Development of evaluation model for wastage environment under tube failure accident in steam generator of sodium-cooled fast reactor

In order to establish a safety evaluation method of a steam generator in sodium-cooled fast reactors, a computer program called SERAPHIM to calculate compressible multicomponent multiphase flow with sodium-water chemical reaction under tube failure accident has been developed. In this study, a numerical model for liquid droplet entrainment from an interface of the gaseous jet and its transport was newly constructed to evaluate the environment of the liquid droplet impingement erosion. Applicability of the SERAPHIM program which incorporates the droplet entrainment/transport model was investigated through the analysis of vertical discharging of water vapor in the liquid sodium pool. The numerical analysis reproduced the under expansion of the vapor jet, which appears under the actual condition of the tube failure accident. The calculated peak temperature agreed with the experimental results well. Also, appearance of the dispersed phase of droplets in the reacting jet and movement with the supersonic gaseous flow were calculated successfully. (author)