Study on cooling process of decay heat removal systems in a reactor vessel of sodium-cooled fast reactor by scaled water experiments, 4; Effect of heat generation condition on natural convection flow field in reactor vessel

Tsuji, Mitsuyo ; Aizawa, Kosuke ; Kobayashi, Jun ; Kurihara, Akikazu ; Nakane, Shigeru*; Ishida, Katsuji*

Thermal-hydraulic phenomena caused by the natural circulation in a reactor vessel were investigated using scaled model water experiments simulating the reactor vessel in order to enhance safety and optimize the design and operation of decay heat removal systems under normal operation and severe accident conditions. This report shows the measurement results of temperature and PIV of natural convection flow field in the reactor vessel simulating an operation of dipped type direct heat exchanger. In addition, it is shown that the effect of dispersal condition of molten fuel on natural convection flow field in the reactor vessel.