Theoretical study on the corrosion of thorium nuclear fuel by water: The effect of two-state reaction mechanism

Abstract The title reaction was investigated by DFT calculations. This process realizes in two steps. In the first step, singlet and triplet potential energy surfaces cross each other. We found that two-state reaction (TSR) mechanism is involved, enabling singlet product to be favored energetically. Then, ThO continues to react with H2O to form ThO2. Only the activation energy of singlet addition–elimination channel matches well with experimental reports. This work illustrates the occurrence of TSR mechanism in the corrosion of actinide nuclear fuel and further suggests a potential yet crucial impact on related fields. It deserves particular attention.