Mitsubishi FBR Systems, Inc. (MFBR) is a company formed on July 1, 2007, by Mitsubishi Heavy Industries to develop Fast breeder reactor technology.
[2] However, in 2014 Japan agreed to cooperate in developing the emergency reactor cooling system, and in a few other areas, with the French ASTRID demonstration sodium-cooled fast breeder reactor, which was subsequently cancelled in August 2019.
[3][4][5] In 2016, the development of Japanese fast reactors halted as a result of the government decision to decommission the Monju Nuclear Power Plant following problems with the plant including sodium leakage.
[6] In January 2022, Mitsubishi Heavy Industries and Mitsubishi FBR Systems signed a Memorandum of Understanding with TerraPower to cooperate on the development of sodium-cooled fast reactors.
Under the agreement TerraPower would acquire Japanese know-how and test facilities related to fast reactors.