.he ~urst r-:)d o The interc;ept with th'3

abscissa of a. straight lirie, obtained by a, linear least~squares fit of

:,he da"'.:,a, shows that the prompt-cri ti,~al condition waf' cents above

+;he reactivi t;r of the burst. rod, Thus, the associated wi t':1 the

l;L.;.rs~. rod st.roke was 990 75 ~ o. cenJ..;s 0 The slope of the

t.r'ce space-Lndeperident, one-velocity theory

is th8 prOI!l,pt~neutron decay constant at delayed "riti ~al.J 0]:;. ZnE' Y,'Oll.'le

Dr CJ.p cib-t:.aLn.ed. by a least-squares a.nalysis of t.he da.b;, for a.Ll OC5.,l

x sec :;::}:,.is is

t~J be c:cmpared with a value of ().6'7 :x: w. E.

Ki,'YJ.n.ey ,9.,sstaning 00 as the effect:i.ve fra.::t:'rm of del.aYEd r:.eutrons,

::he (;OTI1}Jlltation is based on a valUE: ;)f t.he Efet;ime ,:)f

X 10 -8 which was calculated by pertur'baticm theory using the

c.n':.!/llar fluxes from an S4 tra.nsport code. 2 'rhe effer~+:, Qf neutrons

re~,urned to the assembly by the walls and r;'.oor ;)f the room may be th:;

reas,x!. for th~ differen,~ebetween the f'xperimental. and ca~.eulat€d val:Jes

of O'p in the present. work.

Ix 104 )

6

5

o Q

'" ~ <i 3 u o '" "-u w

'" .; 2

o o

10

I I • MEASUREMENTS INDOORS AT THE

ORNL CRITICAL FACILITY

BURST ROD STROKE = 18.92 em

WHEN INSERTED, END OF ROD

1.02 mm ABOVE BOTTOM OF

ASSEMBLY

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UNCLASSIFIED ORNL-LR-DWG 67BOlR

y

/ V

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~o, . 0.» , 0.00 ,,'" '''-,

• / --

1/ I /iROMPT

CRITICAL ---

/ !

I 0.02 0.04 0.06 0.08 0.10 0.12

REACTIVITY ABOVE BURST ROD I dollors)

Fig. 5. Reciprocal Reactor Period as a Function of Reactivity Above Burst Rod for the HPRR.

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Some typical burst traces, replotted from the oscilloscope photo

graphs) are shown in " 6, 8, 9, and 10. Other burst t.races obtained

a:ce included in Appendix B. Z~ro time is always arbitrary. The figures

also list reactor period, burst half width, peak fission rat.e, and the

total fission yield.

In the burst of 6) the residual plateau is quite evident.

From the burst shape, the temperature rise, the calculated peak-to

average power density distribution, and the reactivity above prompt

critical required to produce the burst, the average dynamic temperature

coefficient for the burst of Fig, 6 was computed to be O. cents/oC.

Alse shown on this figure are the time of initial safety block motion, ob

tained. from the signal of a transducer attached to the blo-ck} and. the

reaetivity associated with its displacement as a function of time. The

latter quantity was readily obtained from the known reactivity of the

b::Lock as a function of displacement (80 cents/em over the first 2.5 cm)

and the known motion of the block as a function of time after release.

In the actual oscilloscope photograph of 7, a burst of somewhat

greater yield than that of Fig, 6 is shown. Oscillations of the

'Lude of the residual plateau are visible These oscillations stem from

the vibration in the plates of the assembly. This vibration is in th,:;

vertical direction with a frequency, according to the photograph, of

/?;bou!:, 5 kc/sec. It is apparently possible for this vibration to

the core disks, since the bolts which hold the >~ore together were loose

many experiments. Independent measurements of the vibration of

1.he system following a burst indicate a frequency in the vertical diree

tioY1 of about 6 kc/sec, while the vibrational frequency in the radial

d:'.rection was about 22 kc/sec.

Figure 8 shows a burst of 7.2 x fissions, where the pressur':;

waves in the safety block have separated it from its magnet about

iJ.sec after the of the burst, In four ClU'I'erent bursts in

which this shock-separation was observed, the time was found to be

between 220 and 235 iJ.sec after each

12

UNCLASSIFIEO ORNL-LR-DWG 67814R

18 ;'5

'" t: 16 '" 2

14

;'0 z 0 i= 0 ::!:

PERIOD: PEAK RATE:

.. 12 "8 "

25 ::.:: u 0 ..J al

HALF-WIDTH:

>-

~ 10 :0 15

>-20 f-

W ll.. <t (fJ

8 ::!: w f-<t

15 0 0:: ll..

0::

Z 6

0 Ui

>-f-

lO '> i=

(fJ 4 c;: u

<t W 0::

5 w 2 >

~ (!)

0 0 w z

0 5 to t5 20 45 50 TIME (msec)

Fig. 6 Trace of Oscilloscope Photograph for. a Burst of 1. '7 x lO~6 Fissions (HPRR).

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uJ I<I: 0:::

Z o (f) if)

13

TIME


TIME SCALE: 217.4,usee/division

TOTAL YIELD; 4 x 1016 fissions

PERIOD: 45,usee

HALF-WIDTH: 175,usee

PEAK RATE: i. 2 x 1020 fissions Isee

7. Oscilloscope Photograph for a Burst of 4 x 1016 Fissions

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UNCLASSIFIED ORNL-LR- DWG 67808R

14 ------,-----,-----,_--... ~_r----_,----_,------,_~ .. --,_----,_----,

~ 10L-----+-----+-~··---···~----~-·····

§ "" ~ 8 +----········+-----~--······~~t····~--_H~--e " w ~ 6

z o

TOTAL YIELD; 7.2 < 10 16

PERIOD: 24 p'sec HALF -WIDTH: 80 p'sec PEAK RATE: 6.0 • W20 f;ssionsjsec

POINTS ARE FROM SIMPLE NORMALIZED AT PEAK

~ 4+-----+---~-r-f--+_----~~~_r-----+··········--~------r_----+_--··········1 en c;:

1O0 200 TIME (I'Sec)

300 400 500

• 8. Trace of Oscilloscope Photograph for a Burst of 7.2 x lO~6 Fissions (HPRR).

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UNCLASSIFIED ORNL-LR-DWG 67810R

12 ,---------r----r-1---r---,-----1.-----:-. ----;---'--1 --10 1---+---+---i1"I'--'\c---+~ TOTAL YIELD: 1.05 x ml7 fissions

~ \ PERIOD: 20 "sec :;; J HALF - WIDTH: 63 /1- sec

~ :0

~ 81---+.--.:---.........

j-++-----l\I-+__ PEAK RATE: 1.3 x 10 21 fissions/sec

~ 61---+---+-~~+-···~~-···~--~--~--~-~······+··············· ....... .

~ / \ ~ ::~~~~:~~~~~:~~~~~:~~~~~:I\:~~~:~~~~~:~~~··-~-···~··-r

L/ I,,{

,~-

oL-~~ .... ~ ................... L __ ~ __ ~==i=~~~~~ ........... __ __ o 100

Fig. 9. Trace of Osc Fissions (HPRR).

200 300 400 500

for a Burst of 1.05 x 1017

u '" ~ Ul c: .2 Ul

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UNCLASSIFIED ORNL-LR-DWG 66t66R2

(x 102t)

3.0

2.5

2.0

1.5

1.0

0.5

0

YIELD: L8 x 1017 fissions f---+-------iJ--+---+- PEAK RATE: 3.0 x 1021

~ __ + __ i'----\--+- MAX. TEMPERATURE RISE: 400·C

0 50 tOO

PERIOD:

HALF -WIDTH:

REACTIVITY ABOVE

t50 200 250 TIME (fLsec)

16 p'sec

48 p'sec

300

. 10. Trace of Oscilloscope Photograph for a Burst of 1.8 x 10~7 Fissions (HPRR).

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A'ts,) ShC;WL in thiB figure ~.a thecretica,J,-~t 5hapej-'~Qn

Hre oncwgrEflJ:p medel previ::n;u.ly noted, The (H:H"ves have been nl)I'maliBed

at--:tbeirs :peaKs~ In all-eompar:Lsons b€bT€l€lD ~ and experiment, agree

menL8J)peaxed good hl the r1slng pa.rt of -the--~H'B-'try but the 1'1eutJ::oD,

d~y i-rt-tAte~X'PerimentswasTilways-Ta,s 'terpredic ted by-~alcula tion.

~--'?alc tilatien., ho',,'Cv~:r ~ ass (:mte8~-eon:ot~4,'€ffiperatur.e.""'c.oeffj cien:.LDl

,;r::ea,::t.i vi ty

inereaoc; Llte ~'2t11pel'aLU1e c(leJfl~lent:: of read:i~ity may actuall,¥ ha.~,~

·'\mer.i.on:Jf syatcm tempelatu:r~, thug :.~,ll:singt~,~to-~ne':::ay~r

tfl8:,n pI edi e1:,cd;;--

Figl:;,r.;::s 9 and 10 show 'c ursts of l.. x: and L8 x fissions,

I'espe~ti vely,

In tbe burst of ..L,8 x 1017 f5.ssionsl' the peak temperature rise was

4ococ ~ up to the time of the of the burst 45%:::lf the fis-

sions had t.he t,herrna~ expar;sion at t.hat time was only suf~

fi~ient t,) reducef;he re8,,~tivi tv 11 cen'!:,s, '1'h-:.s indicates, as was

E:xpeeted, that; the thermal expa:ns~Jm behind the energy release.

Fission versus tempera+,ure r:tse is plotted i.n Fig .. l,L The

cb'aim:d by using ~ c heat of C.042

for the urani ,'"Un-lU"";.J-,

178 Mev /f1ss1on f.;)r ttLe er:;.ergy depos.i t.ed in the

al10YJ and assumtng

gives 3,8 x 101.4

+.em:;:JEra.+,ure increase. S::1,F. measured

value :i,8 4.6 x A b~rst ~f 5.2 x flssi':'H1S would

ra.ise t:ne peak in ttle assembly to the melting

'n~e peaK fJss i.on I'8t,8 a.s a function of reactor rec.ipro~&.l period

is shown in F:Lg~ l2. the;)r;v predicts that the peak fission ra+je

is proportior~al t.o t,he square of the

deviate a"::. bo-l:.h ends:Jf the ,:~urve,. For

'l'he data

than 3U Ilsec the

deviations are due t·:: ';:,he effe:::L of r:.e1,;"trons s(~attered back

from +;he room walls tl,nd flo:JI'" Fer peri,)ds shorter than 3C l-Lsec, more

intense tnrstsr,han were predic+~ed were bec8,use of th~ la3

'betwe<';:G i'.iS8 .. L:)[l e,~:e!'gy re,iease I'l.Yld expa.nsion of the reaCl,OI' volume.

0 -' w >= z Q (f) (f)

u:

15

10

5

/ ./ o o

18

/ FISSIONS = 4.6 x 10

14 lIT~ ~/ /

/.// /'

UNCLASSIFIED ORNL-LR-OWG 67804

/

/ /

./

V // ./

[/

~ ~ ~CALCULATED FISSIONS = 3.8 x 1014 LIT

P / V

100 200

TEMPERATURE RISE (OC)

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300 400

Fig. 11. Total Fission Yield as a Function of Temperature Rise in the RPRR.

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~

u Q) III ...... III c 0

III III -w I-<1: a:: z Q (.f) (.f)

li: · . ::s::: <1: w Cl..

.. ,

5

I

2

1021

5 I

I

2

I

1020

5

2

1019 I

5 I ... -

/ V •

~ ., 2

2

19

=R I

-1

== I

! .-

I I


~ ~ I

I 11 , r

I I I

• I I , .- 1 • 1

i. I

/ I

! V 1/

I './ !

I If'

~ " I

/. .... •• . ..

~-/ I .......

/ i I I"

V I I

VI I

1 \ ~ I

! I \

I 1 -1 ' I I I

" I I I

I / T -Z I

I ....

I I I I i I 1

I I I 1~1, 5 104 2 5

RECIPROCAL PERIOD (a = liT) (sec-i)

Fig. 12. Peak Fission Rate as a Function of Reactor Reciprocal Period (HPRR).

20

The total fission yield and the yield in the "spike" of the burst

are shown as functions of reciprocal period in Fig. 13. The fission

yield in the spike of the burst was obtained by graphical integration of

the oscilloscope traces. In the higher yield burst; about 90% of the

fissions occur in the spike and 10% in the tail before the pressure waves

generated in the burst scram the system.

Acknowledgements

The burst detection equipment was made available by the N-2 Group

at Los Alamos Scientific Laboratory. The assistance of T. F. Wimett of

LAS:::', in the early phases of the experiment and in discussions of the re~

sults is acknowledged, Sulfur activations and counting were done by

E. B. Johnson, and fission product analyses by the Radiochemical Analysis

group under E. Wyatt. Co-workers in performing the experiments were

L. W. Gilley, Ay D. Callihan, J. J, Lynn, E. R, Rohrer, and J. F~ Ellis.

The work of J. R" Hill-*in reactor control maintenance is also acknow-

ledged.

*Instr-:.1IDen-taticm and Controls Di vi sion.

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o 10 ~---+--4-----~---~. -1 W

>= I(f)

a:: ::::> CD

2 3 4 5

RECIPROCAL PERIOD (a = 1fT) (sec-l)

Fig. 13. Total Fission and "Spike ff Yields as a Function of Reactor Reciprocal Period (HPRR).

22

A~endix!: Fission Yield Determination Data

The text has described the determination of fission yield from

measurements of the beta activity of irradiated sulfur pellets. These

pellets were 3.8 cm in diameter and 0.95 cm thick. Their orientations

with respect to the core are as shown in Fig. 4. The scintillation

counter used to measure the pellet activity had been calibrated in the

manner described by Reinhardt and Davis4 and by Hurst and Ritchie. 5

1Amere possible during the present experiments individual pellets were

counted both before and after burning, and the quoted flux is the aver

aee of the two counts.

'lIable A-l shows the results of five fission-product analyses used

to calibrate the sulfur activity in terms of the total fission yield.

In these runs fission yield was determined by exposing rods of alloy

in the irradiation hole of the reactor and radiochemically analyzing

the samples, after exposure, for fisSion-product activity. Barlum-140

production was used as the index in the fission-product determinations.

The number of fissions per unit flux was at points 0; 86, and 183 cm

from the reactor. It may be noted that at each position the maximum

spread of values is less than 20%. The average of these values shown

in the table were applied to the sulfur flux data of subsequent ru..l1S

to determine the fission yields given in Table A-2.

4. 5.

P. W. Reinhardt and F. J. Davis, Healt~ Physics, 1, 169-175 (1958). G. S. Hurst and R. H. Ritchie, Radiation Accidents: Dosimetric Aspects of, Neutron and Gamma-Ray E?g>0sure, ORNL-2748, Part A . (May, 1961).

*_4. Ba140 fission yield of 6 l~

".---- • lJ "'as Used,

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.. • • Table A-1. Calibration of Sulfur Pellets in

Terms of Fission Yield

Integrated Flux (n o cm-2 ) Fissions per unit Flux

Run Yield Position Position Position Position Position Position Number (fissions)* No. 1 No.2 No. 3 No. 1 No.2 No. 3

X 1016 X 1012 X 1010 X 109 X 10'3 X 105 X 106

0 1.96 3.94 5,48 8.25 4.96 3.57 2037

15 6.63 12.6 18.3 ·3 5. 3.62 2.05

36 5.60 9·36 .4 24.2 5.99 4.18 2.31

37 8.00 ·3 21.8 39·3 5.22 3.67 2.03

38 9.48 17.2 24.5 44.2 5. 3.87 2.11J.

Average 5.38 3.78 2.41

*Determined by radiochemical fission·.product analyses • ..

24

Table A-2. Fission Yields from Various Bursts, Determined from Sulfur Pellet Activations ..

Integrated Flux (n.cm-2) • Total Yield ..

Position 1 Position 2 Position 3 ( fissions)

x 10~2 x 10~o X 109 X .,

0.17 0.24 0.42 0.096

0.70 1.09 1.92 0.4:2

2.27 3.38 6.58 1.32 2.52 3.71 1. 2. 4.32 7·51 1.68

2·93 4. 7.68 1.69

3.37 4.89 7·50 1.8·4

3.58 5·20 9.47 2.06

3·99 5·37 9·73 2.18

4.31 5.94 9.90 2.3.3

5.34 7.78 13.0 2·99 5.45 7·67 14.1 3.08

5. 8.39 15·2 3.34 .. 6.01 8.60 15·6 3.4:2

7·15 10.1 18.0 4.J:L

7.46 10·9 4.

7· 11.8 4~6l

9.36 13.4 24,2 5·32

l:i··5 ·3 28.2. 6. 12.6 18.3 .2 .,

I •

·3 21.8 39·3 8.66

.9 22·9 42.4 9·1:5 17·2 .5 44.2 9·73 19~2 25.8 47.3 lCL 5 21.2 30.6 52.2 11.9

.8 30.6 57.6 12,,7 22.4 34.0 58.2 13·0 1

34.1 .9 " .. \"".

43.7 83.) 3

..

•

Appendix~: Oscilloscope Burst Traces

Traces of oscilloscope photographs for bursts ranging from

3.1 x 1016 fissions to 1.3 x 1017 fissions are presented on the follow

ing pages.

Total Yield Page No.

3.1 x 1016 fissions 26




9·7 x 1016 fissions 30

1.2 x 1017 fissions

1.3 x fissions 32

26


10~-----,------~-------,--------------~------,-------,---~·-.

~

~ 8 1-~--···~--'~--~-----4-···----_+-(.) en >... o ... :3 6 f-----~····-~II~ .. ---~ -I·--~---+---... o

w

PERIOD: 68,usee HALF -WIDTH: 250,usee PEAK RATE: 6.4 x 10 '9 fissions/sec

---... ~----i

~ 4f------~L-~----+----·~------_+----_r------~--~--+_----~ 0::

Z o (Ii

~ 2r-----~1--~~······~-------+~-----1-·----~-~-~--~-----~~~-----LL

500 1000 1500 2000 2500 3000 3500 4000 TIME (,usee)

.. ..

..

,

• ..

.'

,

w ~ a::: z 0 (f)

fQ u..

6

5

3

2

o o

I

J

/ /

// 200

f\ I

J ~

27

I I


I I TOTAL YIELD; 3.4 x 1016 fissions

PERIOD: 50 fLsec

HALF WIDTH: 177 fLsec

PEAK RATE: 8.9 x 1019 fis sions / sec

I

V \ I

\, \

\ "' N---

I i 400 600 800 1000

TIME (fLsec)

10

9

8

7

<U

C u

6 '" ;:-~

.Q 5 (;

w !;;:

4 a: z 0 Vi (/) 3 u:

2

50 100 150

28

200

PERIOD;


HALF -WIDTH: 87 fLsec

PEAK RATE: 5.5.1020 fissions/sec

INITATION OF SAFETY BLOCK

I

250 300 350 400 450

TIME (fLsec)

• •

,

• ..

• 111»

., •

'" 0 (J III

;:-,g :e 2 w ~ 0::

Z Q (f) (f)

L;:

5

4

3

2

0 0 50 100 150

29

200 TIME (fLsec)

250

UNCLASSIFIED ORNL-LR-DWG 676t5R

8.7 x lO t6 fissions

24 fLsec

71 fLsec 4.2 x !020

300 350 400

12

10

IV "5 0

'" i:::'

8

E 15 15 6 w !q a:: :z 4 0 (i) ~ u.

2

0 0

30

TOTAL YIELD: ---+-------1-1--\--+--- PERIOD:

50 100 150

HALF -WIDTH: PEAK RATE:

200

TIME (fl-sec)

250

UNCLASSIFIED ORNL-LR- DWG 67816R

9.7 x 10'6 fissions

22 fl-sec 65 fl-sec 6.8 x 1020 fissions/sec

300 350 400

• .. ..

• •

"

~2

10

E 0 0

; 8 g :e 0 6 w ~ Il: Z 4 Q (j)

• (j)

c;: 2

0

..

0 100 200

31

TOTAL YIELD, 1.2 x 1017 fISSIons

PERIOD, 19.4 fLsec

HALF - WIDTH; 58 fLsec

UNCLASSIFIED ORNL-LR- DWG 67811 R

PEAK RATE: 1.65 x 10 21 fissions/sec

300 400 500 TIME (fLsec)

., "0 u

'" ~ 4 I-------+------+----I--'-~---

~ :e o

W f<t £r


TOTAL YIELD: 1. 3 x 1017 fissions PERIOD; 21 "sec HALF- WIDTH: 58 "sec PEAK RATE; 8.1 x 1020 fissions I sec

~ 2~····-----+·········· --~~-----t---~--~------+-----T------+------+-----+(f) (f)

iJ::

O~~~~ ____ ~ ____ ~ ____ ~ ____ ~ __________ ~ ____ _L ____ ~

o tOO 200 TIME ("sec)

300 400

•

•

'.

... 1.

" 2" • 3·

4. ""'~ 5.

6. 7. 8.,

9,·18. 19· 20" 2l. 22. 23·

24-28. 29. 30" 3L )2. 33. 34. 35·

36-37. 58. 39· 40. 41-42. 1~3 • 44. 45.

lOt~' .. 106 ~ 107·

108-112.

11).·116.,

117-·118.

119· 120, .. 12l.

(' '122" 123.

124~

Jo J. E. R. To A. F. T. A. T. R. G. E. J. L •. E. R, D. S .. J. K. J. L. c. G" E. W. p" w. J., M.,

33

Internal Distribution

L. Anderson 46. J • J. Lynn A. Auxier 47. J. Do McLendon (Y-12) P. Blizard 48. H. Go MacPherson C. Block 49. D. W. Magnuson v. Blos.i3er 50. Fo C. Maienschein L. Boch 51-65. J. T. Mihalczo R, Bruce 66. K. Z. Morgan J. Burnett 67. F. J. Muckenthaler D. Callip.an 68 .. C. W. Nestor E. Cole 69. L. C. Oakes R. Coveyou 70. R. W. Peelle deSaussure 7l. A. M. Perry P. Epler 72. P. H. Pitkanen K. Fox 73· D. P. Roux W .. Gilley 74. E. G. Silver E. Gross 75,· M. J. Skinner G"\vin 76. M. L. Tobias C. Hamilton 77. D. R .. Ward H. Hanauer 78. A. M. Weinberg A. Harvey 79. F. G. Welfare (Y~12) M. Henry 800 W. Zobel R, Hill 81-83. Laboratory Records B., Holland 84. Laboratory Records, ORNL R.C, F. Holloway 85-86. Central Research Library r:< Hurst 87. Docu~cnt Reference Section u,

B. Johnson 88, Research and Development H. Jordan Di vision} ORD R. Kasten 89";103. Division of Technieal Informa-E. Kinney tion Extension, liIE A. Lane L Lundin

External, .Distribution

United Nuclear Corporation, White Plains, New York J. R. Beyster; General Atomic, San DlegoJ California H. C, Paxton, G. E. Hansen, C. B. MillS, W .. Ro Stratton, and T. F. Wimett; Los Alamos Scientific Laboratory, Los Alamos, New Mexico J. E. Carothers, E. H. Cristie, q. E. Cummings, and O. C, Kolar; Universi.ty of California, Lawrence Radiation Laboratory, Livermore, California D. M. Ellett and P. D. OiBrien; Sandia Corporation, Albuquerque, New Mexico C. L. Schuskej Dow Chemical Company, Rocky Flats, Colorado E, O. Baicy, U .. S. Army Ordnance Ballistics .Laboratory, Aberdeen Proving Grounds, Aberdeen, Maryland G. E, Elder; White Sands Nissile Range, White Sands, New Mexico A. Lo Kaplan; General Electric Corp, Syracuse, New York

E. D. Clayton; General Electric Company, Hanford Laboratories, Richland, Washington

Do ~Jood.; AlbuqUerque Opel~ations Office, Atomic Energy COl1ITuission, Albuquerque, New Mexico

• II ,

Documents

Uranium 01