Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Yamaki, Tatsunori*; Abe, Yutaka*; Kaneko, Akiko*; Segawa, Tomoomi; Kawaguchi, Koichi; Yamada, Yoshikazu; Fujii, Kanichi*
Journal of Nuclear Science and Technology, 52(2), p.241 - 250, 2015/02
Times Cited Count：3 Percentile：25.85(Nuclear Science & Technology)In the Microwave Heating de-nitration method developed in Japan, a mixed solution of uranyl nitrate and plutonium nitrate recovered from the spent fuel in the reprocessing plant is converted directly to mixed oxide (MH-MOX) powder. This MH-MOX powder is utilized to fabricate MOX fuel with UO
powder for FBR. The MH method is accompanied with transient boiling phenomena such as overflow and flushing. Toward high-speed and high-capacity conversion by MH-method in the future, it is required to avoid overflow and flushing and to understand optimal design conditions for design and operation. At the first step for these objectives, basic knowledge of transient boiling phenomena by the MH-method has been acquired with using distilled water. It was observed that generation of singular bubble triggered flushing and distilled water just before flushing was superheated by a temperature 10 degrees centigrade higher than boiling temperature. Based on these results, it is clarified that the occurrence criteria of flushing correlate with absorbed power in the water and released power from the water surface.
Fukui, Kunihiro*; Igawa, Yusuke*; Arimitsu, Naoki*; Suzuki, Masahiro; Segawa, Tomoomi; Fujii, Kanichi*; Yamamoto, Tetsuya*; Yoshida, Hideto*
Chemical Engineering Journal, 211-212, p.1 - 8, 2012/11
Times Cited Count：13 Percentile：41.13(Engineering, Environmental)The process for synthesizing metallic oxide powders by the microwave denitration method was investigated using hexahydrated nickel nitrate and trihydrated copper nitrate aqueous solutions, and the electrical field and the temperature distributions in the reactor were numerically simulated. Although CuO powder can be obtained from a trihydrated copper nitrate aqueous solution by the microwave denitration method, a hexahydrated nickel nitrate aqueous solution cannot be heated up to over 270 
C by microwave irradiation. It was also found that the reaction routes for microwave heating are the same as those for conventional external heating. This finding indicates that the success of producing oxide particles by microwave denitration depends not only on the microwave absorptivity of the intermediate and the metallic oxide, but also on the temperature difference.
Imai, Suguru*; Nakajima, Yuki*; Taguchi, Kenji*; Kashiwa, Tatsuya*; Kitazawa, Toshihide*; Suzuki, Masahiro; Segawa, Tomoomi; Fujii, Kanichi
Proceedings of 2011 International Symposium on Antennas and Propagation (ISAP 2011) (USB Flash Drive), 4 Pages, 2011/10
As a part of the nuclear fuel cycle in Japan, the mixed oxide (MOX) fuels are produced through the microwave heating of the Pu/U mixed nitrate solution obtained from spent fuels. This paper investigated the electric power absorption of the solid Pu/U mixed nitrate medium in a cylindrical oven cavity and the effect of the input polarized waves. The numerical simulations have revealed that the incidence of the circularly polarized wave improves the uniformity of the absorbed power of the medium placed in the cylindrical cavity.
Kurita, Tsutomu; Kato, Yoshiyuki; Yoshimoto, Katsunobu; Suzuki, Masahiro; Kihara, Yoshiyuki; Fujii, Kanichi
Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.94 - 102, 2009/09
With regard to advanced MOX fuel fabrication, a new concept in which one vessel especially designed to meet microwave de-nitration is utilized also for crushing and for granulation, without organic lubricant nor powder transfer across the processes, was introduced for innovative MOX powder production. In order to realize this concept, two attempts were made: A specially designed three blade impeller coupled with auxiliary blade. A uniquely shaped mixing blade coupled with an auxiliary blade having auto-orbital hybrid rotation. The mixing blade promotes the growth of particles, whereas the auxiliary blade suppresses the overgrowth by chopping larger particles. These granulators use a little water as binder. As a result, major diameter of granule 400-1000 micron and flow-ability 82-85 was obtained with fine WO
model powder. Therefore, a prospect to satisfy both desirable powder properties and simplified nuclear material production was opened, as well as improvement of working efficiency and cut down on costs.
Suzuki, Masahiro; Ishii, Katsunori; Yamamoto, Takuma; Kihara, Yoshiyuki; Kato, Yoshiyuki; Kurita, Tsutomu; Yoshimoto, Katsunobu; Fujii, Kanichi
Proceedings of Global Congress on Microwave Energy Applications (GCMEA 2008/MAJIC 1st), p.501 - 504, 2008/08
The natural resources, oil and uranium, would dry up around the midway of this century. FBR cycle most probably rescues this difficult situation. Mass production of MOX fuel for FBR, therefore, is the supreme subject to Japanese energy strategy. For this subject, we are attacking with Microwave heating technology. Up to present, we have succeeded to produce excellent PuO/UO bulk, 2 kgMOX/batch, advancing toward the mass production target, 5 kgU/h for one batch.
Ishii, Katsunori; Suzuki, Masahiro; Kihara, Yoshiyuki; Fujii, Kanichi*
Funtai Kogakkai-Shi, 42(7), p.472 - 477, 2005/00
To optimize sphere-pac fuel pin fabrication process, internal structure of fuel pin under small particles infiltration process was observed by micro focus X-ray CT system. Some small particles block the space among large particles. Small particles arrive at the bottom of fuel column, and fill the space among large particles, and form completed packing layer. Sphere-pac process progresses with growth of the layer from bottom to top of the column. A unique layer is formed around the top of fuel column shot time after starting vibration. Small particles completely intrude between large particles and pin wall in the layer. The structure never changes after completion of small particles infiltration process. The formation of the unique layer can be qualitatively explained by simulation.
Ishii, Katsunori; Kihara, Yoshiyuki; Fujii, Kanichi*
Japanese Journal of Applied Physics, 44(4A), p.1955 - 1956, 2005/00
Times Cited Count：1 Percentile：4.7(Physics, Applied)A vibrational sphere-pack technology employing large and small particles is discussed in the manner of simulation to the fabrication of atomic fuel pin, by four kinds of model particles.The infiltration property is almost free from the sort of materials and the weifht density.From this result,the feasibility to mix the heavy metallic uranium as the getter for absorbing oxygen, thereby prevents the oxidization of fuel pin is suggested.
Fujii, Kanichi*
JNC TY8400 2002-008, 23 Pages, 2002/05
JNC-TY8400-2002-008.pdf:2.59MB
None
(1
) and trapping temperature in chemical oxygen iodine laserKitatani, Fumito; Fujii, Kanichi*
Reza Kenkyu, 25(9), p.654 - 657 , 1997/00
The chemical oxygen iodine laser (COIL) which oscillates 1315 nm laser line was investigated from a riewpoint of high power transmission with optical fiber. The generation and vanishing states of O(1) molecules which take the key role for pumping of iodine vapor atoms ware pursued. The behavior of water vapor,which is also producedtogether with O(1) molecules in the mixing process of chemical fuels
Kato, Yoshiyuki; Kurita, Tsutomu; Matsumoto, Masaki; Suzuki, Masahiro; Ishii, Katsunori; Yamamoto, Takuma; Kihara, Yoshiyuki; Yoshimoto, Katsunobu; Fujii, Kanichi
no journal, ,
An earlier accomplishment of FBR(fast breeder reactor) fuel cycle is the supreme subject from the point of view on the protection of environment by suppressing the green house effect as well as saving the oil. Microwave heating (MH) is employed as the MOX (mixed oxides U-Pu) production process in the main stream of FBR cycle. Thus, we are the optimization of MH method. We will describe the practical work of MOX fuel production which recycles the consumed nuclear fuel containing both U and Pu. The MH is employed to solidify the mixed solution by evaporating nitric acid and water. We call this processing de-nitration. The physical, mechanical, and chemical characteristics of the products are analyzed, being thereby discussed the contribution of the MH technology to the MOX fuel production. And, optimization of MH is discussed from the view point of design of MH oven, regulation of MH power, and combination with several auxiliary heating sources.
Suzuki, Masahiro; Ishii, Katsunori; Kihara, Yoshiyuki; Kurita, Tsutomu; Yoshimoto, Katsunobu; Okita, Takatoshi; Kashimura, Motoaki; Kato, Masato; Namekawa, Takashi; Fujii, Kanichi
no journal, ,
In FaCT project, we have set major six technologies for success of simplified pellet fuel fabrication. Our schedule on the technical fundamental technology should be completed by 2010, being transferred to the development of a technology for tele-command operation of mass production and facility maintenance until 2015. In this time, we will report current states of FaCT project as well as future plan.
Suzuki, Shota*; Kaneko, Akiko*; Abe, Yutaka*; Suzuki, Masahiro; Segawa, Tomoomi; Fujii, Kanichi
no journal, ,
The influences of vessel, solution and heating properties for boiling behavior were evaluated to clear them in the electro-magnetic wave (microwave) heating of the de-nitrate conversion process of nuclear fuel cycle. Boiling and fluid behavior of solution were observed by the high speed video camera, the temperature of solution level were measured by radiation thermography, and the temperature of the vessel surface was measured by thermography. The temperature of solution level was 103.2 degree, which showed that the solution was overheated. The corrected temperature on the vessel surface measured by thermography was 105.8 degree. It is expected that the inner temperature of solution is higher than that of vessel surface. It is considered that the energy of microwave concentrates at the core of solution, and flushing is leaded by generating the uniform nucleation according to overheating.
Kawaguchi, Koichi; Segawa, Tomoomi; Ishii, Katsunori; Suzuki, Masahiro; Fujii, Kanichi
no journal, ,
In a nuclear fuel cycle, uranium-plutonium mixed oxide (MOX) is produced from the reprocessing solution of spent nuclear fuel. The microwave heating method is applied to remove water and nitric acid from nitrate solution, and oxide is obtained. In our group, it has been developed to enlarge capacity of microwave heating denitration for mass production system. For large target to be heated, unequal heating becomes likely to occur and uniform heating has been assigned as issue. We performed microwave heating of the starch syrup to try visualization of the heating region based on optical image and thermography, and difference in distributions of heating region caused by cavity structure was compared.
Segawa, Tomoomi; Suzuki, Masahiro; Fujii, Kanichi; Igawa, Yusuke*; Arimitsu, Naoki*; Yamamoto, Tetsuya*; Fukui, Kunihiro*; Yoshida, Hideto*
no journal, ,
The synthesis process of the denitration reaction by the microwave heating method was investigated using a nickel nitrate (Ni(NO)) aqueous solution. NiO powder cannot be obtained from Ni(NO) aqueous solution by the microwave heating method because of low microwave absorption of the intermediate obtained from nitrate aqueous solution. In the present work, it was showed that Ni(NO) aqueous solution with 6.0 g of NiO powder as a microwave absorber can be completely converted to NiO powder by microwave heating. NiO powder promotes the denitration reaction, and reduces the required reaction time with increasing the amount of NiO powder. Furthermore the adiabator was set around the reactor in order to equalize the temperature distribution in the reactor. It was also found that the denitration efficiency of Ni(NO) aqueous solution to NiO powder can be improved by using the adiabator when the center of the reactor has the same temperature.
Yamaki, Tatsunori*; Kaneko, Akiko*; Abe, Yutaka*; Segawa, Tomoomi; Kawaguchi, Koichi; Yamada, Yoshikazu; Suzuki, Masahiro; Fujii, Kanichi*
no journal, ,
To use recovered uranium and plutonium as raw material of nuclear fuel, reprocessing solution (uranium and plutonium mixed nitrate solution) of the spent nuclear fuel is converted to uranium and plutonium mixed oxide (MOX) powder. Microwave heating direct denitration method is one of such methods to convert nitrate solution to MOX powder. The cylindrical denitration vessel can be expected to realize high-speed and high-capacity processing against traditional shallow vessel. Flushing and overflow phenomena of solution have been confirmed in cylindrical vessel. The research was conducted in order to clarify mechanism of the flushing and overflow phenomena during microwave heating. It was found that there was tendency of flushing in the case of short vessel diameter and high initial water level when magnetron power was constant. It was confirmed that the liquid temperature just before flushing was superheat.
