Current Thermal Hydraulic Activities on Sodium-cooled Fast Reactors in Japan

Focusing on key issues on thermal hydraulics of sodium-cooled fast reactors (SFRs), namely, natural circulation decay heat removal, gas entrainment, sodium combustion, and sodium-water chemical reaction, this paper reviews the progress of evaluation methods on them. These issues are identified as safety concerns of SFRs in the safety design criteria (SDC) and safety design guidelines (SDG) for Generation-IV SFRs. To meet the SDC and SDG, design studies and related researches are being carried out in an SFR development project in Japan. The goal of the thermal hydraulic studies is to assure higher level of safety and reliability along with economic competitiveness with concurrent light water reactors. (author)