Development of visualization technique for penetration behavior of simulant melt in sodium

Emura, Yuki; Kamiyama, Kenji  ; Matsuba, Kenichi  ; Isozaki, Mikio

In case of core disruptive accident in sodium-cooled fast reactors, it is thought that molten-core material will be discharged into the lower plenum and fragmented there due to fuel-coolant interactions. To understand this fragmentation behavior, we performed the simulation test in which molten stainless steel discharged into sodium pool and fragmentation behavior was observed using a visualization system combined X-ray and high-speed camera. Both successful visualization of fragmentation behavior by above visualization system and rapid cooling of molten stainless steel due to fragmentation are presented in this study.