05000280/LER-1990-012, :on 900909,common Mode Failure Mechanism Due to Marine Growth Identified for Emergency Svc Water Pump

:on 900909,common Mode Failure Mechanism Due to Marine Growth Identified for Emergency Svc Water Pump

ML18153C392
Person / Time
Site:	Surry
Issue date:	10/05/1990
From:	Kansler M VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
90-619, LER-90-012, LER-90-12, NUDOCS 9010190262
Download: ML18153C392 (4)

LER-1990-012, on 900909,common Mode Failure Mechanism Due to Marine Growth Identified for Emergency Svc Water Pump

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(vii), Common Cause Inoperability
2801990012R00 - NRC Website

text

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October 5, 1990 U. S. Nuclear Regulatory Commission Document Control Desk Washington, D. C. 20555 Gentlemen:

Virginia Electric and* Power Company Surry Power Station P. 0. Box 315 Surry, Virginia 23883 Serial No.:

Docket Nos.:

License Nos.:

90-619 50-280 50-281 DPR-32 DPR-37 Pursuant to Surry Power Station Technical Specifications, Virginia Electric and Power Company hereby submits the following Licensee Event Report for Units 1

• and 2.

REPORT NUMBER 90-012-00 This report has been reviewed by the Station Nuclear Safety and Operating Committee and will be reviewed by Corporate Nuclear Safety.

Enclosure cc:

Regional Administrator Suite 2900 101 Marietta Street, NW Atlanta, Georgia 30323 901.0.0!:;;

0~.5000:2:::0 PDC

',)

NRC FORM366 (6-89)

FACILITY NAME (1)

U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)

APPROVED 0MB NO. 3150-0104 EXPIRES: 4/30/92 E

ATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0.104)., OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

Surry Power Station, Units 1_ and 2 I

DOCKET NUMBER (2)

I PAGE (3) 0151010101 2 18 1 0 1 loF 013 TITLE 141 Common Mode Failure Mechanism Due to Marine Growth Identified for ESWPs EVENT DATE (6)

LER NUMBER (6)

REPORT DATE (7)

OTHER FACILITIES INVOLVED (8)

MONTH DAY YEAR YEAR }tt sez~~~~~AL (? ~~~~~~. MONTH DAY YEAR FACILITY NAMES DOCKET NUMBERIS) 01s1010101 I

I ol 9 o I 9 9 o. 9 Io - o I 1 I 2 -

ol o 1 I o o Is 9 Io 0151010101 I

I OPERATING MODE (9)

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LICENSEE CONTACT FOR THIS LER 112)

NAME TELEPHONE NUMBER AREA CODE M. R. Kansler, Station Manager

8. I O 14 31 5 17 1-I 3 tl I 81 4

CAUSE

SYSTEM COMPONENT C

BI I I

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I COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

MANUFAC-TURER I I I

SUPPLEMENTAL REPORT EXPECTED (14)

COMPONENT '

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• MANUFAC, TURER I

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I I I MONTH DAY YEAR n YES (If ye,, campl*t* EXPECTED ~UBMISSION DATEi

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NO EXPECTED SUBMISSION DATE 115)

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I ABSTRACT (Limit ta 1400,,,.ce,, i.e., *ppraxim*toly fiftHn 1ingle-,,,.ce typewritton lin*sl (18)

NRC Form 366 (6-89)

On September 6, 1990 with Unit 1 at 74% power and Unit 2 at 100% power, the Emergency Service Water

Pump, 1-SW-P-lA, was declared inoperable when its flow rate was too low to meet the acceptanc~

criterion of 1-PT-25.3A.

On September 9, 1990 with both units at the same conditions as above, the Emergency Service Water Pump, 1-SW-P-lC, was declared inoperable when its flow rate was too low to meet the acceptance criterion of 1-PT-25.3C.

In both cases, the cause of the problem was determined to be marine growth on the impellers and pump suctions. Following maintenance activities, both pumps passed their performance tests and are back in service.

In accordance with 10CFR50. 73(a)(2)(vii), any event where a single cause or condition that can cause two independent trains or channels to become inoperable in a single system designed to mitigate the consequences of an accident is a reportable event.

• HIICFOIIM..

A IMIII 1,

FACILITY NAMl 111 U.1. NUCLlAll l'IEOULATOIIY COMMISSION LICENSEE EVE-REPORT CLER)

TEXT CONTINUATION DOCKET NUMIEII 121 APPROVED OMI NO. :11M>-0104 IXPIIIU: 4IJQlll2 TED IUADEN PEfl IIEm'ONIE TO COMPLY WTH THIS MATION COLLECTION IIEOUEST: IO.O HAS. FORWAflD CDMMENTI IIEGAflDING IUIIDEN ESTIMATE TD THE IIECOIIOS NtlD flEPORTI MANAGEMENT IIIANCH IP~I. u.a. NUCUAII IIIEGULATOIIY COMMISSION, WASHINGTON, DC 2CHI, AND TO THE PAPE,iw()flllt IIEDUCTION PIIO.lfCT l:11IIO.Q1041, OFPICE OF MANAGEMENT AND IUDGET, WASHINGTON, DC 20!50l.

LIii NUMIIR Ill PAOI 1:11 Surry Power Station, Units 1 and 2 o 1s10101a.121s1 o 910 -o 111 2- 010 012 OF ol3

1. o DESCRIPTION OF THE EVENT On September 6, 1990 with Unit 1 at 74% power and Unit 2 at 100% power, the Emergency Service Water Pump (ESWP) (EIIS-BI,P), 1-SW-P-lA, was declared inoperable due - to a low flow rate of 12,450 gpm.

The acceptance criterion of 1-PT-25.3A is 16,785-17,989 gpm. The next day,

• divers removed hydroids, a marine growth, from the suction of the II A 11 ESWP.

The results of the test later that day were acceptable.

Because of the problems with the 11A 11 ESWP, it was decided to test the 11B" and 11C 11 pumps ahead of their regularly scheduled times.

On September 8, 1990, the 11B" ESWP passed its surveillance test.

On September 9, 1990 with both units at the same conditions as above, the ESWP, 1-SW-P-lC, was declared inoperable due to a low flow rate of 15,249 gpm.

The acceptance criterion of 1-PT-25.3C is 16,435-17,619 gpm.

The "C" ESWP was partially disassembled and the endbell, impeller, and diffuser were cleaned of hydroids and barnacles.

The pump was reassembled and retested on September 13, 1990 with satisfactory results.

In both cases, the cause of the failed performance tests was accumulated marine growth of hydroids and barnacles on the impeller and the suction of the pumps.

After removal of the marine growth, both pumps achieved acceptable results.

According to 10CFR50.73(a)(2)(vii), any event where a single cause or condition that can cause two independent trains or channels to become inoperable in a single system designed to mitigate the consequences of an accident is a reportable event.

The ESWPs provide the source of water to the intake canal during the design basis accident.

2. O

SAFETY CONSEQUENCES AND IMPLICATIONS

NIIC,_ aA C..al The ESWPs provide the source of water *10 the intake canal during the design basis accident.

A review of the design basis calculation for intake canal inventory shows the degraded ESWPs met the minimum flow rate required to meet the design basis criteria.

The review shows that a flow rate of 25,350 gpm from two ESWPs will provide adequate inventory to remain within the parameters of* the design basis assumptions.

The total flow rate provided by the "A 11 and "C" ESWP during the performance tests was 27,699 gpm.

In addition, since

• +

NIICfOIIM..

A fM81 FACILITY NAME _CU U.1. NUCUAII IIEGUUTOIIY COMMISSION LICENSEE EVEh.EPORT (LERI TEXT CONTINUATION DOCKET NUMIEII 121

"""OVEO OMI NO. :uao,0104 IXPIIIU:~

EO IUIIDEN,Ell IIUl'ONSE TO COWL Y WTH THIS ATION COLLECTION IIEOUEST: IO.O HRI. fORWAl'ID mllMENTI IIEGMDING IUIIDEI\\I HTIMATE TO THE l'IECOl'IDS AND IIE,ORTI MANAGEMENT IIIANCH IP-6301. U.I. NUCLl!NI IIEGULATOIIY COMMISSION. WAIHINGTON, DC 2CJIM. AND TO

'INE,A,EIIWOflK l'IEOUCTION NIO.ll!CT 131!50410tl. OFPICE OF MANAGEMENT AND IUDGET. WASHINGTON. DC 2QI03, LIii NUMalll Ill

SE QUINT I AL ::~::::: lflEV8ION NUMe[II

.:::::::::.. u.. *111

,~011'1 Surry Power Station, Units 1 and 2 o Is I o I o I o I 21 s Io 9 Io - o I 1 I 2 o lo o I 3 oF o 13 ffXT r* _,,,_ * ~

MldlrlotW NltC fonn -..*a11171 IIIIC *- INA Cl,GI the "B" ESWP had passed its performance test on September 8, 1990 and was fully -operable, adequate cooling water would have been provided by any two of the ESWPs if a design.basis accident had occurred even with the degraded conditions of the "A" and "C" pumps.

This condition did not adversely affect the plants design basis.

Therefore, the health

• and safety of the public was not affected.

3. O

CAUSE OF THE EVENT

The degraded condition of the "A" and "C" ESWP was the result of accumulated marine growth of hydroids and barnacles.

This marine growth increased the flow resistance and mechanical friction within the pumps reducing the pumps' flow rate.

The pumps degraded. to the point where they could not meet the acceptance. criterfa of the required performance tests.

4. O IMMEDIATE CORRECTIVE ACTION<S}

5.0 6.0 7.0 The "B" and "C" ESWPs were surveillance tested ahead of their regularly scheduled times.

The marine growth was removed from the suction of the "A" ESWP by divers.

The "C" ESWP was partially disassembled and internally cleaned* of hydroids and barnacles.

Both pumps passed the subsequent tests.

ADDITIONAL CORRECTIVE ACTION<S}

The "B" ESWP suction was cleaned of hydroids by divers on September 20,- 1990.

ACTIONS TO PREVENT RECURRENCE An engineering evaluation is under* way to

• find a long term solution to this problem.

In the interim, the pump. testing frequency wiH be increased to once a month to more closely monitor pump perfm:mance.

Appropriate actions will be taken based oil the results of the evaluation.

SI?4ILAR EVENTS None.

8. O -MANUFACTURER/MODEL NUMBER NIA