ML20214W816

Safety Evaluation Granting Util 861015 Request for Release from Commitment to Compare Performance of on-line Instrumentation Vs Grab Sampling Techniques

ML20214W816
Person / Time
Site:	Grand Gulf
Issue date:	12/08/1986
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20214W804	List: ML20214W816
References
TAC-63150, TAC-63160, NUDOCS 8612100409
Download: ML20214W816 (2)

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WASHWGTON, D. C. 20655

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING ON-LINE INSTRUMENTATION VS GRAB SAMPLING TECHNIQUES MISSISSIPPI POWER AND LIGHT COMPANY GRAND GULF NUCLEAR STATION UNIT 1 DOCKET N0.50-416 i

1. INTRODUCTION The licensee made a commitment in a letter dated July 30,1982, to provide a report six months after exceeding 5% power (and no later than June 1,1983) comparing the performance of the post accident sampling system (PASS) on-line instrumentation with grab sample results determined 4

by analytical procedures. On-line monitoring consisted of analysis of reactor coolant radionuclides, chlorides, pH, conductivity and dissolved gas radionuclides and hydrogen. Grab samples were to be used as a backup.

This commitment was modified by letter dated August 25, 1983 to provide the comparison before the end of the first refueling outage. Because of

. operational difficulties, the on-line analyzers are now considered inoper-4 able and grab samples are used exclusively. Therefore, the licensee has requested (by letter dated October 15,1986) release from its coninitment to compare the performance of on-line instrumentation with grab-sample j results.

2. EVALUATION In our Safety Evaluation Report Supplement No.1 (NUREG-0831, December 1981) we stated that the PASS is designed for on-line monitoring with grab sampling as a backup which meets Criterion No. 8 of Item II-B.3 in NUREG-0737.

. .. The grab sampling capability is needed when an on-line instrument is inoperable. The licensee's commitment to compare the performance of the on-line instrumentation with the grab sampling results was voluntary. Since the on-line analyzers have experienced considerable operational difficulties, a comparison with grab sample results would be of questionable value. To l determine the PASS sample analysis accuracy and that the samples are representative of core conditions, the PASS sample is periodically compared with a sample taken at the same time from the normal sample station.

The PASS grab samples have indicated reasonable agreement with samples 4 from the normal sample station. Thus, the PASS grab samples meet the NUREG-0737. Item II-B.3 sample accuracy and sample representativeness criteria. The licensee intends to delete the use of the PASS on-line system and to rely on grab samples to meet Item II-B.3 of NUREG-0737.

Therefore, it is acceptable for the licensee to withdraw the commitment to compare the performance of on-line instrumentation versus grab sample

results determined by analytical procedures.

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3. CONCLUSION On the basis of our evaluation, we conclude that the licensee can be released from its commitment to compare the performance of PASS on-line instrumentation with grab sample results determined by analytical procedures.

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