H. Kawamura

Development of advanced tritium breeders and neutron multipliers for DEMO solid breeder blankets

In efforts to develop advanced tritium breeders, the effects of additives to lithium titanate (Li2TiO3) have been investigated, and good prospects have been obtained by using oxide additives such as TiO2, CaO and Li2O. As for the neutron multiplier, the development of a real-size electrode fabrication technique and the characterization of beryllium-based intermetallic compounds such as Be?Ti and Be?V have been performed. Properties of Be?Ti alloys have been found to be better than those of beryllium metal. In particular, steam interaction of a Be?Ti alloy was about 1/1000 as small as that of beryllium metal. These activities have led to bright prospects for the realization of the water-cooled DEMO breeder blanket by application of these advanced materials.

In-pile test of Li2TiO3 pebble bed with neutron pulse operation

Abstract Lithium titanate (Li 2 TiO 3 ) is one of the candidate materials as tritium breeder in the breeding blanket of fusion reactors, and it is necessary to show the tritium release behavior of Li 2 TiO 3 pebble beds. Therefore, a blanket in-pile mockup was developed and in situ tritium release experiments with the Li 2 TiO 3 pebble bed were carried out in the Japan Materials Testing Reactor. In this study, the relationship between tritium release behavior from Li 2 TiO 3 pebble beds and effects of various parameters were evaluated. The ( R / G ) ratio of tritium release ( R ) and tritium generation ( G ) was saturated when the temperature at the outside edge of the Li 2 TiO 3 pebble bed became 300 °C. The tritium release amount increased cycle by cycle and saturated after about 20 pulse operations.

In-situ tritium release behavior from Li2TiO3 pebble-bed

Abstract The engineering data on neutron irradiation performance of fusion blanket are indispensable to design the fusion blanket. In this study, an in-situ irradiation test of the Li 2 TiO 3 pebble bed was carried out at the J apan M aterials T esting R eactor (JMTR), and the effects of various parameters, i.e. sweep gas flow rate, irradiation temperature and hydrogen content in sweep gas on tritium release were evaluated.

The Effect of Joint Condition on Mechanical Properties of Irradiated Hot Isostatic Pressed Joints

For fabrication of the International Thermonuclear Experimental Reactor blanket, a study was made on the effect of surface roughness (Ry) at the joint boundary on tensite properties of copper alloy/stainless steel hot isostatic pressed (HIP) joints after neutron irradiation. Three different types of joints (type-A: Ry = 1 µm, type-B; Ry = 10 µm, and type-C: Ry = 30 µm) were prepared and irradiated up to 1.5 displacements per atom at 200–250°C. It was clarified that the tensile properties of unirradiated joints and tensile strength of irradiated joints were not changed by the surface roughness condition. However, total elongation of the high surface roughness (type-C) joints was smaller than that of the other joints after neutron irradiation, because diffusion of Cr and Fe into the copper alloy was not uniform compared with that of the other HIP joints. This study shows that a more uniform diffusion region is necessary for HIP joints to be used under neutron irradiation than for unirradiated Cu/stainless steel HIP joints.