Current Status of R&D and PIE Program for ADS Material Development in JAEA

Japan Atomic Energy Agency (JAEA) proposes transmutation of minor actinides (MA) by accelerator-driven systems (ADS). The ADS designed by JAEA is a system composed of a high intensity proton accelerator, a lead-bismuth eutectic (LBE) spallation target and a subcritical core. Since a beam window (BW) of ADS is exposed in a complex field of heavy irradiation by proton/neutron and corrosion by flowing LBE, JAEA plans to construct a materials irradiation facility at J-PARC. In the facility, a proton-beam extracted from J-PARC LINAC is injected to a LBE spallation target with 250 kW beam power, and post irradiation examination (PIE) is done for the samples such as BW of the target. Irradiation conditions in terms of temperature range, LBE flow rate, irradiation dose are from 400°C to 500°C, 1 m/s and 10 dpa/year, respectively. Along with conceptual design study of the facility, various R&Ds are being carried out by a LBE target mock-up loop “IMMORTAL” and a high temperature (550°C) material corrosion test loop “OLLOCHI”. Oxygen potential control systems for LBE flow have been also developed. As for PIE, specimen preparing procedure from the irradiated samples and BW including notching method and LBE cleaning technology have been investigated. Testing techniques for small specimens under LBE have been also developed. In this paper, we described the current status of facility development with major focus on the PIE program.