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Iwai, Yasunori; Kubo, Hitoshi*; Oshima, Yusuke*; Noguchi, Hiroshi*; Edao, Yuki; Taniuchi, Junichi*
Fusion Science and Technology, 68(3), p.596 - 600, 2015/10
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)We have newly developed the hydrophobic platinum honeycomb catalysts applicable to tritium oxidation reactor since the honeycomb-shape catalyst can decrease the pressure drop. Two types of hydrophobic honeycomb catalyst have been test-manufactured. One is the hydrophobic platinum catalyst on a metal honeycomb. The other is the hydrophobic platinum catalyst on a ceramic honeycomb made of silicon carbide. The fine platinum particles around a few nanometers significantly improve the catalytic activity for the oxidation tritium at a tracer concentration. The hydrogen concentration in the gaseous feed slightly affects the overall reaction rate constant for hydrogen oxidation. Due to the competitive adsorption of hydrogen and water molecules on platinum surface, the overall reaction rate constant has the bottom value. The hydrogen concentration for the bottom value is 100 ppm under the dry feed gas. We have experimentally confirmed the activity of these honeycomb catalysts is as good as that of pellet-shape hydrophobic catalyst. The results support the hydrophobic honeycomb catalysts are applicable to tritium oxidation reactor.
Ando, Masami; Nozawa, Takashi; Hirose, Takanori; Tanigawa, Hiroyasu; Wakai, Eiichi; Stoller, R. E.*; Myers, J.*
Fusion Science and Technology, 68(3), p.648 - 651, 2015/10
Times Cited Count：1 Percentile：12.03(Nuclear Science & Technology)Pressurized tubes of F82H and B-doped F82H irradiated at 573 and 673 K up to 
6dpa have been measured by a laser profilometer. The irradiation creep strain in F82H irradiated at 573 and 673 K was almost linearly dependent on the effective stress level for stresses below 260 MPa and 170 MPa, respectively. The creep strain of 
BN-F82H was similar to that of F82H IEA at each effective stress level except 294 MPa at 573 K irradiation. For 673 K irradiation, the creep strain of some BN-F82H tubes was larger than that of F82H tubes. It is suggested that a swelling caused in each BN-F82H because small helium babbles might be produced by a reaction of B(n, 
) 
Li.
Higashijima, Satoru; Kamada, Yutaka; Barabaschi, P.*; Shirai, Hiroshi; JT-60SA Team
Fusion Science and Technology, 68(2), p.259 - 266, 2015/09
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Someya, Yoji; Tobita, Kenji; Uto, Hiroyasu; Asakura, Nobuyuki; Sakamoto, Yoshiteru; Hoshino, Kazuo; Nakamura, Makoto; Tokunaga, Shinsuke
Fusion Science and Technology, 68(2), p.423 - 427, 2015/09
Times Cited Count：10 Percentile：73.32(Nuclear Science & Technology)The radioactive waste is generated in every replacement of an in-vessel component. Maintenance scheme is to replace the blanket segment and divertor cassette independently, as the lifetime of them is different. The blanket segment consists of some blanket modules mounted to back-plate. Total weight is estimated to amount to about 6,648 ton (1,575 ton of blanket module, 3,777 ton of back-plate, 372 ton of conducting shell and 924 ton of divertor cassette). In base case, main parameters of DEMO reactor are 8.2 m of major radius and 1.35 GW of fusion output. The lifetimes of blanket segment and divertor cassette are assumed to be 2.2 years and 0.6 year, respectively, 52,487 ton wastes is generated in plant life of 20 years. Therefore, there is a concern that a contamination controlled area for the radioactive waste may increase because much the waste is generated in every replacement. In this paper, management scenario is proposed to reduce the radioactive waste. The back-plates and cassette bodies (628 ton) of divertor was reused. As a result, the displacement per atom (DPA) of the back-plates of SUS316L was 0.2 DPA/year and that of the cassette bodies of F82H was 0.6 DPA/year. Therefore, reusing the back-plates and cassette bodies would be possible, if re-welding points are arranged under neutron shielding. It was found that radioactive waste could be reduced to 20%, when tritium breeding materials are recycled. Finally, a design of DEMO building such as a hot cell and temporary storage etc. is proposed.
Edao, Yuki; Hayashi, Takumi; Fukada, Satoshi*
no journal, ,
It is important to understand behavior of tritium transfer in structural material of concrete for estimation of contamination and decontamination in a tritium handling facility. In the present study, tritium permeation through concrete covered with epoxy and urethane paints was measured, and the interface between concrete and their paints was considered to be most effective in the overall tritium permeation process. Results of our investigation for the rate of tritium transfer and properties and conditions between concrete materials and paints will be reported.
