Liquid lithium target under steady state ultra high heat load of 1 GW/m2 range for International Fusion Materials Irradiation Facility (IFMIF)

International Fusion Materials Irradiation Facility is an accelerator-based neutron source using the D–Li stripping reaction to provide high intensity neutron field with energy of 14 MeV and damage dose rate of around 20 dpa/year for fusion materials development. To handle the intense deuterium beam power up to 10 MW which corresponds to ultra high heat flux of 1 GW/m2, the liquid Li jet flow with a maximum velocity of 20 m/s and a concave flow configuration is necessary. According to thermal–hydraulic analysis, an induced centrifugal force with a radius of concave back wall (25 cm) realized that the Li temperature is lower than the Li boiling point. To confirm the hydraulic characteristics of Li flow, water jet simulation experiment has been done. Moreover, validation experiment in Li loop is under way in Osaka University. In addition, a permissible heat load of the Li flow under a surface heat deposition has been discussed.