ML20053C507
| ML20053C507 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 05/10/1982 |
| From: | Siegel B Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20053C505 | List: |
| References | |
| NUDOCS 8206020246 | |
| Download: ML20053C507 (2) | |
Text
g nagIg UNITED STATES
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7, NUCLEAR REGULATORY COMMISSION g,
- y WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT N0. 79 TO FACILITY OPERATING LICENSE N0. DPR-46 NEBRASKA PUBLIC POWER DISTRICT COOPER NUCLEAR STATION DOCKET N0. 50-298 Author
B. Siegel INTRODUCTIGN By telecopied letter dated March 23, 1982 the Nebraska Public Power District (the licensee) proposed changes to the Technical Specifications of Facility Operating License No. DPR-46 for the Cooper Nuclear Station. The proposed changes would permit the facility to be operated during startup with the containment deinerted up to 60% of the licensed thermal power for a 48-hour continuous period.
between the dates of March 22, 1982 and March 25, 1982.
DISCUSS:0N The Cooper Nuclear Station (CNS) shutdown the weekend of March 20, 1982 due tc generator voltage fluctuations. On March 22, 1982 plant startup commenced including containment inerting.
During the return to power a failure in the ductwork used to inert the containment with nitrogen was discovered.
This failure resulted in enough nitrogen leaking into the reactor building that it was perceived that the technical specification inerting requirement could not be met.
This requirement permits a 24-hour period to reduce the containment oxygen concentration to less than 4% by volume subsequent to placing the reactor in the RUN mode following shutdown. An alternate path for inerting the containment, which bypassed and isolated the failed section of the ductwork, was utilized and the licensee requested a Technical Specification change that would allow operation of an additional 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in a deinerted condition.
As a safety precaution the licensee decided to limit operation to 60% of licensed thermal power during this time.
EVALUATION The following discusses the areas of safety related to the licensee's request and our evaluation of these areas.
1.
Operating the Containment Purge Valves - We are presently reviewing the adequacy of containment purging for the Cooper Nuclear Power Station.
The licensee in a January 4,1979 letter provided. justification that 8206020246 820510 PDR ADOCK 05000298 P
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2 the purge valves are designed to close against the dynamic forces of a LOCA.
Based on this information and recent' information provided by the licensee in response to our containment purge and vent review, we conclude that the purge valves would close in the unlikely event of a LOCA during the i
time perio'd thepwere o~p'en toibmolete containment purging.
~
2.
Maintaining Delta P Control - The licensee has been operating the plant with a pressure differential between the drywell and wetwell to reduce the effects of pool dynamics following a LOCA.
However, the licensee, as a result of the Mark I Containment Program, has truncated the downcomers and made structural modifications to the torus which eliminates the need for maintaining the Delta P control.
The licensee has stated this will be documented in the Plant Unique Analysis for CNS which will be submitted in April 1982. On this basis we conclude the licensee can operate without maintaining Delta P control for the short period involved.
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 inmediate startup.
Because of all of the above, including the low probability of an accident occurring during this time period and operation at no greater than 60% of licensed thermal power to significantly reduce the severity of any accident, we conclude that the temporary change to the Technical Specifications is acceptable.
ENVIRONMENTAL CONSIDERATION We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant 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 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 proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Dated:
May 10,1982 9
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