ML19324B848

Provides NRC W/Test Acceptance Criteria for Alternate Test of CO2 Suppression Sys,Per 891025 Meeting.Ability to Contain CO2 at Appropriate Concentration for Required Duration,As Well as Ability to Withstand Dynamics of Discharge,Verified

ML19324B848
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	10/30/1989
From:	Tremblay L VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BVY-89-101, NUDOCS 8911080388
Download: ML19324B848 (2)

Text

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i L VERMONT YANKEE <

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• NOcLEAR POWER CORPORATION l,

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e Ferry Road, Brattleboro, VT 053017002 ,,,,,  ;

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{/J ENGINEERING OFFICE 580 MAIN STREET BOLTON, M A 01740 (508)7794 711 e

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October 30,1989 1 BVY 89101' U. S.' Nuclear Regulatory Commission ; .;

Washington, DC 20555 Attention: Document Control Desk '

References:

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

. b) letter, USNRC to VYNPC, NVY 89-108, dated 5/18/89  !

c) Letter, VYNPC to USNRC, BVY 89-48, dated 6/2/89 ,

d) Letter, USNRC to V YNPC, NVY 89-1*12, dated 8/21/89  ;

Subject:

Acceptance Criteria for Alterrate Test of CO2 Suppression System .,

Dear Sir:

The purpose of this letter is to provide the NRC with the test acceptance criteria requested during the October 25,1989 meeting at NRC offices with Vermont Yankee, Pennsylvania Power

. and Light, and NRC. The meeting was a follow-up to Reference (d), in which it was indicated that NRC was willing to consider an alternative method of testing in lieu of full discharge testing.

. As discussed at the meeting, Vermont Yankee' believes a reasonable and technically sound l'" attemate approach to a full discharge test is available. The National Fire Protection Association (NFPA) has recently issued Appendix B to the NFPA 12A Halon Standard. This Appendix provides an approved " Enclosure Integrity Procedure" which directly determines an Eqmvalent l Leakage Area (ELA) for fraoms similar to our Cable Vault. If the test procedure is adjusted for the density and concentration of CO2, there is substantial engineering basis to apply this same test to our Ceble Vault enclosure. The Halon Technical Committee has recommended adoption of this '

1rocedure to other gaseous systems and NFPA is working toward endorsing this test method in

.ieu of full discharge testing for CO2 systems (NFPA 12).

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p Upon congletion of the Enclosure Integrity Procedure, the actual equivalent leakage area of the room is quantified. The ability to contain CO2 at the a apropriate concentration for the required 4 duration, as well as the room's ability to withstand the c ynamics of a discharge, is verified. The ,

7; .. dynamics of the discharge can then be accurately predicted by entering the ELA, room geometry, and quantities of CO2 discharged into an NFPA accepted and proven computer model. The l

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location of the CO2/ air descending interface (crit'.11 concentmtion)is identified as a function of

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s-U. S. Nuclear Regulatory Commission Page Two Vermont Yachee proposes to perform the Enclosure Integrity Test Procedure on October 31,1989 and November 1,1989 for the cable vault enclosure. The success of the test will be established upon verification that the descending interface is greater than or equal to 7 feet after 10 minutes. 'Ihe descendi ig interface is defined as the room height below which the concentration of CO2 is greater than or equal to 50%

We believe that a satisfactory Enclosure Integrity Test, along with the required "as built" system verifications, will provide the assurance that the Cable Vault CO2 Fire Suppression System will perform as designed. Vermont Yankee will forward the completed test results to the NRC u si completion of the Enclosure Integrity Pmcedure. We further understand that in order for the NRC to accept this alternative test metha. l a favorable benchmark test, comparing the results of an i actual full discharge test for a CO2 system to results using the enclosure integrity procedure, must also lx provided to the NRC.

• Please contad this office with any concerns or questions that you may have.

Very truly yours, Vermont Yankee Nuclear Power Corporation d0L4L.N Leonard A. Tremblay, Jr.

Senior Licensing Engineer l

cc: USNRC Region I Administrator l

USNRC Resident Inspector - VYNPS USNRC Project Manager- VYNPS l

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