ML20147E430
| ML20147E430 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 11/12/1996 |
| From: | Mcelhaney K OAK RIDGE NATIONAL LABORATORY |
| To: | NRC |
| Shared Package | |
| ML20147E427 | List: |
| References | |
| CON-FIN-W-6324, FOIA-97-177 NUDOCS 9703030072 | |
| Download: ML20147E430 (13) | |
Text
_
s Evaluation of Candidate ISSC Check Valves for Risk Based IST Extension at Palo Verde Units 1,2,3 K.L. McE1haney Oak Ridge National Laboratory Oak Ridge, Tennessee November 12,1996 NRC Job Code W6324
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___.__-.m Evaluation of Candidate LSSC Check Valyes for Risk Based IST E*nsion at Palo
_e Verde Units 1,2,3
===.
Background===
Palo Verde Nuclear Generating Station has recently submitted to the NRC a request for relief from the laservice Test OST) intervals currently required by the ASME Code for certain check valves based on a probabilistic analysis of the valves' importance to safety, la theory, this analysts methodology results in the ranking of components into two basic categories, those of high safety signi6cance and those with low safety si-i8-The goal is to ensure that the components more important to plant safety are to be tested in a manner that provides a high level of assurance of their operability. Another goal of the Risk Based approach (RBIST) is to show that IST intervals may be extended beyond the current requirements without resulting in significantly increased safety risks. One consideration in this type of analyas is supposed to be component performance history, both from the specific plant as well as from an industry penpeetive.
Palo Verde has requested IST extension from their cunent Code requirements (usually quarterly) to an interval of 6 years on approximately 228 (assunung 76 valve application groups / unit x 3 units) " low risk significant" check valves. In an effort to provide information needed to evaluate potential r=adidate check valves at Palo Verde for extended IST intervals, Oak Ridge National Laboratory (ORNL) has done a brief review of the available performance data for the valves in question. The following is a enmmary report on that analysis.
Analysis Results An analysis was done on avadable component perform =are data using both the charactertzed data from the ORNL check valve performance database and raw NPRDS data. The ORNL datahaw is==p=M of over 2000 check valve failure records derived from NPRDS from 1984-1992, and manually reviewed, filtered to remove non failures, non-check valves, and external leakage type failures, and characterized according to consistent criteria for a number of parameten, such as failure mode, failure area, failure cause, specific valve type (where possible; e g., swing check, lift check), etc. Raw (uncharacterized)
NPRDS data is not generally prefened for analysis purposes due to the lack of some data and inconsistency in data input practices between plants, but for some portions of this analysis, raw failure data for all Palo Verde check valve failures recorded in NPRDS from 1986-1995 was also used.
CEOG Generic Valve Grouns Where possible, it is particularly beneficial to compare check valve performance based on spect6c application. Unfortunately, specific valve application information is rarely available, due to differences in plant designs and terminology and a lack ofinformation avadable from NPRDS. When this type of comparison is desired, it is generally necessary to review plant-speci6c FSARs and attempt to develop some type of generic valve apphcation groups 'Ihis task is usually both time-consunung and frustrating, since compansons can usually only be made among plants with the same NSSS and very mailar system configurations A recent report issued by the Combustion Enginsenng Owners Group (CEOG), CE NPSD-1048,
" Demonstration Project to Apply Risk Based laservice Testing OST) to ECCS Check Valves,"' attempted to dewlop certain generic wa; cation categones for ECCS check valves in a an=hr of CE plants Six utilities with a total of ten plants partscapated in the CEOG study. In order to gather data on ched valves within the scope of the study, CEOG sought to facilitate cross plant comparisons by developing a set of genenc check valve configuration diagrams with a conospondang set of generic check valve groups based on location and fhaction. Since Palo Verde was one of the ten plants participanng in the CEOG study, ORNL was able to cross reference the valves that appeared in both the CEOG report taithe IST relief sequot in order to nyiew both plant spec Sc and industry valve perfonnance based on the genenc 1
Evaluation of Candidate LSSC Check Valves for Risk Based IST Extension at Palo
,wwwmave i
groupings Table 1 lists the CEOG generic group descriptions for those groups of " low risk signi6 cant" Palo Verde valves which also included candidate relief request valws Table 1 CEOG Report CE NPSD-1648 Generie Valve Group Deserb
{
CEOG Description Palo Verde Valve Application Report Gewsp Grou.ps Group B SIT Outlet Check Valves SIEV215, SIEV225, SIEV235, SIEV245 Grcup D LPSIPump Discharge Check Valves SIAV434, SIBV446 Group E LPSI Pump Suction Check Valves SIAV201, SIBV200 Group H LPSI Pump Miniflow Check Valves S!AV451, SIBV448 i
Group J Hot leg huection Line Check Valus SIAV523, SIBV533 Group K Hot leg injection Line to RCS 140p Check SIAV522, SIBV532 Valves 1
Group M HPSI Pump Discharge Check Valves SIAV404, SIBV405
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Group O HPSIPump Miniflow Check Valves SIAV424, SIBV426 Group P Containment Spray Header Check Valves SIAV164, SIBV165 Group R Containment Spray Pump Discharge Check SIAV485, SIBV484 Valves Group S Containment Spray Pump Suction Check SIAV157, SIBV158 valves Group T Containment Spray Pump Miniflow Check SIAV486, SIBV487 Valves i
l
'Ibe 1984 1992 ORNL characterized failure and 1991 population databases were used to review the performance history of the 13 groups of valves listed from the ten plants included in the CEOG report. A a
4 summary of the initial findings is as follows:
i l
InduseyFailures Basedon CEOGReport Generic Application Groups:
No failurer. Groups E, H, O, P, R, S, T.
Group B:
1/ allure; ft. Lucie 2. Borg-Warner 12" DWG 73060 check valve. Valw was stuck open.
Si==ih-I Group D:
4 Ifailure; San Onefre 2. Anchor /Darhng 10" DWG 3454 3 check valve. Broken tack welds and binding between disc skirt and valve stem. Si-aiha' 4
Group J:
Ifailure; Palo Verde 2. Borg-Warner 3" DWG 77700 check valve. LIRT failure. Moderate
^
Group K:
Jfailures-St. Lucie 2. All 3" Westinghouse Model 03000CS8800007 swing check valves.
4 Excessive seat leakage due to steam eremon of the discs. Moderate.
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J i
2 i
Evaluation of Candidate LS8C Check Valves for Risk Based IST Extensi:n at Palo Verde Units 1,2,3 Group M:
6 failures-(l) Palo Verde 2, Borg Warner 4" DWG 79120-1 check valve. Seat leakage.
Moderate.
(5) St. Lucie 2, Anchor / Darling 4" DWG 3527 3 check valve: (1) stuck open-cause unknown-signincant; (1) damaged internal parts resulted in restncted motion de to wear-signi5 cant; (1) stud open due to packing binding-signiScant; (1) internal damage (galling) caused restricted motion - combinanon design pmblem and operating error-signi5 cant; (1) internals galling resulted in restricted motion - material incompatibility and excess tightening of thevalvetotheclosedposition sigm6 cant.
==
Conclusion:==
St. Lacie has had operational problems with this valve due to a combination of causal factors. Failures were related to galhng and bindtog ofintr.*nal parts.
Industry his w Reviewed Usina the 1984-1992 ORNL DMah-Two additional industry wide performanz parameters were also investigated using the ORNL database This review focused on the specinc candutase valves by manufacturer and design.
Industry Failures ByManufacturer/Model Number:
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All Palo Verde valves redewed were manufactured by Borg Warner (now BW/IP).
e All Borg-Warner check valves in the " low safety signi5 cant" groups identi5ed at Palo Verde are swing check valves, exapt those valves in CEOG Group O (SIAV424, SIBV426), which are Borg-i Warner liA check valves.
l No other plants have Borg-Warner valves with model/ drawing numbers corresponding to those at e
Palo Verde, since Borg Warner apparently uses unique drawing numbers instead of model numbers for each plant, so results of a failure history search by model number were inconclusive. Additional design information is nemssary to evaluate failures of spectfic Borg Warner valves.
Industry Failures. Borg-Wamer Valve Failures at All Plants:
Borg-Warner (including Borg Warner Corp., Byron-Jackson Pumps Div./Borg Warner, Nuclear Valve f
Division /Borg Warner, and Weston Hydraulics Div/Borg-Warner) totals 749 valves installed as recorded in the 1991 NPRDS database His makes Borg Warner 13th of over 150 valve manufKimm in terms of actual numher of valves installed. (Note: some mndel numbers listed in the database for Borg-Warner may actually be Kerotest valves, wiuch may differ in design from the other Borg-Warner valves.) Tables 2 8 show the failure distribunons of all Borg Warner check valves in all plants by various parameters, Acm 1984-1992. It should be noted, however, that in order to establish any relative failure rates, the populauon distribution based on each pagameter must also be determined Any conclusions drawn without considenng populauon effects would alman certainly be misleadmg 3
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Evaluation of Candidate LSSC Check Valv;s for Risk Based IST ExtInsign at Palo V;rde Units 1,2,3 Table 2 Industry Borg-Warner Failurt Distribution by Cosaposent Age Group Component Age Group No. Failures Percent of Total (at time of failure)
Borg-Warner Failures
<5 19 63
>=5 and <10 10 33
>=10 and <15 1
3 1
4 Tdk3 Industry Borg-Warner Failure Distribution by Plant Age Group Plant Age Group (at time of No. Failures Percent of Total i
failure)
Borg-Warner Failures
<5 15 50
>=10 and <15 4
13
>=5 and <10 11 37 i
Table 4 Industry Borg-Warner Failura Distribution By Extent of Degradation Extent of Degradation No. Failures Percent of Total
- Borg Warner Failures Moderate 20 67 Significant 10 33 Table 5 Industry Borg-Warner Failust Distribution by Valve Size Group Component Size Group No. Failures Percent of Total Borg-Warner Failures
<=2 15 50
>2 and <=4 13 43
>10 2
7 4
Ev:luation of Candidate LSSC Check Valves for Risk Based IST Extension at Palo Verde Units 1,2,3 Table 6 Industry Borg-Warner Failure Distributien by System ORNL Standard System Name No. Failums AFW 5
Containment isolation 10 Control Rod Drive 3
CVCS 2
HPSI 3
Reactor Recirculation 1
RHR 1
1 Table 7 Industry Borg-Warner Failure Distribution by Manufacturer Model/ Drawing Number and Extent of Degradation l
Manufacturer Model No. Moderate Failures No. Significant Failures
_ (Drawing) Number None listed 0
1 116CCB1-004 3
0 116FCB1005 1
0 l
3-75500 1
0
+
1 4650881 002 0
1 74730 0
1 74750 0
1 75560 0
1 76790 1 1
0 l
77680-1 0
1 77700 1
0 79120 1 1
0 l
80200 0
1 i
82530 3
0 l
CN-0900-1206H-203 0
1 CN-15001009J 255 5
0 CN-15001206J-230 2
0 DWG 73060 0
1 MC 09001206H 101 2
0 l
l l
5 l
Evaluation of Candidate LSSC Check Valves for Risk Based IST Extenshn at Palo VIrde Units 1,2,3 Table 8 Industry Borg-Warner Failurt Distribution by Unit Unit Name No. failures Ext. of Degradation CATAWBA 2 7
Moderate 6; Significant 1 BYRON 2 3
Moderate 2; Significant 1 PALO VERDE 2 3
Moderate 2; Sionificant 1 PERRY 1 3
Moderate 3; Significant 0 COMANCHE PEAK 1 2
Moderate 1: Sionifmant 1 l
MCGUIRE 1 2
Moderate 1; Significant 1 l
MCGUIRE 2 2
Moderate 2; Significant 0 l
ARKANSAS NUCLEAR ONE 2 1
Moderate 0; Significant 1 BRAIDWOOD 2 1
Moderate 1; Sionifmant 0 BYRON 1 1
Moderate 1: Significant 0 ST. LUCIE 2 1
Moderate 0; Significant 1 SUSQUEHANNA1 1
Moderate 0; Signlimant 1 SUSQUEHANNA 2 1
Moderate 0; Signifmant 1 WNP22 1
Moderate 1; Signirmant 0 WOLF CREEK 1 1
Moderate G; Significant 1 Palo Verde Check Valw Failure History Using Raw NPRDS NM1986-1995)
All failures of Palo Verde check valves occurnng during the time frame 19861995 (inclusive) were dmmloaded from NPRDS. (This was done for completeness, since the current ORNL cluk valve l
performaw database contains failures only through 1992, and many of the Palo Verde failures were assumed to have occurred aAct 1992. Palo Verde Units I and 2 began commercial service in 1986, *hile
(
unit 3 began commercial service in 1988.) Failures were manually renewed (and characterized only according to extent of degradation to the component), and external leakage type failures were included for most of the followmg analysis. The following are the results of a cursory evaluation of the 106 NPRDS check valve failures from Palo Verde for this time period:
FiAy.8ve of the 106 NPRDS failure records involved the deferral candidate check valves. Of the 76 valve application groups represented,13 groups expenened repeat failures. There were nine individual valves that experienced repeat failures and three valves that had repeat significant failures. Table 9 shows the nunber of failures by valve apphcation group, unit, and extent of degradation.
Of the 55 failure records samaria8M with the deferral candidate valves,11 involved external leakage
'Ibe remaining 44 failures were reviewed and characterned in terms of extent of degradation in accordance with the criteria used in previous ORNL analyses.u There were 29 (66%) failures deemed moderate in nature and 15 (34%) termed sirih* This ratio is very close to that exhibited industry wide for 1991 and 1992.u The set of 228 deferral canMau valves (76 valve apphcatson groupsAnnit x 3 units) am-latM o
approximately 2100 valve-years of service dunng the pened 1986-1995. If the number of sipihe anilures only is considered, this represents a failure rate of approximately 7x10 '/yr. for the set.
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- **SigniScant" in terms of the degradation to the valve's ability to Anaction. 'Ihese failures include those with broken ard/or detached internals, restncted motion, stuck open, and stuck closed cases.
6 l:
Evtluation cf Candidate LSSC Check Valves for Risk Based IST Extensi:n at Palo l
VIrde Units 1,2,3 Table 9 Distribution of Palo Verde Check Valve Failures (1986-1995) by Unit and Estent of Degradation Valve Application System Unit 1 Unit 2 Unit 3 Total by Group Failures Failures Failures Group _
AFAV137 AFW IS 1
CHAV190 CVCS IS 1
CHBV331 CVCS 2M IM 3
CHEV334 CVCS 1S 2M 3
CHNV154 CVCS 2S 2
CHNV494 CVCS IM 1
DGAV066 Diesel Starting Air 3M 3S IM 7
DGAV067 Diesel Starting Air IM IS 2
DGAV397 Diesel Starting Air IS 1
DGBV068 Diesel Starting Air IM IM 2
DGBV069 DieselStarting Air IM 1
1 GAEVO15 Containment Isolation IM 1M 2
HPAV002 Combustible Gas IM 1
Control NCEV118 CCW IM 1
NPBV004 Combustible Gas IM 1
Control SGAV043 Main Steam IE 1
i SGAV044 Main Steam IE 2S 7
SGEV005 Main Steam 15 1
SGEV642 Main Steam IM 1
i SGEV693 Main Steam IS,lE 2
SIAV404 RHR IS 1
SIAV434 RHR 2E lE 3
SIAV523 RHR IM IM iM 3
SIBV405 RHR IM IM 2
SIBV446 RHR lE 1
SIBV533 RHR IM 2M 1M 4
l M-Moderate failure S-Significaat failure E-Esternal leakage (no internals degradation) l I
l Table 10 shows a list of all candidate Palo Verde ' low safety signi6 cant" check valves application j
groups for IST interval deferral. It also lists the number of failures recorded in NPRDS from 1986-1995, and the number of tcpeat failures. Where applicable, the corresponding CEOG report generic valve apphcation group is also listed.
4 i
7
Table 10 j
Palo Verde RBIST Relief Request Check Valves l
l, Falo Verde RBI5T Repeat Deferral Candidate Failures per Valve ilsted Check Valve Application Failures la NPRDS Application la CEOG Gesup Sytem (1986-1995)
Group ?
Notes Report?
AFAV007 AFW AFAVOIS AFW AFAV137 AFW I (Unit 1) 1 AFBV022 AFW AFBV024 AFW l
AFBV138 AFW I (Unit 1)
CHAV177 CVCS 1 (Unit 1)
CHAVl90 CVCS 1 (Unit 2)
CHAV328 CVCS CHBV331 CVCS 2 (Unit 2), I (Unit 3)
Yes 4
CHEV334 CVCS I (Unit 2),2 (Unit 3)
Yes 4,9 CHEV433 CVCS CHEV440 CVCS CHNV118 CVCS CHNV154 CVCS 2 (Unit 2)
Yes 5
CHNV155 CVCS CHNV494 CVCS 1 (Unit 2) 4 CHNV835 CVCS CTAV016 CTAV037 CTBV020 CTBV038 3 (Unit 1),3 (Unit 2),
i DGAV066 Diesel Starting Air 1 (Unit 3)
Yes 2,6 l
DGAV067 Diesel Starting Air 1 (Unit 1), I (Unit 2)
Yes 3
l DGBV068 Diesel Starting Air I (Unit 1), I (Unit 3)
Yes 3
DGBV069 Diesel Starting Air 1 (Unit 1)
Containment GAEV0li isolation Contamment l
GAEV015 Isolation 1 (Unit 2), I (Unit 3)
Yes 4
Combustible Gas HPAV002 Control 1 (Unit 3)
Combustible Gas HPBV004 Control I (Unit 3)
NCEVil8 CCW I (Unit 2) 4 SGAVD43 Main Steam 1 (Unit 3)
I (Unit 1),2 (Unit 2)
Yes 8
l SGAV044 Main Steam I
SGEV003 Main Steam SGEV005 Main Steam 1 (Unit 3) 10 SGEV006 Main Steam SGEV007 Main Steam SGEV642 Main Steam I (Unit 1)
SGEV652 Main Steam SGEV653 Main Steam SGEV693 Main Steam 2 (Unit 3)
Yes 11 SGEVB87 Main Steam 8
Table 10 Palo Verde RBIST Relief Request Check Valves Falo Verde RBI5T Repeat 1
Deferral Candidate Failures per Valve Listed Check Valve Application Failures in NPRDS Application la CEOG Group Sytem (1986 1995)
Group ?
Notes Report?
SGEV888 Main Steam SIAV157 RHR Group S SIAV164 RHR Group P SIAV201 RHR Group E SIAV404 RHR 1 (Unit 1)
Group M SIAV424 RHR Group O SIAV434 RHR 2 (Unit 1), I (Unit 2)
Yes Group D SIAV451 RHR Group H SIAV485 RHR 1 (Unit 1)
Group R SIAV486 RHR Group T SIAV522 RHR Group K 1 (Unit 1), I (Unit 2),
SIAV523 RHR 1 (Unit 3)
Yes 4
Group J SIBV158 RHR Group S SIBV165 RHR SIBV200 RHR Group E SIBV405 RHR 1 (Unit 1), I (Unit 2)
Yes 4
Group M SIBV426 RHR Group O SIBV446 RHR 1 (Unit 2)
Group D SID'.'448 RHR Group H SIBV484 RHR 1 (Unit 1)
Group R SIBV487 RHR Group T SIBV532 RHR Group K 1 (Unit 1),2 (Unit 2),
SIBV533 RHR 1 (Unit 3)
Yes 2
Group J SIEV215 RHR Group B SEV225 RHR Group B SEV235 RHR Group B SEV245 RHR Group B SPAV041 ESW SPBV012 ESW WCEV039 DGAV3%
Diesel Starting Air DGBV4%
Diesel Starting Air DGBV497 DieselStarting Air DGAV397 Dusel Startmg Air 1 (Unit 2) 7 9
EvCluation of Candidate LSSC Chect Valves for Risk Based IST Ext 0nsion at Palo -
Verde Units 1,2,3 4
i f
Table le Notes:
j 1
Stuck open failure due to corrosion and normal wear.
2 Repost failures due to pitting and corramon caused by debris and moisture buildup in system.
Repeat " failed to seat" failures.
3 3
Repeat leakage and bindmg failures attributed to corrosion buildup in system and normal operational and environmental wear / aging.
4 Internal leakage'due to normal wear or aging / cyclic fatigue.
5 2/17/95: leakage past seat attributed to wear. Disc stud broken due to cyclic fatigue.
3/27/95: Puces of valve internals found to be aussing, including : 2 inch length of the disc stud with the welded nut, stud sleew, and washer. Valve would not have functioned properly. Failure attnhted to inadequate design and cyclic fatigue.
i 6
Repeat stuck closed failures.
i 7
Broken hinge arm and loose internal parts attnhted to possible cyclic fatigue.
S Repeat hinge pin failure due to wear.
9 Internal leakage caused by abnormal wear / cyclic fatigue.
10 Stuck open condition due to cyclic conditions.
11 Valve binding (restncted motion) due to inadequate assembly.
)
0 10
Evaluation of Candidate LSSC Check Valves for Risk Based IST ExtInsion at Prio Verde Units 1,2,3 Conclusloes Thirteen of the genenc valve appbcation groups listed in the CEOG RBIST report contsinM valves for which Palo Verde has imp '.d IST relief. Of these, sewn groups had no recorded failures for any of the ten plants in the CEOG study, while six gmups did haw failures recorded in the ORNL failure database danag the time pened 1984-1992. The most failures occurred in genenc Group M, HPSI pump discharge check valves t
l Failure histones based on valve manufacturer (Borg Warner) and manuf=eturer/model numher were also j
reviewed with generauy inconclusive results. Since this particular manufacturer uses unique drawing numbers rather than model numbers for its valves, making direct comparison based on design is difBcult l
without additional information Some other industry analyses based on vanous parameters related to Borg-Warner check valves were also presented.
Potentially the most signi5 cant Badmgs resulted from a brief review of the 106 raw NPRDS failure records for Palo Verde Units 1,2,3 dunng the time penod 19861995. Fifty five of the 106 NPRDS failures involved deferral candulate valves nitteen valve appliation groups experienced repeat failures t
l across all three units. Nine individual valves expenenced repeat failures, and three valves had repeat signiScant failures, it is important to note that at least 35 of the 44 failures involving internals l
degradation were attributed by Palo Verde (in the NPRDS narratives) at least in part to some age related faDure mechanism such as " wear," " cyclic fatigue," or " debris buildup " Dese types of failure causes must be considered when evaluating whether to extend inservice test).ng intervals.
De system of service for candulate IST deferral should also be considered. At least 75 percent of the deferral candidate " low safety significance" valws are located in either AFW, Diesel Starting Air, Containment Isolation, CCW, Main Steam, or RHR systems, which have been shown to have some of the i
highest relative failure rates by system for sigm6 cant failures (in terms of component degradation)?
l It is not clear from the performance data reviewed so far that IST interval extension isjustified for all the components listed in the Palo Verde relief request. Although both the Palo Verde relief request itself and l
the CEOG report identify specific component performana as a critical consideration in the determination ofboth level of safety signi% and length ofinterval extension, how this criteria was applied is not l
straightforward Neither damment c.ites either plant-specific or industry data as their source for check valve failure rates used as input for the probabilistic analyses. Inne4 it appears that " generic" data was used as input for all the probabilistic analyses, which would fail to take into arenant any of the performance history parameters reviewed herein.
la order to fullyjustify IST interval extenson for any of the componenta listed as ennautases for deferral in the Palo Verde relief request submittal, a further review of both operational performance data and other plant practices should be undertaken. For example, it might be prudent to ask, " What meannes have been taken to ensure that the Diesel Starting Air system is free of corremon and debns caused by moisture inade the systemT Dis is especially important, since from previous industry-wide sihL." it has been shown that Diceel Starting Air check valves have been especially prone to failure (signifcart failure: both stuck open and stud closed)ikom this problem. De current ORNL review has also shown that several of the condulate Palo Verde valves in the Diesel Starting Air system have failed repeatedly for the same reason. Other supporting programs such as plant maintenance and preventive maintenanne should be reviewed also when 9 - T-1-g IST deferral, since component eism v and longevity are highly We upon these practices l
1
!1
Evaluation of Candidate LSSC Check Valves for Risk Based IST Extension at P:lo Verde Units 1,2,3 l-me c.
I l
1 Combustion Engineenng Owners Group (CEOG), CE NPSD-1048," Demonstration Project to Apply Risk Based lasemce Testing OST) to ECCS Check Valves," June 1996, 2 Oak Ridge National Laboratory, NUREG/CR-5944, Vol. 2,"A Charactenzation of Check Valve 1
Degradation and Failure Experience in the Nuclear Power Industry - 1991 Failuru,"-July 1995.
3 Oak Ridge National Laboratory, ORNUNRC/LTR-96/11, "A Charactenzation of Check Valve Degradation and Failure Experience in the Nuclear Powr Industry.1992 Failures," June 1996.
i h
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12
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1._
OAK RfDGE NATIONAL LA2 ORATORY
< MANAGF.D SY LOCKHEED MARTIN ENERGY RESEARCH CORPORATION PHONE:(423) 5744734 FOR THE U S. DEPARTMENT OF ENERGY FAK:(423) 5764493 l PosiorFct tox 300s
[ onanmaa.tusreatme January 9,1997' Jerry E. Jackson U. S. Nuclear Regulatory Commission
. MS T10 E10 Washington,D.C. 20555
Dear Mr. Jackson:
As we discussed in the October 8,1996 meeting with NRC personnel, selected Comanche Peak check valves listed in Enclosure 3 to TXX-%371 have been reviewed relative to failure history. The time period covered was from 1990 through 1995.
Comanche Peak has requested IST extension from their current code requirements (usually quarterly) to an
- interval of 6 years on approximately 380 " low safety significant" check valves. In an effort to provide information needed to evaluate potential candidate risk based inservice test (RBIST) check valves at Comanche Peak for extended IST intervals, Oak Ridge National Laboratory (ORNL) has done a briefreview of the available NPRDS failure acords and performance data for the check valves in question. The results of this review are provided in the attached summary report.
An analysis was done on check valve failure data obtained from NPRDS for Comanche Peak Units 1 and 2 from 1990 through 1995. Unit I began commercial service in 1990, while Unit 2 began commercial operation in 1993. " Raw" NPRDS failure narratives were reviewed and characterized according to the
- criteria used in development of the ORNL check valve performance database. The ORNL database itself was not used for this analysis since it covers only the time period 1984 through 1992, which would have failed to incorporate most of the Comanche Peak operating experience. Comanche Peak check valve failure experience was reviewed according to several parameters, including severity of degradation (to the. valve itself), system, failure cause, and component repeat failures. A comparison of valves with failure records -
in NPRDS with the deferral candidate valves was also made. Only 33 failure records were included in the NPRDS database (as of November 1996) for failures occurring from 1990 through 1995. Therefore, due to the small failure population, all mcords were included in the analysis. Also due to the limited failure data cvailable, a detailed comparison to overall' industry performance experience was not made at this time.
Of the 33 failure records recorded in NPRDS for Comanche Peak check valves from 1990-1995, all but 2 cf the failed valves are included in the list ofIST deferral candidates. Nine ef the thirty-three failures involved repeat failures (considering both units). Two individual components (2FW-0013 and 2DO-0258)
I had repeat significant failures. Diesel Lube Oil valve DO-0258 had a total of three significant failures, considering both units.
~ binging cSciencelo Bfe a
9? w.w ro %,,e
l',
. Jerry E. Jackson January 8,1997 Pag:2 It is important to understand that due to the small number of failure records available for Comanche Peak l
check valves during the relatively short analysis period, few statistically meaningful results can be derived.
The data does not, however, at this point suggest any abnormal failure patterns or causes. By the same argument, little data is currently available to validate IST interval extension or to evaluate the effect of L
interval extension on check valve perfonnance. Further collection and analysis of performance data over an extended operating period would be necessary to more accurately evaluate the effects of changes in the IST program.
In the review of current reliefrequests for Comanche Peak check valves, it might be prudent to question both the nature of(and corrective measures taken with regard to) the failures which have occurred as well as the I
source (s) of data that were used as input to risk-based calculations. For example, it might be reasonable to question the failure experience of five CCW stop check valves that involved the valves' sticking closed due to... " corrosion product accumulation between plug and bore during long periods ofinactivity. Periodic j
stroking of valve (s) was less than adequate.' Quarterly stroking of(the) valve (s) had to be initiated to prevent
{
recurrence." Additionally, considering the limited nature of Comanche Peak operating experience and data, the sources of component failure rates and other analysis inputs might be questioned.
Also, in consideration of the length of the IST interval extension requested (6 years), it is important to note that of the 27 internals-related failures,16 involved some type of age-related failure mechanism such as debris accumulation or wear. Of the 16 significant failures,8 were age-related. Although this examination was rather cursory in nature, ample evidence exists to question the technical validity of extending the 1
inspection interval for all the requested check valves without assurance that corrective actions have been taken and/or inclusion of condition monitoring on some of the check valves. Unavailabilities of all check valves in applications susceptible to aging should be simultaneously increased by the appropriate factor to cover the simultaneous effects of aging. This should be completed to show that the impact on risk remains low even for unmitigated aging.
We hope that this information will be useful to you. Should you need additional information, we would be glad to provide further assistance.
Sincerely, A. B. Poole i
ABP:jke Enclosures l
l cc/ enc:
P. L. Campbell, NRC D. C. Fischer, NRC W. E. Vesely, SAIC J. Colaccino, NRC W. C. Gleaves, NRC J. P. Vora, NRC K. L. McElhaney F. Grubelich, NRC R. H. Wessman, NRC
i Evaluation of Candidate LSSC Check Valves for Risk Based IST Extension at Comanche Peak Units 1,2 t
4 1
N i
K. L. McElhaney j
Oak Ridge Nationallaboratory Oak Ridge, Tennessee j
January 6,1997 s.
l NRC Job Code W6324 o
e S a p d; o l c c '/ 9 A p.
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-. -. _ - = - - - - -- - - - -. -
Ev luatirn cf Candidate LS8C Check V lves frr Ri:k Based IST Extsnsi n ct Comanche Pe k Units 1,2 l*
Background
Comanche Peak Steam Electric Station has recently submitted to the NRC a request for relief from the Inservice Test (IST) intervals curready required by the ASME Code for certain check valves based on a probabilistic analysis of the valves
- importance to safety. In theory, this analysis methodology results in the ranking of components into two basic categories, those of high safety significance and those with low safety significance. The goal is to ensure that the components more important to plant safety are to be tested in a manner that provides a high level of assurance of their operability. Another goal of the Risk Based approach (RBIST) is to show that IST intervals may be extended beyond the current requirements without resulting in signi5 candy increased safety risks. One consuleration in this type of analysis is component performance history, both from the specific plant as well as from ab fndustry perspective.
Comanche Peak has requested IST extension from their current Code requirement < (usually quarterly) to an interval of 6 years on appronmately 3g0 " low safety sigmficant" (LSSC) check valves. In an effort to provide information needed to evaluate potential e=adidate check valves at Comanche Peak for extended IST intervals, Oak Ridge National laboratory (ORNL) has done a brief review of the available performance data for the valves in question. The following is a summary report on that analysis.
Analysis Results An analysis was done on check valve failure data obtained from NPRDS for Comanche Peak Units I and 2 from 1990 through 1995. Unit I began commercial service in 1990, while Unit 2 began coes.ercial operation in 1993. " Raw" NPRDS failure narratives were reviewed and charactertzed according to the criteria used in development of the ORNL check valve performance database The ORNL database itself was not used for this analysis since it covers only the time period 1984 through 1992, which would have failed to incorporate most of the Comanche Peak operating expenence. Comanche Peak check valve" failure experience was reviewed according to several parameters, including severity of degradation (to the valve itself), system, failure cause, and component repeat failures. A comparison of valves with failure records in NPRDS with the deferral candidate valves was also made. Only 33 failure records were included in the NPRDS database (as of Nei.As 1996) for failures occurring from 1990 through 1995.
Derefore, due to the small failure population, all records were included in the analysis (i.e., external leakage type failures were included). Also due to the limited failure data avadable, a detailed comparison to overall industry performance experience was not made at this time.
Coneende Plank deck velvefeUnre sapersence-1H0-1M3 Of the 33 NPRDS check valve failure records sysdable for 19901995, the failure distnhation according to extent ofdegradation is shown in Table 1:
Table 1 All Comanche Peak Check Vahe Failurus by Estest of Degradation Extest of Degradation No, Failures Moderate 11 Significant 16 Externalleakage 6
i l
Ev:luati:n of COndidate LSSC Check Vrives far Risk Based IST Ext:nsinn Et Comanche P;;k Units 1,2
" Extent of degradation" refers to the effect of the failure on the ability of the component to perform one or more ofits design functions, not to any resultant effect on train, system, or plant operation. For a check valve, therefore, a s/gnificant failure would be one in which the valve either stuck open or stuck closed, exhibited mechanical binding, or had loose or detached internal parts. External leakage (e.g., bonnet or flange leakage) type failures were not originally included in the ORNL check valve database, but were identified for this analysis for the purpose of providing an overall representation of check valve performance at Comanche Peak.
l If only moderate and significant failures are considered, then for Comanche Peak during the study period ofinterest, 59% of the check valve failures were sigm6 cant.
- Ibis compares with an industry average of approximately 35% significant failures for 1991 1992 (excluding external leakage type failures).
Further examination of the Comanche Peak failures indicates that many of the significant failures were of
. the type to be expected in a new plant, however. Table 2 shows the failure distribution by extent of degradation and failure cause.
Table 2 Comanche Peak Check Valve Failure Distribution by Extent of Degradation and Failure Cause
- Failure Cause No. Moderate Failures No. Sinnificant Failures l
Abnormal wear 1
Abnormal wear, 1
1 design problem Abnormal wear, I
procedur: problem Foreign material 5
Foreign material; 2
design problem Foreign material; 5
procedure problem
~
Maintenance problem I
Procedure problem; 1
improperinstallation Manufacturing defect 4
Unknown 3
2 Normal wear 1
From Table 2 it is apparent that of the 27 failures involving internals degradation (i.e., excluding external leakage failures), 9 were related to " infant" type,,,h 'Wiar
'-wdug defects or misintenance, installation, or design errors. Seven of the sixteen sigmficant failures were related to these causes Also, in canaideration of the length of the IST interval enannian i+; - r t it is imponant to note that of the 27 internals-related failures,16 involved some type of age-related failure nwchamam such as debns aminnilatian or wear. Of the 16 sigmficant failures,8 were age-related In order to prende a more dotatied review, Table 3 lists all failures by =npanant ID and extent of l
degradation. Repeat failures are also identifiarl A summary of the agnificant and repeat failure records is provided(see notes).
i h
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l
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Ev luati:n of Crndidate LSSC Check Vrives f:r Risk Bas d IST Ext:nsicn at Comanche Fc"k Units 1,2 Table 3 Comanche Peak Check Valve Fallures by Component ID
~
Component Valve Type System No. failures / Extent Repeat Valve on RBIST Notes ID of degradation
- failures candidate (both deferrallist?
malts)?
I AF-0086 AFW IE Yes IAF-0093 AFW IS
' Yes 1
1 AF 0098 AFW IM Yes I AF-0101 Swing AFW IS Yes 2
ICA 0016 Containment 2M Yes Yes 3
laolation ICC 0657 Stop CCW IS Yes 4
ICC 0831 Lift CCW 2M Yes Yes 9
ICC-1075 Stop CCW IS Yes 4
ICC-1076 Stop CCW IS Yes 4
~
._1CS-8443 Lift CVCS IM ICT 0013 Containment IE Yes
~~
Spray ICT 0047 Containment IE Yes Spray ICT 0063 Containment IE Yes Spray ICT 0077 Containment IE Yes Spray
]
Spray I
IDO4258 Diesel Fuel Oil 1S Yes Yes 5
f IFW-0076 Tilting dise Feedwater IS Yes 6
IFW4088 Tilting disc Feedwater IS Yes 7
1S18968 Lift Containment 2M Yes Yes 9
1 solation 2CA 0016 Ca=*=inawat IM Yes Yes 3
i isolation 2CC4831 Lift CCW IS Yes Yes 11 2CS4368C Lift CVCS IM Yes 2DO 0258 Diesel Lube 2S Yes Yes 8
Oil j
i 2FW 0013 Tilting dise Feedwater 2S Yes 12 2SI8968 Lift Caa'=ia-t IM,lS Yes Yes 10 l
Isolation i
- E-Externalleakage, M-Moderate, S-Significant j
1 l
4 3
Ev luati:n of Candidate 1.SSC Clwck V lves f:r Risk Based IST Extensian at Comanche Peak Units 1,2
('
Table 3 notes (taken from NPRDS failure narrativest i
Valve disc held offits seat due to mechanical interference between disc counterweight and valve body. Manufacturmg defect.
2 Creck in valve seat circumferential seal weld. Manufactunng defect.
3 Repeat failures due to debris buildup on valve seat resulting from moisture in the system.
4 Stop check valve failed open due to corrosion product accumulation between plug and bore during long periods ofinactivity. Penodic stroiang of valve was less than adequate. Quarterly strolung of valve had to be initiated to prevent recurrence 5
Valve disc detached from hinged connecuon at valve body due to combination of repeated cycling and high reseadng pressure (Clow Corp. " FIG $3").
6 Vendor supplied valve with incorrect angle clearance, causmg disc to bind on side suppons prior to fully closing.
7 Inadequate assembly procedure resulted in improper installation of torsion springs. Disc would not fully contact the seat.
1 8
Repeat failures due to wear and slammmg of viton valve seat / gasket on metal sealing surface i
resulting in teanns of(soft) viton seat material. " Valve inadequately designed for application."
(Clow Corp " FIG 53").
9 Repeat internalleakage failures.
10 Repeat failures due to galhng, seat cocking.
i 11 Stuck open due to " bad seat and disc." Failure cause unknown.
12 Repeat stuck open failures. (1) Dise lodged against seat with pivot and retaining pins minemg Interference weld secunng the retaming pin i==da==** Maintena-error. (2) Bindmg at disc stop contact area prevented closure Ma==" ring defect.
De 33 check valve failures were distributed across 8 systems as shown in Table 4. Figure 1 illustrates the failure distribuuon by failure cause and system.
Table 4 Distribution of th==eh* Peak Check Vahe Failures by System and Extent of Degradation System Externalleakane Moderate m =ifie=_=*
AFW I
I 2
l CCW 2
6 Coe*al==*=t lealatian 6
I Caseal====t Soray 5
CVCS 2
Diesel Fuel Oil 1
l Diesel Labe Oil 2
1 I
~
4
Ev:luati:n cf Crndidita LSSC Check Vcives far Risk Based IST Ext:nsi:n ct Comanche P.ck Units 1,2 Failure cause 3 Abnormal wear E Design deficiency E Procedural problem B Foreign material B Maintenance error Elnstallation problem EManufacturing defect E Unknown j
B Normal wear D Externalleakage t-Hr i l-:l,,,Ill 0
i i
'i r
i i
AFW CCW Containment Containment CVCS DW Fuel Diesel t.ube Feedwater Isolation Spray Oil Oil Figure 1 Comanche Peak check valve failure distribution by failum cause and system Conclusions Of the 33 failure records recorded in NPRDS for Comanche Peak check valves from 1990-1995, all but 2 of the failed valves are included in the list ofIST deferral candidates. (Table A 1 in the Appendix lists all the deferral candidate check valves by unit and system.) Nine of the thirty-three failures involved repeat failures (considering both units). Two individual components (2FW 0013 and 2DO 0258) had repeat i
significant failures. Diesel Lube Oil valve DO-0258 had a total of three significant failures, considering both units.
i It is important to understand that due to the small number of failure records anilable for Comanche Peak check valves during the relatively short analysis period, few statistically meamngful results can be derived. The data does not, however, at this point suggest any abnormal failure patterns or causes. By the same argument, little data is currently available to validate IST interval extension or to evaluate the effect ofinterval extension on check valve performance. Further collection and analysis of performance data over an extended operating period would be necessary to more accurately enluate the effects of changes in the IST program.
In the review of current relief requests for Comanche Peak check vah es, it might be prudent to question both the nature of(and conecuve measures taken with regard to) the failures which have occurred as well as the source (s) of data that were used as, input to risk-based calculations. For example, it might be reasonable to question the failure experience of five CCW stop check valves that involved the ulves' sticking closed due to... " corrosion product -=l= tion between plug and bore during long periods of inactivity. Periodic strolang of valve (s) was less than alequate. Quarterly strokmg of(the) valve (s) had to be initiated to prevent recurrence " AdditionaEy, considering the limited nature of C-ha Peak cperating expenence and data, the sources of cosaponent failure rates and other analysis inputs might be questioned.
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Ev:.luati:n cf Candidate LSSC Check V.lves far Ri:k Based IST Extensi:n ct Comanche Peak Units 1,2 References 1
Oak Ridge National Laborator). NUREGCR 5944, Vol. 2 "A Characterization of Check Valve Degradation and Failure Experine in P : Nuclear Power Industry - 1991 Failures," July 1995.
2 Oak Ridge National laboratory, ORN11NRC/LTR-96/11, "A Characterization of Check Valve Degradation and Failure Experience in the Nuclear Power Industry-1992 Failures," June 1996.
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i Evaluati n of Candidate LSSC Check V:lves f:r Risk Based IST Ext:nsi:n ct i
Comanche Peak Units 1,2 i
APPENDIX i
Table A 1 Camawk Peak Risk Based IST Deferral Candidate Check Valves Comanche Peak RBIST Unit (s)
System Failures in NPRDS Deferral Candidate Check (1990-1995) j Valves' 4
1,2AF 0014 1,2 AFW j
1,2AF 0024 1,2 AFW 1,2AF 0032 1,2 AFW 1,2AF 0038 1.2 AFW 1,2AF-0051 1,2 AFW l
1,2AF 0065 1,2 AFW i
1,2AF 0075 1,2 AFW 1,2AF 0078 1,2 AFW l
1,2AF 0083 1,2 AFW j
1,2AF 0086 1,2 AFW Unit 1 (IE) 1,2AF-0093 1,2 AFW Unit I (IS) 1,2AF 0098 1,2 AFW Unit 1 (IM) 1,2AF-0101 1,2 AFW Unit 1 (IM) 1,2AF 0106 1,2 AFW IAF 0215 1
AFW IAF-0217 1
AFW IAF 0219 I
AFW 1,2AF-0221 1,2 AFW 1,2AF 0222 1,2 AFW IAF 0223 1
AFW 2AF 0224 2
AFW-1AF 0224 1
AFW 2AF 0223 2
AFW 2AF 0227 2
AFW 2AF 0226 2
AFW 1,2AF 0228 1,2 AFW 1,2AF 4229 1,2 AFW IAF 0230 1
AFW 2AF 0231 2
AFW 2AF 0230 2
AFW 1,2AF 0232 1,2 AFW 1,2AF 0233 1,2 AFW 1,2AF 0234 1,2 AFW 1,2AF 0235 1,2 AFW 7
Ev luati n cf Candidate LSSC Check Valves f:r Risk Based IST Extensign ct
{
Comanche Peak Units 1,2 Comanche Peak RBIST Unit (s)
System Failures in NPRDS I
Deferral Candidate Check (1990-1995)
Valves j
1,2CC 0003 1,2 CCW L
1,2CC 0004 1,2 CCW 1,2CC-0031 1,2 CCW l
{
2CC 0371 2
CCW 2CC 0372 2
CCW 2CC 0373 2
CCW j
2CC 0374 2
1,2CC 0646 1,2 CCW
}
1,2CC 0657 1,2 CCW Unit 1 (15) 1,2CC 0687 1,2 CCW j
1,2CC 0694 1,2 CCW i
1,2CC 0713 1,2 CCW
[
1,2CC 0831 1,2 CCW Unit I (2M);
Unit 2 (IS) i ICC-1075 1
CCW Unit 1 (IS)
]
i ICC-1076 1
CCW Unit 1 (IS) l l
ICC-1077 1
CCW Unit 1 (IS) i ICC-1078 1
CCW Unit I (IS) j ICC-1079 1
}
ICC-1080 1
CCW l
ICC 1081 1
CCW j
ICC 1082 1
2 CCW I
2CC-1092 2
)
2CC 1093 2
{
1,2CH 0300 1,2 rantainnwnt Isolation j
1,2CH 0301 1,2 rantainnent Isolation i
XCS 0037 Conunon CVCS I
XCS 0039 Common CVCS I
ICS4041 Common CVCS XCS 0044 en n. nan CVCS 1,2CS 8180 1,2 CVCS
{
1,2CS-8350A 1,2 CVCE 1,2CS-8350B 1l2 CVCS 1,2CS-8350C 1,2 CVCS 1
1,2CS4367A 1,2 CVCS 1,2CS4367B 1,2 CVCS l
1,2CS-8367C 1,2 CVCS-
}
1,2CS4367D 1,2 CVCS 1,2CS4368A 1,2 CVCS
)
1,2CS4368B 1,2 CVCS i
1,2CS4368C 1,2 CVCS Unit 2 (IM) 8
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Evaluatirn of Candidate LSSC Check Valves f:r Risk Based IST Ext:nsi:n ct Comanche P:ak Units 1,2 Comanche Peak RBIST Unit (s)
System Failures in NPRDS Deferral Candidate Check (1990-1995)
Valves 1,2CS-8368D 1,2 CVCS 1,2CS-8377 1,2 CVCS i
1,24378A 1,2 CVCS 1,24378B 1,2 CVCS 1,2-8379A 1,2 CVCS 1,24379B 1,2 CVCS 1,24381 1,2 CVCS 1,2CS-8442 1,2 CVCS 1,2CS-8473 1,2 CVCS 1,2CS-8480A 1,2 CVCS
_1,2CS4480B 1,2 CVCS 1,24481A 1,2 CVCS 1,24481B 1,2 CVCS 1,2CS4487 1,2 CVCS j
1,24497 1,2 CVCS 1,2CT 0013 1,2 Containment Spray Unit 1 (IE) 1,2CT 0020 1,2 Containment Spray 1,2CT 0025 1,2 Containment Spray 1,2CT-0031 1,2 Containment Spray 1,2CT 0042 1,2 Containment Spray 1,2CT-0047 1,2 Containment Spray Unit 1 (IE) 1,2CT-0048 1,2 Containmerit Spray 1,2CT-0063 1,2 Containment Spray Unit 1 (IE) 1,2CT-3064 1,2 Contamment Spray 1,2CT 0065 1,2 Containnent Spray 1,2CT 0072 1,2 Contamment Spray 1,2CT 0077 1,2 Contamment Spray Unit 1 (IE) 1,2CT.0082 1,2 Containment Spray 1,2CT-0094 1,2 Containment Spray Unit 1 (IE) 1,2CT-0142 1,2 Containment Spray 1,2CT 0145 1,2 Containment Spray 1,24,T-0148 1,2 C='aia~at Spray 1,2CT4149 1,2 C='aia~nt Spray 2DD-0002 2
Demineralized and ReactorMakeup Water 1,2DD 0006 1;2 Demi-liwand Reac:or Makeup Water 2DD 0008 2
Deminerahzed and ReactorMakeup Water 2DD4009 2
Demineralized and Reactor Makeup Water 9
i Ev:luation of Candidate LSSC Check Valves frr Risk Based IST Extensinn ct Comanche Park Units 1,2 Costanche Peak RBIST Unit (s)
System Failures in NPRDS Deferral Candidate Check (1990 1995)
Valves 1,2DD-0016 1,2 Demineralized and Reactor Makeup Water 1,2DD 0018 1,2 Demineralized and j
Reactor Makeup Water XDD-0044 Common Demmeralized and i
Reactor Makeup Water XDD-0048 Commen Demmerahzed and Reactor Makeup Water i
i IDD-0064 1
Demineralized and Reactor Makeup Water IDD 0065 1
Damineralized and Reactor Makeup Water IDD 0066 1
Dominershzod and Reactor Makeup Water 1,2DO 0004 1,2 DieselFuel Oil 1,2DCM005 1,2 Diesel Fuel Oil 1,2DCM016 1,2 Dwee! Fuel Oil 1,2DCM017 1,2 Diesel Fuel Oil 1,2DCN)049 -
1,2 DieselFuel Oil IDCM050 1
DicaelFuel Oil 2DO 0052 2
Diesel Fuel Oil 1,2DCM058 1,2 Dicent Fuel Oil 1,2DCM059 1,2 Diesel Fuel Oil 1,2DO 0060 1,2 Diesel Fuel Oil 1,2DO 0061 1,2 Diesel FuelOil 1,2DO 0062 1,2 Diesel Fuel Oil 1,2DO 0063 1,2 Diesel Fuel Oil 1,2DO 0064 1,2 Dicael Fuel Oil 1,2DCM065 1,2 DieselFuel Oil 2DO 0074 3
Diesel Fuel Oil 2DCM075 2
Diesel Fuel Oil 2DCM076 2
Diesel Fuel Oil 2DCM077 2
Diesel Fue1 Oil 1,2DCM104 1,2 DieselFuel Oil 1,2DO 0157 1,2 Diesel Fuel Oil 1,2DCM158 1,2 Dusel Fuel Oil 1,2DCM204 1,2 Diesel Fuel Oil 1,2DO 0257 1,2 Diesel Fuel Oil 1,2DO 0258 1,2 Diceel Fuel Oil Unit I (IS);
Unit 2 (25) 10
-.m.
.. _ _ _ _ _. _ _ _ _ _. - _ _ _ _ _ _.. _.. _. _ _. _ _ _. _ _ _.. _ _. _... _. _.. _ _ ~ _ _.. _ _. _ _ _. _. _. _ _ _ _ _ _
Ev:luatirn of Candidate LSSC Check V lves far Risk Based IST ExtInsi:n at i-Comanche Peak Units 1,2 Comanche Peak RBIST Unit (s)
System Failures in NPRDS 1
Deferral Candidate Check (1990-1995)
Valves 1,2FW-0070 1,2 Feedwater 1,2FW 0076 1,2 Feedwater Unit I (IS) l 1,2FW 0082 1,2 Feedwater -
l 1,2FW 0088 1,2 Feedwater Unit 1 (IS) j 1,2FW4191 1,2 Foodwater 1,2FW 0192 1,2 Feedwater 1,2FW4193 1,2 Feedwater j
1,2FW 0194 1.2 Feedwater i
1,2FW4195 1,2 Feedwater 1,2FW 0196 1,2 Feedwater
- 1,2FW 0197 1,2 Feedwater 1,2FW 0198 1,2 Feedwater j
1,2FW 0199 1,2 Feedwater 1
1,2FW 0200 1,2 Feedwater 1,2FW 0201 1,2 Feedwater j
l 1,2FW 0202 1,2 Feedwater i
1,2MS 0142 1,2 Main Steam 1,2MS4143 1,2 Main Steam I
2MS 0663 2
2MS-0664 2
Main Steam 2MS 0665 2
Main Steam 2MS4666 2
Main Steam 2MS 0667 2
Main Steam 2MS 0668 2
Main Steam 2MS 0669 2
Main Steam 2MS 0670 2
Main Steam IMS 0680 1
Main Steam IMS 0681 1
Main Steam IMS 0682 1
Main Steam IMS 0683 1
Main Steam IMS 0684 1
Main Steam IMS 0685 1
Main Steam IMS 0686 1
Main Steam IMS4687 1
Main Steam 1,24730A 1,2 RHR 1,24730B 1,2 RHR XSF 0003 ranman Spent Fuel Pool Coohng System XSF 0004 ramman Spent Fuel Pool Cooling System XSF4160 ran=an Spent FuelPool Cooling System XSF4180 Common Spent FuelPool Cochng System 1,24841A 1,2 RHR 1,24841B 1,2 RHR 11
i
. Evaluati:n of Candidate 1.88C Check V:lves f:r Risk Based IST Extensi:n at Comanche Peak Units 1,2 raamanche Peak RBIST Unit (s)
System Failures in NPRDS l
Deferral Candidate Check (1990-1995)
Valves i
1,24890A 1,2 l
1,24890B 1,2 1,2SI4900A 1,2 HPSI 1,2S14900B 1,2 HPSI l
1,2S14900C 1,2 HPSI
_l,2SI4900D 1,2 HPSI l
1,2S14905A 1,2 HPSI l
- 1,2SI4905B 1,2 HPSI-
~
1,2SI4905C 1,2 HPSI
}
1,2SI4905D 1,2 HPSI
}
1,2S14919A 1,2 HPSI 1,2SI4919B 1,2 HPSI l
1,24922A 1,2 HPSI i'
1,24922B 1,2 HPSI 1,24949A 1,2 HPSI 1,24949B 1,2 HPSI 1,24949C 1,2 HPSI 1,24949D 1,2 HPSI 1,24958A 1,2 RHR i
1,24958B 1,2 RHR l
1,2S14968 1,2 enntainenent Isolation Unit 1 (2M);
Unit 2 (IM.lS) 1,24%9A 1,2 HPSI 1,24%9B 1,2 HPSI 1,2VD 0003 1,2 Vents and Drains 1,2VD 0004 1,2 Vents and Drains 1,2VD 00ll 1,2 Vents and Drains 1,2VD 0012 1,2 Vents and Drains 1,2CA 0016 1,2 canenininent inname=
Unit 1 (2M);
Unit 2 (IM) 1,2CH 0024 1,2 ennemininen' Isolation 1,2CI 0030 1,2 Containsment Isolation E-Externalleakage M-Moderate S.%gninennt
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e 12