ML20133D632
| ML20133D632 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 07/22/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20133D610 | List: |
| References | |
| TAC-56844, TAC-56845, NUDOCS 8508070397 | |
| Download: ML20133D632 (2) | |
Text
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UNITED STATES g
NUCLEAR REGULATORY COMMISSION 2
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- j WASHINGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N05. g4 AND 98 TO FACILITY OPERATING LICENSE NOS. DPR-24 AND DPR-27, WISCONSIN ELECTRIC POWER COMPANY POINT BEACH NUCLEAR PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-266 AND 50-301 Introduction By letter dated January 30, 1985, Wisconsin Electric Power Company (licensee) requested changes to the Appendix A Technical Specifications appended to the operating licenses for the Point Beach Nuclear Plant Units 1 and 2.
The changes would modify the underfrequency trip setpoint for the reactor coolant pump trip, change the related basis and correct a typographical error wherein an incorrect technical specification number is referenced in a basis to the Technical Specifications.
Discussion and Evaluation i
The underfrequency trip setpoint for the reactor coolant pumps is designed to l
protect the reactor against departure from nucleate boiling (DNB) in the event of reduced primary system flow resulting from electrical system disturb-ances which cause frequency decay.
In support of the proposed Technical Specification change for reducing the l
.underfrequency setpoint, a reanalysis of the complete loss-of-flow transient l
was performed by Westinghouse. The analysis methodology and assumptions were l
consistent with the FSAR analysis and the same as those used for the analysis of this incident for licensing the use of Westinghouse designed 14x14 optimized I
fuel assemblies (0FA). The following assumptions were made in the analysis in l
support of the proposed Technical Specification changes:
1.
Reactor coolant system (RCS) flow was assumed to decay linearly in response due to a frequency decay at a constant rate of 5 Hz per second. The l
5 Hz per second decay rate has been determined to be conservative for the Wisconsin Electric system.
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2.
Reactor trip occurs on a RCP underfrequency signal at a setpoint of 54.5 Hz.
l 3.
Reactor trip delay time was assumed to be 0.6 seconds.
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- The analysis bounded cores consisting entirely of standard fuel, cores con-sisting entirely of 0FA fuel, and transition cores containing both fuel types. Operation at either 2000 psia or 2250 psia was considered. The difference between the Unit I and Unit 2 steam generators was also taken into j
account in order to cover both Point Beach units. The resulting DNBR for the limiting fuel type using the Westinghouse Improved Thermal Design Procedure (ITDP) and the WRB-1 correlation minimizes at 1.65 at about 3.4 seconds following the beginning of the transient. This is well above the allowable DNBR of 1.3.
Specific evaluations for standard fuel using standard methods were also performed.
The Westinghouse ITDP and WRB-1 correlation were used for both 0FA fueled cores and transition cores.
Based on our review, the staff finds that the proposed underfrequency trip setpoint will provide adequate margin over the accepted DNBR limit. Therefore, the licensee's proposed changes are acceptable.
ENVIRONMENTAL CONSIDERATION These amendments involve a change in the installation or use of facility components located within the restricted area as defined in 10 CFR Part 20.
The staff has determined that the amendments involve 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 1
Commission has previously published 4 proposed finding that these amendments involve no significant hazards consideration and there has been no public coment on such finding. Accordingly, these amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 651.22(c)(9).
Pursuant to 10 CFR 651.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendmerts.
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 operatton in the proposed manner, and (2) such activities will i
ba conducted in compliance with the Comission's regulations, and the issuance of the amendments will not be inimical to the comon defense and security or to the health and safety of the public.
Date: July 22, 1985 Principal Contributors:
W. Jensen T. Colburn 2
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