ML20148H912

Provides Updated Info Re Impact of Failure of Circulating Water Sys Piping on ESF at Plant

ML20148H912
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	06/09/1997
From:	Duffy J VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BVY-97-80, NUDOCS 9706130132
Download: ML20148H912 (2)

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-V"ERMONT YANKEE IVUCLEAR POWER CORPORATION Ferry Road, Brattleboro, VT 05301-7002 ENGINE R N OFFICE 580 MAIN STREET BoLToN, MA 01740 1

($08) 779-6711 June 9,1997 BVY 97-80 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

References:

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

(b) Letter, VYNPC to AEC, dated November 1,1972

Subject:

Clarification of Circulating Water System Design Information in Reference (b) Vermont Yankee provided information requested by the Atomic Energy Commission (AEC) regarding the impact of a failure of the circulating water system piping on engineered safety features at Vermont Yankee Nuclear Power Station (VYNPS). Vermont Yankee recently identified i

information different from that provided in Reference (b). The purpose of this letter is to provide the updated information.

The discharge piping of the circulating water system is located below the concrete floor of the circulating water pump room in the intake structure at VYNPS. In Reference (b), Vermont Yankee stated that a failure of the bellows in the discharge piping of the circulating water system would result in the return of water to the river which is approximately 20 feet below the floor level. As a result, Vermont Yankee concluded that no engineered safety systems would be degraded due to a flooding condition.

Vermont Yankee recently identified through its corrective action program that failure of the bellows in the circulating water system discharge piping would likely cause flooding of the circulating water pump room. The adjacent service water pump room is protected from flooding in the circulating water pump room by a seismic class I wall and a solid,4-inch thick steel door. The door is normally maintained closed and alarms if left open. Although the door is not watertight, flooding in the circulating water pump room would shut the door more tightly. Vermont Yankee assessed potential leakage from tt.e circulating water pump room into the service water pump room and determined that the drainage capacity of the floor drains and pipe chases in the service water pump room would maintain water level below safety-related equipment. Therefore, consistent with the conclusion of Reference (b), failure of the bellows in the discharge piping of the circulating water system is not expected to adversely impact engineered safety equipment. A more formal evaluation of this issue is Verment Yankee Final Safety Analysis Report or Technical Specifications.

' f planned in accordance with our corrective action program. This clarification has no impact on the

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.c VERMONT YANKEL NUCLEAR POWER CORPORAT13N United States Nuclear Regulatory Commission

' June 9,1997 Page 2 of 2 We trust that this submittal provides sufficient information. However, if additional information or clarification is required, please contact this office.

Sincerely, VERMONT YANKEE NUCLEAR POWER CORPORATION

-fd2 y James J. Duffy Licensing Engineer c: USNRC Region 1 Administrator USNRC Resident inspector -VYNPS USNRC Project Manager - VYNPS i

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