Anisotropic azimuthal power and temperature distribution as a driving force for hydrogen redistribution

The reactor environment, in which nuclear fuel operates, requires improved multi-dimensional fuel and cladding simulation and analysis to accurately describe fuel behavior. The high-fidelity fuel performance code BISON was developed at Idaho National Laboratory (INL) to address this need. BISON is a three-dimensional finite-element based fuel performance code. In the high temperature environment of a reactor, the zirconium in the cladding undergoes waterside corrosion in primary water, releasing hydrogen in the process. Some of this hydrogen is absorbed by the cladding. Once hydrogen is absorbed in the cladding, its distribution is extremely sensitive to temperature, stress and concentration gradients. Hydrogen migrates down temperature and concentration gradients and at a high enough concentration, precipitates as hydrides which can embrittle the cladding. This paper describes a development effort to validate the hydrogen distribution prediction capabilities of the BISON code. The project is divided into two primary sections: first, using a high fidelity multiphysics coupling to accurately predict temperature gradients as a function of radial, azimuthal, and axial directions (r, θ, and z), and using experimental data to validate a previously developed analytical hydrogen transport and hydride precipitation model implemented in BISON.