ML20138J658
| ML20138J658 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 12/05/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20138J652 | List: |
| References | |
| NUDOCS 8512170601 | |
| Download: ML20138J658 (2) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.127 TO LICENSE NO. OPR-49 IOWA ELECTRIC LIGHT AND POWER COMPANY CENTRAL IOWA POWER COOPERATIVE CORN BELT POWER COOPERATIVE DUANE ARNOLD ENERGY CENTER DOCKET NO. 50-331
1.0 INTRODUCTION
In a letter dated July 18, 1985, the Iowa Electric Light and Power Company (the licensee) requested additions to Technical Specifications for Duane Arnold Energy Center (DAEC) in response to the modifications required by NUREG-0737 Item II.K.3.28 (Qualification of ADS Accumulators). The item II.K.3.28 requires that air or nitrogen accumulators for the Automatic Depressurization System (ADS) valves have the capability to be cycled open five times at design pressure up to 100 days following an accident.
The licensee proposes to decrease the system leakage rate in the lines from the Nitrogen Supply System to the ADS accumulators and ensure that adequate Nitrogen will remain in the accumulators to meet the above stated requirement of item II.K.3.28.
The hard seated check valve in each line is to be replaced by a check valve with a non-metallic, secondary soft seat.
The licensee suqqests that the existing check valves could probably uphold the requirements. However, the proposed modification would " provide an additional margin of safety" in the leakage rate and futher ensure that the nitrogen supply will be adequate to meet the reuqirements of II.K.3.28.
Since a soft seat is less resistant to wear than is a hard seat, the licensee proposes additional surveillance of the soft seated check valves.
The Technical Specification revision includes leak testing of the four valves during each refueling outage to verify that the maximum acceptable system leakage rate of 25 sec/ min is not exceeded.
The licensee also proposed to correct a typographic error in Table 3.2-8 changing 120 sec see to 120 sec 5 sec.
2.0 EVALUATION The soft seats being proposed by the licensee as a replacement for the metallic seats for the check valves will be more likely to degrade than the metallic seats under normal operational conditions. However, the licensee proposes that during each refueling outage it will perform a simulated automatic actuation test of the ADS and leak test the nitrogen accumulator check valves to assure that any degradation of the soft seats will be 8512170601 851205 ADOCK 050 g331 PDR PDR P
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e detected and remedied before it becomes a problem. We have reviewed the licensee's request and based on the review of the seal material and estimates of its failure frequency, we agree with the licensee that the proposed frequency of surveillance is adequate to mitigate the consequences of the use of the soft seats. We, therefore, find that the requested Technical Specification changes are acceptable. The correction of a typographic error in Table 3.2-B is an administrative change and is acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
S This amendment involves a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change in surveillance requirements. 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, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding.
Accordingly, this 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 this 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 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.
Principal Contributor:
A. Gilbert Dated: December 5, 1985 1
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