荒井 陽一; 渡部 創; 大野 真平; 野村 和則; 中村 文也*; 新井 剛*; 瀬古 典明*; 保科 宏行*; 羽倉 尚人*; 久保田 俊夫*
Nuclear Instruments and Methods in Physics Research B, 477, p.54 - 59, 2020/08
Used PUREX process solvent generated from reprocessing process of spent nuclear fuel contains a small amount of U and Pu complexed with tributyl phosphate (TBP) or dibutyl phosphate (DBP). The radioactive nuclides should be removed from the solvent for safety storage or disposal. The iminodiacetic acid (IDA) type chelating resin was proposed as promising procedures for efficient recovery of the trapped cations in the solvent. In order to reveal the distribution and amount of Zr in the particle and local structure of Zr complex formed in the adsorbent, PIXE and EXAFS analyses on the Zr adsorbed chelating resin were carried out. Micro-PIXE analysis proved that it is an effectual method for quantitative analysis of trace adsorbed elements. Moreover, some of the adsorption sites were possibly occupied by the molecules. On the other hand, Zr-K edge EXAFS analysis suggested that extraction mechanism of Zr from the aqueous solution and the solvent was different.
山内 宏樹; Sari, D. P.*; 渡邊 功雄*; 安井 幸夫*; Chang, L.-J.*; 近藤 啓悦; 伊藤 孝; 石角 元志*; 萩原 雅人*; Frontzek, M. D.*; et al.
Communications Materials (Internet), 1, p.43_1 - 43_6, 2020/07
JAEA-Review 2019-028, 71 Pages, 2020/03
荒井 陽一; 渡部 創; 大野 真平; 野村 和則; 中村 文也*; 新井 剛*; 瀬古 典明*; 保科 宏行*; 久保田 俊夫*
QST-M-23; QST Takasaki Annual Report 2018, P. 59, 2020/03
Radioactive spent solvent waste contains U and Pu is generated from reprocessing process of spent nuclear fuel. The nuclear materials should be removed from the solvent for safety storage or disposal. We are focusing on the nuclear materials recovery from spent solvent using imino diacetic acid (IDA) type chelating resin as a promising method. In order to reveal adsorbed amount of Zr, which is simulated of Pu, Micro-Particle Induced X-ray Emission (PIXE) was carried out. Micro-PIXE analysis succeeded in quantitative analysis on trace amount of adsorbed Zr from simulated spent solvent.
渡部 創; 先崎 達也; 柴田 淳広; 野村 和則; 竹内 正行; 中谷 清治*; 松浦 治明*; 堀内 勇輔*; 新井 剛*
Journal of Radioanalytical and Nuclear Chemistry, 322(3), p.1273 - 1277, 2019/12
Extraction chromatography flow-sheet employing octyl(phenyl)--diisobutylcarbonoylmethylphosphine oxide (CMPO) and (2-ethylhexyl) hydrogen phosphate (HDEHP) extractants for trivalent minor actinide recovery was modified to improve column separation performance. Excellent trivalent minor actinides recovery performance was obtained by column separation experiments on nitric acid solution containing the trivalent minor actinides and representative fission product elements, i.e. recovery yields 93% with sufficient decontamination factors against the fission products. Those are the best performance which we have ever obtained by experiments inside hot cell.
Myagmarjav, O.; 田中 伸幸; 野村 幹弘*; 久保 真治
International Journal of Hydrogen Energy, 44(59), p.30832 - 30839, 2019/11
In this study, the catalytic decomposition of hydrogen iodide was theoretically and experimentally investigated in a silica-based ceramic membrane reactor to assess the reactors suitability for thermochemical hydrogen production. The silica membranes were fabricated by depositing a thin silica layer onto the surface of porous alumina ceramic support tubes via counter-diffusion chemical vapor deposition of hexyltrimethoxysilane. The performance of the silica-based ceramic membrane reactor was evaluated by exploring important operating parameters such as the flow rates of the hydrogen iodide feed and the nitrogen sweep gas. The influence of the flow rates on the hydrogen iodide decomposition conversion was investigated in the lower range of the investigated feed flow rates and in the higher range of the sweep-gas flow rates. The experimental data agreed with the simulation results reasonably well, and both highlighted the possibility of achieving a conversion greater than 0.70 at decomposition temperature of 400C. Therefore, the developed silica-based ceramic membrane reactor could enhance the total thermal efficiency of the thermochemical process.
渡部 創; 小木 浩通*; 荒井 陽一; 粟飯原 はるか; 高畠 容子; 柴田 淳広; 野村 和則; 神谷 裕一*; 浅沼 徳子*; 松浦 治明*; et al.
Progress in Nuclear Energy, 117, p.103090_1 - 103090_8, 2019/11
A new collaborative research project for systematic treatments of radioactive liquid wastes containing various reagents generating in nuclear facilities was started from 2018 initiated by Japan Atomic Energy Agency. The project was named as STRAD (Systematic Treatments of RAdioactive liquid wastes for Decommissioning) project. Tentative targets to be studied under the project are aqueous and organic liquid wastes which have been generated by experiments and analyses in a reprocessing experimental laboratory of JAEA. Currently fundamental studies for treatments of the liquid wastes with complicated compositions are underway. In the STRAD project, process flow for treatment of ammonium ion involved in aqueous waste was designed though the inactive experiments, and decomposition of ammonium ion using catalysis will be carried out soon. Adsorbents for recovery of U and Pu from spent solvent were also developed. Demonstration experiments on genuine spent solvent is under planning.
大高 稔紀*; 佐藤 辰巳*; 大野 真平; 名越 航平; 安倍 諒治*; 新井 剛*; 渡部 創; 佐野 雄一; 竹内 正行; 中谷 清治*
Analytical Sciences, 35(10), p.1129 - 1133, 2019/10
Single porous silica microparticles coated with styrene-divinylbenzene polymer (SDB) impregnated with octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) were injected into an aqueous 3 mol/L nitric acid solution containing trivalent lanthanide (Ln(III)), as a high-level liquid waste model, using the microcapillary manipulation-injection technique; and the extraction rate of Ln(III), as an Ln(III)-CMPO complex, into the single microparticles was measured by luminescence microspectroscopy. The extraction rate significantly depended on the Ln(III), CMPO, or NO concentration, and was analyzed in terms of diffusion in the pores of the microparticles and complex formation of Ln(III). The results indicated that the rate-determining step in Ln(III) extraction was the diffusion in the pore solution of the microparticles.
渡部 創; 片井 雄也*; 松浦 治明*; 加田 渉*; 江夏 昌志*; 佐藤 隆博*; 新井 剛*
Nuclear Instruments and Methods in Physics Research B, 450, p.61 - 65, 2019/07
Ion-beam induced luminescence (IBIL) analysis on MA recovery adsorbent was performed to give chemical states of complexes formed in the adsorbent as fundamental information for process design, and EXAFS analysis was also carried out to support discussions. The IBIL spectra of the binary extractants system seemed to be superposition of individual ones, however it has also original peaks. As intensities of those peaks rapidly decreased with iteration time of measurements and the original peaks were not observed for the adsorbent without charging Eu(III), they were attributed to complexes of Eu(III) with organic compounds. Contributions of CMPO and HDEHP extractants for Eu(III) extraction must be not only individual ones but also cooperative.
Myagmarjav, O.; 田中 伸幸; 野村 幹弘*; 久保 真治
International Journal of Hydrogen Energy, 44(21), p.10207 - 10217, 2019/04
The potential of the silica membrane reactors for use in the decomposition of hydrogen iodide (HI) was investigated by simulation with the aim of producing CO-free hydrogen via the thermochemical water-splitting iodine-sulfur process. Simulation model validation was done using the data derived from an experimental membrane reactor. The simulated results showed good agreement with the experimental findings. The important process parameters determining the performance of the membrane reactor used for HI decomposition, namely, reaction temperature, total pressures on both the feed side and the permeate side, and HI feed flow rate were investigated theoretically by means of a simulation. It was found that the conversion of HI decomposition can be improved by up to four times (80%) or greater than the equilibrium conversion (20%) at 400C by employing a membrane reactor equipped with a tubular silica membrane. The features to design the membrane reactor module for HI decomposition of thermochemical iodine-sulfur process were discussed under a wide range of operation conditions by evaluating the relationship between HI conversion and number of membrane tubes.
渡部 創; 佐野 雄一; 三田 修平*; 桜井 翔太*; 新井 剛*
日本イオン交換学会誌, 30(1), p.8 - 16, 2019/01
In order to optimize operability of the adsorbents in the extraction chromatography system and to enhance the performance of the adsorbent, CMPO/SiO-P adsorbents with various pore and particle sizes were prepared, and characteristics of the adsorbents were evaluated through distribution coefficient, adsorption isotherm, adsorption rate, and breakthrough/elution behavior. Adsorption capacity was dominated not by the structure of the adsorbent but by amount of the extractant impregnated. The adsorbent with the largest pore size were revealed to show quick elution with short tail. Enlargement in the pore size must be one of the most effective improvements of the adsorbents to enhance the adsorption/elution performance. Adsorbent with particle size of more than 200 m formed channeling or voids inside the bed. They are suspected to lead slow adsorption/elution behavior, and smaller adsorbents must be desirable in the respect of performance of the column.
Myagmarjav, O.; 田中 伸幸; 野村 幹弘*; 久保 真治
International Journal of Hydrogen Energy, 42(49), p.29091 - 29100, 2017/12
佐野 雄一; 渡部 創; 松浦 治明*; 名越 航平*; 新井 剛*
Journal of Nuclear Science and Technology, 54(10), p.1058 - 1064, 2017/10
渡部 創; 佐野 雄一; 塩飽 秀啓; 矢板 毅; 大野 真平*; 新井 剛*; 松浦 治明*; 江夏 昌志*; 佐藤 隆博*
Nuclear Instruments and Methods in Physics Research B, 404, p.202 - 206, 2017/08
Extraction chromatography is one of the most promising technology for minor actinide (MA(III): Am and Cm) recovery from high level liquid waste generated in the reprocessing. A brand-new adsorbent proposed by our group are expected to achieve more efficient MA(III) recovery than usual procedure. Fundamental MA(III) adsorption/elution performances of the adsorbents have been demonstrated. An appropriate washing process of lanthanides (Ln(III)) is necessary to be established to design a process flow. In this study, chemical state and distribution of Eu inside the adsorbent before and after contacting with candidate eluents for MA(III) or Ln(III) were evaluated by EXAFS measurements and micro-PIXE analysis, respectively. Two-dimensional PIXE images showed that adsorbed Eu and residual Eu after contacting with the eluents for MA(III) were uniformly distributed on the particle. However, EXAFS oscillation revealed that local structure around Eu drastically changes by the contact. Those results suggest that the Eu remained inside the particle without distinct shift and that they form various complexes with extractants in the particle.
安倍 諒治*; 名越 航平*; 新井 剛*; 渡部 創; 佐野 雄一; 松浦 治明*; 高木 秀彰*; 清水 伸隆*; 江夏 昌志*; 佐藤 隆博*
Nuclear Instruments and Methods in Physics Research B, 404, p.173 - 178, 2017/08
Molybdenum and zirconium obstruct the efficient recovery of minor actinides (MA(III): Am(III) and Cm(III)) by extraction chromatography; hence, the removal of these elements prior to MA(III) recovery is desirable. The use of an adsorbent impregnated with bis(2-ethylhexyl) hydrogen phosphate (HDEHP) for Mo and Zr decontamination was evaluated in this report. The adsorption/elution and column separation experiments showed that Mo and Zr in the simulated HLLW were selectively adsorbed on the particles, and that Mo was eluted by HO. EXAFS analysis and SAXS patterns of the adsorbent containing Zr revealed that the Zr-HDEHP complex had a crystal-like periodic structure similar to the structure of the precipitate produced in the solvent extraction system. Micro-PIXE analysis revealed that distribution of the residual Zr on the adsorbent was uniform.
名越 航平*; 新井 剛*; 渡部 創; 佐野 雄一; 竹内 正行; 佐藤 睦*; 及川 博史*
日本イオン交換学会誌, 28(1), p.11 - 18, 2017/01
田邊 祐介*; 岩本 隆志*; 高橋 潤一*; 西川 宏之*; 佐藤 隆博; 石井 保行; 神谷 富裕
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 129, 2013/01
In this study, the Ni microstructures were attempted to be fabricated on a distal surface of Cu wires with a diameter of 1.0 mm aiming at the use for imprint lithography. Firstly a PMMA master block was fabricated on the distal surface by exposing PB with beam size of 1.1 m at 3.0 MeV and developing it by IPA-water for electroplating. The master block was composed of the 4-m wide lines with pitches of 25 m and depths of 20 m. Secondly the electroplating was performed on the PMMA master block using a nickel sulfamate bath. Thirdly the electroplated Ni surface was mechanically polished easily to remove PMMA by smoothing its surface. Finally, the Ni microstructures with 20.5 m were fabricated by removing the PMMA after polishing. We additionally performed UV imprint lithography of the photosensitive polymer using the Ni microstructures as a mold. The observation result of SEM images of Ni microstructures and UV imprinted grooves showed that their imprinted grooves were successfully transferred by way of the Ni microstructures from the PMMA master block using the combination of the electroplating and imprinting.
大道 正明*; 高野 勝昌*; 佐藤 隆博; 神谷 富裕; 石井 保行; 大久保 猛; 江夏 昌志; 加田 渉; 杉本 雅樹; 西川 宏之*; et al.
Journal of Nanoscience and Nanotechnology, 12, p.7401 - 7404, 2012/09
A new visualization method for dose distribution of a focused proton beam in sub-micrometer scale was developed using a formation of a bulky cross-linked structure of polyacrylic acid -, '-methylence bisacrylamide, blend film. The areas irradiated by the focused proton beam were swelled on the film. The height of the swelling was significantly increased according to the beam fluence and the increase of containing ratio of the methylence bisacrylamide. The height was saturated at the fluence of 510 ions/m. The proton beam-sensitive polymer film was used for the analysis of dose distribution on its surface. The irradiated surface was observed by employing an atomic force microscope. This observation result showed that the method could be used to confirm the writing patterns and the beam-spot shape. Nanostructures with a crescent shape are visualized clearly at a misaligned beam-spot shape in the set up of the beam-optics.
高野 勝昌*; 佐藤 隆博; 神谷 富裕; 石井 保行; 大久保 猛; 江夏 昌志; 加田 渉; 杉本 雅樹; 関 修平*; 西川 宏之*
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 162, 2012/01
A unique micro-processing technique for epoxy resin films has been developed at the TIARA, utilizing the ion beam writing with multiple energies of light and heavy ion beams. In this study, nano-wire structure fabrication was tried by a superimposing with the proton beams and 520 MeV Ar. And in order to reduce the surface tension in developing and drying processes, after a baking at 95 C for 1 minute, developing and drying was performed with super-critical CO at 12 MPa, 40 C. As the result, the bridge structure which strung the wires fabricated by 520 MeV Ar hitting can be observed at the aimed points.
田邊 祐介*; 西川 宏之*; 佐藤 隆博; 石井 保行; 神谷 富裕
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 163, 2012/01
We report on Ni electroforming using high-aspect-ratio PMMA microstructures by Proton Beam Writing (PBW). There are several issues to be addressed in the fabrication process of Ni molds with a high-aspect-ratio using the PMMA microstructures. First, the residual PMMA was observed on the sidewall of PMMA master block by increasing the thickness of its master block. Second, the small voids were formed in the Ni molds when the high-aspect ratio PMMA master blocks were used. These problems ware resolved using the PMMA master blocks fabricated by PBW on the condition of the higher dose exposure than ordinal one and using a seed layer of a 600-m thick Cu substrate evaporated on the Si substrate before spin-coating the PMMA film. The 30-m PMMA master block with the aspect ratio of 30 was successfully fabricated using the above procedures. Using this PMMA master block, the Ni mold with 30-m thick on the Cu substrate was successfully electroformed without voids from the observation of the cross section revealed by a FIB. Furthermore, a Ni mold with grids and circle patterns was also successfully fabricated using a 15-m thick PMMA film spin-coated on a Cu substrate. The result of the thermal imprint using the Ni mold demonstrated that the high aspect structure was transferred on a PMMA film without damages of the Ni mold even after many trials.