Fast Breeder Reactor

A Fast Breeder Reactor is a reactor that uses fast neutron, and generates more nuclear fuels(plutonium 239) than that consumed when generating power to enhance dramatically the efficiency of the use of resources. Nuclear fission by fast neutron causes the increase in neutrons generated. Furthermore, because the sodium coolant absorbs fewer neutrons as compared to light water reactor, more neutrons remain within the reactor. Increased number of neutrons causes higher proportion of plutonium 239 converted from uranium 238 and yields more plutonium than original nuclear fuel.
In Japan, an experimental fast-breeder reactor "Joyo" was first developed by the Japan Atomic Energy Agency(JAEA)(former Power Reactor & Nuclear Fuel Development Corporation). This is a reactor without electric generating facilities, and started operation in 1977 with the aim of accumulating technical experience on the fast-breeder reactor.
MHI was in charge of the design of the core and the manufacture of the rotary plugs, intermediate heat exchangers and secondary coolant system. Furthermore, MHI actively participated in the Mk-III(3) modification works that increased the output of 50 MW to 100 MW then to 140 MW.