ML18100B070

LER 94-007-00:on 940411,infeed Breakers to 4 Kilovolt Vital Buses Tripped on Undervoltage Signal.Caused by Personnel Error.Corrective Action:Involved Technician Counseled Re Identifying components.W/940510 Ltr

ML18100B070
Person / Time
Site:	Salem
Issue date:	05/10/1994
From:	Hagan J, Pastva M Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-94-007-01, LER-94-7-1, NUDOCS 9405170200
Download: ML18100B070 (6)

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• Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038 Salem Generating Station U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Dear Sir:

SALEM GENERATING STATION LICENSE NO. DPR-75 DOCKET NO. 50-311 UNIT NO. 2 LICENSEE EVENT REPORT 94-007-00 May 10, *1994 This Licensee Event Report is being submitted pursuant to the requirements of Code of.Federal Regulation 10CF.R50.73(a)

(2) (iv). Issuance of this report is required within thirty (30) days of event discovery.

MJPJ:pc Distribution 9405170200 940510 PDR ADOCK 05000311 S . PDR Sincerely yours, 95-2189 REV 7-92 NRC FORM 366 .S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 15*92) EXPIRES 5/31 /95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS .. INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LER) COMMENTS .REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF (See reverse for required number of digits/characters for each block) MANAGEMENT AND BUDGET, WASHINGTON, DC 20503. FACILITY NAME (1) DOCKET NUMBER (2) PAGE (3) Salem Generat1ng Station -Unit 2 05000 311 1 OF 04 TITLE(4) ESF Actuation:

Blackout Signal Loading of 2A, 2B, & 2C 4 Kilo.-Volt (4KV) Vital Buses Due To Personnel Error During Emergencv Actuation Instrumentation Funct. Test EVENT DATE (5) LEA-NUMBER (6 REPORT NUMBER (7) OTHER FACILITIES INVOLVED (8) SEQUENTIAL REVISION FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NUMBER MONTH 'DAY YEAR 05000 FACILITY NAME DOCKET NUMBER ----05000 04 11. 94 94 007 00 05 10 94 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check one or more (111 MODE (9) 1 20.402(b) 20.405(c) x 50.73(a)(2)(iv) 73.71(b) POWER

• 20.405(a)(1

)(i) 50.36(c)(1) 50.73 (a) (2) (v) 73.71(c) 11111 20.405(a)

(1) (ii) 50.36(c)(2) 50.73(a)(2)(vii)

OTHER 20.405(a)

(1) (iii) 50.73(a)(2)(i) 50.73(a) (2) (viii) (A) (Specify in Abstract 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) 50. 73(a)(2)(iii) 50.73(a)(2)(x)

LICENSEE CONTACT FOR THIS LER 12) NAME TELEPHONE NUMBER llnclude Area Code) M. J. Pastva .. Jr. -LER Coordinator (609) 339-5165 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) REPORTABLE II SYSTEM COMPONENT MANUFACTURER REPORTABLE CAUSE SYSTEM COMPONENT MANUFACTURER CAUSE TO NPRDS TO NPRDS SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED MONTH DAY YEAR I YES SUBMISSION (If yes, complete EXPECTED SUBMISSION DATE) NO DATE (1S) x ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16) On 4/11/94, at 1035 hours0.012 days <br />0.288 hours <br />0.00171 weeks <br />3.938175e-4 months <br />, the inf eed breakers to the Unit 4 kilo volt Vital Buses tripped on an undervoltage signal resulting in an engineered safety feature automatic starting and "blackout signal loading" of the buses' respective Diesel Generators (DGs) . This occurred during performance of procedure "Emergency Safeguards Actuation System (ESFAS) Instrumentation Monthly", when the ' technician opened an incorrect switch. At 1211 hours0.014 days <br />0.336 hours <br />0.002 weeks <br />4.607855e-4 months <br /> (same day) the Nuclear Regulatory Commission (NRC) was notified of this event, in accordance with lOCFR50. 72 (b) (2) (ii). At approximately 1700 hours0.0197 days <br />0.472 hours <br />0.00281 weeks <br />6.4685e-4 months <br /> (same day), inf eed power to the vital buses was restored and the DGs were secured and returned to standby. This event resulted from a

• perceptual mental processing error. The involved technician has been counseled, reemphasizing the importance of properly identifying components for manipulation and use of the (Stop, Think, Act, and Review) technique.

Appropriate Maintenance Department supervisors and technicians have reviewed this event. The subje_ct procedure will be revised to require concurrent verification of the location (prior to manipulation) of all test-manipulated switches in the SEC cab.inets.

-NRC FORM 366 15-92)

BLOCK NUMBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 REQWRED NUMBER OF DIGITS/CHARACTERS FOR EACH BLOCK NUMBER OF DIGITS/CHARACTERS TITLE UP TO 46 FACILITY NAME 8 TOTAL 3 IN ADDITION TO 05000 DOCKET NUMBER VARIES PAGE NUMBER UP TO 76 TITLE 6 TOTAL 2 PER BLOCK EVENT DATE 7 TOTAL 2 FOR YEAR 3 FOR SEQUENTIAL NUMBER LER NUMBER 2 FOR REVISION NUMBER 6 TOTAL 2 PER BLOCK REPORT DATE UP TO 18 --FACILITY NAME 8 TOTAL --DOCKET NUMBER OTHER FACILITIES INVOLVED 3 IN ADDITION TO 05000 1 OPERATING MODE 3 POWER LEVEL 1 CHECK BOX THAT APPLIES REQUIREMENTS OF 10 CFR UP TO 50 FOR NAME 14 FOR TELEPHONE LICENSEE CONT ACT CAUSE VARIES 2 FOR SYSTEM 4 FOR COMPONENT EACH COMPONENT FAILURE 4 FOR MANUFACTURER NPRDS VARIES 1 CHECK BOX THAT APPLIES SUPPLEMENTAL REPORT EXPECTED 6 TOTAL 2 PER BLOCK EXPECTED SUBMISSION DATE LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 2 DOCKET NUMBER 5000311 PLANT AND SYSTEM IDENTIFICATION:

Westinghouse

-Pressurized Water Reactor LER NUMBER 94-007-00 PAGE* 2 of 4 Energy Industry Identification System (EIIS) codes are identified in the text as {xx} IDENTIFICATION OF OCCURRENCE:

Engineered Safety Feature Actuation; Blackout Signal Loading Of 2A, 2B, And 2C 4 Kilo-Volt (4KV) Vital Buses Due To Personnel Error During Emergency Safeguards Actuation Instrumentation Functional Test Event Date: 4/11/94 Report Date: 5/10/94 This report was initiated by Incident Report No. 9.4-105. CONDITIONS PRIOR TO OCCURRENCE:

Mode 1 Reactor Power 48% -Unit 450 MWe DESCRIPTION OF OCCURRENCE:

• On April 11, 1994, at 1035 hours0.012 days <br />0.288 hours <br />0.00171 weeks <br />3.938175e-4 months <br />, the infeed breakers to the Unit 4KV Vital Buses {EB} tripped on an undervoltage (UV)* signal resulting in an engineered safety feature automatic starting and "blackout signal loading" of the buses respective Diesel Generators (DGs). This occurred during performance of procedure S2.MD-FT.4KV-0001, "Emergency Safeguards Actuation System (ESFAS) Instrumentation Monthly", when the technician mistakenly opened switch 2B2 instead of 2A2, which is specified by the procedure.

At 1211 hours0.014 days <br />0.336 hours <br />0.002 weeks <br />4.607855e-4 months <br /> (same day) the Nuclear Regulatory Commission (NRC) was notified of this event, in accordance with 10CFR50.72(b)

(2) (ii). At approximately 1700 hours0.0197 days <br />0.472 hours <br />0.00281 weeks <br />6.4685e-4 months <br /> (same day), infeed power to the vital buses was restored and the DGs were secured and returned to standby.

• ANALYSIS OF OCCURRENCE:

The Salem safeguards system design basis includes the requirement that the station be safely shutdown during a loss of coolant accident (LOCA) and a coincident loss of offsite power (blackout).

All electrical equipment needed during a LOCA is powered from the vital buses, which can be powered from the standby alternating current diesel generators.

Safeguards Equipment Control (SEC) is a logic system, comprised of three control systems, that provide proper

• ..

EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 2 . DOCKET NUMBER 5000311 LER NUMBER 94-001-00 PAGE 3 of 4 ANALYSIS OF OCCURRENCE: (cont'd) actions in response to any accident and/or blackout condition.

Each SEC (A, B, or C) is physically and electrically isolated from the other, is associated with its own DG and vital bus, and responds to accident (safety injection) and vital bus UV input signals. Based upon the combination of signals, the respective SEC will actuate to strip the vital buses, start the DGs, and reload the vital buses. In accordance with the technician was verifying that relays 27X-2Al, 27X-2A2, and 27X-2A3, each send a 70% UV signal to 2A Vital Bus. This requires successive actuation of the 2Al, 2A2, and 2A3 relays, respectively located in the A, B, and c SEC cabinets.

The technician turned on the test switch for relay 2Al (located in 2A SEC cabinet), and went to 2B SEC cabinet, intending to turn on the test switch for 2A2. Due to a perceptual mental processing error, he mistakenly turned on the test switch for relay 2B2. Due to the preexisting UV signal (per the test) from the 2Al relay, the two out of three logic necessary for "blackout" signal stripping/reloading of the 2B Vital Bus was met and the bus deenergized, as designed.

The same preexisting UV signal from the 2Al relay, in conjunction with the actual UV on 2B Vital Bus, then resulted in meeting the two out of three logic necessary for "blackout" signal stripping/loading of 2A and 2C Vital Buses. APPARENT CAUSE OF OCCURRENCE:

The cause of this event is Appendix B of NUREG-1022.

processing error when the performance of the test. PREVIOUS OCCURRENCES "Persbnnel as in It occurred due to a perceptual mental technician selected the wrong switch during Previous occurrences involving undervoltage conditions on 4KV Vital Buses, which resulted in automatic starting and loading of DGs have been reported *in LERs 311/92-013-00 and 272/93-012-00.

Both occurrences involved personnel error and misoperation of test switches.

Corrective actions to these events disciplinary action with involved individual(s), review of the involved procedure, and review of the event circumstances with applicable Maintenance Department personnel.

SAFETY SIGNIFICANCE This report is reportable pursuant to 10CFR50.73(a)

(2)(iv). This event did not affect the health and safety of the public. Equipment functioned as required during*this event.

• LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Salem Generating Station Unit 2 . CORRECTIVE ACTION: DOCKET NUMBER 5000311 LER NUMBER 94-007-00 PAGE 4 of 4 The involved technician has been counseled.

This included reemphasizing the importance of properly identifying components for manipulation, including use of the "STAR" (Stop, Think, Act, and Review) technique.

• This event has been reviewed with appropriate Maintenance Department supervisors and technicians.

The subject procedure will be revised to require concurrent verification of the location (prior to manipulation) of all switches in the SEC cabinets.

MJPJ:pc SORC Mtg.94-041