ML20063E411

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Requests Exemption from 10CFR50.44(c)(3)(ii) Requirement That Mark I Containments That Rely on Purge/Repressurization as Primary Hydrogen Control,Be Provided W/Either Internal Re Combined or Capability to Install External Recombiner
ML20063E411
Person / Time
Site: Vermont Yankee Entergy icon.png
Issue date: 07/06/1982
From: Heider L
VERMONT YANKEE NUCLEAR POWER CORP.
To: Eisenhut D
Office of Nuclear Reactor Regulation
References
FVY-82-81, NUDOCS 8207130413
Download: ML20063E411 (2)


Text

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VERMONT YANKEE

.iNUCLEAR POWER CORPORATION 2.C.2.1 FVY 82-81

. RD 5, Box 169. Ferry Road, Brattleboro, VT 05301 ENGINEERING OFFICE

- 1671 WORCESTER ROAD

- July 6, 1982 FRAMINGHAM. MASSACHUSETTS 01701

  • TEL.EPHONE 617-872-8100 United States Nuclear Regulatory Commission Washington, D. C. 20555 Attention: Office of Nuclear Reactor Regulation Mr. D. G. Eisenhut, Director Division of Licensing

References:

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

(b) Letter, T. J. Dente to D. G. Eisenhut, dated June 24, 1982 (c) Letter, VYNPC to USNRC, FVY 82-73, dated June 17, 1982 (d) Final Interim Hydrogen Control Rule Published in the Federal Register on December 2,1981, p.p. 58484-58486

Subject:

Exemption Request

Dear Sir:

The purpose of this letter is to request an exemption from the requirements of 10CFR50.44(c)(3)(ii), which requires that Mark I containments that rely on purge /repressurization as the primary means of hydrogen control, be provided with either an internal hydrogen recombiner or the capability to install an external recombiner, following a postulated LOCA. We do not feel that the requirements of this regulation are applicable to Vermont Yankee.

The basis for this request results from the findings of a study entitled,

" Generation and Mitigation of Combustible Gas Mixtures in Inerted BWR Mark I Containments - NEDO 22155," conducted by General Electric Company on behalf of the BWR Owners Group and submitted to the NRC via Reference (b). The significant findings of the study are as follows:

1. Net oxygen generation in a gamma / neutron flux occurs only in a boiling regime since radiolysis and recombination of H 2O occur at approximately equal rates in a subcooled regime.
2. thder conservatively postulated accident conditions, boiling can be stopped in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. This fixes the total amount of 02 generated.
3. An inerted containment is maintained with a minimum amount of 02 , as regulated by Technical Specifications. If the 02 generated per Item 2 above is added, the 0 2 -H2 mixture will not contain sufficient 02 to be combustible.
4. The BWR's covered by this study need not rely on the use of purge /

repressurization as the primary means of controlling combustible gases, and consequently the regulation does not require hydrogen recombiner capability.

8207130413 020706 PDR ADOCK 05000271 p PDR

9 VEHMONT YANKEE NUCLEAR POWER CORPORATION Mr. D. G. Eisenhut June 29, 1982 Page 2 The results of the study indicate that the existing inerted BWR Mark I containment design is adequate for control of combustible gases without the need for hydrogen recombiners or containment venting. Therefore, in accordance with 10CFR50.12, Vermont Yankee hereby requests an exemption from the requirements of 10CFR50.44 (c)(3)(11).

We believe the justification provided above forms an adequate basis for our request for exemption. We trust that this information will allow you to act on our request in a timely fashion. If you have any need for further information, please contact us.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION L. H. Heider Vice President JBS/ tan

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