ML19320B397
| ML19320B397 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 06/06/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19320B394 | List: |
| References | |
| NUDOCS 8007100307 | |
| Download: ML19320B397 (3) | |
Text
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NUCLEAR REGULATORY COMMISSION
- A CSCv/
E WASHINGTO N, D. C. 2C355 SAFETY EVALUATION BY THE OFFICE OF N" CLEAR REACTCR REGULATION SUPPORTIt;G AMEND :Etti N0. 57 TO LICEt SE NO. DPR-20 CONSUMERS POWER C0:<PANY PALISADES PLANT DOCKET T10. 50-255
1.0 INTRODUCTION
AND DISCUSSION By letter dated February 26,1980, (Reference 1), Consumer's Pcwer Corpany (CPCo) (the licensee) requested an amendment to Appendix A of Prcvisicnal Operating License No. DPR-20 for the Palisades Plant.
A continuing investi-gation of the water hole peaking issue presented in MRC letter dated July 11,1979 (Reference 2) resulted in the need to add an additional radial peaking factor into the Palisades Plant Technical Specifications.
A problem was identified by CPCo in their Technical Specifications " Basis" Section with regard to peaking f actors and their treatment.
The current Technical Specifications state that the limitations on Fr^ (assembly radial peaking f actor) and FrT (total radial peaking factor) ensure that the assumptions used in the DNB analysis remain valid.
According to the licensee, it has been determined through an inspection of a quarter ccre, pin by pin power distribution calculation and comparison against assurptions in the DNB analysis that an additional peakir.g f actor limit is needed.
2.0 EVALUATION Analysis of the Palisades Plant lattice indicated that an intericr fuel pin is most limiting with respect to DNB even though it may not be the peak power pin.
Inherent in the derivation of limits based on the DN3 analysis was the assumption that, for assemblies approaching thermal limits, the ratio of t? limiting DNB pin power to the peak pin power would not exceed that oe in the analysis.
The licensee has stated that an inspection of Cycle 4 physics calculations has shown this assumption to be invalid.
Although, according to CPCo, no interior fuel pin is expected to exceed the pin power (radial x local) assumed fcr the Cycle 4 DNB analysis, it is possible to have relatively high power assemblies that also have high interior peaking factors.
Based on the above, the licensee considers it appropriate to impcse a limit on the product of radial peaking factor times interior pin local peaking f actor to assure that the assumptions in the DNB analysis remain valid in all cases.
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2 According to the licensee, an extensive analysis of Cycle 4 assembly pcwer distribution has shewn that OfiB marg 1ns are adequately maintained if the highest interior rod radial peaking f actor is limited to that assumed in the crgintal Of;B analysis of G relcad fuel. This value is the local peaking f actor fcr the MDfiBR pin from Figure 6.2 of Reference 3 times that : aximum assembly radial peaking f actor (1.145 X 1.45 = 1.66).
The licensee asserts that since the limit on peak LHGR provides protection against Drib, a limit on the interior fuel rod LHGR is proposed.
This limit maintains the axial peaking restrictions derived in previous analysis and is computed by multiplying the overall limit on LHGR by the ratio of the interior rod radial g/Fr{ng factor limit over the eak total radial peaking factor limit (Fr
).
Based on the considerations discussed above, we have concluded that the results of the analysis are acceptable and the addition of the interior fuel rod peaking f actor limit will maintain the safety margin which forms the basis for the Technical Specifications.
We, therefore, find the proposed changes acceptable.
3.C Ef;VIR0fEEf;TAL CONSIDERATION We have determined that the amendment does not authorize a change in ef fluent 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 statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
4.0 CONCLUSION
We have concluded, based on the consideration 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 Cormission's regulations and the issuance of this amendment will not be inimical to the cormon defense and security or to the health and safety of the public.
Cate:
June 6, 1980
u
. References 1.
Letter, David P. Hoffman (CPCo) to Directer, NRC (Attn:
D. L. Ziemann),
Dated February 26, 1980.
2.
Letter, D. L. Ziemann (';RC) to D. A. Bixel (CPCo), dated July 11, 1979.
3.
Palisades Plant, Cycle 3 Reload Analysis, XN-NF-77-59, Exxo1 Nuclear Cornpany, Inc., Richland, Washington, dated December,1977.
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