Three-dimensional model of neutronic-thermo-hydrodynamic interaction in the core of light water reactors (stationary state)

We present a three-dimensional model of the neutronic-thermo-hydrodynamic interaction of static calculations in the core of light water reactors, constructed in the following way. The thermo-hydrodynamic model is the FLICA II C code type. It allows the treatment of a closed grid (core of boiling water) and an open grid (core of pressurised water). The exchanges of enthalpy and momentum of flow between canals are described by means of the concept of turbulent enthalpy conductivity and viscosity. The neutronic model is that of the TRIDENT code. The solution in three dimensions of multigroup diffusion equations is made by the finite element method. We apply this model to the calculation of the distribution of power through the core assembly of B.W.R.-6, at the beginning of life and 135Xe at equilibrium, of nominal power equal to -980 MWe. The results arrived at cross-check those published in the GESSAR safety report. (orig.)