Intense neutron source for material research in fusion reactor R and D program

The present status of research and development is described on the intense neutron sources for material research for fusion reactors. Since the material of the first walls of fusion reactors is irradiated heavily by 14.2 MeV neutrons, the damage of the material due to the neutron-induced reaction is serious. For the simulation test of the damage, intense neutron sources are required. The construction of intense source is now in progress. The planned neutron sources are RTNS-2, FMIT, FNS (JAERI), and OKTAVIAN (Osaka University). The irradiation tests with these machines are made for small size test pieces. Therefore, the irradiation of large samples with fast breeder reactors is also important. The RTNS-2 is now in operation. The neutron yield is about 1 x 10¹³ n/s, and the obtained neutron fluence is 3 x 10¹⁸. The FNS (JAERI) and the OKTAVIAN (Osaka University) will be in operation in the spring of 1981, and the expected yield is 1 x 10¹² n/s. The FMIT will be constructed at HEDL, U.S.A., and this machine will produce fast neutrons by the Li(d,n) reaction. A 35 MeV linear accelerator will accelerate intense deuteron beam which hits a liquid lithium target. The neutron yield of 10¹⁴ n/cm².s is expected in a narrow conical space in front of the target. The tritium handling system for neutron sources by T(d,n) reaction is a problem to be studied. (Kato, T.)