ML20138E240
| ML20138E240 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 11/29/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20138E238 | List: |
| References | |
| NUDOCS 8512130376 | |
| Download: ML20138E240 (3) | |
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NUCLEAR REGULATORY COMMISSION g
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WASHINGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 3 TO FACILITY OPERATING LICENSE NO. OPR-80 DIABLO CANYON UNIT 1, DOCKET NO. 275; AND AMENDMENT NO. 1 TO FACILITY OPERATING LICENSE NO. DPR-82, DIABLO CANYON UNIT 2, DOCKET NO. 50-323 INTRODUCTION By letter dated September 6, 1985, (LAR 85-09) Pacific Gas and Electric Company (PG&E) requested changes to the Diablo Canyon Units 1 and 2 combined Technical Specification 3/4.2.1, " Axial Flux Difference". The changes would implement a Westinghouse developed power distribution control methodology called Relaxed Axial Offset Control (RA0C) for Diablo Canyon Unit 1 and would retain the existing Technical Specifications for Unit 2.
The changes require an amendment to the Technical Specifications for both Unit 1 and Unit 2.
EVALUATION Westinghouse reactors have for a number of years operated under a power distribution control system called Constant Axial Offset Control (CAOC),
which ensures peaking factors will remain below values assumed as input for accident analyses during normal operation of the power plant. Basically CA0C achieves its result by requiring plant operation within a 15% flux difference
( I) around a measured target value. By controlling the axial power distribution, the possible skewing of the axial xenon distribution is limited, thus minimizing xenon oscillations and their effects en the power distribution.
Plants have varying degrees of margin to the peaking factor limits which can be supported by CAOC. Westinghouse developed the RAOC to directly determine the allowed band of I operation required to support any plant specific peaking factor limit. The staff approved RAOC for referencing in-licensing actions in a letter from C. Thomas (NRC), to E. P. Rahe (W) " Acceptance for Referencing of Licensing Topical Report WCAP-10216(P) (NS-EPR-2649)," dated February 28, 1983.
8512130376 851129 PDR ADOCK 05000275 P
- The staff has reviewed the Technical Specification changes proposed by PG&E for Diablo Canyon Unit 1 and finds they correctly implement RA0C. Since this represents the application of an approved methodology, the proposed Technical Specification changes are acceptable. As described by PG&E, the analysis, which applies to Diablo Canyon Unit 1 is applicable only after the unit reaches 8000 MWD /MTU burnup in Cycle 1 and thereafter until the end of Cycle 1.
Specific evaluations for subsequent cycles must be made to determine if the allowable AI band curve remains valid or if further revisions are required by an additional Technical Specification change.
In addition to implementation of RAOC for Unit 1, the proposed changes also modify the existing Technical Specification 3/4.2.1 to remain applicable for Unit 2 only. This is an adminstrative change and is therefore acceptable also.
CONTACT WITH STATE OFFICIAL The NRC staff has advised the Chief of the Radiological Health Branch, State Department of Health Services, State of California, of the proposed determination of no significant hazards consideration.
No comments were received.
ENVIRONMENTAL CONSIDERATION These amendments invoive changes in operating administrative procedures. The staff has determined that the amendments do not involve any increase in the amounts of any effluents that may be released offsite and that there is no increase in the individual or cumulative occupation radiation exposure.
The Commission has previously issued proposed findings that the amendments involve no significant hazards consideration, and there has been no public comment on such findings. Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9) and (10).
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.
CONCLUSION Based upon its eveluation of the proposed changes to the Diablo Canyon Units 1 and 2 combined Technical Specifications, the staff has concluded 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 regulation, and (3) the issuance of these amendments will not be iminical to the common defense and security or the health and safety of the public.
Dated: MOV 20 B35
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November 29. 1985 DIABLO CANYON NUCLEAR ~ POWER PLANT - ISSUANCE OF AMENDMENT NO. 3 TO FACILITY OPERATING LICENSE N0. DPR-80 (UNIT 1) AND AMENDMENT N0. 1 TO FACILITY OPERATING LICENSE N0. DPR-82 (UNIT 2)
DISTRIBUTION EDocket:Fi,le=50_-275/3233 NRC PDR Local PDR PBD-7 Reading F. Miriglia F. Schroeder H. Schierling Attorney, OELD H. L. Thompson L. Harmon E. Jordan B. Grimes J. Partlow T. Barnhart (8)
'W. Jones W. Regan ACRS (10)
OPA LFMB