ML17201J420
| ML17201J420 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 09/01/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17201J419 | List: |
| References | |
| RTR-REGGD-01.097, RTR-REGGD-1.097 GL-82-33, NUDOCS 8809080227 | |
| Download: ML17201J420 (3) | |
Text
y UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NULCEAR REACTOR REGULATION COMMONWEALTH EDISON COMPANY DRESDEN STATION UNIT NOS. 2 AND 3
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DOCKET NOS. 50-237 AND 50-249 CONFORMANCE TO REGULATORY GUIDE 1.97
1.0 INTRODUCTION
Conmonwealth Edison was requested by Generic Letter 82-33 to provide a report to NRC describing how the post-accident monitoring instrumentation meets the guidelines of Regulatory Guide (R.G.) 1.97 as applied to emergency response facilities. The licensee responded to Item 6.2 of the generic letter on August 1, 1985: Additional information was provided by letters dated November 4, 1985, January 31, 1986, July 1, 1986, and October 28, 1987.
A detailed review and technic.ai evaluation of the licensee's submittals was performed by EG&G Idaho, Inc., under a contract to the.NRC, with general supervision by the NRC staff *. This work was reported. by-*£G&G in Technical Evaluation Report (TER), "Conformance to Regulatory Guide 1.97:
Dresden-2 and -3, 11 dated January 1988 (attached).
We have reviewea** this report and concur with the conclusion that the licensee either conforms to, or has adequately justified deviations from, the guidance of R.G. 1.97 for each post-accident monitoring variable except for the variable neutron flux.
2.0 EVALUATION CRITERIA Subsequent to the issuance of the generic letter, the NRC held regional meetings in February and *March 1983 to answer licensee and applicant
- questions and concerns regarding the NRC policy on R.G. 1.97. At these meetings, it was established that the NRC review would only address exceptions taken to the guidance of R.G. 1.97..
Further, where licensees or applicants explicitly state that instrument systems conform to provisions of the regulatory guide, no further staff review would be necessary for those items. Therefore, the review performed and reported by EG&G only addresses exceptions to the guidance of R.G. 1.97. This Safety Evaluation addresses the licensee's submittals based on the review policy described in the NRC regional meetings and the conclusions of the review as reported by EG&G.
3.0 EVALUATION We have reviewed the evaluation performed by EG&G contained in the attached TER and concur with its bases and findings.
The licensee either 8809080227 880901 PDR ADOCK 05000237 p
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- conforms to, or has provided an acceptabfe justification for deviations from the guidance of R.G. 1.97 for each i>OSt-accident monitoring variable except for the variable neutron flux.
R.G. 1.97 recormnends Category 1 neutron flux instrumentation to monitor reactivity control. The licensee has provided neutron flux monitoring instrumentation which conforms to the Category 1 recommendations of R.G.
1.97 except for environmental and seismic qualification of cables, detectors, and detector drives that are inside the primary containment.
The justification provided by the licensee for not fully qualifying the neutron flux monitoring instrumentation is that a scram can be verified by monitoring scram relay position, scram valve position, control rod drive scram accumulator pressure,*scram discharge volume, makeup flow, RCS pressure, and torus pressure.
The staff does not agree with the licensee's justification. In LOCA situations, monitoring of neutron flux is a direct indication of return to criticality rather than a lagging, indirect indication, as provided by the licensee's proposed inltrumentatton. Thus, the staff finds the licensee's
- justification unacceptable.
However, the staff finds the licehsee's justification an acceptable basis for interim operation of the exi~ting neutron flux monitoring instrument~tion in conjunctio~~with the above mentioned alternate instrumentation.
The staff has been informed that industry has developed wide range neutron flux monitoring systems that satisfy the Category 1 criteria of R.G 1.97.
Therefore, it is the staff's position that the licensee should evaluate these newly developed systems and install neutron flux monitoring instrumentation which fully complies with the Category 1 criteria of R.G. 1.97.
4.0 CONCLUSION
Based on the staff's review of the enclosed TER and the licensee's submittals, we find that the Dresden Station Unit Nos. 2 and 3 design is acceptable with respect to conformance to R.G. 1.97, Revision 2, except for the instrumentation associated with the variable neutron flux.
It is the staff's position that information provided by the neutron flux monitoring instrumentation is needed by the operator in the evaluation of proper reactivity control. It is also the staff's position that the licensee should install neutron flux monitoring instrumentation which fully complies with the Category 1 criteria of R.G. 1.97. The existing neutron flux monitoring instrumentation conforms to the Category 1 criteria of R.G. 1.97 except for seismic and environmental qualification.
Based on the above alternate instrumentation the staff concludes that the existing neutron flux monitoring instrumentation is acceptable for interim operation pending satisfactory implementation of a fully qualified indication system.
- An appropriate implementation schedule w_ill be developed by the project manager via discussion with the licensee. Once the schedule is established, the licensee is required to inform the Conunission, in writing, of any significant changes in the established completion schedule identified in the staff's Safety Evaluation and when the action has actually been completed.
Principal Reviewer:
B. Marcus Dated:
. J..'
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