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STRUCTURAL INTEGRITY INVESTIGATIONS OFFEEDER PIPE ICE PLUGGING PROCEDURES
Report No 84-462-K
M.T. Flaman - Unit Head - ExperimentalStress Analysis
N.N. Shah - TechnologistApplied Structural and Solid Mechanics
SectionMechanical Research Department
91602new 82-10
Ontario hydroresearch division
STRUCTURAL INTEGRITY INVESTIGATIONS OFFEEDER PIPE ICE PLUGGING PROCEDURES
Report No 84-462-K
M.T. Flaman - Unit Head - ExperimentalStress Analysis
N.N. Shah - TechnologistApplied Structural and Solid Mechanics
SectionMechanical Research Department
ABSTRACT
A procedure involving tlv use of a liquid nitrogencooled heat exchanger to form internal ice plugs infeeder pipes is routinely used in nuclear generatingstations. The use of this procedure has causedconcerns with regard to the safety of stationmaintenance personnel, and in regard to the integrityof the feeder pipes. This report describes theresults of laboratory stress and pressure measurementswhich were performed on a feeder pipe section duringice plugging operations to investigate theseconcerns. From the results of this study, and fromthe results of previous studies of material behaviourat low temperatures, it has been determined that theice plugging procedure can be performed on feederpipes in a safe and effective manner.
job
740621-159-451
Me
825.22 March 21, 1985ftopon no.
84-462-K
9160?new 82-10
Ontario hydroresearch division
FXFCUTIVF SUMMARY
STRUCTURAL INTEGRITY INVESTIGATION OF FEEDERPIPE ICE PLUGGING PROCEDUPFS
M..T. Flaman and N.N. ShahApplied Structural and Solid Mechanics Section
Mechanical Research Department
A routine procedure in nuclear generating stations involves thecreation of internal ice plugs in feeder pipes to temporarilyisolate fuel channels. In this procedure a heat exchanger islocated around the water-filled pipe at the position where theblockage is to be made. Then, the heat exchanger (or "jacket")is filled wit), liquid nitrogen (-196CC) causing heat to beremoved from the pipe and an ice plug to form.
Based upon the significant reduction in fracture toughness ofthe feeder pipe steel at low temperatures, it was determinedthat even very small flaws in the pipe could result in a catas-trophic pipe failure, due to high stresses which were thoughtpossible to occur during ice plugging. This report investigatedstructural concerns of the ice plugging procedures through theperformance of tests involving the measurements of stresses,temperatures, pressures and forces relating to the integrity ofthe pipe and of the ice plug.
From the results of this study combined with materials behaviourdata, it has been determined that:
1. Maximum tensile stresses in feeder pipes due to the iceplugging procedure are not excessive in relation to permis-sible flaw sizes and material behaviour at low temperatures.
2. The ice plugging procedure can be safely performed withlittle possibility of immediate or delayed damage to thefeeder pipe.
3. Properly formed ice plugs can safely resist high differen- J
tial water pressures with negligible chance of water leakagepast the plug or of plug slippage.
740621-159-451 825.22March 21, 1985
""W-4 6 2-K
TABLE OF CONTENTS
Page
1.0 BACKGROUND 1
2.0 TEST APPARATUS 1
3.0 TEST RESULTS 2
4.0 DISCUSSION 14
5.0 CONCLUSIONS 15
REFERENCES 16
APPENDIX A STRESSES AND TEMPERATURE DURING FORMATIONAND MELTING OF ICE PLUG 17
DISTRIBUTION last page
- i - 84-462
LIST OF FIGURES
r 'C'JRV. n Location of Strain Gauges/TemperatureSensors on Feeder Pipe Test Specimen
FIGURE 2 Pictures of the Test Apparatus
FIGURE 3 Stress Vs Time at Maximum Stress Location
FIGURE 4 Stress Vs Temperature at Maximum StressLocation
FIGURE 5 Stress Measurement Due to HydrostaticPressure Tests Against Fully FormedIce Plug
FIGURE 6 Stress/Pressure Changes Due to "Trapped"Water During Ice Play Formula.
FIGURE 7 Results of Attempts to Dislodge Ice Plug
Page
3
4
6
10
13
- ii - 84-462
91GH1now b? W
Ontario hydroresearch division
To Mr. B. Mont fordManager-Chemistry & MetallurayNuclear Generation Division
Mr. D.W. SoutherManager - Nuclear Systems D<=ptDesign & Development Division
STRUCTURAL INTEGRITY INVESTIGATIONS OF ICE PLUGGINGPROCEDURES _ON_FE_EDEK__P̂ PE_S
1 .0 BACKGROUND
In nuclear generating stations, a routine procedure to temporar-ily block water filled feeder pipes involves the formation of aninternal ice plug. In this procedure, an annular jacket isplaced around the pipe, and the jacket is then filled withliquid nitrogen (-196°C). The removal of heat from the pipe atthe location of the jacket causes a solid ice plug to formwithin the pipe.
Due to the possibility of high stresses which may arise in thepipe steel during the plugging procedure, combined with theexistence of material flaws and the reduction in fracture tough-ness of the feeder pipe material at liquid nitrogen tempera-tures, concerns have been expressed as to the safety of the iceplugging procedure.
These concerns relate to: the capability of the pipe to accom-modate the thermal and mechanical stresses caused by thetemperature changes of the pipe and the interaction with the iceplug; the long-term serviceability of the pipe due to possibleundetected damage incurred during ice plugging; and; the abilityof the ice plug to resist leaking or dislodging due to hydro-static pressure.
A series of laboratory experiments were recently carried out onan instrumented feeder pipe to document various physical pheno-mena which relate to the safety of this procedure for routinenuclear plant maintenance requirements.
2.0 TEST APPARATUS
A 2 m long 3.5 inch feeder pipe section from Bruce NGS 'A' wasobtained for testing requirements. One end cap was welded tothe bottom of the pipe while the top was left uncapped. (The
- 1 - 84-462
pipe was in the vertical position for all tests). Special cryo-genic strain gauges and temperature sensors/l/ were attached tothe external surface of the pipe at various locations, as shownin Figure 1 on the following page. A single wall ice pluggingjacket was positioned at about mid-section of the pipe. Assuch, some of the strain gauges were within the boundary of thejacket (exposed directly to the liquid nitrogen) while othergauges were located at various positions below the jacket loca-tion .
At the bottom of the pipe, a tap was located to provide ahydraulic connection to the water within the pipe. (For sometests, an electronic pressure gauge was attached to monitorincreases in water pressue due to the ice plug formation. Forother tests, a "manometer" line was connected to this tap tomaintain water level within the pipe, and to ensure that waterpressure in the lower part of the pipe could not increase duringthe formation of the ice plug).
All instrumentation was connected to a computer-controlled dataacquisition system. Extensive calibration tests were performedbefore actual testing to verify that all measurement equipmentwas functioning properly. When al 1 aspects of the measurementequipment were fully demonstrated to be accurate and reli-able/2, 3/, the tests were peformed. Pictures of the testapparatus are shown in Figure 2 on page 4.
3.0 TEST RESULTS
3.1 Ice Plugging With No Fluid Pressure Increase
In the first series of tests, the "nanometer" was attached tothe bottom of the pipe and no pressure boundaries were locatedat either the top of the pipe or the top of the manometer waterline. This ensured that no fluid pressure (other than a hydro-static head of about 2 m) could build up at the bottom of thepipe during the formation or melting of vhe ice plug.
As such, these tests were to investigate the increase in stressin the outside surface of the pipe due to the combination ofpipe thermal stresses and mechanical interaction stresses causedby the formation/melting of the ice plug.
Of immediate interest are the stresses at the specific straingauge location which indicated the maximum tensile stresschanges. This location was inside the cooling jacket withinabout 10 nun of the lower boundary of the jacket (Location #3).In this area, the exterior surface of the pipe is in directcontact with the liquid nitrogen.
- 2 - 84-462
IIIIIIIII
#4 Rosette at 270°
J Inside Bottom Edge of the Jacket
iiIIIIiII
LN2 Jacket
02 Rosette at 270°
'at 180°, #11 at O°and $12 at 270°Sat 180°. #7 at 0° and #8 at 270°-
#1* Rosette at 270'
2500
<r\
_r20
1260
Jt
WO
1-20
PressureTransducer
Feeder Pipeheld in VerticlalPosition
- -70
'-ManometerLine
TransducerDisconnectValve
-ManometerDisconnect Valve
'Drain Valve
FIGURE 1
LOCATION OF STRAIN GAUGES/TEMPERATURE SENSORS ONFEEDER PIPE TEST SECTION
- 3 - 165924-RD
Shown on the following page {in Figure 3) is the entire history(stress vs time) of the stress changes at highest recordedstress location during both plug formation and during plugmelti ng.
Within a short time of introducing the liquid nitrogen into thejacket, the material on the external surface became stressed intension to about 100 MPa . (The yield strength of the pipe atroor;; temperature is greater than 400 Mi's; near liquid nitrogentemperatures, the yield stress would exceed 1000 Ml'a). Thisvalue of 100 Ml'a is the maximum tensile stress for this test 'that was experienced at this location during the ei.tire forma-tion and melting of the ice pli'g. This maximum tensile stressat this location occurred at a temperature of about -!50'C.Complete stress vs temperature data for this strain qauge posi-tion is shown in figure 4 on page 7.
After reaching this peak magnitude, the stress at this rosetteposition quickly dropped to very lo*1 levels and never subse-quently exceeded ?0 MPa during the remaining formation ormelting of the ice plug.
Entire graphs for all rosette positions are included for thistest in Appendix 'A'. This appendix includes graphs of "stresjvs time", "stress vs temperature" and "temperature vs time" forall strain gauge rosette positions.
In general, the following have been observed for these tests:
1) Maximum pipe stresses are tensile, occur close to the boun-dary of the jacket, and ?.'wjys occur during ice plug forma-tion.
2) Stresses are higher within the jacket than areas outside ofthe jacket.
3) During plug formation, the rise of the maximum stress ateach rosette position occurs sequentially with time (as theplug "grows" past each rosette).
4) The rate of stress increase or decrease at any point on thepipe is generally proportional to the proximity of the pointto the jacket flanges.
The maximum stress changes varied from test to test by asmuch as 50 MPa, even for nominally identical test condi-tions. Therefore, it is statistically possible that somwhathigher stresses could occur at this location if many moretests were performed.
- 5 - 84-462
ROSElTt • 3
STRESS VS. TIME DURING PLUG FORMRTION
w 60- -
to 4B- -
* Rosette 93 is just v.'ithin Freezing Jockstabout 30 mm above Jacket Lower Flange TIME (HOURS)
5 SB- -
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ROSETTE « 3
STRESS VS. TIME DURING PLUG MELTING
- 2B - - TIME CHOURS)
Fl ' JRE 3
STRESS VS TlfviE AT MAXIMUM STRESS LOCATION(NO WATER PRESSURE ALLOWED TO BUILD UP IN TEST PIPE)
- 6 -165928-RD
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STRESS
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EMPERRTURE DURING PLUG FORMRTION
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STRESS VS. TEMPERRTURE DURING PLUG MELTING
TEMP. CDEG C)
FIGURE H
STRESS VS TEMPERATURE ATMAXIfJUM STRESS LOCATION(NO WATER PRESSURE ALLOV.ED TO BUILD UP IN TEST PIPE)
- 7 - 165929-RD
5) During ice plug melting, low compressive stress magnitudes(< 50 MPa) would generally occur at each measurement posi-tion .
6) From an analysis at a number of nominally identical tests,there is a significant variability in stress changes(±50 MPa) from test to test, and from one rosette locationto another rosette location on the same circumference.
3.2 Stress Changes at Each MeasurementPosition Due to SubsequentPressurization Against Fully Formed Ice Plug
At the completion of a fully formed ice plug (at which t irr.estrains and temperatures were seen to stabilize at all rosettepositions) a simulation of a station hydrostatic test was per-formed to observe the stress changes in the pipe due to thisprocedure. (This test would also simulate the reduction ofpressure on one side of the ice plug which was initially formedin a pressurized pipe)•
In this test, fluid pressure was increased in increments ofabout 7 MPa using a manual pump connected to the tap at thebottom of the pipe. The only stress changes that were detectedwere from the rosette at the extrene bottom of the pipe (wherethe water was always in the liquid state). These stress changes(cor Posette 15) are shown in Figure 5 on the next page and areprecisely equal to the stresses that would be produced frompurely fluid pressure effects. No stress changes were observedat any of the other rosette positions as shown for the nextrosette nearest the pipe bottom, Rosette 14. (Thisrosette (#14) "covers" the ice plug).
3.3 "Trapped" Water Pressure IncreaseDue to Ice Plug Formation
In this test, the tap on the bottom of the pipe was closed. Apressure gauge, however, was connected hydraulically to the pipeto record changes in fluid pressure due to plug formation andmelting. A graph of the pressure increase vs time is shown inFigure 6.
This test would simulate the situation Where an ice plug wasformed near a closed valve or near a previously formed ice plug.
The maximum stresses at all locations covering the ice plug werenot significantly different in this test from the previous testin which there was no fluid pressure increase. As shown inFigure 1, on page 3, nearly all of the strain gauges are locatedin the area of the ice plugging device.
~ 8 ~ 84-462
100- -
8 0 - -
60--
40<
2 0 "
Rosette #74Stress Measurements a! Location 1015 mmabove Pipe Bottom (Adjacent to end of Ice Plug I
5.0 10.0 15.0 | 15.0Peak Pressure (20.7 MPa)
10.0 5.0 0
Water Pressure(MPa)
c
100-f-
8 0 - -
6 0 - -
4 0 - -
Rosette #15Stress Measurements at 390 mm above Pipe Bottom
(Adjacent to Liquid Water)
5.0 10.0 15.0 \ 15.0 10.0 5.0 0(Peak Pressure 20.7 MPa)Water P r e s s u r e ( M P a )
FIGURE 5
STRESS MEASUREMENTS DUE TO HYDROSTATIC PRESSURE TESTSAGAINST FULLY FORMED ICE PLUG
- 9 765930-RD
Rosette ~15 (below Ice Plug, 3yu mmabove Pipe Bottom/
rv—*==TtHE CHINUT
"TEST 6"
Water Pressure at Pipe Bottom Not Allowed to IncreaseDuring Plug Formation (Manometer Used I
Maximum Stress(Circumferential)
Minimum Stress (Axial I"TEST 7"
Water Pressure at Pipe Bottom Allowed to Build upDuring Plug Formation (Bottom Valve Closed)
Trapped WaterPressure
"TEST 7"
Pressure Changes at Pipe Bottom During Plug FormationDue to "Trapped" Water (Test 7)
FIGURE 6
STRESS/PRESSURE CHANCES DUE TO "TRAPPED" WATERDURING ICE PLUG FORMATION
- 10 -165931-RD
The only major difference in maximum stress changes between thetest in which there was trapped water and the test where thewater pressure was not allowed to increase was for the rosetteat the pipe bottom (where ice did not form). Only in this areawas there seen to be proportional increases in pipe stresses dueto the increases in pressure of the (trapped) fluid.
It should be noted that there was a relatively large column oftrapped water below the ice plug. Therefore, it is clear thatfluid pressure increases in the trapped water would be higher ifthe plug had been formed closer to the pipe bottom (ie, if theamount of trapped water were smaller).
3.4 Tests to Determine MaterialDamage Due to Ice Plugging Procedure
Of direct concern to pipe integrity is the possible occurrenceof undetected pipe damage during the ice plugging procedure.This damage would be manifested in a permanent change in stressor strain in the pipe material due to the performance of a plug-ging operation.
If this were to occur on station feeder pipes, then such damage,if severe, might lead to a catastrophic rupture during subse-quent unit operation. Additionally/ even if such damage isrelatively slight, it could be cumulative due to repeated iceplugging operations at the same location. This cumulative dam-age could lead to a subsequent in-service failure or it couldlead to a failure during a subsequent ice plugging operation.
With regard to all of the previous tests, the net change at thestrain gauge locations due to the formation and melting of theice plug was closely monitored. It was observed that no mate-rial yielding took place due to any of these previous tests.This indicates that the ice plugging operation could not producepermanent "damage" on feeder pipes. A typical example is theresult of one test, shown in Table 1, on page 12.
This result (which shows no net stress changes due to a pluggingoperation) is consistent with the measurements taken during theplugging procedure. This is because yield stress was never seento be exceeded during the formation or melting of the i-.-e plug.As such, permanent material deformations would not have beenexpected to occur from this procedure due to low stress measure-ments obtained during ice plugging operations.
In these tests, no significant defects existed at the area ofthe ice plug. From tests and analyses performed elsewhere/6/ ithas been determined that there is very little risk of pipe rup-ture or damage even when "large" and otherwise unacceptabledefects might exist in the pipe.
- 11 - 84-462
TAOLC r
MAXIMUM AND RESIDUAL STRESS DURING AND AFTERICE PLUGGING TEST
{Ho pressure was allowed to build up in the lower end of the pipe}
fiusctluNo
1
2
3
it
5
6
/
S
9
10
It
12
13
11
15
Stress Beforelee Plugging
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0.00
0. 00
0. 00
0.00
0.00
0. 00
0. 00
0. 00
0.00
0. 00
0.00
0. 00
0. 00
0. 00
0. 00
Maximum stressDuring tee Plug
Formation t MeltingMPa
78.05
50. 68
103. 12
107. 56
32. 13
27. 11
70. 69
64.05
52. 05
16. i «
19. 5tf
28.68
19.65
21. «4
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Remaining StressAflcr Ice Plug
Fully MeltedMPa
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-0. 76
0. 62
*
- 1. 52
1. SS
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3. 71
- I . 79
- ; . 31
-3. 31
- I . 52
- I . 21
-0. 55
-0. 21
' Verified Strum Cage Failure
165923-KO
3.5 Ice Plug Dislodging Tests
The final test in this study involved an attempt to dislodge theice plug to determine the general integrity of the plug and todetermine a margin of safety during hydrostatic tests.
In this test, an ice plug was allowed to fully form as in theprevious tests and then the water pressure at the bottom of thepipe was increased in steps. A graph of fluid pressure vs pipestress change (at the bottom of the pipe) is shown on the nextpage in Figure 7.
At about 70 MPa fluid pressure, the strain gauge readings beganto deviate from a linear response (to pressure), and this indi-cated that some material yielding had begun to take place atthis pressure. The indicated circumferential pipe stress atthis pressure was about 415 MPa.
- 12 - 84-462
1'iiinl ul whu I)
Strum innitii I in',- •(/
Plot of Mulct- Pressure \ s I'I/'V blress Dunn./ Ue Pluu DisUnlt/m./ Tests
PressureTop
Location
Photograph of Fractured Section of Feeder Pipe due toPrcssuri/ation aijuinst Ice Plug
FIGURE 7
RESULTS OF ATTEMPTS TO DISLODGE ICE PLUG
- 13 -165932-RD
At about 75 MPa fluid pressure, extreme yielding beqan to occurin the pipe steel as proportionally more fluid was bpinn(manually) punped into the pipe with relatively small increasesin fluid pressure (no fluid leakage was observed from the pipeor test apparatus). The strain gauges failed at this point dueto excessive1 elonoation).
At. each .stage o<" the testing during pressur i zat i on, manualpressurization was halted while the stability of the pressureoauqe was observed. At each stage, the pressure was seen toremain steady indicating that:
the plug was not slipping: and,water was not escaping past the ice plug or through faultypip^ fittings or cracks.
i)ii)
fittings or cracks
At approximately BO MPa fluid pressure, the pipe suddenlyburst. ("Jornal operating pressure is about 10 MPa). The burstpoint occurred at the pressure tap location?, near the pipehot to.-i.
A picture o f the burst section (which has been severely de-formed) and pressurization data is shown in Figure 7.
4.0 .DISCUSSION
From all of the tests performed on this feeder pipe, it isclearly indicated that the ice plugging procedure can he per-formed safely and effectively. However, it must be noted thatno parametric studies were performed (on different sizes ofpipes, or with various cooling durations, etc). As such theresults of these tests must be applied with caution to other iceplugging situations which do not duplicate the test conditions.
However, considering the relatively low magnitude of stressesthat were measured in these tests, it is very likely that iceplugging operations can be safely performed in larger or smallerpipe diameters.
The concern regarding the ice plugging procedure involves thecombined effects of stress, materials behaviour at low tempera-ture and the occurrence of flaws in the feeder pipe steel .Previous studies/4,5,6/ have shown that because of therelatively low stresses involved with this procedure, there isnegligible likelihood that even "large" flaws in service pipingwill initiate, or propogate due to the ice plugging procedure.
- 14 - 84-462
5.0 CONCLUSIONS
1) Ice plugging operations on feeder pipes can safely beperformed (if no fluid pressure increases are allowed tooccur).
ii) In constrained conditions, where water can be trapped bythe ice plug, the use of the ice plugging procedure cancause excessive pipe stresses to occur.
iii) No permanent pipe damage was detected to result from theice plugging procedure.
iv) Properly formed ice plugs are shown to easily resistdifferential fluid pressures equal to the nominal operat-ing pressure of the feeder pipe.
v) Taking into account the low measured stresses, previousstudies would indicate that there would be negligiblechance of even "large" flaws in feeder pipe propogatingdue to the ice plugging procedure.
ACKNOWLEDGEMENTS
We wish to thanV. Mr. Ivan Pomakov for his assistance in thisproject and for supplying us with the ice plugging _pparatus.Also, we appreciate the efforts and advice of Mr. R. Lyons, andDr. P.C. Lichtenberger for their support and advice in thisproject.
Approved: Submitted:
G.J. ClarkeManagerMechanical Research Dept
M.T. FlamanUnit Head - ExperimentalStress Analysis
Applied Structural & SolidMechanics Section
N.N. ShahTechnologistApplied Structural 5. Solid
Mechanics Section
MTF/NNS:! jh
- 15 - 84-462
REFERENCES
1. "Strain Gauges in Cryogenic Environment", John C. Telinde,Experimental Mechanics, September 1970.
2. "Feasibility Study on Determining Stresses on a NitrogenCooled Pipe: Progress Report", M.T. Flaman, September 7,1979.
3. "Status Report on the Qualification Study of The Feeder PipeIce Plugging Procedure", M.T. Flaman, Report No 81-491-K,January 1, 1982.
4. "Summary of Results from Fracture Toughness Work on A106BWelded Pipe", J.C. Thornley, NBRPC, September 12, 1978.
5. "Metallurgical Evaluation of Ice Plug Practices", Memo toP.C. Lichnenberger from A.M. Pritchard (File No N-04910.1),March 20, 1984.
6. "Phase I Development of Guidelines for Use of Ice Plugs inPipeline Maintenance and Hydrostatuc Testing", November 15,1982, J.F. Kiefner, et al, Battelle Columbus Laboratories,Columbus, OH.
- 16 - 84-462
ROSETTE # 1
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- 19 - 84-462
STRESS VS. TIME DURING PLUG FORMRTION
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- 20 - 84-462
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- 21 - 84-462
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- 22 - 84-462
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- 23 - 84-462
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- 24 - 84-462
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- 2 5 - 84-462
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- 26 - 84-462
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- 27 - 84-462
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- 28 - 84-462
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- 29 - 84-462
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-30 - 84-462
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- 32 - 84-462
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- 33 - 84-462
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- 36 - 84-462
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- 39 - 84-462
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ROSETTE
STRESS V5. TEMPERflTURE DURING PLUG FORMRTION
TEMP CDEG C)
* 6
80- %
(0*
M 604-
20- -
-28- -
STRESS VS. TEMPERflTURE DURING PLUG MELTING
TEMP CDEG C)
- 40 - 84-462
8B--
-20--
ROSCTTE • 7
STRESS VS. TEMPERRTURE DURING PLUG FORMRTION
TEMP CDEG C)
80- r.
60- -
40- -
20--
STRESS VS. TEMPERRTURE DURING PLUG MELTING
- 41 - 84-462
i
-E0--
STRESS VS. TEMPERHTURE DURING PLUG FORMRTTON
TEMP CDETG C)
8B--
60--
STRESS VS. TEMPERflTURE DURING PLUG MELTING
- 42 - 84-462
% 80
iin
6B--
-20--
STRESS V5. TEMPERRTURE DURING PLUG FORMRTION
TEMP IDEG C)
"R3SCTTTT-5
60--
S 60+
40- -
20- -
-20- -
STRESS VS. TEMPERflTURE DURING PLUG MELTING
TEMP (OES C)
- 43 - 84-462
t80--
6 0 - -
X
in 40--nc0
20- -
- 2 0 - -
ROSETrTE • IB
STRESS VS. TEMPERflTURE DURING PLUG FORMRTION
TEMP CDEG C)
STRESS VS. TEMPERflTURE DURING PLUG MELTING
-17V -158 -1̂ 5 f̂fe =78
- 44 - 84-462
80--
GB--
U) 4 0 - -nj*.
n2 B - -
-20--
ROSETTE # 11
STRESS VS. TEMPERHTURE DURING PLUG FORMRTION
TEMP CDEG C)
80- -„
i 60-1-
48--
28-.
-28--
KQafcITfc. • 11
STRESS VS. TEMPERRTURE DURING PLUG MELTING
TEMP CDEG C)
- 45 - 84-462
S BB
S BB
-20-
STRESS VS. TEMPERRTURE DURING PLUG FORMRTION
TEMP CDEG C)
28--
-2B--
STRESS VS. TEMPERRTURE DURING PLUG MELTING
TEMP <DEC C)
- 46 - 84-462
60--
x
jjj 4 0 +
20--
-2B--
STRESS VS. TEMPERRTURE DURING PLUG FORMRTION
-175 ^TSB ::Tl5-—
TEMP (DEG C)
80--
60- -
40. .
28--
-2B--
STRESS VS. TEMPERflTURE DURING PLUG MELTING
- i?5 =IaB
TEMP CDEG C)
- 47 - 84-462
B0- -,
6 0 - -
in 4B<3n
20- -
ROSETTE • I T
STRESS VS. TEMPERHTURE DURING PLUG FORMRTION
s ^
- 2 0 - -TErF> tDETG C)
U)
5 BB- -
60--
- 2 B - -
STRESS VS. TEMPERflTURE DURING PLUG MELTING
TEMP (DEC C)
- 48 - 84-462
E BB-"
6 8 - -
I)2 0 - -
"ROSCTTE • " I s "
STRESS VS. TEMPERHTURE DURING PLUG FORMRTION
=56
- 2 0 - -TEJP CDEG CJ
* 15
STRESS VS. TEMPERBTURE DURING PLUG MELTING
68--
40--
8B--
-17 T5 =T
-28- - TEMP CDEG C)
84-462
TEMPERRTURE VS. TIME DURING PLUG FORMRTION
»JBTItg (HOURS)
TEMPERRTURE VS. TIME DURING PLUG MELTING
i i i i—ife—*- ibTIME (HOURS?
- 51 - 84-462
TEMPERRTURE VS. TIME DURING PLUG FORMRTION
1J4TIME (HOURS)
KOSLIIt *
TEMPERRTURE VS. TIME DURING PLUG MELTING
i 1 i—ifa ifeTIME CHOURS)
- 52 - 84-462
TEMPERRTURE VS. TIME DURING PLUG FORMRTION
-aee- .fe .b tJe i ) 4
TIME (HOURS)
TEMPERRTURE VS. TIME DURING PLUG MELTING
- 53 - 84-462
-5B- -
• 4TEMPERRTURE VS. TIME DURING PLUG FORMRTION
Jk M M 1J2TIKE (HOURS)
TEMPERRTURE VS. TIME DURING PLUG MELTING
IB II XH IB IB
- 54 - 84-462
TEMPERflTURE VS. TIME DURING PLUG FORMHTION
t * * i f rii TieTIME (HOURS)
ROSETTE # 5
TEMPERRTURE VS. TIME DURING PLUG MELTING
* - ^ t i i ife—ik—ifeTIME CHOURS)
- 55 - 84-462
TEMPERRTURE VS. TIME DURING PLUG FORMRTION
iT4 TIB
TIME (HOURS)
u
» 25TEMPERRTURE VS. TIME DURING PLUG MELTING
i iTIME (HOURS)
- 56 - 84-462
TEMPERRTURE VS. TIME DURING PLUG FORMRTION
TU—dBTirC (HOURS)
u
a 25
HOSLT1L 4 V |
TEMPERRTURE VS. TIME DURING PLUG MELTING
t—i—ib—ale—A - * •
TIME (HOURS)
- 57 - 84-462
23--
B- -
: -25
I-5B
-75
-IBB
-125-
-15B-
-175-
-aaa
TEMPERflTURE VS. TIME DURING PLUG FORMRTION
T i l TM iTl
TIME (HOURS)
TEMPERHTURE VS. TIME DURING PLUG
- 58 - 84-462
TEMPERRTURE VS. TIME DURING PLUG FORMRTION
TEMPERRTURE VS. TIME DURING PLUG MELTING
i i * i &—ft—A—its—ifa—rirTI fE (HOURS)
- 59 - 84-462
TEMPERHTURE VS. TIME DURING PLUG FORMflTION
TEMPERRTURE VS. TIME DURING PLUG MELTING
i i i 1 ife—rfe ife—ife—gfe-TlfEtHOURSJ
- 60 - 84-462
a 25
0
T -25"
-5B-
-75-
-ZB0-
-125-
-15B-
-175-
-aae
rTEMPERRTURE VS. TIME DURING PLUG FORMHTION
ik 1 it* IJETIfg (HOURS)
TEMPERRTURE VS. TIME DURING PLUG MELTING
* i i i—ife—ife—A—ATIME (HOURS)
- 61 - 84-462
o
6 25
B- -
E ~Z5i
-SB-
-75-
-180-
-125-
-15B-
-175-
-888-
TEMPERRTURE VS. TIME DURING PLUG FORMRTION
—risTIME (HOURS)
TEMPERRTURE VS. TIME DURING PLUG MELTING
- 62 - 84-462
u
Id 25
B--
-50-
-75-
-100-
-125-
-I5B-
-175-
-aea-
TEMPERRTURE VS. TIME DURING PLUG FORMRTION
A 1 Hi rh rirTIME (HOURS)
»' 25--
* 13
TEMPERRTURE VS. TIME DURING PLUG MELTING
-i i i i ik «fe—*-TIME (HOURS)
- 63 - 84-462
to 25
i
r - 2 5 - -
-58- -
-75- -
-100--
- 1 2 5 - -
-150- -
-175- -
-aaa
» 14
TEMPERRTURE VS. TIME DURING PLUG FORMRTION
rhr1J2
TI(C (HOURS)
u
a 25
B- -
TEMPERRTURE VS. TIME DURING PLUG MELTING
•i i—i i A—ib * -tHOURS)
- 64 - 84-462