A Simple process simulation method for radiation stability evaluation of minor actinides separation

Toigawa, Tomohiro; Tsubata, Yasuhiro; Kumagai, Yuta; Ban, Yasutoshi

Progress in Nuclear Science and Technology (Internet), 8, p.286 - 290, 2025/09

https://doi.org/10.15669/pnst.8.286

We propose a simple process simulation methodology that uses readily available information about radiation impact. A process simulation was conducted for a minor actinides (MA) separation process while considering the degradation of extraction ability by radiolysis. The simulation provided a processing limit of MA and enabled the evaluation of radiation stability.

Separation of Am from lanthanides and Cm using the ADAAM(EH)-DTBA extraction system and elucidation of its complexation with DTBA through DFT calculations

Sasaki, Yuji; Kaneko, Masashi; Kumagai, Yuta; Ban, Yasutoshi

Solvent Extraction and Ion Exchange, 43(5-6), p.768 - 784, 2025/06

https://doi.org/10.1080/07366299.2025.2513982

We developed a method called the alkyl-diamide amine (ADAAM(EH))-diethylenetriamine-triacetic acid-bis(diethylacetamide) (DTBA) technique for separating actinide (An) and lanthanide (Ln) elements from high-level liquid waste. ADAAM(EH) exhibits a high separation factor (SF) not only for Am/Cm but also for light/heavy Ln under acidic conditions (1.5 M HNO). Consequently, Am can be separated from Cm as well as from middle Ln (Sm, Eu, and Gd) using ADAAM(EH) as an extractant. DTBA enables the stripping of Am and potentially separates it from Ln in the organic phase at low pH ( 2). The lowest SF among the light Ln, observed for Nd/Am, exceeded 10, indicating that Am can be separated from light Ln by stripping using DTBA from the ADAAM(EH) extraction solvent. The density functional theory calculations for understanding the coordination bond properties of metal-DTBA complexes are performed, which supported higher affinity of DTBA toward Am than Nd.

Improved extraction efficiency of radioactive copper produced via accelerator neutrons method through phosphate buffer-enhanced column pre-treatment

Mikhail, M. A. G.*; Kin, Tadahiro*; Eto, Taisei*; Tsukada, Kazuaki

Scientific Reports (Internet), 14, p.27132_1 - 27132_10, 2024/11

https://doi.org/10.1038/s41598-024-76660-y

We have studied a straightforward and robust single-step cation exchange separation method to isolate medical copper radioisotopes Cu and Cu produced in the Zn(n, x) reaction with an accelerator neutrons technique. This study revealed the key role of a phosphate buffer pre-treatment of the cation exchange column in the separation process. It was found that incorporating the phosphate buffer into the column pre-treatment markedly enhances the retention of copper isotopes within the column throughout the separation procedure. This approach yields a high-purity radioactive copper sample with a high extraction efficiency of 94.4% of the initially produced copper, all within a relatively short experimental time frame of approximately 5 h for 100 g of starting material.

Mutual separation of Am and Cm using ADAAM (alkyl DiAmide AMine) and reduction of volumes for liquid waste generated via batch-wise multistage extractions

Sasaki, Yuji; Kaneko, Masashi; Ban, Yasutoshi; Suzuki, Hideya*

Journal of Nuclear Science and Technology, 61(7), p.883 - 893, 2024/07

https://doi.org/10.1080/00223131.2023.2283214

The mutual separation of Am and Cm is conducted using an alkyl-diamide amine (ADAAM) extractant. ADAAM exhibits extremely high separation factor with respect to Am and Cm separation (5.9) in a nitric acid--dodecane system. The batch-wise multistage extractions are performed using a system containing 0.2 M ADAAM and 1.5 M nitric acid. In this multistage extraction, an organic solvent give 96.5% and 1.06% yields of Am and Cm. After the mutual separation of Am and Cm, an additional extraction step is included to reduce the volumes of these aqueous and organic phases. Taking these steps, Am and Cm can be recovered in just two or three stages in the aqueous phases.

Introduce of friction model into fuel pin bundle deformation analysis code "BAMBOO"

Uwaba, Tomoyuki; Ito, Masahiro*; Ishitani, Ikuo*

JAEA-Technology 2023-006, 36 Pages, 2023/05

JAEA-Technology-2023-006.pdf:3.45MB

The BAMBOO code developed by the Japan Atomic Energy Agency is a computer code to analyze fuel pin bundle deformation in a fast reactor wire-spaced type fuel pin bundle subassembly. In this study we developed an analysis model to consider friction at the contact points between adjacent fuel pins, and at these between outermost fuel pins and a duct that are due to bundle-duct interaction. This model deals with friction forces at contact points in the contact and separation analysis of the code, and employs a convergent calculation where contact forces are gradually determined to avoid numerical instability when the friction occurs. Analyses of BAMBOO with the model showed very slight effects on the onset of contact between outer most pins and a duct, and on directions of pin displacements, within the range of practical friction coefficients.

Americium(III)/curium(III) complete separation and sensitive fluorescence detection by capillary and gel electrophoresis using emissive hexadentate/octadentate polyaminocarboxylate ligands

Saito, Shingo*; Haraga, Tomoko; Marumo, Kazuki*; Sato, Yoshiyuki; Nakano, Yuta*; Tasaki-Handa, Yuiko*; Shibukawa, Masami*

Bulletin of the Chemical Society of Japan, 96(3), p.223 - 225, 2023/03

https://doi.org/10.1246/bcsj.20220346

Highly efficient and effective separation between americium (Am) and curium ion (Cm) was achieved by two simple electrophoresis-based techniques. Am and Cm ions were complexed with fluorophore-modified acyclic hexadentate and octadentate polyaminocarboxylates and then were electrophoretically separated and fluorescently detected in free solution with ternary complexation or in gel medium.

Analysis of the radioactivity concentrations in radioactive waste generated from JRR-3, JRR-4 and JRTF facilities

Tobita, Minoru*; Konda, Miki; Omori, Takeshi*; Nabatame, Tsutomu*; Onizawa, Takashi*; Kurosawa, Katsuaki*; Haraga, Tomoko; Aono, Ryuji; Mitsukai, Akina; Tsuchida, Daiki; et al.

JAEA-Data/Code 2022-007, 40 Pages, 2022/11

JAEA-Data-Code-2022-007.pdf:1.99MB

Radioactive wastes generated from nuclear research facilities in Japan Atomic Energy Agency are planning to be buried in the near surface disposal field. Therefore, it is required to establish the method to evaluate the radioactivity concentrations of radioactive wastes until the beginning of disposal. In order to contribute to this work, we collected and analyzed concrete, ash, ceramic and brick samples generated from JRR-3, JRR4 and JRTF facilities. In this report, we summarized the radioactivity concentrations of 24 radionuclides (H, C, Cl, Ca, Co, Ni, Sr, Nb, Tc, Ag, I, Cs, Ba, Eu, Eu, Ho, U, U, Pu, Pu, Pu, Am, Am, Cm) which were obtained from radiochemical analysis of the samples in fiscal years 2020-2021.

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JPDR, JRR-3 and JRR-4 Facilities

Tsuchida, Daiki; Mitsukai, Akina; Aono, Ryuji; Haraga, Tomoko; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2022-004, 87 Pages, 2022/07

JAEA-Data-Code-2022-004.pdf:6.73MB

Radioactive wastes generated from nuclear research facilities in Japan Atomic Energy Agency are planning to be buried in the near surface disposal field. Therefore, it is required to establish the method to evaluate the radioactivity concentrations of radioactive wastes until by the beginning of disposal. In order to contribute to this work, we collected and analyzed samples generated from JPDR, JRR-3 and JRR-4. In this report, radioactivity concentrations of 20 radionuclides (H, C, Cl, Co, Ni, Sr, Nb, Tc, Ag, I, Cs, Eu, Eu, U, U, Pu, Pu, Am, Cm) were determined based on radiochemical analysis and summarized as basic data for the study of evaluation method of radioactive concentration.

Upgrading of recovery method for radioactive microparticles by heavy liquid separation aiming to volume reduction of contaminated soil (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; University of Tsukuba*

JAEA-Review 2021-023, 49 Pages, 2021/12

JAEA-Review-2021-023.pdf:2.39MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Upgrading of recovery method for radioactive microparticles by heavy liquid separation aiming to volume reduction of contaminated soil" conducted from FY2018 to FY2020. Since the final year of this proposal was FY2020, the results for three fiscal years were summarized. The present study aims to develop a novel method to reduce the volume of contaminated soil caused by an accident at the Fukushima Daiichi Nuclear Power Station. The heavy liquid separation method, which was optimized in the previous year, was applied to nine soils collected in Fukushima Prefecture.

Design of microchannel suitable for packing with anion exchange resins; Uranium separation from seawater containing a large amount of cesium

Ouchi, Kazuki; Tsukahara, Takehiko*; Brandt, A.*; Muto, Yuki*; Nabatame, Nozomi*; Kitatsuji, Yoshihiro

Analytical Sciences, 37(12), p.1789 - 1794, 2021/12

https://doi.org/10.2116/analsci.21P110

We attempted to scale down a separation process of uranium (U) using the microchip column loaded with anion exchange resin to develop safety and waste-reducing separation technique. The ideal separation performance of U was obtained by the properly design of a microchannel. The concentration of U in seawater as a real-world sample could be quantified with the prepared microchip column. It indicates that the microchip column is sufficiently practical. Compared to separation of U with a general column, the column size was successfully scaled down to 1/5000.