Using X-ray absorption near edge structure to evaluate adsorption properties of rare earths and nitrogen by difference of their interactions

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

https://doi.org/10.1016/j.nimb.2024.165496

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.

Investigation of manganese(II) behavior in molten chlorides at precipitate formation by oxide addition

Yamamoto, Yuri*; Minowa, Kazuki*; Takahatake, Yoko; Watanabe, So; Nakamura, Masahiro; Matsuura, Haruaki*

Electrochemistry (Internet), 92(4), p.043019_1 - 043019_4, 2024/04

https://doi.org/10.5796/electrochemistry.23-69162

In the pyro-reprocessing of spent nuclear fuel, salt bath is normally used in several times, but at final moment, spent salt containing small amount of chloride nuclear fuel material is generated. In terms of managing nuclear fuel materials, it is desirable that the nuclear fuel materials should be recovered from the spent salt. We are proposing methods for recovering nuclear fuel materials using precipitation by oxide addition and distillation for reducing pressure techniques. In this study, we have focused on the behavior of manganese(II), which is one of the radioactivated products. As a result of experiments and thermodynamic simulation, it was found that manganese(II) is likely to be entrained in nuclear fuel materials. Therefore, it is necessary to add a step to separate manganese(II) from nuclear fuel materials.

Structural characterization of Eu-HONTA complexes by IBIL and EXAFS analyses

Watanabe, So; Sano, Yuichi; Okada, Makoto*; Matsuura, Haruaki*; Hagura, Naoto*; Kada, Wataru*

Nuclear Instruments and Methods in Physics Research B, 477, p.60 - 65, 2020/08

https://doi.org/10.1016/j.nimb.2019.10.004

IBIL and EXAFS analyses were applied on strucutral analysis of Eu complex formed in adsorbent developed for extraction chromatography. Those analyses revealed slight structural difference between adsorbent and solvent systems.

STRAD project for systematic treatments of radioactive liquid wastes generated in nuclear facilities

Watanabe, So; Ogi, Hiromichi*; Arai, Yoichi; Aihara, Haruka; Takahatake, Yoko; Shibata, Atsuhiro; Nomura, Kazunori; Kamiya, Yuichi*; Asanuma, Noriko*; Matsuura, Haruaki*; et al.

Progress in Nuclear Energy, 117, p.103090_1 - 103090_8, 2019/11

AA2019-0193.pdf:1.29MB

https://doi.org/10.1016/j.pnucene.2019.103090

Microanalysis of silica-based adsorbent for effective recovery of radioactive elements

Sano, Yuichi; Watanabe, So; Matsuura, Haruaki*; Nagoshi, Kohei*; Arai, Tsuyoshi*

Journal of Nuclear Science and Technology, 54(10), p.1058 - 1064, 2017/10

https://doi.org/10.1080/00223131.2017.1344574

For effective recovery of radioactive elements by adsorbents using polymer-immobilized silica (SiO-P) supports, the microstructure of SiO-P particles impregnated with CMPO as extractants and their change with the crosslinking degree of polymer (CDP) were investigated using STXM and EXAFS analyses; further, their relation with adsorption/elution behavior was discussed. The adsorption/elution tests using adsorbents with a different CDP demonstrated that a higher CDP inhibited the elution of adsorbed metal ions from the adsorbent. The results of STXM and EXAFS analyses suggested that adsorption by CMPO proceeds through the entire area in the adsorbent and the local structure around adsorbed metal ions is similar irrespective of the CDP. Conversely, STXM analyses implied the capture of eluents such as HO by polymers with high CDP, which suppresses the prompt elution of adsorbed metal ions from the adsorbent.

Microscopic analyses of complexes formed in adsorbent for Mo and Zr separation chromatography

Abe, Ryoji*; Nagoshi, Kohei*; Arai, Tsuyoshi*; Watanabe, So; Sano, Yuichi; Matsuura, Haruaki*; Takagi, Hideaki*; Shimizu, Nobutaka*; Koka, Masashi*; Sato, Takahiro*

Nuclear Instruments and Methods in Physics Research B, 404, p.173 - 178, 2017/08

https://doi.org/10.1016/j.nimb.2017.02.082

Structural investigation of thorium in molten lithium-calcium fluoride mixtures for salt treatment process in molten salt reactor

Numakura, Masahiko*; Sato, Nobuaki*; Bessada, C.*; Okamoto, Yoshihiro; Akatsuka, Hiroshi*; Nezu, Atsushi*; Shimohara, Yasuaki*; Tajima, Keisuke*; Kawano, Hirokazu*; Nakahagi, Takeshi*; et al.

Progress in Nuclear Energy, 53(7), p.994 - 998, 2011/11

https://doi.org/10.1016/j.pnucene.2011.04.026

X-ray absorption fine structure (XAFS) measurements on thorium fluoride in molten lithium-calcium fluoride mixtures and molecular dynamics (MD) simulation of zirconium and yttrium fluoride in molten lithium-calcium fluoride mixtures have been carried out. In the molten state, coordination number of thorium and inter ionic distances between thorium and fluorine in the first neighbor are nearly constant in all mixtures. However the fluctuation factors (Debye-Waller factor and C cumulant) increase until CaF = 0.17 and decrease by addition of excess CaF. It means that the local structure around Th is disordered until CaF=0.17 and stabilized over CaF = 0.17. The variation of fluctuation factors is related to the number density of F in ThF mixtures and the stability of local structure around Th increases with decreasing the number density of F in ThF mixtures. This tendency is common to those in the ZrF and YF mixtures.

Ion specific effects on the structure of molten AF-ZrF systems (A = Li, Na, and K)

Pauvert, O.*; Salanne, M.*; Zanghi, D.*; Simon, C.*; Reguer, S.*; Thiaudire, D.*; Okamoto, Yoshihiro; Matsuura, Haruaki*; Bessada, C.*

Journal of Physical Chemistry B, 115(29), p.9160 - 9167, 2011/07

https://doi.org/10.1021/jp203137h

The structure of molten AF-ZrF system (A=Li, Na, K) is studied using EXAFS spectroscopy with molecular dynamics simulations. From the Zr solvation shell point of view, we observe a progressive stabilization of the 7-fold and then of the 6-fold coordinated complexes when passing from Li to Na and K as a "counterion". Particular attention is given to the systems consisting of 35 mol% of ZrF. At that particular composition, the ZrF complex predominates largely whatever the nature of the alkali. The calculated vibrational properties of this complex are in excellent agreement with a previous Raman spectroscopy experiment on molten KF-ZrF. The most important differences are observed for the lifetime of these octahedral units. On a larger scale, an intense first sharp diffraction peak is observed for the Zr-Zr partial structure factor, which can be attributed to the correlations between the octahedral units formed.

X-ray structural analysis of molten PbCl

Okamoto, Yoshihiro; Iwadate, Yasuhiko*; Fukushima, Kazuko*; Matsuura, Haruaki*; Minato, Kazuo

Journal of Physics and Chemistry of Solids, 66(2-4), p.452 - 455, 2005/02

https://doi.org/10.1016/j.jpcs.2004.06.039

The structure of molten PbCl was investigated by using X-ray diffrtaction(XRD) and X-ray absorption fine structure(XAFS) analysis techniques. From the fourier transformation analysis if the XRD data, the nearest Pb-Cl interaction consists of two kinds of interactions; rigid 4-fold tetrahedron and 2-3 loose coordination. The XAFS result shows a local structure is the 4-fold coordination in the melt.

Development of the evaluation method for the aerosol deposition amounts in the containment vessel and the reactor building, 1; Effect of surface materials on the aerosol deposition behavior

Miyahara, Naoya; Suzuki, Eriko; Uesawa, Shinichiro; Sato, Isamu*; Matsuura, Haruaki*; Hagura, Naoto*; Koshigoe, Koki*; Osaka, Masahiko

no journal, , 

We have started the fundamental research on detailed aerosol deposition phenomena at the walls of containment vessel and reactor building to develop a reasonable evaluation model of aerosol deposition amount which have a large influence on release amount to the environment. In this study, an aerosol deposition test onto various materials was conducted to investigate the physical and chemical phenomena related to aerosol deposition. As a result, important phenomena such as aerosol penetration into concrete pore were observed, which should be considered in the aerosol deposition model.