Metal Container Materials for Nuclear Waste

Abstract

Selecting materials to contain high-level nuclear waste presents an unparalleled challenge to materials scientists and engineers because of the very long times required for containing the waste and the high degree of certainty required when predicting a container's long-term performance. Material endurance without severe degradation is the primary property sought in container materials. There are, of course, additional factors related to mechanical properties, fabricability and weldability, and economics, but these factors are usually secondary to the chemical properties of the material. Metals and alloys have been given prime consideration as container materials because metal materials are ductile and tough, they can be easily fabricated in mass quantities and large container sizes, and they can be readily joined to create intact gas-tight seals between parts.In selecting a suitable container material, the container's environment is the most important consideration. Several geological formations and resulting geochemical environments are under consideration as disposal sites in different countries. This short review will discuss the principles governing corrosion of the primary container materials being considered in various national nuclear waste disposal programs and will show how this background can guide materials selection. Important candidate materials are then considered along with examples of how these materials will be expected to perform under repository conditions existing in a range of national programs.