Spent fuel behavior in dry storage

Dry storage is emerging as and attractive and timely alternative to complement wet storage and assist utilities to meet interim storage needs. Spent fuel has been handled and stored under dry conditions, at least for brief periods, almost from the beginning of nuclear reactor operation. Drywell and vault facilities have been used to store certain types of fuel, beginning in 1964. More recently, programs have developed to demonstrate dry storage of irradiated Zircaloy-clad fuel in metal casks, drywells, silos and vaults. Hot cell and laboratory studies also are underway to investigate specific phenomena related to cladding behavior in dry storage. A substantial fraction of the US LWR spent fuel inventory has aged for relatively long times and has relatively low decay heats. This suggests that much of the US fuel inventory can be stored at relatively low temperatures. Alternatively, rod consolidation of the older can be considered without exceeding maximum cladding temperatures.