PRECIP-2, Zircaloy Cladding Oxidation Simulation for LWR under LOCA Conditions

1 - Description of problem or function: PRECIP-2 simulates zircaloy cladding oxidation under LOCA conditions of LWRs. The code calculates oxygen concentration distribution across the cladding wall by solving the diffusion equation with moving boundary conditions, taking into account the structure change of the beta- phase, i.e. alpha precipitation during the cooling period. The code also predicts total oxygen uptake, thicknesses of alpha, beta and oxide layers. 2 - Method of solution: The finite difference method is used to solve both diffusion equations and the heat transfer equation with moving boundary conditions. 3 - Restrictions on the complexity of the problem: The maximum number of radial nodes in the cladding is 1000. The calculation is done in cylindrical coordinates