Irradiation techniques under high pressurized water using hybrid type saturated temperature capsule in the JMTR

The IASCC is one of the major concerns on the integrity of in-core materials not only for the LWRs but also for the materials to be cooled by water in fusion reactor. It is desired to irradiate test materials in a high temperature water environment in order to investigate simultaneous effects of irradiation and corrosive environments, which are essential for the study of IASCC. In the JMTR, an irradiation rig named the SATCAP was developed and applied for the IASCC study. Inside of this capsule, cooling water is boiling during irradiation due to heat generated by gamma heating, thus the temperature of the specimens is kept nearly at saturation temperature of water. Recently a new hybrid type SATCAP with electric heaters and vacuum control systems was developed to improve temperature control capability of the original SATCAP. A design and results of performance test of the new hybrid type SATCAP are reported. (orig.)