The inherently-safe fluidized-bed boiling water reactor concept

A new inherently-safe Boiling Water Reactor (BWR) design has been conceived. A feature of this design is the combination of the fluidized-bed concept and the density-lock mechanism of PIUS (a design proposed by a previous author). In this design, channels in which spherical fuel elements fluidize hydraulically connect with a cooling water tank through the density-lock mechanism. Hence the fuel elements naturally fall to the bottom of the tank in any accidents including LOCA and ATWS, and are kept under subcritical conditions and cooled to remove their decay heat. A preliminary fluidized experiment suggested that the fuel elements fluidized excellently at a coolant flow velocity of half of that in a BWR and their deformation due to collisions with each other and with the channel wall did not affect their integrity. (author)