ML17284A756

LER 98-013-00:on 980805,ESF Actuations Were Noted Due to Deenergization of Vital Electrical Bus SM-8.Caused by Inadequate Direction in Troubleshooting Plan.Will Conduct Training for Engineering Personnel.With 980903 Ltr

ML17284A756
Person / Time
Site:	Columbia
Issue date:	09/03/1998
From:	Bemis P, Pfitzer B WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GO2-98-161, LER-98-013, LER-98-13, NUDOCS 9809150143
Download: ML17284A756 (9)

Text

CATEGORY 1 REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9809150143 DOC.DATE: 98/09/03 NOTARIZED: NO DOCKET FACXL:50-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH. NAME AUTHOR AFFILIATION PFITZER,B. Washington Public Power Supply System BEMIS,P.R. Washington Public Power Supply System RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 98-013-00:on 980805,ESF actuations due'o deenergization of vital electrcial bus SM-8 was noted. Caused by inadecpxate A direction in troubleshooting plan. Reset ESF actuations &,

stabilize plant. With 980903 ltr.

DISTRXBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:

T1TLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ZD CODE/NAME LTTR ENCL PD4-2 PD 1 1 POSLUSNY,C 1 1

'INTERNAL: ACRS 1 1 AEOD/SPD/RAB 2 2 AEOD/SPD/RRAB 1 1 1 1 NRR/DE/ECGB 1 1 1 1 NRR/DE/EMEB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOHB 1 1 NRR/DRCH/HQMB 1 1 NRR/DRPM/PECB 1 1 NRR/DSSA/SPLB 1 1 RES/DET/EIB 1 1 RGN4 FILE 01 1 1 EXTERNAL: L ST LOBBY WARD 1 1 LZTCO BRYCE, J H 1 1 NOAC POORE,W. 1 1 NOAC QUEENER,DS 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRZBUTION LISTS OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOUR ORGANIZATION, CONTACT THE DOCUMENT CONTROL DESK (DCD) ON EXTENSION 415-2083 FULL TEXT CONVERSXON REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 23 ENCL 23

WASHINGTON PUBLIC POWER SUPPLY SYSTEhI PO. Box 968 ~ Richland, 1<<'ashington 99352-0968 September 3, 1998 G02-98-161 Docket No. 50-397 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C, 20555 Gentlemen:

Subject:

NUCLEAR PLANT WNP-2, OPERATING LICENSE NPF-21, LICENSEE EN<AT REPORT NO. 98-013-00 Transmitted herewith is Licensee Event Report No. 98-013-00 for WNP-2. This report is submitted pursuant to 10 CFR 50.73 and discusses the items of reportability, corrective action taken, and action to preclude recurrence.

Should you have any questions or desire additional information regarding this matter, please call me or Mr. Paul Inserra at (509) 377-4147.

Respectfully, PR Bemis Vice President, Nuclear Operations Mail Drop PE23 Enclosure cc: EW Merschoff, NRC RIV NRC Sr. Resident'Inspector, MD927N (2)

DF Kirsch, NRC RIV, WCFO INPO Records Center - Atlanta, GA C Poslusny, Jr., NRR DL Williams, BPA, MD1399 PD Robinson, Winston Ec Strawn 9809i50i43 9S090305000397 PDR ADOCK S PDR

r I

C

LICENSEE EVENT REPORT (LER)

FACILITY NAME (1) DOCKET NUMBER (2) PAGE (3)

~

Washin ton Nuclear Plant - Unit 2 50-397 1OF4 TITLE (4)

En ineered Safet Feature F Actuations Due to Deener ization of Vital Electrical Bus SM-8 EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8)

OAY SEQUENTIAL REV. MoroH OAY FAQUIYNAME NUMBER NUMBER FACEIIYNAME 08 05 98 98 013 00 09 03 98 N/A OPERATING MODE THIS REpoRT Is sUSHITTED pURSUANT To THE REQUIREHENTs OF 10 cFR Si (Check one or more) (11) 20.402(b) 20A05(c) 50.73(a)(2)ov) 73.71(b) 20.405(a)(1)(i) 5036(c)(1) 50.73(a) (2)(v) 73.71(c) 20.405(a)(1) Oi) 5036(c)(2) 50.73(a)(2)(vii) OTHER 20.405(a)(1) (iii) 50 73(a)(2)(i) 50.73(a)(2)(viii)(A) 20A05(a)(1)(iv) 50 73(a)(2)(e) 50.73(a)(2)(viii)(B) 20.405(a)(1)(v) 50 73(a)(2)0II) 50.73(a)(2)(x)

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER ((nc(ude Area Code)

BillPfitzer, Licensing Engineer 509-377-2419 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE avaTKM COMPONENT REPORTABLE CAUSE averox COMPONENT MANUFACTURER REPORTABLE TO EPIX TO EPIX SUPPLEMENTAL REPORT EXPECTED (14 ) EXPECTED MONTH DAY YEAR YES NO corn le(ed EXPECTED SUBMISSION OAT ABSTRACT:

On August 5, 1998 at 1452 hours0.0168 days <br />0.403 hours <br />0.0024 weeks <br />5.52486e-4 months <br />, during troubleshooting activities to determine the cause of apparent emergency diesel generator 2 (EDG-2) voltage regulator problems, vital electrical bus SM-8 and its associated loads were deenergized causing several engineered safety feature (ESF) system isolations and half-isolations to occur. SM-8 was reenergized by Operations approximately 8 minutes after being deenergized. AllESF actuations occurred as designed during the event.

Immediate corrective actions were taken to reset the ESF actuations and stabilize the plant.

The cause of the event has been determined to be inadequate direction in the'troubleshooting plan to respond to anticipated abnormal system responses.

Management has reiterated the need for Engineering personnel to include contingency actions in troubleshooting plans for unexpected conditions which may result from troubleshooting activities. Additionally, training willbe conducted for Engineering personnel concerning the need to address anticipated abnormal conditions in troubleshooting plans.

The safety significance of this event is considered minimal.

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME Ii) DOCKET NUMBER I2) LER NUMBER I6) PAGE I3) s BQVENTIAL REVISIOH NUMBER NMBSR Washington Nuclear Plant - Unit 2 50-397 98 013 2 OF 4 TEXT (If more space Is required, use additional copies of NRC Form 366A) (17)

Even D cri i n On August 4, 1998, while performing the emergency diesel generator 2 (EDG-2)[DG] monthly operability test, EDG-2 reactive load (MVAR) oscillations were observed. The oscillations were anomalous and unexpected, and as a result EDG-2 was shutdown and declared inoperable in accordance with Technical Specification (TS) 3,8.1.B. The subsequent troubleshooting and repair efforts focused first on potential grid voltage variations, then on the components of the EDG-2 voltage regulation system. On August 5, 1998, during one of the troubleshooting tests conducted with EDG-2 paralleled to the electrical grid via transformer PQMR)

TR-S and vital electrical bus [BU] SM-8, MVARoscillations were again observed as EDG-2 was loaded.

Personnel involved in the test allowed EDG-2 to run in this condition in an attempt to record data and determine the cause of the oscillations. After approximately 5 minutes the MVARmeter pegged high, causing high EDG-2 output voltage. In accordance with precautions and limitations of the normal plant operating procedures, Operations personnel attempted to regain control of EDG-2 voltage by manual adjustment of the voltage regulator [RG]. When these efforts proved unsuccessful, Operations personnel began reducing generator load.

At 1452 hours0.0168 days <br />0.403 hours <br />0.0024 weeks <br />5.52486e-4 months <br />, about 18 seconds after the MVARindication pegged high, breaker [BKR] 8-3 tripped and locked out due to actuation of protective overload relays [RLY]. This resulted in immediate tripping of breaker 8-DG2 due to breaker interlock logic, which in turn resulted in the temporary loss of vital bus SM-8 and its associated loads. About 24 seconds after automatic tripping of these breakers Operations personnel mariually tripped EDG-2. Vital electrical bus SM-8 was reenergized by Operations approximately 8 minutes after being deenergized.

As a result of the loss of SM-8 and its associated loads the following ESF actuations occurred:

s Isolation of reactor water clean up (RWCV-V-1)[CE)[V]

• Isolation of radioactive equipment drains from the containment (EDR-V-19)[JM][V]

• Isolation of radioactive floor drains from the containment (FDR-V-3)[JM][V]

s Isolation of reactor recirc sample line (RRC-V-19)[JM][V]

• Isolation of reactor building and containment sampling, due to loss of isolation valve power The failure of the EDG-2 voltage regulator and resultant Technical Specification-required plant shutdown is the subject of Licensee Event Report 98-014.

Immediate Corrective Action All ESF actuations were subsequently reset and the associated systems returned to service during plant recovery efforts.

Problem evaluation requests were initiated for the deenergization of SM-8.

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME I I ) DocKET NDMBER I2) LER NuMBER (6) PAGE I 3)

SEQUENTIAL REVISION NUHBER NNQSA Washington Nuclear Plant - Unit 2 50-397 98 013 3 OF 4 TEXT (If more space is required, use additional copies of NRC Form 366A) (17) u hrEval ti n Subsequent evaluation confirms that all ESF actuations that occurred were in accordance with plant design, and that those actuations which should have resulted from this condition did occur as designed.

e fEvn The Engineering personnel involved in developing the troubleshooting plan did not interpret the procedural guidance for development of troubleshooting plans correctly. Consequently, the troubleshooting plan was deficient in that it relied on the precautions and limitations in the normal operating procedure for EDG-2 to provide direction to testing personnel should unexpected system responses occur.. These precautions and limitations are based on operable equipment with predictable responses, and, as in this case, are not adequate when troubleshooting a faulty system or component with an increased potential for unknown or unexpected system responses. The troubleshooting plan should have included additional guidance for abnormal conditions which could have been anticipated as a result of this testing.

Additionally, a review of the precautions and limitations of the normal operating procedure for the EDGs willbe conducted to determine ifadditional direction is necessary for the abnormal conditions which may be encountered during EDG operation.

Further orrec ive Action Management has reiterated the need for Engineering personnel to include contingency actions in troubleshooting plans for unexpected conditions which may result from troubleshooting activities.

Training will be conducted for Engineering personnel concerning the need'to address anticipated abnormal conditions in troubleshooting plans.

A review of the precautions and limitations of the normal operating procedure for the EDGs will be conducted to if determine additional direction is necessary for the abnormal conditions which may be encountered during EDG operation. Revisions will be made to the procedures ifnecessary.

Procedural guidance for development of troubleshooting plans willbe revised to address the need for contingency actions/plans when unusual conditions can be anticipated during troubleshooting activities.

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME I 1 ) DOCKET NUMBER (2) LER NUMBER I6) PAGE I3)

YEAR SEQUENTIAL AEVIS ION NUMBER NUHBSR Washington Nuclear Plant - Unit 2 50-397 98 013 00 4 OF 4 TEXT (If more space Is required, use additional copies of NRC Form 366A) (17)

A e m nt f afe ns enc All ESF actuations which should have resulted from this event occurre'd in accordance with plant design. All ESF actuations were subsequently reset and the associated systems returned to service during plant recovery efforts. Therefore, the safety significance of this event is considered minimal.

S No previous events have been reported which are attributable to lack of adequate detail in troubleshooting plans.