ML20137S363

Corrected Page 1 to Responding to 850614 Commitment to Perform Evaluation of Emergency Diesel Generator Control Logic Circuitry.Ltr Number Changed

ML20137S363
Person / Time
Site:	Fort Saint Vrain
Issue date:	09/13/1985
From:	PUBLIC SERVICE CO. OF COLORADO
To:	Hunter D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
P-85313, TAC-59801, NUDOCS 8509300098
Download: ML20137S363 (2)

Text

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Company of Colorado P.O. Box 840 Denver, CO 80201- 0840 2420 W. 26th Avenue, Suite 1000, Denver, Colorado 80211 (303)S71 7511 September 13, 1985 Fort St. Vrain Unit No. 1 P-85313 Regional Administrator ' ] m @ P fl N 7 [ h i:

Region IV p

U. S. Nuclear Regulatory Comission 611 Ryan Plaza Drive, Suite 1000 L

SFP 2 3 E jj Arlington, Texas 76011 - -

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Attn: Mr. Dorwin R. Hunter Docket No. 50-267

SUBJECT:

Emergency Electrical Power System Independence

REFERENCES:

(1) PSC Letter dated June 14, 1985 Warembourg to Johnson (P-85208)

.(2) NRC Letter dated July 10, 1985 Johnson to Lee (G-85268)

Dear Mr. Hunter:

In a letter dated June 14,1985 (Reference 1), Public Service Company (PSC) provided additional information in response to questions raised in the NRC's review of the Emergency Electrical Power Systen design as described in the FSAR. In addition to the information provided, PSC comitted to perform an evaluation of the Emergency Diesel Generator (EDG) control logic circuitry and to provide the results to the NRC staff. In a letter dated July 10, 1985 (Reference 2), the NRC issued a safety evaluation for continued operation in the interim until any necessary design changes are proposed and to reaffirm PSC's comitment to evaluate the control logic design. This letter .is providing PSC's response to this comitment.

k Fort St. Vrain (FSV) was designed using a combination of principles, /

i.e. redundancy, independence, diversity and single failure. Each of 4 these principles was used and/or combined to achieve a highly g

reliable onsite power system. The FSAR comitments concerning independence, redundancy and single failure criteria as they relate v [0) g\g to FSV's onsite power system cannot be taken to be solely the single .

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Interoffice Memo fiDG-85-0601 O Pubh.c Service" Pub 5c Savice Company of Cokwado DATE

September 19, 1985 l

T0: P Letter Distribution i FROM: Peggy Alcarez SUBJ: P-85318 dated September 13, 1985 Please replace page one of P-85318 dated September 13, 1985 with the i

enclosed P-85313. Text did not change, only the P number.

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Feggy Mtarez k U

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s FORM (B) 85022 4016

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