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Journal Articles

Performance comparison of monoamides on U recovery by temperature swing extraction using Ce

Iwamoto, Toshihiro; Saito, Madoka*; Takahatake, Yoko; Watanabe, So; Watanabe, Masayuki; Naruse, Atsuki*; Tsukahara, Takehiko*

Mechanical Engineering Journal (Internet), 11(2), p.23-00444_1 - 23-00444_7, 2024/04

Journal Articles

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

 Times Cited Count:1 Percentile:41.04(Instruments & Instrumentation)

Journal Articles

Treatment of U contaminated waste generated from nuclear fuel fabrication process, 1; Ce(IV) recovery by temperature swing extraction with monoamides

Iwamoto, Toshihiro; Saito, Madoka*; Takahatake, Yoko; Watanabe, So; Watanabe, Masayuki; Naruse, Atsuki*; Tsukahara, Takehiko*

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 4 Pages, 2023/05

Applicability of temperature swing extraction technology employing monoamides was examined for uranium contaminated waste treatment procedure. Separation experiments on simulated target solution with three kinds of monoamides with different structure showed that Ce(IV) in the solution was selectively recovered by the temperature swing extraction operation. Based on the experiments, an appropriate monoamide for the procedure was selected.

Journal Articles

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

 Times Cited Count:1 Percentile:4.87(Chemistry, Analytical)

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.

Journal Articles

Determination of $$^{135}$$Cs/$$^{137}$$Cs isotopic ratio in soil collected near Fukushima Daiichi Nuclear Power Station through mass spectrometry

Shimada, Asako; Tsukahara, Takehiko*; Nomura, Masao*; Kim, M. S.*; Shimada, Taro; Takeda, Seiji; Yamaguchi, Tetsuji

Journal of Nuclear Science and Technology, 58(11), p.1184 - 1194, 2021/11

 Times Cited Count:6 Percentile:63.12(Nuclear Science & Technology)

Determining the completeness of nuclear reactor decommissioning is an important step in safely utilizing nuclear power. For example, $$^{137}$$Cs from the Fukushima Daiichi Nuclear Power Station (FDNPS) accident can be treated as background radioactivity, so determining the origin of $$^{137}$$Cs is essential. To accomplish this, measuring the $$^{135}$$Cs/$$^{137}$$Cs isotope ratio can be useful, so this study optimized a solvent extraction method, with calix[4]arene-bis(t-octylbenzo-crown-6) [BOBCalixC6] in 1-octanol, to purify radioactive Cs, radiocesium, from a solution of major environmental soil elements and mass spectrometry interference elements. This optimized method was applied to Cs purification in soil samples (40 g), and the final solutions contained a total of 10$$mu$$g/ml of the major soil elements and ng/ml concentrations at most of interfering elements. Soil samples collected near the FDNPS were then purified, and the $$^{135}$$Cs/$$^{137}$$Cs isotope ratios were measured, using both thermal ionization mass spectrometry (TIMS) and triple quadrupole induced coupled plasma mass spectrometry (ICP-QQQ). The results of each of these measurements were compared, and we found that Cs isotope ratios obtained by TIMS were more precise, by an order of magnitude, while the ICP-QQQ results possessed good abundance sensitivities. A slightly higher $$^{135}$$Cs/$$^{137}$$Cs ratio in the northwest area of the FDNPS was observed, while other areas exhibited similar values, all within the measurement error range, which indicated different origins of radiocesium. These results agreed with previously reported $$^{134}$$Cs/$$^{137}$$Cs activity distributions, suggesting that this ratio may be useful in identifying radiocesium origins for evaluating future nuclear reactor decommissions.

Journal Articles

No secondary waste recycle technology for rare metals using the hydrophilic extraction with phase transfer phenomena

Tsukahara, Takehiko*; Saga, Kaname*; Suzuki, Hideya*; Matsumura, Tatsuro

Kurin Tekunoroji, 29(12), p.4 - 7, 2019/12

no abstracts in English

Journal Articles

Direct temperature-swing extraction of rare-earth elements from acidic solution using the hydrophobic interactions of poly($$N$$-isopropylacrylamide) with diglycolamide-typed ligands

Saga, Kaname*; Suzuki, Hideya; Matsumura, Tatsuro; Tsukahara, Takehiko*

Analytical Sciences, 35(4), p.461 - 464, 2019/04

 Times Cited Count:4 Percentile:15.19(Chemistry, Analytical)

The phase transition-based gelification phenomenon of poly-$$N$$-isopropylacrylamide (PNIPAAm) in aqueous solutions has a great potential in developing new waste-free extraction processes of metal ions. By using hydrophobic diglycolamide-typed ligands in gelification extraction, a one-step complete extraction of all the RE ions from a nitric acid solution was successfully realized.

Journal Articles

Separation and recovery of raremetals using the hydrophiric extraction with phase transfer phenomena

Tsukahara, Takehiko*; Suzuki, Hideya*; Matsumura, Tatsuro; Saga, Kaname*

Bunri Gijutsu, 49(4), p.221 - 225, 2019/04

no abstracts in English

Oral presentation

Development of temperature swing extraction apparatus for uranium waste treatment

Kai, Masao; Sato, Takanori*; Iwamoto, Toshihiro; Saito, Madoka*; Nakahara, Masaumi; Takahatake, Yoko; Watanabe, So; Nakamura, Masahiro; Naruse, Atsuki*; Itoda, Naokazu*; et al.

no journal, , 

The sludges containing uranium are generated in the nuclear fuel fabrication facilities. Uranium is planned to be selectively recovered from the sludge leachate. The temperature swing extraction method was selected for the selective recovery of uranium. In this study, a small-scale testing system was developed, and the performances of the agitation, the transportation of the gel-containing solution, and the separation of the gel were experimentally examined. Cerium(IV) was used instead of uranium, and agitator blades were selected to agitate the gel solution effectively. The gel solution was transferred through the self-feeding pump and was successfully separated into the gel and the solution using the spin dryer with a filter cloth.

Oral presentation

Local distribution and isotopic ratio of radiocesium in environment

Shimada, Asako; Tsukahara, Takehiko*; Nomura, Masao*; Takeda, Seiji

no journal, , 

Because of the accident at the Fukushima Daiichi Nuclear Power Station (1F), a large area of eastern Japan was contaminated by radiocesium. When radiocesium would be detected at the completion of their decommissioning in the site, estimation of the origin of which is from background originated 1F and fallout of atmospheric nuclear test or from decommissioned facilities will be important. Therefore, soils of 3 sites were collected by using U8 containers, and $$^{137}$$Cs radioactivity, $$^{134}$$Cs/$$^{137}$$Cs radioactivity ratios, $$^{135}$$Cs/$$^{137}$$Cs isotope ratios were determined. $$^{137}$$Cs radioactivity concentrations were varied in not only between sites but also in the same site, however, $$^{134}$$Cs/$$^{137}$$Cs radioactivity ratio was approximately constant in all sites. In case of highly contaminated soils, $$^{135}$$Cs/$$^{137}$$Cs isotope ratio was almost comparable to that for the soil collected at near the 1F. On the other hand, in case of lower contaminated soils, $$^{135}$$Cs/$$^{137}$$Cs isotope ratio was slightly higher than that for soil collected at near the 1F. It is possibly that fallout before the 1F accident contained $$^{135}$$Cs to increase the $$^{135}$$Cs/$$^{137}$$Cs isotope ratio.

Oral presentation

First measurement of $$^{135}$$Cs/$$^{137}$$Cs isotope ratio in Japanese soil before the accident at the Fukushima Daiichi Nuclear Power Station

Shimada, Asako; Xu, J.*; Tsukahara, Takehiko*; Nomura, Masao*; Takeda, Seiji; Takahashi, Hiroaki*

no journal, , 

Cesium-137 concentration in environmental soil samples near and inside Tokai-mura was exceeded site release standard, 0.1 Bq/g, because of the accident at the Fukushima Daiichi Nuclear Power Station (1F). It is possibly to use the $$^{135}$$Cs/$$^{137}$$Cs isotope ratio to distinguish the $$^{137}$$Cs from the 1F and from decommissioned facility. However, radiocesium from global fallout is also contained in soil and it may be influenced on the $$^{135}$$Cs/$$^{137}$$Cs isotope ratio. There are no data of $$^{135}$$Cs/$$^{137}$$Cs isotope ratio before the 1F accident for soil samples collected in Japan. Therefore, $$^{135}$$Cs/$$^{137}$$Cs isotope ratio in soil samples collected in 2008 y at Tokai-mura was measured to be 2.61$$pm$$0.28 agreed with the result for sampled collected in USA.

Oral presentation

$$^{135}$$Cs/$$^{137}$$Cs isotope ratio near the Fukushima Daiichi Nuclear Power Station

Shimada, Asako; Tsukahara, Takehiko*; Nomura, Masao*; Shimada, Taro; Takeda, Seiji

no journal, , 

no abstracts in English

Oral presentation

Development of analytical method of $$^{135}$$Cs/$$^{137}$$Cs isotope ratio in environmental soil samples

Shimada, Asako; Kim, M. S.*; Tsukahara, Takehiko*; Nomura, Masao*; Shimada, Taro; Takeda, Seiji; Yamaguchi, Tetsuji

no journal, , 

no abstracts in English

Oral presentation

Development of chemical separation method for the measurement of $$^{135}$$Cs/$$^{137}$$Cs isotopic ratio in environmental samples

Shimada, Asako; Nomura, Masao*; Tsukahara, Takehiko*; Takeda, Seiji

no journal, , 

Although identification of radiocesium in environmental samples is commonly performed by using $$^{134}$$Cs/$$^{137}$$Cs radioactivity ratio, measurement of $$^{134}$$Cs will become challenge in a few decade ago because of short half-life (2 y). Instead of the measurement of $$^{134}$$Cs/$$^{137}$$Cs radioactivity ratio, the measurement of $$^{135}$$Cs/$$^{137}$$Cs isotopic ratio will be effective in future because of long half-life of $$^{135}$$Cs (133 My). In order to measure $$^{135}$$Cs/$$^{137}$$Cs isotopic ratio, Cs must be separated from the matrix of soil. Since 1 Bq of $$^{137}$$Cs is equal to 312.5 fg, large amount of soil have to be treated to extract Cs for the measurement. In the present study, we improved chemical separation method using BOBCalixC6 by optimizing extraction time and reuse of the organic phase. Finally, approximately 170 g of soil sampled at Toka-mura was dissolved and Cs was separate with the developed method to measure $$^{135}$$Cs/$$^{137}$$Cs isotopic ratio.

Oral presentation

Uranium recovery from leachate of sludges generated from nuclear fuel fabrication process, 4; Evaluation of oxide conversion condition after temperature swing extraction process

Kai, Masao; Iwamoto, Toshihiro; Saito, Madoka*; Takahatake, Yoko; Watanabe, So; Nakamura, Masahiro; Tsukahara, Takehiko*; Itoda, Naokazu*; Naruse, Atsuki*

no journal, , 

The sludges containing uranium are generated in nuclear fuel fabrication process and have been stored in nuclear fuel fabrication facilities. Uranium is suggested to be selectively recovered from the solution in which the sludges are immersed. In this study, the oxide conversion tests were carried out with the gel obtained by the temperature swing extraction tests with cerium. The most effective heating temperature for the oxide conversion of was determined as 1000 degree Celsius. Based on the results of tests with cerium, the oxide conversion tests with uranium gel were also carried out. The gel was heated at 1000, and products were specified according to analysis data.

Oral presentation

Development of microscale separation technique for uranium

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

no journal, , 

The adsorption and elution performance of uranium with the microchip column (length 11 mm, column volume 0.39 $$mu$$L) loaded an anion exchange resin for faster and safer radioactive waste analysis were investigated. When a mixed sample of lanthanides and uranium was flown on the microchip column at the feed rate of 1 ml h$$^{-1}$$, uranium could be selectively adsorbed and eluted in about 4 minutes of operation time. This was faster than a conventional column which took several tens of minutes. When this column was applied to uranium separation of the standard seawater, the uranium concentration was determined to be 2.86$$pm$$0.05 ppb, which was in good agreement with the certified value (2.81$$pm$$0.16 ppb). Therefore, the verification test was successful.

Oral presentation

Extraction chromatography technology for MA(III) recovery from spent MOX fuel, 1; Overview of the research project

Sano, Yuichi; Watanabe, So; Takeuchi, Masayuki; Fukumoto, Hiroki*; Arai, Tsuyoshi*; Kim, S.*; Nakase, Masahiko*; Tsukahara, Takehiko*

no journal, , 

The research project on minor actinides recovery using extraction chromatography technology has been carried out for the reduction of volume and radiotoxicity of vitrified products. The overview of this project and main results are described in this paper.

Oral presentation

Design and performance evaluation of microchannel for packing with aion-exchange resins

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

no journal, , 

We designed microchannel for packing with aion-exchange resins that can reduce the radiation exposure risk and the secondary radioactive wastes during uranium (U) separation. Two types of microchips were designed to densely pack the microchannels with resins. The microchannels had almost the same cross-sectional area, but different outer circumferences. A satisfactory separation performance could be obtained by arranging more than ca. 10 resins along the depth and width of the microchannels. The separation performance of the microchannel was evaluated using the seawater standard added Cs-133 as a reference of 1F retained water. The measured value of U in the seawater sample was in good agreement with the certified value. These results indicate that a resin-packed microchannel is suitable for determining the U from highly concentrated matrix elements.

Oral presentation

Local surface and vertical distribution and isotope ratios for radiocesium

Shimada, Asako; Tsukahara, Takehiko*; Nomura, Masao*; Takeda, Seiji

no journal, , 

Because of the accident at the Fukushima Daiichi Nuclear Power Station (1F), a large area of eastern Japan was contaminated by radiocesium. There are many old nuclear facilities in the area. When the old nuclear facilities will be decommissioned in three decades, the radioactive level of radiocesium from 1F would be more than clearance level. When radiocesium would be detected at the completion of their decommissioning in the site, estimation of the origin of which is from background originated 1F and fallout of atmospheric nuclear test or from decommissioned facilities will be important. Therefore, soils of 3 sites were collected by using U8 containers and by core boring, and $$^{137}$$Cs radioactivity, $$^{134}$$Cs/$$^{137}$$Cs radioactivity ratios, $$^{135}$$Cs/$$^{137}$$Cs isotope ratios were determined. Separation method of Cs from soil materials were developed based on the reported methods. The $$^{137}$$Cs radioactivity concentrations were varied in not only between sites but also in the same site, however, $$^{134}$$Cs/$$^{137}$$Cs radioactivity ratio was approximately constant in all sites. In case of highly contaminated soils, $$^{135}$$Cs/$$^{137}$$Cs isotope ratio was almost comparable to that for the soil collected at near the 1F. On the other hand, in case of lower contaminated soils, $$^{135}$$Cs/$$^{137}$$Cs isotope ratio was slightly higher than that for soil collected at near the 1F. It is possibly that fallout before the 1F accident contained $$^{135}$$Cs to increase the $$^{135}$$Cs/$$^{137}$$Cs isotope ratio. In the presentation, vertical distribution will also be discussed.

Oral presentation

Development of dose evaluation method for confirmation of completion of decommissioning, 2; Identification of radiocesium origin using $$^{135}$$Cs/$$^{137}$$Cs isotope ratio

Shimada, Asako; Tsukahara, Takehiko*; Nomura, Masao*; Kim, M. S.*; Shimada, Taro; Takeda, Seiji; Yamaguchi, Tetsuji

no journal, , 

Radiocesium from the Fukushima Daiichi Nuclear Power Station (1F) accident can be treated as background radioactivity at completion of decommissioning, so determining the origin of radiocesium is essential. Therefore, we studied identification of radiocesium origin using $$^{135}$$Cs/$$^{137}$$Cs isotope ratio. The ratio originated from 1F was 0.3628$$pm$$0.0005. When the ratio originated from decommissioning facility was 0.05$$sim$$0.2 larger than that originated from 1F, it is challenging to decrease the stand deviation less than 0.01 for 1 Bq/g of $$^{137}$$Cs because precision was decreased as decreasing the $$^{137}$$Cs concentration. If the ratio is able to be determined within the standard deviation of 0.0005 for 0.5 Bq/g of soil sample, the identification would be available.

24 (Records 1-20 displayed on this page)