ML20148E794

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Submits Response to NRC Comments Re Offsite Power Sys Design.Proposed Change to TS Will Be Submitted to NRC by 970930
ML20148E794
Person / Time
Site: Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date: 05/29/1997
From: Reid D
VERMONT YANKEE NUCLEAR POWER CORP.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BVY-97-67, NUDOCS 9706030261
Download: ML20148E794 (2)


Text

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ERMONT YANKEE NUCLEAR POWER CORPORATION i

Ferry Road, Brattleboro, VT 05301-7002

.y ENGINEERING OFFICE 580 MA!N STREET BOLTON, MA 01740 1508)779-6711

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May 29,1997 BW 97-67 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

References:

(a) License No. DPR-28 (Docket No. 50-271)

(b) Letter, USNRC to VYNPC, NVY 97-22, dated February 25,1997 (c) Letter, VYNPC to USNRC, BW 97-40, dated March 26,1997 (d) Letter, USNRC to WNPC, NW 97-50, dated April 17,1997 (e) Letter, VYNPC to USNRC, BW 97-57, dated April 29,1997 (f) Letter, USNRC to VYNPC, NW 97-62, dated May 1,1997 (g) Telecon, VYNPC to USNRC, dated May 23,1997

Subject:

Vermont Yankee Response to NRC Comments Regarding Offsite Power

System Design

in Reference (b) the NRC requested additionalinformation regarding the adequacy of the delayed offsite power circuit at Vermont Yankee Nuclear Power Station (VYNPS) which Vermont Yankee provided in Reference (c). In Reference (d) the NRC responded with additional comments regarding Vermont Yankee's offsite power system design, in particular concerning whether the Vernon Hydroelectric Station may be credited as an alternate AC source if it is also considered a delayed source of offsite power.

In Reference (e) Vermont Yankee concluded that the current licensing basis credits the Tie Line from the adjacent Vemon Hydroelectric station as Vermont Yankee's delayed access offsite power source. Consequently, Vermont Yankee informed the NRC that it would evaluate, by May 25,1997, attematives for achieving compliance with the requirements of the Station Blackout (SBO) Rule (10 CFR 50.63) and that any necessary equipment modifications would be implemented as soon as practicable but not later than restart from the 1998 refueling outage.

In Reference (f) the NRC accepted this schedule. In Reference (g), the NRC and Vermont Yankee agreed that the evaluation of attematives would be completed by May 30,1997.

Vermont Yankee currently plans to implement modifications to the existing Backfeed through the main generator step up transformer to make Backfeed an acceptable delayed source of offsite power without reliance on the Vemon Tie. Analyses will be available to support the capacity, capability and timeliness of the Backfeed. Thereafter, subject to appropriate licensing actions, the Vernon Tie, Vermont Yankee's previously approved Station Blackout AAC source, 4

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.T VERMONT YANKEE Nuct. EAR POWER CORPORATION j

United States Nuclear Regulatory Commission May 29',1997 Page 2 of 2 will no longer be credited as a delayed offsite power source and therefore will be available to meet the requirements of 10 CFR 50.63.

Appropriate FSAR and Technical Specification changes will be completed as part of the design change package. A proposed change to the Vermont Yankee Technical Specifications will be submitted to the NRC by 9/30/97.

We trust this provides sufficient information. However, should you have questions or require additional information, please contact this office.

Sincerely, VERMONT YANKEE NUCt. EAR POWER CORPORATION s

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i Donald A. Reid Vice President, Operations I

c: USNRC Region i Administrator USNRC Project Manager - WNPS USNRC Resident inspector - WNPS