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Journal Articles

Development of Cs separation methods from large amounts of soil samples to determine the $$^{135}$$Cs/$$^{137}$$Cs isotope ratio

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

Journal of Radioanalytical and Nuclear Chemistry, 333(12), p.6297 - 6310, 2024/12

 Times Cited Count:0 Percentile:0.00(Chemistry, Analytical)

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:25.07(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:3.74(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:7 Percentile:61.36(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:13.57(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

$$^{135}$$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 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

Evaluation of remaining spent extraction solvent in vermiculite by PIXE analysis

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

no journal, , 

Oral presentation

Uranium recovery from the solution originated sludge waste, 3; Evaluation of several extractants on cerium (IV) nitrate separation using thermoresponsive polymer

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

no journal, , 

The sludge generated production of nuclear fuel contained uranium has been storage. The sludge is immersed in some kinds of solution. After immersion, uranium is recovered from the solution. Cerium extractive tests using thermoresponsive polymer was carried out on two kinds of extractants. C14-BAMA was found to be superior, and we plan to conduct a uranium study on this extractant.

Oral presentation

Uranium recovery from the solution originated sludge waste, 2; Comparison study of uranyl nitrate separation methods by monoamide extractant

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

no journal, , 

The sludge contained uranium generated production of nuclear fuel has been storage. The sludge is immersed in some kinds of solution. After immersion, uranium is recovered from the solution. Solvent extraction method, extraction chromatography and gelling extraction method were conducted on uranyl nitrate solution using monoamide extractant to compare on amount of waste and running cost on each methods. The gelling extraction method was superior to other two methods.

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

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

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

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.

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

Basic research programs of vitrification technology for waste volume reduction, 96; Development of on-line monitoring technique of target elements for chromatographic valve control

Tsukahara, Takehiko*; Brandt, A.*; Watanabe, So; Sano, Yuichi; Takeuchi, Masayuki

no journal, , 

no abstracts in English

25 (Records 1-20 displayed on this page)