FBR tank type reactor

A plurality of coolant (liquid sodium) circulation pumps or a plurality of heat exchanger are not arranged on an identical circumference of a circle are partially arranged being displaced along radial direction to the inner side and the outer side of the circumference of a circle, in a reactor container. Sodium near the liquid surface passes through gaps between recycling pumps and heat exchangers disposed in adjacent with each other. The streams directed to the upper mechanisms of the reactor core are curved to left or right to form stable swirling streams in one direction along the upper mechanisms of the reactor core. Accordingly, since counter flows and colliding flows streams are removed, occurrence of fluctuation on the liquid sodium surface and waving swirling streams can be suppressed. This can prevent involvement of cover gases, to previously prevent melt down accident of the reactor core. Further, since the liquid surface of sodium is made stable, repeating thermal stresses to structural components due to fluctuation of liquid surface or waving can be reduced, to ensure integrity of the reactor core and the structural materials. (I.N.)