ML18102A710

LER 96-014-00:on 961201,EDG Automatic Start Resulted in ESF Actuation.Caused by Defective anti-pump Relay in 23 Csd Vital Infeed Breaker.Defective anti-pump Relay Identified. W/961227 Ltr

ML18102A710
Person / Time
Site:	Salem
Issue date:	12/27/1996
From:	GARCHOW D F, HASSLER D V Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-96-014-03, LER-96-14-3, LR-N96426, NUDOCS 9701030182
Download: ML18102A710 (4)

Text

{{#Wiki_filter:... *

• Public Service Electric and Gas Company P.O. Box 236 Hancocks Bridge, New Jersey 08038-0236 Nuclear Business Unit DEC 2 7 i996 LR-N96426 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 LER 311/96-014-00 SALEM GENERATING STATION -UNIT 1 FACILITY OPERATING LICENSE NO. DPR-750 DOCKET NO. 50-311 Gentlemen:

This Licensee Event Report entitled "Emergency Diesel Generator Automatic Start -ESF Actuation" is being submitted pursuant to the requirements of the Code of Federal Regulations 10CFR50.73 (a) (2) (iv). Attachment DVH C Distribution LER File 3.7 961227 s R ADOCK 05000311 PDR David F. (£::-;how General Manager Salem Operations 95-2168 REV. 6/94

• NRCFORM388 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 (4-95) EXPIRES 04/30198 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS MANDATORY INFORMATION COl.LECTION REQUEST: 50.0 HRS. LICENSEE EVENT REPORT (LER) REPORTED LESSONS LEARNED ARE INCORPORATED INTO THE LICENSING PROCESS AND FED BACK TO INDUSTRY.

FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION (See reverse for required number of AND RECORDS MANAGEMENT BRANCH REGULATORY COMMISSION, WASHINGTON, DC , AND TO digits/characters for each block) THE PAPERWORK REDUCTION PROJECT OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, 20503. FACILITY NAME (1) DOCKET NUMBER (2) PAGE(3) SALEM GENERATING STATION UNIT 2 05000311 1 of 3 TITLE(4) Emergency Diesel Generator Automatic Start -ESF Actuation EVENT DATE (5) LER NUMBER (8) REPORT DATE (7) OTHER FACILITIES INVOLVED (8) YEAR I FACILITY NAME DOCKET NUMBER MONTH DAY YEAR SEQUENTIAL 'REVISION MONTH DAY YEAR NUMBER NUMBER 12 01 96 96 014 00 12 96 FACILITY NAME DOCKET NUMBER --27 OPERATING N THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check one or more) (11) MODE(9) 20.2201(b) 20.2203(a)(2)(v)

50. 73(a)(2)(i)

50. 73(a)(2)(viii)

POWER 000 20.2203(a)(1) 20.2203(a)(3)(i)

50. 73(a)(2)(ii)

50. 73(a)(2)(x)

LEVEL(10) 20.2203(a)(2)(i) 20.2203(a)(3)(ii)

50. 73(a)(2)(iii) 73.71 lllt1'.'.'.m 1 llll,llllltl1 20.2203(a)(2)(ii) 20.2203(a)(4)

)( 50. 73(a)(2)(iv) OTHER 20.2203(*)(2)(iil) 50.38(c)(1)

50. 73(a)(2)(v) Abelnlct below or C Form 368A 20.2203(a)(2)(iv) 50.38(c)(2)

50. 73(a)(2)(vii)

LICENSEE CONTACT FOR THIS LER (12) NAME TELEPHONE NUMBER (Include Ar .. Code) Dennis v. Hassler, LER Coordinator 609-339-1989 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE I CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE TO NERDS TO NERDS llllllitlll'1 SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED MONTH DAV YEAR IVES XINO SUBMISSION (If yes, complete EXPECTED SUBMISSION DATE). DATE(15) ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16) On December 1, 1996, at 1149 the 2C Emergency Diesel Generator (EDG) started, and accepted load from the 2C 4kV Vital Bus. At the time of the event, a manual transfer from one off-site power supply to another off-site power supply was being performed. The 2C EDG accepted the loads that were aligned to the 2C Vital Bus as designed. The 2C 4kV Vital Bus was de-energized at 1251, and the 2C EDG secured at 1254. Off-site power supply to the 2C 4kV Vital Bus was restored by closing the 24 CSD Vital Inf eed Breaker at 1255. This event was caused by a defective anti-pump relay in the 23 CSD Vital Infeed Breaker. This relay had inadequate clearance between the armature tailpiece and body of the relay. The defective relay was replaced, and the 23 CSD Vital Inf eed Breaker returned to service. This event is reportable in accordance with 10 CFR 73(a) ( 2) (iv) any event or condition that resulted in a manual or automatic actuation of an Engineered Safety Feature (ESF) . NRC FORM 386 (4-95)

• NRC FORM 388A (4-95) U.S.

REGULATORY COMMISSION LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACIUTY NAME (1) DOCKET NUMBER (2) LER NUMBER (8) SALEM GENERATING STATION UNIT 2 96 -014 -00 TEXT (If more apace ia required, use additional copies of NRC Form 388A) (17) PLANT AND SYSTEM IDENTIFICATION Westinghouse -Pressurized Water Reactor Emergency On-site Power Supply System -{EK/-}* PAGE(3) 2 OF 3

• Energy Industry Identification system (EIIS) codes and component functions are identified in the test as {SS/CC} CONDITIONS PRIOR TO OCCURRENCE At the time of identification, Salem Units 1 and 2 were shutdown and defueled.

DESCRIPTION OF OCCURRENCE On December 1, 1996, at 1149 the 2C Emergency Diesel Generator (EDG) {EK/DGO} started, and accepted load from the 2C 4kV Vital Bus {EK/BU}. At the time of the event, a manual transfer from one off-site power supply to another off-site power supply was being performed in accordance with station operating procedures. The 2C 4kV Vital Bus was being supplied from the 24 Station Power Transformer (SPT){EK/XFMR} through Vital Infeed Breaker 24 CSD {BKR}. The procedure directed operators to initiate an automatic transfer to the alternate power supply fed from the 23 SPT, through Vital Infeed Breaker 23 CSD. This step simulates a loss of one off-site power supply and was successfully completed. The procedure then directs the operators to initiate an automatic transfer back to the 24 SPT fed supply, and again, this step was successfully completed. The procedure next requires testing of the manual transfer function. During this step of the procedure, the 2C 4kV Vital Bus was being powered from the 24 SPT, and the licensed operator attempted to manually close the 23 CSD Vital Infeed Breaker from a hand switch {-/HS} in the main control room. The system is designed so that on a close signal the 24 CSD Vital Infeed Breaker will open, and then the 23 CSD will close when 2C Vital Bus Voltage reaches approximately 25 percent of 4160 volts; however, the 23 CSD Vital Infeed Breaker did not close, after the 24 CSD Vital Infeed Breaker opened. The 2C EDG started as designed when the 2C Vital Btis became de-energized. The 2C EDG accepted the loads that were aligned to the 2C Vital Bus as designed. In accordance with station procedures that define the proper response to an EDG start, the 2C 4kV Vital Bus was de-energized at 1251, and the 2C EDG secured at 1254. Off site power supply to the 2C 4kV Vital Bus was restored by closing the 24 CSD Vital Infeed Breaker at 1255. CAUSE OF OCCURRENCE This event was caused by a defective anti-pump relay {-/RLY} in the 23 CSD Vital Infeed breaker. During troubleshooting, the breaker was removed from service and taken to a test stand, where the failure was repeated on the third cycle. NRC FORM 366A (4-95)

• NRC FORM 366A (4-95) U.S. NUCLEAR REGULATORY COMMISSION FACILITY NAME (1) LICENSEE EVENT REPORT (LER) TEXT CONTINUATION DOCKET NUMBER (2) LER NUMBER 8) PAGE(3) SALEM GENERATING STATION UNIT 2 05000311 YEAR I SEQUENTIAL NUMBER REVISION NUMBER 3 OF 3 96 -014 -00 TEXT (If more space is required, use additional copies of NRC Form 388A) (17) CAUSE OF OCCURRENCE (cont'd) The had inadequate clearance between its armature tailpiece and its Bakelite posts, which resulted in the tailpiece being bound against the right post. This lack of clearance caused interference with free operation of the relay, and prevented the normally closed relay contacts from reclosing when the relay de-energized.

PRIOR SIMILAR OCCURRENCES There have been no prior occurrences of a defective anti-pump relay causing an ESF actuation at SAFETY CONSEQUENCES AND IMPLICATIONS There were no safety consequences associated with this event. The Salem accident analysis assumes a loss of off-site power. The failure of the 23 CSD Vital Infeed Breaker to close would not affect the ability of Salem Generating Station to respond to a Design Bases accident. The 2C EDG performed as designed. Further, both the 23 and 24 SPT remained operable, and able to supply power to the 2C Vital Bus by manually closing their respective local breaker. The heal th *_and safety of the public were not affected. CORRECTIVE ACTIONS 1. The defective anti-pump relay was identified. The defective relay was replaced, and the 23 CSD Vital Infeed Breaker returned to service. 2. The relay manufacturer has been notified of the incident.

3. The circuit breaker inspection procedure will be revised to include a step to assure adequate clearance in the anti-pump relay. This will be completed by February 1997. 4. Through a combination of breaker sampling, operating experience reviews, material usage and maintenance history, the most susceptible relays were identified, inspected and found to be operating satisfactorily.

NRC FORM 366A (4-95)}}