ML19209B982

Responds to 790803 Ltr Re NRC Position on Electrical Protection of Containment Penetrations for Facility.Design for Redundant Protective Device Circuit Is in Progress & Will Be Submitted for Review When Completed

ML19209B982
Person / Time
Site:	North Anna
Issue date:	10/05/1979
From:	Brown S VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Harold Denton Office of Nuclear Reactor Regulation
References
640B-080379, 640B-80379, NUDOCS 7910110351
Download: ML19209B982 (2)

Text

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Vepco _. _ __ _. _ _._

October 5, 1979 Mr. Harold R. Denton, Director Serial No. 6408/080379 Office of Nuclear Reactor Regulation PSE&C/GLP:mac: wang Attn: Mr. O. D. Parr, Chief Light Water Reactors Branch No. 3 Docket No. 50-339 Division of Project Management -

U.S. Nuclear Regulatory Commission Washington, DC 20555

Dear Mr. Denton:

STAFF POSITION ON ELECTRICAL PROTECTION Of CONTAINMENT PENETRATIONS FOR RRTH ANNA POWER STATION, UNIT 2 Your letter dated August 3, 1979, on the above subject references IEEE Standard 317 and Regulatory Guide 1.63 as methods to comply with G.D.C. 50.

The North Anna FSAR states compliance with IEEE 317, 1971. Regulatory Guide 1.63 was first issued in late 1973, long after design and procurement of equipment for the North Anna Units. Also, the implementation date for R.G.

1.63 is for construction permits docketed after December 30, 1977.

Implementing these later requirements will necessitate a major retrofit to the completed Unit 2. The exi. sting primary protective devices have just been thoroughly reviewed and some modifications made to power circuits to assure complete coverage for the full range of potential fault current. With the increased surveillance of the existing devices, this provides a highly reliable protection system for the penetratiens.

Your letter implies that the addition of redundant fault current protective devices is considered to be a backfit requirement. Therefore, we l

will comply with the staff position and the backfit will be completed prior to I startup after the first refueling outage on the North Anna Unit 2.

The design for the redundant protective device circuit is in progress and

! will be submitted for your review when complated.

i i

112? 291 f+\o s\

l, 910110 3St4

_2 Should you require further information, please advise.

Very/truly yours, j'

'I Sam,: C. Irowrr, 'Jr.{$ 0 /L~ -%

Senior.Vice President - Power Station Engineering and Construction /

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