ML20126F659

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Containment Leak Rate Testing, Monthly Progress Rept for June 1983
ML20126F659
Person / Time
Site: Surry, Crystal River, 05000000
Issue date: 06/30/1983
From: Naus D
OAK RIDGE NATIONAL LABORATORY
To: Arndt G
NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
Shared Package
ML20126E434 List:
References
CON-FIN-B-0489, CON-FIN-B-489, FOIA-85-143 NUDOCS 8506170575
Download: ML20126F659 (2)


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June 30,1983 j Mr. Gunter Arndt Mechanical / Structural Engineering Branch Division of Engineering Technology NL 238 Office of Nuclear Regulatory Research U.S. Nuclear Regulatory Commission Washington, DC 20555

Dear Gunter:

This letter sumarizes our progress on the Containment Leak Rate Testing investigations (Fin. No. B0489) for the month of June 1983.

Technical Highlights One difference between the ANSI standard and the proposed revision to Appendix J that has not yet been discussed concerns the acceptability criterion for the results of Type B and C tests. To be acceptable the ANSI standard requires the combined leakage rate (including the upper confidence limit) of Type B and C tests to be less than 75 percent of the maximun allowable leakage rate. The proposed revision to Appendix J states that the combined leakage rate of all Type B and C tests must be less than 60 percent of the maximum allowable leakage rate at all <

times. The differences in these criteria are two-fold. The ANSI stand-ard includes an tupper confidence limit on the combined leakages determined by adding the standard deviation of the leakage rate to the leakage rate, while the proposed revision to Appendix J does not. The second difference regards the 75 percent versus 60 percent criterion. ,

i The inclusion of the measurement error through the use of the standard deviation is very worthwhile. Presentation of the leakage rate data in this manner provides a better indication of the accuracy of the Type B and C leak tests. Because the ANSI standard uses 75 percent with a confidence limit and the proposed revision to Appendix J uses 60 percent without a confidence limit, the only way the two could provide the same result is if the standard deviatirn of the combined leakages is 15 per-cent of the maximum allowable leak rate. With the sophisticated instru-mentation available today such a large standard deviation is very un-likely which means the criteria in the proposed revision to Appendix J are more conservative than the ANSI criteria.

8506170575 850325 FOIA PDR REYTBLAB5-143 PDR [

f Mr. Gunter Arndt 2 June 30,1983 The remaining question concerns the degree of conservatism to use in evaluating the results (i.e., what percentage of the maximum allowable leak rate). Recog-nizing the poor performance of Type A tests following the successful completion of local leak testing programs, no reason is evident to justify relaxing the currently enforced 60 percent rule. In fact, except for the knowledge of potential changes elsewhere in the local leak testing programs, the 60 per-cent criterion should probably be more strict. The 60 percent rule should stand until the effects of potential changes in the local leak testing pro-grams can be evaluated.

A computerized literature search of the DOE energy data base and Nuclear Science Abstracts has been initiated to uncover sources of information concerning the leakage characteristics of containment valves with respect to temperature and seating time. Both domestic and foreign sources are being examined but noth-ing of value has been obtained yet.

Plant visits to observe leak testing have been tentatively scheduled for the middle of July at Crystal River and the end of July at Surry.

Expenditures Oct. Nov. Dec. Jan. Feb. Mar. Apr. M June Expenditure ($K) 7.2 8.9 7.8 8.9 9.2 9.4 7.5 8.7 8.7* I Cumulative ($K)** 14.2 23.1 30.9 39.8 49.0 58.4 65.9 74.6 83.3

  • Estimated
    • Program Total Sincerely, D. J. Naus DJN:ege cc: J. R. Dougan