Abstract:
In a pressurized water reactor (PWR), the Li/K element in the primary loop coolant will be concentrated in the deposits (CRUD) on the surface of the fuel cladding, which will exacerbate the corrosion of zirconium alloy in cladding materials and have impact on the fuel life and safety performance. Therefore, it is necessary and urgent to carry out related research on the phenomenon. Finite volume method, coupled with the relationship between temperature field, pressure field and concentration field, is applied to establish the numerical calculation model of Li/K element in CRUD structure during concentration (CRUD model), which can simulate the concentration of Li/K element under different working conditions according to the design parameters of thermal and hydrochemical conditions of the reactor core. First of all, the accuracy of the CRUD model was verified by comparing with previous calculation results. Then, based on CRUD model, the influence law of core thermal design parameters (coolant temperature, pressure, heat flux, etc.), primary loop coolant water chemical conditions (Li/K concentration), and CRUD morphological parameters (thickness, porosity, etc.) on the distribution of Li/K ion concentration was analyzed, and a regular relationship which can be used to guide the design of reactor core parameter criteria and the design of fuel cladding material selection criteria was obtained.
