ML20147B712
| ML20147B712 | |
| Person / Time | |
|---|---|
| Site: | 07001308 |
| Issue date: | 11/17/1978 |
| From: | Empson F NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| NUDOCS 7812180015 | |
| Download: ML20147B712 (3) | |
Text
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,/ 43 UNITED STATES y* NUCLEAR REGULATORY COMMISSION g j WASHINGTON, D. C. 20555 h,....f W l 71978 Docket No. 70-1308 License SNM-1265 AmenCnent No. 6 NOTE T0: Files FROM: F. M. Empson Fuel Reprocessing and Recycle Branch
SUBJECT:
GENERAL ELECTRIC COMPANY - AMENDMENT OF MATERIALS LICENSE SNM-1265 TO PERMIT RECEIPT OF LACROSSE BOILING '.iATER REACTOR FUEL The General Electric Company has requested in a letter dated September 22, 1978 that Materials License SNM-1265 be amended to permit storage of BWR fuel assemblies from the Lacrosse Boiling Water Reactor.
Lacrosse BWR assemblies are somewhat different in geometry and enrich-ment from the BWR assemblies previously licensed for storage at the Morris Operation.
General Electric has not previously stored Lacrosse fuel. However, they have agreed to accept the fuel to make it possible for Dairyland to increase capacity in the spent fuel pool at Lacrosse. It is antici-pated that the fuel will be returned to Lacrosse following completion j of the rerack modification.
General Electric requests that License SNM-1265, section 6-A and conditions 14 and 16 be amended in the following way. Added statements in the license are italicized.
6-A. - Fuel assemblies from reactors using natural water i for cooling and enriched not greater than 5 percent U-235 with a maximum reactivity not to exceed k. (cold) of 1.40 for 7x7 or 8x8 BWR fuel bundles, 1.3B for 10x20 BUR fuel bundles (<5.65 inches square),1.37 for 15x15 PWR fuel bundles (<8.55 inches square), and 1.41 for 14x14 PWR fuel bundles (<7.80 inches square). These fuels will possibly contain:
- 1. Uranium 235
- 2. Plutonium
- 3. Fission Products 7CHW C 1218() g 5o468 $
Il0V 171978 Files 14. - Fuel to be stored shall meet km limits of 1.40 for 7x7 or 8x8 BWR fuel,1.38 for 10x10 BWR fuel (<5.65 inches square),1.37 for 15x15 PWR fuel (<8.55 inches square) and 1,41 for 14x14 PWR fuel (<7.80 inches square) without allowance for.burnup.
- 16. - Fuel stored shall be limited to that notexceeding the maximum enrichments, and range of other parameters shown in Figures A.ll-1 and A.ll .2 of NED0-21326, with the follotting exception: the licensee is authorized to store stainless steel clad La Crosse 10x10 BWR fuel trith pellet diameter of 0.35 inches, a pitch of 0.565 and enriched to a "aximum of 3.93 percent U-235.
The Lacrosse BWR assemblies are 10x10 rod arrays with nominal dimen-sions of 5.61 inches on either side by 102.34 inches long and have a maximum enrichment of 3.93% U-235. Fuel rod lattice dimensional characteristics are as listed below:
rod pitch 0.565 inches rod outside diameter 0.396 inches pellet diameter 0.350 inches cladding 0.20 inches Type 348SS g
General Electric provided calculations, using a validated calculational b method, for the k infinity for the Lacrosse fuel of 1.35, and a multi-plication factor for normal storage in the stainless steel baskets of 0.855, assuming no burnup and the wall thickness of the pipes of the basket at the minimum tolerance value. The validity of the GE safety conclusion for the " normal" storage condition is conservatively confirmed by reference to Lantz' correlation for fuel storage ("A Graphic Method for Comparing K. in Fuel Storage Pools," in Transaction of American Nuclear Society, Vol. 27, 1977, p. 409).
For the unlikely accident in which a loaded fuel basket is dropped (or tipped) diagonally across the cask unloading pit to permit nine assemblies to extend about 42 inches out of the basket, GE reported a j k-effective of 0.923 0.007, under conservatively assumed conditions of assembly spacing. The GE calculations were independently confirmed by C. R. Marotta of the Transportation Branch using our (NRC) calcula-tional method with the 123-group cross sections which indicated the k-effective for the accident case to be 0.935 0.005. ,
m .,
d Files !!OV 17 IBM The GE lattice k-infinity value was confirmed by reference to the values in WCAP-2999 and to the values developed during the independent NRC accident case calculations reported above. It is agreed that the 1.38 k-infinity proposed by GE, which is above the 1.352 GE calculated for the most reactive Lacrosse fuel bundle, would not cause the storage array multiplication factor to exceed 0.90. Also, the arrangement of fuel in basket drop accident would be predicted to remain suberitical.
Therefore, the calculations reported by GE and independently confirmed by NRC establish that the Lacrosse fuel bundles should be well sub-critical under normal and accident conditions. Therefore, it is reccmmended by the amendment authorizing storage of Lacrosse fuel be approved.
Ii c L<^{ -
cL 4k F. M. Eni son Fuel Reprocessing and Recycle Branch Division of Fuel Cycle and Material Safety l
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