ML20206P887
| ML20206P887 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 05/14/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20206P883 | List: |
| References | |
| NUDOCS 9905190007 | |
| Download: ML20206P887 (4) | |
Text
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UNITED STATES g
j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20066-0001 gs,...../
I SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED AMENDMENT NO. 97 TO FACILITY OPERATING LICENSE NO. NPF-85 PECO ENERGY COMPANY
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LIMERICK GENERATING STATION. UNIT 2 DOCKET NO. 50-353
1.0 INTRODUCTION
By letter dated March 11,1999 (Ref.1), as supplemented by letter dated April 21,1999 (Ref. 3), PECO Energy Company (the licensee), submitted a request to amend the Technical Specifications (TS) for the Limerick Generating Station, Unit 2 (Limerick Unit 2). The proposed TS amendment reflects changes to the Minimum Critical Power Ratio (MCPR) Safety Limit due to the use of cycle-specific analyses performed by General Electric Nuclear Energy (GENE) for Limerick Unit 2 Cycle 6. The Limerick Unit 2 Cycle 6 core is a mixed core with GE11, GE13, and Ex-Shoreham GE6 (reused channels) fuel bundles. The April 21,1999, letter provided clarifying information that did not change the initial no significant hazards consideration determination.
2.0 DISCUSSION The licensee has requested TS changes for the Limerick Unit 2 Cycle 6 reload. The proposed changes involve TS 2.1, " Safety Limits," and the associated TS Bases. Safety limits are established to protect the integrity of the fuel cladding, reactor pressure vessel, and primary
. system piping during normal plant operations and anticipated transients. The fuel cladding integrity Safety Limit is the MCPR. The purpose of the MCPR Safety Limit is to ensure that
. greater than 99.9 percent of all fuel rods in the core avoid transition boiling if the limit is not violated.
The Limerick Unit 2 Cycle 6 MCPR Safety Limits were calculated using GESTAR-Il Rev.13, described in NEDE-24011-P-A-13 and Amendment 25 to NEDE-20411-P-A. Amendment 25 to GESTAR-Il provides the methodology for implementation of cycle-specific MCPR Safety Limits that replace the former generic bounding MCPR Safety Limits. By letter dated March 11,1999 (Ref. 2), the Nuclear Regulatory Commission (NRC) approved Amendment 25 to NEDE-20411-P-A for referencing in license applications. The staff's March 11,1999, evaluation concludes that the methodology described in Amendment 25 is acceptable for determining i
cycle-specific values for MCPR Safety Limits, l:
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2 The new MCPR Safety Limits for Limerick Unit 2 Cycle 6 were calculated based on cycle-specific inputs which include the following parameters: the actual core design; projected control blade pattems; the actual bundle parameters; and the full cycle exposure range. The MCPR Safety Limits for Cycle 6 were determined to be 1.12 for operation with two recirculation loops and 1.14 for single loop operation.
The Limerick Unit 2 Cycle 6 analysis using cycle-specific inputs in conjunction with the approved method is acceptable. The Cycle 6 MCPR Safety Limit will ensure that 99.9 percent of the fuel rods in the core will not experience boiling transition which satisfies the requirements of General Design Criterion 10 of Appendix A to 10 CFR Part 50 regarding acceptable fuel design limits.
Therefore, the staff has concluded that the justification for determining the MCPR Safety Limit value of 1.12 for two loop operation and 1.14 for single loop operation using approved methodologies is acceptable.
3.0 TECHNICAL SPECIFICATION CHANGES The licensee has proposed to change TS 2.1.2, " Safety Limits - Thermal Power, High Pressure and Low Flow," and the supporting Baser section to reflect the new MCPR Safety Limits. The MCPR Safety Limit is changed from 1.11 to 1.12 for two recirculation loop operation and from 1.12 to 1.14 for single recirculation loop operation with the reactor vessel steam dome pressure greater than 785 psig and core flow greater than 10% of rated flow. The Bases section has also been revised to indicate that the above listed MCPR Safety Limits values are valid only for Cycle 6 operation. These changes are based en the results of cycle specific analyses performed using NRC-approved methodologies. These changes are acceptable.
4.0
SUMMARY
CONCLUSIONS The staff has reviewed the licensee's proposed TS changes relating to the MCPR. Based on the review, the staff concludes that the proposed TS changes are acceptable.
5.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Pennsylvania State official was notified of the proposed issuance of the amendment. The State official had no comments.
6.0 ENVIRONMENTAL CONSIDERATION
i Tlie amendment changes a requirement with respect to installation or use of a facility 1
component located within the restricted area as defined in 10 CFR Part 20. The NRC 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 the amendment involves no
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l significant hazards consideration, and there has been no public comment on such finding j
(64 FR 17028), Accordingly, the 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 statement or environmental assessment need be prepared in connection with the is.suance of the amendment.
7.0 CONCLUSION
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I 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 be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the e
common defense and security or to the health and safety of the public.
Principal Contributor: A.Cubbage
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Date: bby 14,1999 -
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8.0 REFERENCES
1.
Letter from Garrett D. Edwards, PECO Energy Company, to U.S. NRC, " Limerick Generating Station Unit 2, Technical Specification Change Request No. 98-07-2," dated March 11,1999.
2.
Letter from Frank Akstulewicz, NRC, to Glen A. Watford, " Acceptance for Referencing of Licensing Topical Reports NEDC-32601P, Methodology and Uncertainties for Safety Limit MCPR Evaluations; NEDC-32694P, Power Distribution Uncertainties for Safety Limit MCPR Evaluation; and Amendment 25 to NEDE-24011-P-A on Cycle-Specific 1
Safety Limit MCPR," dated March 11,1999.
i 3.
Letter from Garrett D. Edwards, PECO Energy Company, to U.S. NRC, " Limerick Generating Station Unit 2,- Technical Specification Change Request No. 98-07-2," dated April 21,1999.
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