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Cs/
Cs isotopic ratio in soil collected near Fukushima Daiichi Nuclear Power Station through mass spectrometryShimada, 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：5 Percentile：65.59(Nuclear Science & Technology)Determining the completeness of nuclear reactor decommissioning is an important step in safely utilizing nuclear power. For example, Cs from the Fukushima Daiichi Nuclear Power Station (FDNPS) accident can be treated as background radioactivity, so determining the origin of Cs is essential. To accomplish this, measuring the Cs/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
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 Cs/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 Cs/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 
Cs/Cs activity distributions, suggesting that this ratio may be useful in identifying radiocesium origins for evaluating future nuclear reactor decommissions.
Kosemura, Takashi*; Honda, Teruyuki*; Mizuno, Takashi; Murakami, Hiroaki; Nomura, Masao*
Fisshion, Torakku Nyusureta, (26), p.16 - 20, 2013/00
We Analyze existence form of REE in the rock from HDB-6 borehole at the Horonobe Town, Hokkaido. As a result, U and Th is mainly sulfate at fault. REE is mainly silicate at fault.
Suzuki, Tatsuya*; Nomura, Masao*; Fujii, Yasuhiko*; Ikeda, Atsushi; Takaoka, Toru*; Oguma, Koichi*
Nihon Ion Kokan Gakkai-Shi, 21(3), p.328 - 333, 2010/09
Zinc isotope fractionation in an anion exchange resin has been investigated in hydrochloric acid solution by chromatographic technique. It was found that the heavier zinc isotopes were located disproportionately in the solution phase. The isotope fractionation coefficient was varied from the order of 10
to 10
depending on the hydrochloric acid concentration. The maximum isotope fractionation coefficient was obtained in 1 
hydrochloric acid, while the distribution coefficient of zinc became maximum at around 2 hydrochloric acid. This difference has been further discussed based on the calculated speciation and structural information derived from X-ray absorption spectroscopy.
*; Akatsuka, Hiroshi*; *; Suzuki, Tatsuya*; *; *;
JNC TY9400 2000-009, 41 Pages, 2000/03
JNC-TY9400-2000-009.pdf:1.22MB
no abstracts in English
Fujie, Makoto; *; *; *
Journal of Nuclear Science and Technology, 23(4), p.330 - 337, 1986/00
Times Cited Count：46 Percentile：96.4(Nuclear Science & Technology)no abstracts in English
Suzuki, Tatsuya*; Kaneshiki, Toshitaka*; Nomura, Masao*; Fujii, Yasuhiko; Kobayashi, Hidekazu; Kano, Shigeru; Yamashita, Teruo
no journal, ,
no abstracts in English
Tsunashima, Yasumichi; Shimazaki, Masao; Ohashi, Yusuke; Tanaka, Yoshio; Nomura, Mitsuo
no journal, ,
The operation waste of uranium conversion plant and uranium enrichment plant is called sludge, and contains many fluoride which is deleterious material. For disposal, elution of fluoride is a problem. Moreover, sludge contains many calcium sulfate and we are anxious about expansion of cement solidification object by superfluous generation ofettringite. Therefore, we report solidification and the leaching property of the cement solidification object of the sludge containing many fluoride. Moreover, we report solidification and the leaching property of sludge using magnesium oxide solidification material as a method of controlling elution and expansion of fluoride.
Arai, Yusuke*; Honda, Teruyuki*; Iwatsuki, Teruki; Nomura, Masao*
no journal, ,
Rare earth elements (REEs) in altered part and fault of Toki granite were analyzed to understand mobility in deep environment. REEs occurs in an oxidized minerals at altered part, in a carbonates and ion exchangeable minerals at fault, respectively. Light REEs tend to be involved in sulphide or phosphorate minerals and heavy REEs seem to be in clay, carbonate minerals. These results imply that the migration of minor actinoides in granite might be retarded by such minerals in fracture and fault.
Arai, Yusuke*; Honda, Teruyuki*; Iwatsuki, Teruki; Nomura, Masao*
no journal, ,
The occurrence of rare earth elements in alteration rock and fault of Toki granite was observed to infer the migration process of minor actinides. The light rare earth elements concentrated in alteration rock and fault compared to fresh rock due to precipitation as a secondary mineral and adsorption onto clay minerals. This suggests the possibility of retardation of minor actinides by alteration minerals.
Nakabayashi, Kazuya*; Honda, Teruyuki*; Mizuno, Takashi; Nomura, Masao*
no journal, ,
no abstracts in English
Tsunashima, Yasumichi; Ohashi, Yusuke; Shimazaki, Masao; Nomura, Mitsuo; Tanaka, Yoshio
no journal, ,
The operation waste of uranium conversion plant and uranium enrichment plant is called sludge, and contains many fluoride which is deleterious material. For disposal, elution of fluoride is a problem. Moreover, sludge contains many calcium sulfate and we are anxious about expansion of cement solidification object by superfluous generation of Ettringite. In order to solve these subjects, the solidification examination of the sludge which used calcium hydrogen phosphate is considered as magnesium oxide system solidification material. The solidification and leaching property by time progress of the sludge containing fluoride are reported.
Cs/Cs isotope ratio near the Fukushima Daiichi Nuclear Power StationShimada, Asako; Tsukahara, Takehiko*; Nomura, Masao*; Shimada, Taro; Takeda, Seiji
no journal, ,
no abstracts in English
Cs/Cs isotope ratioShimada, 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 Cs/Cs isotope ratio. The ratio originated from 1F was 0.3628
0.0005. When the ratio originated from decommissioning facility was 0.05
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 Cs because precision was decreased as decreasing the 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.
Cs/Cs isotope ratio in environmental soil samplesShimada, Asako; Kim, M. S.*; Tsukahara, Takehiko*; Nomura, Masao*; Shimada, Taro; Takeda, Seiji; Yamaguchi, Tetsuji
no journal, ,
no abstracts in English
Cs/Cs isotopic ratio in environmental samplesShimada, Asako; Nomura, Masao*; Tsukahara, Takehiko*; Takeda, Seiji
no journal, ,
Although identification of radiocesium in environmental samples is commonly performed by using Cs/Cs radioactivity ratio, measurement of Cs will become challenge in a few decade ago because of short half-life (2 y). Instead of the measurement of Cs/Cs radioactivity ratio, the measurement of Cs/Cs isotopic ratio will be effective in future because of long half-life of Cs (133 My). In order to measure Cs/Cs isotopic ratio, Cs must be separated from the matrix of soil. Since 1 Bq of 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 Cs/Cs isotopic ratio.
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 Cs radioactivity, Cs/Cs radioactivity ratios, Cs/Cs isotope ratios were determined. Cs radioactivity concentrations were varied in not only between sites but also in the same site, however, Cs/Cs radioactivity ratio was approximately constant in all sites. In case of highly contaminated soils, Cs/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, Cs/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 Cs to increase the Cs/Cs isotope ratio.
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 Cs radioactivity, Cs/Cs radioactivity ratios, Cs/Cs isotope ratios were determined. Separation method of Cs from soil materials were developed based on the reported methods. The Cs radioactivity concentrations were varied in not only between sites but also in the same site, however, Cs/Cs radioactivity ratio was approximately constant in all sites. In case of highly contaminated soils, Cs/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, Cs/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 Cs to increase the Cs/Cs isotope ratio. In the presentation, vertical distribution will also be discussed.
