Development of an assessment methodology for the molten-fuel discharge behavior in the core disruptive accident of sodium-cooled fast reactors

Kamiyama, Kenji  ; Tobita, Yoshiharu; Suzuki, Toru; Matsuba, Kenichi  

A methodology for molten-fuel discharge behavior is required to realistically assess core-disruptive accidents (CDAs) of sodium-cooled fast reactors. In the present study, the SIMMER code was utilized as a technical basis since this code can simulate the multi-phase, multi-component fluid dynamics with phase changes which are supposed to take place around the CRGT during the discharge process. First, dominant phenomena affecting fuel discharge through the CRGT are identified based on parametric calculations by the SIMMER code. Next, validations on the code models closely relating to these phenomena were carried out based on experimental data. It was shown that the SIMMER code with some model modifications could reproduce the experimental results appropriately. Through the present study, the assessment methodology for the molten-fuel discharge through the CRGT was developed.