ML18353B266

06/18/1975 Letter Providing Additional Information on Abnormal Occurrences Nos. AO-21-74, AO-6-75 and AO-7-75 Per 05/12/1975 Letter

ML18353B266
Person / Time
Site:	Palisades
Issue date:	06/18/1975
From:	Sewell R Consumers Power Co
To:	James Keppler NRC/RGN-III
References
LER 1974-021-00, LER 1975-006-00, LER 1975-007-00
Download: ML18353B266 (2)

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consumers

• Power company Mr. James G. Keppler Office of Enforcement & Inspection Region III US Nuclear Regulatory Commission Additional Information Glen Ellyn, IL 60137 A0-2l-74, 6-75 & 7-75

Dear Mr. Keppler:

By letter dated May l2, l975, you requested additional infor-mation on Abnormal Occurrences 21-74, 6-75 and 7-75. This letter provides the requested information.

Request l.a A0-2l Failure of Diesel Generator l-l Air Start Motor FSAR Section 8.4.1.2 indicates that "Each engine has two inde-pendent starting control circuits including two air motors, " Describe the cause of the slow start on the single air motor and the corrective actions.

Response

A review of our records shows that the cause of the slow start-ing time was not determined. We have, however, reviewed the starting times since this AO and conclude that the slow start was an isolated occurrence since it has not reoccurred.

Request l.b A0-2l Failure of Diesel Generator 1-1 Air Start Motor The justification for modifying the test procedure to test the diesel starting using both air motors is not clear particularly since this test method identified a relay failure which would not apparently have been otherwise identified. Provide your justification for modifying the test procedure.

• Response The monthly testing procedure for the emergency diesel generator requires testing the starting times using only one of the air motors GS b 3

Mr. James G. Keppler Docket 50*-255, License DPR-20

• 2 June.18, 1975 (each air motor is tested every other month) and thus the type of failure which caused A0-21-74 would be identified. As mentioned in A0-21-74, however, we would not consider failure to start, using only one air motor, as an abnormal occurrence provided an immediate retest using both air motors started the diesel generator satisfactorily.

Request l.c A0-21 Failure of Diesel Generator 1-1 Air Start Motor Discuss the applicability of the failure and corrective action to the other diesel generator.

Response

Each of our diesel generators has twenty-seven of the multi-contact relays identical to the one that failed. Since we have had no similar problems with these relays, we concluded that this failure was an isolated occurrence.

Request 2 A0-6-75 and 7 High Effluent Heat Rate and Temperature The cause was stated "to be associated with plant procedure problems." Corrective action does not indicate procedures will be re-vised. Provide details with respect to corrective action to prevent a recurrence.

Response

The plant procedures for "Circulating Water and Chlorination Systems" have been modified following the subject AO. These modifica-tions, however, are considered an interim solution. As you are aware, we have had very limited experience with the closed cycle cooling system which has recently been installed at the plant and have not removed the cooling towers from service since th.ese occurrences.

As mentioned in the reporting of these abnormal occurrences, we. have initiated a study of the closed cycle cooling* system, We will not, however, be able to conclude the study until we have experienced a number of cooling tower start-ups and shutdowns.

Yours very truly*,

Ralph B. Sewell (Signed)

DAB/ds Ralph B. Sewell Nuclear Licensing Administrator CC: Directorate of Licensing