Present status of HTTR research and development, 1987

In the long term plan of atomic energy development and utilization, which was revised in June, 1987, the improvement of the thermal efficiency of nuclear reactors by extracting heat at higher temperature, the diversification of energy supply by utilizing nuclear heat, and the construction of a high temperature technology test and research reactor were decided as the policy of advancing high temperature technology. According to this policy, the Japan Atomic Energy Research Institute has exerted effort to establish and upgrade the basis of high temperature gas-cooled reactor technology, and carries out the detailed reactor design toward its construction. In particular, the optimization of the nuclear-thermal design of the reactor core, the realization of the design of a large irradiation test facility for fuel and material, and the analysis and evaluation of the plant safety are in progress. The reactor uses the pin-in-block type fuel made in Japan, the thermal output is 30 MW, the coolant temperature at the reactor exit is 950 deg C, and various irradiation test can be carried out with it. The researches on fuel assemblies, graphite, thorium fuel, Hastelloy XR, low alloy steel for pressure vessels, the reactor physics, the measurement and control of the reactor and so on are reported. (Kako, I)