BVY-94-126, Provides Updated Schedule for Completion of Planned Physical Mod of SWS at Plant to Mitigate Potential for Waterhammer Event During Postulated SBO Scenario

Provides Updated Schedule for Completion of Planned Physical Mod of SWS at Plant to Mitigate Potential for Waterhammer Event During Postulated SBO Scenario

ML20078Q397
Person / Time
Site:	Vermont Yankee
Issue date:	12/15/1994
From:	Pelletier J VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BVY-94-126, NUDOCS 9412220150
Download: ML20078Q397 (2)

Text

~ , . . , . = . - -.

I V's a ,

YERMONT YANKEE l

NUCLEAR POWER CORPORATION

. 1

. Ferry Road, Brattleboro, VT 05301-7002 .

ENGINEERING OFFICE  !

580 MAIN STREET -

3

• BOLTON, MA 01740 (508) 779 6711 December 15,1994 BVY 94-126 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 USNRC, BVY 94-57, dated May 20,1994 (c) Letter, USNRC to VYNPC, NVY 94-85, dated June 1,1994 (d) Letter, USNRC to VYNPC, NVY 94-96, dated June 30,1994  ;

Subject:

Vermont Yankee Compilance With the Station Blackout Rule,10CFR50.63 The purpose of this letter is to provide an updated schedule for completion of a planned

physical modification of the Service Water System at Vermont Yankee to mitigate the potential for a waterhammer event during a postulated Station Blackout (SBO) scenario.

In a meeting at Region I office on March 30,1994, and in Reference (b), Vermont Yankee informed NRC of the results of an evaluation performed as part of our Service Water System Self-Assessment effort which concluded that the potential for a waterhammer in the Service Water System upon pump restart during an SBO scenario did exist. As a result, Vermont Yankee implemented procedural controls for operators to preclude the occurrence of a waterhammer during an SBO scenario. These controls were implemented in advance of the SBO compliance date for Vermont Yankee of September 10,1994, and remain in effect.

Vermont Yankee's use of procedural controls was found acceptable by the NRC Staff, as documented in the SBO Supplemental Safety Evaluation Report [ Reference (c)].

In Reference (b) and in a meeting at NRC/NRR on June 16,1994, the summary of which is documented in Reference (d), Vermont Yankee stated that procedural controls for operators would remain in effect until a physical modification of the Service Water System, planned for the scheduled Spring,1995 refueling outage, could be implemented. In References (c) and (d), NRC requested that Vermont Yankee inform the Staff should any changes in this planned schedule occur. l 941222o1so 94121s "

J D PDR ADOCK 05ooo271 P PDR

e .

4 VERMONT YANKEE NUCLEAR POWER CORPORATION United States Nuclear Regulatory Commission December 15,1994 Page 2 Our present schedule calls for implementation of this design change during the 1996 refueling outage. This revised schedule is based on the work that needs to be completed to properly prepare for the 1995 refueling outage and the acceptability of the current situation.

Should you have any questions with regard to our planned schedule, please contact this office.

Sincerely, VERMONT YANKEE NUCLEAR POWER CORP.

/

-,P M .

ames P. Pelletier Vice President, Engineering JPP/gmv cc: USNRC Region i Administrator USNRC Resident inspector - VYNPS USNRC Project Manager - VYNPS l

l l

1 I

l l

l