ML20108F479

Suppl to Kewaunee Nuclear Power Plant 1984 Integrated Leak Rate Test Rept

ML20108F479
Person / Time
Site:	Kewaunee
Issue date:	08/20/1984
From:	WISCONSIN PUBLIC SERVICE CORP.
To:
Shared Package
ML20108F455	List: ML20108F453 ML20108F479
References
N1-67.1A, TAC-49131, NUDOCS 8503120449
Download: ML20108F479 (7)

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January 22, 1985

, . Attachment to Letter from D. C. Hintz to W. S. Little t

Supplement to -

Kewaunee's 1984 ILRT Report

, Originally Submitted August 20, 1984 i

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• Mr. W. S. Little January 22, 1985

~Page 1 Introduction This report presents the 'as-found' containment leakage rate calculation for the

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"Kewaunee Nuclear Plant Containment at the end of Cycle IX. Type C leakage, greater than the capacity of the local leak rate tester, was identified through a containment penetration with redundant isolation valves in series. The 'as-found' integrated leakage rate is determined by combining the directly measured containment leakage with a conservative measure of (pre-post) repair differen-4 tial leakage. The combination of the directly measured 1984 integrated leakage rate and the (pre-post) repair differential leakage could not be quantified.

This is considered a failure of the 1984 Type A test.

As stated in 10 CFR 50, Appendix J, V.B.3, upon failure of a Type A test the following points shall be covered in a summary report:

An analysis and interpretation of the test data The least squares fit analysis of the test data The instrumentation error analysis The structural conditions of the containment or components, if any, which contributed to the failure in meeting the acceptance criteria Results and analyses of the supplemental verification test employed to demonstrate the validity of the leakage rate test measurements shall also be included.

Section I of this report contains the 'as-found' leakage rate calculation and sections II through VI discuss the five (5) points required by 10 CFR 50,

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Appendix J, V.B.3.

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. January 22, 1985 Page 2 I. 'As Found' Containment Leak Rate Type B and C leakage tests were performed during the 1984 Refueling-Outage prior to the Type A test. This order of testing is consistent with KNPP Technical Specifications and exemptions granted to WPSC from Appendix J provided a conser-vative measure of (pre-post) repair differential leakage is added to the Type A i results.

When Type C leakage repairs are made prior to and during the same outage as a Type A test, (pre-post) repair differential leakage added to the Type A test will include improvements in the penetration's overall ability to isolate con-tainment; e.g.,

(1) Penetration with 2 testable isolation valves in series:

Before repair: Valve 1 leaks 8 SCFH Valve 2 leaks 6 SCFH

After repair

Valve 1 leaks 2 SCFH Valve 2 leaks 1 SCFH i ' Repaired leakage': 5 SCFH (2) Penetration with 2 testable isolation valves in series:

Before repair: Valve 1 leaks 8 SCFH Valve 2 leaks 6 SCFH After repair: Valve 1 leaks 2 SCFH i

Valve 2 leaks 5 SCFH

' Repaired leakage': 4 SCFH i

IMrc W.~ S.' Little

' January 22, 1985 Page 3 ' l Penetration geometries other than those with 2 testable isolation valves in

., , series will be evaluated on a case-by-case basis using appropriate conser-  ;

vatisms. -Type B leakage repaired prior to and during the same outage as a Type A test will also be evaluated on a case-by-case basis using appropriate conser-l vatisms. - -

1984 i

As-Found Integrated Leakage Rate Determination Kewaunee Nuclear Power Plant Table 1 Leakage Repaired in 1984 Prior to the Type A Test Penetration- Initial Final Repaired Repaired Leakage Leakage Leakage i- 12 0.088SCFH 0.053SCFH 0.035SCFH/1.54 x 10-5 wt.%/ day 111 >20SCFH 0.068SCFH >20SCFH/>8.77 x 10-3 wt.%/ day

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!AsFound = Leakage Rate + Type B&C Leakage Repaired i Integrated Determined ~ Prior to Type A Test Leakage Rate With Type A Test As Found Integrated = 0.0162 wt%/ day + 1.54 x 10-5 wt%/ day + >8.77 x 10-3 wt%/ day l Leakage Rate

= >0.0250 wt%/ day-

. Note'that the 'as-found' leakage rate is indeterminate. This resulted from the

, leakage through redundant isolation valves at penetration #11 exceeding the

! capability of the measuring device.

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!' I See LER 305-84-006~

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Mr. W. S. Little  !

January 22, 1985 ,

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-Since the 'as-found' 1984 Type A test results are not quantified it cannot be positively'said that the test passed, nor can it be positively concluded that the test was a failure. Conservatively, the 'as-found' 1984 Type A test is con-sidered a failure.

II. Analysis and Interpretation of the Test Data The 1984 ILRT test data were analyzed using the Mass Point Method (ANSI 56.8-1981). A summary of the data reduction method can be found in Appendix B of Kewaunee's 1984 ILRT Report (reference 1). The raw data and i

intermediate calculation results are in Appendix D of the same report.

The calculated leakage rate, 0.0162 wt%/ day (at 95% UCL), demonstrates the leak tightness of Kewaunee's Containment for Cycle X.

III. Least Squares Fit Analysis of the Test Data A least squares analysis was performed with the following as the independent and dependent variables, respectively:

[ Change in time Weight fraction of containment \

-measured from t=0 atmosphere remaining up to and

( , including data set i )

The s' ope of the curve is the containment leakage rate in weight fraction per hour and the y intercept is the weight fraction in containment at time zero.

This calculation was performed via computer; the data and results are found in the 1984 Kewaunee ILRT report, Appendix D.

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l Mr. W. S. Little January 22, 1985 Page 5 IV. Instrumentation Error Analysis _

A figure of_ merit analysis for the instruments used in the 1984 ILRT is pre-sented in Appendix B of the 1984 Kewaunee ILRT report (reference 1).- The analy-sis is consistent with ANSI 56.8-1981, Appendix G. The instruments were

, determined to be suitable for their intended use.

V. Conditions Which Contributed to Failure of the Type A Test Kewaunee's 1984 'as-found' Type A test was considered a failure since Type C j leakage greater than the capacity of the local leak rate tester was identified prior to the Type A test through redundant isolation valves.1

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O nuoE onace LD Mt Containment The leakage was repaired by replacing the seat ring gaskets in valves LD-4A and LD-4B and adjusting the stroke on LD-6. Note that LD-4A is in parallel with LD-4B which together are in series with LD-6. These repairs resulted in reducing the Type C leakage through penetration #11 from >20SCFH to 0.068 SCFH.

VI. Results and Analyses of Supplemental Verification Test Employed to Demonstrate the Validity of the Leakage Rate Test Measurement The condition which caused the Type A test failure was corrected prior to per-formance of the Type A tests, i.e., B and C tests were performed prior to the A I See LER 305-84-006

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test. Therefore, the relevant supplemental test is the same supplemental veri-fication test that illustrated acceptable results of Kewaunee's 1984 Type A 7

test. The supplemental test was successful and is described in section I.1 of Kewaunee's 1984 Type A test report (reference 1).

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