05000361/LER-1992-009, :on 920614,discovered That Salt Water Cooling Pump P112 Emergency Seal Water Isolation Valve MU019 Closed. Caused by Valve Misalignment on 920528.Water Supply Restored & Event Reviewed by Engineering Personnel
| ML20127L367 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 11/19/1992 |
| From: | Krieger R SOUTHERN CALIFORNIA EDISON CO. |
| To: | |
| Shared Package | |
| ML20127L366 | List:
|
| References | |
| LER-92-009, LER-92-9, NUDOCS 9211240056 | |
| Download: ML20127L367 (10) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(x) |
| 3611992009R00 - NRC Website | |
text
l LICENSEE EVENT REPORT (LER)
Facility hame (1)
Docket Ntsnber (2)
_Pene f3)
SAN ONOFRE NUCLEAR S pj,R,ATING STAT 10N UNil ?
O! $! O! Of O! 3! 61 1 1lof 1 0 Title (4)
MlE AllGNMENT OF UNIT 2 SALT WATER COOLING PUMP P112 EMERGENCY SEAL WA1ER SUPPLY ISOLATION VALVE FVFWT BATF ( 5 's IF# HyyRFD (M Rf' Port BATF (7)
OTHFR FAElt1'lFC !WVolVFD (R)
"I N'
E*CII *
//f Nf h
yf Month Day Year Month Day i Year year jj SONGS. UNIT 3 O! 5! O! O! O! 3! 61 2 O!6 1!4 912 9!2 0!OI9 0!1 I
f 01 SI 01 O! O! ! !
Thlh REPORI 15 SUBM fiED PURSUANT TO 'HE REQUIREMENIS OF 10CFR OPERAllNG
{Qeck one or more of the f ol Lowing) (11)
MODE (9) 1 PowtR M 2(b) 50.36(c)(1)
- 50. 73(a)(2)(v) 73.71(b) 20.405(c) 50.73(a)(2)(Iv) 20.405(a)(1)(i) 73.71(c )
LEVEL 20.405(o)(1)(11) 50.36(c)(2) 50.73(a)(2)(vii)
_,0'her (Specify in (10) 9 10 10 20.405(a)(1)(iii) x 50.73(a)(2)(I) 50.73(a)(2)(vill)( A)
Abstract below and 77//HHHHNN/#/H/H Z 20.405(a)(1)(iv) Z 50.73(a)(2)(ii) Z 50.73(a)(2)(vill)(B) in text)
HHHHHHH/HHH//H 20.405(a)(1)(v) 50.73(a)(2)(lii) 50.73(a)(2)(x)
HH/HHHHHHHHHH Uf /H////HH///H///// /
LICENSEE CONTACT FOR THIS LER (12) 1ElEPH04E NUMBER N am 1REA CODE R. W. Kriecer. Station Manager 7!114 3! 6! Bl -! 6! 2! 5! $
COMPLETE ONE LINE FOR EACH CONPONENT FAILURE DESCRIBED IN THis REPORT (13)
USE SYSTEM COMPONENT MANUFAC-
' REPORTABLEH/HH "O
CAUSE
SYSTEM COMPONENT MANUFAC-REPORTABLE TURER TO NPRDS
///////
TURER TO NPRDS
//////
HHH/
/#/H
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SUPPLEMENTAL REPORT EXPECTED (14)
Month Day Year Expected Sutnission l Yes (if yes, complete EXPECTED SUBMIS".10N DATES lbl NO Date (15) g 9
g AbsfRACT (Limit to 1400 spaces, i.e., approximately fifteen single-space typewritten lines) (16)
At approximately 2330 on 6/14/92, with Unit 2 in Mode 1 at 100% power, a plar.t operator identified that Saltwater Cooling (SWC) Pump P112 emergency seal water isolation valve l MUO19 was " closed," rather than "open as required. The valve was opened at 0030 on 6/15/92, restoring the emergency seal water supply to P112. At 0220, a SWC system flow path alignment was performed for both Unita 2 & 3 ?WC pumps to determine if other SWC seal watet valves were similatl.y mis-aligned.
Nu
.her valves were found mis-aligned.
Although the cause and duration of the mis-alignment of MUO19 cannot be definitively determined, SCE has concluded that the mis-alignment most likely occurred during the performance of a quarterly check valve test performed on 5/28/92. This conclusion is based on a review of P112 seal water supply flow data (taken approximately every 2 days) which appears to indicate that MU019 was closed between 5/28/92 and 5/30/92. On
- - 5/28/92, a quarterly check valve test, requiring the repositioning of MUO19, was performed. It is believed that MUO19 was inadvertently left closed following the check valve test due to a procedural deficiency.
Since the mis-alignment may have existed for a period of time in excess af the 72-hour allowed outage time permitted by Technical Specification (TS) 3.7.4,
" Salt Water
- - Cooling System," this event represents a condition prohibited by the TSs.
l-Subsequent investigation identi#ied that the monthly SWC valve alignment survoillance
{ tests did not include the emergency seal water valves for Units 2 and 3.
Inclusion of l these valves in the surveillance is considered 1ppropriate. Corrective actions included: 1) Station Management communicating tmeir expectations to appropriate personnel regarding the rigorous control of plant equipment during testing activities and the rigorous enforcement of equipment status contrc.ls delineated in Operations l Division procedures, 2) modification of appropriate Operations Division surveillance l procedures to include these valves, and 3) a review was performed of all mechanical j safety system TS surveillance requirements to ensure that no similar deficiencies l existed. This event had low safety significance.
9211240056 921119 gDR ADOCK 05000361 PDR
3
.1CENSEE EVENT REPORT (LER) TEXT CONTINUATION
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' SAN ONOFRE NUCLEAR GENERATION STATION DOCTET NUMBER LER NUMBER PAGE UNIT 2 05000361 92-009 2 of-10 Plant: San Onofre Nuclear Generating Station
_l Units: Two and Three' Reactor Vendor: _ Combustion Engineering l-Event Date: June 14, 1992 Time 2330 A.
CONDITIONS AT TIME OF THE EVENT:
l Unit 2 - Mode:
1, Power Operation at 100% Reactor Power l
l Unit 3 - Mode:
1, Power Operation at'100% Reactor Power l
B.
BACKGROUND INFORMATION
1.
Saltwater Cooling (SWC) System l
The SWC system (BS), an engineered safety feature (ESF) (JE] support' system',
provides saltwater from the Pacific Ocean to the component cooling water _(CCW)
(CC) heat exchangers (EX]' for cooling ESF components during normal power generation, normal and emergency shutdawn and cooldown of the reactor, and during design basis accidents. The SWC system for each unit _ consists of two 100% capacity trains.
Each train contains'two-100% capacity pumps (P); one pump is located.in the Unit 2-intake structure and tha uther.is located in the-Unit 3 intake a ructure.
l System design interlocks prevent placing both purps'in a train in-service.
l simultaneously. Manual action is required to place the alternate pump in-service. Specifically, the alternate pump must first be manually aligned and placed in service before it can satisfy the Technical Specification operability z requirements. A single accive failure of any portion of a SWC' system train will not preclude the supply of sufficient cooling water to the other train of, ESFs by the remaining SWC train.
The SWC pump seals (SEAL]- and bearings are normally - cooled and = lubricated by-the service water system (domestic water).
Seal water flow normally ranges
'l from 7 gpm tof15 gpm.
In the' event the service water system becomes-inoperable, (e.g., due to maintensuce or in the unlikely event of a. design basis earthquake (DBE) which_ renders it unavailable), emergency seal water'to the SWC pump is automatically provided. by the SWC_ pump discharge' (rafer to Figure 1).
The emergency seal water supply'is:provided at.a pressure-lower l than that of the service water system, such that loss of service water pressure passively results in the supply.of emergency' seal water to the operating' pump.
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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION SAN ONOFRE NUCLEAR GENERATION STATION DOCKET NUMBER.
LER NUMBER.
PAGE UNIT 2
- - 05000361
'92'-009-01
- - 3'of 10 F 30ti f
. Ql.
Vi _
+
Mug i4 MUO13 Emer gency, Seal Woter m0W IMuols-
- - s MUD 19 P 112 O
Q Lj 0
b-swc M#
_Cf s' er v;ce W
II
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uv;31 iO f x NSR l SR res Nor mal Seal Water Figure 1 - SWC Pump P112 Seal Water System l
2.
Technical Specification (TS) Requirements l
a.
" Salt Water Cooling System," requires that at least two independent SWC loops be Operable in Modes 1-4 The TS Action-specifies
~
that with only one SWC loop Operable, restore at least'two loops to-Operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least Hot Standby-within.the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
l b.
TS 4.7.4, which establiches the SWC system surveillance requirements, j
specifies in paragraph "a" that at least:two SWC loops be-demonstrated l.
operable at least once_per 31 days by. verifying that each valve servicing
~ l safety related equipment that is not locked,Jsealed,or otherwise secured'
_- l in position, is in its-correct position.
l 3.
Station Procedures a.
Station Engineering Procedure SO23-V-3.5.4, " Inservice Testing of _ Check Valves," includes instructions for testing SWC pump bearing emergency.
seal water check valves.
Procedure SO23-V-3.5.4Ltests'tl.e SWC pump'P112 emergency bearing seal water check valve'MUO13 in the "open" direction as follows:
- 1) Operations.is requested by the test engineer to close isolation. valve MUO19 (refer to Figure 1), 2) water. is then verified to.-
be flowing through'normally throttled open valve MUO18 to the floor.
drain, thus verifying that MUO13 has opened, and 3) Operations is requested by the test engineer to re-open MU019.
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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION SAN ONOFRE NUCLEAR GENERATION. STATION DOCKET NUMBER LER NUMBER PAGE UNIT 2 05000361 92-009-01 4 of 10 b.
Operations _ Division Procedure SO123'0-20, "Use of Procedures," provides
- - guidelines for the use of and adherence to procedures.
SO123-0 discusses plant manipulations using procedures which are not within the scope of the Operations Division. -SO123-0-20 specifies that an -
Operations Supervisor (i.e., Senior Reactor Operator) review the l
procedure prior to its use to ensure it requires the manipulation of plant equipment be documented with a sign-off by the individual performing the manipulation, including independent verification-for safety related equipment.
l c.
Surveillance Operating Instruction SO23-3-3.18, " Component l
Cooling / Saltwater System Mcnthly Test," is performed by. Operations l
personnel to satisfy the TS 4.7.4.a surveillance requirements.
l d,
Operating procedure S023-2-8, " Saltwater Cooling System Operation,"
l provides the instructions for SWC system alignment and operation.
4 C.
DESCRIPTION OF THE EVENT:
1.
Event:
At approximately 2330 on June 14, 1992, with Unit 2 in Mode 1 at 100% power, a plant operator (utility, non licensed) identified that SWC Pump P112 emergency seal water isolation valve MUO19 was in the " closed" position, rather than-
"open" as required. The operator identified this discrepancy while. installing a maittenance order tag on an unrelated piece of equipment in the Unit 2 SWC pump room. The valve was opened at 0030 on. June 15, 1992,-thus restoring the emergency sesl water supply to SWC pump P112, At 0220, a SWC system flow path alignment was performed for both Units 2 & 3 SWC pumps to determine if other SWC seal water valves were similarly mis-aligned. No other valves were found mis-aligned.
Although the cause and duration of the mis-alignment of MUO19 cannot be definitively determined, SCE has concluded that the mis-alignment most likely occurred during the performance 1of the MUO13 quarterly check valve test 8
l performed on May 28, 1992. This conclusion is based on a review of SWC P112 seal water supply flow data, which is sensitive to the position of valve MUO19--
'l (as well as to other seal water system valve and parameter changes). TheTflow l.
data' appears to indicate that MUO19 was most likely in the_"open" position when t'm data was taken on May' 28, 1992, and may have been'in the " closed". position on May 30, 1992.
This conclusion is based on a step change increase of 3.5 gpm.
(f rom 10 gpm to 13.5 gpm) in the recorded P112. seal water flow betweenLthe 28th and the 30th.
This. step increase in seal water flow was not regarded by Operations as an anomaly since seal water flow-typically varies from 2-5-gpm
'between SWC pumps and P112 seal water flow remained well within the normal-limits of~7 gpm to 15 gpm.-
In hindsight, this step increase is consistent withi a mispositioning of MUO19-during this time frame.
Since the mis-alignment may have existed for a period of time in excess of the 72-hour allowed outage time permitted by TS 3.7.4, this event is considered to represent a condition prohibited by the TSs.
LICEhSEE EVENT REPORT (LER) TEXT CONTINUATION SAN ONOFRE h"JCLEAR GENERATION STATION DOCKET FJMBER LER NUMBER PAGE UNIT 2 05000363 92-009-01 5_pf 10 l
On July 22, 1992 at 0830, during a review of the TS 4,7.4.a requirements, as a l
follow-up action to the event described above, it was determined that the SWC l
pump emergency seal water supply valves were not included in the monthly valve l
alignment surveillance (i. e., SO23-3-3.18) for Units 2 and 3.
Inclusion of l
these valves in tia surveillance is considered appropriate. Although controls l
were in place to ensure that the valves were properly positioned (i. e., the j
system was properly aligned in accordance with Operating Instruction SO23-2 8),
l the requirement s of TS 4.7.4.a were not fully satisfied due to the exclusion of l
the valves from the monthly surveillance.
2.
Inoperable Structures, Systems or Components that Contributed to the Event:
Not applicable.
3.
Sequence of Events:
p_ alt _g Time Descri u;_i_gn l
5/28/92 SO23-V-3.5.4 quarterly check valve test was performed on MUO13.
This test required closing and then re-opening MUO19.
SWC pump P112 seal water flow readings (taken by Operations approximately every two days) taken prior to the performance of SO23-V-3.5.4 indicates nominal seal water flow of 10 gpm (nominal range is from 7 gpm to 15 gpm) 5/30/92 SWC pump P112 seal water flow reading indicates a step increase of 3.5 gpm (f rom 10 gpm to 13.5 gpm) 6/14/92 2330 Operator identified the mis-alignment of SWC pump P112 emergency seal water isolation valve MUO19.
6/15/92 SWC pump P112 seal water flow res? ng taken prior to re-opening MU019 indicates a seal water flow of 12.5 gpm.
6/15/92 0030 WJ019 was re-opened, thus restoring emergency seal water to P112, 6/15/92 0220 A SWC system flow path alignment was performed for both Units 2 & 3 SWC pumps to detect any additional SWC pump seal water valves out of alignment.
No other valves were found mis-aligned.
6/17/92 SWC pump P112 seal water flow reading indicates a step decrease of 3.7 gpm (f rom 12. 5 gpm to 8. 8 gpm) l 7/22/92 0830 Follow-up review of procedure SO23-3-3.18 revealed that SWC pump emergency seal water valves were not included l
in SO23-3-3.18.
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION
_. r SAN ONOFRE NUCLEAR GENERATION STATION DOCTET NUMBER LER NUMBER-PAGE UNTT 2 05000361 92-009 6~of 10 Date Time Descriotion l
7/22/92 1155 Revised SO23-3-3.18 to_ incl'ude valve positioa
'l verification of the SWC emergency seal water valves.
l 7/22/P2 1615 Completed Unit 2 SWC System valve position l
verification.
l 7/22/92 1620 Complete Unit 3 SWC System valve position u
l verification.
4.
Method of Discovery
l a,
Valve Misalignment:
The mis-alignment of MUO19 was identified by an operator (utility, non-licensed) while installing a maintenance order tag on an unrelated piace of equipment in the Unit 2 SWC pump room.
l-b.
Surveillance Procedure SO23-3-3.18 Deficiency l
The Surveillance Procedure deficiency was found during a review of TS l
e.7.4.a, as a follow-up corrective action to the valve mispositioning l
event. (Performance of this surveillance, with the emergency seal water l
supply valves included, would not have detected the above der ribed l
misalignment until June 18, 1992.)
5.
Personnel Actions and Analysis of Actions:
Not applicable.
6.
Safety System Responses:
l Not_ applicable.
- - I
- - l D.
CAUSE OF THE EVENT
l 1.
Cause-of Valve Misalignment:
Although the cause and duration of the mis-alignment of MUO19 cannot be definitively determined, SCE has concluded. based on cur investigation,.that the l
. valve mis alignment most likely occurred on May 28i 1992 during.the performance s
of MUO13 quarterly check valve test. A thorough investigation of this incident was performed which considered three possible causes; unauthorized manipulation,. inadvertent repositioning of the valve (e.g., accidental bumping which was:not recognized), and possible failure to reclose the: valve after opening it for.an authorized work activity.
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1 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION SAN ONOFRE NUCLEAR GENERATION STATION DOCKET NUMBER LER' NUMBER PAGE UNIT 2 05000361 92-009 01 7 of 10 Intentional, unauthorized manipulation of the valve was not considered likely__
since no other compocents in the area were manipulated and there Pis been no recent history of such activities at SONGS.
Inadvertent repositioning of the valve is considered unlikely since the work activities in the Unit 2 SWC pump room between May 28, 1992 and May 30, 1992 were such that inadvertent contact with MUO19, which is located away from the main passageway, would not be likely and it appeared unlikely that inadvertent manipulation would result in positioning the valve fully closed.
1 The most likely scenario appears to be that the valve.was left in the closed j
position following the check valve test performed on May 28, 1992.
The investigation included reviewing past work activities associated with the Units 2 and 3 SWC pumps, interviewing Operations and Engineering personnel, and' reviewing round sheets in which the local seal water supply flow rates are recorded approximately once every 2 days. A review of Operations round sheets indicate that on May 30, 1992, seal water supply flow was approximately 3.5 gpm above that previously recorded on May 28, 1992.
This increase is consistent with the closure of MUO19, since the portion of the normal saal water flow which is diverted to flush filter F366 and then to the floor drain would be supplied to the pump and would be indicated on the flow u.eter.
Additional seal l
water supply flow data was reviewed to further substantiate this conclusion.
1 l
This information did not change the conclusions provided in Revision 0 of this l
report.
As discussed above, MUO19 was closed on May 28, 1992 for the purpose of testing l
check valve MUO13.
Engineering Procedure SO23-V-3.5.4, used to perform the quarterly check valve test, was signed by the test engineer indicating that he requested Operations to open MUO19. Additionally, the test engineer recalls that MUO19 was opened by the operator as requested. Notwithstanding this, as previously discussed, flow data taken by Operations suggests that MU019 may have been inadvertently left closed folle ing the check valve test.
Operations l
personnel did not recognize that Engineering Procedure SO23-V-3.5.4 did not l
comply with the requirements specified in Operations Procedure SO323-0-20 prior j
to authorizing the test engineer _to perform the check valve test.
Specifically, the requirements for an Operations sign-off and independent verification of a plant manipulation _were not contained in the Engineering procedure.
Therefore, the likely cause of this event is considered to be a procedural deficiency of the Engineering procedure and the improper imolementation of the requirements specified in SO123-0-20.
l 2.
Cause of Surveillance Procedura SO23-3 3.18 Deficiency l
The SWC pump emergency seal water manual isolatica valves were excluded from j
the surveillance procedure due to a misinterpretation of the scope of _ the -
l equipment governed by TS 4.7.4.a.
Previously, only those valves in.the main l
process flow path were considered to be to be governed by TS 4.7.4.a.
Upon j
further review, it has been determined that the safety function of the seal l
water valves is such that the surveillance requirements should be applied to.
l these valves.
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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION
~ k KET NUMBER LER NUMBER PAGE SAN ONOFRE NUCLEAR GENERATION STATION D
UNIT 2 05000361 92-009-01 8 of 10 E4
. CORRECTIVE ACTIONS:
1 Corrective Actions Taketi _
i a.
Once identified, MU019 was re-opened, restoring emergency seal. water-supply to SWC Pump P112 cuch that all of its operability requirements were satisfied, b.
- - Engineering Procedure SO23-V-3.5.4 was enhanced as follows; 1) the check valve testing valve alignment was modified such that it will not be necessary to remove the. emergency seal water supply f rom service (i.e.,
rather than closing MU019, the enhancement requires the closing of the normal seal water supply system isolation valve (MUO31) for the purpose of testing the check valve), 2) a sign-off step was provided for the operator manipulating the valve during the testing, and 3) an' independent verification sign-off step was added to ensure that MUO31 was_re opened following the test.
}
c.
This event was reviewed by appropriate Engineering personnel for lessons learned.
l d.
The Operations Manager has issued a memorandum to all licensed operators conveying management's expectations regarding rigorous enforcement of the equipment status controls dalineated in SO123-0-20.
l e.
Surveillance procedure SO23-3-3.18 was revised and' performed after the l
inclusion of the emergency seal water supply valves.
l f.
A review of all mechanical safety system TS surveillance requirements was l
performed to ensure that no similar deficiencies existed.
2.
Planned Corrective Actions
A review will be performed of appropriate station procedures to ensure that they are in compliance with the requirements specified in Operations Division Procedure SO123-0 20 for the manipulation of plant equipment.
Enhancements will be incorporated as appropriate.
F.
SAFETY SIGNIFICANCE OF THE EVENT:
j' This event is considered to be of low safety significance since p112 remained fully functional during the period in question. The emergency seal water supply would only be -required in the remote event of a loss of service water.
Additionally, Train "B" was available during the majority of time that the emergency seal water was isolated to P112. A probabilistic risk assessment (PRA) was performed indicating that there was a low increase in core damage-f re quency.
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- - LICENSEE EVENT REPORT (LER) TEXT CONTINUATION i
SAN ONOFRE NUCLEAR GENERATION. STATION-DOCKET NUMBER LER NUMBER PAGE UNIT 2 05000361 92-009-01 9 of 10 During the 17-day period in which the emergency seal water supply system was-estimated to have been isolated, the normal seal water supply system continued to provide the flow necessary for proper pump operation, The emergency system was expected to perform ins function only in those remote circumstances in which tP non af ety relcted service water system would have been unavailable, such as an a seismic event.
In all cirewmstances when the normal seal water supply is available, the pump remained iapable of performing its function.
This was the case during the period wron it was postulated that the emergency seal water was isolated.
11, in the unlikely event that the normal seal water supply were to become unavailable, a salt water.cecling pump bearing seal water flow lcw clarm would have u.aunciated in cne control room. An operator would have been dispatched l
locally to the af fected pump to investigate tha low seal water flow.
It io
}
possible that the operator would have recognized that the emergency seal. water l
salve was closed and would hava quickly restored emergency seal water flow to l
the affected pump by opening the valve.
If it was not recognized that the j
emergency seal water valve was closed, or if action was not taken before the l
affected pump suffered damage, action would have Leen initiated to align the l
alternate train pump.
It is estimated that this action would have taken less than one hour.
]
During the period that the emergency seal water supply was postulated to be unavailable, the alternate Train "B"
SWC system remained operable and capable l
of satisfying the plant heat removal requirements except for three occasions (the longest being 45 minutes) required for testing or transferring Train "B'"
pumps. However, during these evolutions, Train "B"
could have been quickly restored in the svent of a loss of SWC pump P112.
Other Train "B"
syntems that experienced brief periods of inoperability include 1) the containment spray system, which underwent pump and valve testing, 2) the fuel handling buildins post accident cleanup unit for associated testing, and 3) the diesel generator for haad-barring prior to a diesel start.
A PRA was performed to determine the increased likelihood of core damage resulting from the inoperability of Train "A" SWC pump P112 during the 17 days between May 28, 1992 and June 14, 1992.
The PRA results indicate an -increase in core damage frequency of approximately BE-7 due to P112 inoperability, The PRA results were not substantially affected by the above Train "B" equipment outages since, in each case, the affected component could have been restored to service in a short period of time.
In conclusion, this event is considered to be of low safety significance since;
- 1) the emergency seal water supply would only be required in the remote event of a loss of service water, 2) Train "B" was available during the majority of time that the emergency seal water was isolated to P112, and 3) there was a low--
increase in core damage frequency as indicated by the ORA.
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LICENSEE EVENT REPORT (LER)- TEXT-CONTINUATION..
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SAN ONOFRE NUCLEAR GETTERATION STATION DOCKET NUtGER LER NUMBER PAGE WIT 2 05000361 92-009-01 10 of'10
~
'O.
ADDITIONAL INFOPJ1ATION:
1.
Component Failure Information
Not applicable.
- - 2.
Previoud LERs for Similar Events:
There.have isot been any previous LERs concerning a mis-alignment of a SWC pump see.1 water-isolation valve as a result of performing check valve testing (which is considered the most likely cause of the event being reported here).
- -, ~.