Fast reactors. Preparations have begun in Russia to build Unit 5 of the Beloyarsk Nuclear Power Plant, featuring the BN-1200M sodium-cooled fast neutron reactor. This will be the first mass-built power unit equipped with a Generation IV reactor. For many years, the Beloyarsk NPP has successfully operated power units with sodium-cooled fast neutron reactors, BN-600 since 1980 and BN-800 since 2015. These are the largest units of their kind in the world and rank among the safest and most reliable nuclear reactors globally. The BN-1200M will be the world’s most powerful fast neutron reactor in operation. First concrete pouring for the facility is scheduled for 2027. “With the start of work on Unit 5, Beloyarsk reaffirms its status as a leader in the development of fast neutron reactors. This technology is an integral part of our advanced project to close the nuclear fuel cycle,” said Rosatom Director General Alexey Likhachev during a visit to the plant.