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.

Microbiome analysis of the restricted bacteria in radioactive element-containing water at the Fukushima Daiichi Nuclear Power Station

Warashina, Tomoro*; Sato, Asako*; Hinai, Hiroshi; Shaikhutdinov, N.*; Shagimardanova, E.*; Mori, Hiroshi*; Tamaki, Satoshi*; Saito, Motofumi*; Sanada, Yukihisa; Sasaki, Yoshito; et al.

Applied and Environmental Microbiology, 90(4), p.e02113-23_1 - e02113-23_23, 2024/04

https://doi.org/10.1128/aem.02113-23

Influence of plutonium content in dissolver solutions derived from irradiated fast reactor fuels on plutonium stripping in multistage countercurrent liquid-liquid extraction with acid split flowsheet

Nakahara, Masaumi; Shibata, Atsuhiro

Journal of Nuclear Science and Technology, 60(7), p.849 - 858, 2023/07

https://doi.org/10.1080/00223131.2022.2162137

To develop the acid split method which has highly nuclear proliferation resistance, influence of Pu content in dissolver solutions derived from irradiated fast reactor fuel on the Pu stripping was investigated in experiments and a calculation. The Pu content in the U/Pu and U products increased with increasing the Pu content in the dissolver solution. Moreover, the calculated results indicate that the Pu leakage into the U product is suppressed with the Pu stripping solution only at low temperature.

Harmless treatment of radioactive liquid wastes for safe storage in systematic treatment of radioactive liquid waste for decommissioning project

Nakahara, Masaumi; Watanabe, So; Aihara, Haruka; Takahatake, Yoko; Arai, Yoichi; Ogi, Hiromichi*; Nakamura, Masahiro; Shibata, Atsuhiro; Nomura, Kazunori

Proceedings of International Conference on Nuclear Fuel Cycle; Sustainable Energy Beyond the Pandemic (GLOBAL 2022) (Internet), 4 Pages, 2022/07

Various radioactive wastes have been generated from Chemical Processing Facility for basic research on advanced reactor fuel reprocessing, radioactive waste disposal, and nuclear fuel cycle technology. Many types of reagents have been used for the experiments, and some troublesome materials were produced in the course of experiments. The radioactive liquid wastes were treated for stable and safe storage using decomposition, solvent extraction, precipitation, and solidification methods. In this study, current status of harmless treatment for the radioactive liquid wastes would be reported.

Stabilization treatment of nuclear fuel material contained with organic matter

Senzaki, Tatsuya; Arai, Yoichi; Yano, Kimihiko; Sato, Daisuke; Tada, Kohei; Ogi, Hiromichi*; Kawanobe, Takayuki*; Ono, Shimpei; Nakamura, Masahiro; Kitawaki, Shinichi; et al.

JAEA-Testing 2022-001, 28 Pages, 2022/05

JAEA-Testing-2022-001.pdf:2.33MB

In preparation for the decommissioning of Laboratory B of the Nuclear Fuel Cycle Engineering Laboratory, the nuclear fuel material that had been stored in the glove box for a long time was moved to the Chemical Processing Facility (CPF). This nuclear fuel material was stored with sealed by a polyvinyl chloride (PVC) bag in the storage. Since it was confirmed that the PVC bag swelled during storage, it seems that any gas was generated by radiolysis of the some components contained in the nuclear fuel material. In order to avoid breakage of the PVC bag and keep it safety for long time, we began the study on the stabilization treatment of the nuclear fuel material. First, in order to clarify the properties of nuclear fuel material, radioactivity analysis, component analysis, and thermal analysis were carried out. From the results of thermal analysis, the existence of organic matter was clarified. Then, ion exchange resin with similar thermal characteristics was selected and the thermal decomposition conditions were investigated. From the results of these analyzes and examinations, the conditions for thermal decomposition of the nuclear fuel material contained with organic matter was established. Performing a heat treatment of a small amount of nuclear fuel material in order to confirm the safety, after which the treatment amount was scaled up. It was confirmed by the weight change after the heat treatment that the nuclear fuel material contained with organic matter was completely decomposed.

Development of MA separation process with TEHDGA/SiO-P for an advanced reprocessing

Horiuchi, Yusuke; Watanabe, So; Sano, Yuichi; Takeuchi, Masayuki; Kida, Fukuka*; Arai, Tsuyoshi*

Journal of Radioanalytical and Nuclear Chemistry, 330(1), p.237 - 244, 2021/10

AA2021-0174.pdf:1.7MB

https://doi.org/10.1007/s10967-021-07940-4

Applicability of tetra2-ehylhexyl diglycolamide (TEHDGA) impregnated adsorbent for minor actinide (MA) recovery from high level liquid waste (HLLW) in extraction chromatography technology was investigated through batch-wise adsorption and column separation experiments. Distribution ratio of representative fission product elements were obtained by the batch-wise experiments, and TEHDGA adsorbent was shown to be preferable to TODGA adsorbent for decontamination of several species. All Ln(III) supplied into the TEHDGA adsorbent packed column was properly eluted from the column, and the applicability of the adsorbent was successfully showed by this study.

Oxidative decomposition of ammonium ion with ozone in the presence of cobalt and chloride ions for the treatment of radioactive liquid waste

Aihara, Haruka; Watanabe, So; Shibata, Atsuhiro; Mahardiani, L.*; Otomo, Ryoichi*; Kamiya, Yuichi*

Progress in Nuclear Energy, 139, p.103872_1 - 103872_9, 2021/09

AA2020-0412.pdf:1.22MB

https://doi.org/10.1016/j.pnucene.2021.103872

A Project focusing on the contamination mechanism of concrete after the accident at Fukushima Daiichi Nuclear Power Plant

Yamada, Kazuo*; Maruyama, Ippei*; Haga, Kazuko*; Igarashi, Go*; Aihara, Haruka; Tomita, Sayuri*; Kiran, R.*; Osawa, Norihisa*; Shibata, Atsuhiro; Shibuya, Kazutoshi*; et al.

Proceedings of International Waste Management Symposia 2021 (WM2021) (CD-ROM), 10 Pages, 2021/03

Microscopic analyses on Zr adsorbed IDA chelating resin by PIXE and EXAFS

Arai, Yoichi; Watanabe, So; Ono, Shimpei; Nomura, Kazunori; Nakamura, Fumiya*; Arai, Tsuyoshi*; Seko, Noriaki*; Hoshina, Hiroyuki*; Hagura, Naoto*; Kubota, Toshio*

Nuclear Instruments and Methods in Physics Research B, 477, p.54 - 59, 2020/08

https://doi.org/10.1016/j.nimb.2019.10.028

Improvement in flow-sheet of extraction chromatography for trivalent minor actinides recovery

Watanabe, So; Senzaki, Tatsuya; Shibata, Atsuhiro; Nomura, Kazunori; Takeuchi, Masayuki; Nakatani, Kiyoharu*; Matsuura, Haruaki*; Horiuchi, Yusuke*; Arai, Tsuyoshi*

Journal of Radioanalytical and Nuclear Chemistry, 322(3), p.1273 - 1277, 2019/12

https://doi.org/10.1007/s10967-019-06808-y