Modelling the kinetics of microstructure evolution and irradiation damage within Zr cladding for nuclear fuel

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This research will investigate the kinetics of microstructure evolution and irradiation damage within Zr cladding of nuclear fuel rods. Understanding Zr behaviour is key for next generation of nuclear reactors, especially Small Modular Reactors (SMRs), where fuel design has yet to be decided. Statistical models of phase transformation will be coupled with continuum models of diffusion to assess kinetics across the cladding, utilising multi-component descriptions of diffusion. A thermodynamic database will be used to determine phase stability, equilibrium compositions, and ultimately the chemical driving forces for phase transformations. Development of a mobility database will be explored to complement the existing thermodynamic database. Through implementing a thermodynamic description of kinetics, it is possible to capture the evolution of multiple metastable and equilibrium phases. The modelling will explore different hypotheses regarding the kinetics of irradiation damage within the Zr cladding. The models will be developed and validated against experimental data generated by National Nuclear Laboratory (NNL) from inservice reactor cladding. Understanding the kinetics of irradiation damage is vital in enabling informed decisions regarding component lifespan, both in reactor and after removal during storage. This work will steer decisions for the type of fuel cladding used in SMRs, as well as the lifespan and subsequent storage considerations. Finally, this project also has the advantage of being modelling based, and hence achievable given the current COVID restrictions.