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Ouchi, Kazuki
Hosha Kagaku, (49), p.3 - 7, 2024/03
I introduce the elucidation of the deposition following the oxidation state of uranium and the electrochemical behavior of uranium(IV) chloride in an ionic liquid-organic mixture, as a basic study of in-solution reactions. In addition, I introduce the development of separation methods for actinides using a microchemical chip and polyacrylamide gel electrophoresis, as an applied study for quantitative analytical methods for small amounts of samples.
Kubo, Shinji
Suiso Enerugi Shisutemu, 48(2), p.126 - 132, 2023/06
no abstracts in English
Nii, Keisuke*; Ida, Yoshiaki*; Ueda, Hideki*; Yamaguchi, Takanori*; Kabumoto, Hiroshi; Kamiya, Junichiro; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; et al.
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.601 - 604, 2023/01
no abstracts in English
Sakasegawa, Hideo; Nomura, Mitsuo; Sawayama, Kengo; Nakayama, Takuya; Yaita, Yumi*; Yonekawa, Hitoshi*; Kobayashi, Noboru*; Arima, Tatsumi*; Hiyama, Toshiaki*; Murata, Eiichi*
Progress in Nuclear Energy, 153, p.104396_1 - 104396_9, 2022/11
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)When dismantling centrifuges in uranium-enrichment facilities, decontamination techniques must be developed to remove uranium-contaminated surfaces of dismantled parts selectively. Dismantled uranium-contaminated parts can be disposed of as nonradioactive wastes or recycled after decontamination appropriate for clearance. previously, we developed a liquid decontamination technique using acidic electrolyzed water to remove uranium-contaminated surfaces. However, further developments are still needed for its actual application. Dismantled parts have various uranium-contaminated surface features due to varied operational conditions, inhomogeneous decontamination using iodine heptafluoride gas, and changes in long-term storage conditions after dismantling. Here, we performed liquid decontamination on specimens with varying uranium-contaminated surfaces cut from a centrifuge made of low-carbon steel. From the results, the liquid decontamination can effectively remove the uranium-contaminated surfaces, and radioactive concentrations fell below the target value within twenty minutes. Although the required time should also depend on dismantled parts' sizes and shapes in their actual application, we demonstrated that it could be an effective decontamination technique for uranium-contaminated steels of dismantled centrifuges.
Nakano, Hiroko; Fuyushima, Takumi; Tsuguchi, Akira*; Nakamura, Mutsumi*; Takeuchi, Tomoaki; Takemoto, Noriyuki; Ide, Hiroshi
JAEA-Technology 2022-007, 34 Pages, 2022/06
JAEA-Technology-2022-007.pdf:3.35MB
In order to investigate the phenomenon of stress corrosion cracking (SCC) for structural materials at the light water reactor (LWR), it is important to manage a water quality for simulating high-temperature and high-pressure water. Generally, dissolved hydrogen (DH) concentration in water loop has been controlled by the bubbling method of pure hydrogen gas or standard gas with high hydrogen concentration. However, it is necessary to equip the preventing hydrogen explosion in the area installed experimental apparatus. In general, in order to prevent accident by hydrogen, it is required to take measures such as limiting the amount of leakage, eliminating hydrogen, shutting off the power supply, and suppressing combustion before an explosion occurs. Thus, the dissolved hydrogen concentration control apparatus by electrolysis method has been developed which has two electrolysis cells to control DH concentration by electrolyzing water loop. In this study, small basic experimental devices were set up. The preliminary data were acquired regarding the simple performance of two electrolysis cells and the change of DH concentration in circulation. Based on the preliminary data, the dissolved hydrogen concentration control apparatus was designed to be connected to the high-temperature and high-pressure water loop test equipment. This report describes the test results with the small basic experimental devices for the design of the dissolved hydrogen concentration control apparatus.
Nii, Keisuke*; Ida, Yoshiaki*; Ueda, Hideki*; Yamaguchi, Takanori*; Kabumoto, Hiroshi; Kamiya, Junichiro; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; et al.
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.334 - 337, 2021/10
no abstracts in English
Li
TiO
(x = 0.13) studied by quasielastic neutron scatteringMatsuura, Masato*; Fujiwara, Yasuyuki*; Moriwake, Hiroki*; Ohara, Koji*; Kawakita, Yukinobu
Physical Review B, 104(9), p.094305_1 - 094305_7, 2021/09
Times Cited Count：5 Percentile：44.86(Materials Science, Multidisciplinary)
GeP
S
Yajima, Takeshi*; Hinuma, Yoyo*; Hori, Satoshi*; Iwasaki, Rui*; Kanno, Ryoji*; Ohara, Takashi; Nakao, Akiko*; Munakata, Koji*; Hiroi, Zenji*
Journal of Materials Chemistry A, 9(18), p.11278 - 11284, 2021/05
Times Cited Count：19 Percentile：80.41(Chemistry, Physical)Tateno, Haruka; Sato, Takumi; Tsubata, Yasuhiro; Hayashi, Hirokazu
Journal of Nuclear Science and Technology, 57(3), p.224 - 235, 2020/03
Times Cited Count：6 Percentile：55.67(Nuclear Science & Technology)Fuel cycle technology for the transmutation of long-lived minor actinides (MAs) using an accelerator-driven system has been developed using the double-strata fuel cycle concept. A mononitride solid solution of MAs and Pu diluted with ZrN is a prime fuel candidate for the accelerator-driven transmutation of MAs. Pyro-reprocessing is suitable for recycling the residual MAs in irradiated nitride fuel with high radiation doses and decay heat. Spent nitride fuel is anodically dissolved, and the actinides are recovered simultaneously into a liquid cadmium cathode via molten salt electrorefining. The process should be designed to achieve the target recovery yield of MAs and the acceptable impurity level of rare earths in the recovered material. We evaluated the material balance during the pyro-reprocessing of spent nitride fuel to gain important insight on the design process. We examined the effects of changing processing conditions on material flow and quantity of waste.
Nakayama, Takuya; Nomura, Mitsuo; Mita, Yutaka; Yonekawa, Hitoshi*; Bunbai, Misako*; Yaita, Yumi*; Murata, Eiichi*; Hosaka, Katsumi*; Sugitsue, Noritake
Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 8 Pages, 2019/05
Clearance of contaminated metal is important for recycling and volume reduction of radioactive waste. Among applicable decontamination technologies, immersion method with ultrasonic cleaning is considered to be effective for metal materials having various shapes. in this study is to demonstrate decontamination of carbon steel contaminated by uranium hexafluoride to the target level for clearance (less than 0.04 Bq/cm
), and minimize secondary waste. In this test, acidic electrolytic water, dilute hydrochloric acid, dilute sulfuric acid and ozone water with various pH and redox potential were used as decontamination solutions to be tested. We found that acidic electrolytic water is effective solution for decontamination of carbon steel contaminated by uranium hexafluoride. It could be decontaminate less than target level for clearance, and reduced secondary waste relatively.
Kitatsuji, Yoshihiro
Radioisotopes, 67(10), p.483 - 493, 2018/10
Electrochemical reactions and redox properties of actinides such as uranium and neptunium are outlined. The flow electrolysis enables rapid and high-efficient treatment. It was demonstrated to measure slow processes of actinide redox. Experimental results of electrolysis of actinide ions and the preparation method of oxidation state of the ions based on the fundamental data are described. Mediator reaction and catalysis observed in the process of electrolysis of actinide ions are also explained.
Kubo, Shinji; Iwatsuki, Jin; Takegami, Hiroaki; Kasahara, Seiji; Tanaka, Nobuyuki; Noguchi, Hiroki; Kamiji, Yu; Onuki, Kaoru
JAEA-Technology 2015-028, 32 Pages, 2015/10
JAEA-Technology-2015-028.pdf:23.69MB
JAEA has been conducting a study on IS process for thermochemical hydrogen production in order to develop massive hydrogen production technology for hydrogen society. Integrity of the chemical reactors and concentration technology of hydrogen iodide in HIx solution were studied. In the former study, the chemical reactors were trial-fabricated using industrial materials. A test of 30 times of thermal cycle test under circulating condition of the Bunsen reaction solution showed integrity of the Bunsen reactor made of fluororesin lined steel. Also, 100 hours of reaction tests showed integrity of the sulfuric acid decomposer made of silicon carbide and of the hydrogen iodide decomposer made of Hastelloy C-276. In the latter study, concerning electro-electrodialysis using cation-exchange membrane, sulfuric acid in the anolyte had little influence on the concentration performance. These results suggest the purification system of HIx solution can be simplified. Based on the Nernst-Planck equation and the Smoluchowski equation, proton transport number, water permeance, and IR drop of the cation exchange membrane were formulated. The derived equations enable quantitative estimation for the performance indexes of Nafion membrane and, also, of ETFE-St membranes made by radiation-induced graft polymerization method.
emission reduction of active carbon recycling energy system for ironmaking by modeling with Aspen PlusSuzuki, Katsuki*; Hayashi, Kentaro*; Kurihara, Kohei*; Nakagaki, Takao*; Kasahara, Seiji
ISIJ International, 55(2), p.340 - 347, 2015/02
Times Cited Count：19 Percentile：64.17(Metallurgy & Metallurgical Engineering)Use of the Active Carbon Recycling Energy System in ironmaking (iACRES) has been proposed for reducing CO emissions. To evaluate the performance of iACRES quantitatively, a process flow diagram of a blast furnace model with iACRES was developed using Aspen Plus, a chemical process simulator. CO emission reduction and exergy analysis were performed by using mass and energy balance obtained from simulation results. The following CO reduction methods were evaluated as iACRES: solid oxide electrolysis cells (SOEC) with CO capture and separation (CCS), SOEC without CCS, and a reverse water-gas shift reactor powered by a high-temperature gas-cooled reactor. iACRES enabled CO emission reduction by 3-11% by recycling CO and H, whereas effective exergy ratio decreased by 1-7%.
Hayashi, Kentaro*; Suzuki, Katsuki*; Kurihara, Kohei*; Nakagaki, Takao*; Kasahara, Seiji
Tanso Junkan Seitetsu Kenkyukai Saika Hokokusho; Tanso Junkan Seitetsu No Tenkai, p.27 - 41, 2015/02
Applying Active Carbon Recycling Energy System to ironmaking (iACRES) process is a promising technology to reduce coal usage and CO emissions. To evaluate performance of iACRES quantitatively, a process flow diagram of the blast furnace model with iACRES was developed using Aspen Plus. CO emission reduction and exergy analysis was predicted by using mass and energy balance obtained from the simulation results. The followings were investigated as iACRES: solid oxide electrolysis cells (SOEC) with CO capture and separation (CCS), SOEC without CCS, and a reverse water-gas shift reactor as the a CO reduction reactor powered by a high-temperature gas-cooled reactor. iACRES could provide CO emission reductions of 3-11% by recycling CO and H, whereas the effective exergy ratio decreased by 1-7%.
Tran Duy, T.*; Sawada, Shinichi; Hasegawa, Shin; Yoshimura, Kimio; Oba, Yojiro*; Onuma, Masato*; Katsumura, Yosuke*; Maekawa, Yasunari
Macromolecules, 47(7), p.2373 - 2383, 2014/04
Times Cited Count：30 Percentile：70.08(Polymer Science)The hierarchical structures of graft-type ETFE-based polymer electrolyte membranes (ETFE-PEMs) were investigated using small- and ultrasmall-angle X-ray cattering experiments. The ETFE-PEMs with IECs 
2.4 mmol/g possessed conducting graft domains around lamellar crystals, with a d-spacing of 21.8-29.1 nm, and oriented crystallites with short and long correlation distances of 218-320 and 903-1124 nm, respectively. The membranes with IECs 
2.7 mmol/g showed a new phase of crystallite network domains with a d-range of 225-256 nm, indicating a phase transition from oriented crystallite to crystallite network structures in the IEC range of 2.4-2.7 mmol/g. Noted that for the ETFE-PEMs with high IECs higher conductivity at 30% RH and compatible tensile strengths at 100% RH and 80 
C, compared with Nafion, originated from the well-interconnected ion channels around the crystallites and the remaining lamellar crystals and crystallites, respectively.
Iwai, Yasunori; Yamanishi, Toshihiko; Isobe, Kanetsugu; Nishi, Masataka; Yagi, Toshiaki; Tamada, Masao
Fusion Engineering and Design, 81(1-7), p.815 - 820, 2006/02
Times Cited Count：15 Percentile：70.56(Nuclear Science & Technology)Solid-polymer-electrolyte (SPE) water electrolysis is attractive in electrolytic process of water detritiation system (WDS) in fusion reactors because it can electrolyze liquid waste directly, but radioactive durability of its ion exchange membrane is a key point. Radioactive durability of Nafion, a typical commercial ion exchange membrane, was experimentally investigated using Co-60 irradiation facility and electron beam irradiation facility at Takasaki Radiation Chemistry Research Establishment of JAERI. Nafion is composed of PTFE (Polytetrafluoroethylene) main chain. However the degradation of its mechanical strength by irradiation was significantly distinguished from that of PTFE and no serious damage was observed for its ion exchange capacity up to 530 kGy, the requirement of ITER. Atmospheric effects such as soaking and oxygen on degrading behaviors were discussed from the viewpoint of radical reaction mechanism. Dependencies of operating temperature and radioactive source are also demonstrated in detail.
Yamanishi, Toshihiko; Iwai, Yasunori; Kawamura, Yoshinori; Nishi, Masataka
Fusion Engineering and Design, 81(1-7), p.797 - 802, 2006/02
Times Cited Count：9 Percentile：53.38(Nuclear Science & Technology)no abstracts in English
Iwai, Yasunori; Yamanishi, Toshihiko; Nishi, Masataka; Yagi, Toshiaki; Tamada, Masao
Journal of Nuclear Science and Technology, 42(7), p.636 - 642, 2005/07
Times Cited Count：20 Percentile：77.57(Nuclear Science & Technology)Radioactive durability of organic polymers in solid-polymer-electrolyte water electrolyzer was investigated by 
-ray irradiation. Serious deteriorations for tensile strength and ion exchange capacity of ion exchange membrane (Nafion) were not observed up to 850 kGy. No serious damage was also observed for the gasket materials (Aflas) up to 500 kGy. PFA and FEP, insulator materials, lost their tensile strength at 300 kGy or less. As the result, it is concluded that the electrolyzer could be used up to around 500 kGy in the case where PFA and FEP are replaced by the polyimide resin whose durability is well demonstrated. Two degrading mechanisms were supposed. One is direct degradation by energy of radial rays. The other is that by the attack of radicals. It was demonstrated that the effect of radicals on the membrane was not dominant. The quantity of dissolved fluorine in water was found to correlate with the tensile strength and ion exchange capacity. Hence, it is possible to evaluate the degradation of the membrane by monitoring the quantity of dissolved fluorine.
Yamaki, Tetsuya; Asano, Masaharu; Yoshida, Masaru
Gekkan Eko Indasutori, 10(6), p.5 - 11, 2005/06
no abstracts in English
Yamaki, Tetsuya; Asano, Masaharu; Yoshida, Masaru
Kogyo Zairyo, 53(1), p.63 - 67, 2005/01
no abstracts in English
