ML20154G613

Comment Supporting Proposed Rule 10CFR50 Re Alternative Method for Leakage Rate Testing.Believes Method Accurately Calculates Containment Leakage Rate W/Less Statistical Uncertainty than Total Time Method

ML20154G613
Person / Time
Site:	FitzPatrick
Issue date:	04/01/1988
From:	Brons J POWER AUTHORITY OF THE STATE OF NEW YORK (NEW YORK
To:	NRC OFFICE OF THE SECRETARY (SECY)
References
FRN-53FR5985, RULE-PR-50 53FR5985-00017, 53FR5985-17, NUDOCS 8805250006
Download: ML20154G613 (2)

Text

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4# Authority April 1, 198 J PN-88-011, NrY h 3; M8 IPN-$O Secretary of the Commission U.S. Nuclear Regulatory Commission Washington, DC 20555 Attention: Docketing and Services Branch

Subject:

James A. FitzPatrick Nuclear Power Plant Docket No. 50-333 Indian Point 3 Nuclear Power Plant Docket No. 50-286 Alternative Method for Leakay. Rate Testina

Reference:

NRC Notice of Proposed Rule, 53 FR 5985, dated February 29, 1988.

Dear Sir:

The New York Power Authority has reviewed and evaluated the proposed amendment to 10 CFR 50, Appendix J concerning an alternative method for leakage rate testing of primary containment structures (Reference 1). The Authority endorses the Mass Point rathod and its inclusion into the acceptance criteria for the Type "A" Primary Containment Integrated Leakage Rate Test (PCILRT). This method accurately calculates the containment leakage rate with less statistical uncertainty than does the Total Time method with the generally used uncertainty analysis.

The Technical Specifications for the Authority's FitzPatrick plant require a Mass Point analysis, while Appendix J requires the Total Time method. Therefore, the Authority performed both Mass Point and Total Time analyses for the 1987 FitzPatrick PCILRT. This allows a comparison of the two techniques using identical containment conditions.

Measured leakage rates using the two methods were consistant and differed by only 5%. However, the reported leak rates (based on the Bechtel BN-TOP-1 method for calculating the 95% upper confidence level) show the Total Time results to be 40% greater than the Mass Point result. This comparison demonstrates that both methods produce consistent containment leakage measurements and that the Total Time statistical analysis is inherently overconservative. This conservatism may necessitate a long duration (24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) test to allow the Total Time upper confidence level (UCL) to meet the leakage rate acceptance criteria, i

8805250006 800401 PDR PR 50 53FR5905 PDR g

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I i The rapid convergence of the Mass Point 95% UCL to the j measured leakage rate restits in a more accurate reported 4 leakage rate. It also allows a shorter duration test without a ,

I significant change in the reported results. This is especially :

- true when test data is collected more frequently than once/ hour.

The Fitzpatrick Mass Point results met the leakage rate l acceptance criteria (including UCL) in approximately 2 1/2 hours I and fully stabilized within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> using data collected overy 20 i l minutes. The Commission should allow a minimum test duration of 1

8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> when using a Mass Point analysis in accordance with the

. provicions of ANSI /ANS 56.8-1987, i

Snould you or your staff have any questions regarding this '

matter, please contact Mr. J. A. Gray, Jr. of my staff.

I Very truly yours, I w #

foin C. Brons .

Executive Vice president [

i Nuclear Generation i .

l cc: U.S. Nuclear Regulatory Commission 475 Allendale Road l l King of Prussia, PA 19406 [

l Office of the Resident Inspector i

U.S. Nuclear Regulatory Commission ,

J P.O. Box 136 l

Lycoming, NY 13093 Resident Inspector's Office l Indian Point Unit 3 l U. S. Nuclear Regulatory Commission l P. O. Box 337 l

Buchanan, NY 10511 i Mr. Harvey Abelson Project Directorate I-1

{ Division of Reactor Projects - I/II l U.S. Nuclear Regulatory Commission i 11555 Rockville Pike Rockville, MD 20852

! Joseph D. Neighbors, Sr. Project Manager l

Project Directorate I-1 Division of Reactor Projects I/II U. S. Nuclear Regulatory Commission Mail Stop 14B2 Washington, D. C. 20555

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