ML20206U051

Safety Evaluation Re Util 860513 Response to Reg Guide 1.97. Licensee Provided Acceptable Justification for Deviating from Guidance of Reg Guide for Each post-accident Monitoring Variable Except for Quench Tank Temp & Neutron Flux

ML20206U051
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	09/29/1986
From:	NRC
To:
Shared Package
ML20206T139	List: ML20206T135 ML20206T964 ML20206U051
References
RTR-REGGD-01.097, RTR-REGGD-1.097 GL-82-33, TAC-51362, NUDOCS 8610070287
Download: ML20206U051 (4)

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SAFETY EVALUATION TROJAN NUCLEAR PLANT DOCKET NO. 50-344 CONFORMANCE TO REGULATORY GUIDE 1.97 INTRODUCTION AND

SUMMARY

Portland General Electric Company (the licensee) was requested by Generic Letter 82-33 to provide a report to the NRC describing how the post-accident monitoring instrumentation meets the guidelines of Regulatory Guide 1.97 as applied to emer-gency response facilities. The licensee's response specific to Regulatory Guide 1.97 was provided by letter dated December 28, 1984. Additional information was provided by letter dated May 13, 1986.

A detailed review and technical evaluation of the licensee's submittals was per-formed by EG&G Idaho, Inc., under contract to the NRC, with general supervision

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by the NRC staff. This work was reported by EG&G in the Technical Evaluation Report (TER), "Conformance to Regulatory Guide 1.97, Trojan Nuclear Plant," dated July 1986 (attached). We have reviewed this report and concur with the conclusion that the licensee either confonns to, or is justified in deviating from, the guidance of Regulatory Guide 1.97 for each post-accident monitoring variable except for the variables quench tank temperature and neutron flux.

EVALUATION CRITERIA Subsequent to the issuance of the generic letter, the NRC held regional meetirgs in February and March 1983 to answer licensee and applicant questions and concerns regarding the NRC policy on Regulatory Guide 1.97. At these meetings, it was noted that the NRC review would only address exceptions taken to the guidance 8610070287 86092 PDR ADOCK0500bR P

\  ! of Regulatory Guide 1.97. Furthermore, where licensees or applicants explicitly state that instrument systems conform to the provisions of the regulatory guide,

it was noted that no further staff review would be necessary. Therefore, the review performed and reported by EG&G only addresses exceptions to the guidance of Regulatory Guide 1.97. This Safety Evaluation addresses the licensee's submittals based on the review policy described in the NRC regional meetings l

and the conclusions of the review as reported by EG&G.

EVALUATION We have reviewed the evaluation performed by our consultant contained in the enclosed TER and concur with its bases and findings. The licensee either conforms to, or has provided an acceptable justification for deviating from the guidance of Regulatory Guide 1.97 for each post-accident monitoring variable except for the (a) quench tank temperature and (b) neutron flux.

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(a) Regulatory Guide 1.97 recommends a temperature range of 50 to 750*F for this variable. The licensee has provided instrumentation with a range of 0 to 300'F. The licensee states that this instrumentation is used to maintain the tank temperature below 200'F during normal operation and that a temperature near 300*F would indicate an abnormal condition. The staff concludes that the instrumentation range for this variable should be adequate to remain on scale during all accident and post accident conditions. Therefore, the licensee should provide 1

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a range that will a; a minimum read the saturation temperature corresponding to the rupture disk relief pressure (338 F).

b. Regulatory Guide 1.97 recommends Category 1 instrumentation for this variable. Category I requirements include full redundancy to satisfy the single failure criteria. The licensee has committed to add a single Category I neutron flux channel, however, this will still not satisfy the single failure criteria. The licensee states that automatic post-accident boron injection flow rates and concentrations are designed to provide adequate shutdown margin for accidents without measuring the boron concentration. Baron injection of 2000 ppm from the refueling water storage tank and accumulators can be verified with Category 1 and 2 instrumentation. Any boron dilution would be detected by periodic sampling using the Post-Accident Sampling System. The plant also has existing neutron flux monitors which are not environmentally qualified for post accident monitoring, they are only qualified to perform their immediate safety function of reactor protection.

The staff concludes that the above instrumentation and sampling means are not satisfactory substitutes for a redundant qualified neutron flux monitoring channel. The use of the Post-Accident Sampling Sys-tem is much slower than a neutron flux monitoring channel, and the existing flux monitor systems are not environmentally qualified for post accident. The licensee should provide instrumentation for this variable that will comply with the Regulatory Guide 1.97 recommendations.

CONCLUSION Based on the staff's review of the enclosed Technical Evaluation Report, and the licensee's submittals, we conclude that the Trojan Nuclear Plant design is acceptable with respect to conformance to Regulatory Guide 1.97, Revision 2, except for the variables pertaining to the (a) quench tank temperature and (b) neutron flux. It is the staff's position that the licensee install and have operational, instru-mentation that meets the recommendations of Regulatory Guide 1.97, Revision 2, for these variables. This instrumentation should be operational at the first scheduled I

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l outage _of sufficient duration, but no later than startup following the second refueling outage after receipt of this report.

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