Subcritical water treatment of spent tannin-based uranium recovery adsorbent

Iwamoto, Toshihiro; Omori, Kohei; Arai, Yoichi; Funakoshi, Tomomasa; Watanabe, So; Nakamura, Masahiro; Watanabe, Masaru*

Proceedings of 32nd International Conference on Nuclear Engineering, Vol.13 (Internet), p.525 - 533, 2026/01

https://doi.org/10.1007/978-981-95-3409-8_44

Weathering promotes the sorption of radiocesium in mafic minerals of river sediments in the Fukushima Prefecture, Japan

Hagiwara, Hiroki; Watanabe, Yusuke; Konishi, Hiromi*; Funaki, Hironori; Fujiwara, Kenso; Iijima, Kazuki

Applied Geochemistry, 190, p.106490_1 - 106490_10, 2025/10

https://doi.org/10.1016/j.apgeochem.2025.106490

Development of fluorinated ligands for uranium recovery from radioactive liquid waste

Arai, Yoichi; Goto, Yasuhiro; Watanabe, So; Agou, Tomohiro*; Arai, Tsuyoshi*; Katsuki, Kenta*; Fukumoto, Hiroki*; Hoshina, Hiroyuki*; Seko, Noriaki*

Progress in Nuclear Science and Technology (Internet), 8, p.329 - 332, 2025/09

https://doi.org/10.15669/pnst.8.329

A Basic study for radioactive nuclides recovery from spent PUREX solvent using adsorbents

Arai, Tsuyoshi*; Nakamura, Fumiya*; Abe, Ryoji*; Ueno, Fuga*; Seko, Noriaki*; Arai, Yoichi; Watanabe, So

Progress in Nuclear Science and Technology (Internet), 7, p.147 - 153, 2025/03

https://doi.org/10.15669/pnst.7.147

no abstracts in English

New filter concept for removal of fine particle generated in high level radioactive solution

Takahatake, Yoko; Watanabe, So; Watanabe, Masayuki; Sano, Yuichi; Takeuchi, Masayuki

Progress in Nuclear Science and Technology (Internet), 7, p.195 - 198, 2025/03

https://doi.org/10.15669/pnst.7.195

Extraction chromatgraphy technology for trivalent minor actinide (MA(III) ; Am(III) and Cm(III)) recovery from the solution generated by an extraction process in reprocessing of spent nuclear fuel has been developed. A fine particle is generated in the solution. The fine particle must be removed before MA recovery operation, because that leads clogging of the extraction chlomatography column. In order to prevent clogging the column, filtration system utilizing porous silica beads packed column has been designed. In this study, a fine particle trapping system was developed and particle removal performance of the system was experimentally evaluated using alumina particles as simulated fine particle. Column experiments revealed that the fine particle with the particle size from 0.12 to 15 m is cause of clogging of the filtration column. Since simulated fine particles were trapped on filtration experiments, a filtration system using the porous silica beads column is practical,

Development of Ra collection technology for production of medical tracer Ac

Oguri, Kaori; Watanabe, So; Arai, Yoichi; Shirasaki, Kenji*; Nakase, Masahiko*

Research Activity of RDG Collaboration Research in 2023, Institute for Materials Research, Tohoku University (Internet), p.D14 - D17, 2025/02

Actinium-225 (Ac) is focused from the viewpoint of cancer therapy using alpha particles. Ac can be produced with gamma-ray via Ra(gamma,n)Ra-Ac reaction. Since a radium (Ra) source must be secured to promote this production pathway, we set out to develop a Ra recovery technology. Ra, owing to the radioactive decay of primordial U, U, and Th, is a radioactive element commonly found within soils, sediments, and natural waters. Therefore, we have focused on extracting Ra from those things to build an effective process to create the Ra target. In this study, we performed sorption studies with Barium (Ba), homologs element of Ra, which may coexist with Ra in soil. The study of recovery methods for adsorbed elements, such as elution, requires clarification of the adsorption reaction mechanism as well as investigation of adsorption behavior. In order to elucidate local structure around Ba(II) loaded in the metal (hydr)oxides and certain clay minerals, Extended X-ray Absorption Fine Structure (EXAFS) analysis was also carried out. The results of these tests confirmed that Ba and Ra exhibit similar adsorption behavior for clay materials, and that Ba and Ra have the potential to form endospheric complexes for Mn oxides.

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.

Start-up of a test equipment for corrosion evaluation using copper thin film

Suganuma, Kazuaki; Sekiyama, Yoshio*; Honda, Tomoyuki*; Dei, Tatsumi; Suzuki, Katsuo; Fujirai, Kosuke; Suzuki, Hiroshi*; Nakata, Morihiro*; Hosokawa, Hideaki*; Watanabe, Yasuhiro; et al.

Proceedings of 21st Annual Meeting of Particle Accelerator Society of Japan (Internet), p.738 - 740, 2024/10

https://www.pasj.jp/web_publish/pasj2024/proceedings/PDF/THP0/THP061.pdf

In the J-PARC accelerator, the inner surface of the copper tubes that make up most of the coolant pipes is corroded. Generally, additives are added to the coolant to prevent corrosion, but the accelerator is in a radiation environment and additives cannot be used in the coolant to avoid impurities in the coolant become polluted by radiation. For example, in materials research in the nuclear field, there is a lot of research on strong acidic or strong alkaline solutions and corrosion resistant materials, but there is little literature on corrosion protection studies of purified water and copper materials. In general, we believe this is because the use of purified water and copper together in a radiation environment is limited. Corrosion testing of purified water and copper materials is unique to accelerators. The use of a thin copper film was considered as a possible method. In this case, we report on the current status of a new initiative, testing with copper thin films.

Introduction to dismantling and decommissioning chemistry

Sato, Nobuaki*; Kameo, Yutaka; Sato, Soichi; Kumagai, Yuta; Sato, Tomonori; Yamamoto, Masahiro*; Watanabe, Yutaka*; Nagai, Takayuki; Niibori, Yuichi*; Watanabe, Masayuki; et al.

Introduction to Dismantling and Decommissioning Chemistry, 251 Pages, 2024/09

This book focuses on the dismantling and decommissioning of nuclear facilities and reactors that have suffered severe accidents. In Part 1, we introduce basic aspects ranging from fuel chemistry, analytical chemistry, radiation chemistry, corrosion, and decontamination chemistry to waste treatment and disposal. Then, Part 2 covers the chemistry involved in the decommissioning of various nuclear facilities, and discusses what chemical approaches are necessary and possible for the decommissioning of TEPCO's Fukushima Daiichi Nuclear Power Plants, how decommissioning should be carried out, and what kind of research and development and also human resource development are required for this.

Ion beam induced luminescence of lanthanide complexes in organic solvents irradiated by hydrogen and argon ion beams

Nakahara, Masaumi; Watanabe, So; Ishii, Yasuyuki*; Yamagata, Ryohei*; Yuri, Yosuke*; Yuyama, Takahiro*; Ishizaka, Tomohisa*; Koka, Masashi*; Yamada, Naoto*; Hagura, Naoto*

Nuclear Instruments and Methods in Physics Research B, 554, p.165449_1 - 165449_5, 2024/09

https://doi.org/10.1016/j.nimb.2024.165449

Ion beam induced luminescence analysis of lanthanide complexes in the organic solvents for minor actinides recovery process was carried out to investigate the structures of complexes. In this study, hydrogen ion beam obtained from the single-ended accelerator and argon ion beam obtained from the azimuthally varying field cyclotron were used in Takasaki Ion Accelerators for Advanced Radiation Application in National Institutes for Quantum Science and Technology. In the experiments, ion beam induced luminescence spectra of lanthanide complexes in the organic solvents were measured, and the relationship between the obtained spectra and the structures of complexes was studied.