05000311/LER-1982-063, Forwards LER 82-063/03L-0.Detailed Event Analysis Encl

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Forwards LER 82-063/03L-0.Detailed Event Analysis Encl
ML20062L538
Person / Time
Site: Salem 
Issue date: 08/04/1982
From: Midura H
Public Service Enterprise Group
To: Haynes R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20062L542 List:
References
NUDOCS 8208190143
Download: ML20062L538 (3)
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LER-1982-063, Forwards LER 82-063/03L-0.Detailed Event Analysis Encl
Event date:
Report date:
3111982063R00 - NRC Website
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text

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eg ) > S E G Public Ser vice Ekstric and Gas Company, P.O. Box E Hancocks Bridge, New Jersey 08038 Salem Generating Station August 4, 1982 Mr.

R. C.

Haynes Regional Administrator USNRC Region 1 631 Park Avenue King of Prussia, Pennsylvania 1940G

Dear Mr. Ilaynes :

LICENSE NO. DPR-75 DOCKET NO. 50-311 REPORTABLE OCCURRENCE 82-063/03L Pursuant to the requirements of Salem Generating Station Unit No.

2, Technical Specifications, Section 6.9.1.9.b, we are submitting Licensee Event Report for Reportable Occurrence 82-063/03L.

This report is required within thirty (30) days of the occurrence.

Sincerely yours, h

H.

J.

Midura General Manager -

Salem Operations RF:ks

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  • Report Number:

82-063/03L Report Date:

08-04-82 Occurrence Date:

07-18-82 Facility:

Salem Generating Station, Unit 2 Public Service Electric & Gas Company Hancocks Bridge, New Jersey 08038 IDENTIFICATION OF OCCURRENCE:

No. 2A Vital Bus - De-energized.

This report was initiated by Incident Report 82-184.

CONDITIONS PRIOR TO OCCURRENCE:

Mode 1 - Rx Power 82% - Unit Load 840 MWe.

DESCRIPTION OF OCCURRENCE:

At 1812 hours0.021 days <br />0.503 hours <br />0.003 weeks <br />6.89466e-4 months <br />, July 18, 1982, during routine operation, 4KV Supply Breaker 21ASD tripped open, de-energizing No. 2A Vital Bus.

The Control Room Operator observed that No. 2A Diesel Generator started without loading, and No. 23 Charging Pump, Nos. 21 and 22 Service Water Pumps, and No. 21 Containment Fan Coil Unit (CFCU) were de-energized.

Letdown flow was isolated as a result of the loss of power to the charging pump; No. 21 Charging Pump was immediately started and letdown was re-established.

Technical Specification Action Statement 3.8.2.1.a was entered retroactive to the loss of No. 2A Vital Bus.

An investigation of the problem showed that No. 2A Safeguards Equipment Control (SEC) cabinet digital display was indicating a Code 24 failure, and would not reset.

No flags were locked in on the tripped breaker.

Breaker 22ASD was closed, re-energizing the bus, and all safety related equipment was returned to operation.

The redundant vital buses and associated equipment were operable throughout the occurrence.

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

The loss of No. 2A Vital Bus was caused by the failure of the card file assembly in No. 2A SEC system.

It is suspected that several integrated circuits in the assembly failed, and generated a spurious actuation signal which tripped Breaker 21ASD, without automatic transfer to the alternate supply.

The integrated circuit failures may be related to noise generated in system control circuitry.

i l

LER 82-063/03L.

ANALYSIS OF OCCURRENCE:

The operability of AC power sources ensures that power will be available to supply-safety related equipment required

- for safe shutdown of the facility and mitigation of accidents considered in the FSAR.

As noted, redundant safety related equipment was operable, and the incident involved no risk to the health or safety of the public.

The occurrence constituted operation in a degraded mode permitted by a limiting condition for operation, and is reportable in accordance with Technical Specification 6.9.1.9.b.

Action Statement 3.8.2.1.a requires:

With less than the above complement of AC busses operable or energized, restore the inoperable busses to operable and energized status within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or be in at least hot standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in cold shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

CORRECTIVE ACTION

As mentioned, Breaker 22ASD was closed, re-energizing No. 2A Vital Bus, and at 1826 hours0.0211 days <br />0.507 hours <br />0.00302 weeks <br />6.94793e-4 months <br />, July 18, 1982, Action Statement 3.8.2.1.a was terminated.

The failed card file assembly was replaced with a new unit, and the SEC System satisfactorily tested.

Design Change Request 2ECl387 has been issued to install noise suppression circuitry in the SEC System; ins,tal-lation will be completed during the next refuelling outage.

A commitment to submit a Supplemental Report upon completion was made in LER 82-019/03L.

FAILURE DATA:

Similar problems with the SEC System have occurred twice since January 1, 1982, and are documented in LER's 82-019/03L and 82-031/03L.

Installation of noise suppression devices in t

l Salem Unit No. 1 SEC System has effectively reduced such problems.

l l

Automation Industries, Inc.

Card File Assembly I

Vitro Dwg. No. 1964-1033 bh N

Prepared By R.

Frahm

/

4 Gene'ral Manager -

Salem Operations SORC Meeting No.

82-73

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