ML18025B704
| ML18025B704 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 12/29/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18025B703 | List: |
| References | |
| NUDOCS 8201210395 | |
| Download: ML18025B704 (6) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.
77 TO FACILITY LICENSE NO.
DPR-52 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT, UNIT NO.
2 DOCKET NO. 50-260 1.0 2.0 3.0 Introduction By letter dated September 9,
1981 (TVA BFNP TS 165b),
as supplemented by letter dated December 11, 1981, the Tennessee Valley Authority the licensee or TVA) requested changes to the Technical Specifications Appendix A) appended to Facility Operating License No.
DPR-52 for the Browns Ferry Nuc1ear Plant, Unit No. 2.
The proposed amendment and revised Technical Specifications would extend the exposure range of the Maximum Average Planar Linear Heat Generation Rate (MAPLHGR) versus average planar exposure limits from 30,000 MWd/T to 40,000 MWd/T for the 8 x 8 fuel assemblies in the core.
Discussion Basically, MAPLHGR limits are imposed to restrict the amount of stored energy in the fuel to limit the amount of cladding heatup in the event of a Loss of Coolant Accident (LOCA).
The specific requirement in 10 CFR 50, Appendix K, is that the peak cladding temperature (PCT) following the postulated design basis loss-of-coolant accident not exceed 2200oF.
To support the extension of the MAPLHGR limits, TVA submitted a revision (No. 3) to NED0-24088-1, "LOCA Analysis for Browns Ferry Nuclear Plant Unit 2 dated May 1981 prepared by the General Electric Company (GE).
Evaluation On October 6, 1980, we issued Amendment No.
57 to Facility Operating License No.
DPR-52 which extended the MAPLHGR limits for the 7.x 7 fuel elements in the Unit 2 core from 30,000 to 40',000 MWd/T.
The safety evaluation supporting this amendment described the considerations. relating to MAPLHGR limits and the basis for the staff's conclusion that extension of the MAPLHGR limits for 7 x 7 fuel was acceptable.
The safety evaluation:
supporting Amendment No.
57 is incorporated herein by reference.
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On behalf of the licensee, GE has re-evaluated the adequacy of the Unit 2 ECCS systems for 8 x 8 fuel (the core now contains a mixture of 7 x 7, 8 x 8, 8 x 8R and P8 x 8R) at exposures out to 40,000 MWd/T.
The supplemental analysis was performed using analytical procedures previously approved by the staff.
Additionally, these methods are applicable for an average planar exposure of 40,000 MWd/T.
The analysis results show that with MAPLHGRs limited to the values in Tables 3.5. I-1 thru 3.5. I-5 of the proposed Technical Specifications, the cladding temperature and local cladding oxidation are well below the 2200oF PCT and 17/ local cladding oxidation limits in 10 CFR 50.46.
As can be noted, the MAPLHGR limits being added for fuel exposures of 35,000 and 40,000 MWd/t are approximately 10Ã lower than the limits during the first 30,000 MWd/t of exposure for each fuel type.
The calculated PCTs that the fuel might reach in a postulated uncovery accident are also lower by about 200'F during the last 10,000 MWd/t of exposure com-pared to when the fuel is fresh (i.e., during the first 20,000 MWd/t of exposure).
For each of the Bx8 fuel types, the calculated oxidation fraction at 35,000 and 40,000 Mwd/t of exposure is 0.001 in all cases vs.
0.003 or 0.004 when the fuel is fresh.
Thus, at the proposed extended exposures, the margin between the acceptable thermal hydraulic limits and the calculated maximum operating limits wi'll be increased compared to operation during the first 30,000 MWd/t of exposure.
Since Amendment No.
57 was issued, GE had proposed by letters dated May 6, 1981 and May 28, 1981 from R.
E.
Engel (GE) to T. A. Ippolito (NRC) that credit for approved ECCS evaluation model changes be applied to offset MAPLHGR penalties we had proposed to account for possible high burnup fission gas release.
GE's proposal was found con-ditionally acceptable, and by letter dated December ll, 1981, TVA in-formed us that the requi red conditions are applicable to Browns Ferry Unit Nos.
1, 2 and 3.
We conclude that the proposed changes to the Technical Specification to extend the MAPLHGR limits to a burnup of 40,000 MWd/T are acceptable.
4.0 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 51.5(d)(4), that an environmental impact state-ment or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
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5.0 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 common defense and security or to the health of the public.
Dated:
December 29, 1981
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