[1C13-17] Next Generation Reactor Safety

[1C15] Development of failure mitigation technologies for improving resilience of nuclear structures

(12)Study of buckling and post-buckling of vessels for failure mitigation at extremely high temperature

*Naoto Kasahara¹, Masato Murohara¹, Takuya Sato¹ (1. UTokyo)

Keywords:Next generation reactors, Reactor vessel, Beyond design basis events, Fracture control, Buckling

This study proposes mitigation methods of failure consequence against beyond design basis events by fracture control concept. Fracture control mitigates high impact failure modes on safety by prior failure low impact failure modes. As a specific example, the creep rupture of the reactor vessel wall due to self and internals-weight at extremely-high temperature due to the loss of cooling function of the next-generation fast reactor is mitigated by redistributing the load to the lower head, and the liquid level is maintained for a long time. The lower head buckles due to contact with the floor, however the post buckling behavior is stable and the boundary is not damaged, so that the liquid level of the reactor vessel can be maintained.