Primary studies on factors for hydrogen concentration distribution in containment under severe accidents

Three factors that may affect the hydrogen concentration distribution in the containment were investigated. Calculation results by FLUENT and GASFLOW were compared. The results indicate that RNG κ-ε model can obtain better results in parameter fluctuation caused by turbulence, velocity field and hydrogen concentration field than the other models. The results calculated by algebraic model in GASFLOW are different from the other results in the simulation of mass diffusion, momentum diffusion, and parameters fluctuation. The effects of steam concentration and mass flow rate at the leakage on hydrogen concentration distribution have been also investigated. The results indicate that they are two important factors having effects on hydrogen concentration distribution. Turbulence modeling and simulation of turbulent buoyant jets and plumes, which need further study, are of importance in hydrogen concentration distribution in the containment under severe accidents. (authors)