ML20008F481
| ML20008F481 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 04/08/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20008F479 | List: |
| References | |
| NUDOCS 8104210063 | |
| Download: ML20008F481 (1) | |
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UNITED STATES I ',
i NUCLEAR REGULATORY COMMISSION W ASMNGTON. O. C. 20555 s,
SAFETY EVALUATIGN REPORT BY THE OFFICE OF NUCLEAR REACTOR REGULATION CRYSTAL RIVER - UNIT 3 OVERRIDE OF CONTAINMENT PURGE ISOLATION AND OTHER ENGINEERED SAFETY FEATURES ACTUATION SIGNALS Introduction Safety actuation signals for containment purge and ventilation valves have been inadvertently overridden and blocked at nuclear power plants, because of design deficiencies. Automatic closure of these valves during an accident would not have occurred when the signals were overridden or blocked. This problem was classified by the NRC as an abnomal occurrence (78-5). As a followup action, the NRC requested each licensee to take certain actions. The following is an evaluation of the electrical override portion of our long-tem review.
Evaluation The enclosed report (EGG-1183-4180) was prepared for us by EG&G, San Ramon, as part of cur technical assistance contract program. The report provides their technical evaluation of the design compliance with NRC-provided criteria.
The licensee has now completed modifications which added " low RCS pressure" as an automatic actuation signal for containment ventilation isolation. Comple-tion of these modifications brings the Unit into confomance with all NRC cri-teria except Cr terion #5.
Criterion d5 requires that the instrumentation and control systems provided to initiate ESF be designed and qualified as safety-grade equipment. The high radiation signals for containment ventilation isolation are not provided by safety-grade equipment.
Conclusions l
Based upon our review of the contractor's report, we conclude that the completed modifications bring the Unit into conformance with five of the six NRC-criteria.
When the revised Regulatory Guide 1.141 is approved (scheduled for June 1981), it will specify the upgrading of the radiation monitors to safety-grade quality.
We consider the contractor's report to be a final report, in that no further l
contractor effort is required for this Unit on this subject. We conclude that the Crystal River 3 plant design is acceptable regarding the short-tenn concerns on potential override of containment isolation and other engineered safety
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features.
Dated:
April 8,1981 l
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8104210 cb3 i
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