ML20196A357

Forwards Addl Pages Not Included in Rept on Containment Safety at Vermont Yankee,

ML20196A357
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	06/23/1988
From:	Rooney V Office of Nuclear Reactor Regulation
To:	Mcknight J NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8806300019
Download: ML20196A357 (4)

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+ UNITED STATES 8 ~ _f,k NUCLEAR REGULATORY COMMISSION 5 l WASHING TON. D. C. 20555

%,...../ June 23, 1988 Docket No. 50-271 NOTE: ' Jim McKnight, Control Document Room FROM: V. L. Rooney, Project Manager i

SUBJECT:

"REPORT ON CONTAINMENT SAFETY AT VERMONT YANKEE;" additional pages The enclosed two pages, which were not included in the original submittal, should be added to copies of the "Report on Containment Safety at Vermont i Yankee, April 29, 1988", Transmitted by letter from Vermont Yankee dated May 74, 1988 (accession number 8805310001).

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Vernon L. Rooney, P ject Manacer Project Directorate I-3 Division of Reactor Projects I/II i

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Afi.ao '8813:55 YANKEE ATOMIC FR41ItGH41 MA P.o2 l

,- CHAPTER THIRTY-FIVE INTERSERVICE AGREEMENT WITH THE "

NEW ENGLAND POWER SYS'IEM

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Reference:

ASTA, IV.C.3, p. 6)

On'e ASTA recommendation was to reevaluate and reconfirm service agreements with the Vernon hydroelectric station and the New England Power System with regard to station blackout scenarios.

The Vermont Yankee Containment Safety Study demonstrated that the Vemon hydroelectric station is a major additional safety factor that is essentially unique among nuclear plants. It.is a back-up source of power to Vermont Yankee of very high reliabilty. The 10-unit hydrostation is located less than a mile from Vermont Yankee. A dedicated, normally energized line between the hydro plant and Vermont Yankee, can be connected directly to either of Vermont Yankee's emergency electrical busses by remote operation of circuit breakers from the control room. The capacity of the hydro plant a sufficient to meet emergency needs on either of the two busses. These busses supply power to large pumps which are ,

important because they provide additional water to the reactor vessel, spray water to the drywell and torus, and provide. residual heat removal from the torus or the reactor vessel.

In studies to determine how to mitigate a severe accident, several recommendations were made to address the survivability, ,

maintenance and procedural use of the Vernon tie line. While these i recommendations have been discussed elsewhere, see Chapters 17 and 3, their implementation is of less value if the hydrostation does not recognize the priority that should be given to Vermont Yankee during a scenario in which it loses all AC electrical power. The ASTA study recommended that interservice agreements be confirmed between Vermont Yankee and the owners and operators of the Vernon hydroelectric station.

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j 15 12 P.2 CHAPTER TWELVE SAMPLING THE TORUS FOR RADIOACT. IVITY

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Reference:

Containment Safety Study,

p. 143, 5.6.5.3.1.E; Appendix E 1.1.8, p. E8) e During certain severe accident scenarios, water is injected into either the reactor vessel or to the primary containment. Water to the reactor vessel provides a make up supply for water that is lost because of boiling. Water to the containment is used for drywell sprays to provide steam condensation (this results in pressure suppression of the containment). Regardless of the injection path of the water, the water itself eventually falls into the suppression pool (i.e., the torus which is the containment's "wet well"). A maximum water level in the suppression pool, however, is necessary for two reasons: to prevent flooding of the vacuum breakers that connect to '

the drywell (this could result in excessive differential pressure between the drywell and the suppresalon pool; as a result, containment integrity could be threatened); and, to avoid the increased hydrodynamic loading of the submerged components within the pool (increased loading on the submerged components would alter their response during .a pressure releano from the primary contairhnent, leading to a possible suppression pool rupture). The normal methods for lowering suppression pool water level are either to provide a flow path to the radioactive waste processing facility by means of pumps in the residual heat removal system, or to use valves installed on the bottom of the suppression pool to drain water to the reactor building's sumps where it can later be pumped to the radioactive waste processing facility.

When the water from the torus reaches the radioactive waste facility, it is processed to remove radioactive isotopes and other contaminants and then is transferred to the condensate storage tank

r ee b ACCELERATED DISTRIBUTION DEMONSTRATION SYSTTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:8805310001 DOC.DATE: 88/05/24 NOTARIZED: NO 1

DOCKET #

FACIL:50-271 AUTH.NAME Vermont Yankee Nuclear Power Station, Vermont Yankee 05000271 MURPHY,W.P. AUTHOR AFFILIATION RECIP.NAME Vermont Yankee Nuclear Power c orp.

MUR LEY , T. E . RECIPIENT AFFILIATION Office of Nuclear Reactor Regulation, Director (Post 870411

SUBJECT:

Forwards "Rept on Containment Saf ety at Vermont Yankee," dtd 880524. Review not requested.

p OISTRIBUTION CODE: A001D COPIES RECEIVED:LTR '

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ENCL SIZE: f fITLE: OR Submittal: General Distribution ~~ ~-

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NOTES:

D RECIPIENT COPIES REC:' TEN?

ID CODE /NAME COPIES S LTTR ENCL ID C ' (ME LTTR E"C!

PDl-3 LA 1 0 PD1-3 '

ROONEY,V 5 5 1 1 f INTERNAL: ARM /DAF/LFMB 3 0 A NRR/ DEST /CEB 8H i NRR/ DEST / ADS 7E 1 1

-' 1 NRR/ DEST /ESB 8D 1 1

• r'T.'"~2 : .

NRR/ DEST /RSB 6E 1 p

NRR/DOEA/TSB 11 1 1 NUDOCS-ABSTRACT 1 NRR/PHAS/ILRB12 1 1 1 OGC 15-B-18 n>

REG FILE 01 1 1 0 1 RES/DE/EIB 1 1 EXTERNAL: LPDR g 1 1 NRC PDR NSIC 1 1 1 1 i

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S TOTAL NUMBER OF COPIES REQUIRED: LTTR 22 ENCL 19

l VERMONT YANKEE NUCLEAR POWER CORPORATION AD 5, Box 169 Ferry Road. Brattleboro. VT 05301

,q' IVY 68-42 l

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vice President and Manager of Operations t6021257 527' May 24, 1988 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attn: Office of Nuclear Reactor Regulation Dr. T.c w-w r n:---+--

Dear Sir:

In accordance wi th a enclosed, ecent vercal req-est f rom your staf f, I have for your information, at Vermont Yankee", dated April a copy 29, of our "Report on Containment Safety 1988.

review of this document. We are not requesting ycur I

This report was generated by our Public Relations Department to sum-marize and describe the current status of all our Containment Improvement /

Severe Accident initiative items for the State of Vermont. It is not a technical report and therefore does not represent a definitive follow-up effort to the "Vermont Yankee Containment Safety Study", dated August 1986, which was previously riviewed by your staff. As dascribrJ in our March 1, (

1988 letter to your staff, Vermont Yankee will await the hAC's pending for-mal guidance prior to resolving any other severo accident issues. I If you have further questions, please do not hesi+m+a

+0 contact me.

Very truly yours, N [

Warren P. Murphy Vice President and Manager of Operations

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