Major outcomes from OECD/NEA ROSA and ROSA-2 projects

Nakamura, Hideo  ; Takeda, Takeshi ; Satou, Akira ; Ishigaki, Masahiro ; Abe, Satoshi  ; Irwanto, D.

The OECD ROSA and ROSA-2 joint research projects have performed 19 LSTF experiments to simulate 9 subjects on reactor accidents and abnormal transients. Detailed data were obtained to well understand the accident phenomena, which is suitable for V and V of both 1-D best estimate (BE) safety analysis codes and 3-D CFD codes. The research subjects and test conditions were defined with participants from 15 NEA member and non-member countries to well represent such accident phenomena as multi-dimensional, multi-phase, parallel channel flows under influences of non-condensable gas within world largest LSTF under full-pressure conditions. New activity was done in the ROSA-2 Project such as blind analysis and counterpart testing with the OECD PKL-2 Project to clarify and solve issues in the utilization of the BE and CFD codes. Major outcomes from such ROSA and ROSA-2 Projects are discussed through selected three types of subjects. Remaining issues are pointed-out as well.