A plutonium burner HTGR that can safely and efficiently reduce the amount of plutonium recovered from LWR's spent fuel has been proposed, and the basic technologies necessary for its realization have been established in cooperation with universities and Japanese manufacturers. In addition, R&D on the volume reduction of nuclear waste utilizing the features of HTGRs, such as high-efficiency power generation and high burnup, as well as on the reduction of potential toxicity through nuclear transmutation utilizing HTGRs are conducted.