ML15112B023
| ML15112B023 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 07/24/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML15112B022 | List: |
| References | |
| NUDOCS 8107300300 | |
| Download: ML15112B023 (2) | |
Text
pAkREQ(O 110 RUNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 99 TO FACILITY OPERATING LICENSE NO. DPR-38 AMENDMENT NO. 99TO FACILITY OPERATING LICENSE NO. DPR-47 AMENDMENT NO. 96TO 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 By letter dated July 6, 1981, Duke Power Company (DPC) requested a revision to the Oconee Nuclear Station common Technical Specifications (TSs) which would allow testing for DC grounds.
Background & Evaluation On May 2, 1980, the NRC issued License Amendments 82, 82 and 79 to the Oconee Nuclear Station, Units 1,'2 and 3, respectively, which revised the TSs concerning Auxiliary Electrical Systems (Specification 3.7).
The 125 VDC systems are included in this Specification and the revision issued on May 2, 1980, removed the capability to isolate a unit's 125 VDC systems from the other unit's 125 VDC systems in order to locate the source of a ground should one occur. This deficiency was discovered by DPC and a proposed change was submitted by letter dated July 6, 1981, to correct the problem.
The 125 VDC systems for each of the three Oconee Units consist of redundant batteries, battery chargers and distribution systems.
Each of the redundant distribution systems also receives a backup source of power from another unit's 125 VDC system through Isolating Transfer Diodes.
Because of this method of providing a backup source of 125 VDC power, if a ground develops on any unit's 125 VDC system, it would be sensed on all the units. In order to determine the location of the ground, DPC proposed a change to allow the separation of each unit's 125 VDC system from its backup unit via the isolating and transfer diodes for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
By separating the units, it will then be evident where the ground exists, allowing further investigation and ultimately the repair of the grounded equipment.
68 io730'308io724 PDR ADOCK 05000269 P
-2 We have reviewed the DPC request and find it to be acceptable because even during the short period of time when the backup source of power has been removed, the affected unit will still have two redundant sources of 125 VDC power available from separate batteries, battery chargers and distribution systems to ensure proper operation of all necessary 125 VDC equipment.
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)2 that an environmental impact statement, or negative declaration and environ
,mental 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) because the amendments do not involve a significant increase in the probability or consequences of accidents previously considered and do not involve a signi ficant decrease in a safety margin, the amendments do not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) 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:
July 24, 1981