Spent Fuel Storage

This chapter addresses the storage of spent fuel in the spent fuel pool (SFP) and dry storage casks at commercial nuclear reactors. The discharged fuel is placed in spent fuel storage racks in the SFP until it is completely filled, and then the spent fuel assemblies are transferred to dry storage casks on the nuclear plant premises. The flux-trap racks are qualified for storage of fresh fuel and fuel which has been fully irradiated in the reactor, whereas the non-flux-trap racks are qualified for storage of fully-irradiated fuel and therefore are used to store the majority of the fuel in the SFP. In the geometric models used for the calculations, each fuel rod and its cladding are described explicitly, and reflecting or periodic boundary conditions are used in the radial direction which has the effect of creating an infinite radial array of storage cells.