ML13331B164
| ML13331B164 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/11/1989 |
| From: | Baskin K Southern California Edison Co |
| To: | NRC/IRM |
| Shared Package | |
| ML13331B165 | List: |
| References | |
| NUDOCS 8904170202 | |
| Download: ML13331B164 (2) | |
Text
Southern California Edison Company P.O. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 KENNETH P. BASKIN TELEPHONE VICE PRESIDENT 818-302-1401 April 11, 1989 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 Amendment Application No. 169 San Onofre Nuclear Generating Station Unit 1 Provided as an enclosure is Amendment Application No. 169 to Provisional Operating License No. DPR-13. Amendment Application No. 169 consists of Proposed Change No. 208 which requests revision of the Appendix A Technical Specifications.
Proposed Change No. 208 is a request to revise Technical Specification 3.5.1, Reactor Trip System Instrumentation. The revision will include a footnote on Mode 2 of the Applicable Modes column for Item 4, the Intermediate Range, Neutron Flux, in Table 3.5.1-1.
The footnote will indicate the startup rate circuit for the intermediate range channels will be enabled at 10-4% reactor power. This will reflect a modification to the startup rate circuit which moved it from 10-7% reactor power to 10-4% reactor power.
During the Cycle 10 refueling outage, the NIS was replaced. After the new NIS was installed, testing of the system indicated an unacceptable noise level, particularly in the lower power level of the intermediate range. This noise could potentially affect the intermediate range channels by causing spurious reactor trips during power ascension through the startup rate reactor trip.
Therefore, resolution of the problem was to move the startup rate circuit from 10-7% reactor power to 10-4% reactor power. This results in the startup rate reactor trip and startup rate rod stop being enabled at 10-4% reactor power.
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Document Control Desk
-2 Review of this issue by NRC Region V inspectors has resulted in a need to revise the technical specifications to indicate how the modification has affected the intermediate range startup rate circuit. This proposed change will resolve these concerns. The NRC staff has indicated that this change is considered to be a return to service issue requiring NRC approval prior to startup. Therefore, Amendment Application No. 169 is requested to be considered on an emergency basis in accordance with the provisions of 10CFR50.91(5). Presently, San Onofre Unit 1 is shutdown and startup is imminent. The NRC's normal review and approval schedule for an amendment application would significantly delay the plant's restart. These circumstances could not be avoided. Initially, it was SCE's intention to submit a technical specification change following the plant's return to service. This position was based on the Intermediate Range channels not being credited in any accident analyses. Further, the startup rate reactor trip and startup rate rod stop are fully capable of performing their intended function in Mode 2 when enabled at 10-4% reactor power. The NRC staff indicated that this design feature must be included in the technical specifications before startup from the present outage. Thus, it is necessary to submit this change on an emergency basis.
We are concerned with the impact this proposed change will have on SCE's and the NRC's workload considering the remaining return to service technical specification changes under NRC staff review. We will continue to work closely with the NRC staff on this and the remaining restart issues such that the schedule for the unit's return to service is not significantly impacted.
If you have any questions regarding this matter, please contact us as soon as possible.
Very truly yours, Enclosures cc: 3. B. Martin, Regional Administrator, NRC Region V F. R. Huey, NRC Senior Resident Inspector, San Onofre Units 1, 2 and 3
- 3. H. Hickman, California Department of Health Services