05000272/LER-1982-064, Forwards LER 82-064/03L-0.Detailed Event Analysis Encl

Forwards LER 82-064/03L-0.Detailed Event Analysis Encl

ML20069D935
Person / Time
Site:	Salem
Issue date:	09/08/1982
From:	Midura H Public Service Enterprise Group
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20069D937	List: 05000272/LER-1982-064, Forwards LER 82-064/03L-0.Detailed Event Analysis Encl 05000272/LER-1982-064-03, /03L-0:on 820816,Westinghouse Reported Potential Problem Re Solid State Protection Sys.Evaluation of Rept for Applicability to Facility Underway.Supplemental Rept Will Be Submitted
References
NUDOCS 8209220331
Download: ML20069D935 (4)

LER-1982-064, Forwards LER 82-064/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2721982064R00 - NRC Website

text

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O PSEG Public Service Electric and Gas Company P.O. Box E Hancocks Bridge, New Jersey 08038 Salem Generating Station September 8, 1982 Mr.

R.

C.

Haynes Regional Administrator USNRC Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406

- Dear Mr. Haynes:

LICENSE NO. DPR-70 DOCKET NO. 50-272 REPORTABLE OCCURRENCE 82-064/03L Pursuant to the requirements of Salem Generating Station Unit No. 1, Technical Specifications, Section C.9.1.9.b, we are submitting Licensee Event Report for Reportable Occurrence 82-064/03L.

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

Sincerely yours,

//

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J. Midura General Manager -

Salem Operations RH:ks[Af[

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o Report Number:

82-064/03L Report Date:

09-08-82 Occurrence Date:

08-16-82 Facility:

Salem Generating Station, Units 1 and 2 Public Service Electric & Gas Company Hancocks Bridge, New Jersey 08038 IDENTIFICATION OF OCCURRENCE:

Solid State Protection System --Possible Undetectable Failure.

This report was initiated by Westinghouse Report NS-EPR-2638.

CONDITIONS PRIOR TO OCCURRENCE:

Not Applicable.

DESCRIPTION OF OCCURRENCE:

On August 4, 1982, Westinghouse verbally notified Public Service Electric and Gas (PSE&G) Company of a potential problem associated with the Solid State Protection System (SSPS) in service at Salem Station Units 1 and 2.

During review of a schematic diagram of the SSPS, Westinghouse engineers discovered a potential undetectable failure which could exist in on-line testing circuits for relays in the system.

Westinghouse issued a' report,.!(NS-EPR-2638), on August 16, 1982, on this potential problem.

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

Not Applicable.

ANALYSIS OF OCCURRENCE:

The Solid State Protection System-(SSPS) consists of two redundant systems, Train A and Train B, identical in function, to provide protection for the Nuclear Reactor Systems.

Each Train cabinet has an input relay bay, a logic bay, and an output relay bay.

Each train of the system has two types of protective outputs, one to trip the reactor and one to actuate safeguard systems to protect the plant.

A decision to trip the reactor is based on error signal inputs to the SSPS logic.

If a particular combination of one or more trip conditions exists, the logic system will open the reactor rod control system trip breakers and bypass breakers, causing an automatic control rod trip and a reactor shutdown.

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The safeg,uaYd outputs of the SSPS will operate the valves and motors required to placr/the reactor and plant in a safe shut-down condition.

Master relays in the output cabinet operate slave relays to provide these outputs.

The Westinghouse investigation of the problem, disclosed that periodic testing of the SSPS includes actuation of. master relays which actuate Safeguards, systems.

When a' preselected master relay is energlied, a proving lamp in' series.with the' output (slave) relay coil confirms electrical continuity.

Operation of the relay is prevented by reducing-theJcircuit. voltage from i

120 vac to 15 vdc during testing.. Subsequent tests from.the Safe-

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guards Test Cabinets energize (120'vac) each. output relay to confirm actuation of the Safeauards device.

In those instances where actuation of the final device'cannot be tolerated, a,' proving lamp in the Safeguards test circuits verifies relay contact move-ment, field wiring and electrical continuity through the final device.

The output relay coil continuity is confirmed at the SSPS, without operating the relay, by reducing the-circuit voltage to 15 vde from 120 vac.

Operation of the master relay by means of the pushbutton test switch also removes the shunt from the SSPS proving lamp and allows the 15 vdc to energiae it to confirm the continuity of the output relay coil.

Upon completion of the master relay and output relay coil continuity tests, 120 vac circuit voltage is restored.

However, if the switch contacts which shunt the proving lamp should fail to reclose as expected, 120 vac wduld be applied to the lamp in the event that the system were called upon to operate.

Depending on the output relay coil impedance and the number of output relays being operated by the master relay contacts, the current through the lamp could cause it to burn open before the output relay (s) energized.

In such an instance, associated Safeguards devices in the affected train would not actuate.

Since, during circuit analysis, all identified nondetectable failures mdst be assumed to have occurred, the redun-dant Safeguards actuation' train must be assumed 7to be similarly, 4

if not identically, failed.

'~"Ns Although failure of the subject test switch contacts, ic highly improbabic, Westinghouse has recommended a minor ~ revision to test procedures conducted from the Safeguards Test Cabinets where operation of the SSPS output relays is verified.

The revision will ensure that the relay test circuits in the SSPS operated properly when the systep was returned to its~ normal.

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ANALYSIS OF OCCURRENCE:This occurrence involved the potential of conditions leading to operation in a degraded mode permitted by a limiting condition for operation, or plant shutdown required by a limiting condition for operation, and is reportable in accordance.with Technical Specification 6.9.1.9.b.

CORRECTIVE ACTION

The Westinghouse Report'is currently being evaluated by Nuclear Engineering for applicability to Salem Station.

Because the SSPS in use at Salem uses a different Safeguards Test Cabinet l-than the one supplied'by Westinghouse, the revised procedures will vary somewhat from the Westinghouse recommendations.

A Supplemental Report will be submitted upon completion of the i

evaluation and procedure revisions.

FAILURE DATA:

Not Applicable i

Prepared By R.

Heller bV dM Gendral/ Manager -

Salem Operations SORC Meeting No.

82-82

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