ML20080R201

Interim Deficiency Rept Re Westinghouse A-200 Motor Control Ctrs.Initially Reported on 830909.All Affected Overload Blocks Identified by Personnel Will Be Replaced W/Properly Calibr Overload Blocks

ML20080R201
Person / Time
Site:	Byron, Braidwood, 05000000
Issue date:	10/06/1983
From:	Swartz E COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10CFR-050.55E, 10CFR-50.55E, 7432N, NUDOCS 8310170411
Download: ML20080R201 (2)

Text

.*- x Commonw=lth Edison 'O

.. O ) one First National Plaza, Chicago. tilinois O 7 Address Reply to: Post Office Box 767

\ j / Chicago, Illinois 60690 October 6, 1983 Mr. James G. Keppler, Regional Administrator

- Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137

Subject:

Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 10 CFR 50.55(e) 30 Day Report Westinghouse A-200 MCCs NRC Docket Nos. 50-454/455 and 50-456/457

Dear Mr. Keppler:

On September 9, 1983, the Commonwealth Edison Company

> Project Engineering Department notified Mr. M. Holzmer of your of fice of a deficiency reportable pursuant to 10 CFR 50.55(e) regarding the Westinghouse A-200 Motor Control Centers at our Byron and Braidwood Stations. For your tracking purposes, this deficiency was assigned Number 83-12 for our Byron Station and Number 83-13 for our Braidwood Station.

This letter fulfills the thirty (30) day reporting requirements of 10 CFR 50.55(e) regarding this matter and is considered to be a final report.

DESCRIPTION OF DEFICIENCY During routine testing of Westinghouse Motor Control Centers (MCCs), it was discovered that some of the starters were tripping outside of the acceptable band specified by Westinghouse. Further investigation determined that some of the i overload blocks were poorly calibrated. The overload blocks are

! calibrated and sealed at the factory. The problem is limited to sizes #0, #1, and #2 starters in the Westinghouse A-200 series MCCs.

$$% \ $

8310170411 8",1006 PDR ADOCK O'sOOO S

, fSc? ? \ N c . . .. - - -

s

~ , .

ANALYSIS OF SAFETY IMPLICATIONS Overload tripping is on an inverse time / current curve. The problem is in the low end of the current curve, meaning that the breaker could possibly trip on a relatively low current after a long period of time. This would not be detected during periodic tests unless the motor was operated long enough for the breaker to trip. During or following an accident, equipment powered by the affected MCCs may fail to complete their intended safety function. Examples of equipment affected by this problem 4 include the cubicle cooler fan motors for the Centrifugal Charging Pumps and the RHR Pumps.

CORRECTIVE ACTION l

All affected overload blocks are currently being identified by station personnel. These overload blocks will be replaced with properly calibrated overload blocks and the deficient ones will be recalibrated by Westinghouse service personnel. The corrective actions will be completed prior to fuel load on all units.

i Please address any questions that you or your staff may have concerning this matter to this office.

Very truly yours E. Douglas Swar Nuclear Licensing Administrator cc: RIII Inspector - Byron i RIII Inspector - Braidwood

! Director of Insp. and Enf.

I U.S. Nuclear Commission

(

Washington, DC 20555 I

7432N l

I r

.-. - . - - - . - _ , . . . , - ... .- - ._.--_._. . . . _ . . , - - , , - - - , - - . . - --.