Thermodynamics of the Zr-H binary system related to nuclear fuel sheathing and pressure tube hydriding

The thermodynamic database of the Zr-H system was updated using Density Functional Theory (DFT). In the present work, the first-principles calculations were performed using VASP (Vienna ab initio Simulation Package), which is based on pseudo-potentials and a plane wave basis set. The enthalpies of formation of ɛ-ZrH2, δ-ZrH2−x, and γ-ZrH were calculated at 0 K and it is shown that the formation of all three hydrides is spontaneous, under predicted PWR and CANDU reactor core electrochemical conditions.