Sodium-cooled Fast Reactors (SFRs)

Started in the 1950s, Research and Development (R&D) for Sodium-cooled Fast Reactor (SFR) is now about to enter the demonstration phase for the design, construction, and operation of power plants. International collaborations such as the Generation IV International Forum (GIF) among involved countries are underway. Sodium has suitable properties as coolant material for the fast reactor. Design measures, however its chemical reactivity, should be taken into account. Oxide and metal are mainly used for fuel materials, and nitride is also available. Cooling system is in low pressure and high temperature, and includes primary and secondary sodium cooling system and thirdly water-steam system. There are loop and pool types: The former has components of the primary system connected with piping, and the latter has ones contained in the reactor vessel. GIF has been developing safety design criteria for the global standardization taking into account the lessons learnt from the Fukushima Daiichi nuclear power station accident. Worldwide R&D is underway to realize a closed fuel cycle as a sustainable energy supply system.