ML19329B733
| ML19329B733 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 04/08/1977 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19329B731 | List: |
| References | |
| NUDOCS 8002060741 | |
| Download: ML19329B733 (3) | |
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Davis Besse Unit 1 Safety Evaluation Report Supplement ! 3
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Docket # 50-346 7.2 Reactor Protection System In the Supplemental Safety Evaluation Reports (dated December 28, 1976 and March 2,1977) we identified our concerns and requests regarding the lack of separation in the applicants design between Class lE and non-Class lE wiring inside the Class lE logic cabinets (i.e., Reactor Protection and Engineered Safety features Actuation System) and in various control panels (identified in 7.9.3 of the SER).
In response, the applicant recently submitted a test proposal for our review which they will conduct on the above mentioned systems in order to demonstrate that their design as implemented will not degrade the safety systems bUow on.
acceptable level.
We have reviewed the type of tests that will be performed and the type of faults that the system will be subjected to.
We conclude that the proposed tests are acceptable in part. The applicant was advised that in addition to the presently proposed tests, we require that noise tests in accordance with 1111. Standard 19900, Section 4.6.11 (or equivalent) be conducted on the non-Class 1E circuits that interface with the Reactor Protection System, in order to satisfy the objectives of Section 4.6 of
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In addition, wa require that noise test. procedures (identified above) be! submitted to the staff a_nd found acceptable before
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power operation is permitted, and that the applicant complete these tests and submit the test results for our review prior to the first refueling or no later than 18 months of power operation, whichever comes first, i
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2 7.2 3ased cn the c;erating experier.c? of the Reacto Protection Synem and the Engineered Safety Features System on similar designs arJ our review of the qualification documentation presently submitted, we conclude that there is sufficient basis to allow ocwer operation for the,cariod stated, conditioned only on the satisfactory resolution of the noise tests requirements identified above. We will review the noise test procedures and the test results when submitted, and will report our evaluation in a supplement to this report.
7.9.2 Separationi Criteria Between Redundant Class lE Circuits Routed in Metal Conduits In the Supplement Safety Evaluation Report (dated March 2,1977), we identified that 'the applicants separation criteria for routing redundant f
Class lE cables in metallic conduit. allows less than one inch separation, i
and that the adequacy of such a design when subjected to internal faults t
was still under review. Subsequently, the applicant submitted their final test results, analysis, and the test procedures which they conducted l
(at our request) to justify the adequacy of their design.
We have reviewed these procedures, the test results, and the adequacy of the methods that were
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Used on these circuits to simulate abnormal conditions.
Based oiiour review of these tests and the separation requirements established at the i
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construction permit stage of review, we conclude that the design for redundant Class lE cabies in metallic conduit as implemented at'the Davis 7
Besse Unit-1 plant satisfies the objectives of GDC #22 and is therefore,
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l acceptable. Although, the applicants design criteria was compared to the t
recently established separation requirements, we do not believe that the i
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3 i.nceer ental :a?ety enrgin; which.iculd be achie/ed via these new requirements warrants backfitting their design to the new standards.
We do however, require that all future plant designs conform fully with the new established guides and standards.
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