ML20077A088
| ML20077A088 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 05/01/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20077A087 | List: |
| References | |
| NUDOCS 9105080261 | |
| Download: ML20077A088 (2) | |
Text
_ _ _ _ _ _ _ _ _ _ _ _ _ - - - _. _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
p aso f
w%,
c
- ! j, g., /,
UNr?ED STATES
?i NUCLEAR REGULATORY COMMISSION I c'd
'o WASHINGTON. D C. 20%6
%f + n,,,$
- ...+
SAFETY EVALUATION.BY.THE.0FFICE OF NUCLEAR REACTOR REGULATION FIL ATED.TO ARENDMENT NO. 98 TO.FACillTY 0PERATING. LICENSE.NO, NPF.17 50bTH CAROL INA EL ECTRIC A_ GAS. COMPANY SOUTH 4 A_ROL IN A_ PUBL IC-SERVICE AUTHORITY VIRGIL C.,50MMER WUCL EAR. STATION,. UNIT.NO, -1
_ DOCKET.NO. 50 395 1.0_ INTRODUCTION By letter dLted November 26, 1990 South Carolina Electric & Gas Company s'the licensee) submitted a request for a change to the Virgil C. Summer Nuclear Station, Unit No. 1 (Summer Station), Technical Specifications (TS).
The reouested change would remove surveillance requirement (SR) 4.8.1.1.1.b regarding the transfer of Class IE power supply from its normal to alternate offsite source.
In addition, the licensee has proposed editorial changes to TS 3.8.1.1.1 reflecting the deletion of the SR.
2.0 EVALUATION SR 4.8.1.1.1.b requires the licensee to demonstrate the operability of redundant offsite power sources for the Class IE buses by switching each bus from its normal to its alternate power supply once every 18 months.
This SR is not necessary for the reasons discussed below.
Two separate and physically independent offsite sources provide power to the Class IE buses at Sumer Station.
One source, the 230KV transmission line, normally supplies power to bus B through an Engineered Safety feature (ESF) transformer while the second *,ource, the 115KV line from Parr generating station, provides power to bus A through an emergency auxiliary transformer.
Either independent source can be lined up to power both Class IE buses by manually switching the breakers connecting the buses to the transmission lines.
The two independent power sources are continuously connected to their designated buses.
In the event of a loss of one of the offsite power sources, the diesel generator for the affected Class 1E bus will automatically start and, once the bus is isolated, it will supply power to that bus.
9105080261 910501 DR ADOCK 0500 S
1 j
~
l 2
Since there are two independent offsite sources continuously supplying power to their designated buses through their respective trensformers; and since in the event of a loss of one of the offsite power sources, the appropriate diesel will supply power to the affected bus, the staff concludes that the ability to connect the safety buses to a single offsite power source is intended as a maintenance feature to allow for servicing of the breakers, not as an operational feature.
Since it is not an operational feature, it does not meet the definition of an " alternate" offsite power supply; therefore, the requirement to transfer the onsite Class 1E power supply from its normal to its alternate source is not applicable to Summer Station.
The staff has determined, therefore, that the proposal to remove SR 4.8.1.1.1.b and the editorial changes associated with its removal are acceptable.
3.0 LTATE CONSULTATIO_N In accordance with the Commission's regulations, the South Carolina State official was notified of the proposed issuance of the amendment.
The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements.
The NRC staff has determined that the amendment involves 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 Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration and therc has been no public comment on such finding (56 FR 897). AccordIngly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10CFR51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
The Commission has 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,.
(2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor
- 0. Chopra Date: April 29, 1991
.