ML20245D465
| ML20245D465 | |
| Person / Time | |
|---|---|
| Issue date: | 06/09/1988 |
| From: | Plumlee G NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Mike Williams NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| Shared Package | |
| ML20245D469 | List: |
| References | |
| NUDOCS 8806280385 | |
| Download: ML20245D465 (2) | |
Text
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JUN 0 91969 FEMORANDUM FOR:
Mark H. Williams, Chief Trends and Aralysis Branch Division of Safety Programs, AEOD THR0'IGH:
Robert L. Dannig, Chief J
Trendt end Patterns Section C
Trends and Pa tterns Analysis Branc.
Division of Safety Programs, AE0D FROM:
G.L. Plumlee III, Senior Plant Systems Engineer Trends and Patterns Section Trends and Patterns Analysis Branch Division of Safety Programs, AE0D
SUBJECT:
A TECHNICAL BASIS FOR GRANTING TEST FREQUENCY RELIEF The subject technical review is enclosed for your consideration.
This study was initiated as a result of a July 8,1987, request from Larry C. Shao (NRR) to Edward L. Jordan in which NRR requested AE0D's assistance in developing a methodology to put the IST testing requirements on the best technical basis.
Based on EG8G's efforts under FIN D6151 and my directions, a method as presented in EG8G's report EGG-NTA-8067, "A Technical Basis for Grant'.ng Test Frequency Relief with Application to Automatic Depressurization System Valves," dated April 1988, has been developed that can be used to form a technical basis for granting testing frequency reliefs and will in general inprove the IST program. This mathod was benchmarked utilizing the BWR automatic depressurization systen (ADS) valve NPRDS database failures as a trial case. The sample calculations used to berchmark the method showed that for the industry in general, ADS valve testing frequency would be unacceptably short if one wanted to limit the upper bound on the probability of two or more failures to five percent or less for all degraded aiid immadiate failures combined. However, consideration of only the imediate failures results in acceptable test frequencies for many cases.
The enclosed technical review is based on EG&G's work as documented in the enclosed proprietary report EGG-NTA-8067. As directed, based on the fact that i
the NPRDS database failures were not validated and the site-specific NPRDS
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' data is proprietary, the enclosed methodology was prennted without providing "i
the specific data values and qualitative and q;aatitativa results obtained.- I L.
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propose that the enclosed technical report ba *crwarded by memorandum from
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Nnvak to Shao in order to ~ cinse out NRR's request.
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.G.L. Plumlee III, Senior Plant Systems Engineer Trends and Patterns Section l
Trends and Patterns Analysis Branch Division of Sa'ety Prograns, AE00 g
Enclosure-As stated i
cc w/ enclosure:
T. Novak' l
C. Gentillon, INEL-
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