ML20203N051
| ML20203N051 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 09/19/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20203N050 | List: |
| References | |
| NUDOCS 8609230112 | |
| Download: ML20203N051 (3) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.137 TO FACILITY OPERATING LICENSE NO. DPR-49 IOWA ELECTRIC LIGHT AND POWER COMPANY
-CENTRAL IOWA POWER C00 PERATIVE COHN BELT POWER COOPERATIVE UUANE ARNOLD ENERGY CENTER DUCKEl NO. 50-331
1.0 INTRODUCTION
By letter dated October 12, 1984, the Iowa Electric Lignt ano Power Company (the licensee) requested revision to the Technical Specifications for the Duane Arnold Energy Center (DAEC) reflecting elimination of the requirement for a differential pressure system between the drywell and the wetwell of the DAEC Mark I containment.
e The differential pressure system was established as an interim measure as a part of the Mark I Containment Short Term Program, for the purpose of providing a reduction in potential loads during a postulated loss of coolant accident (LOCA) and an associated restoration of the margins of safety to approximately two.
Subsequently, as a part of Mark I Containment Long Term Program, the licensee modified the containment to establish acceptable structural safety marg 1ns to withstand dynamic loads under conditions of loss of coolantaccident(LOCA). Therefore, the differential pressure system is no longer needed.
2.0 EVALUATION In July 1980 the NRC issued NUREG-0611. " Safety Evaluation Report, Mark I Containment Long-Term Program," to address the NRC acceptance criteria for the Mark I Containment Long-Term Program. As a result of additional evaluation work, the NRC 1ssued Supplement I to NUREG-0611 in August 1982.
On December 30, 1982, the licensee submitted to the NRC a Plant Unique Analysis Report (PUAR) for the DAEC Mark I Containment Long-Term Program. The PUAR documented the licensee's reassessment of the DAEC containment to withstand the additional design loads postulated to occur during a LOCA, or a safety relief valve (SRV) discharge event.
the reanalysis was performed in accordance with NUREG-0611 and its 8609230112 860919 PDR ADOCK 0500 1
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supplement. The licensee concluded that upon completion of all modifications addressed in the PUAR the containment system design safety margin was restored to the safety margin intended at the time of plant licensing for operation. The PUAR analyses were performed with a drywell to wetwell differential pressure of zero.
By letter dated September 11, 1985, the NRC transmitted to Iowa Electric Light and Power Company the Safety Evaluation (SE) covering the PUAR for the DAEC Mark I Containment Long-Term Program.
In the SE the NRC concluded that acceptable safety margins had been established for all pool dynamic loads under LOCA and SRV discharge loads, and that the established margins for structural integrity under LOCA conditions are acceptable. Therefore, the licensee plans to eliminate the differential pressure system and change the Technical Specifications accordingly.
The NRC Senior Resident Inspector at the DAEC has informed the staff that all the facility modifications addressed by the licensee in the PUAR have been completed. The completion of these modifications have restored the design safety margin of the DAEC containment system to e
the safety margin intended at the time the plant was licensed for operation. The staff has also reviewed the requested Technical Specification changes and finds that they are consistent with the elimination of the differential pressure systems and are acceptable.
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3.0 ENVIRONMENTAL CONSIDERATION
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This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, I
and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued l
a proposed finding that the amendment involves no significant hazards consideration and there has been no public ccmment on such finding.
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
4.0 CONCLUSION
We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Comission's 1
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i regulations, and the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of. the public.
Principal Contributor:
F. Maura Dated: September 19, 1986 s
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