Cask Design for Permanent Storage

In addition to the unavoidable material aging because of exposure to radiation from the radioactive material and hence corrosion is expected to be a concern in the long-term storage of nuclear waste. It has been further suggested that heat generation from radiation can drive the corrosion rate higher. Many cask designs have been proposed, and each with different materials of construction. The most common proposed materials are carbon steel, stainless steel, and concrete construction. 

In a September 2000 meeting on key technical issues regarding container life, the US Nuclear Regulatory Commission (NRC) and representative of the DOE discussed the ongoing research into the effects of corrosion processes on the lifetime of the containers (57). 

3 Effect of Location on Corrosion of Nuclear Storage Containers 

The current plans for a permanent nuclear storage repository are to build it at a relatively dry site at a depth of several hundred meters below earth s surface. It is thought that the presence of water will eventually corrode the storage containers. 

In the United States, the Yucca Mountain site (Fig. 3.30) is reported to be a good location because of the low water content in the site. The proposed design for nuclear waste disposal is for steel canisters containing the spent fuel to be stored within other steel canisters and buried horizontally in chambers 300 m below the earth s surface. The canisters were designed to last at least 1000 years, which will depend on the mountain itself to provide a natural barrier to survive the minimum 10,000 years required by the government however, there is no guarantee that the canisters at Yucca Mountain will be free from water flow for 10,000 years. 

---