The Corrosion and Compatibility of Vanadium Alloys for Fuel-Element Cladding

Vandium alloys have been identified as one of the leading alternate cladding materials for liquid-metal-cooled fast breeder reactors for circumventing the possible limitations of austenitic stainless steels. Two of the more important aspects of this usage on which little information is available are sodium corrosion and compatibility with ceramic fuels. In this study, a series of experimental vanadium alloy compositions were found to increase in weight and in hardness after 500-h exposure to flowing sodium containing <10 ppm oxygen at ∼790°C; these changes are due to the absorption of oxygen, carbon, and nitrogen. In 1000-h tests at 800°C, some incompatibility was observed only between vanadium alloys containing iron and uranium-carbide fuel. However, these screening tests have identified three vanadium alloy compositions as worthy of further study.