ML20092A809

Confirms That Low-Level SG Water Level Setpoint & Associated Allowable Value Were Selected Based on Statistical Analysis of Errors Associated W/Sg Level Instrumentation Loops & Calibr,In Ref to 911118 Supplemental Application

ML20092A809
Person / Time
Site:	Byron, Braidwood
Issue date:	02/06/1992
From:	Schuster T COMMONWEALTH EDISON CO.
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
TAC-M79082, TAC-M79613, NUDOCS 9202100294
Download: ML20092A809 (2)

Text

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( ) 1400 Opus Place

( C ~7 Down:rs Grove. Illinois 60615

'w February 6,1992 I

Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attn: Document Control Desk

Subject:

Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 Supplement to Application for Amendment to Facility Operating Licenses NPF 37/66 & NPF-72/77 Appendix A, Technical Specifications Tac #M79082 and M79613 NBILDocketNot_50-414L455_anG0 456L457

Reference:

a) November 18,1991 letter from T. Schuster to Dr. T. Murley containing a Supplemental Application for amendment to the Byron /Braidwood Facility Operating Licenses

Dear Dr. Murley:

In Reference (a), pursuant to 10 CFR 50.90, Commonwealth Edison Company (CECO) proposed to amend Appendix A, Technical Specifications of Facility Operating Licenses NPF-37/66 and NPF-72/77 for Byron /Braidwood Stations. The proposed amendment was to revise a por1lon of Technical Specification Tables 2.2-1 and 3.3-4, Reactor Trip System Instrumentation Trip Setpoints and Engineered Safety Features Actuation System Instrumentation Tria Setpoints respectivefy, to reduce the setpoint

.for Low Low Steam Generator Level leactor Trip and Auxillary Feedwater initiation from 40.8% of span to 33.0% of span for the Unit 1 Model D-4 Steam Generators.

This setpoint reduction utilizes existing excess margin present in the 40.8% setpoint.

The purpose of this letter is to confirm that the Low-Low Steam Generator water level setpoint and associated allowable value were selected, based on statistical analysis of the errors associated with the steam generator level Instrumentation loops and their calibration. Further, the statistical analysis methodology was consistent with that outlined in WCAP-12583, " Westinghouse Setpoint Methodology for Protection

Systems" and WCAP-12523, " Bases Document for Westinghouse Setpoint Methodology for Protection Systems." These methods have been previously reviewed and approved by the NRC staff.

Commonwealth Edison is notifying the State of Illinois of this supplement to an apalication for amendment by transmitting a copy of this letter to the designated State l Of<icial. \

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g.. s. .j V- + Dr. Thomas Murley : February 6,1992 ,

To the best of my knowledge and belief the statements contained herein are -

true and correct. In some respects, these statements are not based on my personal 1 knowledge but upon information received from other Commonwealth Edison and contractor employees. Such information has been reviewed in accordance with 3

--Company practice and I believe it to be reliable. -

Please direct any questions you have concerning this matter to this office.

Respectfully, ,

4 T.K. Schuster Nu ar Licensing Administrator ,

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