View source for W3P86-1655, Forwards Addl Info to Assist NRC in Resolving Proposed Tech Spec Change NPF-38-18 Re Increase in Fuel Enrichment for Cycle 2

{{Adams
| number = ML20204H302
| issue date = 08/04/1986
| title = Forwards Addl Info to Assist NRC in Resolving Proposed Tech Spec Change NPF-38-18 Re Increase in Fuel Enrichment for Cycle 2
| author name = Cook K
| author affiliation = LOUISIANA POWER &amp; LIGHT CO.
| addressee name = Knighton G
| addressee affiliation = NRC OFFICE OF NUCLEAR REACTOR REGULATION (NRR)
| docket = 05000382
| license number = 
| contact person = 
| document report number = W3P86-1655, NUDOCS 8608080074
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE, UTILITY TO NRC
| page count = 3
}}

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P. O. BOX 60340 LO UISI POWER     AN A
                          & LIGHT   / 317 NEW BARONNE
                                                           +
ORLEANS, LOUISIANASTREET 70160   +
(504)595-3100 Uti0 $ N N U August 4, 1986 W3P86-1655 A4.05 QA Mr. George W. Knighton, Director PWR Project Directorate No. 7 Division of PWR Licensing-B Office of Nuclear Reactor Regulation Washington, D.C. 20555

==SUBJECT:==
Waterford SES Unit 3 Docket No. 50-382 Additional Information Concerning Increased Fuel Enrichment

==REFERENCE:==
W3P86-2163 dated June 24, 1980

==Dear Mr. Knighton:==

By the referenced letter LP&L submitted a proposed Technical Specification change (NPF-38-18) requesting an increase in fuel enrichment for Cycle 2.
Subsequently, we have had discussions with your staff concerning various technical questions associated with the change. Attached please find ad-ditional information to assist you in resolving NPF-38-18. Should you have further questions, please feel free to contact Mike Meisner at (504) 595-2832.
Yours very truly, K. W. Cook Nuclear Support 6 Licensing Manager KWC/MJM/ch Attachment cc:    B.W. Churchill, W.M. Stevenson, R.D. Martin, J. Wilson, D.B. Fieno, NRC Resident Inspector's Of fice Waterford 3 8608080074 860304 PDR    ADOCK 05000302 P                  PDR                                                                g O
                                                                                                 \'
                              "AN EQUAL OPPORTUNITY EMPLOYER"

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       <                               ATTACHMENT I W3P86-1655 Mr. G.W. Knighton Temperature Effects on Reactivity For the criticality analysis associated with the storage of 4.1 weight
          % U-235 fuel, the temperature of the rack, the concrete walls and all componente of the fuel assembly is assumed to be at 20 degrees Celsius.
The temperature value of 20 degrees Celsius was used in the analysis to determine the most conservative values for the neutron capture cross-section in the solid materials for the spent fuel storage rack, fresh fuel storage rack and containment temporary storage rack. As an additional conservatism, the fuel assemblics in the racks were assumed to be moderated by pure water at a temperature of 4 degrees Celsius which corresponds to the maximum density for water of 1 gm/cc.
Increasing moderator temperature from the nominal 4 degrees Celsius (water density of 1.000) results in a monotonically decreasing reactivity.
Fuel Assembly Handling Accident LP&L has determined that, in accordanc( with the Standard Review Plan, a fuel assembly drop to a horizontal position is the most limiting accident event. Other potential drops (e.g. directly onto a loaded cell or onto the rack but leaning on the edge of the pool) result in geometrical con-figurations significantly less reactive. For a fuel assembly drop accident (containing 4.1 weight % U-235) onto the top of fuel in the spent fuel or fresh fuel storage racks the fuel assembly is assumed to come to rest horizontally. In this configuration the dropped fuel assembly will be separated by at least 30 inches of water from the active length of fuel assemblies in the storage racks. Because the separation distance is so large, the contribution of the dropped fuel assembly to the reactivity of the stored fuel is negligible. The containment temporary storage rack allows for the storage of up to 5 fuel assemblies during refueling operation when the refueling canal is filled with borated water. While the critical geometry and other arguments presented for the spent fuel and f resh fuel storage racks are valid, the liklihood of a dropped fuel assembly coming to rest horizontally on the temporary storage rack is remote due to the small horizontal cross-section of the containment temporary storage rack. Consequently, fuel assembly drop accidents for all storage racks will not result in an increase in reactivity above that calculated for the nominal design storage rack.
For the nominal and accident conditions described above the criticality calculations were completed taking no credit for soluble boron. Soluble boron is normally present in the spent fuel storage pool (credit for whlch is permitted under accident conditions) and would further reduce the l         maximum keff for all credible accidents to substantially less than 0.95.
I i

W3P86-1655 Mr. G.W. Knighton Consequently it is concluded that fuel handling accident conditions will not adversely affect the criticality safety of the spent fuel pool, fresh fuel or containment temporary storage racks.
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