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Yamamoto, Yusuke*; Watanabe, Takahiro; Niwa, Masakazu; Shimada, Koji
JAEA-Testing 2023-003, 67 Pages, 2024/02
JAEA-Testing-2023-003.pdf:4.63MB
A long-term geosphere stability for geological disposal is evaluated by the past geological environmental changes and modern conditions. Stable hydrogen and oxygen isotope ratios (
D, 
O) of geological samples are useful information to estimate the past environmental changes and modern conditions. Recently, the thermal conversion elemental analyzer and isotope ratio mass spectrometer (TC-EA/IRMS) were installed in the Tono Geoscience Center for D and O measurements of geological samples. In this study, we reported analytical methods of D and O using international standard reference materials. In addition, evaluation tests of uncertainty by repeated analyses of the standards were performed using the TC-EA/IRMS. Furthermore, the D and O analyses by the TC- EA/IRMS were also applied to fault rock samples.
(M = Gd, Np) by the reaction of MN with Pd and chlorination of MPd using cadmium chlorideHayashi, Hirokazu; Shibata, Hiroki; Sato, Takumi; Otobe, Haruyoshi
Journal of Radioanalytical and Nuclear Chemistry, 332(2), p.503 - 510, 2023/02
Times Cited Count：0 Percentile：0.01(Chemistry, Analytical)The formation of MPd (M = Gd, Np) by the reaction of MN with Pd at 1323 K in Ar gas flow was observed. Cubic AuCu
-type GdPd
(
= 0.4081 
0.0001 nm) and NpPd ( = 0.4081 0.0001 nm) were identified, respectively. The product obtained from the reaction of NpN with Pd contained additional phases including the hexagonal TiNi-type NpPd. Chlorination of the MPd (M = Gd, Np) samples was accomplished by the solid-state reaction using cadmium chloride at 673 K in a dynamic vacuum. Pd-rich solid solution phase saturated with Cd and an intermetallic compound PdCd were obtained as by-products of MCl formation.
Sato, Tetsuya; Nagame, Yuichiro*
Nihon Butsuri Gakkai-Shi, 78(2), p.64 - 72, 2023/02
The study of the chemistry of superheavy elements, which are located in the heavy extremes of the periodic table, has made considerable progress over the past 20 years, and new approaches based on various ideas have recently been developed. Research groups in Japan have also made significant contributions to the development of research on superheavy elements. Recently, notable results have been reported for the transactinide elements rutherfordium (element 104), dubnium (element 105), and seaborgium (element 106), and the heavy actinides with atomic numbers exceeding 100. The review will focus on the recent main results of these elements. This review outlines the main recent results and touches on future prospects.
Hirata, Sakiko*; Kusaka, Ryoji; Meiji, Shogo*; Tamekuni, Seita*; Okudera, Kosuke*; Hamada, Shoken*; Sakamoto, Chihiro*; Honda, Takumi*; Matsushita, Kosuke*; Muramatsu, Satoru*; et al.
Inorganic Chemistry, 62(1), p.474 - 486, 2023/01
Times Cited Count：0 Percentile：0.01(Chemistry, Inorganic & Nuclear)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
) from HNO
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 and RE and the relationship between atomic number and extraction percentages (E%) for RE. A DEHTAA molecule dominantly formed a DEHTAA HNO at 1.0 M HNO and a DEHTAA(HNO)
at 6.0 M HNO in the acid-equilibrated organic phase. This would provide the unique dependence of E% for the light RE on the HNO concentration, in which the E% value had a minimum and maximum at 
0.5 M and 2 M HNO, respectively. The results of the slope analyses for the distribution ratios for RE suggested that the dominant RE complex was RE(NO)DEHTAA(DEHTAA HNO) at 1.0 M HNO. The E% for RE decreased from La to Lu at 1.0 M HNO; on the other hand, those increased from La to Nd at 0.25 M and from La to Sm and 6.0 M HNO.
G
tz, M.*; Yakushev, A.*; Gtz, S.*; Di Nitto, A.*; D
llmann, Ch. E.*; Asai, Masato; Kindler, B.*; Krier, J.*; Lommel, B.*; Nagame, Yuichiro*; et al.
Radiochimica Acta, 110(2), p.75 - 86, 2022/02
Times Cited Count：2 Percentile：31.78(Chemistry, Inorganic & Nuclear)The study of volatile superheavy element carbonyl complexes requires more efficient methods because the yield of transactinide elements decreases with increasing atomic number. This is achieved by using a newly developed double chamber system to separate the recoil chamber and the reaction one, thereby avoiding the decomposition of reactive molecules by the projectile ion beam, which hinders the synthesis of carbonyl complexes. The feasibility of this method was verified by synthesizing 5d metal short-lived isotopes as homologous element isotopes of the light transactinide elements Sg, Bh, Hs, and Mt at the Japan Atomic Energy Agency tandem accelerator and conducting model experiments.
Ito, Tatsuya; Osugi, Haruka*; Osawa, Naoki*; Takahashi, Tadayuki*; Kim, S.-Y.*; Nagaishi, Ryuji
Analytical Sciences, 38(1), p.91 - 97, 2022/01
Times Cited Count：2 Percentile：15.48(Chemistry, Analytical)A novel ionic liquid (IL) functionalized with thiodiglycol amic acid containing a soft S donor was synthesized for the effective and efficient extraction of platinum group metals (Ru, Rh, and Pd) from aqueous nitric acid solutions, such as high-level radioactive liquid waste (HLLW). The IL allowed a rapid extraction of Pd(II) with an extraction ratio of approximately 100%. The extractions of Ru(III) and Rh(III) by the IL were slower than that of Pd(II), but the rates were accelerated by temperature elevation. The extractions of Ru(III) and Rh(III) at 50
C reached equilibrium within 4 and 8 h, respectively, with the extraction ratios of over 90% without assisting agents or other methods for the extraction system. Furthermore, the IL could extract more than 90% of Ru(III), Rh(III), and Pd(II) from the simulated HLLW within 2 h at 50C.
Kaneko, Masashi
Nihon Genshiryoku Gakkai-Shi ATOMO
, 64(1), p.30 - 34, 2022/01
Partitioning of minor actinides from rare earths is one of the most important techniques to develop group separation of high-level radioactive liquid waste. In this issue, the results of prediction of separation performance between minor actinides and rare earths observed in solvent extraction and the separation mechanism by means of using density functional theory are explained.
Sasaki, Yuji; Kaneko, Masashi; Ban, Yasutoshi; Matsumiya, Masahiko*; Nakase, Masahiko*; Takeshita, Kenji*
Separation Science and Technology, 57(16), p.2543 - 2553, 2022/00
Times Cited Count：3 Percentile：29.84(Chemistry, Multidisciplinary)The mutual separation of actinides (An) from lanthanides (Ln) using the masking agent of DTPA (diethylenetriamine-pentaacetic acid) or DTBA (diethylenetriamine-triacetic acid-bis(diethylacetamide)) in the aqueous phase through DGA extraction, referring TALSPEAK method, is focused. We investigate to obtain the same separation performance using commercially available DTPA on that using DTBA. In this work, we select lactic acid (LA) of pH buffer from 10 organic acids and ethylenediamine (ED) for the pH adjustment. Almost the same D and SF values are obtained among the conditions: TODGA-DTPA-LA-NaOH, TODGA-DTPA-LA-ED, and TODGA-DTBA-LA. The experimental results using batchwise multi-stage extractions show the average yields of Ln (La to Gd) and Am to be 3.73 and 98.1% in the aqueous phase using DGA-DTPA-LA-ED, to be 3.1 and 97.0% using DGA-DTPA-LA-NaOH, and to be 1.61 and 98.7% using DGA-DTBA-LA.
Sasaki, Yuji; Kaneko, Masashi; Matsumiya, Masahiko*; Nakase, Masahiko*; Takeshita, Kenji*
Solvent Extraction and Ion Exchange, 40(6), p.620 - 640, 2022/00
Times Cited Count：1 Percentile：14.86(Chemistry, Multidisciplinary)Owing to the chemical behavior of trivalent lanthanide and actinide ions with similar ionic radii, realizing this separation is still challenging. All lanthanides, Am, and Cm can be extracted using diglycolamide (DGA), and relatively high An/Ln separation efficiencies have been obtained using diethylenetriamine-triacetic-bisamide (DTBA). To improve the previous results as well as the separation conditions, we used organic acids for pH adjustment. The advantages of this modification included low HNO, DTBA concentrations and pH stability owing to the addition of lactic acid. Under these modified conditions, the recovery rates observed were as follows: 97.1% for Nd with the co-existence of 1.59% Am in organic phase, and 98.4% for Am with the co-existence of 2.95% Nd in aqueous phase.
Nankawa, Takuya; Sekine, Yurina
Isotope News, (778), p.34 - 35, 2021/12
A high-performance adsorbent was synthesized by reaction of waste bone and sodium hydrogen carbonate. Since waste bones are inexpensive and well-supplied materials, it has the potential to be used for a wide range of decontamination and removal of harmful metals.
-violation studies on superheavy molecules; Theoretical and experimental perspectivesMitra, R.*; Prasannaa, V. S.*; Garcia Ruiz, R. F.*; Sato, Tetsuya; Abe, Minori*; Sakemi, Yasuhiro*; Das, B. P.*; Sahoo, B. K.*
Physical Review A, 104(6), p.062801_1 - 062801_9, 2021/12
Times Cited Count：2 Percentile：24.82(Optics)We provide detailed theoretical studies of quantities relevant to the electron electric dipole moment (eEDM) and nucleus-electron scalar-pseudoscalar interactions in diatomic molecules containing superheavy lawrencium nuclei. The sensitivity to parity and time (or, equivalently, ) reversal violating properties is studied for different neutral and ionic molecules. The effective electric fields in these systems are found to be about 34 times larger than other known molecules on which eEDM experiments are being performed. Similarly, these superheavy molecules exhibit an enhancement of more than 3 times for -violating scalar-pseudoscalar nucleus-electron interactions. Our preliminary analysis using the Woods-Saxon nuclear model also demonstrates that these results are sensitive to the diffuse surface interactions inside the Lr nucleus.
Yakushev, A.*; Lens, L.*; Dllmann, C. E.*; Block, M.*; Nagame, Yuichiro*; Sato, Tetsuya; Toyoshima, Atsushi*; 42 of others*
Frontiers in Chemistry (Internet), 9, p.753738_1 - 753738_9, 2021/11
Times Cited Count：10 Percentile：63.67(Chemistry, Multidisciplinary)Nihonium (Nh, element 113) and flerovium (Fl, element 114) are the first superheavy elements in which the 7p shell is occupied. High volatility and inertness were predicted for Fl due to the strong relativistic stabilization of the closed 7p
sub-shell, which originates from a large spin-orbit splitting between the 7p and 7p
orbitals. One unpaired electron in the outermost 7p sub-shell in Nh is expected to give rise to a higher chemical reactivity. Theoretical predictions of Nh reactivity are discussed, along with results of the first experimental attempts to study Nh chemistry in the gas phase. The experimental observations verify a higher chemical reactivity of Nh atoms compared to its neighbor Fl and call for the development of advanced setups. First tests of a newly developed detection device miniCOMPACT with highly reactive Fr isotopes assure that effective chemical studies of Nh are within reach.
Ir Mssbauer spectroscopic parameters of Vaska's complexes and their oxidative adductsKaneko, Masashi; Nakashima, Satoru*
Inorganic Chemistry, 60(17), p.12740 - 12752, 2021/09
Times Cited Count：3 Percentile：32.49(Chemistry, Inorganic & Nuclear)In the present study, density functional theory (DFT) calculation was applied to Vaska's complexes of formula 
-[IrCl(CO)(PPh)], and their oxidative adducts with small molecules (YZ) including H, i.e., -[IrCl(YZ)(CO))(PPh)], to successfully correlate the electronic states of the complexes with the corresponding Ir Mssbauer spectroscopic parameters. After confirming the reproducibility of the DFT methods for elucidating the equilibrium structures and Ir Mssbauer isomer shifts of the octahedral Ir complexes, the isomer shifts and quadrupole splitting values of Vaska's complexes and their oxidative adducts were calculated. A bond critical point analysis revealed that the tendency in the isomer shifts was correlated with the strength of the covalent interaction in the coordination bonds. In an electric field gradient (EFG) analysis of the oxidative adducts, the sign of the principal axis was found to be positive for the complex with YZ = Cl and negative for the complex with YZ = H. This reversal of the sign of the EFG principal axis was caused by the difference in the electron density distribution for the coordination bonds between Ir and YZ, according to a density of states analysis.
Kagami, Saya; Yokoyama, Tatsunori; Umeda, Koji*
JAEA-Testing 2021-001, 49 Pages, 2021/08
JAEA-Testing-2021-001.pdf:3.86MB
To make a contribution to safety assessment for geological disposal of high level radioactive and/or TRU waste, we need to assess long-term stability of geological environment and predict long-term changes of geotectonic events that will occur in the future, especially for Quaternary period ( 2.6 million years ago-present). In the most case, we investigate chronological data of geological events by radiometric dating. When some geological samples have no objects to which radiometric dating method can be applied (e.g., zircon, biotite, wood fragments and plant residues), we can use tephrochronology, which is geological dating method using each layer of tephra (erupted volcanic ash), for dating of geological layers. This chronological method is essential in Japan, where volcanism is very active. Tephra is usually characterized by petrographic characteristics and/or chemical composition (mainly major elements) of volcanic glasses and/or minerals in tephra. In Tono Geoscience Center (Japan Atomic Energy Agency), we develop an analytical technique of chemical composition including trace elements of volcanic glasses for detailed tephra identification. In this paper, we report a sample preparation procedure and analytical methods of chemical compositions of individual volcanic glass shards by using an electron probe microanalyzer and a laser ablation-inductively coupled plasma-mass spectrometer.
Chiera, N. M.*; Sato, Tetsuya; Eichler, R.*; Tomitsuka, Tomohiro; Asai, Masato; Adachi, Sadia*; Dressler, R.*; Hirose, Kentaro; Inoue, Hiroki*; Ito, Yuta; et al.
Angewandte Chemie; International Edition, 60(33), p.17871 - 17874, 2021/08
Times Cited Count：2 Percentile：14.88(Chemistry, Multidisciplinary)The formation and the chemical characterization of single atoms of dubnium (Db, element 105), in the form of its volatile oxychloride, was investigated using the on-line gas phase chromatography technique, in the temperature range 350 - 600 
C. Under the exact same chemical conditions, comparative studies with the lighter homologs of group-5 in the Periodic Table clearly indicate the volatility sequence being NbOCl
TaOCl
DbOCl. From the obtained experimental results, thermochemical data for DbOCl were derived. The present study delivers reliable experimental information for theoretical calculations on the chemical properties of transactinides.
Iizuka, Riko*; Goto, Hirotada*; Shito, Chikara*; Fukuyama, Ko*; Mori, Yuichiro*; Hattori, Takanori; Sano, Asami; Funakoshi, Kenichi*; Kagi, Hiroyuki*
Scientific Reports (Internet), 11(1), p.12632_1 - 12632_10, 2021/06
Times Cited Count：3 Percentile：32.31(Multidisciplinary Sciences)The Earth's core consist of Fe-Ni alloy with some light elements (H, C, O, Si, S etc.). Hydrogen (H) is the most abundant element in the universe and one of the promising candidates. In this study, we have investigated the effects of sulfur(S) on hydrogenation of iron-hydrous silicate system containing saturated water in the ideal composition of the primitive Earth. We observed a series of phase transitions of Fe, dehydration of the hydrous mineral, and formation of olivine and enstatite with increasing temperature. The FeS formed as the coexisting phase of Fe under high-pressure and temperature condition, but its unit cell volume did not increase, suggesting that FeS is hardly hydrogenated. Recovered samples exhibited that H and S can be incorporated into solid Fe, which lowers the melting temperature as Fe(H
)-FeS system. No detection of other light elements (C, O, Si) in solid Fe suggests that they dissolve into molten iron hydride and/or FeS in the later process of Earth's core-mantle differentiation.
Gtz, M.*; Gtz, S.*; Kratz, J.-V.*; Ballof, J.*; Dllmann, Ch. E.*; Eberhardt, K.*; Mokry, C.*; Renisch, D.*; Runke, J.*; Sato, Tetsuya; et al.
Radiochimica Acta, 109(3), p.153 - 165, 2021/03
Times Cited Count：3 Percentile：45.99(Chemistry, Inorganic & Nuclear)We report on a novel two-chamber approach for the synthesis of volatile complexes that allows spatial decoupling of thermalization and gas-phase carbonyl complex synthesis. Neutron induced fission on 
U and spontaneous fission of 
Cm were employed for the production of the fission products. These were stopped inside a gas volume behind the target and flushed with an inert-gas flow into a second chamber. This was flushed with carbon monoxide to allow the gas-phase synthesis of carbonyl complexes. Parameter studies of the transfer from the first into the second chamber as well as on the carbonyl complex formation and transport processes have been performed. High overall efficiencies of more than 50% were reached rendering this approach interesting for studies of superheavy elements. Our results show that carbonyl complex formation of thermalized fission products is a single-atom reaction, and not a hot-atom reaction.
Matsumiya, Masahiko*; Nomizu, Daiki*; Tsuchida, Yusuke*; Sasaki, Yuji
Hydrometallurgy, 199, p.105539_1 - 105539_8, 2021/02
Times Cited Count：4 Percentile：33.99(Metallurgy & Metallurgical Engineering)The synergistic solvent extraction of lanthanide(III) with mixtures of di-(2-ethylhexyl)phosphoric acid (D2EHPA, A) and monoisodecyl phosphoric acid (MIDPA, B) in phosphonium-based ionic liquid was investigated. In the case of D2EHPA or MIDPA single extractant system, Ln(III) (Ln = Pr and Nd) was extracted as [LnAHA] or [LnBHB], respectively, the extracted species of Tb(III) or Dy(III) were determined by slope analysis. According to the equilibrium constants (
, 
and 
) and the formation constants (
, and 
), it was found that the extracted complex [TbHAB or [DyHAB] was more stable than [LnAHA] or [LnBHB]. The synergistic extraction effects were investigated to study the possibility of separating Dy(III) from Pr(III) and Nd(III) according to their separation factors.
Yamamoto, Masahiko; Do, V. K.; Taguchi, Shigeo; Kuno, Takehiko; Takamura, Yuzuru*
Journal of Radioanalytical and Nuclear Chemistry, 327(1), p.433 - 444, 2021/01
Times Cited Count：0 Percentile：0.01(Chemistry, Analytical)A simple, practical, and reliable analytical method for determination of Na, K, Ca, Sr, and Ba by liquid electrode plasma optical emission spectrometry is developed. Appropriate emission lines for quantification, interferences from co-existing elements, and effect of measurement conditions with cell damage have been investigated. The spike and recovery tests using actual sample have been performed for method validation, and negligible sample matrix effect has been observed. Consequently, the method is successfully applied to several radioactive wastes. The obtained data have been agreed well with data from computer calculation and inductively coupled plasma optical emission spectrometry within 10% difference.
