ML13316B021
| ML13316B021 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 06/09/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML13316B018 | List: |
| References | |
| TAC-65271, NUDOCS 8806210384 | |
| Download: ML13316B021 (3) | |
Text
0 UNITED STATES 0
NUCLEAR REGULATORY COMMISSION 00 WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 103 TO PROVISIONAL OPERATING LICENSE DPR-13 SOUTHERN CALIFORNIA EDISON COMPANY SAN ONOFRE NUCLEAR GENERATING STATION, UNIT NO. 1 DOCKET NO. 50-206
1.0 INTRODUCTION
By letters dated October 17, 1985 and April 28, 1987, the Southern California Edison Company, the licensee for the San Onofre Unit 1 submitted a Technical Specification change request (Ref. 1 & 2).
The proposed change will require operation of all three reactor coolant loops for Mode 3 operation when the trip breakers are closed.
The existing San Onofre Unit 1 Technical Specifications permit plant operation in Mode 3 with only one reactor coolant loop (pump) in operation.
However, a Westinghouse reanalysis of the control rod bank withdrawal accident (from subcritical) concluded that the DNB design basis may not be met when only one pump is in operation (Ref. 3).
Thus, the safety margin as defined in the basis of the Technical Specification is reduced.
As soon as this situation became known the licensee adopted an interim position, where all three reactor pumps (loops) would be maintained in operation whenever the reactor trip breakers are in the closed position.
It should be noted that the potential for control rod motion out of the core is present only when the two reactor trip breakers connected in series with the gripper and lift coils of the control rod drive mechanisms are closed and the coils are energized. At the same time the licensee notified the NRC that a Technical Specification change would be submitted requiring operation of all three reactor coolant pumps in Mode 3, when the reactor trip breakers are closed (Ref. 2).
2.0 EVALUATION The proposed changes consist of the following:
- 1. Change to Technical Specification 3.1.2.C requiring operation of all three reactor coolant pumps (loops) in operational Modes 1 and 2 (as at present) but also in Mode 3 if the reactor trip breakers are closed. The exception to this requirement will be stated in Technical Specification 3.1.2.D.
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- 2. A change to Technical Specification 3.1.2.E making plant operation in Mode 3 with one reactor coolant loop in operation conditional on both reactor trip breakers being open.
- 3. Changes to the basis of Technical Specification 3.1.2 to provide the basis for the requirements stated above and the necessary editorial improvements.
- 4. Changes to item 15 in Table 4.1.2 reflecting the new requirements in the Technical Specification.
The proposed changes are reasonable and necessary in view of the results of the analyses performed by Westinghouse; and they are adequate for assuring required safety margins. Similar Technical Specification changes have been approved for many other plants. We conclude that the proposed changes are necessary and acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves changes in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part
- 20. The 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 this amend ment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact state ment or environmental assessment need be prepared in connection with the issuance of this amendment.
4.0 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, (2) such activities will be conducted in compliance with the Commission's regulations and (3) the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
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5.0 REFERENCES
- 1. Letter from K. P. Baskin, Southern California Edison Company to USNRC, dated April 28, 1987.
- 2. Letter from M. 0. Medford, Southern California Edison Company, dated October 17, 1985.
- 3. Letter from E. P. Rahe, Westinghouse Electric Corporation to D. Eisenhut, NRC, dated July 9. 1984 (MS-7A-84-003).
Principal Contributors: L. Lois Dated: June 9, 1988