ML19207B367

Ack Receipt of 790626 Ltr Re Multiple Equipment Failures & Unnecessary Challenges to Reactor Trip & Safeguards Sys. Review of Unit 1 Records Indicates No Such Events Occurred. Will Revise Procedure to Assure Sys Safety

ML19207B367
Person / Time
Site:	North Anna
Issue date:	08/21/1979
From:	Stallings C VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Harold Denton Office of Nuclear Reactor Regulation
References
NUDOCS 7908240506
Download: ML19207B367 (1)

Text

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August 21, 1979 Mr. Harold R. Denton, Director Serial No. 580/062679 Office of Nuclear heactor Regulation PG/DL3:baw Attn: Mr. Darrell G. Eisenhut, Acting Director Docket Nos. 50-338 Division of Operating Reactors 50-339 U. S. Nuclear Regulatory Coranission License Nos. NPF-4 L'ashington, D. C. 20555 CPPR-78

Dear Mr. Denton:

This is in response to your letter of June 26, 1979 regarding multiple equipment failures and unnecessary challenges to the reactor trip and the safeguards systems.

A review of station records has been conducted to detemine if North Anna Unit I has had any events resulting in multiple equipment f ailures similar to the event described in your let.ter. No such events have occurred.

However, there were a few cases where reactor trips were experienced during the performance of periodic nucveillance t< . ting ned where revision of the procedures could reduce the possibility of future, similar challenges to the reactor trip and safeguards systems. The procedures that were being utilized during those events have been, or will be revised to include the appropriate precautions.

A general review of North Anna 1 safety instrumentation surveillance pro-cedures has been conducted. All were found to contain statements indicating the importance of avoiding challenges to the protective features by assuring that only one protection channel is in a trip condition at a time.

Managenent policies and procedures are in strict compliance with the require-ments set forth in the Technical Specifications. If equipment failures were to caase both redundant trains of a safety feature to become inoperable, the unit would be shutdown as required by T.S. 3.0.3. Prior to start-up of the unit, management would review and evaluate equipment failures and such equipment would be restored to an operable status as required by Technical Specificaticns. The purpose of periodic surve.11ance is to discover these i

equipnent problems before they can occur to prevent such equipment failures from reducing the ability of safety systems to function. When the periodic test program is managed successfully and the tests are perfotned as scheduled, the chance of single or multiple equipment failures is greatly reduced.

Very trul y yours ,

y' -

y Q* { t )fdtdo Q>

C. M. Stallings Vice President-Pewer Supply and Production Operations 4

cc: Mr. James P. O'Re illy 'O' 7 9082 4 0 W