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
Enoeda, Mikio; Tanigawa, Hisashi; Hirose, Takanori; Suzuki, Satoshi; Ochiai, Kentaro; Konno, Chikara; Kawamura, Yoshinori; Yamanishi, Toshihiko; Hoshino, Tsuyoshi; Nakamichi, Masaru; et al.
Fusion Engineering and Design, 87(7-8), p.1363 - 1369, 2012/08
The development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. For the TBM testing and evaluation toward DEMO blanket, the module fabrication technology development by a candidate structural material, reduced activation martensitic/ferritic steel, F82H, is one of the most critical items from the viewpoint of realization of TBM testing in ITER. Fabrication of a real scale first wall, side walls, a breeder pebble bed box and assembling of the first wall and side walls have succeeded. Recently, the real scale partial mockup of the back wall was fabricated. The fabrication procedure of the back wall, whose thickness is up to 90 mm, was confirmed toward the fabrication of the real scale back wall by F82H. This paper overviews the recent achievements of the development of the WCCB TBM in Japan.
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
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.
Nobuta, Yuji*; Yamauchi, Yuji*; Hino, Tomoaki*; Akamaru, Satoshi*; Hatano, Yuji*; Matsuyama, Masao*; Suzuki, Satoshi; Akiba, Masato
Fusion Engineering and Design, 87(7-8), p.1070 - 1073, 2012/08
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
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.
Nobuta, Yuji*; Yokoyama, Kenji; Kanazawa, Jun*; Yamauchi, Yuji*; Hino, Tomoaki*; Suzuki, Satoshi; Ezato, Koichiro; Enoeda, Mikio; Akiba, Masato
Journal of Nuclear Materials, 417(1-3), p.607 - 611, 2011/10
Hino, Tomoaki*; Shibata, Hironobu*; Yamauchi, Yuji*; Nobuta, Yuji*; Suzuki, Satoshi; Akiba, Masato
Journal of Nuclear Materials, 417(1-3), p.713 - 717, 2011/10
Ito, Tatsuya*; Yamauchi, Yuji*; Hino, Tomoaki*; Shibayama, Tamaki*; Nobuta, Yuji*; Ezato, Koichiro; Suzuki, Satoshi; Akiba, Masato
Journal of Nuclear Materials, 417(1-3), p.1147 - 1149, 2011/10
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
Akiba, Masato; Enoeda, Mikio; Tanaka, Satoru*
Fusion Engineering and Design, 85(10-12), p.1766 - 1771, 2010/12
As the primary candidate of ITER Test Blanket Module (TBM) for the first day of ITER operation, development of Water Cooled Solid Breeder (WCSB) TBM has been performed toward the TBM milestones, which are necessary for acceptance of the TBM in ITER for testing from the first day of plasma operation. Regarding the liquid breeder blanket development, universities and NIFS are conducting the development. This paper overviews the recent achievements of the TBMs and DEMO blankets.
Hirose, Takanori; Ando, Masami; Ogiwara, Hiroyuki*; Tanigawa, Hiroyasu; Enoeda, Mikio; Akiba, Masato
Fusion Engineering and Design, 85(5), p.809 - 812, 2010/08
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.
Tsuru, Daigo; Enoeda, Mikio; Hirose, Takanori; Tanigawa, Hisashi; Ezato, Koichiro; Yokoyama, Kenji; Dairaku, Masayuki; Seki, Yohji; Suzuki, Satoshi; Mori, Kensuke*; et al.
Fusion Science and Technology, 56(2), p.875 - 882, 2009/08
As the primary candidate of ITER Test Blanket Module (TBM) for the first day of ITER operation, development of Water Cooled Solid Breeder (WCSB) TBM has been performed toward the TBM milestones, which are necessary for acceptance of the TBM in ITER for testing from the first day of plasma operation. Milestones of ITER TBMs prior to the installation consist of milestones on safety assessment, module qualification and design integration in ITER. This paper overviews the recent achievements for preparation of the WCSB TBM for ITER day-1 operation, toward the TBM milestones.
Tanigawa, Hisashi; Tanaka, Yuichiro*; Enoeda, Mikio; Akiba, Masato
Journal of Nuclear Science and Technology, 46(6), p.553 - 556, 2009/06
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.
Tsuru, Daigo; Tanigawa, Hisashi; Hirose, Takanori; Mori, Kensuke*; Seki, Yohji; Enoeda, Mikio; Ezato, Koichiro; Suzuki, Satoshi; Nishi, Hiroshi; Akiba, Masato
Nuclear Fusion, 49(6), p.065024_1 - 065024_8, 2009/06
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
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.
Akiba, Masato; Enoeda, Mikio; Tsuru, Daigo; Tanigawa, Hisashi; Hirose, Takanori; Mori, Kensuke*; Seki, Yohji; Ezato, Koichiro; Suzuki, Satoshi; Nishi, Hiroshi; et al.
Fusion Engineering and Design, 84(2-6), p.329 - 332, 2009/02
One of the most important missions of ITER is to provide a test bed for breeding blanket modules, which are called as Test Blanket Module (TBM). JAEA has been extensively developing a Water-Cooled Solid Breeder Test Blanket Module (WCSB TBM) for ITER. This paper describes results of recent R&D activities on WCSB TBM in JAEA. JAEA developed fabrication technology of F82H rectangular cooling tubes, and has successfully fabricated the near-full scale first wall mock-up of WCSB TBM by Hot Isostatic Press (HIP) technique, which is fully made of F82H. The mock-up has been high-heat flux tested in the DATS facility in JAEA, which is an ion beam test facility. The inlet temperature of the cooling water is about 280 C with 15 MPa, which is almost the same as the WCSB TBM design conditions. The mock-up has endured a heat load of 0.5 MW/m, 30 s for 80 thermal cycles. Neither hot spots nor thermal degradation have been observed.
Hirose, Takanori; Enoeda, Mikio; Ogiwara, Hiroyuki; Tanigawa, Hiroyasu; Akiba, Masato
Fusion Engineering and Design, 83(7-9), p.1176 - 1180, 2008/12
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.
Tsuru, Daigo; Enoeda, Mikio; Akiba, Masato
Fusion Engineering and Design, 83(7-9), p.1238 - 1243, 2008/12
One-dimensional analyses are carried out for the three representative event sequences about heatup of WCSB TBM. For the event sequence of loss of cooling of the TBM during plasma operation, the requirement to the TBM design becomes apparent that no cooling pipe rupture can be guaranteed under the predicted highest temperature condition to prevent the activation of the Be-HO chemical reaction under the high temperature condition. For the event sequence of ingress of coolant into the TBM during plasma operation, the requirement for the cooling system of TBM becomes apparent that the cooling system for the TBM should be designed to continue its operation against partial loss of coolant due to the ingress of coolant. For the loss of off-site power after the ingress of coolant, it is confirmed that the event converges.
Tsuru, Daigo; Enoeda, Mikio; Akiba, Masato
Fusion Engineering and Design, 83(10-12), p.1747 - 1752, 2008/12
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.
Ezato, Koichiro; Suzuki, Satoshi; Dairaku, Masayuki; Akiba, Masato
Fusion Engineering and Design, 83(7-9), p.1097 - 1101, 2008/12
As part of development of Plasma-Facing Components (PFCs) for fusion machines, JAEA has been developing high performance cooling tubes with pressurized water flow. Along this line, a cooling tube with a helical triangular fin on its inner surface has been proposed recently for application to a fusion DEMO to enhance heat removal. Since the fin can be machined by a simple mechanical threading, this tube is called as a screw tube. Divertor cooling conditions in the DEMO design in JAEA are envisaged at the pressure of 4 MPa and the outlet temperature of 200C to improve thermal efficiency of power generation. In the this study, effect of subcooling on critical heat flux (CHF) of the screw tube has been investigated under DEMO-relevant condition with the local pressure of 4 MPa and the inlet coolant temperature up to 180C. A test sample is the screw tube made of pure Cu instead of F82H, a candidate material of the DEMO divertor. The results show that the ICHF values of the screw tube remains more than double values of the smooth at the inlet coolant temperature of 180C, although temperature rise of the cooling water with 140 K leads to reduction of ICHF by almost half compared with those values at room temperature.