ML15113A085
| ML15113A085 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 03/02/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML15113A084 | List: |
| References | |
| NUDOCS 8403150344 | |
| Download: ML15113A085 (2) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 127 TO FACILITY OPERATING LICENSE NO. DPR-38 AMENDMENT NO.127 TO FACILITY OPERATING LICENSE NO. DPR-47 AMENDMENT NO.124 TO FACILITY OPERATING LICENSE NO. DPR-55 DUKE POWER COMPANY OCONEE NUCLEAR STATION, UNITS NOS. 1, 2, AND 3 DOCKETS NOS. 50-269, 50-270 AND 50-287 INTRODUCTION The NRC staff previously reviewed and found acceptable the Adequacy of Station Electric Distribution System Voltages for Oconee Nuclear Station, Units Nos. 1, 2 and 3. The staff's Safety Evaluation and associated Technical Evaluation Report were transmitted to Duke Power Company (DPC or the licensee) via correspondance dated March 21, 1983. The voltage analysis submitted by DPC as part of the documentation to be reviewed by the staff indicated that when a unit startup transformer is shared between two or more generating units, the distribution voltages at the safety buses become unacceptable. DPC agreed to implement Technical Specification (TS) changes which would prohibit the connection of more than one generating unit's load to a single startup transformer.
EVALUATION In a letter dated March 17, 1983, DPC submitted proposed TS changes which incorporate Limiting Conditions for. Operation in the event of loss of a startup transformer. The limiting conditions are:
- 1. Technical Specification paragraph 3.7.2(i)1 states a startup transformer may be inoperable for a period not to exceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for test or maintenance provided the underground feeder from Keowee Hydro Station, Transformer CT4 and one 4160V standby bus is verified operable within one hour of loss of the transformer, and every eight hours thereafter.
During the above 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, the remaining operable startup transformers can be shared between units. However, prior to exceeding 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, each unit must be aligned only to its assigned startup transformer.
- 2. Technical Specification paragraph 3.7.2(i)2 states that in the event a startup transformer is disabled due to an unplanned reason, one unit shall be placed in cold shutdown within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> with its loads powered from the standby buses. The remaining operable startup transformers can be shared between generating units during the same 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. However, prior to exceeding 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, each unit must be aligned only to its assigned startup transformer.
8403150344 840302 PDR ADOCK 05000269 P
SUMMARY
The above proposed TS changes, when implemented, will assure adequate distribution of voltages at the Class IE buses in the event of loss of a startup transformer. We, therefore, find the proposed TS changes 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 §51.5(d)(4), that an environmental impact statement, or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of these amendments.
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 these amendments will not be inimical to the common defense and security or to the health and safety of the public.
Dated:
March 2, 1984 Principal Contributors:
H. Emami and J. Suermann