ML18085A852

Submits Supplemental Response to IE Bulletin 79-11, Faulty Overcurrent Trip Device in Circuit Breakers for Engineered Safety Sys. Breaker Testing Program Adequately Checks Time Delay Drift & Verifies Delay of safety-related Breaker

ML18085A852
Person / Time
Site:	Salem
Issue date:	12/29/1980
From:	Schneider F Public Service Enterprise Group
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-79-11, NUDOCS 8102200716
Download: ML18085A852 (2)

Text

Frederick W. Schneider Public Service Electric and Gas Company 80 Park Place Newark, N.J. 07101 201/430-7373 Vice President Production December 29, 1980 Mr. Boyce H. Grier, Director Off ice of Inspection and Enforcement U.S. Nuclear Regulatory Commission Region 1

• 631 Park Avenue

• King of Prussia,.PA

• 19406

Dear Mr. Grier:

SUPPLEMENTAL RESPONSE TO NRC IE BULLETIN NO. 79-11 FAULTY OVERCURRENT TRIP DEVICE IN CIRCUIT BREAKERS FOR ENGINEERED SAFETY SYSTEMS SALEM GENERATING STATION UNIT NOS. l AND 2 DOCKET NOS. 50-272 AND 50-311 In our response to Bulletin 79-11 dated July 3, 1979, Item 4 was addressed as having applied to DB-50 and DB-75 breakers. As we do not have any of these breakers performing overcurrent pro-tection for any safety-related systems, we* answered that "no action was required". In Inspection Report 50-272/79-28 the NRC inspector informed us that the intended meaning of Item 4 was to assure that time delay drift was not a problem in any safety-related breaker. The inspector also indicated that no test schedule exists which would verify time delay of safety related breakers. This *supplementary response will serve to describe the Salem Unit's breaker testing program which assures that time delay drift will not.be *a problem and which verifies the time delays of safety related breakers.

At Sa_lem Generating Station Unit No. 2, we have a surveillanc.~

requirement specified by our Technical Specification Section 3/4.8.3 that requires verification of operability of all contain-ment penetration conductor overcurrent protective devices. This surveillance requirement requires*the selection and functional testing of at least 10% of the ninety-eight (_98) circuit breakers listed in Table 3.8-1. Twenty-six (26). of the listed breakers are performing a safety-related function, but all of the breakers are interchangeable and can *be used for a safety-related function.

We feel that by performance of the existing surveillance require-ment, we are testing a significant sample of the types of breakers

. in service that Item: 4 of 79-11 addresses. Fur;thermore, the test

.... **=. '* ...,

Boyce H. Grier, _Dir. 12-29-80 results, both time and current settings, are recorded and are retained in the plant files.

• . As a further consideration, all of the 4kV safety-related breakers for Units l ~nd 2 have their overcurrent protection relay set-tings tested at. normal intervals of 12 months in accordance* with our corporate Relay Test Manual* (in no.case are the intervals longer than 24 months).

We submit that these two procedures provide sufficient data to permit a technically sound judgement to be made concerning set-

. ting stability and mechanism reliability of all our safety-related breakers. If any particular type breaker were to exhibit

• a setting drift beyond the accepted tolerance, _that breaker would be replaced and an enlarged sample of the total number of that type breaker would be* tested to determine the possibility of a generic drift problem. A copy of the relay test results are

• given to the Engineering Department and the Plant Electrical

• Maintenance .Supervisor for their records. The test order sheets may be reviewed at the site.

Approximately sixty-eight (68) manhours were expended on this supplemental bulletin's review.

If you have any further questions, we will be pleased to discuss them with you.

Sincerely, cc U.S. Nuclear Regulatory Commisison Office of Inspection and Enforcement Division of Reactor Operations Inspection Washington, .DC 20555