Compatibility of U – Mo and V – Ti – Cr аlloys at 900 oC

Abstract

Metallic fuel has long served as a common nuclear fuel. The Generation IV Reactors programme considers metallic fuel feasible for Generation IV reactors due to its unique physico-chemical characteristics. In spite of all the advantages offered by metallic nuclear fuel (such as density and heat conductivity), there are certain factors limiting its use. The main factors include fuel swelling and interaction with steel cladding. The problem of swelling can be resolved by lowering the smeared density of nuclear fuel to 75% of theoretical values, which can be achieved by reducing the section of the fuel column and opening the fuel-cladding gap. An optimal solution would be to use porous fuel, the theoretical density of which is 75%. The problem of metallic fuel-steel cladding interaction is caused by a uranium-iron eutectic. One of the alternatives could be to start using vanadium alloys (V – Ti – Cr) for claddings as their eutectic interaction with uranium starts at higher temperatures. The authors carried out an experiment to understand how V – 4Ti – 4Cr alloys would interact with U10Mo alloys. The experiment was conducted at the temperature of 900 oC for 11 hours. A slight interdiffusion of the components was observed, and a high degree of similarity between vanadium alloys and oxygen and nitrogen was noted.