ML20140D114
| ML20140D114 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 01/24/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20140D105 | List: |
| References | |
| NUDOCS 8601290145 | |
| Download: ML20140D114 (5) | |
Text
I q.R *t Gy UNITED STATES NUCLEAR REGULATORY COMMISSION n
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT N0.12 TO OPERATING LICENSE NO. NPF-30 UNION ELECTRIC COMPANY CALLAWAY PLANT, UNIT 1 DOCKET NO.
50-483
1.0 INTRODUCTION
By letter dated October 15, 1985, as supplemented by letter dated December 23, 1985, Union Electric Company (the licensee) requested an amendment to Facility Operating License No. NPF-30 for operation of the Callaway Plant in Callaway County, Missouri.
The amendment approves modifications to Pages 3/4 9-16, 5-6 and 5-7, and the amendment approves deletion of Page 5-8 of the Callaway Technical Specifications (TS). The amendment increases the permitted enrichment for storage in the Callaway Plant, Unit I spent fuel storage pool from the current value of 3.5 weight percent (w/o) U-235 to 4.2 w/o. This permits extended cycle operation in the Callaway plant and results in larger discharge fuel burnups. Therefore, the curve of ac'ceptable burnup as a function of initial enrichment (Figure 5.6-1 in the present Technical Specifications) is extended. This figure is also amended to include a separate curve for the optimized fuel assembly.
The Callaway plant has a two region spent fuel pool.
Region one is designed to contain fresh fuel and has a sufficient number of storage locations to accommodate a full core unloading. Region 2 contains a i
large number of storage locations but will safely store only fuel that has achieved a certain minimum burnup. The previous limits on storage are 3.5 weight percent (w/o) U-235 enrichment in Region 1 and an initial enrichment dependent burnup limit in Region 2 which has a minimum value of 29000 MWD /T at 3.5 w/o enrichment.
These values are obtained under the assumption of Westinghouse standard fuel assemblies.
The licensee wishes to reload the Callaway plant with Westinghouse Optimized Fuel Assemblies (OFA) having a maximum enrichment of 4.2 w/o U-235 in order to permit an 18 month cycle length fuel management l
plan. The spent fuel rack criticality analysis was redone to confirm that the criterion on rack k-effective could still be met.
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2.0 EVALUATION A.
Criticality Considerations The calculational methods and procedures used to perform the analyses are the same as those used in the prior analyses as described in the Callaway FSAR (Docket No. 50-483, Section 9.1.2).
Those methods and procedures were found to be acceptable for the original analysis and l
I remain so.
The center-to-center spacing between the boxes in the original analysis i
was assumed to be 9.14 inches. The "as-built" racks had a value of 9.24 i
for this dimension.
In Region 1 fuel is stored in every other box in a checkerboard design and three out of every four boxes are filled in Region 2.
These values meet our acceptance criterion of 0.95 for this j
quantity and are acceptable.
}
Calculational biases and uncertainties were obtained in the same manner as those of the original analyses. These were combined and added to the i
nominal k-effective value to obtain the value to be compared to the acceptance criterion. The results were 0.939 for Region 1 and 0.915 l
for Region 2.
These vahes meet our acceptance criterion of 0.95 for l
this quantity and are acceptable.
A curve of minimum enrichment as a function of critical enrichment was developed using the target value of 0.915. Separate curves were developed
'i fo'r 0FA and standard fuel. This is the same procedure employed for the original analysis and is acceptable.
We conclude that the criticality analysis for the storage of 4.2 weight l
percent U-235 enrichment ste dard as well as 0FA Westinghouse fuel in the i
Callaway racks is acceptable. This conclusion is based on the following:
1.
Previously approved methods and procedures were employed in j
the analysis 2.
Appropriate input assumptions are made and proper account is taken of biases and uncertainties.
3.
The results meet our criterion for k-effective of the racks.
B.
Other Considerations i
The increase in enrichment and consequent increase in discharge burnup as well as the use of 0FA fuel has certain consequences for the thermal-hydraulic, seismic and radiation aspects of the rack design. These are I
discussed below.
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The increased discharge burnup implies an increased heat load on the spent fuel pool cooling system. The pool temperature resulting from a refueling off-load and from an off-load plus full core disch'rge have been recal-culated by the licensee. The pool temperature' criterion was met in both cases. Audit calculations by the staff confirm these results. We conclude that the increase in enrichment is acceptable from a thermal-hydraulic standpoint.
The effect of the OFA fuel on the seismic apalysis of the pool was analyzed by the licensee. The lower weight of the OFA fuel when compared to standard fuel ensures that the original analysis is conservative. We find this to be acceptable.
The effect of the increased discharge burnup and switch to 0FA fuel on the dose calculations was analyzed. The methods and procedures that were used in the original analyses were employed and the results were within the acceptance criterion. Because acceptable results were obtained from pre-viously used and approved methods we find the dose results to be acceptable.
In summary, we conclude that the use of 0FA fuel and fuel of up to 4.2 w/o U-235 enrichment in the Callaway Spent Fuel Pool is acceptable.
C.
Technical Specification Cha'nges Figure 3.9-1 of Technical Specification 3/4.9.12 is altered to account for the revised analyses and to include a curve for 0FA fuel. The revised curves are consistent with the analyses and are acceptable. Specification 5.3.1 is revised to increase the permitted enrichment in the core to 4.2 w/o U-235. This is consistent with the limit for the spent fuel pool and is acceptable.
Specification 5.6.1.1 is altered to delete Figure 5.6-1 (identical to Figure 3.9-1) and to change the figure reference to 3.9-1.
In addition the enrich-ment designation is increased to 4.2 w/o U-235 and the storage location center-to-center spacing is increased to 9.24 inches. These changes are consistent with the spent fuel pool criticality analysis and are acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change in the installation or use of facility component located within the restricted area as defined in 10 CFR Part 20.
The staff has determined that the amendment involves no significant change in the types or significant increase in the amounts of any effluents that may be released offsite and that there is no significant increase in indi-vidual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no sig-nificant hazards consideration and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
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Pursuant to 10 CFR 51.22(b), no environmental impact statement or environ-mental assessment need be prepared in connection with the issuance of this amendment.
4.0 CONCLUSION
The Connission made a proposed determination that the amendment involves no significant hazards consideration which was published in the Federal Register (50 FR 46218) on November 6, 1985, as corrected in (50 FR 49468) on December 2,1985, and consulted with the state of Missouri.
No public comments were received, and the state of Missouri did not have any comments.
We have 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, and (2) 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 and safety of the public.
Principal Contributors:
W. L. Brooks, RSB T. W. Alexion, PWR#4 Dated: January 24, 1986 O
January 24, 1986 Amendment %. 12 DISTRIBUTION
- Docket' File @
NRC PDR Local PDR NSIC PWR#4 R/F HThompson MDuncan TAlexion P0'Connor OELD LHarmon EJordan BGrimes JPartlow TBarnhart (4)
WJones ACRS (10)
OPA LFMB s