Design considerations for water pool storage of irradiated fuel by Ontario Hydro

The characteristics of fuel discharged from Ontario Hydro's reactors and of at-reactor irradiated fuel storage in water pools (or irradiated fuel bays) are described. With on-power fuelling of reactors, each reactor of >500 MW(e) net capacity discharges an average of 10 or more irradiated fuel bundles to bay storage every full power day. The design of facilities to enable operating staff to handle such large quantities of irradiated fuel bundles presents a formidable challenge. The major considerations in irradiated fuel bay design, including site-specific requirements, reliability and quality assurance are discussed, together with the salient design features of the irradiated fuel bay and support systems, i.e. fuel and transportation cask handling, cooling, purification and waste management. For safety considerations, the irradiated fuel in storage must retain its integrity. Also as fuel storage is an interim process, likely for up to 50 years, the irradiated fuel should be retrievable for downstream fuel management phases such as reprocessing or disposal. Evidence from a long-term experimental program indicates that there will be significant change in irradiated fuel integrity (and retrievability) over a 50 year wet storage period