Low-Temperature, Vacuum-Assisted Drying of Degraded Spent Nuclear Fuel

Abstract

A variety of legacy, spent nuclear fuel, wastes are stored in below-grade, vertical, cylindrical, steel and concrete structures called 'tile holes' in Waste Management Areas (WMAs) at the Chalk River Laboratories (CRL) site. Inspections have revealed the presence of moisture in some of the tile holes, contributing to corrosion of the fuel-storage containers and fuel itself. A major fuel remediation initiative, the Fuel Packaging & Storage (FPS) Project, has been initiated to remediate the legacy fuels at CRL. The objective of the FPS Project is to stabilize the fuels by removing moisture and storing the fuel in a controlled atmosphere to reduce fuel corrosion and deterioration, such that future hazards and costs of handling the fuel are minimized.


A low-temperature (<100°C), vacuum-assisted-drying process, commonly known as Cold Vacuum Drying (CVD), has been evaluated for drying CRL legacy fuel. A test program has been conducted to assess the drying characteristics of CRL legacy fuels under CVD conditions using samples obtained from a legacy-fuel storage container retrieved from the WMAs at CRL. This paper describes the proposed CVD process, the drying tests and discusses the implication of the observed drying characteristics of corroded fuel samples on full-scale drying of CRL legacy fuel.