ML20246A837

Forwards Safety Evaluation Re Combustible Gas Control Evaluation Rept Submitted by to Document Compliance w/10CFR50.44(c)(3)(ii).Conclusion That Plant Meets 10CFR50.44 Requirements Noted

ML20246A837
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	06/23/1989
From:	Wang A Office of Nuclear Reactor Regulation
To:	Mroczka E CONNECTICUT YANKEE ATOMIC POWER CO.
Shared Package
ML20246A841	List: ML20246A837 ML20246A854 ML20247M620 ML20247M636
References
TAC-68355, NUDOCS 8907070105
Download: ML20246A837 (3)

Text

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o g UNITED STATES v

.8 o NUCLEAR REGULATORY COMMISSION y, t WASHINGTON, D. C. 20555 ,

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% ,,, June 23, 1989 Docket No. 50-213 Mr. Edward J. Mroczka Senior Vice President Nuclear Engineering and Operations Connecticut Yankee Atomic Power Company i

P. O. Box 270 Hartford, Connecticut 06141-0270 {

l 1

Dear Mr. Mroczka- I

SUBJECT:

COMBUSTIBLE GAS CONTROL EVALUATION FOR THE HADDAM NECK PLANT (TAC NO. 68355) J By letter dated March 4,1983, the Connecticut Yankee Atomic Power Company (CYAPCO) submitted its combustible gas control evaluation report for the Haddam Neck Plant to document its position regarding compliance with the l requirements of 10 CFR 50.44(c)(3)(ii). This analysis, assuming stainless steel fuel, concluded that combustible gas accumulation inside the containment would not reach the flammable limit of 4% by volume until approximately 13 )

months following a design basis LOCA assuming no purging or repressurization, j Subsequently, CYAPC0 provided additional infomation in a letter dated November 17, 1986 and concluded the time to reach flammability would be 8.5 months rather than 13 months as originally esiculated. Based on this analysis, CYAPC0 concluded that the plant need not be provided with the i hydrogen recombiner capability called for in 10 CFR 50.44(c)(3)(11). By

. letter dated May 19, 1989, CYAPCO stated hydrogen recombiner capability could .l be established and would be one of the options evaluated should combustible gas control be necessary. In addition CYAPC0 stated that based on its analysis, assuming zircaloy fuel the amount of hydrogen generated for stainless steel or zircaloy cladding is equivalent.

The staff performed an independent confirmatory analysis of hydrogen generation in accordance with Regulatory Guide 1.7 guidelines using the COGAP computer program with assistance of the Los Alamos Laboratory (LANL). The staff analysis ,

assumed zircaloy fuel and concluded that the hydrogen concentration would reach  ;

the flamable limit in 6 months assuming no purging or repressurization. The staff concluded that CYAPCO did not follow the guidelines of Regulatory Guide {<

1.7 when analyzing long term hydrogen generation which resulted in an incorrect accumulation time estimation to reach the flammability limit. However, since the plant has a large containment volume and the hydrogen accumulation rate is low, the staff has concluded that given the 6 months to reach the flammability limit CYAPC0 has sufficient time to establish an external hydrogen recombiner t i

capability following a LOCA and that no further action is required by CYAPC0 to  !

comply with 10 CFR 50.44.

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Mr. Edward'J. Mroczka  : June 23,-1989 I r

Based on the above the staff concludes that the Haddam Neck Plant meets the-requirements of 10 CFR 50.44. In addition, this conclusion also bounds-the )

upcoming zircaloy conversion. The staff's safety evaluation is provided as . d Enclosure 1. .The staff considers ISAP Topic No.1.63, " Hydrogen Control"

complete with the issuance of this' safety evaluation. If you have any questions or comments _ please call me at-(301)492-1313.

1 Sincerely, j l'

Original signed by Alan B. Wang,' Project Manager Project Directorate I-4  ;

Division of Reactor Projects I/II Office of Nuclear Reactor Regulation

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. Enclosure As stated-cc w/ enclosure:

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Mr. . Edward J. Mroczka I Connecticut Yankee Atomic Power Company Haddam Neck Plant '

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Gerald Garfield, Esquire R. M. Kacich, Manager l Day, Berry and Howard Generation Facilities Licensing l' ' Counselors at Law Northeast Utilities Service Company

' City Place Post Office Box 270 Hartford, Connecticut 06103-3499 Hartford, Connecticut 06141-0270 W. D. Romberg, Vice President D. O. Nordquist Nuclear Operations Director of Quality Services Northeast Utilities Service Company Northeast Nuclear Energy Company L Post Office Box 270 Post Office Box 270 Hartford, Connecticut 06141-0270 Hartford, Connecticut 06141-0270 Kevin McCarthy, Director Regional Administrator Radiation Control Unit Region I 1 Department of Environmental Protection U. S. Nuclear Regulatory Commission i State Office Building 475 Allendale Road Hartford, Connecticut 06106 King of Prussia, Pennsylvania 19406 Bradford S. Chase, Under Secretary Board of Selectmen Energy Division Town Hall Office of Policy and Management Haddam, Connecticut 06103 80 Washington Street Hartford, Connecticut 06106 J. T. Shedlosky, Resident Inspector Haddam Neck Plant D. B. Miller, Station Superintendent c/o U. S. Nuclear Regulatory Commission Haddam Neck Plant Post Office Box 116 Connecticut Yankee Atomic Power Company East Haddam Post Office RFD 1, Post Office Box 127E East Haddam, Connecticut 06423 East Hampton, Connecticut 06424 G. H. Bouchard, Unit Superintendent Haddam Neck Plant RFD #1 Post Office Box 127E East Hampton, Connecticut 06424 i

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