ML20002C688
| ML20002C688 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 12/18/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20002C685 | List: |
| References | |
| NUDOCS 8101100727 | |
| Download: ML20002C688 (4) | |
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UNITED STATES fi
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NUCLEAR REGULATORY COMMISSION J
f WASHINGTON, D. C. 20555 j
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4 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT N0.
61 TO FACILITY OPERATING LICENSE N0. OPR-28 VERMONT YANKEE NUCLEAR POWER CORPORATION i
VERMONT YANKEE NUCLEAR POWER STATION DOCKET NO. 50-271 1
1.0 ptroduction Vermont Yankee Nuclear Power Corporation (VYNPC or licensee) has proposed changes to the Technical Specifications of the Vermont Yankee Nuclear Power Station (VY) in Reference 1 and as supplemented by Reference 2.
The proposed changes relate to the core for Cycle 8 operation at power levels up to 1593 MWt (100'.' power).
In support of the reload application, the licensee has enclosed proposed Technical Specification changes in Reference 1 and the GE BWR supplemental licensing submittal (Reference 3).
This reload involves loading of prepressurized GE 8x8 retrofit (P8x8R) fuel. This is the same type of fuel as was loaded during the last reload.
The description of the nuclear and mechanical designs of 8x8 retrofit is contained in References 4 and 5.
Reference 4 also contains a complete set of references to topical reports which describe GE's analytical methods for nuclear, thermal-hydraulic, transient and accident calculations, and information regarding the applicability of these methods to cores containing a mixture of 8x8 and 8x8R fuel. The use and safety implications of prepressurized fuel are presented in Appendix D to Reference 3 and have been found acceptable' per Reference 5.
The conclusions of Reference 6 found that the methods of Reference 4 were generally applicable to prepressurized fuel. Therefore, unless other-wise specified, Reference 4, as supported by Reference 6, is adequate justification for the current application of prepressurized fuel. This report also addresses proposed Technical Specification changes submitted by VYNPC at the request of the NRC staff in Reference 7.
2.0 Evaluation 2.1 Reactor Physics i
The reload application follows the procedure described in NEDE-240ll-P,
" Generic Reload Fuel Application." We have reviewed this application and the consequent Technical Specification changes. The transient analysis input parameters are typical for BWRs and are acceptable. Core wide transient analysis results are given for the limiting transients and the required operating limit values for MCPR are given for each fuel type. The revised MCPR limits are the only changes in Technical Specifications required by the reload and they are acceptable.
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Other changes in the Technical Specifications include a change in the allowable delay time in the protection system from 100 milliseconds to 50 milliseconds to carrespond to the value used in the licensing analyses, a change in the maximum total peaking factor Technical Specification to reflect the presence of fuels of different designs (number of rods per bundle and fuel length) in the core, and a change in the control rod pattern and sequence requirement to reflect the revised analysis procedure of NEDE-240ll-P-A.
We have reviewed these changes and conclude that they are acceptable.
1 2.2 Thermal Hydraulics As stated in Reference 4, for BWR cores which reload with GE's retrofit 8x8R fuel, the safety limit minimum critical power ratio (SLMCPR) resulting from either cere-wide or localized abnormal operational transients is equal 1
to 1.07.
When meeting this SLMCPR during a transient, at least 99.9% of the fuel rods in the core are expected to avoid boiling transition.
To assure that the fuel cladding integrity SLMCPR will not be violated during any abnormal operational transient or fuel misloading, the most limiting events have been reanalyzed for this reload by the licensee, in order to detennine which event results in the largest reduction in the minimum critical power ratio. These events have been analyzed for the exposed 8x8 fuel and the exposed and fresh 8x8R fuel. Addition of the largest reductions in critical pcwer ratio to the SLMCPR was used to establish the operating limits for each fuel type.
We have found the methods used for this analysis consistent with previously approved past practice (Reference 4). We have found the results of this analysis and the corresponding Technical Specification changes acceptable.
2.3 Administrative Changes The change in the definition of " operable" proposed by the licensee is in response to a request from the NRC staff (Reference 7). This change improves the enforceability of Technical Specifications, and is acceptable. Also typographical corrections have been made on pages 136 and 179.
3.0 Environmental Considerations We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact, and pursuant to 10 CFR Section 51.5(d)(4) that an environmental impact statement, or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of the amendment.
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. 4.0 Conclusion We have concluded, based on the considerations discussed above, that: (1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the cormion defense and security or to the health and safety of the public.
Dated:
December 18, 1980
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j REFERENCES i
l.
Letter, L.H. Heider (VYNPC) to Office of Nuclear Reactor Regulation j
(USNRC), dated August 19, 1980.
2.
Letter, L.H. Heider (VYNPC) to Office of Nuclear Reactor Regulation (USNRC),datedOctober7,1980 i
3.
" Supplemental Reload Licensing Submittal for Vermont Yankee Nuclear Power j
Station Reload 7" Y1003J01A02, July 1980.
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4.
" General Electric Boiling Water Reactor Generic Reload Application,"
i NEDE-24011-P-A, May 1977.
I 5.
Letter, R.E. Engel (GE) to U.S. Nuclear Regulatory Comission, dated January 30, 1979.
6.
Letter, T.A. Ippolito (USNRC) to R. Gridley (GE), Arril 16, 1979, and i
enclosed SER.
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7.
Letter, D. Eisenhut (USNRC) to L.H. Heider (VYNPC), April 10, 1980.
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