ML17311A394
| ML17311A394 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 11/03/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17311A393 | List: |
| References | |
| NUDOCS 9411140020 | |
| Download: ML17311A394 (6) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001
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P'DR Q SAFETY EVALUATION'YTHE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 86 TO 'FACILITY OPERATING LICENSE NO. NPF-41 AMENDMENT NO.
74 TO FACILITY OPERATING LICENSE NO.
NPF-51'ND AMENDMENT NO. 58 TO FACILITY OPERATING LICENSE NO. NPF-74 ARIZONA PUBLIC SERVICE COMPANY ET AL.
PALO VERDE NUCLEAR GENERATING STATION UNIT NOS.
1 2
AND 3 DOCKET NOS.
STN 50-528 STN 50-529 AND STN 50-530 1..0 INTRODUCTION'y letter dated January 4,
1994, the Arizona Public Service Company (APS or the licensee) submitted a request for changes to the Technical Specifications (TS) for the Palo Verde Nuclear 'Generating Station, Units 1, 2, and, 3 (Appendix A to Facility Operating License Nos.
and NPF-74, respectively).
The Arizona Public Service Company submitted this request on behalf of itself, the Salt River Project Agricultural Improvement and Power District, Southern California Edison
- Company, El Paso Electric Company,. Public Service Company of New Mexico, Los Angeles Department of Water and Power, and Southern California Public Power Authority.
The current TS 3.2.3, "Azimuthal Power Tilt," requires that the actual tilt be less than or equal to the tilt allowance used in the core protection calculators (CPCs).
Additionally, til.t shall be no greater than the limit specified, in the Core Operating Limits Report (COLR) with the core operating limits supervisory system (COLSS) in
- service, or no greater than 10 percent with the COLSS out of service.
The proposed changes would revise the azimuthal power tilt limit from less than or equal to 10 percent to less than or equal to 3 percent'hen the COLSS is out of service.
- 2. 0 EVALUATION The limitations on the azimuthal power tilt ensure that deign safety margins are maintained by limiting the core power distribution to the initial values assumed in the accident analyses.
The maximum tilt is a key initial safety parameter in the analysis of single control element.assembly (CEA) movement events such as the CEA ejection or CEA drop.
The plant safety analysis assumes a tilt of no-greater than 10 percent when the COLSS is in service and no greater than 3 percent when COLSS is out of service.
However, the current specification allows the maximum tilt to equal 10 percent above 20 percent of rated thermal power with COLSS out of service as long as it does not exceed the allowance used in the CPCs.
Since this is
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nonconservative with respect to the initial tilt value used in the analysis of single CEA movement events when COLSS is out of service, the proposed change would place a 3 percent limit on the maximum azimuthal tilt during normal steady-state operation when COLSS is out of service.
This is acceptable as it would make the TS consistent with the safety analyses.
Additionally, the corresponding changes to the Bases are consistent with these TS changes and are, therefore, acceptable.
This discrepancy between the safety analyses and the TS has existed since Cycle 1.
Therefore, the licensee has evaluated previous operation and has concluded that, in previous instances when the COLSS was out of service and the azimuthal tilt was greater than 3 percent, there existed sufficient margin to the linear heat rate and departure from nucleate, boiling ratio TS limiting conditions for operation to assure that no fuel failures occurred.
Currently, administrative controls are in place to assure compliance with this requirement.
The staff finds this to be acceptable until, this revised TS is implemented.
It should be noted that the current plant safety analyses, in which the COLSS is in service, but both control element assembly calculators (CEACs) are inoperable, also assume that the azimuthal tilt is no greater than 3 percent.
Since TS 3.2.3 only addresses COLSS in or out of service and not CEAC operability, the licensee has changed the appropriate procedures to require a
power reduction to less than 50 percent of rated thermal power in the event the tilt exceeds 3 percent when both CEACs are inoperable.
For future cycles, the case of CEACs inoperable will be analyzed with the full tilt allowed by the COLSS in-service limit (i.e.,
10 percent) as specified in the COLR.
The staff has reviewed the proposed changes to TS 3.2.3 and, based on the above evaluation, finds them acceptable for operation of Palo Verde Nuclear Generating Station, Units 1, 2, and 3.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Arizona State official was notified of the proposed issuance of the amendments.
The State official had no comments.
- 4. 0 ENVIRONMENTAL CONSIDERATION The amendments change a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The NRC staff has determined that the amendments involve 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 amendments involve no significant hazards consideration, and there has been no public comment on such finding (59 FR 22001).
Accordingly, the amendments meet 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 statement or
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environmental assessment need be prepared in connection with the issuance of, the amendments.
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'e conducted in compliance with the Commission's regulations, and (3),ihe issuance of the amendment will not 'be inimical to the. common defense and security or to the health and safety of the public.
Principal Contributors:
L. Kopp B. Holian Date:
November 3, 1994
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