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Aihara, Jun; Ueta, Shohei; Yasuda, Atsushi*; Takeuchi, Hitoshi*; Mozumi, Yasuhiro*; Sawa, Kazuhiro; Motohashi, Yoshinobu*
Materials Transactions, 50(11), p.2631 - 2636, 2009/11
Times Cited Count：8 Percentile：45.88(Materials Science, Multidisciplinary)The ZrC coating layer has been fabricated using the bromide process at JAEA. The coated particles with IPyC layers reported in a previous study were annealed at around 1800
C for 1h, under which compact sintering will be done in a practical process, in order to study effects of the heat treatment (annealing) on their microstructure evolution. Then the microstructures of the ZrC layers in the cases (batches) of C/Zr = 1.11 and 1.35 were characterized by means of TEM and STEM. Certain changes in the shape and size of voids or free carbons region caused by the heat treatment were found in the cases of both batches. After the heat treatment, the voids or free carbons region have shown a clod like feature with diameters of 50 to 100 nm. The grain growth of ZrC was also observed in both cases: In the ZrC layer with C/Zr = 1.11, the fibrous carbons grew as of to stand from the PyC to ZrC layers on some places in the IPyC/ZrC boundary.
Mozumi, Yasuhiro; Ueta, Shohei; Aihara, Jun; Sawa, Kazuhiro
JAEA-Technology 2008-086, 16 Pages, 2009/02
JAEA-Technology-2008-086.pdf:4.0MB
Fuel for the Very High Temperature Reactor (VHTR) is required to be used under severer irradiation conditions and higher operational reactor temperatures than those of present high temperature gas cooled reactors. Japan Atomic Energy Agency has developed the advanced silicon carbide (SiC) -coated fuel particles having thicker layer thicknesses, and zirconium carbide (ZrC)-coated particles that are expected to preserve their integrity at higher temperatures and burnup conditions than current conventional coated fuel particles. These particles have been fabricated successfully in order to perform irradiation tests at experimental reactors. This paper is summarized fabrication data of irradiation samples.
Aihara, Jun; Ueta, Shohei; Yasuda, Atsushi; Ishibashi, Hideharu; Mozumi, Yasuhiro; Sawa, Kazuhiro; Motohashi, Yoshinobu*
Journal of the American Ceramic Society, 92(1), p.197 - 203, 2009/01
Times Cited Count：7 Percentile：42.38(Materials Science, Ceramics)The ZrC coating layer was fabricated with bromide process at JAEA. In a later stage of the project, we have successfully kept nominal deposition temperature almost constant. Microstructures of the ZrC layers, of which nominal deposition temperatures were able to measure, were characterized by means of TEM and STEM and the results were compared and discussed with those obtained for different batches including those reported in a previous study. The ZrC grains were oriented in the ZrC layers deposited at about 1630 K. This feature was rather different from that reported in the previous study. The formation of fairly different PyC structures was found on the PyC/ZrC boundary as well as around the pores existing near the boundary. Fibrous carbons were observed on the PyC/ZrC boundary produced in a batch deposited at a higher temperature (nominal temperature was 1769 K); no such fibrous carbons were found in a batch deposited at a lower temperature (nominal temperature was 1632 K).
Ueta, Shohei; Aihara, Jun; Yasuda, Atsushi; Ishibashi, Hideharu; Mozumi, Yasuhiro; Sawa, Kazuhiro; Minato, Kazuo
Hyomen, 46(4), p.222 - 232, 2008/04
Japan Atomic Energy Agency (JAEA) is developing the zirconium carbide (ZrC) coated fuel particle which has better refractoriness and chemical stability than the conventional silicon carbide (SiC) coated fuel particle. In the present study, ZrC coating tests were carried out by the enlarged 200 g-scale ZrC coater comparing with the previous study. Finally, the stoichiometric ZrC layer was successfully fabricated by obtaining relationships between properties of ZrC, coating temperature and batch size through coating tests. In addition, not only inspection methods for coating thickness and density, but also treatment technique to remove pyrocarbon (PyC) layer were developed in order to evaluate the quality of the ZrC coated fuel particle. Present R&D will contribute to the practicability of the ZrC coated fuel particle as a fuel for the advanced high temperature gas cooled reactor such as the Very High Temperature Reactor (VHTR).
Sakaba, Nariaki; Tachibana, Yukio; Shimakawa, Satoshi; Ohashi, Hirofumi; Sato, Hiroyuki; Yan, X.; Murakami, Tomoyuki; Ohashi, Kazutaka; Nakagawa, Shigeaki; Goto, Minoru; et al.
JAEA-Technology 2008-019, 57 Pages, 2008/03
JAEA-Technology-2008-019.pdf:8.59MB
The small-sized and safe cogeneration High Temperature Gas-cooled Reactor (HTGR) that can be used not only for electric power generation but also for hydrogen production and district heating is considered one of the most promising nuclear reactors for developing countries where sufficient infrastructure such as power grids is not provided. Thus, the small-sized cogeneration HTGR, named High Temperature Reactor 50-Cogeneration (HTR50C), was studied assuming that it should be constructed in developing countries. Specification, equipment configuration, etc. of the HTR50C were determined, and economical evaluation was made. As a result, it was shown that the HTR50C is economically competitive with small-sized light water reactors.
Aihara, Jun; Ueta, Shohei; Mozumi, Yasuhiro; Sato, Hiroyuki; Motohashi, Yoshinobu*; Sawa, Kazuhiro
Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM), p.416 - 422, 2007/09
In high temperature gas-cooled reactors (HTGRs), coated particles are used as fuels. For upgrading HTGR technologies, present SiC coating layer which is used as the 3rd layer could be replaced with ZrC coating layer which have much higher temperature stability in addition to higher resistance to chemical attack by fission product palladium than the SiC coating layer. The ZrC layer could deform plastically at high temperatures. Therefore, the Japan Atomic Energy Agency modified an existing pressure vessel failure fraction calculation code to treat the plastic deformation of the 3rd layer in order to predict failure fraction of ZrC coated particle under irradiation. Finite element method is employed to calculate the stress in each coating layer. The pressure vessel failure fraction of the coated fuel particles under normal operating condition of GTHTR300C is calculated by the modified code. The failure fraction is evaluated as low as 3.5
10
.
Sawa, Kazuhiro; Aihara, Jun; Ueta, Shohei; Mozumi, Yasuhiro; Kato, Shigeru*; Takahashi, Masashi*
no journal, ,
In the field of HTGR fuel, JAEA has carried out a lot of research and development works in the frame of the High Temperature Engineering Test Reactor (HTTR) Project. The fuel fabrication technologies were developed with the collaboration of the Nuclear Fuel Industry Co. Ltd.. Fuel performance was investigated by Oarai Gas Loop-1 and capsule irradiation tests, which were installed at the Japan Materials Test Reactor. The fuel performance and fission product behavior are under investigation through the HTTR operation. For upgrading of HTGR technologies, JAEA has also developed an extended burnup TRISO-coated fuel particle, and an advanced type of coated fuel particle. This paper provides experiences and present status of research and development works for the HTGR fuel.
