ML20207P220

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Responds to Request for Addl Info Re 861017 Application for Amends to Licenses DPR-53 & DPR-69.Vendor Recommendation Re Purge Valve Svc Life,Coupled W/Util Operational Experience, Justifies Extending Seal Replacement Interval to 4 Yrs
ML20207P220
Person / Time
Site: Calvert Cliffs  Constellation icon.png
Issue date: 01/12/1987
From: Salyards L
BALTIMORE GAS & ELECTRIC CO.
To:
NRC OFFICE OF ADMINISTRATION (ADM)
References
NUDOCS 8701150252
Download: ML20207P220 (2)


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.. 'o BALTIMORE GAS AND ELECTRIC CHARLES CENTER . P.O. BOX 1475 BALTIMORE. MARYLAND 21203 NUCLEAR ENGINEERING SERVICES DEPARTMENT CALVERT CUFFS NUCLEAR POWER PLANT LUS8Y, MARYLAND 20657 January 12,1987 U. S. Nuclear Regulatory Commission Washington, D. C. 20555 ATTENTION: Document Control Desk

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Request for Amendment, Additional Information

REFERENCE:

(a) Letter from Mr. J. A. Tiernan (BG&E), to Mc. A. C. Thadani (NRC),

dated October 17, 1986, Request for A,mendment Gentlemen:

Reference (a), Change No. 2d, addressed the fact that the interval between purge valve seal replacements will be lengthened by approximately one year as a result of our change in refueling cycle length from 13 months to 24 months. This letter provides additional information in response to a verbal request by Mr. S. A. McNeil, NRC Project Manager.

A conference call between BG&E and the purge valve vendor was conducted to discuss the expected purge valve seal service life. The vendor stated that the elastomer manufacturer recommends a five year service life. We also discussed our present maintenance actions, along with maintenance plans coinciding with our future 24-month
fuel cycle, with the vendor. (Normally, one supply and one exhaust valve has its seal l replaced each outage, while the alternate valves are inspected and lubricated.) The l vendor recommended continuing our current seal inspection / replacement program, stating that replacing the seat material every other outage should still provide satisfactory valve service / reliability.

, Our operational experience with the purge valve seat material has been, in general, excellent. The seal still appears new when replaced at the end of three years (the current Technical Specification requirement). Additionally, recent local leak rate testing data was reviewed for both the containment purge inlet and outlet penetrations.

l The majority of the data is well below our administrative leakage limit for each penetration (and our administrative limit is approximately one-sixth of our maximum specified limit). Also, Surveillance Requirement 4.6.4.1.4 requires that containment i 0701150252 G70112 PDR ADOCK 05000317 P PDR

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o- *J Mr. Ashok C. Thadani January 12,1987 Page 2 purge isolation valve leakage rates be performed on a more frequent interval than just once per refueling interval. This Surveillance Requirement also requires leakage rates to be compared to the previously measured leakage rates in order to detect excessive valve degradation.

In summary, the vendor's recommendation concerning purge valve service life, coupled with our operational experience, justifies extending the seal replacement interval to approximately four years. Should you have further questions regarding this reply, we will be pleased to discuss them with you.

Very truly yours, fd o

L. E. Salyards Principal Engineer Licensing and Operational Safety LES/BEH/ dim cc: D. A. Brune, Esquire

3. E. Silberg, Esquire S. A. McNeil, NRC T. Foley, NRC T. Magette, DNR A. C. Thadant, NRC T. E. Murley, NRC