Melting Technology for Uniformity Control of U–10Zr Alloy

Abstract

U–Zr alloy has the advantages of high thermal conductivity and anti-radiation swelling performance, as a promising metallic nuclear fuel for its fast breeder reactor. In this paper, U–10Zr alloy was prepared by multi-induction melting method and chemical analysis, optical metallography, XRD and SEM were used to investigate the effects of melting technology on the distribution of Zr as well as the phase composition in U–10Zr alloy. The results show that the dissolution of Zr in U is more complete in the second smelting process. The chemical composition is homogeneous while distribution of U, Zr and C is different in different location. The first smelting by vacuum induction removes more impurity of the ingots. The distribution of zirconium and carbon in the transverse-direction of U–10Zr ingots is more uniform. U–10Zr alloy exists in an acicular martensite state along with small quantity of nonmartensitic α phase. The zirconium element is more easy to form carbide and nitride with the C and N elements than the uranium. The as-cast U–10Zr alloy is composed mainly of α phase and δ-UZr₂ phase.