Development of high-grade VPS-tungsten coatings on F82H reduced activation steel

Tokunaga, Tomonori*; Watanabe, Hideo*; Yoshida, Naoaki*; Nagasaka, Takuya*; Kasada, Ryuta*; Lee, Y.-J.*; Kimura, Akihiko*; Tokitani, Masayuki*; Mitsuhara, Masatoshi*; Hinoki, Tatsuya*; et al.

Journal of Nuclear Materials, 442(1-3), p.S287 - S291, 2013/11

https://doi.org/10.1016/j.jnucmat.2012.11.004

Effect of sweep gas species on tritium release behavior from lithium titanate packed bed during 14MeV neutron irradiation

Kawamura, Yoshinori; Ochiai, Kentaro; Hoshino, Tsuyoshi; Kondo, Keitaro*; Iwai, Yasunori; Kobayashi, Kazuhiro; Nakamichi, Masaru; Konno, Chikara; Yamanishi, Toshihiko; Hayashi, Takumi; et al.

Fusion Engineering and Design, 87(7-8), p.1253 - 1257, 2012/08

https://doi.org/10.1016/j.fusengdes.2012.02.125

Tritium generation and recovery study on lithium ceramic packed bed was started by use of FNS in JAEA. Lithium titanate was selected as tritium breeding material. In this work, the effect of sweep gas species on tritium release behavior was investigated. In case of sweep by helium with 1% of hydrogen, tritium in water form was released sensitively corresponding to the irradiation. This is due to existence of the water vapor in the sweep gas. On the other hand, in case of sweep by dry helium, tritium in gaseous form was released first, and release of tritium in water form was delayed and was gradually increased.

Recent status of fabrication technology development of water cooled ceramic breeder test blanket module in Japan

Hirose, Takanori; Tanigawa, Hisashi; Yoshikawa, Akira; Seki, Yohji; Tsuru, Daigo; Yokoyama, Kenji; Ezato, Koichiro; Suzuki, Satoshi; Enoeda, Mikio; Akiba, Masato

Fusion Engineering and Design, 86(9-11), p.2265 - 2268, 2011/10

https://doi.org/10.1016/j.fusengdes.2011.02.024

As one of the most important fabrication technologies of the WCCB TBM, Hot Isostatic Pressing (HIP) joining technology was selected to fabricate the first wall with built-in cooling channel structure made of reduced activation martensitic/ferritic steel, F82H. By using developed HIP technology, a real scale TBM first wall mockup was successfully fabricated. High heat flux test of the fabricated mockup showed the feasibility to with the equivalent conditions of the WCCB TBM operation. The breeder pebble box was successfully fabricated with thin wall cooling pipes and thin plate sleds by Laser welding. With respect to the side walls with built in cooling channels were also fabricated using drilling technology. Assembling of the first wall and side walls is one of the critical fabrication processes of the fabrication of the TBM structure. By using a F82H first wall mockup and side wall mockups, assembling process was demonstrated successfully by Electron Beam welding.

Deuterium ion irradiation for tritium breeding material and evaluation for tritium inventories in test blanket module and blanket of a demonstration reactor

Hino, Tomoaki*; Shibata, Hironobu*; Yamauchi, Yuji*; Nobuta, Yuji*; Suzuki, Satoshi; Akiba, Masato

Journal of Nuclear Materials, 417(1-3), p.713 - 717, 2011/10

https://doi.org/10.1016/j.jnucmat.2010.12.124

Application of tritium tracer techniques to observation of hydrogen on surface and in bulk of F82H

Otsuka, Teppei*; Tanabe, Tetsuo*; Tokunaga, Kazutoshi*; Yoshida, Naoaki*; Ezato, Koichiro; Suzuki, Satoshi; Akiba, Masato

Journal of Nuclear Materials, 417(1-3), p.1135 - 1138, 2011/10

https://doi.org/10.1016/j.jnucmat.2010.12.101

Interfacial properties of HIP joints between beryllium and reduced activation ferritic/martensitic steel

Hirose, Takanori; Ando, Masami; Ogiwara, Hiroyuki*; Tanigawa, Hiroyasu; Enoeda, Mikio; Akiba, Masato

Fusion Engineering and Design, 85(5), p.809 - 812, 2010/08

https://doi.org/10.1016/j.fusengdes.2010.06.002

In this work, the interfacial properties of Be-reduced activation ferritic/martensitic steel (RAFMs) joints were investigated for the first wall of an ITER test blanket module (TBM). The joints were produced by the solid state hot isostatic pressing (HIP) method. Chromium (Cr) was used as a diffusion barrier with a thickness of 1 micron or 10 microns, formed by plasma vapor deposition on the Be surface. The HIPping was conducted at 1023 K and 1233 K. The temperatures are standard normalizing and tempering temperatures of F82H. EPMA showed the Cr layer effectively worked as a diffusion barrier at 1023 K. However, for the F82H/Be interface which underwent HIP at 1233 K followed by tempering a Be rich layer was formed. Bend tests revealed that a thin Cr layer and low temperature HIP is preferable.

Thermal conductivity measurement with silica-coated hot wire for LiSiO pebble bed

Tanigawa, Hisashi; Tanaka, Yuichiro*; Enoeda, Mikio; Akiba, Masato

Journal of Nuclear Science and Technology, 46(6), p.553 - 556, 2009/06

https://doi.org/10.3327/jnst.46.553

Effective thermal conductivity of a LiSiO pebble bed was measured by the hot wire method. The bare and the silica-coated Nichrome heaters were used as the hot wire. At 975 K, the effective thermal conductivity was not measured correctly by the bare hot wire. This is caused by that the electrical signal of the bare thermocouple is distorted due to electrical conductivity of LiSiO. Using the silica-coated hot wire, the effective thermal conductivity can be measured at temperatures ranging from room temperature to 975 K. The effect of the coating layer on the measured effective thermal conductivity was estimated to be small and corresponded to the experimental data. The hot wire method with silica-coating can be applied to the other ceramic breeder materials.

R&Ds of a LiTiO pebble bed for a test blanket module in JAEA

Tanigawa, Hisashi; Hoshino, Tsuyoshi; Kawamura, Yoshinori; Nakamichi, Masaru; Ochiai, Kentaro; Akiba, Masato; Ando, Masami; Enoeda, Mikio; Ezato, Koichiro; Hayashi, Kimio; et al.

Nuclear Fusion, 49(5), p.055021_1 - 055021_6, 2009/05

https://doi.org/10.1088/0029-5515/49/5/055021

This paper presents recent achievements of the research activities for the TBM being developed in JAEA, focusing on the pebble bed of the tritium breeder materials and tritium behaviour. For the breeder material, the chemical stability of LiTiO has been improved by LiO additives. In order to analyze the pebble bed behaviour, thermo-mechanical properties of the LiTiO pebble bed has been experimentally obtained. In order to verify nuclear properties of the pebble bed, the activation foil method has been proposed and a preliminary experiment has been conducted. For the tritium behaviour, the chemical densified coating method has been well developed and tritium recovery system has been modified taking account of the design change of the TBM.

Structural material properties and dimensional stability of components in first wall components of a breeding blanket module

Hirose, Takanori; Enoeda, Mikio; Ogiwara, Hiroyuki; Tanigawa, Hiroyasu; Akiba, Masato

Fusion Engineering and Design, 83(7-9), p.1176 - 1180, 2008/12

https://doi.org/10.1016/j.fusengdes.2008.06.023

This paper summarize the fabrication process of the first wall structure and provides the material properties of the structural material F82H and dimensional stability of the components through whole of the process. A cold-rolling process introduced typical stretched rolling structure and ferrite/martensite dual phase structure, which lead reduction in strength. These anisotropic microstructural features were successfully recovered by optimized HIP process at 1373 K. As for dimensional stability of the components, a full-scale mockup has been developed with F82H tubes and plates. The HIPped mockup demonstrated good accordance with a design drawing. The dimensions of wall thickness and cooling channels were to size even after HIP. According to these results, the fabrication process does not degrade the material properties and demonstrates good dimensional accuracy and stability of the FW structure.

Recent progress in safety assessments of Japanese water-cooled solid breeder test blanket module

Tsuru, Daigo; Enoeda, Mikio; Akiba, Masato

Fusion Engineering and Design, 83(10-12), p.1747 - 1752, 2008/12

https://doi.org/10.1016/j.fusengdes.2008.06.056

This reports presents summary of safety assessment activities of the Japanese WCSB TBM. Nuclear analyses have been carried out to calculate neutron flux, tritium breeding ratio, nuclear heat, decay heat and induced activity of radioactive waste are calculated. For the purpose of evaluation of occupational radiolysis exposure, RI inventories in each component are estimated. FMEA has been carried out to identify the PIEs, i.e., the representative events that need safety evaluation. The PIEs are summarized into three groups, i.e., release of RI, pressurization and heatup. With respect to PIEs about release of RI, the maximum released RI is evaluated for three RI inventories, i.e., RI in VV (tritium and radio-activated dust), RI in purge gas (tritium) and RI in coolant (tritium and Active Corrosion Products (ACP)). With respect to PIEs about pressurization, the PIEs of pressurization of the compartment nearby the pipes of cooling system are evaluated by numerical analyses.