FBR type reactor

In a FBR type reactor, reflectors are disposed near the outer circumference of a reactor core to reflect neutrons efficiently and conduct combustion/breeding of nuclear fuels efficiently. The reflectors themselves are immersed in primary coolants, to utilize heat generated from the reflectors as an output of the FBR type reactor, thereby improving the efficiency of the reactor. Next, neutron shieldings are disposed at the inside of the reactor container and in a coolants flow channel to utilize heat generated from the neutron shielding material as the output of the reactor thereby reducing the amount of neutrons irradiated to the reactor container and the out side of the container. As a result, heat efficiency of the reactor can be increased to reduce irradiation amount of neutrons in the reactor container thereby enabling to use inexpensive stainless steel as a component material of the reactor container. Moreover, requirement for sealing property relative to heat of shielding components for containing the FBR type reactor and cooling facilities accompanying thereof and the air in activated shielding structures can be reduced, so that the shielding structures and cooling facility can be reduced in the size and simplified. (N.H.)