Achievements and status of the STRAD project for radioactive liquid waste management

Arai, Yoichi; Watanabe, So; Nakahara, Masaumi; Funakoshi, Tomomasa; Hoshino, Takanori; Takahatake, Yoko; Sakamoto, Atsushi; Aihara, Haruka; Hasegawa, Kenta; Yoshida, Toshiki; et al.

Progress in Nuclear Science and Technology (Internet), 7, p.168 - 174, 2025/05

https://doi.org/10.15669/pnst.7.168

The Japan Atomic Energy Agency (JAEA) has been conducting a project named "Systematic Treatment of RAdioactive liquid waste for Decommissioning (STRAD)" project since 2018 for fundamental and practical studies for treating radioactive liquid wastes with complicated compositions. Fundamental studies have been conducted using genuine liquid wastes accumulated in a hot laboratory of the JAEA called the Chemical Processing Facility (CPF), and treatment procedures for all liquid wastes in CPF were successfully designed on the results obtained. As the next phase of the project, new fundamental and practical studies on primarily organic liquid wastes accumulated in different facilities of JAEA are in progress. This paper reviews the representative achievements of the STRAD project and introduces an overview of ongoing studies.

Investigation of adsorption mechanism of Mo(VI) by baker's yeast and applicability to the uranium liquid waste treatment process

Arai, Yoichi; Hasegawa, Kenta; Watanabe, So; Watanabe, Masayuki; Minowa, Kazuki*; Matsuura, Haruaki*; Hagura, Naoto*; Katsuki, Kenta*; Arai, Tsuyoshi*; Konishi, Yasuhiro*

Journal of Radioanalytical and Nuclear Chemistry, 333(7), p.3585 - 3593, 2024/07

https://doi.org/10.1007/s10967-023-09278-5

Kinetic analysis of mass transfer of Eu(III) in extractant-impregnated polymer-layered silica particle in multiple-ion distribution system

Miyagawa, Akihisa*; Hayashi, Naoki*; Iwamoto, Hibiki*; Arai, Tsuyoshi*; Nagatomo, Shigenori*; Miyazaki, Yasunori; Hasegawa, Kenta; Sano, Yuichi; Nakatani, Kiyoharu*

Analytical Sciences, 40(2), p.347 - 352, 2024/02

https://doi.org/10.1007/s44211-023-00462-x

The Eu(III) distribution mechanism in single extractant-impregnated polymer-layered silica particle in a complex solution containing multiple lanthanide ions was investigated using fluorescence microspectroscopy. The rate-determining step was the reaction of Eu(III) with the two extractant molecules. The obtained mechanism and rate constants agreed with those of the single-ion distribution system, in which Eu(III) was distributed to the particles in the Eu(III) solution.

Evaluation of the remaining spent extraction solvent in vermiculite after leaching tests via PIXE analysis

Arai, Yoichi; Watanabe, So; Hasegawa, Kenta; Okamura, Nobuo; Watanabe, Masayuki; Takeda, Keisuke*; Fukumoto, Hiroki*; Ago, Tomohiro*; Hagura, Naoto*; Tsukahara, Takehiko*

Nuclear Instruments and Methods in Physics Research B, 542, p.206 - 213, 2023/09

https://doi.org/10.1016/j.nimb.2023.07.003

Multipole polaron in the devil's staircase of CeSb

Arai, Yosuke*; Kuroda, Kenta*; Nomoto, Takuya*; Tin, Z. H.*; Sakuragi, Shunsuke*; Bareille, C.*; Akebi, Shuntaro*; Kurokawa, Kifu*; Kinoshita, Yuto*; Zhang, W.-L.*; et al.

Nature Materials, 21(4), p.410 - 415, 2022/04

https://doi.org/10.1038/s41563-021-01188-9

Devil's staircase transition of the electronic structures in CeSb

Kuroda, Kenta*; Arai, Yosuke*; Rezaei, N.*; Kunisada, So*; Sakuragi, Shunsuke*; Alaei, M.*; Kinoshita, Yuto*; Bareille, C.*; Noguchi, Ryo*; Nakayama, Mitsuhiro*; et al.

Nature Communications (Internet), 11, p.2888_1 - 2888_9, 2020/06

https://doi.org/10.1038/s41467-020-16707-6

Design and performance of high-pressure PLANET beamline at pulsed neutron source at J-PARC

Hattori, Takanori; Sano, Asami; Arima, Hiroshi*; Komatsu, Kazuki*; Yamada, Akihiro*; Inamura, Yasuhiro; Nakatani, Takeshi; Seto, Yusuke*; Nagai, Takaya*; Utsumi, Wataru; et al.

Nuclear Instruments and Methods in Physics Research A, 780, p.55 - 67, 2015/04

https://doi.org/10.1016/j.nima.2015.01.059

PLANET is a time-of-flight (ToF) neutron beamline dedicated to high-pressure and high-temperature experiments. The large six-axis multi-anvil high-pressure press designed for ToF neutron diffraction experiments enables routine data collection at high pressures and high temperatures up to 10 GPa and 2000 K, respectively. To obtain clean data, the beamline is equipped with the incident slits and receiving collimators to eliminate parasitic scattering from the high-pressure cell assembly. The high performance of the diffractometer for the resolution ( / 0.6%) and the accessible -spacing range (0.2-8.4 ) together with low-parasitic scattering characteristics enables precise structure determination of crystals and liquids under high pressure and temperature conditions.

Mode-distribution analysis of quasielastic neutron scattering and application to liquid water

Kikuchi, Tatsuya; Nakajima, Kenji; Kawamura, Seiko; Inamura, Yasuhiro; Yamamuro, Osamu*; Kofu, Maiko*; Kawakita, Yukinobu; Suzuya, Kentaro; Nakamura, Mitsutaka; Arai, Masatoshi

Physical Review E, 87(6), p.062314_1 - 062314_8, 2013/06

https://doi.org/10.1103/PhysRevE.87.062314

A quasi-elastic neutron scattering (QENS) experiment is a particular technique that endeavors to define a relationship between time and space for the diffusion dynamics of atoms and molecules. However, in most cases, analyses of QENS data are model dependent. We have developed a new method for processing QENS data without a specific model, wherein all modes can be described as combinations of the relaxations based on the exponential law. By this method, we can obtain a new distribution function, , which we call the mode distribution function (MDF), to represent the number of relaxation modes and distributions of the relaxation times in the modes. The deduction of MDF is based on the maximum entropy method. We report the first application to experimental data of liquid water. In addition to the two known modes, the existence of a new relaxation mode of water molecules with an intermediate time scale has been discovered.

Current status of a new polarized neutron reflectometer at the intense pulsed neutron source of the Materials and Life Science Experimental Facility (MLF) of J-PARC

Takeda, Masayasu; Yamazaki, Dai; Soyama, Kazuhiko; Maruyama, Ryuji; Hayashida, Hirotoshi; Asaoka, Hidehito; Yamazaki, Tatsuya; Kubota, Masato; Aizawa, Kazuya; Arai, Masatoshi; et al.

Chinese Journal of Physics, 50(2), p.161 - 170, 2012/04

http://psroc.org/cjp/issues.php?vol=50&num=2

Research on glass cells for He neutron spin filters

Sakaguchi, Yoshifumi; Kira, Hiroshi; Oku, Takayuki; Shinohara, Takenao; Suzuki, Junichi; Sakai, Kenji; Nakamura, Mitsutaka; Suzuya, Kentaro; Aizawa, Kazuya; Arai, Masatoshi; et al.

Physica B; Condensed Matter, 406(12), p.2443 - 2447, 2011/06

https://doi.org/10.1016/j.physb.2010.12.020