ML20236J291
| ML20236J291 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 10/30/1987 |
| From: | PUBLIC SERVICE CO. OF COLORADO |
| To: | |
| Shared Package | |
| ML20236J278 | List: |
| References | |
| NUDOCS 8711050247 | |
| Download: ML20236J291 (56) | |
Text
{{#Wiki_filter:_ .. - - - .- 3 r ) lf PRELIMINARY REPORT ON THE IMPACT OF THE FSV a OCTOBER 2ND FIRE i 1 d l OCTOBER 30.1987 i i
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1' E FORT ST. VRAIN NUCLEARGEERATING STATION i PUBUC SERYlCECOMPANYOF COLORADO l 1 h[k kDbbK $7 S
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I i TABLE OF CONTENTS Page ) l 1.0' PURP0SE.............................. . ..... . ............ 3
- 2.0 CHRON0 LOGY OF EVENT AND TRANSIENT....... ... .. .......... . 4 3.0 -ROOT CAUSE OF HYORAULIC OIL FIRE DETERMINATION .... .... ... 5
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J 3.1 Hydraulic System Description ............ ............. 5 j 3.2 HV-2292 Inspection Results .. ......................... 6 i 1 3.2.1 011 F i l t e r C a n i s t e r . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 i l 3.2.2 Flange /0-Ring ...... ............. ............. 6 l l 3.2.3 Thermal Relief Valve............ . ..... ..... 7 ' 3.3 Ignition Source.... ....... . .... . . ..... .. . .7 1 3.4 Root Cause Conclusion... .... .. ....., ....... 8
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4.0 FIRE MODEL DETERMINATION .. . .. . .. ,, 9 5.0 EQUIPMENT DAMAGE ASSESSMENT...... ...... ... . . ... ........ 10 6.0 DETERMINATION OF ROOT CAUSE FOR CONTROL ROOM SMOKE INGRESS .. 12 6.1 System Description . ...... ........................... 12 t 6.2 Operator Statements.. ............ ................. . 14 6.3 Conclusions........... ..... . ...... ...... ........ .14 7.0 ROOT CAU S E FOR ' C ' C I RCU LATOR TRI P . . . . . . . . . . . . . . . . . . . . . . . . . . 19 l ' ! 8.0 FIRE DETECTION AND ANNUNCIATION SYSTEM . . ... .... .... 20 8.1 System Description . . . . .... ..... ... ............. 20 8.2 Equipment Inoperable Prior To Fire . .. ......... . 21 l ! P I
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Page 2 of 26 i Page LL 9.0 LICENSING ASSESSMENT .... .. ...... . .... .. ..... ...... .. 22 9.1 Appendix'R' Determinations...... .. .... ............... 22 ' 9.2 Appendix A Determinations......... ... ................ 22 i 9.3 Control Room. Habitability....................... .. .. 23 ] 9.4' Hydraulic Oil Leakage Technical Specification. . . . . . . . . . 23 9 '. 5 Overall Hydraulic System Assessment................... .23 4
-10.0 ACTION ITEMS .... 4 ....................................... .. 24 ,
10.1 Prior To Rise To Power ......................... ...... 24 e 10.2 Next Steps ...... .......... .......... .. .......... 24 l 11.0' CONCLUSION ...... . . .. ... ..... .. . ...... ........ ... 25 r 1
12.0 REFERENCES
AND APPENDIXES.... . .......... ..... ......... .. 26 l
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Page 3 of 26' 1.0 PURPOSE i h The purpose 1'nis' report is to provide preliminary information l relative to s..e damage. incurred during the fire at the Fort St. Vrain Nuclear Generating Station on October 2-3, 1987. The root cause of.the fire has been determined as have near and longer 4 term action items designed to preclude the oc:urrence of this event and to enhance the safe operation of the plant. I i F. l i 1
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_r_______ y Page 4 of 26 2.0 CHRONOLOGY OF EVENT AND TRANSIENT The plant was being prepared to place the turbine on line. The reactor was at 27% power and Loop I was on the main steam bypass - control. The Reactor Operator (RO) placed the Loop II main steam bypass control in Auto to close HV-2292 and noted a drop in hydraulic pressure. An Equipment Operator (EO) was dispatched to investigate. The E0 found a hydraulic leak and a ; small fire at HV-2292. The fire was extinguished, but while the E0 was reporting the situation to the control room, the fire reignited. The Fire Brigade was summoned to fight the fire. Another E0 was dispatched to isulate the hydraulics to Group 1 on Loop II of System 91. SV-2212, 'O' Circulator speed valve, and HV-2253, Loop I reheat block valve are also in this group. The R0 placed 'C' Circulator speed controller in manual and began decreasing 'O' Circulator speed while increasing 'C' Circulator speed to maintain steam temperatures in preparation of isolating the hydraulics. At 0006:22, 'C' Circulator tripped on fixed high speed. Plots show a substantial increase in cold reheat pressure at this time. Apparently, fire affected the main steam bypass control valves causing one or more of them to go open, resulting in an l increase in cold reheat pressure. This increase resulted in overspending 'C' Circulator since its speed control was in manual. At 0008:06, received Loop I shutdown signal by the PPS on indication of high activity in the hot reheat header. Both 'A' and 'B' Circulators were losing speed, therefore, at 0008:27 the . R0 inserted a manual Scram. At approximately 0030 hours on 10/3/87, the Shift Supervisor ; declared an Alert and initiated RERP according to EP-1 due to the fire and subsequent damage to equipment. At 0032 hours, Loop I was recovered with 'B' Circulator providing primary coolant flow. Loop II was secured shortly thereafter. At 0817 hours the Alert classification was dropped and the plant ) entered the recovery phase. J J l l
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q 3.0; ROOT 'CAUSE OF HYDRAULIC OIL FIRE DETERMINATION )
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3.1' Hydraulic' System Description d
,,. The hydraulic
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' powe r' system: supplies- high -pressur'e- .)
hydraulic-fluid to the actuators .of high pressure fast :! operating control and' block valves;'in the secondary 'j coolant' system. There are two identical : hydraulic- power 1 5 ' systems, one for each secondary coolant loop. l -Each hydraulic power system supplies dependable hydraulic-
' fluid.at a minimum pressure 'of 2,500 psi. Sufficient i redundant storage capacity ' is availableL to -meet the d maximum simultaneous valve actuator demand, and redundant !
pumps achieve a.three minute l system recovery from maximum
-load' demand.. Four , separate supply headers- supply.the actuators of valves which are grouped for plant safety-
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reasons.
, Hydraulic; fluid returning from~the actuators flows'into q
, .the backup storage tank. prior. to returning to the.. 2 .1 reservoir, of the high pressure pumps. As the hydraulic ;
fluid flows to the reservoir, excess heat ' absorbed' from ! c the: secondary coolant. system valve actuators is removed by -- a.. heat exchanger; ,
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i . During : loss of the' main and/or the standby-pumps or lines 1
- .upsteam of the accumulators, the stored fluid is !
. sufficient .for safe shutdown'of that' loop. 'The emergency. I thiro pump provides . backup for the, " main pump" or .the j
" stand' by pump" during periods of maintenance or in case of '!
pump failure. In this case.the emergency pump is run as a
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L l main pump and .the remaining pump lis .on standby with its auto-start' feature. In addition, the third pump provides ext'ra flow capacity'in ' case of increasing system internal-leakage.
. Isolation valves for maintenance purposes are located at !
the . hydraulic power units on level one for. each of the four separate supply' headers for each loop and also at the ! individual valves.
- Fast acting hydraulic valves are required for mitigating i the consequences of moisture ingress into the PCRV, '
activity releases, and for limiting the harsh environment j following a High Energy Line Break. Environmental Qualification (EQ) parameters are partially based on these . operating' times. (
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- .3.2 'HV-2292, Inspection Results .
l; !,y , i lAs' discussed;'in? Section-- 2.0, Chrenulogy of Event'and
. Transient, the E0 dispatched;to ascertain the cause of;the
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l ': J - r L . low hydraulic.. pressure: alarm stated that. he .saw oil , flowing into the catch basin on Level 5 of the turbine '.
~ building. _ He then proceeded to.the areaof HV-2292,~ Loop !
p II main steam bypass valve, on Level 6 of' the .. turbine
< building,. because he'~ knew that .HV-2292 had been ,a L: 4 historical source of--hydraulic . oil leakage. When he; !
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? discovered the' fire, he stated that he was on the opposite !
side.of.the hot reheat safety valves:from HV-2292 and.that 011' was. " flowing" intothe fire. However,'he could'not, y Ldetect.its source. 1 j
- v. 3.2.1. Oil' Filter Canister-l i
j. Since the , hydraulic. oil filter canister had ruptured, PSC conducted comprehensive metallurgical evaluations' to determine if the filter canister was the fuel. source and initiator of the fire. -This investigation was also directed by the following: 4
'the hot reheat safeties' were' engulfed inL the-flames,. the canister was: closest to these valves, and ' the' discovery of pipe wrench marks' on the .!
cani, ster. indicating that perhaps -improper maintenance practices had compromised the canister-J integrity .(although 'no failures had been reported at; Fort St. Vrain). However, the metallurgical
. examinations determined that the filter canister could not be the primary source of the ' fire (See Appendix A).
'3.2.2 Flange /O-Ring-The:' flange and o-ring. external to the HV-2292
-lagging was investigated to determine if 'it was the source of the fuel and initiator of the fire, i Initial inspection' by.PSC found no evfdence of o-ring extrusion. R. Beaufort of-Paul.Munroe, Inc.,
PSC's Hydraulic System Consultant, confirmed that extrusion would be visible, even in the crystallized state that the o-ring was in af ter the fire, and must be present to allow leakage at this point. 'Therefore, the flange /o-ring ' configuration was eliminated as the initiating fuel source, i
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Page 7'of 26 n, , , iih * , e ' a a: 1 3.2.3 Thermal Relief Valve p
- When PSC disassembled HV-2292, .the thermal relief pf -
valve designed to compensate .for hydraulic oil L" thermal expansion was found to .be degraded to the
' point'that' it .could not reseat. Upon further.
investigation it was discovered that 'a .035" ,l .i j valve flow was
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orifice designed missing, to reduce relief Calculations. were' ~ performed- that
' indicated flow through the relief _ valve with'~the j
. orificein place was restricted to approximately-L 1 gpm at.3000 psig. . Flow through-the relief ' valve-l without the orifice 'in place was calculated to;be approximately 17 gpm at 3000 psig.
. o This discovery revealed the answer to a previously 1 non-understood phenomenon, Historically, HV-2292 l l has been the source of hydraulic oil leakage whenever the valve was stroked, as shown in the maintenance trending program. This ' leakage was
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first contributed to faulty. design of the relief valve and a new design was incorporated, alo 3 with 1 spray confinement and drain funnels for the . expelled oil. The system normally operates at I approximately 3000 psig and the relief is set at Lg 3300 psig, .w ith reset at 2900-psig. Controlled -! testing' conducted.on the " sister" valve, HV-2293, ' indicated- a- closing pressure wave peaking at ! approximately 3500 psig. This test shows that the j l relief valve would momentarily actuate when the hydraulic valve was actuated until .the pressure subsided. , The missing orifice accounts for the abnormal oil e expulsion during valve stroking of HV-2292. .; y 3.3' Ignition Source e i ,i 3.3.1 Hydraulic _011 Flammability Analysis ; i Gulf Harmony 011 #68 is the hydraulic fluid used in the Fort St. Vrain hydraulic system. This oil has ' an ignition point of 825 F when presented to a heat source in spray or. mist form. (Reference 1). However, when presented to a heat source in a laminar dispersion, the ignition point is 515 F. (Reference 2). a
w - -- 7 Page 8 of!26 d a, . 3.3.2- Stea'm Temperature / Valve Stroke Correlation ]" N_ !< Main steam bypass valve'HV-2292 closes when steam temperature reaches 760*F when the nand switch is
'placed in the auto' mode and at 800*F when in manual mode. Since HV-2292' was in auto mode when 'it .,
- stroked to' the closed position at.2350 hours,'as 1 the turbine was being prepared. to be placed on ;
'line, the steam . temperature- was. approximately {
-760 F. The. main steam bypass piping and HV-2292 .1 would. 'be heated to approximately tne :same q
. .tempe ra tu re .
3.4- Root Cause Conclusion The closing pressure wave .i s associated with the' {" termination of HV-2292 valve motion and is- sufficient- to. 7 lift the' thermal relief valve. The relief valve was unable.to reseat since the header pressure,.as seen by the
- ' relief . valve, 'was not .being -reduced by the upstream orifice. - The oil confinement system was unable to contain
.the flow volume' and velocity, which could have been as high as 17.gpm at 3000 psig without the orifice in place.
'Since operators ha've. historically experienced leakage when E
this v'alve is stroked, it is possible that this sequence oft events has occurred in the past. However, on October._2,1987, it is concluded that the leakage not ; contained by 'the drain funnel system contacted the hot surfaces and was sufficient to ignite. The preceding statement is supported.by the metallurgical analyses conducted on the hydraulic oil filter canisters. These ; evaluations concluded that the canister failure is secondary since the canister required 7000 psig at 600tF for' 1/2 hour or 2073 psig at 700 F for 1/2 hour to- ~ rupture, and that the non-uniform hardness shows evidence
. ; .: of an applied heat source direction orientation.
3: Additionally, valve closure pressure is not sufficient to f
- result in room temperature over pressurization failure.
The external flange /o-ring configuration is also not a considered to' be an initiator of the event since it did . not show evidence of o-ring extrusion. ; I
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Page 9 of 26'
. (; 4.0 FIRE MODEL DETERMINATION The fire model was developed by the PSC Fire Protection Engineer, a Fire Reconstructionist from Fay Engineering, and Sargent .& Lundy Fire Protection Engineering. The fire area was maintained intact until the forensic investigation was-completed. Physical inspection was performed to determine fire ,
zones, temperatures and durations based on established melting,
, burning, or softening temperatures associated with the variety i of materials found in the area and exposed to the fire !
environment. This inspection formed the initial fire curves. These curves were then revised based upon oil fire test data from tests done in Finland. Calculations. based on post-fire hydraulic oil inventory and fire duration indicated that approximately one-fifth of the expelled oil actually burned. This is consistent with plant personnel statements about a large .; pool of unburned hydraulic fluid on the floor below the fire i areas. Although a literature review was performed by i Sargent & Lundy to determine if mathematical fire modeling l techniques could be utilized to predict a temperature profile of j the fire,-it'was found that there are no existing mathematical fire modeling techniques for 'a " running liquid fire" such as ; occurred at Fort St. Vrain. l The results of these investigations formed the basis for the , development of detailed fire maps (Appendix B), Preliminary conclusions are cont ai ned in the Sargent & Lundy report (Reference 3) and the Fay Engineering report (Reference.4). , i
Page 10 of 26 !
.- 5.0 DAMAGE ASSESSMENT PSC has methodically identified all tagged items in the fire ,
zone. These include instruments, hydraulic operators, snubbers, .I hangers, manual . valves, safety valves, electrically operated i valves, pneumatically operated valves, fire detectors, cable i trays, . conduit,- cable, and structural materials. Environmentally- qualified equipment was also carefully scrutinized. The initial fire zones that were determined were used as a conservative basi s for evaluations. Visual inspections were performed to identify damage. The fire zones and associated evaluations were revised when sufficient forensic results warranted. Repairs and testing were performed on items ! that were not easily replaceable. However, all non-repaired equipment will be tested through Post-Maintenance Testing (PMT) or Cold Check-Out/ Functional Testing.(CCT/FT). This will include equipment outside the identified fire zone due to associated electrical circuits passing through the fire zone. Equipment is also being investigated for internal heat sensitive components and replacement will be made as necessary. Thermal Lag Analysis aging impact is being performed for EQ (MEL) equipment to define exposure temperatures. Arrhenius q calculations were then performed, assuming peak calculated j temperatures for the fire duration. Materials reviewed were: Buna-N, Polyurethane Varnish, Polyvinyl Chloride, Phenolic', l Cross-Linked Polyolefin, Polyester Amide, Neoprene, Teflon, Polyethylene, Viton, Kapton, Tefzel, Metal Film Resistors, Polythermaleze, Epoxy Glass, Epone, Polyvinylidene Fluoride, Hysol, Nylon 6/6, Glass Filled Melamine, Silicon' Rubber, and Diallyl Phthalate. The qualified life as specified in the EQ binders was then reduced by this calculated time exposure at 120 F. Materials determined to be in need of replacement before ] ' the 1989 refueling outage were identified to construction for immediate removal and replacement. Metallurgical evaluations were conducted on conduit and copper )' tubing. The samples selected were the most obviously affected i examples found in the fire zone. Hardness and microstructural examinations were performed and showed no appreciable evidence ) of damage. It was noted that the zinc coating was melting, ! indicating an exposure temperature of 780 F. Linear indications i of approximately 2 mil in depth were noted in both the zinc and f base material. This observed damage would have no detrimental
< effect on the structural capacity of the conduit.
Microstructural and microhardness examinations were performed on a representative sample of copper tubing. The results indicated no damage as a result of the fire. 9-l
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' Piping, . valves and.st'ructural-steel which were not, replaced andL l Lwere ~ in ; temperatures. zones; that scould resulted: in-
[" "" have-
;> 9f '" metallurgical-chara:teristic:Lchanges were; examined for hardness,.
.,gsubsurface cracking':andJ microstructure; phase' transformation,
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HNo; damage' was, .found, HTherefore, the safety function of these j tcomponentsfhas been verified. ' l Concrete-was'ey'aluated both visually and with the Sch'midt: Hammer: 1 methodology. Minor surface cracks' and.Lminor surface. dusting-
- were observed .t.
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.Schmidt Hammer-(qualitative compression strength)' testing =showed , "!
.no concrete spalling when struck by. .al : small . hammer and 'the '!
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concrete emitted -a distinctive. ringing . sound. 'Compres'stve strength was.founditolbe'in excess-of 3500 psi, The concrete.
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.c was concluded to be only superficially damaged with no. reduction la :in: capability. J L 3 t
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Pagel12 of 26 : I ~J 1 { . , , Y
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06.0'LDETERMINAT10NJ0F ROOT CAUSE FOR CONTROL ROOM SM0KE-INGRESS.
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. 6.1 ' System' Description The control room HVAC system is
> System' Design Intent' - -a designed to provide properly controlled ventilation air to
- the.jcontrol'~ room and' auxiliary equipment room under'all g . plant' operating ~ conditions.
l
.. Normal System 0peration'- Normal operation of this system !
# is-divided into two modes - the refrigeration moce and the 4
' economy mode ~. (See Figur'e 1). The system operates in the
' economy' mode-when Outside ambient' temperature. is at 'or j f below 53 F. .In this mode, the free outside air has enough j V , ' cooling capacity to satisfy all cooling requirements for i
, a. the: control room. air handling unit. The system switches ]
c to the~ refrigeration mode when the outside air can no 1 i M '
, longer satisfy all.the necessary cooling requirements, m
Control room supply fan C-7504 supplies ventilation air to
# 't. the controlLroom', operator's training room, and auxiliary -i 9 equipment- room via separate ducts to each of these rooms. j l
I The Control room return fan (C-7505): draws return air from the system and exhausts.it to the control room return air
. plenum. . l Depending on ' pressure and temperature o requirements, this. return air is exhausted to atmosphere and/or recirculated to the air handling unit.
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i The toilet exhaust fan (C-7507) continually exhausts to .i the: outdoors anytime the control room return fan is' on, 'jl Make-up ' air ,to~ the control room air handling unit is' normally' supplied,from outside air through DV-75299/DV- ) 75300. The . access bay , vent fan (C-7524) draws from ] outside air and/or control room return air. .j Control room pressure is maintained slightly positive with ( respect to the turbine building to ensure that any leakage ! is outward. This pressure is maintained during various modes of operation in the following manner: a
- 1) Refri.geration Mode: Pressure is maintained by throttling the outside and return air dampers {
DV-75299 and OV-75300.
- 2) Economy Mode: Pressure is maintained by throttling l the return air through either of two dampers -
DV-75303 if the access bay f an (C-7524) is on or DV-75363 if this fan is off, l l
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3)' , . Highf Radiation. ' Mode:' Pressure is maintained by d throttling the, control ~ room emergency fan- inlet I L : damper DV-75296i l
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'1 Note:- . There.' .is no pressure control during the- l purge mode'other than that provided by' supply. and. l exhaust fan capacity differences, j
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' Abnormal System Operation 'p .
In .the event'of high radiation as detected by'any one of- 'l the four. stack monitors (see Figure.?2), the following j actions occur: .j D. n ; / y. . 1) Outsice' air damper-(OV-75298) closes.
- 2) . Control room HVAC swaps to refrigeration mode.
Chilled water flow to the service building HVAC is
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isolated (FCV-7543 closes), a 4)- Control room emergency fan (C-7506) auto starts. )
.The control room HVAC .in this high radiation mode (see -
Figure 3) now operates as during the normal refrigeration mode, except the make-up'. air is drawn from the turbine !
- building,and passes through the emergency fan and filter
'(F-7502) before entering the air handling unit. Control room pressure will now b2- maintained by throttling l DV-75296.
4 Anytime smoke :is detected in either the control. room or auxiliary equipment room, ventilation supply air is ; automatically directed through the control room charcoal filter (F-7504) in addition to the normal control room filter (F-7503). i y The purge mode (see Figure 4) is initiated manually by 1 'taking HS-75184 to purge. This action . reopens the ; isolation, the isolation dampers and positions the system J dampers to supply 100*4 outside air and exhaust 100'e of the f return air to outdoors.
, Differential Pressure Control - The purpose of PDT-7556 is i, , to provide the signal which maintains a positive prs.ssure l' differential between the control room and the turbine building.
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-il p, !6;2' Operator' Statements w -
Operators in the control room at the time of the fire have !
., . l indicated that the concentration of smoke in - the ' control ,
room was an ' eye irritant, The breathing f air system was -i
'used; sporadically'since there were 3 masts' for 7 men.
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'However, at no time did the' operators consider _ev'acuating the. control room. .0perators: noticed smoke entering'around
'l the doors, ,
There .was one entry.into'the auxiliary electric room at
'0047' hours on October 3, 1987. .At this time, the operator noticed no smoke in this area. 1 6.3 -Conclusions j The. pressure . differential control sensing line, which is 'l
. currently located in the auxiliary-electric room, does not i provide adequate differential pressure control between.the turbine-building. j f
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Page 19 of 26 it 7.0 ROOT CAUSE FOR 'C' CIRCULATOR TRIP L The trip lof .'C' Circulator'is still under evaluation.
.At 0006:22, 'C' Circulator tripped on. fixed high soeed. Plots show a substantial increase in cold reheat pressure at this time. Apparently, the fire affected the mainsteam bypass control valves causing one or more of'them to go open, resulting
.in an overspeed condition.
Data logger printouts did not conclusively indicate that tha overspeed trip for 'C'. Circulator at 0006:22 was an actual fixed i high speed trip. .Therefore, comprehensive tests were conducted. The high speed PPS trips for 'C' Circulator have been tested. The water turbine trips were set at 8620-8690 rpm, all within the . acceptance criteria. The steam turbine trips were set at 10710-10800 rpm, all within the acceptance ' criteria. (SSR l 87509037). The steam turbine speed indication on 'C' Circulator, SI-2106, was tested and was within the acceptance criteria. (SSR 87509069). The water turbine speed indication on 'C' Circulator, 51-2110, was tested and was within the acceptance criteria. (SSR 875090709). Therefore, it is postulated that since all of the indicating parameters for input into the PPS logic for a fixed high speed trip have been tested and proven to be capable of proper function, a steam spike caused by the loss of main steam bypass control as' a result of the fi re actually oversped 'C' Circulator. 6 0 L i
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.Page 20:of 26 n Le >
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'8'0 . FIRE DETECTION AND ANNUNCIATION '
W - 8.1 System Description The. fire detection' system is designed to auickly' notify. _,
- x. operations' personnel of potential' fires and to' . activate .
U' associated' fire suppression systems. Distinctive audible- l and-visual ~ alarms anrunciate. in Ethe control room and l locallyj when a fire.. detector. is. activated. . The sytem- 'j
' ".D : complies with the intent.of the following NFPA -Codes as l
indicated.in the Fire Protection Program Plan: i
;I 172A-(1979)- Local Protective Signaling Systems 720 (1979) . Installation, Maintenance anc Use of.
Proprietary Protective Signaling-Systems 72E (1984) Autouatic Fire Detectors ) 1 All plant areas' housing safe shutdowr -equipment' ore- 1 pretected' by automatic - fire' detection. This1 includes ~ fire detection for.the following areas: ,
. I L*' , Reactor building. H Turbine building.
Standby diasel generator rooms
,s Auxiliary boiler room -
Turbine lube oil storage' room- , LTurbine lube oil reservoir room a Control room Auxiliary electric-room. . 480 volt switchgear room Building 10
. Circulating' water' makeup pump house l
' Service water pump house
,y Technical' supporting building Power for .each detector is provided from a non-r interruptible power supply and electric l circuit
, supervision monitor's for, open circuit, closed circuit, or
~
- loss of control power conditions.
jE Exemptions have been granted. by the NRC from 10 CFR i Appendix R, Section III.G for the control room, reactor ~ l and turbine building fire detection systems, as noted in ei the Fire Protection Program Plan.
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Page 21 of 26 j l 8.2 Equipment Inoperable Prior to Fire Prior to the. fire, the following detectors were inoperable: XD-45356 (photoelectric smoke detector on Level .2 of the reactor building), XD-45359 (linear beam detector on Level 2 of the reactor building), and XD-45372 (linear beam detector on Level 5 of the reactor building). PSC was working on these and other detection system ,: problems prior lto the fire and had scheduled a meeting l with Gamewell personnel in an effort to reselve -these ; problems. It has been determined that the audible alarm was silenced due to- frequent alarms .associatea with tne detection i system. l i l l l
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1 p :h h' 9.0 LICENSINGASSESSMEM'
.?
Ty .9.1 Appendix R Determinations-The fire occurred in an area defined as a non-congested
-cable area. Appendix R submittals_that are. pending with
- the NRC analyzed the . effects- of fire on safe shutdown
. capability. It'was realized that. fire in this area could affect 'the.' hydraulic and electric systems-in both loops.
There.was a potential for .an interruption of forced. circulation. Locally actuated acc'umulators were-specifically added to. p valves FV-2205~and FV-2206,-Loop I and II feedwater flow control valves, to assure'feedwater flow after an event of L, this ~ nature. . The analysis was proven as the fire did u
. eliminate electric control of.these valves. FV-2206 was
- stroked to the open position with the local accumulator, .
allowing feedwater' flow to Loop II. ]
. Initially, -FV-2205 'was thought t'o be damaged because it )
4 ~could not be stroked full open with the accumulator (it was in 'mid position after the fire). However, a. procedural error was found that, when eliminated, allowed the valve to stroke. Therefore, both trains analyzed for ! l use in Appendix R submittals were functional. L
' Additionally, the operators 'did not have to use the Appendix R trains,-although they were both operational and could have been used if normal cooling modes could not be reestablished. ~This event proves that the Fort St. Vrain approach to defense-'in-depth was valid and, therefore, the i Appendix R analyses and submittals are correct; i 4 9.2 Appendix A Determinations -r : Appendix A fire hazards analyses evaluated this area as a q['
high hazard possibility. Fire detection was enhanced with the addition of detectors above the hydraulically-operated valves. Suppression was enhanced with the addition of two
- 1. 100' CO hose reels and the extension of CO 2 piping.
Although the Appendix A analyses are considered to have enveloped this event, further enhancements will be evaluated. i 1 j u - - - - - - - _
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Page 23.00 26 @ m.
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g., , 9:3 ! Control Room Habitability Th'eL control room HVAC. system successfully switched to the s radiation.. mode, which takes minimum makeup 'from 'the turbine. building on receipt of.a radiation' alarm from.the
# . ventilation stack monitor, in this mode,.the control' room n
HEPA and charcoal filters removed the smoke that was being. drawn-in'from the turbine b'uilding. . This Lis . proven in that' .the auxiliary electric rcom,. which is . served by the 4 same'HVAC. system, had no Halon discharge. 1 The oreathing ' air system worked as designed, proving the
. validity ~of' defense-in-depth'. Scott air paks were also available-in the control' room, had they been necessary.
~
'M ': As' ,previously- discussed,- pressure control system i
' modifications are required to maintain the control room in-a positive pressure environment.
9.4-- . Hydraulic' System Technical Specification Leakage in..the hydraulic' system was . evaluated 'for_ the
. adequacy of Technical Specification suitability. It 'was-
'concludedL.that a Technical Specification on flow leakage
..would not be practical.
., ' Leakage concerns associated with the' hydraulic system are
, adequately covered by the proposed Upgraded Technical
' Specifications and existing plant instrumentation, 9.5- Overall Hydraulic System Assessment The hydraulic system as installed at Fort St. Vrain is required for . normal operation and control, Accident scenarios require fast acting valves to mitigate the i consequences of'an EES (evaporator-economizer-superheater),
or hot reheat tube leak or. a HELB (High Energy Line Break). SLRDIS (Steam- Line Rupture Detection- and Isolation System) incorporated the current valve closure times in the development of the temperature profiles used to determine EQ environmental _ equipment qualification. Valve stroke times could be -relaxed, but not sufficiently to justify elimination of System 91. i l l o _ -. _ _ _ _ _ _ _ _ . _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ .
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&V l'0.0 ACTION ITEMS V '10.1. Prior'to Rise to Power ,1;*
*- Restore plant systgms Fix Hy-2292 hydraulics (flow valve / orifice) m :* Verify ~ orifice installations
-{c +- Procedure to ban use'of pipe wrenches on oil filter canisters
- ' Install oil bleed line for canisters
> + . Cleanup hydraulic oil system-
. Modify control room pressure tap a , '*- Verify control room HVAC. performance L J *
' Perform control room filter surveillance -
' ' Perform reactor building filter surveillt.nce
* . Initiate management directive on fire alarms Issue new procedure on: fire protection. operability -!
Determine compensatory actions associated with the fire detection systems
- Install hydraulic oil storage lockers
' Review SSR(s) for missing handwheels !
- Evaluate / replace plastic valve handles l
* - Install additional masks in the control room "
- Submit LER-10.2' Next Steps !
- Replace ' oil filter canisters
- Evaluate removal of thermal relief valve l
*- Enhance pre-fire plans l
- Evaluate fire detection system enhancements Evaluate suppression needs for hydraulic oil hazard areas Evaluate catch basin. enhancements
- Issue final fire report i
i I i I l l l l L !
Page 25 of 26 1 i
11.0 CONCLUSION
PSC has completely evaluated the fire and its associated effects and has determined that this event was thoroughly considered and l analyzed. Off normal. aspects were adequately accommodated by l
-defense-in-depth design features and capabilities.
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12.0 REFERENCES
AND APPENDIXES ) References
- 1. GA - A13887 ;
- 2. Gulf 011 Report,-March 15, 1976 !
\
- 3. Sargent & Lundy-Report !
l 4 Fay Engineering Report Appendixes A. Oil Ftiter Canister Metallurgical Report i I R. Fire Maps ; 1 f l i
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.Page 2 of 15
/7 id e 3 ABSTRACT Failuret of the HV-2292:filt'er' assembly bowl occurred during the fire-
- of October 2,:1987. Metallurgical examination revealed that :the J: /
aluminum ' alloy :6061-T6 bowl failed by ductile tensile. overload at elevated temperature as a result of the fire. .The ~ temperature at.
.failuce ,was determined .to be above 650'F. No evidence of material ^
defects or alternate cracking mechanisms'was observed'.' x The filter assembly from HV-2253.was. removed for burst testing. .This assembly (also 6061-T6)~was first pressurized to 14,400.: psi before failure .-ofx the . pressure' indicator occurred. .A new steel plug was installed..and the assembly was repressurized to 14,400 . psi,. which
., resulted in failure at the last engaged thread. Finally, .the bowl !
7 'was heat. treated at 700*F.for'30 minutes,._ to' match the mechanical e, -
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properties of'the bowl from HV-2292 at the rupture. - pressure testing. resulted in-a: burst' pressure of 5100 psi at 150'F. Therefore, even !
.in this softened conditionLtne actual bursting pressure was.1600 psi !
greater _than the. maximum operating pressure of 3500 psi'. .Also, the 3 reduction ofr area at the rupture was '37.5%, compared with 78% for the'
-bowl from HV-2292. Thesel facts. illustrate'that the rupture 'of- the HV-2292 bowl occurred at elevated temperature.
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Y , 1.0 l PURPOSE
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J r ,. } Thea purpose of this metallurgical evaluation was te perform a I failure analysis of the HV-2292 filter assembly bowl. which had failed on October 2, 1987.. j 2.0 . INTRODUCTION l J The failed ft!ter. assembly was a Pall Industrial model number l HH9021A12VPSW assembly. The material was specified by' the l manufacturer- to be aluminum alloy 6061-T6. Alloy 6061-T6 is an l alum!num-magnesium-silicon alloy, in the T6 precipitation J e age-hardened temper condition. The material was not 1 manufactured to any standard ' specification such as an ASTM - 1 standard. The nominal chemical composition of 6061-T6 is shr>wn- ; in Table 1, with the actual values also' listed. Typical 1 nechanical properties are a tensile strength of 45,000 psi, ; ,t yield strength of 40,000 psi,17% elongation, and a hardness of j
~
95 Brinell. Typical ' operating conditions were 3,000 psi, at -1 150 F, with a max 1 mum' pressure spike of 3500 psi, i 3.0 DISCUSSION ) i The failed : bowl is shown in Figure 1. Evident is the slight f lateral. bulging at the rupture (2,665" 0.0., ' compared with a nominal 2.5" 0.0.); . discoloration from the fire at the end of { the bowl; and pipe wrench gouging marks near the threaded end, I not associated with the failure. Figure 2 is a profile view of l the filter, showing the extensive radial bulging (2.854" 0.0.) l i at the rupture. Figure 3 is a diagram identifying the dimensional measurements (0.D. and thickness) taken at various l sections of the bowl, with corresponding Brinell hardness values j also listed. .Here it is seen that the wall thinning. has only i occurred near -the rupture. Chemicel analysis of the bowl j revealed that it met the' requirements of aluminum alloy 6061, as 1 shown in Table 1, l 1 Figure 4 shows a higher magnification view of the rupture, which j extends approximately 0.94" in length. A cross section through J I
-. the _ rupture was taken at A, and figure 5 illustrates the 1 extensive necking observed. The minimum thickness observed at mid-rupture was 0.072", which represents a 78% reduction in l thickness (0.32" nominal). Figure 6 is a Scanning Electron
-C Microstope ,(SEM) macrograph, showing the polished, rear section .
of Figure 5. Here again the necking is shown, and evident is j the internal crack formation, which is a classic example of i tensile overload failure. The fracture surfaces were separated, l and figure 7 shows the surface examined with the SEM. This l shcws the relatively constant reduction in thickness along the j rupture (refer to Figure 3). l 1 4 I l l
Page 4 of 15 I SEM anabsis was performed, and Figure 8 shows a typical area observed. Even at this low magnification, dimpled facets are faintly evident. At higher magnification, Figure 9 clearly Hlustrates the dimples observed. Dimpled facets are indicative of a ductile tensile overload fracture. There was no evidence of any other failure mechanism (such as fatigue or creep), and also there were no defects or pre-cracks observed. Microscopic examination was performed, and Figure 10 shows an area observed at -the threaded section. This is a typical microstructure for alloy 6061-T6, and evident are precipitates of Mg:Si (dark) and particles of an iron-rich phase (gray). Some red-like . precipitates of Mg:Si are evident, which form as a E result uf overaging. The typical hardness measured in this area was HB 73.5. This is significantly lower than the typical T6 l' hardness (35 HB), which indicates that slight overaging has l occurred. The typical aging temperature for the T6 alloy is 300-400*F, and overaging occurs with extended exposure at , temperatures even slightly lower, and with exposure at more l elevated temperatures. Adjacent to the threaded area (Section 1 of Figure 3), the i microstructure observed was indicative of more severe overaging. l Figure 1 ). . shows the typical structure observed at the rupture side of this section, where the heavy precipitation is evident. The typical hardness of this area has been reduced to HB 56.7. Examination near the rupture revealed evidence of even more extensive overaging. Figure 12 shows an area observed where even a greater density of precipitates is present. Also evident are areas of grain boundary melting, such as at A. Adjacent to ) the rupture, Figure 13 shows a general elongation of the grains, j and some tearing is evident. At higher magnification, Figure 14 shows even more grain boundary melting, with some tearing associated with these areas. Grain boundary melting of the
, Al-Mg-Si alloys has been reported to occur at a minimum temperature of approximately 840 F. No other areas of grain boundary melting *.ere observed in other sections of the bowl, only near the rupture. This indicates very localized overheating at the rupture, with general overheating (at a mucn lower temperature) along the length of the bowl (as evidenced by the microstructure and hardness values). The hardness adjacent to the rupture had been reduced t.o HB 42.7. Finally, no defects 3
near the rupture were observed. , Temperature exposure above 212 F reduces the mechanical ! properties of 6061-T6. Elevated temperature properties of 6061-T6 are listed in Table 2 (Reference 1). The temperature exposure history of the bowl is unknown. There are two possible ! scenarios; 1) prior elevated temperature exposure prior to the ; fire, 2) elevated temperature exposure as a result of the fire.
Pege 5 of 15 l t The hardness at the rupture is 43 HB, which indicates an
. approximate ultimate tensile strength of 23,000 psi. The bursting pressure utilizing the expression in Appendix I for a UTS of 23,000 psi would be 6700 psi. The maximum operating pressure of the bowl was reported by Engineering to be 3500 psi. 1
-Therefore the normal operating pressure would not have ruptured I L the bowl from HV-2292 without exposure to elevated temperature under operating pressure.
y The reduction of area of the rupture was approximately 78% which indicates a failure' at elevated temperature. The minimum exposure time at temperature listed in Table 1, is 30 minutes. The duration of the fire was 15 minutes. The data in Table 1 would indicate that the temperature at the time of failure was j above 650*F. The bursting pressure for a 1/2 hour exposure at ! 600 F is 7,000 psi and 2,073 psi for a 1/2 hour exposure at 700*F, , The filter assembly from HV-2253 was removed for testing and is shown in Figure 15. This assembly is identical to the one that t - roptured on HV-2292. Pipe wrench gouge marks from removal dtring maintenance were observed as shown in Figure 15. These types of indentations were also observed on the failed bowl from HV-2292. A chemical analysis was performed on the filter bowl from HV-2253 and the results are listed in Table 1. The chemical analysis indicated the bowl is a 6061 aluminum alloy material. Hardness testing was performed and found to be a 125 HB indicating the bowl is in a T6 tempered condition. In order to determine the bursting pressure of a filter assembly, pressure testing was performed. The internal filter was removed and the assembly was filled with water, capped and heated to 150*F. Pressure was applied with a hydrostatic hand pump and monitored with a 30,000 psi pressure gauge. The filter assembly attained a maximum pressure of 14,400 psi prior to the shearing of the t 3/4"-16 threaded pressure indicator at the threads, as shown in
. Figure 16.
The outside diameter of the filter bowl increased from 2.498" to 2.510" with no measurable change in the original wall thickness of .325". A steel plug was screwed into the filter assembly head and the filter assembly was again pressurized to 14,400 psi prior to failure. The failure occurred at the last engaged thread as shown in Figures 17-19. The outside diameter and the wall thickness of the filter bowl did not mecsurably change as a result of the second test. 4 f b --__.__--_.n_
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.Page 6.of 15' ;
i l I The ' bowl -from HV-2253 was then heated at:700'F.for 30 minutes, to.obtain a hardness in the range of HB 43. . Testing could then ) i be . performed to determine the bursting pressure of a bowl with
-mechanical properties equivalent to'those of the failed -HV-2292 ,
bowi..(with.a hardness. of HB' 43 at the' rupture). Hardness. I testing af ter the heat. treatment revealed a' harcness.of ' HB 39;
.Since from previous testing, .the threads had failed, a' cap was'- i welded on the. assembly for. pressure .. testing.' The bowl was ':
- pressurized to 5100 psi at 150*F when it burst. This value is j 1600fpsi lower than'the calculated bursting pressure of 6700-
. psi. This is most likely due to the lower actual. hardness level c' 39 K8,' compared with the value used'in calculation- (43 HB),
and inherent inaccuracies in the calculation. This test does illustrate, however, that the bowl from liv-2292 could not have failed due to overpressurization without expesure to elevated 1 temperature, since.the maximum operating pressure was'.3500 psi. ' Also, the. reduction --of area at the rupture was 37.5% compared with.the 78% reduction. seen in the bowl from HV-2292. This further indicates'. that' the rupture: of the bowl from HV-2292 occurred at elevated temperature. LTherefore, based on the fractographic (i.e., SEM) and metallographic ' examinations, hardness testing, mechanical
- property data, and pressure testing of the HV-2253 filter 1 assembly, it was determined that failure of tr.e HV-2292 bowl occurred. by ' ductile tensile overload at elevated temperature (above 650 F). 'l 4.0 ' CONCLUSIONS
- The filter assembly bowl from HV-22: which had ruptured is a 6061 aluminum alloy material a , specified by the manufacturer.
- No evidence of manufacturing' defects or'other cracking mechanisms such as fatigue were observed.
i
- The filter assembly bowl from HV-2292 failed due to I elevated temperature exposure f rom the fire (above 650 F), j lowering the mechanical properties, resulting in a ductile i tensile overload.
- The filter assembly from HV-2253 was removed and the bowl was found to be a 6061-T6 material as specified by the ;
manufacturer.
- The filter assembly from HV-2253 was pressurized to 14,400 psi before the pressure indicator failed.
- Installing a new steel plug and repressurizing to 14,400 psi resulted in failure at the last engaged thread.
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i Page 7 of 15 '
-l l <
+- The filter assembly from HV-2253 was heat treated at 700 F l for 30 minutes, to match the mechanical properties of the 1 4
bowl from'HV-2292.
- Pressure- testing resulted in a' burst pressure of 5100 psi j at 150 F. .The maximum operating. pressure is~ 3500 psi, The ' reduction of area at the rupture was 37.5%, compared 1 with 78% for 'the bowl from HV-2292. These facts illustrate that the rupture of the HV-2232 bowl occurred ,
at elevatt.d temperature. J
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1 7ABLE 1 i CHEMICAL ANALYSIS 4 STANDARD 6061-T6 FAILED HV-2292 BOWL HV-2253 B0WL ELEMENT (WT. %) (WT. %) _(WT. %) , Magnesium 0.80 - 1.20 0.87 1.04 j Silicon 0.40 - 0.80 0.40 0.62 ) Iron 0.70 (Max.) 0.19 0.13 l Copper 0.15 - 0.40 0.20 0.21 l l Manganese 0.15 (Max.) 0.01 < 0.01 !
., Chromium- 0.04 - 0.35 '0.14 0.12 l 1 Zinc 0.25 (Max.) 0.06 < 0.01 l Titanium 0.15 (Max.) 0.02 0.01 i Zirconium 0.05 (Max.) 0.003 < 0.01 l Aluminum Remainder 98.11 97.87 l
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Page 9 of. 15 I 1 TABLE 2 l Prior Exposure (1)l Test lElasticlYield (2)l Tensile 1 l l l Temp. l Time [ Temp.lModulesl Strength l Strength lElong.l R. A,1 l *F 1 hr. -l 'F l10' psi l1000 psi 11000 psi 1 % (3)l % l t l l 1 l l l l 1 l l ', l l l Room l l 39.5 l 43.0 l 16.5 l 45 l l I l l l l 1 l l l l
- j. l l Room l l 39.3 1 42.4 l 16.5 1 45 l l
' l- 1 l 1 l l I l-- I l l l Room l l 39.8 I 45.2 l 12.0 l 32 l l l I L__ -- ! ! I I l 212 l 1/2 l Room l l 40.0 l 43.1 l 18.0 ll _.4 7 l )
l l l 1 I . I I I -1 i 1 212 l 360 l Room l l 40~6 l 43.5 l 17.0 l 45 l j
'l i l l l~ 1 l- 1 I l l 212 l 2400 iRoom l l 41.5 1 44.1 1 17.0 1 45 I l 1 1 I I l -- l l l l I l 212 1 10000 l Room l l 41.5 l 43.8 l 17.0 l 45 l I
l I l l I I ___ l - - I l {
] 300 l 1/2 l Room l l 39.6 l 42.6 l 17.5 1 47 -l j l 1 I I I I I I I !
l 300 l 16 l Room l l 40.5 1 43.3 l 17.0 1 45 1 ; 1 I I l l 1 I I I
+
-l 300 1 96 l Room l l 41.3 l 43.3 l 16.0 1 46 l '
l l 1 I I I l. I i I 300 l 480 l Room l l 40.9 l 43.2 l 16.5 I 49 l l l l l l 1 I I I i I 300 1 1920 l Room l l 39.8 I 42.5 117.01 49 l ] I I I I I - l l I i 1 l 300 l 5000 IRoom l l 37.3 l 40.1 115.51 46 l l 1 I i l 1 l I l l 300 l 10000 l Room-l l 36.6 1 39.4 l 16.0 l 46 l { l l l l I l l I l 400 l 1/2~ l1 Room i j 39.4 l' 42.0 l l 17.0 1 47 I I l l l l 1 - 1 I l ! l
- c. l 400 l 6 ) Room l l 38.7 l 40.9 l 15.5 l 47 l l l l l l l 1 -- I I __ l l 400 l 30 [ Room l l 35.3 l 38.3 1 16.5 1 48 l l I I I I I I I I l' l 400 1 96 1 Room l l 33.4 1 36.9 l 16.0 l 48 1 e I i l l l l 1 I I j i 400 l 480 l Room l l 30.4 l 35.3 1 16.0 l 51 I )
l I _ _ . I I I .1 I I I i l 400 l 2400 l Room l l 24.1 1 31.6 1 17.0 l 55 1 I I I I I I I I - - _ -I 1 l 400 l 7392 l Room l l 23.7 l 31.3 1 17.0 l 56 l ) 1 I I I i l 1 I I 19.2 28.3 l 17.5 l l 400 l 10000 l Room l l l 52 I j l 1 I l l 1 I I I j I l
- - - - 1
Page 10 of 15
.. 1 TABLE 2 (con't) l Prior Exposure (1)l test 161asticlYield (2)l Tensile I l l !
q l Temp. l Time l Temp.lModuleslStrength l Strength lElong.l R. A l l1 l 'F l hr. I F 110' psil1000 psi l1000 psi i % (3){ % i I I l l l l l l l l
.l 500 l 1/2 l Room l l 35.3 l 38.4 l 17.0 l 48 l l l l I I l I i 1 l l __600 l l 16 l Room l l 16.9 l 26.6 l 18.5 I 56 l l 1 l 1 I l 1 l i I j I 500 1 72 1 Room I I 12.4 l 23.2 l 20.5 l 60 I i . I - - . I l l l l' I l I (
l 500 l 360 1 Room l l 13.6 1 24.1 1 19.5 I 57 l {' l I I I l l-- 1 I l l 500 l 960 IRoom l l 9.0 l 20.2 1 25.5 I 60 l j l ! I l l l I i l ] l -500 l 3600 1 Room l l 6.9 l 18.5 1 31.0 1 60 l j l I l I l l I l l l l 600 l 1/2 iRoom I i 19.1 l 28.1 l 18.0 l 56 l l l l l l I I I I i 1 1 600 l 4 l Room 1 l 14.2 l 24.6 l 19.5 l 58 l
- l. I 1. I I I l l 1
]
l 600 l 30 iRoom l l 10.3 1 21.4 l 23.5 l 59 l l l I I I I I i l ! l 1 600 l 96 l Room I l 7.6 l 19.5 1 29.0 l 58 l ; I I I l l l 1 l l I l 600 l 480 l Room l l 6.2 l 17.9 l 34.5 l 62 l '{ l__ l I l l l l l - _ - - 1 J l 600 l 1440 l Room l l 6.1 1 17.6 l 34.5 l 61 I I I I I l l 1 l l .
,- l 600 1 5000 iRoom i I 5.9 1 17.3 l 44.0 1 63 l l ' '. ' I l l l I I l l l l l 600 l 16800 JRoom 1 I 5.9 l 17.0 l 34.0 1 61 l l l I I I I I I l l !
l l 700 l 1/2 l Room l l 13.3 l 24.3 t 20.0 l 32 l I I i l l I I I I l700 l 4 l Room l l 7.9 l 19.9 l 27.5 I 57 l 1 I ~ ~I I I l 1 I I I ! l 7(iO l 16 1 Room i 1 6.4 l 18.6 i 33.0 l 61 l l l 1 I I I i i l ll ~ 700 l 960 lkoom I I 6.3 l 17.7 l 34.0 l 62 I l I I 1 J l l -l l l l 700 1 10000 l Room l l 6.3 l 17.4 l 33.5 l 61 I l i I l l__ l I ! l l l l [ 800 1 1/2 l Room I i 7.3 l 20.4 l 30.5 l 59 l l I i 1 I I I I ! , I 900 l 1/2 l Room l l 8.2 l 21.7 1 30.0 l 57 i i l l I _I l l I i ! l 1000 l 1/2 l Room l l 9.1 l 23.5 126.01 53 1
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L Page 11 of 15 ' q c j, TABLE 2 (can't) l l I)rior Exposure (1)lTest IElasticlYield (2)I-Tensile ( l l I Temp .' l . Time l Temp.1ModuleslStrength l$trength lElong.1 R. A.! l *F l hr. I 'F 110' psil1000 psi 11000 psi i % (3)I % I i~ l 1 l (_ l l -I I 1 i l 212 l 1/2 { 212 i l 38.3 l 40.6 l 18 5 I 50 l l- -l _l l 1 I I I I l 212 1 360 1 212 l l- 38.8 1 41.0 l 17.5 1 46 l 212 F0'0 212 1 40.2 41.7 17.0 48 i I l __ _ _ .- I- I l __ l- 1 I l l 212 l 10000 l 212 l l 40.2 l 41.4 l 16.0 1 46 l l 1 1 -- l _I i I I I 300 1 1/2 l 300 l l 36.2 1 36.9 l 20.0 l 52 I ' l l _l -I I l l l l 300 l 16 I. l300 l l 36.7 l 37.5 l 19.0 l 51 l l 300 96 300 T7T2 37.9 l 17.5 9'~ l I l i 1 -.l_ l l_ l l I 300 1 480 l 300 l l 3 7.5 l 38.1 1 17.5 l 53 l l l l. I I l. - 1 I .I l 300 i 1920 l 300 l I 36.6 l 37.2 l 17.5 I 51 l l 1 1 I I I I I i l 300 1 5000 l 300 l [ 34.2 1 35.2 l 18.0 1 50 l l l l l l 1 l l l I 300 1 10000 l 300 ( l 33.5 1 34.2 1 19.0 l 52 l l l i I I i l l _. I 1 400 l 1/2 1 400 l l 32.9 l 33.0 l 19.0 l 56 l 1 I I I I I I I l l 400 l 6 l 400 l l 31.9 l 32.1 l 18.5 l 56 l l 400 30 400 29.5 l 30.2 20.0 56 l 400 l 96 00 l l 28.4 29.1 20.0 59 l l l 1 l l l I l. l l 400 1 480 1 400 l l 25.9 l 27.3 l 20.5 l 60 I I l l l l 1 i l l 400 l 2400 l 400 l l 20.4 l 22.6 l 23.5 ll_ 65 l 1 I I I I I I I I l l 400 1 7200 1 400 l l 16.5 l 19.7 1 26.0 1 65 1 ^ 1 1 _. 1 I I I I I l_ l l 400 1 10000 1 400 I i 15.3 l 18.1 1 28.0 1 71 l l l l I I i i l i I 500 l 1/2 1 500 I l 22.7 1 23.3 1 18.5 I 63 l l l _1 I I -_ _1 l l l 1 l 500 l 16 I 500 l I -14.4 l 16.1 1 27.0 I 74 l 'j i l l___l l l 13.4 1 I I l 500 1 72 1 500 l l 11.5 l 1 31.5 l 76 l l l l l l l l 1 l l 500 1 360 1 500 I l 8. 6 l 10.9 l 46.5 1 80 l l l l l 1 -_I l l l l i _ _ _ . _ ._ _ _ - _ _ _ ]
7 y ' Page 12 of 15 , TABLE 2 (con't) 1 IPrior Exposure (1)lTest IElasticlYield (2)l Tensile j i ~l l Temp. l Time ITemp.lModuleslStrength IStrength lElong.l R. A.] l 'F l br. 1 *F .110' pstl1000 psi 11000 psi i % (3)) % i
- l. I I l _ _ _ .. __ l l 1 l_
i 500 _Il 960 1 500 l l 9.2 l 11.6 l 42.0 1 79 l 8 l _. 1 I I I I i - l_ -- _ l - 1 503 l 3600 l 500 1 1 7.4 1 10 0 l 50.5 1 82 1 : 1 -- l 1 1 I I l __.___. l _ _ _ i l 600 1 1/2 l 600 l l 10.9 l 12.0 1 23.0 1 74 i I i 1 l_ l i I l_ l i l 60.0 l 4 1 600 l l 9.0 l 10.3 I 34.0 l 82 l l _ l l I I I _1 1 1 1_ 600 1 30 1 600 l l 7.1 1 8.7 l 48.0 1 86 l 1 l_ l I i i l l I l 600 l 96 l 600 1 1 5.2 l 6.7 1 64.0 1 89 l 1 L_ l__ -- - l _ l._ - 1 I I I 1 600 1 480 l 600 1 1 4.0 1 5.1 1 P2.0 l 92 I I I l_.._I_ l I l _- - 1 1 l 600 1 1440 l 600 1 1 4.2 l 5.3 1 63.5 l 91 l l _. I __ L I I I I I 1 l 600 j 5000 l 600 l l 3.8 l 5.0 l 99.0 1 93 1 4 I I I I I I I I I
!' 1 600 1 16800 1 600 l l 3.7 l 4.8 l 62.5 l 93 l >
I I I I I I I -l. I l 1 700 l 1/2 1 700 l 1 6.1 l 7.1 1 27.5 l 85 1 ! I i l I i i l i I < J 700 l 4 1 700 l l 3.7 l 4.6 l 68.5 l 93 l
- l. I i .I I I I i __-1 l 700 1 16 1 700 ( l 3.0 1 3.7 l 98.5 l 95 I I l l -l l 1 -I 1 Il ~T60 1 96 'l 700 l l 3.0 1 3.8 l 96.0 l 94 l 1 I 1 -I _I I I l _ -- 1 l 700 1 960 l 700 l l 2.9 1 3.7 l 91.5 l 95 l 1 I I _ I L. I 1 l l l 700 l 9552 l 700 l l 2.7 1 3.3 l 81.0 l 95 l l I' I I l 2.0 1 I I -l I 800 l 1/2 l 800 l i 1 2.5 1105.5 l 97 l 1 I i l i i 1 1 I .
98 l l 900 l 1/2 l 903 l 1 1.5 1 2.0 l113.5 l I I I I~ I I I I l 1000 l- 1/2 11000 l l 1. ~3 'lI 1.6 1 96.0 l 91 l l 1 1 I I i l I i (1) Conditions of exposure, if any, between heat treatment and testing. (2) 0.2% offset yield strength unless otherwise specified. I (3) Elongation in 2 inches unless otherwise specified. 1 l l l
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Page 14.of'15 P = 2VT a'- b a+b P = Bursting Pressure (PSI) UT = Ultimated Tensile Strength a = Outside Radius b = Inside Radius t Roark and Young: Formulas for Stress and Strain, McGraw-Hill Book Company, Fifth Edition, 1975, .I I I 1 i 't i { l
Page 15 of 15
5.0 REFERENCES
- 1. Howard R., Voor1 tees, Freeman J. W. " Report on the Elevated-Temperature Properties of Aluminum and Magnesium Alloys."
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- I Figure 2. Macrograph showing a profile view of the bowl, where eviden:. 's the significant bulging at the rupture. Magnification:
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1 1 s Figure 5, A cross section through the rupture ( A of figure 4), illustrating the extensive necking. flagni fication : 3X. l 1 1
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