ML17289B170

LER 90-017-01:on 900830,HPCS Sys Declared Inoperable Due to Crack in 125 Volt Dc Battery Cell Jar.Caused by Functional Design Deficiency.Plant Mod Being Developed to Change HPCS Battery Racks & encls.W/930212 Ltr

ML17289B170
Person / Time
Site:	Columbia
Issue date:	02/12/1993
From:	John Baker, Fies C WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GO2-93-036, GO2-93-36, LER-90-017, LER-90-17, NUDOCS 9302220312
Download: ML17289B170 (8)

Text

ACCELERA7~D DOCUiVlENT DISTP~BUTION SYSTEM REGULA~ INFORMATION DISTRIBUTIORKYSTEM (RIDS)

ACCESSION NBR:9302220312 DOC.DATE: 93/02/12 NOTARIZED: NO DOCKET FACIL:50-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH. NAME AUTHOR AFFILIATION FIES i C. L. Washington Public Power Supply System BAKER,J.W. Washington Public Power Supply System RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 90-017-01:on 900830,HPCS sys declared inoperable due to crack in 125 Vdc battery cell jar.Caused by functional design deficiency. Plant mod being developed to change HPCS battery racks 6 encls.W/930212 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 CLIFFORD,J 1 1 INTERNAL: ACNW 2 2 ACRS 2 2 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 NRR/DET/EMEB 7E 1 1 NRR/DLPQ/LHFB10 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB8H3 1 1 RRSg/ PLB8D1 1 1 NRR/DST/SRXB 8E 1 1 EG FIL 02 1 1 RES/DSIR/EIB 1 1 RG FILE Ol 1 1 EXTERNAL: EGSG BRYCE,J.H 2 2 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MURPHY,G.A 1 1 NSIC POORE,W. 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALL"RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE} CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DONT NEEDI I

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 31 ENCL 31

ti WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Box 968 ~ 3000 George Washfngton Way ~ Richland, Washington 99352 February 12, 1993 G02-93-036 Docket No. 50-397 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555

SUBJECT:

NUCLEAR PLANT WNP-2, OPERATING LICENSE NPF-21 LICENSEE EVENT REPORT NO. 90-017-01 Transmitted herewith is Licensee Event Report No. 90-017-01 for the WNP-2 Plant. This revised report is submitted in response to the requirements of 10CFR50.73. It provides the results of the root cause analysis and an update of the corrective actions taken, This information was not available for Revision 0 of the LER.

Sincerely, J. W. Baker WNP-2 Plant Manager (Mail Drop 927M)

JWB/CLF/my Enclosure CC: Mr. J. B. Martin, NRC - Region V Mr. R. Barr, NRC Resident Inspector (Mail Drop 901A, 2 Copies)

INPO Records Center - Atlanta, GA Mr. D. L. Williams, BPA (Mail Drop 399) 9302220312 930212 PDR ADOCK 050003'P7 S PDR

LICENSEE EVE REPORT (LER)

~ AGILITY NAME (1) DOCKET NUHB R ( ) PAGE (3)

Washin ton Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 I OF 6 TITLE (,4)

HIGH PRESSURE CORE SPRAY SYSTEM INOPERABILITYAS A RESULT OF 125 VDC BALI'ERY INOPERABILITY EVENT DATE 5) LER NUMBER 6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8)

MONTH DAY YEAR YEAR jl SEQUENTIAL EVI SION MONTH DAY YEAR FACILITY NAHES CKET NUMBERS(S)

';, NUHBER UHBER W. 0 5 0 0 0 0 8 3 0 9 0 9 0 0 I 7 0 1 0 2 I 2 9 3 050 0 0 PERATIHG THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5: (Check one or more of the following) (11)

OOE (9) I ONER LEVEL 20.402(b) 20.405(C) 50.73(a)(2)(iv) 77.71(b) 20.405(a)(1)(i) 50.36(c)(1) X 50.73(a)(2)(v) 73.73(c) 20.405(a)(1)(ii) 50.36(c)(2) 50.73(a)(2)(vii) THER (Specify in Abstract 20.405(a)(1)(iii) X 50.73(a)(2)(i) 50.73(a)(2)(viii)(A) below and in Text, NRC 20.405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(viii)(B) Form 366A) 20.405(a)(1)(v) 0.73(a)(2)(iii) 50.73(a)(2)(x)

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER REA CODE C. L. Fies, Licensing Engineer -

5 0 9 7 7 4 1 4 7 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IH THIS REPORT (13)

CAUSE SYSTEH COMPONENT HAHUFACTURER EPORTABLE ;g '.<<'j CAUSE SYSTEH COMPONENT MANUFACTURER REPORTABLE ), Y 0 NPRDS TO NPRDS E J R Y C 1 7 Yes SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED SUBMISSION MONTH DA'Y YEAR ATE (15)

YES (If es c (etc EXPECTED SUBHISSION DATE) HO tRACT (18)

Three related instances of inoperability of the High Pressure Core Spray System (HPCS) occurred over a twenty day period. On August 30, 1990, at 1234 hours0.0143 days <br />0.343 hours <br />0.00204 weeks <br />4.69537e-4 months <br />, during performance of weekly Technical Specification-required surveillance tests, High Pressure Core Spray System (HPCS) 125 VDC Battery cell number nine was discovered to contain a crack in the cell jar. The HPCS 125 VDC Battery was declared inoperable along with the HPCS System. On September 6, 1990, at 1350 hours0.0156 days <br />0.375 hours <br />0.00223 weeks <br />5.13675e-4 months <br />, while performing the weekly Technical Specification battery checks, an electrical maintenance technician discovered that the HPCS 125 VDC Battery voltage was below the value allowed in Technical Specifications. The HPCS Battery and the HPCS System were declared inoperable. It was discovered that Battery voltage had been 0.75 VDC below the minimum value listed in Technical Specifications since August 31, 1990. On September 17, 1990, at 0957 hours0.0111 days <br />0.266 hours <br />0.00158 weeks <br />3.641385e-4 months <br />, in preparation for the replacement of the cracked battery cell, the HPCS System was declared inoperable, however, the cell was not replaced that day. On September 18, 1990, at 1217 hours0.0141 days <br />0.338 hours <br />0.00201 weeks <br />4.630685e-4 months <br />, again in preparation for the replacement of the cracked battery cell, the HPCS System was declared inoperable. At 1415 hours0.0164 days <br />0.393 hours <br />0.00234 weeks <br />5.384075e-4 months <br /> the HPCS System was declared operable after replacement of battery cell number nine, The root cause of this event was a functional design deficiency. Corrective actions which have been identified consisting of a planned modification to the battery racks and enclosures, required reading of the LER by licensed operators, providing written guidance to operations personnel concerning HPCS reportability and modification of the operator requalification training program to include information concerning HPCS reportability. This event posed no threat to the safety of Plant Personnel or the Public.

LICENSEE EVENT REPORT R)

TEXT CONTINUATION AGILITY RANE (1) DOCKET NUNBER (2) LER NUMBER (8) AGE (3) ear umber ev. No.

Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 0 17 Ol 2 F 6 ITLE (4)

HIGH PRESSURE CORE SPRAY SYSTEM INOPERABILITY AS A RESULT OF 125 VDC BATTERY INOPERABILITY I n n iion Power Level - 100%

Plant Mode - 1 (Power Operation) en De cri ti n On August 30, 1990, at 1234 hours0.0143 days <br />0.343 hours <br />0.00204 weeks <br />4.69537e-4 months <br />, during performance of weekly Technical Specification required surveillance tests, High Pressure Core Spray System (HPCS) 125 VDC Battery cell number nine was discovered to contain a crack in the cell jar. The HPCS 125 VDC Battery was declared inoperable along with the HPCS System and the LCO Action statements required by the WNP-2 Technical Specifications for the Emergency Core Cooling Systems (3.5.1) and Electrical Power Systems D.C. Sources - Operating (3.8.2) were entered. Evaluation was then started to plan a course of action. After review by the oncoming Shift Manager and consultation with the Plant Technical Compliance staff, the event was evaluated as reportable by telephone to the NRC per the requirement of 10CFR50.72(b)(2)(iii) within four hours of event discovery. A telephone call was then made to the NRC Bethesda Operations Center at 1832 hours0.0212 days <br />0.509 hours <br />0.00303 weeks <br />6.97076e-4 months <br />, approximately six hours after event discovery. On August 31, 1990, at 1931 hours0.0223 days <br />0.536 hours <br />0.00319 weeks <br />7.347455e-4 months <br />, HPCS Battery cell number nine was jumpered out of the battery and the Technical Specification Action statements were exited.

On September 6, 1990, at 1350 hours0.0156 days <br />0.375 hours <br />0.00223 weeks <br />5.13675e-4 months <br />, while performing the weekly Technical Specification battery checks, an electrical maintenance technician discovered that the HPCS 125 VDC Battery voltage was below the value allowed in Technical Specifications. The HPCS Battery and the HPCS System were declared inoperable and the Technical Specification LCO Action statements for A.C. Sources - Operating (3.8.1. 1),

and ECCS Systems (3.5. 1) were entered. At 1546 hours0.0179 days <br />0.429 hours <br />0.00256 weeks <br />5.88253e-4 months <br /> another weekly battery check surveillance was completed with the results that battery voltage was found to be within Technical Specification values. It was later discovered that a separate crew of electrical technicians, assigned to battery charging support, had discovered the low voltage condition and corrected it, prior to the check done at 1546 hours0.0179 days <br />0.429 hours <br />0.00256 weeks <br />5.88253e-4 months <br />, by adjusting the HPCS Battery Charger. At 1546 hours0.0179 days <br />0.429 hours <br />0.00256 weeks <br />5.88253e-4 months <br />, the HPCS Battery and the HPCS System were declared operable and the Technical Specification LCO Action statements were exited.

This incident involving inoperability of the HPCS System on September 6, 1990, was not reported by telephone to the NRC Bethesda Operations Center because it was realized that this event was not a new instance of inoperability, but a continuation of the occurrence of August 30, 1990. The discovery was made that the HPCS Battery voltage had been inadvertently reset to 0.75 VDC below the Technical Specification minimum value of 129 VDC on August 31, 1990, during the recovery from jumpering battery cell number nine. Thus, the HPCS Battery, HPCS Diesel Generator, and HPCS System had been continuously inoperable since August 30, 1990. This was, therefore, not a new instance of inoperability, but a continuation of the previous event and, as such, not a new reportable occurrence.

LICENSEE EVENT REPORT R)

TEXT CONTINUATION AGILITY KAHE (1) DOCKET KUHBER (2) LER KUHBER (B) AGE (3) ear umber ev. Ko.

Washington Nuclear Plant - Unit 2 0 0 3 9 7 0 5 0 0 017 1 3 F 6 ITLE (4)

HIGH PRESSURE CORE SPRAY SYSTEM INOPERABILITY AS A RESULT OF 125 VDC BATTERY INOPERABILITY On September 17, 1990, at 0957 hours0.0111 days <br />0.266 hours <br />0.00158 weeks <br />3.641385e-4 months <br />, in preparation for the replacement of the cracked battery cell, the HPCS System was declared inoperable and the Technical Specification LCO Action statements for ECCS Systems (3.5.1.c) and A.C. Sources - Operating (3.8.1.1.c, and 3.8.1.1.d) were entered. At 1003 hours0.0116 days <br />0.279 hours <br />0.00166 weeks <br />3.816415e-4 months <br />, the 4160 VAC HPCS Emergency Power Distribution Bus (SM-4) was deenergized. After further evaluation, however, it was realized that LCO Action Statement 3.8.1.1.d. could not be met. This action statement requires that all systems, subsystems, trains, components, and devices that depend on the remaining operable diesel generators as a source of emergency power also be operable. This requirement could not be met because the A train of the Main Steam Leakage Control System (MSLC-A) was inoperable. At 1152 hours0.0133 days <br />0.32 hours <br />0.0019 weeks <br />4.38336e-4 months <br />, the HPCS System was restored to operability. The NRC Bethesda Operations Center was notified of this event involving HPCS System inoperability at 1022 hours0.0118 days <br />0.284 hours <br />0.00169 weeks <br />3.88871e-4 months <br />.

On September 18, 1990, at 1217 hours0.0141 days <br />0.338 hours <br />0.00201 weeks <br />4.630685e-4 months <br />, in preparation for the replacement of the cracked battery cell, the HPCS System was declared inoperable and the 4160 VAC HPCS Emergency Power Distribution Bus (SM-4) was deenergized. The LCO Action Statements were entered for Electrical Power Systems A.C.

Sources - Operating (3.8.1.1.c and 3.8.1.1.d), Electrical Power Systems D.C. Sources - Operating (3.8.2.1.b), ECCS Systems (3.5.1.c) and Electrical Power Systems Onsite Power Distribution Systems-Operating (3.8.3.1.a,2 and 3.8.3.1.b.2). After completion of the replacement of battery cell number nine, the HPCS System was declared operable at 1415 hours0.0164 days <br />0.393 hours <br />0.00234 weeks <br />5.384075e-4 months <br /> and the applicable LCO Action Statements were exited. This event was reported by telephone to the NRC Bethesda Operations Center at 1417 hours0.0164 days <br />0.394 hours <br />0.00234 weeks <br />5.391685e-4 months <br />.

mm iteCorr i A in During all four instances of HPCS System inoperability, the plant operators acted to appropriately place the plant in the condition specified by the Technical Specifications and to initiate timely action to return the HPCS System to operability.

LICENSEE EVENT REPORT R)

TEXT CONTINUATION AGILITY HAME (1) OOCKET HUMBER (2) LER HUMBER (8) AGE (3) ear Inhere ev. Ho.

Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 0 017 01 4 OF 6 ITLE (4)

HIGH PRESSURE CORE SPRAY SYSTEM INOPERABILITY AS A RESULT OF 125 VDC BATTERY INOPERABILITY F rther Eval i n d rr ive i n A. ~Bglhhli L This LER is written to document this series of events as reportable per the requirements of 10CFR50.73(a)(2)(v) as conditions that alone could have prevented the fulfillment of the safety function of structures or systems that are needed to: (A) Shut down the reactor and maintain it in a safe shutdown condition"; and 10CFR50.73(a)(2)(i)(B), "Any operation or condition prohibited by the Plant's Technical Specifications". The inoperability of the HPCS system is a unique event at WNP-2. Unlike the other Emergency Core Cooling Systems, HPCS system inoperability is reportable even though all requirements of Technical Specification LCO Action Statements are being complied with. The HPCS System is a single train system that performs a safety function (e.g., high pressure injection). Because it is a "single train" Emergency Core Cooling System, a reportable conditions occurs any time it is unable to perform its safety function when it is required to be able to do so by plant conditions.

2. There were no structures, components or systems that were inoperable at the start of this event that contributed to the event.

3. The root cause of this event was a functional design deficiency. The battery holder design used angle iron which resulted in sharp corners that could damage the battery during installation and removal. A second root cause involved ergonomics of the enclosure. It is difficult to remove and install batteries without dropping them on the rack.

B. F her rreci eA i n

1. This LER was made required reading for all SRO Licensed operators and all Shift Technical Advisors (STAs) at WNP-2.

2. Written guidance was provided by the Technical Staff Compliance group to the Operations Department concerning reportability of single train safety systems.

3. The operator requalification training program was modified to specifically address Code of Federal Regulation (10CFR50.72) single train (HPCS) operability reporting requirements and other appropriate regulatory compliance issues on an annual basis.

4. A plant modification is being developed to change the HPCS battery racks and enclosures to decrease the probability of battery damage. This will be completed by July 1995.

LICENSEE EVENT REPORT R)

TFXl CONTINUATION AGILITY NAME (1) OOCKET NUMBER (2) LER NUMBER (8) AGE (3) ear umber ev. No.

Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 0 017 01 5 F 6 ITLE (4)

HIGH PRESSURE CORE SPRAY SYSTEM INOPERABILITY AS A RESULT OF 125 VDC BATTERY INOPERABILITY fe i nifi n There is no safety significance associated with this series of events. During the events, the requirements of the WNP-2 Technical Specifications were met with the single exception of the fact that HPCS Battery voltage was 0.75 volts below the minimum value for seven days. This small voltage difference is not normally able to even be read with installed meters and can only be seen when the weekly battery surveillance is performed using a portable precision meter. This small voltage difference did not represent a loss of any significance of the capability of the HPCS Battery to perform its safety function. The Technical Specification LCO actions for the involved events were correctly applied. They require ensuring the operability of the redundant ECCS Divisions 1 and 2, demonstrating the operability of the remaining Emergency Diesel Generators with periodic starts, and ensuring the operability of the Reactor Core Isolation Cooling system while the HPCS system is inoperable. The actions of the plant operators were prompt and correct to ensure the plant was maintained within the bounds of the Technical Specifications and; therefore, within the bounds of the operational safety analysis. Since no safety significance is associated with this event, it posed no threat to the health and safety of the public or plant personnel.

imil r Even LER 90-04 documents a condition of HPCS System inoperability which occurred as a result of a failed HPCS Diesel Generator speed governor droop switch. Corrective actions consisted of installing a new droop switch.

LER 89-43 documents a condition of HPCS System inoperability which occurred as a result of the HPCS pump minimum flow control valves apparent inability to maintain sufficient flow of water through the pump when system flow was secured. Corrective actions consisted of performing a failure analysis to discover the cause of the low flow problem.

LER 89-030 documents a condition of HPCS System inoperability which occurred as a result of the failure of the Suppression Pool suction valve (HPCS-V-15) to fully open during performance of surveillance testing due to a manufacturing error associated with the motor operator. Corrective actions consisted of verification of operability of all similar design valves, revision of Plant procedures for maintenance and repair of Limitorque motor operators, revision of Plant procedures regarding valves found to be difficult to operate, and notification of Limitorque of a 10CFR21 report.

LER 85-22 documents a condition of HPCS System inoperability which occurred as a result of repair efforts for two HPCS initiation status lamps causing inoperability of the HPCS initiation logic. Corrective actions consisted of notification of all Plant Operators and Maintenance and Technical personnel that elementary drawings should be used for general information purposes only and not for troubleshooting.

LICENSEE EVENT REPORT R)

TEXT CONTINUATION AGILITY MAHE (I) OOCKET NUMBER (2) LER NUMBER (8) AGE (3) ear umber ev. Ko.

Washington Nuclear Plant - Unit 2 0 0 0 3 9 7 0 5 0 1 7 I 6 F 6 ITLE (4)

HIGH PRESSURE CORE SPRAY SYSTEM INOPERABILITY AS A RESULT OF 125 VDC BATTERY INOPERABILITY II Inf rmai n R f ~EII f

~~m ggmm~nen High Pressure Core Spray System (HPCS) BG 125 VDC Battery cell EJ BTRY HPCS Battery BG BTRY Emergency Core Cooling Systems HPCS DG EK DG DO-LS-21 DC LIS DO-TK-3C DC TK HPCS Battery Charger BG BYC SM-4 EA BU MSLC-A System SB HPCS Pump minimum flow control valve BG FCV Suppression pool suction valves NH V