Ban, Yasutoshi; Suzuki, Hideya*; Hotoku, Shinobu; Tsutsui, Nao; Tsubata, Yasuhiro; Matsumura, Tatsuro
Solvent Extraction and Ion Exchange, 37(7), p.489 - 499, 2019/11
A continuous counter-current experiment to separate minor actinides (MAs: Am and Cm) was performed with -hexaochyl nitrilotriacetamide (HONTA) as an extractant. Nitric acid of 0.08 M (mol/dm) containing MAs and rare earths (REs) recovered from high-level waste was used as the Feed, and the experiment was conducted for 14 h. The ratios of Am and Cm recovered into the MA fraction measured 94.9% and 78.9%, respectively. HONTA hardly extracted Y, La, and Eu in the Feed (99.9% for Y, 99.9% for La, and 96.7% for Eu), most of which were distributed to the RE fraction. A portion of Nd was extracted by HONTA, and consequently the ratio of Nd in the RE fraction was 83.5%. The concentrations of MAs and some REs in each stage were calculated using a simulation code, and the results are consistent with the experimental values. This code indicates that the ratios of MAs in the MA fraction and REs in the RE fraction could be 99% by optimizing separation conditions.
Ban, Yasutoshi; Suzuki, Hideya; Hotoku, Shinobu; Kawasaki, Tomohiro*; Sagawa, Hiroshi*; Tsutsui, Nao; Matsumura, Tatsuro
Solvent Extraction and Ion Exchange, 37(1), p.27 - 37, 2019/00
A continuous counter-current experiment using TDdDGA was performed using mixer-settler extractors installed in a hot cell. Nitric acid containing minor actinides (MAs: Am and Cm), rare earths (REs: Y, La, Nd, and Eu), and other fission products (Sr, Cs, Zr, Mo, Ru, Rh, and Pd) was fed to the extractor. TDdDGA effectively extracted MAs and REs from the feed, while other fission products were barely extracted. The extracted MAs and REs were back-extracted by bringing them in contact with 0.02 mol/dm nitric acid, and they were collected as the MA-RE fraction. The proportions of MA and RE in the MA-RE fraction were 98% and 86%, respectively. These results demonstrated the applicability of TDdDGA as an extractant for MAs and REs.
Kaneko, Masashi; Suzuki, Hideya; Matsumura, Tatsuro
Inorganic Chemistry, 57(23), p.14513 - 14523, 2018/12
We elucidated the separation mechanism between Am(III) and Cm(III) ions by using two different types of diamide ligands, diglycolamide (DGA) and alkylated diamide amine (ADAAM), by means of the density functional theory technique and electron density analysis. The molecular geometries and formation reactions of the metal-ligand complexes were modeled by using [M(DGA)] and [M(ADAAM)(NO)(HO)]. We successfully reproduced Cm(III) selectivity over Am(III) with DGA and Am(III) selectivity over Cm(III) with ADAAM. Furthermore, we analyzed the bonding properties between the metal ion and the diamide-type ligands by using model complexes, [M(DGA)] and [M(ADAAM)(NO)(HO)], and revealed the differences in terms of the bond dissociation energy and the metal 5f-orbital participation in the covalency between the Am(III) and the Cm(III) complexes. It was suggested that the differences were key factors to understand the Am(III)/Cm(III) selectivity.
Kofuji, Hirohide; Watanabe, So; Takeuchi, Masayuki; Suzuki, Hideya; Matsumura, Tatsuro; Shiwaku, Hideaki; Yaita, Tsuyoshi
Progress in Nuclear Science and Technology (Internet), 5, p.61 - 65, 2018/11
Nagano, Tetsushi; Naganawa, Hirochika; Suzuki, Hideya; Toshimitsu, Masaaki*; Mitamura, Hisayoshi*; Yanase, Nobuyuki*; Grambow, B.
Analytical Sciences, 34(9), p.1099 - 1102, 2018/09
A previously reported emulsion flow (EF) extraction system does not include a device for refining used solvent. Therefore, the processing of large quantities of wastewater by using the EF extractor alone could lead to the accumulation of wastewater components into the solvent and diminished extraction performance. In the present study, we have developed a solvent-washing-type EF system, which is equipped with a unit for washing used solvent to prevent accumulation, and successfully applied it for treating uranium-containing wastewater.
Watanabe, So; Suzuki, Hideya; Goto, Ichiro*; Kofuji, Hirohide; Matsumura, Tatsuro
Nippon Ion Kokan Gakkai-Shi, 29(3), p.71 - 75, 2018/09
Suzuki, Hideya; Tsubata, Yasuhiro; Kurosawa, Tatsuya*; Sagawa, Hiroshi*; Matsumura, Tatsuro
Journal of Nuclear Science and Technology, 54(11), p.1163 - 1167, 2017/11
A highly practical diamide-type extractant, which is an alkyl diamide amine with 2-ethylhexyl alkyl chains (ADAAM(EH)), was investigated for mutual separation of Am(III) and Cm(III). ADAAM(EH) is a multidentate ligand with one soft N-donor atom and two hard O-donor atoms in its central frame. This tridentate arrangement of donor atoms provides selective binding to Am(III) compared to that with Cm(III) in highly acidic media, resulting in separation factors of up to 5.5. A continuous liquid-liquid extraction and stripping test was conducted using a multistage countercurrent mixer-settler extractor with ADAAM(EH) in n-dodecane. In this test, separation of Am(III) and Cm(III) was achieved with very high yield.
Kibe, Satoshi; Fujisaku, Kazuhiko*; Sakamoto, Atsushi; Sano, Yuichi; Takeuchi, Masayuki; Suzuki, Hideya; Tsubata, Yasuhiro; Matsumura, Tatsuro
JAEA-Research 2016-024, 40 Pages, 2017/02
The Japan Atomic Energy Agency has been developing some flowsheets with TDdDGA (N,N,N,Ntetradodecyldiglycolamide) extractant to recover MA (minor actinide) from raffinate. In this study, countercurrent experiments with the improved flowsheet, e.g. the addition of alcohol into the solvent for preventing the precipitation, were performed using miniature centrifugal contactors in order to compare the extraction/stripping behavior of each element with the mixer-settler type. As a result, no entrainments were observed and sufficient phase separation was achieved by centrifugal contactors without any abnormal fluid behavior, such as overflow. The extraction and stripping of Ln(III) which show the similar tendencies as MA could be achieved successfully, especially their stripping proceeded more efficiently in centrifugal contactors. This might be due to the increase in stripping rates by improving the flowsheet and to superior phase separation performance of centrifugal contactors.
Suzuki, Hideya; Tsubata, Yasuhiro; Matsumura, Tatsuro
Analytical Sciences, 33(2), p.239 - 242, 2017/02
Alkyl diamide amine (ADAAM), a new high-performance reagent with a simple structure, was examined for the mutual separation of Am(III) and Cu(III). The combination of ADAAM and Tetraethyldiglycolamide (TEDGA) as a masking agent shows selectivity for Am(III) over Cm(III) in highly acidic media with separation factors up to 41.
Suzuki, Hideya; Tsubata, Yasuhiro; Kurosawa, Tatsuya; Shibata, Mitsunobu; Kawasaki, Tomohiro; Urabe, Shunichi*; Matsumura, Tatsuro
Analytical Sciences, 32(4), p.477 - 479, 2016/04
An impeccable, high-performance new reagent called alkyl diamide amine (ADAAM) was examined from the viewpoint of mutual separation of Am(III) and Eu(III). ADAAM has three donor atoms, one soft N-donor atom and two hard O-donor atoms, in the central frame. The combination of soft and hard atoms affords a tridentate donor set of atoms that ensures remarkable extractability and selectivity of Am(III) and Eu(III) in highly acidic media.
Kibe, Satoshi; Fujisaku, Kazuhiko*; Ambai, Hiromu; Sakamoto, Atsushi; Sano, Yuichi; Takeuchi, Masayuki; Suzuki, Hideya; Tsubata, Yasuhiro; Matsumura, Tatsuro
JAEA-Research 2015-021, 40 Pages, 2016/02
The flowsheet with TDdDGA extractant has been being developed for recovering MA from PUREX raffinate. In the previous study, the yields of MA and other elements in countercurrent extraction/stripping experiments using mixer-settlers were not enough for the target and it would be due to the insufficient phase (aqueous/organic) separation. In this study, we carried out countercurrent experiments with surrogate PUREX raffinate using centrifugal contactors which had superior phase separation ability, and evaluated the extraction/stripping behavior of each element. During the operation, abnormal fluid behavior, such as overflow and entrainment, was not observed, and sufficient phase separation was achieved by centrifugal contactors. Extraction behavior of lanthanides was similar to that in mixer-settlers, but their stripping efficiencies decreased. This would be due to shorter residence time in mixing zone.
Nagano, Tetsushi; Mitamura, Hisayoshi; Yamashita, Yuji; Yanase, Nobuyuki; Suzuki, Hideya; Naganawa, Hirochika
Solvent Extraction Research and Development, Japan, 21(1), p.111 - 117, 2014/00
Simulated electroless nickel plating liquid wastes have been processed by using an emulsion flow extractor of a counter current type with a special focus on influences of dilution of the liquid wastes on the extraction performance. The emulsion flow extractor provides an efficient liquid-liquid extraction by sending solutions without additional stirring or shaking. A solvent used in the present study was Shellsol D70 solution containing LIX84-I as an extractant for nickel and PC88A as an accelerating agent. As a result, it was found that increasing degree of dilution with water resulted in improvement of nickel extractabilities obtained from the emulsion flow experiments with a maximum value of 96% as well as those obtained from batch experiments. Droplet sizes at the lower and the upper sides of emulsion phases, estimated by using high-speed microscope, were 214 36 m and 415 110 m, respectively.
Asai, Shiho; Toshimitsu, Masaaki; Hanzawa, Yukiko; Suzuki, Hideya; Shinohara, Nobuo; Inagawa, Jun; Okumura, Keisuke; Hotoku, Shinobu; Kimura, Takaumi; Suzuki, Kensuke*; et al.
Journal of Nuclear Science and Technology, 50(6), p.556 - 562, 2013/06
The Sn content in a spent nuclear fuel solution was determined by ICP-MS for its inventory estimation in high-level radioactive waste. An irradiated UO fuel was used as a sample to evaluate the reliability of the methodology. Prior to the measurement, Sn was separated from Te, which causes major isobaric interference in the determination of Sn content, along with highly radioactive coexisting elements using an anion-exchange column. The absence of counts attributed to Te in the Sn-containing effluent indicates that Te was completely removed. After washing, Sn retained on the column was readily eluted with 1 M HNO. The isotope ratios of Sn were successfully determined and showed good agreement with those obtained through ORIGEN2 calculations. The results reported in this paper are the first experimental values of Sn content in the spent nuclear fuel solution originating in spent nuclear fuel irradiated at a nuclear power plant in Japan.
Asai, Shiho; Hanzawa, Yukiko; Suzuki, Hideya; Toshimitsu, Masaaki; Okumura, Keisuke; Shinohara, Nobuo; Kimura, Takaumi; Inagawa, Jun; Suzuki, Kensuke*; Kaneko, Satoru*
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12
Okumura, Keisuke; Asai, Shiho; Hanzawa, Yukiko; Suzuki, Hideya; Toshimitsu, Masaaki; Inagawa, Jun; Okamoto, Tsutomu; Shinohara, Nobuo; Kaneko, Satoru*; Suzuki, Kensuke*
Progress in Nuclear Science and Technology (Internet), 2, p.369 - 374, 2011/10
For accurate inventory estimation of long-lived fission products in LWR spent fuels, a new burn-up chain model and decay data based on the latest nuclear data such as JENDL-4.0 was developed. MVP-BURN with the latest nuclear data was applied to several post irradiation examinations including inventory measurements of Se, Tc, Sn and Cs. One of them is a new measurement by JAEA. From the PIE analyses, it is found that the new PIE data obtained by JAEA is consistent with the other PIE data by different laboratory with different techniques. It is also confirmed that the present calculation results show good agreements with experimental ones within about 10% for productions of Se and Cs. In contrast, amounts of Tc and Sn are overestimated by about 50%. These discrepancies are likely due to the effect of insoluble residue produced during sample dissolution and/or errors of fission yields in the analyses.
Asai, Shiho; Okumura, Keisuke; Hanzawa, Yukiko; Suzuki, Hideya; Toshimitsu, Masaaki; Inagawa, Jun; Kimura, Takaumi; Kaneko, Satoru*; Suzuki, Kensuke*
Proceedings of 14th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2011) (CD-ROM), p.1437 - 1442, 2011/09
Okumura, Keisuke; Asai, Shiho; Hanzawa, Yukiko; Okamoto, Tsutomu; Suzuki, Hideya; Toshimitsu, Masaaki; Inagawa, Jun; Kimura, Takaumi; Suzuki, Kensuke*; Kaneko, Satoru*
Proceedings of 14th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2011) (CD-ROM), p.1443 - 1450, 2011/09
Inventory estimation of long-lived fission products (LLFPs) in high-level radioactive wastes (HLW) from spent nuclear fuels of light water reactors is important for a safety assessment of their disposal. In order to develop an inventory estimation method of difficult-to-measure LLFPs (Se-79, Tc-99, Sn-126, and Cs-135), a parametric study was carried out by using a sophisticated burnup calculation code and data. In the parametric study, fuel specifications and irradiation conditions are changed in the conceivable range. The considered parameters are fuel assembly types (PWR / BWR), U-235 enrichment, moderator temperature, void fraction, power density, and so on. From the calculated results, we clarify the burnup characteristics of the target LLFPs and their possible ranges of generations. Finally, candidates of the key nuclide are proposed for the scaling factor method of HLW.
Naganawa, Hirochika; Suzuki, Hideya*; Yanase, Nobuyuki; Nagano, Tetsushi; Noro, Junji*
Analytical Sciences, 27(3), p.321 - 324, 2011/03
In order to monitor a radioactive nuclide of strontium-90 in seawater around nuclear facilities, a solvent extraction method for collecting Sr(II) in seawater was examined. A reversed-micellar extraction system containing an anionic surfactant AOT and a molecular extractant TODGA in n-hexane was chosen for the extraction of Sr(II) from model solutions of seawater containing 0.5 M NaCl (1 M = 1 mol dm), 0.05 M MgCl, and/or 0.01 M CaCl. The combination of AOT forming reversed micelles and TODGA coordinating with Sr(II) as an organic ligand (extractant) was found to be efficient for the extraction of Sr(II) from the model solutions. The mechanism of the reversed-micellar extraction system was also discussed in the present study.
Asai, Shiho; Hanzawa, Yukiko; Okumura, Keisuke; Suzuki, Hideya; Toshimitsu, Masaaki; Shinohara, Nobuo; Kaneko, Satoru*; Suzuki, Kensuke*
Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.261 - 264, 2010/10
Okumura, Keisuke; Asai, Shiho; Hanzawa, Yukiko; Suzuki, Hideya; Toshimitsu, Masaaki; Inagawa, Jun; Katakura, Junichi; Shinohara, Nobuo; Kaneko, Satoru*; Suzuki, Kensuke*
Proceedings of Joint International Conference of 7th Supercomputing in Nuclear Application and 3rd Monte Carlo (SNA + MC 2010) (USB Flash Drive), 5 Pages, 2010/10
For accurate inventory estimation of long-lived fission products in LWR spent fuels, a new burn-up chain model and decay data based on the latest nuclear data were developed for MVP-BURN. They were applied to three post irradiation examinations including inventory measurements of Se, Tc, Sn and Cs. One of them is new measurements performed by JAEA. From the PIE analyses, it is found that the new measurements by JAEA are consistent with the other PIE data obtained by different laboratory with different techniques. It is also confirmed that the present calculation results show good agreements with experimental ones for Se and Cs within about 10%. In contrast, amounts of Tc and Sn are overestimated by about up to 50%. These discrepancies are likely due to the effect of insoluble residue in the measurements and/or errors of fission yields in the analyses.