Atomic-Scale Simulation of Soluble Fission Products in UO2

The continuously increasing amount of energy produced within the nuclear fuel in the reactor is accompanied by an incessant increase of the number of fission products (FPs), which affects the thermo-mechanical behaviour of the fuel rods and eventually limits its lifetime. More precisely the FPs can contribute to an increase of the fuel volume, commonly referred to as fission product swelling, and lead to a chemical as well as a mechanical interaction between the ceramic fuel pellets and the metallic cladding material constituting the first barrier against the release of radioactive FP in the environment. A precise prediction of the moment at which such an interaction is established during the lifetime of a fuel rod in the reactor, or the moment at which the cladding material may fail as a result of such an interaction is strongly affected by the capability to predict the fuel swelling.