ML20078G663
| ML20078G663 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 09/30/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20078G660 | List: |
| References | |
| TAC-47404, TAC-47405, NUDOCS 8310130062 | |
| Download: ML20078G663 (3) | |
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UNITED STATES 3
NUCLEAR REGULATORY COMMISSION 5
E WASHING TON, D. C. 20555
\\..... pl SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATIO_N SUPPORTING AMENDMENT NO. 74 TO FACILITY OPERATING LICENSE N0. DPR-24 AND AMENDMENT N0. 79 TO FACILITY OPERATING LICENSE NO. DPR-27 WISCONSIN ELECTRIC POWER COMPANY POINT BEACH NUCLEAR PLANT, UNIT NQS. 1 AND 2 DOCKET NOS. 50-266 AND 50-301 INTRODUCTION By letter dated June 30, 1982, (Ref. 1), Wisconsin Electric Power Company (WEPC) requested a revision to the technical specifications, (item 9 of Table 15.3.5-1) to change the undervoltage setpoint and the trip time delay of the degraded voltage relays. The proposed changes were submitted in response to the licensee's analysis for adequacy of station distribution system voltages (Ref. 2), and our Safety Evaluation dated January 6,1982, on the interim change request for the same item of the technical specifications (Ref. 3).
EVALUATION The present (interim) technical specifications list 3760 volts (90% of 4160) as the setpoint for the degraded voltage relay with a 30 second trip time delay. With a -2% drift, the relay'setpoint may be reduced to 3687 volts (88.6% of 4160) which is adequate for 4KV motors, but the 460 volt motors and downstream equipment will be subjected to less than 87% rated voltage at their terminals. These lower voltages and the related equipment ratings are discussed in detail in our Safety Evaluation dated January 6, 1982 (Ref. 3).
The proposed changes require the degraded voltage relays to be set at 3875 volts (93% of 4160) with a maximum of 60 seconds time delay. This voltage setpoint will assure 3797 volts (94.9% of 4000) at the terminals of 4KV motors and 414 volts (90% of 460) at the terminals of 460 volt motors.
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_2-Such a high voltage setpoint (93% of bus voltage) necessitates a longer time delay to prevent spurious tripping of the preferred power supply to the Class lE buses. The proposed time delay overrides the transient voltage dip due to starting of large motors (more than 30 seconds when both reactor coolant pumps start one after the other) and prevents inadver-tent trips. Also, the Class 1E equipment ratings, as evaluated in Reference 3, are well within the voltage setpoints of the loss of voltage relays submitted by the licensee in their letter of March 23, 1983 (Ref. 4).
The proposed voltage setpoints will ensure adequate voltage at the terminals of the Class lE equipment and the time delay will prevent spurious tripping of the preferred power supply to the Class 1E buses.
Based on our evaluation, we conclude that the proposed changes to the technical specifications (item 9 of Table 15.3.5-1) will ensure adequate protection of Class lE aquipment from sustained degraded voltage conditions and are, therefore, acceptable.
ENVIRONMENTAL CONSIDERATION We have determined that the amendments do 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 amendments involve an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 651.5(d)(4), that an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of the amendments.
CONCLUSION We have concluded, based on the consideration discussed above, that:
(1) there is reasonable assurance that the heatlh 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 the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Date: September 30, 1983 Principal Contributors:
T. Ahmed T. Colburn
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3-REFERENCES 1.
WEPC letter (C. W. Fay) to NRC (H. R. Denton) dated June 30, 1982.
2.
WEPC letter (C. W. Fay) to NRC (H. R. Denton) dated June 1, 1982.
3.
NRC letter (T. G. Colburn) to WEPC (Sol Burstein) dated January 6,1982.
4.
WEPC letter (C. W. Fay) to NRC (H. R. Denton) dated March 23, 1983.
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