ML20077R691

Forwards Evaluations & Associated Info Requested in NRC Re Proposed Amend to CNS FSAR Relative to Electrical Breaker Coordination for Incoming Breakers to All Essential 600 Vac MCCs

ML20077R691
Person / Time
Site:	Catawba
Issue date:	12/29/1994
From:	Rehn D DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20077R694	List: ML20077R691 ML20077R710 ML20077R712
References
NUDOCS 9501230081
Download: ML20077R691 (4)

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/ 'r  ; n, l l DukeIbwerCompany ' . D.L aow j , Catawba Nuclear Generation Department %ce President 4800 ConcordRoad . (803)8313205 Omce

. hwk,SC29745 (803)8313426Vax  ;

DUKEPOWER; .

December 29,1994 -

U. S. Nuclear Regulatory Commission

. ATTN: Document Control Desk Washington, D. C. 20555 j

Subject:

Catawba Nuclear Station i 1 Docket Nos. 50-413 and 50-414 Electrical Breaker Coordination FSAR Update Evaluation

Reference:

Ixtter from Robert E. Martin to D. L. Rehn, dated September 14, 1994 Your staff requested in the referenced letter, additional information regarding the proposed ,

amendment to the Catawba FSAR relative to electrical breaker coordination for the incoming 4

breakers to all the essential 600 volt alternating current (VAC) motor-control centers (MCCs) and coordination for all faults for the 125 volt direct-current (VDC) vital instrumentation and control power molded-case breakers in the distribution centers.

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Specifically, the referenced letter requested an appropriate evaluation, pursuant to the provisions  ;

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of 10 CFR 50.59, " Changes, Tests and Experiments", probabilistic risk assessment (PRA) techniques used to quantify the risk of leaving the breakers' uncoordinated and, if practical, a. <

sensitivity analysis showing order-of-magnitude changes in the assumed parameter values used in the PRA that would not invalidat the conclusions of the PRA. -

Additionally, the referenced letter requested information relative to the extent of modifications .

that would be necessary to restore electrical breaker coordination, including the number and type  ;

of breakers and cubicles requiring replacement, information relative to the frequency of cable  :

and MCC failures, and the extent to which cables would need to be redrawn to avoid splices. lI

' Pleas: refer to subsequent attachments for these requested evaluations and associated  !

information.

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U. S. Nuclear Regulatory Commission December 20,1994 Page 2 If there are any additional questions concerning this submittal or the proposed amendment to Catawba's FSAR relative to subject electrical breaker coordination, or if your staff feels that a meeting between appropriate Duke and NRC technical staff would facilitate bringing this issue to closure, please contact Jeff lowery at (803) 831-3414.

Very truly yours, D. L. Rehn, Site Vice-President Catawba Nuclear Station xc: S. D. Ebneter, Regional Administrator, Region II R. E. Martin, ONRR R. J. Freudenberger, Catawba Senior Resident Inspector

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A'ITACHMENTS l

l A, 10 CFR 50.59 for FSAR Change Related to EDSFI Deviation 50-413,414 / 92-01-02 i Relative to IEEE 308-1974 (Attachment 1) 10 CFR 50.59 ATTACllMENTS I

2. Current FSAR Wording

3. Probabilistic Risk Analysis (PRA) for the 125 VDC VitalI & C Power System (EPL) and the 600 VAC Ecsential Auxiliary Power System (EPE)

PRA ATTACIIMENTS

1. NRC letter, dated September 14, 1994, requesting Additional Information on Electrical Breaker Coordination at Catawbn Nuclear Station

2. EPL and EPE Systems Breaker Coordination Memo (previously submitted to NRR)

3. Motor Control Center IEMXG Loads B. Frequency of Cable and Motor Control Center Failures, Extent of Plant Modifications, Number and Type of Breakers and Cubicles Requiring Replacement and Replacement of Cable

8 ArrACInfENT A l

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