TXX-4993, Final Deficiency Rept CP-86-42 Re Class 1E I&C Cabinet Power Supply Breakers.Initially Reported on 860604.Panel Board Circuit Breaker Rating Increased to Ensure Proper Coordination

Final Deficiency Rept CP-86-42 Re Class 1E I&C Cabinet Power Supply Breakers.Initially Reported on 860604.Panel Board Circuit Breaker Rating Increased to Ensure Proper Coordination

ML20209F839
Person / Time
Site:	Comanche Peak
Issue date:	09/02/1986
From:	Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
CP-86-42, TXX-4993, NUDOCS 8609120275
Download: ML20209F839 (1)

Text

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Log # TXX-4993 File # 10110 908.3 TEXAS UTILITIES GENERATING COMPANY NKYWAY TOWER . 400 N(HtTH OLIVE NTREET. L.R. M t . DALLAN. TEXAN 757,0 8 September 2, 1986

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Mr. Eric H. Johnson, Director & ~ 8l986  !

Division of Reactor Safety and Projects b'j l U. S. Nuclear Regulatory Commission _Ld) 611 Ryan Plaza Drive, Suite 1000 L Arlington, TX 76012 -

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET NOS. 50-445 AND 50-446 I&C CABINET POWER SUPPLY BREAKERS SDAR: CP-86-42 (FINAL REPORT)

Dear Mr. Johnson:

On June 4,1986, we verbally notified your Mr. I. Barnes of a deficiency involving Class IE I&C cabinet power supply breakers. This is an interim report of a potentially reportable item under the provisions of 10CFR50.55(e).

We have submitted interim reports logged TXX-4886 and TXX-4945, dated June 27, 1986, and July 30, 1986, respectively.

Various Class lE I&C cabinets had a deficiency where a fault in one DC power supply could cause the common feeder to trip resulting in the loss of both DC l

power supplies. However, the control function would still be maintained through the redundant train B0P or NSSS 7300 analog cabinets. Therefore, this is not a significant deficiency in the final equipment design and there is no breakdown in the QA Prograra. However, the panel board circuit breaker rating l was increased to ensure proper coordination with the power supply circuit breaker. This corrective action did not require any major change in design, extensive evaluation, or significant rework. No adverse conditions exist.

l The issue is not reportable under the provisions of 10CFR50.55(e). Records supporting this determination are available for your inspectors to review at the CPSES site.

Very truly yours,

! 4 W. G. Counsil JCH/amb c - NRC Region IV (0 + 1 copy)

Director, Inspection & Enforcement (15 copies)

U. S. Nuclear Regulatory Commission Washington, D.C. 20555 8609120275 860902 5 DR ADOCK 0500 A invisuos or rexas nmuries us.ecrauc cour.asr  ;

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