ML20204F891

Safety Evaluation Supporting Type a Containment Leakage Test Results,As Modified & Stated in 860228 Summary Technical Rept & 860228 Proposal to Use Current Schedule for Subsequent Type a Testing

ML20204F891
Person / Time
Site:	Grand Gulf
Issue date:	07/25/1986
From:	NRC
To:
Shared Package
ML20204F889	List: ML20204F885 ML20204F891
References
TAC-60862, NUDOCS 8608060232
Download: ML20204F891 (1)

Text

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Enclosure SAFETY EVALUATION GRAND GULF NUCLEAR STATION UNIT 1 CONTAllMENT INTEGRATED LEAKAGE RATE TEST By letter dated February 28, 1986, the licensee (Mississippi Power and Light Company) submitted the summary technical report for the Containment Integrated LeakRateTest(CILRT))completedonNovember4,1985atGrandGulfNuclear Station Unit 1 (GGNS-1 . The licensee stated that the CILRT did not meet the acceptance criteria of Appendix J until certain containment penetrations were isolated. Therefore, the test was defined as a failure. The sources of leakage (i.e., main steam line and spare standby liquid control line isolation valves) were identified and isolated. The isolation of these penetrations reduced the leakage to allow successful completten of the Type A test. Under the provisions of Appendix J, paragraph III.A.6(a), if any Type A test fails to meet Appendix J acceptance criteria, the licensee is required to submit a test schedule applicable to the subsequent Type A tests. The licensee proposes that the schedule for subsequent Type A testing remain as currently specified in Technical Specification 4.6.1.2.a for GGNS-1.

In regard to the potential impact on the success or failure of a A test, the staff's position is that when repair or adjustments (periodic ras)are Type made to valves prior to the Type A test sequence as a result of excessive leakage or other reasons, local leak tests must be perfomed on the affected valves to determine the leakage rates before and after the ras. The "as found" Type A test result should be obtained by adding the difference between the affected valve leakage before and after ras to the overall measured Type A test result. The periodic Tyn A test would be called a " failure" if the "as found" Tyw A test result witt appropriate correction from local leak rates exceeds tie acceptance criteria of Appendix J.

The licensee has measured the "as left" leakage following post-test normal closure or repair of the affected valves and added it into the Type A test result. The licensee did not attempt to add the valve leakage before the ras to the "as found" Type A test result since the leakage was indeterminate.

The licensee, however, did define the test as a failure. The staff believes that determining the "as found" Type A test result by adding the "as left" pe A valveleakageafterRAstotheT{zero"testmeasurementisconservativesince the licensee in essence assumed valve leakage after these penetrations were isolated.

Consequently, the licensee submitted CILRT results, as modified and stated in the summary technical report, are acceptable. Furthermore, the staff concurs -

with the Itcensee's proposal to use the current schedule for subsequent Type A 4(

testing.' Appendix J requires more frequent CILRTs only when two successive Type A test faileres occur. Only one Type A test failure has occurred which does not constitute a basis for a more frequent CILRT schedule.

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l l 0608060232 060725 PDR ADOCK 05000416 P PDR

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