ML13333A340
| ML13333A340 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 01/15/1979 |
| From: | Ottoson H Southern California Edison Co |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| TASK-06-06, TASK-6-6, TASK-RR NUDOCS 7901240143 | |
| Download: ML13333A340 (4) | |
Text
Southern California Edison Company P.O. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 January 15, 1979 Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D. C. 20555 Docket No. 50-206 San Onofre Unit 1 Reactor Containment Building Integrated Leak Rate Test
Dear Sir:
An integrated leak rate test was performed on San Onofre Unit 1 in September, 1978. The test was performed in accordance with the requirements of the Technical Specifications. Both the measured leak rate and supplemental verification test met the acceptance criteria set forth in the Technical Specifications.
Attached is a summary technical'report prepared in accordance with the reporting requirements of 10 CFR 50, Appendix J.
Sincerely, H. L. Ottoson Manager, Nuclear Generation cc: R. H. Engelken, Director U.S. Nuclear Regulatory Commission, Region V Office of Inspection and Enforcement
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24009
SAN ONOFRE NUCLEAR GENERATING STATION UNIT 1 January 11, 1979 REACTOR CONTAINMENT BUILDING INTEGRATED LEAK RATE TEST - September 20-24, 1978 INTROIDUCTION A type A reactor containment building integrated leak rate test (ILRT) was performed at San Onofre Unit 1 in September, 1978, during the Cycle VI-VII refueling outage. The test was performed pursuant to the applicable require ments of San Onofre Unit 1 Technical Specification 4.3. The previous such test was completed in March, 1977, 18 months prior to the September, 1978, ILRT. The results of that test were reported to the NRC by letter dated June 7, 1977.
In accordance with the reporting requirements of 10 CFR 50 Appendix J, paragraph V.B.3, this report presents the following information:
Results of the September, 1978, ILRT test and an analysis and interpretation of these results; Results and analyses of the supplemental verification test employed to demonstrate the validity of the September, 1978, ILRT test measurements; and Results of periodic type B and C penetration tests conduc ted since the previous ILRT in March, 1977.
TYPE A TEST RESULTS AND ANALYSIS The containment integrated leak rate test was accomplished during the period of September 20-24, 1978, within the test frequency specified in paragraph 4.3.I.C.a. of the Technical Specifications. The test was completed at a pressure in excess of the calculated peak containment presure, Pa, of 49.4 psig. Data for the absolute method of leak rate calculations was taken by an Autodata-9 microcomputer at 10 minute intervals. The data was then analyzed by the formula of ANSI N45.5-1972 and Bechtel Topical Report BN-TOP-1, "Testing Criteria for Integrated Leakage Rate Testing of Primary Containment Structures for Nuclear Power Plants," November 1, 1972. In accordance with ANSI N45.4-1972, a statistical analysis and linear least squares fit was performed on the raw data using the formulas of BN-TOP-1.
The leak rate results are summarized below for both the total time and mass plot methods. In each case, the calculated leak rate is less than 0.09 wt%/24 hours as required by paragraph 4.3.I.B. of the Technical Specifications.
-2 ILRT RESULTS SEPTEMBER, 1978 Measured Leak Rate 95% Upper (Least Squares Fit)
Confidence Level Total Time (Absolute Method) 0.043 0.053 wt%/24 hours Mass Plot (Absolute Method) 0.042 0.048 wt%/24 hours The test results for both the total time and mass plot calculations agree within instrument tolerances. The documented integrated leak rate was 0.043 wt%/24 hours using a least squares fit of the total time calculation for the absolute method referenced in ANSI N45.4-1972.
SUPPLEMENTAL VERIFICATION TEST RESULTS AND ANALYSIS Immediately following the type A test, a supplemental test was conducted in accordance with Technical Specification 4.3.I.B to demonstrate the validity of the leakage rate test measurements. A known quantity of air, measured through an orifice, was pumped back into the containment sphere. The quantity added, 436 lbm, was greater than the minimum of 349 lbm required to be added by the Technical Specifications as computed below:
Minimum amount of added air (lbm)
=
75% x total leakage allowed for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />
=
.75 x.0012 x 388211 lbm (initial containment mass)
=
349 lbm Comparing the quantity of air added, 436 lbm, with the change in containment air mass as measured by the leak rate instrumentation, 451 lbm, results in a difference of 15 lbm. This difference is within that allowed by the Technical Specifications as computed below:
Max allowable difference (lbm) =
25% x total leakage allowed in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />
=
.25 x.0012 x 388211 lbm
=
116 lbm
-3 Therefore, based on review of the above results, the supplemental test verified the accuracy of the ILRT measurements.
PENETRATION TESTING Penetration (Type B and C) testing was accomplished in accordance with the requirements of Technical Specification 4.3.11. The penetrations were tested by the pressure decay method using local panels and a total leakage was then determined.
The allowable leakage for all penetrations is 0.072%/24 hours of the mass of air in the containment at 49.4 psig. A summary of the results of all penetration testing accomplished between March 20, 1977 and September 20, 1978, is provided below.
These results, expressed as a percentage of the maximum allowable leakage of 0.072%, met the acceptance criteria of the Technical Specifications.
TEST DATE LEAKAGE (% OF ALLOWABLE) 04-07-77 43.52 04-25-77 55.89 08-24-77 55.02 08-26-77 54.92 09-17-77 79.67 10-06-77 65.27 02-21-78 62.91 04-13-78 73.05 05-20-78 71.24 09-19-78 82.01 09-19-78 35.83
SUMMARY
AND CONCLUSIONS
- 1.
The containment integrated leak rate test accomplished during September 20-24, 1978, was performed in accordance with the Technical Specifications.
- 2.
The integrated leak rate was found to be 0.043%. This meets the Tech nical Specification acceptance criteria of 0.09%.
- 3.
The pump back test performed at the conclusion of the integrated leak rate test verified the accuracy of the absolute method system within the Technical Specification acceptance criteria of 25% of.12 wt %/24 hours.
- 4.
Penetration tests performed between March, 1977, and September, 1978, met the acceptance criteria.
- 5.
The next integrated leak rate test will be conducted within the 26 month
(+4, -8) limit of Section 4.3.I.C.l.b. of the Technical Specifications (i.e., between March, 1980 and March, 1981).
MPS/k25a