Fuel storage and handling facilities of PWRs consist of fresh fuel storage facilities, spent fuel storage facilities, spent fuel pit water cleanup system, refueling crane, spent fuel pit crane, fuel handling crane, and fuel-carrying facilities [45]. Figure 3.70 illustrates a schematic view of fuel storage and handling facilities and Table 3.14 gives the main specifications of the fuel storage facilities.

Fuel storage and handling facilities are designed to prevent criticality in any cases to be expected by using a geometrically safe arrangement or other suitable means. Therefore, fuel storage facilities are designed to secure subcriticality even when fully loaded and flooded with full-density unborated water. Fuel handling facilities are designed to have a structure in which only one fuel assembly can be handled independently to prevent criticality.

(1) Fresh Fuel Storage Facilities

Fresh fuel storage is constructed of reinforced concrete, established in an independent area of the fuel handling building. Fresh fuel assemblies are stored one by one in stainless steel racks in a dry condition. The fresh fuel storage is constructed to prevent water flooding and to be able to drain water when it enters the storage.

The storage capacity of the fresh fuel storage is usually set considering the number of fresh fuel assemblies to be loaded and alternative storage of fresh fuel in the spent fuel pit. In Table 3.14, the storage capacity corresponds to about 23 % of the whole core fuel. Fresh fuel storage racks are designed to assure that the effective multiplication factor of less than 0.95 must be maintained even in a severe condition such as unborated water flooding for the maximum storage amount of fresh fuel, by holding a proper fuel assembly spacing to prevent criticality of storage fuel. Moreover, the fresh fuel storage racks are designed to prevent criticality even filled with unborated water of the optimum moderating density.