Dropped Shipping Cask

Toxic Gas Purificatien Events Fuel Corrosion in Disassembly Basin Dropped Shipping Cask... 

A structural fouh in a K-, L-, m P-Reactor Disassembty Basin wall may result from a dropped shipping cask impacting the floor or wails of the Disassenfoty Batin, or may be the result of a random fouh in a batin wall l er way,. an uncontrolled rdease of basin water results. The dropped shipping cask is anafyzed in Section 8.3.2.21. 

For the dropped shipping cask event, h is noted that many transfer operations have been conducted s ely and v out incident over the life of the reactors. Since no shipping cask drops have bem observed, rare event theory can be applied (Ref 8-30). The rare event theory was applied in the PHAs (Ref 8-17, 8-Sl) to determine the probability of a dropped shipping cask, / proximatdy 100 reactor-years have dapsed at SRS, thus the probat fy can be conservative... 

FORCES ASSOCIATED WITH A DROPPED SHIPPING CASK... 

Because the maximum leak rate fix>m a K-, L-, or P-Reactor IMsassembly Basin crack assodated with a dropped shipping cask is 105 gpm (Ref 8-17, 8-51), the consequences of a dropped shipping cask are bounded by several other Disassembly Badn draindown scenarios analyzed in Section 8.3.2.1, which have greater leak rates (for example filtration systm leak at 1000 gpm). 

The shipping cask is oredited in events involving the transportation aiKl loading of the shipping cask (dropped shipping cask inadvertent criticality within the shipping cask). If the cadmium plates or blanks are not used, the chances for inadvertent criticality increase. 

The Disassembly Basin walls and floors are credited to some degree in the analyses of all postulated acddents fl>r providing confinement of contaminated basin water in a manner which minimizes its rdease to the environment The floors and wall are designed to withstand all scenarios except DBE and the dropping of a shipping cask. 

The K-, L-, and P Reactor Disassembly Basin walls and floors are also passive components. As such, the walls and floors are always available. The walls and floors are designed to provide leak-free confinment of basin water unless foe walls and/or floms are damaged during a DBE or shipping cask drop evoit. 

The structures of Buildings 105-Is 105P are not susceptible to ilure during design basis earthquakes, tornadoes, and high winds, however, during seismic and shipping cask drop... 

Accidents with spent fuel outside the containment Shipping cask drop EVST (Ex-vessel storage tank) / FHC (Fuel handling cell) system leaks Loss of forced cooling to EVST... 

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