ML18142A188

Responds to NRC 841116 & 23 Requests for Addl Info Re Generic Ltr 83-28,Items 4.2.1 & 4.2.2.Preventive Maint Procedure for DB-50 Reactor Trip Breakers Patterned After Recommended Maint Activities of Westinghouse 831014 Program

ML18142A188
Person / Time
Site:	Surry, North Anna, 05000000
Issue date:	02/15/1985
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Harold Denton, Thompson H Office of Nuclear Reactor Regulation
References
85-090, 85-90, GL-83-28, NUDOCS 8502250560
Download: ML18142A188 (3)

Text

Wlll.MM L STEWART Nuclear Operations Department Vice President Post Office Box 26666

• ., Nuclear Operations Onefames River Plaza Richmond, Virginia 23261 February 15, 1985 VIRGINIA POWER Mr. Harold.R. Denton, Director Serial No.85-090

• Office of Nuclear Reactor Regulation NO/DWS:acm Attn: Mr. H. L. Thompson, Jr. Director Docket Nos. 50-280 Division of Licensing 50-281 U. S. Nuclear Regulatory Commission 50-338 Washington, D. C. 20555 50-339 License Nos. DPR-32 Gentlemen: DPR-38 NPF-4 NPF-7 VIRGINIA POWER NORTH ANNA UNITS 1 AND 2 SURRY UNITS 1 AND 2 RESPONSE TO GENERIC LETTER 83-28 REQUEST FOR ADDITIONAL INFORMATION ITEM 4.2.1 and 4.2.2 Your letters of November 23, 1984 for North Anna and November 16, 1984 for Surry, requested additional information with regard to Generic Letter 83-28, items 4.2.1 and 4.2.2. This information is provided below:

Item 4.2.1 The preventive maintenance procedure for the DB-50 reactor trip breakers for both Surry 1 and 2 and North Anna 1 and 2 is patterned after the recom-mended maintenance activities of the Westinghouse program of October 14, 1983. Format and content are not identical to the standard program, but are similar and for all practical purposes our procedures provide compara-ble methods *for the activities recommended. Procedural inspection activities of the October 14, 1983 Westinghouse Program are presently per-formed on a six month basis at both North Anna and Surry. The twenty items identifed by the request are performed by our procedures.

Item 4.2.2 Procedures utilized for both North Anna and Surry include instructions for measurement of the undervoltage trip attachment dropout voltage parameter; the trip force parameter; and the breaker response time for undervoltage trip parameter. These test parameters are used to determine acceptable performance of the breaker.

Currently, our procedures do not include the measurement of the breaker insulation resistance, a previously unidentified parameter. Although the October 14, 1983 Westinghouse procedure does not include such a 8502250560 850215

~DR ADDCK 05000280 PDR

VIRGINIA POWER measurement, it is our plan to include this measurement in our procedures.

It is our opinion and one also held by Westinghouse that trending of this parameter can produce misleading results. Changing conditions, which are of little significance such as ambient temperature and humidity fluctu-ation can vary the results and make trending ambiguous. We do, however, plan to keep a record of the test results and review it to assure resist-ance values are maintained within uniform industry standards. Necessary procedural changes are planned for completion by April 1, 1985.

Test parameters are measured by maintenance personnel at each preventive maintenance inspection interval. Administrative control of this testing activity and its results are handled by Periodic Test procedures. Test parameters must be within the acceptance criteria in order for the breaker performance to be satisfactory. Unsatisfactory measurements require cor-rective action.

Completed test results are reviewed and analyzed by the station engineer-ing staff at each inspection interval (currently scheduled six months).

The review and analysis consist of observing and recording specific test results and assuring these results meet the Westinghouse standard proce-dure limits. Measured parameter information obtained from the periodic test is used by engineering personnel to recommend adjustments of the inspection interval or corrective action as appropriate.

Very truly yours,

,~L'\~j-*-~

l) cr1 1 W. L. Stewart

rte , I *,

cc: Dr. J. Nelson Grace Regional Administrator VIRGINIA POWER Region II Mr. M. W. Branch NRC Resident Inspector North Anna Power Station Mr. D. J. Burke NRC Resident Inspector Surry Power Station Mr. Steven A. Varga Chief Operating Reactors Branch No. 1 Division of Licensing Mr. James R. Miller Chief Operating Reactors Branch No. 3 Division of Licensing