Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Hagiwara, Hiroki; Takaku, Atsushi*; Sagawa, Hiroshi*; Kanno, Futoshi*; Ito, Azusa; Ando, Taichi*; Ichihara, Masatsugu*; Watanabe, Yusuke; Koarai, Kazuma; Kato, Jun; et al.
Proceedings of Waste Management Symposia 2026 (WM2026) (Internet), 7 Pages, 2026/03
Sasaki, Yuji; Kaneko, Masashi; Matsumiya, Masahiko*; Kumagai, Yuta
Journal of Molecular Liquids, 441, p.129013_1 - 129013_10, 2026/01
This study determined extraction and back-extraction conditions for the mutual separation of three light PGMs, Ru, Rh, and Pd. Results revealed that reagents containing soft N and S donor atoms efficiently extract and strip Pd through solvation. In comparison, Ru and Rh undergo ion-pair extraction, requiring both anionic metal species and cationic extractants. These essential chlorinated PGM anions and protonated extractants having amino N atoms are present in HCl media. D(Ru) and D(Rh) values of approximately 100 and 10, respectively, were obtained using nitrilo-triacet-amide (NTAamide), which exhibits tetradentate coordination. Refluxing in 3-6 M HCl at 250 
C, a condition that promotes the formation of highly chlorinated PGM anionic species, increased D(Ru) and D(Rh). Based on these findings, a flow diagram for the mutual separation of three PGMs was developed.
Hotoku, Shinobu; Ban, Yasutoshi; Konda, Miki; Kitatsuji, Yoshihiro
JAEA-Technology 2025-009, 33 Pages, 2025/11
JAEA-Technology-2025-009.pdf:1.9MB
High-level liquid waste (HLLW) produced from reprocessing of spent nuclear fuels contains heat generating nuclides such as Sr-90, Y-90, Cs-137, Ba-137m, and Am-241. Separation and recovery of these nuclides lead to reduce the volume and toxicity of high-level waste. Furthermore, the recovered nuclides and elements could be utilized as resources after purification. In this test, Sr separation by extraction chromatography using Sr resin and Pb resin, Cs separation by co-precipitation using ammonium phosphomolybdate (AMP), and Am separation by solvent extraction using alkyl diamideamine (ADAAM) were carried out, cold tests were performed for the separation of Cs and Sr in a nitric acid solution. Based on the results, hot tests were performed using dissolution solutions of spent fuel at the Nuclear Fuel Cycle Safety Engineering Research Facility (NUCEF), and each component contained in the separated solution was analyzed. In the Sr separation by extraction chromatography, most of Sr was separated from other elements using 8 mol/L nitric acid for absorption and 0.02 mol/L nitric acid for elution. In the separation of Cs, more than 99.9% of Cs was selectively co-precipitated by adding AMP to the HLLW, in which nitric acid concentration was adjusted to 3.1 mol/L. In solvent extraction of Am by ADAAM, 81.4% of Am-241 was recovered by a single stage batch experiment. Since Sr, Cs, and Am were properly separated and recovered from HLLW, the effectiveness of the present separation method was successfully demonstrated.
Chaerun, R. I.; Sato, Junya; Hiraki, Yoshihisa; Yoshida, Yukihiko; Sato, Tsutomu*; Osugi, Takeshi
Construction and Building Materials, 500, p.144270_1 - 144270_10, 2025/11
Times Cited Count：1 Percentile：18.61(Construction & Building Technology)Alkali-activated materials (AAMs), particularly those derived from metakaolin, have gained significant attention as sustainable binders for hazardous waste immobilisation, owing to their dense microstructure and chemical durability. Their amorphous aluminosilicate framework enables effective encapsulation of hazardous materials and reduces environmental risks. However, maintaining the stability of this amorphous network is challenging, particularly when sodium (Na
)-rich precursors are used, as excess Na) promotes crystallisation and compromises matrix integrity. This study systematically investigates the influence of Na) concentration on the structural stability of metakaolin-based AAMs activated primarily with potassium (K)). The objective is to identify the threshold Na incorporation level that preserves the amorphous structure and maintains chemical stability. Transmission electron microscopy (TEM), Raman spectroscopy, and thermodynamic modelling were employed to examine the structural evolution of K-AAMs across a range of Na:K molar ratios. The results reveal that higher Na:K ratios induce nanopore formation and early crystallisation of Na-rich zeolitic phases, which can reduce matrix stability. In contrast, an optimal Na:K ratio was identified that maintains the amorphous network and preserves the aluminosilicate framework. These findings provide valuable insights into optimising K-AAMs for advanced, durable waste encapsulation technologies.
Sasaki, Yuji; Kaneko, Masashi; Kumagai, Yuta; Ban, Yasutoshi
Progress in Nuclear Science and Technology (Internet), 8, p.202 - 204, 2025/09
Two extractants and a masking agent of TODGA (TetraOctyl-DiGlycolAmide), ADAAM (AlkylDiAmideAMine), and DTBA (DiethyleneTriamine-triacetic-BisAmide) were developed in JAEA. TODGA can extract both trivalent actinides (An) and lanthanides (Ln), DTBA may separate An from Ln, and ADAAM has high separation factor (SF: 6) for Am/Cm. The suitable conditions for the extraction, separation and isolations of An from Ln are investigated using these reagents. In this work, we show the basic information on extraction behavior of An and Ln using TODGA, DTBA and ADAAM and propose the suitable aqueous and the organic conditions for An+Ln extraction, An/Ln separation and Am/Cm separation.
Sasaki, Yuji; Kaneko, Masashi; Kumagai, Yuta; Ban, Yasutoshi
Solvent Extraction and Ion Exchange, 43(5-6), p.768 - 784, 2025/06
Times Cited Count：0 Percentile：0.00(Chemistry, Multidisciplinary)We developed a method called the alkyl-diamide amine (ADAAM(EH))-diethylenetriamine-triacetic acid-bis(diethylacetamide) (DTBA) technique for separating actinide (An) and lanthanide (Ln) elements from high-level liquid waste. ADAAM(EH) exhibits a high separation factor (SF) not only for Am/Cm but also for light/heavy Ln under acidic conditions (1.5 M HNO
). Consequently, Am can be separated from Cm as well as from middle Ln (Sm, Eu, and Gd) using ADAAM(EH) as an extractant. DTBA enables the stripping of Am and potentially separates it from Ln in the organic phase at low pH (
2). The lowest SF among the light Ln, observed for Nd/Am, exceeded 10, indicating that Am can be separated from light Ln by stripping using DTBA from the ADAAM(EH) extraction solvent. The density functional theory calculations for understanding the coordination bond properties of metal-DTBA complexes are performed, which supported higher affinity of DTBA toward Am than Nd.
Minowa, Kazuki*; Watanabe, So; Nakase, Masahiko*; Takahatake, Yoko; Miyazaki, Yasunori; Ban, Yasutoshi; Matsuura, Haruaki*
Nuclear Instruments and Methods in Physics Research B, 556, p.165496_1 - 165496_6, 2024/11
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)In this study, X-ray absorption near edge structure (XANES) spectral analysis and column experiments were used to verify the selectivity of rare earth (RE) ions by alkyl diamide amine (ADAAM) adsorbent. In addition, the interactions between the N atoms of ADAAM and RE ions were evaluated to determine whether any of the RE ions are a valid simulant for developing a mutual separation process for minor actinides (MAs) in highly radioactive liquid waste. It was confirmed that La and Ce interacted with the amine N atom of ADAAM and they showed a peak shift of the N-K edge XANES spectrum; this finding suggested that a soft interaction is an essential factor influencing ion selectivity. Therefore, the selection factor of RE ions by ADAAM adsorbent was similar to that of MAs. It was concluded that RE ions are reasonable species to simulate MAs.
Sasaki, Yuji; Kaneko, Masashi; Ban, Yasutoshi; Suzuki, Hideya*
Journal of Nuclear Science and Technology, 61(7), p.883 - 893, 2024/07
Times Cited Count：6 Percentile：63.53(Nuclear Science & Technology)The mutual separation of Am and Cm is conducted using an alkyl-diamide amine (ADAAM) extractant. ADAAM exhibits extremely high separation factor with respect to Am and Cm separation (5.9) in a nitric acid-
-dodecane system. The batch-wise multistage extractions are performed using a system containing 0.2 M ADAAM and 1.5 M nitric acid. In this multistage extraction, an organic solvent give 96.5% and 1.06% yields of Am and Cm. After the mutual separation of Am and Cm, an additional extraction step is included to reduce the volumes of these aqueous and organic phases. Taking these steps, Am and Cm can be recovered in just two or three stages in the aqueous phases.
Kinoshita, Ryoma; Sasaki, Yuji; Kaneko, Masashi; Matsumiya, Masahiko*; Shinoku, Kota*; Shiroishi, Hidenobu*
Hydrometallurgy, 222, p.106159_1 - 106159_12, 2023/10
Times Cited Count：5 Percentile：23.84(Metallurgy & Metallurgical Engineering)Solvent extraction is conducted using a total of 20 metals revealing high stability constants with Cl and hexahexyl-nitrilotriacetamide (NTAamide(C6)) extractant. The metals used here may behave as anions at high Cl concentrations, and NTAamide(C6), which contains a tertiary N atom, is protonated under acidic conditions. Most of the metal ions in this study display higher distribution ratios (D(M)) from HCl than those from HNO, and exhibit 1:1 stoichiometries with NTAamide. Following the experimental results, the association constants and distribution coefficients of the group 12 elements are calculated via ion-pair extraction modeling using density functional theory calculations, and the simulations of D yield calculated values with the same trend as that of the measured values.
Sasaki, Yuji; Kaneko, Masashi; Ban, Yasutoshi; Kinoshita, Ryoma; Matsumiya, Masahiko*; Shinoku, Kota*; Shiroishi, Hidenobu*
Analytical Sciences, 39(9), p.1575 - 1583, 2023/09
Times Cited Count：5 Percentile：31.82(Chemistry, Analytical)Extraction of Rh from HCl can be performed by NTAamide(C6) (hexahexyl-nitrilotriacetamide) and other related compounds into n-dodecane. We use ion-pair extraction of anionic species of Rh-chloride and protonated extractant. Rh behave as anion in hydrochloric acid and the tertiary nitrogen atom in extractant may be protonated to produce the quaternary amine in acidic condition. From the present work, the maximum distribution ratio of Rh(III) is 16. The D(Rh) values are changeable during preparation of the aqueous solutions because different Rh-Cl-H
O complexes are formed in HCl media and show the slow exchange rate between Cl and HO. Using the UV spectrum, Rh-chloride solution having the peak of spectrum at 504 nm can be extracted effectively, where RhCl
(HO)
and RhCl
(H
O)
exist mainly from DFT calculation. Stoichiometry of one-one complex of Rh and NTAamide is obtained from slope analysis, and 85 mM of concentrated Rh ion can be extracted.
Suzuki, Hideya*; Ban, Yasutoshi
Analytical Sciences, 39(8), p.1341 - 1348, 2023/08
Times Cited Count：5 Percentile：31.82(Chemistry, Analytical)The Japan Atomic Energy Agency (JAEA) has proposed the Solvent Extraction from Liquid waste using Extractants of CHON-type for Transmutation (SELECT) process by solvent extraction as a new separation technology to recover minor actinides (MA) from high-level liquid waste (HLLW) produced by spent fuel reprocessing. The MA separation in the SELECT process comprises the batch recovery of MA and rare earths (RE) from HLLW, MA/RE separation, and Am/Cm separation. Three highly practical extractants are used in the MA separation. Furthermore, this flow configuration facilitates the preparation of nitric acid concentrations in the aqueous phase. However, the separation factor between Cm and Nd in the MA/RE separation is small (
= 2.5), requiring many extraction stages for continuous extraction in a mixer-settler. Therefore, this study investigated the separation of only Am from an aqueous nitric acid solution containing MA (Am and Cm) and RE using an organic phase mixed with two extractants alkyl diamideamine with 2-ethylhexyl alkyl chains (ADAAM(EH)) and hexa-n-octylnitrilotriacetamide (HONTA) used in the SELECT process. Under high-concentration nitric acid conditions, Am and La, Ce, Pr, Nd (light lanthanides) were extracted in the ADAAM(EH) + HONTA mixed solvent, whereas Cm, medium, and heavy lanthanides, and Y were partitioned in the aqueous phase. Subsequently, only light lanthanides could be back extracted from the ADAAM(EH) + HONTA mixture solvent containing Am and light lanthanides in low nitric acid concentrations. Furthermore, Am could be easily stripped with 0.2 M or 5 M nitric acid. This method does not require the mutual separation of Cm and Nd, which have low separation factors. Am can be efficiently separated by one extraction and two back-extractions, reducing the number of steps in the SELECT process.
Kaneko, Masashi; Suzuki, Hideya; Matsumura, Tatsuro
Inorganic Chemistry, 57(23), p.14513 - 14523, 2018/12
Times Cited Count：27 Percentile：78.57(Chemistry, Inorganic & Nuclear)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.
Sasaki, Yuji; Morita, Keisuke; Ito, Keisuke; Suzuki, Shinichi; Shiwaku, Hideaki; Takahashi, Yuya*; Kaneko, Masaaki*; Omori, Takashi*; Asano, Kazuhito*
Proceedings of International Nuclear Fuel Cycle Conference (GLOBAL 2017) (USB Flash Drive), 4 Pages, 2017/09
no abstracts in English
Ogura, K.*; Asano, Masaharu; Yasuda, Nakahiro*; Yoshida, Masaru
Nuclear Instruments and Methods in Physics Research B, 185(1-4), p.222 - 227, 2001/12
Times Cited Count：33 Percentile：88.28(Instruments & Instrumentation)no abstracts in English
Okada, Makoto*; Watanabe, So; Nakase, Masahiko*; Ban, Yasutoshi; Shiwaku, Hideaki; Matsuura, Haruaki*
no journal, ,
no abstracts in English
Hiraki, Yoshihisa; Saito, Toshimitsu*; Kakuda, Ayaka; Osugi, Takeshi; Sone, Tomoyuki; Kuroki, Ryoichiro; Kudo, Isamu*; Elakneswaran, Y.*; Sato, Tsutomu*
no journal, ,
no abstracts in English
Osugi, Takeshi
no journal, ,
no abstracts in English
Suzuki, Hideya*; Ban, Yasutoshi; Tsubata, Yasuhiro; Hotoku, Shinobu; Toigawa, Tomohiro; Tsutsui, Nao; Shibata, Mitsunobu*; Kurosawa, Tatsuya*; Kawasaki, Tomohiro*; Matsumura, Tatsuro
no journal, ,
The Japan Atomic Energy Agency has been studying partitioning and transmutation (P&T) systems. In the P&T, the separation of minor actinides (MAs) from the chemically similar lanthanides is the key step. After MAs are separated from high-level waste, the mutual separation of Am and Cm (Am/Cm separation) can be conducted. Therefore, the removal of the pyrogenic Cm nuclide would reduce the difficulties associated with MA-fuel fabrication. However, Am/Cm separation is very challenging because the two elements have similar chemical and physical properties. Highly practical a new reagent, called ADAAM have been developed. The Am is subsequently selectively stripped from the light lanthanides. As a result, Am was separated with high efficiency.
Suzuki, Hideya*; Ban, Yasutoshi; Tsubata, Yasuhiro; Tsutsui, Nao; Toigawa, Tomohiro; Kurosawa, Tatsuya*; Shibata, Mitsunobu*; Kawasaki, Tomohiro*; Matsumura, Tatsuro
no journal, ,
The Japan Atomic Energy Agency (JAEA) has been studying partitioning technology. Recently, JAEA proposed a new liquid-liquid extraction technology called SELECT process to separate minor actinide (MA) from high-level liquid waste for transmutation. In this process, new extractants (HONTA, ADAAM) with highly practical and high extraction ability for MA was developed. A mixed solvent of HONTA and ADAAM was tested for mutual separation of MA and rare earth elements (RE). In this test, separation of MA and RE was achieved with very high yield. Furthermore, Americium (Am) and Curium (Cm) were separated efficiently with high separation factor values.
Matsumura, Tatsuro; Ban, Yasutoshi; Suzuki, Hideya; Tsubata, Yasuhiro; Hotoku, Shinobu; Tsutsui, Nao; Suzuki, Asuka; Toigawa, Tomohiro; Kurosawa, Tatsuya*; Shibata, Mitsunobu*; et al.
no journal, ,
PUREX process was established for industrial scale reprocessing plant. TRUEX and the 4 group separation were developed for partitioning of minor actinides from HLW, and demonstrated using genuine HLW. Although the extractants for the processes have excellent performance, the molecules contain phosphorus which could be cause for the secondary waste from the solvent extraction processes. To minimize the radioactive waste, we have conducted research and development of the new reprocessing and MA separation processes using innovative extractants in accord with CHON principle. The extractants for reprocessing process are monoamides as alternative extractants for TBP. For An(III)+RE recovery process, we developed TDdDGA. HONTA and ADAAM were developed for An(III)/RE separation process and Am/Cm separation process respectively. The separation performances of the flowsheets were evaluated by continuous extraction tests using simulated and genuine spent fuel and high level liquid waste.
