The HTGR is a helium gas-cooled and graphite-moderated thermal-neutron reactor with excellent inherent safety features. The HTGR meets various heat application requirements such as hydrogen production and power generation. The HTGR also meets the 3E+S policy targets in Japan’s Strategic Energy Plan. Our final target is demonstration of coupling of a nuclear reactor and heat application systems by connecting gas turbine and hydrogen production facilities to the Japan’s first HTGR, HTTR.