During the operation of a light water reactor, a fraction of the hydrogen produced by waterside corrosion is absorbed into the nuclear fuel cladding. When the hydrogen concentration reaches the solubility limit, a brittle zirconium hydride phase precipitates in the cladding, leading to a loss of ductility. To assess cladding integrity, an accurate simulation tool is needed to predict hydrogen distribution within the cladding and hydride precipitation. Such a model has been introduced into the fuel performance code BISON, developed at Idaho National Laboratory. However, recent studies have developed a more accurate understanding of the physical processes involved in hydride precipitation and dissolution. In this work the Hydride Nucleation-Growth-Dissolution (HNGD) model was implemented into BISON. Each step of the development was carefully verified. Validation simulations show that the HNGD model captures some experimentally observed physical phenomena that the previous model did not, especially during fast thermal transients.
