ML17279A307

LER 87-008-00:on 870429,RHR Sys Primary Containment Outboard Shutdown Cooling Supply Valve RHR-V-8 Automatically Isolated Resulting in Loss of RHR Shutdown Cooling.Caused by Personnel Pressurizing One Side of valve.W/870529 Ltr

ML17279A307
Person / Time
Site:	Columbia
Issue date:	05/29/1987
From:	Arbuckle J, Powers C WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
LER-87-008, NUDOCS 8706100023
Download: ML17279A307 (8)

Text

REQUL TORY INFORMATION DISTRIBUT N S TEM (RIDS)

ACCESSION NBR: 8706100023 DOC. DATE: 87/05/29 NOTARl ED: NO DOCKET ¹ FACIL: 50-397 WPPSS Nuclear Progecti Unit 2> Wash i'ngton Pub li, c Powe 05000397 AUTH. NAME AUTHOR AFFILIATION ARBUCKLE, J. D. Washington Public Power Supply System POWERS. C. M. Washington Public Power Supply SMstem REC IP. NAME RECIPIENT AFFILIATION SUB JECT: LER 87-008-00: on 870429. RHH sos primary containment outboard shutdown cooling supply valve RHR-V-8 automatical lg isolated resulting in loss of RHR shutdown cooling. Caused bg personnel pressurizing one side of valve. W/870529 1 tr.

DISTRIBUTION CODE: IE22D COPIES RFCEIVED: LTR ENCL SIZE:

TITLE: 50. 73 Licensee Event Report (LER)i Incident Rpti etc.

NOTES:

RECIPIENT COPIES RECIPIENT COP IES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 PDS PD 1 1 SAMWORTH, R f INTERNAL: ACRS MICHELSON 1 ACRS MOELLER 2 2 AEOD/DOA f AEOD/DSP/ROAB 2 2 AEOD/DSP/TPAB 1 DEDRO 1 1 NRR/DEST/ADE 0 NRR/DEST/ADS 0

'RR/DEST/CEB 1 1 NRR/DEST/ELB 1 NRR/BEST/I CSB 1 1 NRR/DEST/MEB 1 NRR/DEST/MTB 1 1 NRR/DEST/PSB 1 1 NRR/DEST/RSB 1 1 NRR/DEST/SGB 1 NRR/DLPG/HFB 1 NRR/DLPG/GAB 1 f NRR/DOEA/EAB 1 1 NRR/DREP/R*B 1 1 NRR/DREP/RPB 2 2 MAS/ ILRB 1 f NRR/PMAS/PTSB 1 1 REG FIL 02 1 1 RES DEPY QI 1 1 RGN5 FILE 01 1 EXTERNAL: EQSQ QROH, M 5 5 H ST LOBBY WARD 1 LPDR 1 f NRC PDR 1 1 NSIC HARRIS> J 1 NSIC MAYST G 1 TOTAL NUMBER OF COPIES REQUIRED: LTTR 42 ENCL 40

1, NRC form $ 00 UA. NUCLEAR RKOULATORY COkhd)SSION (003) Af(YIOVKDOMS HO. 3)SOMIOO I

KXfihKS: SlollSS LICENSEE EVENT REPORT HLER)

FACILITY NAME ill DOCKET NUMSER (2)

Washin ton Nuclear Plant - Unit 2 0 5 0 0 0 1 OF "ESI'(dual Heat Removal System Shutdown Cooling Containment Isolation Valve Closure (I lll OTHKh FACILITIKS INVOLVED Nl MONTH EVENT DATE (S)

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On April 29, 1987 at 1227 hours0.0142 days <br />0.341 hours <br />0.00203 weeks <br />4.668735e-4 months <br />, the Residual Heat Removal (RHR) System Primary Containment Outboard Shutdown Cooling Supply Valve (RHR-V-8) automatically isolated, causing the loss of RHR Shutdown Cooling. At the time of the isolation, the plant was in Operational Mode 5 (Refueling) with the reactor head removed, the reactor cavity flooded, and the fuel pool gates removed. The cause of the isolation is attributed to maintenance being performed on an equalizing valve for RHR Differential Pressure Indicating Switch (DPIS) 12A.

The event occurred when a Plant Instrument and Control Technician, in attempting to identify reported leakage on 'the equalizing valve to RHR-DPIS-12A (RHR Shutdown Cooling Supply Leak Detection High Flow Indicator), closed the 0%5 equalizing valve and pressurized one side. As a result, RHR-DPIS-12A sensed a AIOa. differential pressure above its setpoint and, by design, caused RHR-V-8 to (hO OO close.

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07~ The cause of the event has been determined to be incomplete guidance provided A)o by the Plant Maintenance Engineer who prepared'the work instructions for Oa performing maintenance on the equalizing valve.

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There is no safety significance associated with this event. At the time of the Oa: isolation, reactor water level was greater than 22 feet above the reactor tww Q (Xla.m vessel i'lange which provides a 'large heat sink for core coo'ling and adequate time to restore RHR Shutdown Cooling, or initiate an alternate decay heat removal method (an alternate method of Shutdown Cooling was,available needed). In addition, RHR Shutdown Cooling was restored in less than one hour if NRC Form 300

(&43)

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U.d. NUCLEAR REOULATORY COMMISSION NRC Fdrsn SCCA (044 I UCENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OM4 NO. S ISO-014d EXPIRES: 4/Sl/KS FACILITY NAME Ill OOCKKT NUMKKR IS LER NUMKER (4) PAOK (SI

.'et@~ CCOUCNTIAL RCVICION NUll C R NUM CR Washington Nuclear Plant - Unit 2 o s o o o 3 9 7 0 800 2oFO 3 TEXT /4'mad epode /e IdduiNE Ued /II/nnN/ /Y/IC Form SRSA'd/ (ITI Plant Conditions a) Power Level - 0$

b) Plant Node - 5 (Refueling)

Event De~seri tion On April 29, 1987 at 1227 hours0.0142 days <br />0.341 hours <br />0.00203 weeks <br />4.668735e-4 months <br />, the Residual Heat Removal (RHR) System Primary Containment Outboard Shutdown Cooling Supply Valve (RHR-V-8) automatically isolated due to maintenance being performed on an equalizing valve for RHR Differential Pressure Indicating Switch (DPIS) 12A. The RHR Shutdown Cooling Supply Valve is a Nuclear Steam Supply Shutoff System (Containment Isolation) valve. The closing of RHR-V-8 resulted in the loss of a suction path to the RHR Shutdown Cooling Loops (the valve is interlocked to the Shutdown Cooling RHR pumps such that the pumps trip when the valve closes). At the time of the event, the plant was in Operational Mode 5 (Refueling) with the reactor head removed, the reactor cavity flooded, and the fuel pool gates removed. At 1244 hours0.0144 days <br />0.346 hours <br />0.00206 weeks <br />4.73342e-4 months <br /> on April 29, 1987 RHR Shutdown, Cooling was re-established using RHR Loop II II 8

The event occurred when a Plant Instrument and Control Technician, in attempting to identify reported leakage on the equalizing valve to RHR-DPIS-12A (RHR Shutdown Cooling Supply Leak Detection High Flow Indicator),

closed the equalizing valve and pressurized one side. As a result, RHR-DPIS-12A sensed a differential pressure above its setpoint (6.3 psid) and, by design, the RHR Shutdown Cooling Isolation Relay (NS-RLY-K30) de-energized, causing RHR-V-8 to close.

The cause of the event has been determined to be incomplete guidance provided by the=Plant Ilaintenance Engineer who prepared the work instructions for performing maintenance on the equalizing valve. The engineer should have provided a caution statement in the work instructions to alert the technician that an RHR Shutdown Cooling isolation would occur if the equalizing valve was closed and pressurized with RHR-DPIS-12A in service. Plant procedures were not the cause of this event.

Immediate Corrective Action RHR-DPIS-12A was returned to service. RHR-V-8 was re-opened and Plant Operators completed actions to return RHR Shutdown Cooling Loop UBU to service.

NRC SORM dddA

P NRC Folm eeeA

~ 0 US. NUCLEAR REOULATOhY COMMISSION Seel UCENSEE EVENT REPORT (LER) TEXT CONTINUATION AFF ROVED OME NO. SIEO-010f ExFIRES: e1311ee FACIUTY NAME Ill OOCKET NlANER If1 LKR NUMEER Iel ~ AOE (SI TfAR NI>>'fQV't~L NVM II Q>>I VISION A NVM fll (gwine Washington Nuclear Plant - Unit 2 0 6 0 0 0 3 9 7 8 7 0 8 0 OF TEXT N>>FF *nqvke4 ace MAWorelHRC FFFm eeeA'sl l ill Further Corrective Action Plant Maintenance and Technical Engineers who prepare Maintenance Work Requests will be instructed to provide special precautions in those situations where work is performed on systems which are in service.

Operations Shift Managers will be expected to either communicate to craftsmen the scope of the work being approved, or provide recommendations to defeat the trip function in those cases where work is to be performed on out-of-service components in systems that are in service.

This LER will be required reading for all Plant Maintenance Engineers, Plant Technical Engineers, Operations Shift Managers and Instrument and Control Technicians.

Safety Siqnificance There is no safety significance associated with this event. At the time of the event the reactor vessel head was removed and reactor water level was greater than 22 feet above the reactor vessel flange. These conditions provide a large heat sink for core cooling with adequate time to restore RHR Shutdown Cooling or initiate an alternate method of decay heat removal. RHR Shutdown Cooling was restored in less than one hour, and an alternate decay heat removal system was available if needed. Secondary containment, although not necessary during the Plant conditions at this time, was maintained throughout the event.

Reactor core circulation was provided by the Reactor Water Cleanup System and the CRD System was operational. This event caused no threat to the safety of the public or plant personnel.

Similar Events None EIIS Information Text Reference EIIS Reference System Component Reactor Containment Residual Heat Removal Shutdown Cooling Supply Valve BO ISV Residual Heat Removal Shutdown Cooling Supply Valve Relay BO Nuclear Steam Supply Shutoff Valve ISV Control Rod Drive System Reactor Water Cleanu System N IIC F 0 R M 54S A 14I.FT\

WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Box 968, ~ 3000 George Washington Way ~ Richland, Washington 99352 Docket No. 50-397 Hay 29, 1987 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

NUCLEAR PLANT NO. 2 LICENSEE EVENT REPORT NO.87-008

Dear Sir:

Transmitted herewith is Licensee Event Report No.87-008 for WNP-2 Plant.

This report is submitted in response to the report requirements of 10CFR50.73

=

and discusses the item of reportability, corrective action taken, and action taken to preclude recurrence.

This is a follow-up to the verbal notification given at 1302 hours0.0151 days <br />0.362 hours <br />0.00215 weeks <br />4.95411e-4 months <br /> on April 29, 1987.

Very truly ours, C. M, Powers (H/D 927M)

WNP-2 Plant Manager CHP:db

Enclosure:

Licensee Event Report No.87-008 cc: Mr. John B. Martin, NRC - Region V Hr, R. T. Dodds, NRC - Site (M/D 901A)

Mr. W. E. Milbrot, BPA (M/D 399)

INPO Records Center - Atlanta, GA Hs. Dottie Sherman, ANI Hr. D. L. Williams, BPA (M/D 399)

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