With the objectives of the effective use of resources, the reduction of the volume and harmfulness of high-level radioactive waste, etc., the basic policy of Japan is to promote a nuclear fuel cycle in which spent fuel is reprocessed and recovered plutonium, etc., are effectively used. As such, Japan has been developing fast reactors that utilize the fission reaction of plutonium using fast neutrons. After the Great East Japan Earthquake, the development environment for fast reactors changed drastically and in December 2016, it was decided to decommission the "Monju" prototype fast-breeder reactor. Although the situation has changed recently, the significance of developing fast reactors that enable the effective use of uranium resources and the reduction of the volume and harmfulness of radioactive waste remains unchanged. In December 2018, the Japanese government expressed in the "strategic roadmap" its expectations for the start of operations of a fast reactor around the middle of the 21st century. We are continuing to work on fast reactor development as a core company that is responsible for the development of fast reactors in Japan in order to achieve the "strategic roadmap" and realize the reduction of environmental load for a future that does not rely on fossil fuels.