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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

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.

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


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:1 Percentile:33.83(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

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:0 Percentile:100(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

Extraction of trivalent rare earths and minor actinides from nitric acid with ${it N,N,N',N'}$-tetradodecyldiglycolamide (TDdDGA) by using mixer-settler extractors in a hot cell

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

 Times Cited Count:7 Percentile:25.96(Chemistry, Multidisciplinary)

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$$^{3}$$ 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.

Journal Articles

Theoretical elucidation of Am(III)/Cm(III) separation mechanism with diamide-type ligands using relativistic density functional theory calculation

Kaneko, Masashi; Suzuki, Hideya; Matsumura, Tatsuro

Inorganic Chemistry, 57(23), p.14513 - 14523, 2018/12

 Times Cited Count:4 Percentile:50.9(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)$$_{3}$$]$$^{3+}$$ and [M(ADAAM)(NO$$_{3}$$)$$_{3}$$(H$$_{2}$$O)]. 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)$$_{3}$$]$$^{3+}$$ and [M(ADAAM)(NO$$_{3}$$)$$_{3}$$(H$$_{2}$$O)], 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.

Journal Articles

Uranium-based TRU multi-recycling with thermal neutron HTGR to reduce environmental burden and threat of nuclear proliferation

Fukaya, Yuji; Goto, Minoru; Ohashi, Hirofumi; Yan, X.; Nishihara, Tetsuo; Tsubata, Yasuhiro; Matsumura, Tatsuro

Journal of Nuclear Science and Technology, 55(11), p.1275 - 1290, 2018/11

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

To reduce environmental burden and thread of nuclear proliferation, multi-recycling fuel cycle with High Temperature Gas-cooled Reactor (HTGR) has been investigated. Those problems are solved by incinerating TRans Uranium (TRU) nuclides, which is composed of plutonium and Minor Actinoide (MA), and there is concept to realize TRU incineration by multi-recycling with Fast Breeder Reactor (FBR). In this study, multi-recycling is realized even with thermal reactor by feeding fissile uranium from outside of the fuel cycle instead of breeding fissile nuclide. In this fuel cycle, recovered uranium by reprocessing and natural uranium are enriched and mixed with recovered TRU by reprocessing and partitioning to fabricate fresh fuels. The fuel cycle was designed for a Gas Turbine High Temperature Reactor (GTHTR300), whose thermal power is 600 MW, including conceptual design of uranium enrichment facility. Reprocessing is assumed as existing Plutonium Uranium Redox EXtraction (PUREX) with four-group partitioning technology. As a result, it was found that the TRU nuclides excluding neptunium can be recycled by the proposed cycle. The duration of potential toxicity decaying to natural uranium level can be reduced to approximately 300 years, and the footprint of repository for High Level Waste (HLW) can be reduced by 99.7% compared with GTHTR300 using existing reprocessing and disposal technology. Suppress plutonium is not generated from this cycle. Moreover, incineration of TRU from Light Water Reactor (LWR) cycle can be performed in this cycle.

Journal Articles

Characteristics of TPDN/SiO$$_{2}$$-P adsorbent for MA(III) recovery

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

Journal Articles

Selective Sc recovery from rare earths in nitric acid medium by extraction chromatography

Watanabe, So; Suzuki, Hideya; Goto, Ichiro*; Kofuji, Hirohide; Matsumura, Tatsuro

Nippon Ion Kokan Gakkai-Shi, 29(3), p.71 - 75, 2018/09

Journal Articles

Optimization of disposal method and scenario to reduce high level waste volume and repository footprint for HTGR

Fukaya, Yuji; Goto, Minoru; Ohashi, Hirofumi; Nishihara, Tetsuo; Tsubata, Yasuhiro; Matsumura, Tatsuro

Annals of Nuclear Energy, 116, p.224 - 234, 2018/06

 Times Cited Count:1 Percentile:75.54(Nuclear Science & Technology)

Optimization of disposal method and scenario to reduce volume of High Level Waste (HLW) and the footprint in a geological repository for High Temperature Gas-cooled Reactor (HTGR) has been performed. It was found that HTGR has great advantages to reducing HLW volume and its footprint, which are high burn-up, high thermal efficiency and pin-in-block type fuel, compared with those of LWR and has potential to reduce those more in the previous study. In this study, the scenario is optimized, and the geological repository layout is designed with the horizontal emplacement based on the KBS-3H concept instead of the vertical emplacement based on KBS-3V concept employed in the previous study. As a result, for direct disposal, the repository footprint can be reduced by 20 % by employing the horizontal without change of the scenario. By extending 40 years for cooling time before disposal, the footprint can be reduced by 50 %. For disposal with reprocessing, the number of canister generation can be reduced by 20 % by extending cooling time of 1.5 years between the discharge and reprocessing. The footprint per electricity generation can be reduced by 80 % by extending 40 years before disposal. Moreover, by employing four-group partitioning technology without transmutation, the footprint can be reduced by 90 % with cooling time of 150 years.

Journal Articles

Research on neutron capture cross sections at J-PARC in ImPACT Project

Nakamura, Shoji; Kimura, Atsushi; Hales, B. P.; Iwamoto, Osamu; Tsubata, Yasuhiro; Matsumura, Tatsuro; Shibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*

JAEA-Conf 2017-001, p.15 - 22, 2018/01

Neutron nuclear data of long lived fission products (LLFPs) have been required as basic data for the technology of reduce environmental impact involved in high level radioactive wastes (HLW). The innovative large project called by "Impusing Paradigm Change through Disruptive Technologies Program: ImPACT" have been started from October, 2014. In the ImPACT project, some research groups of JAEA engaged in the Project No.2 (Nuclear Reaction Data Measurements), and have started measurements of neutron capture cross-section at J-PARC/MLF/ANNRI. In our research, we selected cesium-135 ($$^{135}$$Cs) nuclide (half life: 2.3$$times$$10$$^{6}$$ yr.) among LLFPs in the HLW, and decided to measure the neutron capture cross-sections of $$^{135}$$Cs. When measurement, the $$^{135}$$Cs sample might contained cecium-137 ($$^{137}$$Cs) as impurities because it's impossible to chemically separate each other. To measure the cross-sections of $$^{135}$$Cs, there should be also needed to know the cross-sections of $$^{137}$$Cs. In this work, sample maintenance also has been examined especially for selen-79 ($$^{79}$$Se) nuclide among LLFPs having difficulty in sample preparations. In this oral session, the outline of our research project will be presented together with a research motivation, situations of past reported data, total schedules, progress, future plans, and some of high light data for neutron capture cross-section measurements.

Journal Articles

Continuous extraction and separation of Am(III) and Cm(III) using a highly practical diamide amine extractant

Suzuki, Hideya; Tsubata, Yasuhiro; Kurosawa, Tatsuya*; Sagawa, Hiroshi*; Matsumura, Tatsuro

Journal of Nuclear Science and Technology, 54(11), p.1163 - 1167, 2017/11

 Times Cited Count:11 Percentile:9.09(Nuclear Science & Technology)

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.

Journal Articles

Solvent extraction of uranium with ${it N}$,${it N}$-di(2-ethylhexyl)octanamide from nitric acid medium

Tsutsui, Nao; Ban, Yasutoshi; Sagawa, Hiroshi; Ishii, Sho; Matsumura, Tatsuro

Solvent Extraction and Ion Exchange, 35(6), p.439 - 449, 2017/08

 Times Cited Count:3 Percentile:77.12(Chemistry, Multidisciplinary)

Solvent extraction of uranium from a nitric acid medium was performed with ${it N}$,${it N}$-di(2-ethylhexyl)octanamide (DEHOA) by a single-stage batch method, and the distribution ratio equation of U(VI) was derived as $${it D}_{rm U}$$ = 1.1$$[rm NO^{-}_{3}]^{1.6}_{rm aq}[{rm DEHOA}]^{2}_{rm org}$$. Furthermore, the nitric acid distribution was also evaluated, and the distribution ratio equation $${it D}_{rm H}$$ = 0.12$$[rm H^{+}]^{0.76}_{rm aq}[{rm DEHOA_{rm Free}}]_{rm H}$$ was obtained. Batch experiments to evaluate the time dependence of U(VI) extraction and the U(VI) loading capacity of DEHOA were also performed. It was revealed that U(VI) extraction by DEHOA reached an equilibrium state within a few minutes, and the loading capacity was 0.71 mol/dm$$^{3}$$ (M) when the concentrations of DEHOA and nitric acid were 1.5 and 3.0 M, respectively.

JAEA Reports

Countercurrent extraction/stripping experiments using TDdDGA solvent extractant in a centrifugal contactor system,2; Evaluation on the improved flowsheet for MA recovery

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.

Journal Articles

High-performance alkyl diamide amine and water-soluble diamide ligand for separating of Am(III) from Cm(III)

Suzuki, Hideya; Tsubata, Yasuhiro; Matsumura, Tatsuro

Analytical Sciences, 33(2), p.239 - 242, 2017/02

 Times Cited Count:7 Percentile:51.56(Chemistry, Analytical)

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.

Journal Articles

Uranium and plutonium extraction by ${it N,N}$-dialkylamides using multistage mixer-settler extractors

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

Procedia Chemistry, 21, p.156 - 161, 2016/12

 Times Cited Count:1 Percentile:26.04

A continuous counter-current experiment was carried out to demonstrate the validity of a process using ${it N,N}$-dialkylamides for recovering U and Pu. This process consisted of two cycles, and the 1st cycle and the 2nd cycle employed ${it N,N}$-di(2-ethylhexyl)-2,2-dimethylpropanamide and ${it N,N}$-di(2-ethylhexyl)butanamide as extractants, respectively. The feed solution for the 1st cycle was 5.1 mol/dm$$^{3}$$ (M) nitric acid containing 0.92 M U, 1.6 mM Pu, and 0.6 mM Np. The raffinate collected in the 1st cycle was used as the feed for the 2nd cycle. The ratios of U recovered in the U fraction and U-Pu fraction were 99.1% and 0.8%, respectively. The ratio of Pu recovered in the U-Pu fraction was 99.7%. The concentration ratio of U with respect to Pu in the U-Pu fraction was 9, and this indicated that Pu was not isolated. The decontamination factor of U with respect to Pu in the U fraction was obtained as 4.5$$times$$10$$^{5}$$. These results supported the validity of the proposed process.

Journal Articles

The Separation mechanism of Am(III) from Eu(III) by diglycolamide and nitrilotriacetamide extraction reagents using DFT calculations

Kaneko, Masashi; Watanabe, Masayuki; Matsumura, Tatsuro

Dalton Transactions, 45(43), p.17530 - 17537, 2016/11


 Times Cited Count:19 Percentile:13.93(Chemistry, Inorganic & Nuclear)

Relativistic density functional calculations were applied to study the separation behaviors of Am(III) ion from Eu(III) ion by diglycolamide (DGA) and nitrilotriacetamide (NTA) ligands in order to understand the difference in the separation mechanism of their reagents. The complexation reaction was modeled on the basis of previous experimental studies. The calculated energies based on stabilization by complex formation at the ZORA-B2PLYP/SARC level predicted that the DGA reagent preferably coordinated to Eu(III) ion when compared with Am(III) ion. In contrast, the NTA reagent selectively coordinated to Am(III) ion when compared with Eu(III) ion. These results reproduced the experimental selectivity of DGA and NTA ligands toward Eu(III) and Am(III) ions. Mulliken's population analyses implied that the difference in the contribution of the bonding property between the f-orbital of Am and donor atoms determined the comparative stability of Eu and Am complexes.

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