ML20080F948
| ML20080F948 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 01/23/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20080F945 | List: |
| References | |
| NUDOCS 8402130205 | |
| Download: ML20080F948 (2) | |
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UNITED STATES y
g NUCLEAR REGULATORY COMMISSION E.'
s WASHINGTON, D. C. 20555 o
y}Y SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATInti SUPPORTIfG AMEN 0 MENT NO. 92 TO LICENSE fl0. DPR-49 IOWA ELECTRIC LIGHT AND POWER COMPAHY CENTRAL IOWA POWER COOPERATIVE CORN BELT POWER COOPERATIVE DOCKET NO. 50-331 DUANE ARNOLD ENERGY CENTER 1.0 Introduction By letter dated May 4,1983, the Iowa Electric Light and Power Company (the licensee) made ap' plication to amend the Technical Specifications for the Duane Arnold Energy Center (DAEC) in order-to of the turbine control valve in a synchronous manner. permit operation Currently, at rated power, three of the valves are fully open and the fourth is cnly 32 percent open.
In order to reduce the probability of turbine blade damage the licensee wishes to operate the valves so that all are at approximately 54 percent open at full power, 2.0 Evaluation In'the event of load rejection without bypass, the proposed change in the control valve operation *'would result in a more rapid reduction in steam flow due to more rapid valve closure, a larger pressure pulse resulting in collapsing of the voids, ard an inadeouate margin of operating critical power ratio (CPR) over the minimum critical power ratio (MCPR) limits.
The licensee reanalyzed this event assuming new valve settings to determine the adequacy of the CPR margin above the MCPR limit. The results of the licensee's analysis indicate that the operating limits of CPR must be changed to assure that the resulting CPR is within the range of values expected for this quantity.
Based on the results of his analysis the licensee has proposed to increase the operating CPR margin above the MCPR from 1.25 to 1.27 for 8x8 fuel and from 1.27 to 1.29 for 8x8R fuel. The licensee has shown that this corrective change -
to the operating CPR margin would completely offset the increased challenge to the MCPR limits that would be likely when the operation of the turbine control valves is changed, and would return the systen performance characteristic to those that.were' found acceptable for the
'ca.e of_ load rejection without bypass transient analyzed by the staff 8402130205 040123 4
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Therefore, the turbine control valve modification in conjunction with the revised CPR operating limits is not likely tn result in a change in.the frequency of MCPR limit challenges or their cnnsequences in the event of a transient due to lead rejection without bypass.
We have reviewed the licensee's analysis and find that the licensee's analysis was performed using an NRC-approved computational code (0DYN) and that the resulting CPR values proposed by the licensee are within the range of values expected for this cuantity. We, therefore, conclude that the proposed Technical Specification changes are acceptable.
3.0 Environmental Considerations 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 standpo, int of environmental impact, and pursuant to 10 CFR 951.5(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.
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 ot the public.
Principal Reviewer:
W. Brooks Dated:
January 23, 1984 O