Development of fluid-rigid strongly coupled particle method for the estimation of the relocation behavior of damaged in-core structures

Fukuda, Takanari ; Yoshida, Hiroyuki  

The presenters have developed a new fluid-rigid coupled particle method for the estimation of the relocation of in-core structures mechanically interacting with fluid phases existing in a reactor. Amid a severe accident, there might exist relatively large in-core structure, the scale of which is comparable to that of the maximum spatial scale of the fluid (e.g. scale of containment vessel). Such a calculation configuration can result in numerical instability with the conventional fluid-rigid weakly coupled methods. Hence, we have derived fluid-rigid strongly coupled time-development equations on the basis of Hamilton's least action principle and developed a new particle method for solving those equations numerically.