An Alternative Strategy for Thermodynamic Evaluations of Experimental U-Me Phase Diagrams to Resolve Considerable Experimental Discrepancies

Abstract

Post irradiation examinations of burned-up nuclear fuels reveal a host of fission products. The changing chemistry of the fuel has effects on the deformation of fuel pellets and interactions with the cladding. Thus, mechanisms of various types of corrosions have been the focus of both experimental and thermodynamic investigations during the past decades. The construction of uranium related experimental phase diagrams are time consuming, costly, and fraught with many technical difficulties (e.g., accuracy in high temperature measurements and contamination of samples by crucible materials). Both effects have been found in the experimentally constructed phase diagrams for U-Me systems (where Me = Ru, Rh, and Pd). The experimental discrepancies become apparent as the Me component changes from Ru to Pd. Resolving the discrepancies in these three systems has led to an alternative strategy being developed for the optimization of phase boundaries and identification of experimental fallacies.