ML20100N034
| ML20100N034 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 04/08/1985 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 9872N, NUDOCS 8504180106 | |
| Download: ML20100N034 (2) | |
Text
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Commonwealth Edison oni First N1 tion:t Pina Chicago, Ilknois Address Reply to: Post Othee Box 767 Chicago. tilinois 60690 9
April 8, 1985 Mr Harold R. Denton, Director i
Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Byron Generating Station Units 1 and 2 Technical Specifications NRC Docket Nos. 50-454 and 50-455 References (a): February 20, 1985 letter from T. R.
Tramm to H. R. Denton (b): February 21, 1985 letter from Cecil 0.
Thomas to J. J. Sheppard Dea.- Mr. Denton:
This letter provides confirmation of actions which will be taken in the implementation of revised Techincal Specification requirements for testing of the Byron reactor protection system instrumentation. At the request of the NRC Staff, this letter revises our comitment to the review of analog channel results operational surveillance test results for the purpose of identifying possible common mode failures.
In reference (a), Commonwealth Edison agreed to a one-year review of instruments subject to quarterly analog operational testing for possible common mode failures. Subsequently, the NRC issued in reference (b) their generic SER on WCAP-10271, which contained the technical basis for the requested change in test frequency. After reviewing that SER, we now understand that the NRC's issuance of the revised Technical Specifica-tions mode is conditional upon implementation of a slightly different common mode failure review program. Accordingly, our commitment is therefore being revised.
1 The plant procedure for review of deviation reports will be revised. Completion of deviation reports resulting from quarterly analog channel testing will require an evaluation of the failure to determine if that failure could be a common cause failure. The procedue will require testing of the other channels of like function if the failure is determined to be a plausible common cause failure.
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H. R. Denton 2-April 8,-1985 s
4-For the purposes of this evaluation a common cause failure will be defined as a failure which indicates a systematic ~ deficiency in the design,
. fabrication, testing, or operation of a system which would be likely to result in the simultaneous. failure of redundant systems to fulfill their intended safety function. Instrument drift and power failure to a single
. channel are understood to.be examples -of failures which are not common cause failures.
We'understano that the Westinghouse Owner's Group-subcommittee responsible for WCAP-10271'will be issuing guidance for implementing the Technical Specification changes in accordance with the W C's SER.
Additional revisions of our commitments may be necessary when that guidance is received.
One signed original and fifteen copies of this letter are provided for NRC review.
Very truly yours,
-pfi2 f 4 w _-
T. R. Tramm Nuclear Licensing Administrator 1m 9872N W
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