Design considerations, operating and maintenance experience with wet storage of Ontario Hydro's used fuel

The characteristics of Ontario Hydro's fuel and at-reactor used fuel storage water pools (or used fuel bays) are described. There are two types of bay, known respectively as primary bays and auxiliary bays, used for at- reactor used fuel storage. Used fuel is discharged remotely from Ontario Hydro's reactors to the primary bays for initial storage and cooling. The auxiliary bays are used to receive and store fuel after its initial cooling in the primary bay, and provide additional storage capacity as needed. With on- power fueling of reactors, each reactor of greater than 500 MW(e) net discharges an average of 10 or more used fuel bundles to bay storage every full power day. The logistics of handling such large quantities of used fuel bundles (corresponding to about 300 te/year of uranium for a 4 unit station) present a challenge to designers and operators. The major considerations in used fuel bay design, including site- specific requirements, reliability and quality assurance, are discussed