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Journal Articles

Solvent extraction of tin in nitric acids; Evaluation of multiple extractants

Ito, Kengo*; Takahashi, Shin*; Kato, Chizu*; Fukutani, Satoshi*; Matsumura, Tatsuro; Fujii, Toshiyuki*

Journal of Radioanalytical and Nuclear Chemistry, 334, p.2467 - 2475, 2025/02

 Times Cited Count:0 Percentile:0.00(Chemistry, Analytical)

In this study, the solvent extraction behavior of tin (Sn), specifically $$^{126}$$Sn, from high-level radioactive waste was evaluated using six different extractants in a HNO$$_{3}$$ system. Among the tested extractants, N,N-Didodecyl-2-hydroxyacetoamide (HAA) exhibited higher efficiency, still not sufficient for industrial implementation. In systems where HCl was added to HNO$$_{3}$$, both tributyl phosphate (TBP) and N,N,N,N'-tetra-2-ethylhexyl diglycolamide (TEHDGA) achieved D$$_{Sn}$$ values greater than 1 at $$>$$ 1 M HCl. However, due to practical challenges in industrial applications, HAA extraction in HNO$$_{3}$$ systems, particularly at low Sn concentrations (0.0008 M), may provide a more effective solution for Sn recovery.

Journal Articles

Solvent extraction behaviors of rhodium and palladium in nitric acid solutions using amide extractants

Ito, Kengo*; Morita, Misaki*; Araki, Yuta*; Kato, Chizu*; Fukutani, Satoshi*; Matsumura, Tatsuro; Fujii, Toshiyuki*

Solvent Extraction Research and Development, Japan, 32(1), p.53 - 62, 2025/00

Rhodium (Rh) and Palladium (Pd) in high-level radioactive waste are primarily fission products. This Study focused on understanding the extraction behavior of these platinum group elements (PGEs) using the novel extractants ${it N,N,N',N',N'',N''}$-hexaoctylnitriloacetamide (HONTA) and alkyl diamideamine (ADAAM). Both extractants showed affinity for Pd, with distribution coefficients significantly exceeding 1, demonstrating their effectiveness in Pd separation. In contrast, the distribution coefficients for Rh were consistently below 10 $$^{-1}$$, indicating low extraction efficiency from nitric acid. However, by leveraging the salting-out effect with calcium nitrate hydrate, a distribution coefficient of $$sim$$570 for Rh was achieved using HONTA. To overcome the difficult back-extraction of PGEs with HONTA, experiments were conducted using HEDTA and thiourea. Back-extraction with HEDTA in high-concentration nitric acid ($$>$$2M) resulted in $$sim$$90% extraction of Pd, while thiourea-based back-extraction with nitric acid yielded over 40% extraction for Rh, with the maximum of 62.7% achieved using hydrochloric acid.

Journal Articles

Solvent extraction of selenium in nitric acid; Evaluation of multiple extractants and proposal of a novel separation process

Ito, Kengo*; Kawakami, Takahiro*; Kato, Chizu*; Fukutani, Satoshi*; Matsumura, Tatsuro; Fujii, Toshiyuki*

Journal of Radioanalytical and Nuclear Chemistry, 333(10), p.5183 - 5189, 2024/10

 Times Cited Count:1 Percentile:62.55(Chemistry, Analytical)

Solvent extraction behaviors of Se (VI) from nitric acid solutions were investigated with multiple extractants used for uranium, plutonium, minor actinides, and rare earthelements separation processes from high-level liquid waste. During the processes, Se remained in the residual aqueous solutions, as all extractants showed distributionratios $$<$$ 1. In contrast, Se showed distribution ratios $$>$$ 1 with $$o$$-phenylenediamine in dilute nitric acid ($$<$$ 2 M HNO$$_{3}$$), octanol as the organic phase, and concentrated nitric acid (8 M HNO$$_{3}$$) for back extraction, suggesting a potential new single separation process and recovery of Se.

Journal Articles

Flexible waste management system for the future application of MA P&T technology to the current high-level liquid waste

Fukasawa, Tetsuo*; Suzuki, Akihiro*; Endo, Yoichi*; Inagaki, Yaohiro*; Arima, Tatsumi*; Muroya, Yusa*; Endo, Keita*; Watanabe, Daisuke*; Matsumura, Tatsuro; Ishii, Katsunori; et al.

Journal of Nuclear Science and Technology, 61(3), p.307 - 317, 2024/03

 Times Cited Count:2 Percentile:27.70(Nuclear Science & Technology)

A flexible waste management system (FWM) is being developed to apply future MA partitioning and transmutation (P&T) technology to current HLLW. This FWM system will store high-level waste (HLLW) in granular form until MA partitioning and transmutation technology is realized. The feasibility of the main process was essentially confirmed by basic experiments and preliminary thermal analysis for granule production by rotary kiln from simulated HLLW and for temporary storage (50 years) of HLW granules at the HLW storage facility, respectively. The granule production experiments revealed that relatively large particles can be produced by the rotary kiln. The results of the thermal analysis showed that the small diameter canisters could be used to safely store the granules at a higher storage density than vitrified HLW. The effectiveness of the FWM system in terms of potential radiotoxicity and repository area was also evaluated, and it was shown that FWM can reduce these factors and has significant advantages in the disposal of HLW generated in current reprocessing plants. Since LWR fuel is stored for a long period of time in Japan and the operation of a reprocessing plant is expected to start soon, the FWM system is considered to be an effective system for reducing the environmental burden of HLW disposal.

Journal Articles

Extraction properties of trivalent rare earth ions from nitric acid using a triamide-amine extractant

Uchino, Seiko*; Narita, Hirokazu*; Kita, Keisuke*; Suzuki, Hideya*; Matsumura, Tatsuro; Naganawa, Hirochika*; Sakaguchi, Koichi*; Oto, Keisuke*

Solvent Extraction Research and Development, Japan, 30(1), p.39 - 46, 2023/00

The extraction of trivalent rare earth ions (RE$$^{3+}$$) from HNO$$_{3}$$ solution using a triamide amine, tris(N,N-di-2-ethylhexyl-ethylamide)amine (DEHTAA), was conducted, and the extraction mechanism was estimated from extraction behavior of HNO$$_{3}$$ and RE$$^{3+}$$ and the relationship between atomic number and extraction percentages (E%) for RE$$^{3+}$$. A DEHTAA molecule dominantly formed a DEHTAA HNO$$_{3}$$ at 1.0 M HNO$$_{3}$$ and a DEHTAA(HNO$$_{3}$$)$$_{2}$$ at 6.0 M HNO$$_{3}$$ in the acid-equilibrated organic phase. This would provide the unique dependence of E% for the light RE$$^{3+}$$ on the HNO$$_{3}$$ concentration, in which the E% value had a minimum and maximum at $$sim$$0.5 M and $$sim$$2 M HNO$$_{3}$$, respectively. The results of the slope analyses for the distribution ratios for RE$$^{3+}$$ suggested that the dominant RE$$^{3+}$$ complex was RE(NO$$_{3}$$)$$_{3}$$DEHTAA(DEHTAA HNO$$_{3}$$) at 1.0 M HNO$$_{3}$$. The E% for RE$$^{3+}$$ decreased from La$$^{3+}$$ to Lu$$^{3+}$$ at 1.0 M HNO$$_{3}$$; on the other hand, those increased from La$$^{3+}$$ to Nd$$^{3+}$$ at 0.25 M and from La$$^{3+}$$ to Sm$$^{3+}$$ and 6.0 M HNO$$_{3}$$.

Journal Articles

Study on the mechanism of radiolytic degradation of an extractant for minor actinides separation

Toigawa, Tomohiro; Kumagai, Yuta; Yamashita, Shinichi*; Ban, Yasutoshi; Matsumura, Tatsuro

UTNL-R-0502 (Internet), 2 Pages, 2022/04

This report summarizes the results obtained in FY2020 at the Electron Linac Facility of the University of Tokyo. The radiolysis process of ${it N,N,N',N',N'',N''}$-hexaoctyl nitrilotriacetamide (HONTA), which is expected to be used as an extractant in a separation process for minor actinides, diluted in dodecane was investigated by pulse radiolysis experiments. The radical cation and the triplet-excited state of HONTA were observed in the nanosecond time region. The transition from the radical cation to the triplet excited state was slowed down by adding electron scavengers, and further, the reactivity of the triplet excited state was also suppressed.

JAEA Reports

Evaluation of the mass transfer coefficients for the minor actinide separation; Evaluation by the single drop method

Sakamoto, Atsushi; Kibe, Satoshi*; Kawanobe, Kazunori*; Fujisaku, Kazuhiko*; Sano, Yuichi; Takeuchi, Masayuki; Suzuki, Hideya*; Tsubata, Yasuhiro; Ban, Yasutoshi; Matsumura, Tatsuro

JAEA-Research 2021-003, 30 Pages, 2021/06

JAEA-Research-2021-003.pdf:1.81MB

Japan Atomic Energy Agency has been developing a solvent extraction process called SELECT to recover minor actinides (MA) from spent nuclear fuel. In the SELECT process, TDdDGA, HONTA, and ADAAM are used as the extractants for MA + Ln corecovery, MA/Ln separation and Am/Cm separation, respectively. These extractants do not contain phosphorus (P), and consist of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N). In this study, in order to give beneficial information for designing flowsheet, the mass transfer coefficients of Ln between HNO$$_{3}$$ solution and TDdDGA or HONTA / n-dodecane solvent were evaluated by the single drop technique. Prior to the evaluation of mass transfer coefficient, we had optimized the structure of the single drop apparatus to improve accuracy of the measurement. Based on the mass transfer coefficients obtained in HNO$$_{3}$$ / TDdDGA-n-dodecane system, Ln behaviors in the counter-current extraction and back-extraction using mixer-settlers and centrifugal contactors were estimated by simple calculation, and they had a good agreement with our previous experimental results. We also confirmed the mass transfer coefficients of Ln in HNO$$_{3}$$ / HONTA - n-dodecane system are under 10$$^{-6}$$ m/s.

Journal Articles

Radiation-induced effects on the extraction properties of hexa-$$n$$-octylnitrilo-triacetamide (HONTA) complexes of americium and europium

Toigawa, Tomohiro; Peterman, D. R.*; Meeker, D. S.*; Grimes, T. S.*; Zalupski, P. R.*; Mezyk, S. P.*; Cook, A. R.*; Yamashita, Shinichi*; Kumagai, Yuta; Matsumura, Tatsuro; et al.

Physical Chemistry Chemical Physics, 23(2), p.1343 - 1351, 2021/01

 Times Cited Count:21 Percentile:83.10(Chemistry, Physical)

The candidate An(III)/Ln(III) separation ligand hexa-$$n$$-octylnitrilo-triacetamide (HONTA) was irradiated under envisioned SELECT (Solvent Extraction from Liquid waste using Extractants of CHON-type for Transmutation) process conditions using a solvent test loop in conjunction with cobalt-60 gamma irradiation. We demonstrate that HONTA undergoes exponential decay with increasing gamma dose to produce a range of degradation products which have been identified and quantified by HPLC-ESI-MS/MS techniques. The combination of HONTA destruction and degradation product ingrowth, particularly dioctylamine, negatively impacts the extraction and back-extraction of both americium and europium ions. The loss of HONTA was attributed to its reaction with the solvent (${it n}$-dodecane) radical cation of ${it k}$(HONTA + R$$^{.+}$$) = (7.61 $$pm$$ 0.82) $$times$$ 10$$^{9}$$ M$$^{-1}$$ s$$^{-1}$$ obtained by pulse radiolysis techniques. However, when this ligand is bound to either americium or europium ions, the observed ${it n}$-dodecane radical cation kinetics increase by over an order of magnitude. This large reactivity increase to additional reaction pathways occurring upon metal-ion binding. Lastly nanosecond time-resolved measurements showed that both direct and indirect HONTA radiolysis yielded the short-lived ($$<$$100 ns) HONTA radical cation as well as a longer-lived ($$mu$$s) HONTA triplet excited state. These HONTA species are important precursors to the suite of HONTA degradation products observed.

Journal Articles

Re-evaluation of radiation-energy transfer to an extraction solvent in a minor-actinide-separation process based on consideration of radiation permeability

Toigawa, Tomohiro; Tsubata, Yasuhiro; Kai, Takeshi; Furuta, Takuya; Kumagai, Yuta; Matsumura, Tatsuro

Solvent Extraction and Ion Exchange, 39(1), p.74 - 89, 2021/00

 Times Cited Count:2 Percentile:7.60(Chemistry, Multidisciplinary)

Absorbed-dose estimation is essential for evaluation of the radiation feasibility of minor-actinide-separation processes. We propose a dose-evaluation method based on radiation permeability, with comparisons of heterogeneous structures seen in the solvent-extraction process, such as emulsions forming in the mixture of the organic and aqueous phases. A demonstration of radiation-energy-transfer simulation is performed with a focus on the minor-actinide-recovery process from high-level liquid waste with the aid of the Monte Carlo radiation-transport code PHITS. The simulation results indicate that the dose absorbed by the extraction solvent from alpha ray depends upon the emulsion structure, and that from beta and gamma ray depends upon the mixer-settler-apparatus size. Non-negligible contributions of well-permeable gamma rays were indicated in terms of the plant operation of the minor-actinide-separation process.

Journal Articles

Study on the mechanism of radiolytic degradation of an extractant for minor actinides separation

Toigawa, Tomohiro; Murayama, Rin*; Kumagai, Yuta; Yamashita, Shinichi*; Suzuki, Hideya; Ban, Yasutoshi; Matsumura, Tatsuro

UTNL-R-0501, p.24 - 25, 2020/12

This report summarizes the results obtained in FY2019 at Electron Linac Facility of University of Tokyo. The radiolysis process of a diglycolamide extractant, which is expected to be used in the separation process of minor actinides (MA), in dodecane and octanol solutions was investigated by pulse radiolysis. As a result, it was suggested that by adding alcohol, the decomposition process of the diglycolamide extractant was different from the decomposition processes in the single solvent of dodecane considered that the decomposition occurred via a radical cation species of the extractant.

Journal Articles

Separation and recovery of long-lived fission products from high level radioactive waste using electrochemical technique

Kanamura, Shohei*; Takahashi, Yuya*; Omori, Takashi*; Nohira, Toshiyuki*; Sakamura, Yoshiharu*; Matsumura, Tatsuro

Denki Kagaku, 88(3), p.289 - 290, 2020/09

no abstracts in English

JAEA Reports

Production of the minor actinide sources using the electrodeposition method

Nakamura, Satoshi; Kimura, Takahiro; Ban, Yasutoshi; Tsubata, Yasuhiro; Matsumura, Tatsuro

JAEA-Technology 2020-009, 22 Pages, 2020/08

JAEA-Technology-2020-009.pdf:2.92MB

Partitioning and transmutation technology division is planning to measure fission rate ratios that contribute to validate nuclear data of minor actinides (MA). For this purpose, MA sources for fission chambers were prepared using electrodeposition method. The radioactivity of each MA source was quantified, and its uncertainty was evaluated. Seven types of MA sources with different radioactivity were prepared using four nuclides of $$^{237}$$Np, $$^{241}$$Am, $$^{243}$$Am, and $$^{244}$$Cm. A $$^{244}$$Cm source solution of which radioactivity was quantified by isotope dilution method was used to prepare working standard sources of $$^{244}$$Cm. The radioactivities were quantified as 1461 Bq, 2179 Bq, and 2938 Bq for $$^{237}$$Np sources, 1.428 MBq for $$^{241}$$Am source, 370.5 kBq and 89.57 kBq for $$^{243}$$Am sources, and 2.327 MBq for $$^{244}$$Cm source with, the uncertainty of 0.35% (1$$sigma$$). This report summarizes the method for preparation and quantification of MA sources, and uncertainty evaluation.

Journal Articles

Effects of diluents on the separation of minor actinides from lanthanides with tetradodecyl-1,10-phenanthroline-2,9-diamide from nitric acid medium

Tsutsui, Nao; Ban, Yasutoshi; Suzuki, Hideya*; Nakase, Masahiko*; Ito, Sayumi*; Inaba, Yusuke*; Matsumura, Tatsuro; Takeshita, Kenji*

Analytical Sciences, 36(2), p.241 - 246, 2020/02

 Times Cited Count:30 Percentile:83.88(Chemistry, Analytical)

To investigate the effective separation of actinides (Ans) from lanthanides (Lns), single-stage batch extraction experiments were performed with a novel extractant, tetradodecyl-1,10-phenanthroline-2,9-diamide (TDdPTDA) with various diluents such as 3-nitrobenzotrifluoride (F-3), nitrobenzene, and ${it n}$-dodecane for Am, Cm, and Lns. The extraction kinetics with TDdPTDA was rapid enough to perform the actual extraction flow sheet. The slopes of the distribution ratio versus TDdPTDA concentration and the distribution ratio versus nitric acid concentration were similar for F-3 and nitrobenzene systems but different from ${it n}$-dodecane system. These differences were attributed to the characteristics of the diluents. This study reveals high distribution ratios of Am (${it D}$ $$_{Am}$$) and Cm (${it D}$ $$_{Cm}$$) for TDdPTDA, with the high separation factors (${it SF}$s) of Am from Lns enough for their separation.

Journal Articles

Sorption properties of aluminum hexacyanoferrate for platinum group elements

Mishima, Ria; Inaba, Yusuke*; Tachioka, Sotaro*; Harigai, Miki*; Watanabe, Shinta*; Onoe, Jun*; Nakase, Masahiko*; Matsumura, Tatsuro; Takeshita, Kenji*

Chemistry Letters, 49(1), p.83 - 86, 2020/01

 Times Cited Count:6 Percentile:24.64(Chemistry, Multidisciplinary)

Separation of platinum group metals (PGMs) from high-level liquid waste generated from the reprocessing of spent nuclear fuels is important to produce good quality vitrified glass for final disposal. A new sorbent, Aluminum hexacyanoferrate (AlHCF), was synthesized and the general sorption behavior of PGMs from concentrated nitric acid was examined. Nitric acid caused substantial elution of AlHCF but the sorption of Pd stabilized the structure. Consequently, Rh was sorbed in the presence of Pd, whereas single Rh sorption caused complete dissolution of AlHCF. Relation between sorbed mount of Pd vs eluted Al and Fe revealed that the elution ratio of Al and Fe was not the same as molar ratio of synthesized AlHCF, indicating the re-sorption of Fe resulted in formation of new structure. The sorption mechanism of PGMs by this new sorbent, AlHCF, not only the simple ion exchange, but also oxidation reduction reaction as well as kinetics play important rule. Understanding the general sorption and dissolution behavior will help improve the sorption performance of PGMs by AlHCF.

Journal Articles

Development of select process for minor actinides partitioning from high level waste

Matsumura, Tatsuro

Kino Zairyo, 40(1), p.60 - 71, 2020/01

no abstracts in English

Journal Articles

No secondary waste recycle technology for rare metals using the hydrophilic extraction with phase transfer phenomena

Tsukahara, Takehiko*; Saga, Kaname*; Suzuki, Hideya*; Matsumura, Tatsuro

Kurin Tekunoroji, 29(12), p.4 - 7, 2019/12

no abstracts in English

Journal Articles

Minor actinides separation by ${it N,N,N',N',N'',N''}$-hexaoctyl nitrilotriacetamide (HONTA) using mixer-settler extractors in a hot cell

Ban, Yasutoshi; Suzuki, Hideya*; Hotoku, Shinobu; Tsutsui, Nao; Tsubata, Yasuhiro; Matsumura, Tatsuro

Solvent Extraction and Ion Exchange, 37(7), p.489 - 499, 2019/11

 Times Cited Count:24 Percentile:63.28(Chemistry, Multidisciplinary)

A continuous counter-current experiment to separate minor actinides (MAs: Am and Cm) was performed with ${it N,N,N',N',N'',N''}$-hexaochyl nitrilotriacetamide (HONTA) as an extractant. Nitric acid of 0.08 M (mol/dm$$^{3}$$) 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 $$geq$$99% by optimizing separation conditions.

Journal Articles

Zr separation from high-level liquid waste with a novel hydroxyacetoamide type extractant

Morita, Keisuke; Suzuki, Hideya; Matsumura, Tatsuro; Takahashi, Yuya*; Omori, Takashi*; Kaneko, Masaaki*; Asano, Kazuhito*

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.464 - 468, 2019/09

High level liquid waste (HLLW) contains several radionuclides with half-lives longer than 10$$^{6}$$ year. For reduce environmental burden of waste disposal, minor actinoids and long-lived fission products will to be partitioned and transmuted. JAEA and Toshiba developed process for recovering Se, Zr, Pd and Cs from HLLW. Solvent extraction for Zr with novel extractant, ${it N,N}$-didodecyl-2-hydroxyacetoamide (HAA) was detailed. The HAA system showed high selectivity for Zr, as indicated by the extraction order of Zr $$>$$ Mo $$>$$ Pd $$>$$ Ag $$approx$$ Sb $$>$$ Sn $$>$$ Lns $$>$$ Fe. The extracted species was determined as Zr(HAA)$$_{3}$$(NO$$_{3}$$)$$_{4}$$(HNO$$_{3}$$)$$_{x}$$. A continuous countercurrent extraction with HAA was applied to a simulated, concentrated HLLW after Pd, Se, and Cs removal, where the quantitative extraction of Zr and Mo was effectively demonstrated.

Journal Articles

Mechanism of palladium(II) adsorption from nitric acid solutions by a styrene-divinylbenzene copolymer functionalized with $$N,N,N$$-trimethylglycine

Suzuki, Tomoya*; Narita, Hirokazu*; Ogata, Takeshi*; Suzuki, Hideya; Matsumura, Tatsuro; Kobayashi, Toru; Shiwaku, Hideaki; Yaita, Tsuyoshi

Solvent Extraction Research and Development, Japan, 26(1), p.11 - 19, 2019/06

 Times Cited Count:3 Percentile:11.66(Chemistry, Multidisciplinary)

The ability of AMP03, a styrene-divinylbenzene copolymer functionalized with $$N,N,N$$-trimethylglycine moieties, to adsorb Pd(II) from HNO$$_{3}$$ solutions was investigated to elucidate the affinity of $$N,N,N$$-trimethylglycine for Pd(II). In the present study, we investigated the mechanism of Pd(II) adsorption by AMP03 by means of adsorption experiments, Fourier Transform Infrared (FT-IR) spectroscopy, and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy.

Journal Articles

Direct temperature-swing extraction of rare-earth elements from acidic solution using the hydrophobic interactions of poly($$N$$-isopropylacrylamide) with diglycolamide-typed ligands

Saga, Kaname*; Suzuki, Hideya; Matsumura, Tatsuro; Tsukahara, Takehiko*

Analytical Sciences, 35(4), p.461 - 464, 2019/04

 Times Cited Count:4 Percentile:13.94(Chemistry, Analytical)

The phase transition-based gelification phenomenon of poly-$$N$$-isopropylacrylamide (PNIPAAm) in aqueous solutions has a great potential in developing new waste-free extraction processes of metal ions. By using hydrophobic diglycolamide-typed ligands in gelification extraction, a one-step complete extraction of all the RE ions from a nitric acid solution was successfully realized.

227 (Records 1-20 displayed on this page)