Summary of Methods for Studying the Chemical States of Nuclides In Nuclear Energy Systems

The chemical states of nuclides affect their physical and chemical properties including thermal conductivity, melting point, adsorption and desorption behavior, diffusion process, and chemical reactivity. It is an important issue in nuclear energy systems and spent fuel reprocessing. In this review, we summarize the theoretical calculations and experimental measurements to determine the chemical states of nuclides in nuclear energy systems. Software such as FactSage, HSC Chemistry and The Geochemist’s Workbench are generally used to determine the macroscopic-scale thermodynamic parameters such as thermodynamically stable phases. Quantum chemistry calculation software such as Gaussian 03 is employed for microscopic first-principles calculations to elucidate chemical reaction channels, microstructures, bonding characteristics, and rate constants. The experimental methods to determine chemical states of nuclides include X-ray, spectroscopy and chemical extraction.