ML19207A903
| ML19207A903 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 07/23/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19207A902 | List: |
| References | |
| NUDOCS 7908220588 | |
| Download: ML19207A903 (2) | |
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uMITED STATES NUCt. EAR REGULATORY COMMISSION f, 1(,j WASHINGTON. D. C. 20666
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SAFETY EVALUATION BY THE OFFICE OF NUCLcAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 58 TO FACILITY OPERATING LICENSE NO. DPR-46 NEBRASKA PUBLIC POWER DISTRICT COOPER NUCLEAR STATION DOCKET NO. 50-298 1.
Introduction By telecopied letter dated June 21, 1979, the Nebraska Public Power District (the licensee) prorosed changes to the Technical Specifications of Facility Operating License No. DPR-46 for the Cooper Nuclear Station.
The proposed changes would permit the faciMty to be operated at a power level of about 40% for a 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> continuous period between the dates of June 22, 1979 and June 25, 1979 with the containment deinerted.
We have made certain char.ges to the licensee's June 21 proposal which we have discussed with the 1;censee.
Evaluation The following discusses *.he areas of safety they are affecting by the licensee's request and acr evaluation of these areas.
1.
Deinerting the Containment - In early 1976, the licensee submitted a proposed combustible gas control system design that would not require inerting.
This system design was predicated on a lower metal-water reaction which was being considered as part of i,p n osed change to the Conmission's regulations.
A new rule (i.e., 10 CFR 50.44), which became effective on November 27, 1978, would ailow the assumed metal-water reaction to be based on the resultr of :he Emergency Core Cooling System analyses requirements of h CFR 50.46.
Althou-h the staff has not completed its review of the proposed system design, the preliminary analyses, f acluding the licensee's proposal to reduce power to approximately 40%, indicate that inerting would not be required for Cooper Station under the provisions of the new rule, and that an air-dflution system would be an effective means of manually controlling combustible gas concentrations following a LOCA. Based r these analyses, we conclude that combustible gas control measures could be provided by means other than inerting.
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. 2.
Operating the Containment Purge Valves - We are presently reviewing the adequacy of containment purging for the Cooper Nuclear Power Station. We have not completed our review, however, the licensee has stated that there is adequate justification that the purge valves are designed to close following a LOCA. On this basis we conclude that the licensee can open the purge valves during the short time period that he needs for containment access.
3.
Maintaining Delta P Control _ - The licensee h been operating the plant with a pressure differential betwec, the drywell and wetwell to reduce the effects of pool dynamics following a LOCA. The licensee has comitted to maintain this Delta P except for very sho '. time periods required for ingress and egress to the contain-ment. This should be approximately 2 - 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> during the 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> time period. We have concluded that this short time makes extremely unlikely the occurrence of a LOCA while a Delta P is not maintained.
In addition to the above justifications, the Technical Specifications do allow deinerting and a lack of Delta P control for the same periods, i e.,
approximately 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> under shutdown conditions followed by an imediu.a startup.
Becauce of all of the above, including the low probability of an accident occucring during this time period, we conclude that the temporary change '.o the Technical Specificatirns is acceptable.
Environmental Consideration We have determined that the amendment does not authorize a change in effluent types or tctal amounts nor an increase in power level and will not result in any s nnificant environmental impact. Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR Section 51.5(d)(4), that an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
Conclusion We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the prooosed manner, and (3) such activities will be conducted in compliance with the Comission's regulations and the issuance of this amendment will not be inimical to the comon defense and security or to the health ind safety of the public.
95 Dated:
July 23, 1979 Sis.TS