ML20111B178
| ML20111B178 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 04/30/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20111B170 | List: |
| References | |
| NUDOCS 9605140236 | |
| Download: ML20111B178 (3) | |
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UNITED STATES e
E NUCLEAR REGULATORY COMMISSION f
WASHINGTON, D.C. 20666-0001
.....,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0. 110 TO FACILITY OPERATING LICENSE NO. NPF-30 UNION ELECTRIC COMPANY CALLAWAY PLANT. UNIT 1 DOCKET NO. 50-483
1.0 INTRODUCTION
By letter dated February 9, 1996, Union Electric Company (UE), requested changes to the Technical Specifications (Appendix A to Facility Operating License No. NPF-30) for the Callaway Plant, Unit 1.
The proposed amendment would revise TS 5.3.1 to allow the use of ZIRL0 clad fuel rods and ZIRLO filler rods.
2.0 EVALUATION l
l The Westinghouse ZIRLO fuel is described in topical report WCAP-12610,
" VANTAGE + Fuel Assembly Reference Core Report." The VANTAGE + fuel assembly design was developed from the VANTAGE 5 fuel assembly design and was designed with ZIRLO, which is a new cladding and thimble tube alloy. The ZIRLO alloy i
is a zirconium alloy similar to Zircaloy-4 which was developed to enhance corrosion resistance. ZIRLO is a modification of Zircaloy-4 that includes a reduction in the tin and iron content, eliminating the chromium content, and adding one percent niobium.
l In addition to the use of ZIRLO alloy in VANTAGE +, dimensional modifications l
to the fuel assembly skeleton are introduced for extended-burnup applications.
The VANTAGE + reconstitutable top nozzle (RTN) has an option for a slight height reduction and a compensating recess in the adapter plate to accommodate the rod cluster control rod assembly hub in the fully inserted position for extended-burnup applications. The VANTAGE + RTN is otherwise identical to that i
l of the VANTAGE 5 design except for modifications necessary to accommodate extended burnup operations. These modifications consist of the use of ZIRLO guide thimbles and small skeletal dimensional alterations to provide additional fuel assembly and rod growth space for extended burnup levels.
Since the VANTAGE + fuel assembly is intended to replace either the Westinghouse Standard, Optimized, or VANTAGE 5 fuel designs, the VANTAGE +
assembly design envelope is equivalent to those of previous Westinghouse fuel assemblies. Also, the VANTAGE + fuel assembly is designed to be mechanically and hydraulically compatible with the previous Westinghouse fuel designs in full or transitional cores. The same functional requirements and design t
criteria established for the Westinghouse VANTAGE 5 fuel assembly remain valid 4
9605140236 960430 PDR ADOCK 05000483 P
.. for the VANTAGE + fuel assembly. The NRC staff approved the ZIRLO fuel design discussed in WCAP-12610 in a safety evaluation dated July 1, 1991.
The NRC staff also approved loss-of-coolant accident (LOCA) methodologies in a safety evaluation dated October 9,1991, for Westinghouse topical report WCAP-12610, Appendix F, "LOCA NOTRUMP Evaluation Model: ZIRLO Modifications," and Appendix G, "LOCA Plant Specific Accident Evaluation." Westinghouse performed the LOCA analyses assuming a total peaking factor of 2.45 at 102 percent of a core power of 2775 MWt. An appropriate set of input conditions and a worst break, a double-ended cold leg guillotine break with a discharge coefficient of 0.4, were used. Using the Westinghouse approved evaluation model, with modifications to account for the ZIRLO material properties, the calculated peak cladding temperature was 2083.5 degrees F, the calculated maximum local metal-water reaction was 7.2 percent, and the calculated total core-wide metal-water reaction was less than 0.3 percent. These values are below the allowable limits specified in 10 CFR 50.46(b) of 2200 degrees F,17 percent, and 1 percent, respectively. The analyses also indicated that the temperature transient would be terminated while the core geometry was still amenable to coeling in accordance with 10 CFR 50.46(b)(4).
Individual plant approved emergency core cooling system design assures long term cooling capability to satisfy 10 CFR 50.46(b)(5).
Based on the above, the staff finds the proposed changes to the Callaway TS to allow the use of ZlRLO clad fuel rods and ZIRLO filler rods acceptable.
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3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Missouri State official was notified of the proposed issuance of the amendment.
The State official had no comments.
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4.0 ENVIRONMENTAL CONSIDERATION
i The amendment changes a requirement with respect to the installation or use of i
a facility component located within the restricted area as defined in 10 CFR j
Part 20. The NRC staff has determined that the amendment involves no I
significant increase in the amounts, and no significant change in the types, l
of any effluents that may be released offsite, and that there is no j
significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the j
amendment involves no significant hazards consideration, and there has been no public comment on such finding (61 FR 7558). 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 issuance of 3
the amendment.
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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 be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
K. Thomas Date:
April 30,1996 l
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