Transformation temperatures and structures in uranium-fissium alloys

Abstract Solid state transformation temperatures and resulting structures are detailed for alloys of uranium with certain fission-product elements that might remain in a spent fuel from a fast reactor following pyrometallurgical refining. These elements, the aggregate of which is called “fissium” (Fs), are Zr, Nb, Mo, Tc, Ru, Rh and Pd. The phase relations can be related to those in the dominant U-Mo-Ru ternary system. The uranium gamma phase is stabilized down to 562° C, while the beta phase is entirely suppressed at high fissium contents. Certain crystallographic data are given and the minor phases that occur in the alloys are identified.