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Journal Articles

Study on optimizing microwave heating denitration method and powder characteristics of uranium trioxide

Segawa, Tomoomi; Kawaguchi, Koichi; Kato, Yoshiyuki; Ishii, Katsunori; Suzuki, Masahiro; Fujita, Shunya*; Kobayashi, Shohei*; Abe, Yutaka*; Kaneko, Akiko*; Yuasa, Tomohisa*

Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 9 Pages, 2019/05

A solution of plutonium nitrate and uranyl nitrate is converted into a mixed oxide by microwave heating denitration method. In the present study, for improving the efficiency of microwave heating and achieving high-temperature uniformity to produce homogeneous UO$$_{3}$$ powder, the microwave heating test of potassium chloride and uranyl nitrate solution, and numerical simulation analysis were conducted. The potassium chloride agar was adjusted to the dielectric loss, which is close to that of the uranyl nitrate solution and the optimum support table height was estimated to be 50 mm for denitration of the uranyl nitrate solution by microwave heating. The adiabator improved the efficiency of microwave heating denitration. Moreover, the powder yield was improved by using the adiabator owing to ease of scraping of the denitration product from the bottom of the denitration vessel.

Journal Articles

Depth profile and inventory of $$^{36}$$Cl in soil near the Fukushima Dai-ichi Nuclear Power Plant

Ota, Yuki*; Sueki, Keisuke*; Sasa, Kimikazu*; Takahashi, Tsutomu*; Matsunaka, Tetsuya*; Matsumura, Masumi*; Tosaki, Yuki*; Honda, Maki*; Hosoya, Seiji*; Takano, Kenta*; et al.

JAEA-Conf 2018-002, p.99 - 102, 2019/02

no abstracts in English

Journal Articles

Development of novel alumina adsorbent applying mesoporous process

Fukumitsu, Nobuyoshi*; Yamauchi, Yusuke*; Saptiama, I.*; Ariga, Katsuhiko*; Hatano, Kentaro*; Kumada, Hiroaki*; Fujita, Yoshitaka; Tsuchiya, Kunihiko

Isotope News, (760), p.15 - 18, 2018/12

no abstracts in English

Journal Articles

Mechanism of flashing phenomena by microwave heating and influence of high dielectric constant solution

Fujita, Shunya*; Abe, Yutaka*; Kaneko, Akiko*; Yuasa, Tomohisa*; Segawa, Tomoomi; Kato, Yoshiyuki; Kawaguchi, Koichi; Ishii, Katsunori

Proceedings of 11th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-11) (Internet), 7 Pages, 2018/11

Mixed uranium oxide and plutonium oxide powder is produced from uranyl nitrate and plutonium nitrate mixed solution by the microwave heating denitration method in the spent fuel reprocessing process. Since the microwave heating method is accompanied by a boiling phenomenon, it is necessary to fully grasp the operating conditions in order to avoid flashing and spilling in the mass production of denitrification technology for the future. In this research, it was clarified that the heat transfer coefficient became lower as the dielectric constant increased. The dominant factor of the blowing up phenomena is supposed to be generation of the innumerable bubble rather than bubble's growth.

Journal Articles

Mechanism of flashing phenomena induced by microwave heating

Fujita, Shunya*; Abe, Yutaka*; Kaneko, Akiko*; Yuasa, Tomohisa*; Segawa, Tomoomi; Yamada, Yoshikazu; Kato, Yoshiyuki; Ishii, Katsunori

Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 8 Pages, 2018/07

Mixed uranium oxide and plutonium oxide powder is produced from uranyl nitrate and plutonium nitrate mixed solution by the microwave heating denitration method in the spent fuel reprocessing process. Since the microwave heating method is accompanied by a boiling phenomenon, it is necessary to fully grasp the operating conditions in order to avoid flashing and spilling in the mass production of denitrification technology for the future. In this research, it was confirmed that a potassium chloride aqueous solution as a simulant of uranyl nitrate aqueous solution with high dielectric loss cause loss of microwave at the solution surface as the dielectric loss increased with the increase of KCl concentration by experimental and electromagnetic field analysis, and revealed that the change in the heating condition affects the generation of flushing.

Journal Articles

Visualization study on droplet-entrainment in a high-speed gas jet into a liquid pool

Sugimoto, Taro*; Saito, Shimpei*; Kaneko, Akiko*; Abe, Yutaka*; Uchibori, Akihiro; Ohshima, Hiroyuki

Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 7 Pages, 2018/07

A computational fluid dynamics code for a sodium-water reaction phenomenon in a steam generator of sodium-cooled fast reactors has been developed. In order to provide the data for validation of this code, the visualization experiment on liquid droplet entrainment in the high-pressure air jet submerged in the water pool was carried out. The experiment successfully elucidated the behavior, such as atomization of the relatively large diameter liquid droplet generated from the gas-liquid interface.

Journal Articles

Template-free fabrication of mesoporous alumina nanospheres using post-synthesis water-ethanol treatment of monodispersed aluminium glycerate nanospheres for molybdenum adsorption

Saptiama, I.*; Kaneti, Y. V.*; Suzuki, Yoshitaka; Tsuchiya, Kunihiko; Fukumitsu, Nobuyoshi*; Sakae, Takeji*; Kim, J.*; Kang, Y.-M.*; Ariga, Katsuhiko*; Yamauchi, Yusuke*

Small, 14(21), p.1800474_1 - 1800474_14, 2018/05

no abstracts in English

Journal Articles

Molybdenum adsorption properties of alumina-embedded mesoporous silica for medical radioisotope production

Saptiama, I.*; Kaneti, Y. V.*; Oveisi, H.*; Suzuki, Yoshitaka; Tsuchiya, Kunihiko; Takai, Kimiko*; Sakae, Takeji*; Pradhan, S.*; Hossain, M. S. A.*; Fukumitsu, Nobuyoshi*; et al.

Bulletin of the Chemical Society of Japan, 91(2), p.195 - 200, 2018/02

 Times Cited Count:13 Percentile:4.41(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Preferred site occupation of 3$$d$$ atoms in Ni$$_{x}$$Fe$$_{4-x}$$N (${it x}$ = 1 and 3) films revealed by X-ray absorption spectroscopy and magnetic circular dichroism

Takata, Fumiya*; Ito, Keita*; Takeda, Yukiharu; Saito, Yuji; Takanashi, Koki*; Kimura, Akio*; Suemasu, Takashi*

Physical Review Materials (Internet), 2(2), p.024407_1 - 024407_5, 2018/02

Journal Articles

Mesoporous alumina as an effective adsorbent for molybdenum (Mo) toward Instant production of radioisotope for medical use

Saptiama, I.*; Kaneti, Y. V.*; Suzuki, Yumi*; Suzuki, Yoshitaka; Tsuchiya, Kunihiko; Sakae, Takeji*; Takai, Kimiko*; Fukumitsu, Nobuyoshi*; Alothman, Z. A.*; Hossain, M. S. A.*; et al.

Bulletin of the Chemical Society of Japan, 90(10), p.1174 - 1179, 2017/10

 Times Cited Count:23 Percentile:7.51(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Microscopic analyses of complexes formed in adsorbent for Mo and Zr separation chromatography

Abe, Ryoji*; Nagoshi, Kohei*; Arai, Tsuyoshi*; Watanabe, So; Sano, Yuichi; Matsuura, Haruaki*; Takagi, Hideaki*; Shimizu, Nobutaka*; Koka, Masashi*; Sato, Takahiro*

Nuclear Instruments and Methods in Physics Research B, 404, p.173 - 178, 2017/08

 Percentile:100(Instruments & Instrumentation)

Journal Articles

Flushing phenomena and flow structure by microwave heating

Fujita, Shunya*; Abe, Yutaka*; Kaneko, Akiko*; Chonan, Fuminori*; Yuasa, Tomohisa*; Yamaki, Tatsunori*; Segawa, Tomoomi; Yamada, Yoshikazu

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 8 Pages, 2017/07

From the observation results, in the process of flushing, the behaviors leading to flushing were classified divided into three types. First type is that first generation bubble from heating leads to flushing. Second type is that nucleate boiling continues during heating and stop, finally single bubble generates and leads to flushing. Third type is defined that gradual evaporation occurs without bubbles. It was revealed that the total quantities of heat released by flushing are approximately equal when assuming the flushing mechanism, it can be triggered that a large amount of micro bubbles are instantaneously generated and grew.

Journal Articles

Development of $$^{99}$$Mo/$$^{99m}$$Tc generator for the $$^{99}$$Mo/$$^{99m}$$Tc domestic production

Fukumitsu, Nobuyoshi*; Tsuchiya, Kunihiko; Ariga, Katsuhiko*; Yamauchi, Yusuke*

Isotope News, (742), p.20 - 24, 2016/02

no abstracts in English

Journal Articles

SENJU; A New time-of-flight single-crystal neutron diffractometer at J-PARC

Ohara, Takashi; Kiyanagi, Ryoji; Oikawa, Kenichi; Kaneko, Koji; Kawasaki, Takuro; Tamura, Itaru; Nakao, Akiko*; Hanashima, Takayasu*; Munakata, Koji*; Moyoshi, Taketo*; et al.

Journal of Applied Crystallography, 49(1), p.120 - 127, 2016/02

 Times Cited Count:13 Percentile:11.41(Chemistry, Multidisciplinary)

Journal Articles

Breakup and fragmentation behavior of molten material jet in multi-channel of BWR lower plenum

Saito, Ryusuke*; Abe, Yutaka*; Yoshida, Hiroyuki

Journal of Nuclear Science and Technology, 53(2), p.147 - 160, 2016/02

 Times Cited Count:4 Percentile:31.55(Nuclear Science & Technology)

Journal Articles

New application of NV centers in CVD diamonds as a fluorescent nuclear track detector

Onoda, Shinobu; Haruyama, Moriyoshi; Teraji, Tokuyuki*; Isoya, Junichi*; Kada, Wataru*; Hanaizumi, Osamu*; Oshima, Takeshi

Physica Status Solidi (A), 212(11), p.2641 - 2644, 2015/11

 Times Cited Count:4 Percentile:66.91(Materials Science, Multidisciplinary)

Journal Articles

Negative correlation between electrical response and domain size in a Ti-composition-gradient Pb[(Mg$$_{1/3}$$Nb$$_{2/3}$$)$$_{1-x}$$Ti$$_{x}$$]O$$_{3}$$ crystal near the morphotropic phase boundary

Shimizu, Daisuke*; Tsukada, Shinya*; Matsuura, Masato*; Sakamoto, Junya*; Kojima, Seiji*; Namikawa, Kazumichi*; Mizuki, Junichiro; Owada, Kenji

Physical Review B, 92(17), p.174121_1 - 174121_5, 2015/11

 Times Cited Count:4 Percentile:66.91(Materials Science, Multidisciplinary)

The phase diagram and the relationship between the crystal coherence length and electrical response of Pb[(Mg$$_{1/3}$$Nb$$_{2/3}$$)$$_{1-x}$$Ti$$_{x}$$]O$$_{3}$$ (PMN-xPT) near the morphotropic phase boundary (MPB) have been precisely investigated using a single crystal with a Ti composition gradient by synchrotron X-ray diffraction and inelastic light scattering at room temperature. The crystal has two boundaries at Ti compositions of 29.0 mol% and 34.7 mol% which correspond to the phase boundaries between the monoclinic B (MB) and C (MC) phases and between the MC and tetragonal (T) phases, respectively. It is shown that there is a strong negative correlation between the electrical response and the crystal coherence length at the sub-$$mu$$m scale. The results are explained by the size effects of domains near the MPB.

Journal Articles

NV centers in diamond used for detection of single ion track

Haruyama, Moriyoshi; Onoda, Shinobu; Kada, Wataru*; Teraji, Tokuyuki*; Isoya, Junichi*; Oshima, Takeshi; Hanaizumi, Osamu*

Proceedings of 11th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-11) (Internet), p.184 - 187, 2015/11

Journal Articles

The Criteria of flushing phenomena under microwave heating

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:53.75(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$$_{2}$$ 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.

Journal Articles

Hydrogen at zinc vacancy of ZnO; An EPR and ESEEM study

Son, N. T.*; Isoya, Junichi*; Ivanov, I. G.*; Oshima, Takeshi; Janz$'e$n, E.*

AIP Conference Proceedings 1583, p.341 - 344, 2014/02

329 (Records 1-20 displayed on this page)