OVERVIEW OF CRITERIA FOR INTERIM WET & DRY STORAGE OF RESEARCH REACTOR SPENT NUCLEAR FUEL

Abstract

Following discharge from research reactors, spent nuclear fuel may be stored "wet" in water pools or basins, or it may be stored "dry" in various configurations including non-sealed or sealed containers until retrieved for ultimate disposition. Interim safe storage practices are based on avoiding degradation to the fuel that would impact functions related to safety. Recommended practices including environmental controls with technical bases, are outlined for wet storage and dry storage of aluminum-clad, aluminum-based research reactor fuel.For wet storage, water quality must be maintained to minimize corrosion degradation of aluminum fuel. For dry storage, vented canister storage of aluminum fuel readily provides a safe storage configuration. For sealed dry storage, drying must be performed so as to minimize water that would cause additional corrosion and hydrogen generation. Consideration must also be given to the potential for radiolytically-generated hydrogen from the bound water in the attendant oxyhydroxides on aluminum fuel from reactor operation for dry storage systems.

Vacuum drying of advanced gas reactor fuel

“…When spent fuel is placed into storage, either wet or dry, the conditions must be controlled to prevent negative impacts on criticality, general containment of radionuclides, the ability to retrieve the fuel at the end of the storage period and 140 final disposal options [13]. The geometry of fuel is such that without a moderator, criticality is not possible, however in extreme cases when temperatures escalate there is a minor chance of criticality due to changes in fuel geometry due to creep.…”

“…Sindelar et al [13] have described dry storage existing as either unsealed or sealed systems. In 185 an unsealed system fuel is generally placed into a concrete vault or silo through which gas can flow to provide cooling and allows monitoring of the fuel condition, however the need to do this increases the costs and sealed systems are the pre-190 ferred option.…”