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.
渡部 創; 佐野 雄一; 岡田 諒*; 松浦 治明*; 羽倉 尚人*; 加田 渉*
Nuclear Instruments and Methods in Physics Research B, 477, p.60 - 65, 2020/08
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.
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.
渡部 創; 小木 浩通*; 柴田 淳広; 野村 和則
International Journal of Nuclear and Quantum Engineering (Internet), 13(4), p.169 - 174, 2019/04
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.
野村 和則; 小木 浩通*; 中原 将海; 渡部 創; 柴田 淳広
International Journal of Nuclear and Quantum Engineering (Internet), 13(5), p.209 - 212, 2019/00
Chemical Processing Facility of Japan Atomic Energy Agency is a basic research field for advanced back-end technology developments with using actual high-level radioactive materials. Most of them were treated properly and stored in the liquid waste vessel, but some were not treated and remained at the experimental space as a kind of legacy nuclear waste, which we must treat in safety and dispose if we continue research activities in the facility. Under this circumstance, we launched a collaborative research project called the STRAD project, which stands for Systematic Treatment of Radioactive liquid waste for Decommissioning, in order to develop the treatment processes for wastes of the nuclear research facility. In this project, decomposition methods of certain chemicals, which have been directly solidified without safety pretreatment but may cause a troublesome phenomenon, is developing and a prospect that it will be able to decompose in the facility by simple method. And solidification of aqueous or organic liquid wastes after the decomposition has been studied by adding cement or coagulants. Furthermore, we treated experimental tools of various materials with making an effort to stabilize and to compact them before the package into the waste container. It is expected to decrease the number of transportation of the solid waste and widen the operation space. The project is expected to contribute beneficial waste management outcome that can be shared world widely.
小藤 博英; 渡部 創; 竹内 正行; 鈴木 英哉; 松村 達郎; 塩飽 秀啓; 矢板 毅
Progress in Nuclear Science and Technology (Internet), 5, p.61 - 65, 2018/11
Applicability of newly developed MA(III)/RE(III) separation extractant TPDN for the extractionchromatography technology was evaluated through series of fundamental characterizations. The adsorbentselectively extract Am from diluted high level liquid waste and sufficient performance for MA(III)/RE(III)separation process was confirmed. Durability and behavior in the vitrification process of the adsorbent alsosuggested that the new adsorbent can be employed as a material for reprocessing of spent fuels.
渡部 創; 鈴木 英哉; 後藤 一郎*; 小藤 博英; 松村 達郎
日本イオン交換学会誌, 29(3), p.71 - 75, 2018/09
Chemical compounds containing scandium (Sc) are widely applied to various fields such as catalysts, alloys, lamps and etc. Sc is found in mineral ore, and it is necessary to develop efficient Sc separation and recovery technology for the industrial applications. So far, solvent extraction based processes were proposed as promising Sc recovery procedures. Our group has found that hexaoctyl nitrilotriacetic acid triamide (HONTA) has strong affinity to Sc. In this study, applicability of the extraction chromatography technology for the selective Sc recovery was experimentally evaluated through batch-wise adsorption/elution studies and column separation experiments.
渡部 創; 佐野 雄一; 小藤 博英; 竹内 正行; 柴田 淳広; 野村 和則
Journal of Radioanalytical and Nuclear Chemistry, 316(3), p.1113 - 1117, 2018/06
Am(III) and Cm(III) recovery experiments with the extraction chromatography technology were carried out on genuine HLLW obtained by reprocessing of the Fast Reactor fuel. Modification of the flow-sheet with 2 steps column operations using CMPO/SiO-P and HDEHP/SiO-P adsorbents achieved more than 90% recovery yields for Am(III) and Cm(III) with decontamination factor of 1000 for Eu(III). This is a significant progress in development of the technology for the implementation.
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
高畠 容子; 渡部 創; 小藤 博英; 竹内 正行; 野村 和則; 佐藤 隆博*
International Journal of PIXE, 26(3&4), p.73 - 83, 2017/09
佐野 雄一; 渡部 創; 中原 将海; 粟飯原 はるか; 竹内 正行
Proceedings of International Nuclear Fuel Cycle Conference (GLOBAL 2017) (USB Flash Drive), 4 Pages, 2017/09
多田 康平; 北脇 慎一; 渡部 創; 粟飯原 はるか; 柴田 淳広; 野村 和則
Proceedings of International Nuclear Fuel Cycle Conference (GLOBAL 2017) (USB Flash Drive), 3 Pages, 2017/09
塩化物イオン(Cl)を含む放射性廃液は、乾式再処理のプロセス制御における化学分析によって生成される。この廃液を海洋に排出するためには、Clを分離してU, Puを回収する必要がある。本研究では、AgCl沈殿法と抽出クロマトグラフィー法を組み合わせてClを分離し、U, Puを回収した。沈殿試験の結果、UおよびPuが試験後に共沈しないことが分かった。固相抽出試験の結果、95%のPuが液体廃棄物から回収されたことがわかった。Uの濃度が十分でないため、Uについての放射能を分析することは困難であった。これらの結果は、これらのプロセスが廃液を海に排出する可能性を有することを示した。
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.
渡部 創; 後藤 一郎; 佐野 雄一; 野村 和則; 駒 義和
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 7 Pages, 2017/04
Clogging of the extraction chromatography column caused by inflow of insoluble residue into the bed possible to lead accumulation of decay heat and explosive gas inside the bed. Behavior of small particle is necessary to be investigated to prevent hazardous events. In this study, influence of fine particles contained in the feed solution on the clogging and on separation performance of the bed were evaluated by laboratory scale experiments. Discharging operation of the simulated particles from the bed was experimentally demonstrated using an engineering scale system. The particles were accumulated on top of the bed and hardly come inside the bed. Backwashing operation was effective to discharge a part of the accumulated powder. Supplying water into the column with normal flow rate condition was possible after the short time backwashing operation. Backwashing with cold water as a normal operation must be one of the most appropriate countermeasures for preventing from the clogging.