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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:0 Percentile:0.01(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

Chemical forms of uranium, thorium and trace elements in sedimentary rocks distributed in Horonobe area, Hokkaido

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.

Journal Articles

Measurement of relative biological effectiveness of protons in human cancer cells using a laser-driven quasimonoenergetic proton beamline

Yogo, Akifumi; Maeda, Takuya; Hori, Toshihiko; Sakaki, Hironao; Ogura, Koichi; Nishiuchi, Mamiko; Sagisaka, Akito; Kiriyama, Hiromitsu; Okada, Hajime; Kanazawa, Shuhei; et al.

Applied Physics Letters, 98(5), p.053701_1 - 053701_3, 2011/02

 Times Cited Count:82 Percentile:94.07(Physics, Applied)

Journal Articles

Zinc isotope fractionation in anion exchange in hydrochloric acid solution

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$$^{-5}$$ to 10$$^{-4}$$ depending on the hydrochloric acid concentration. The maximum isotope fractionation coefficient was obtained in 1 $$M$$ hydrochloric acid, while the distribution coefficient of zinc became maximum at around 2 $$M$$ hydrochloric acid. This difference has been further discussed based on the calculated speciation and structural information derived from X-ray absorption spectroscopy.

Journal Articles

Perspectives on application and flexibility of LWR vitrification technology for high level waste generated from future fuel cycle system

Shiotsuki, Masao; Aoshima, Atsushi; Nomura, Shigeo

Proceedings of International Waste Management Symposium 2006 (WM '06) (CD-ROM), 10 Pages, 2006/02

Achievement of reliable technologies on solidification and disposal of the HLW from future fuel cycle systems such for high burnup LWR, Pu-thermal (MOX), fast breeder reactor (FBR) and their transient stages is one of the most important issues to establish such advanced fuel cycle systems. In this paper, applicability and flexibility of the current vitrification technology for LWR fuel cycle to HLW from the future fuel cycle systems were reviewed by examining characteristics of the HLWs. The current developed vitrification technology is expected to have an advantage for applying to the solidification process of the HLW generated from future fuel cycle systems with some modification/optimization of the melting condition, etc. Moreover, it is thought that the advance aqueous reprocessing system developed for future FBR cycle has the potential which can contribute to the further reducing the number/volume of the HLW. It is also confirmed that development efforts on countermeasure for accumulation of noble metals, which JAEA has been carrying out aiming to accomplishing more stable and reliable operation of the vitrification process and extending the melter's life, will be able to contribute in the future fuel cycle system furthermore.

Oral presentation

Development of water-absorbing porous glass beads, 1; Manufacturing and water-absorbing tests

Suzuki, Tatsuya*; Kaneshiki, Toshitaka*; Nomura, Masao*; Fujii, Yasuhiko; Kobayashi, Hidekazu; Kano, Shigeru; Yamashita, Teruo

no journal, , 

no abstracts in English

Oral presentation

Solidification and leaching property of sludge containing fluoride

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.

Oral presentation

Behavior of trace elements in the fault and altered zones of the Toki granite

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.

Oral presentation

Natural analogue study targeting the fault and altered zones of the Toki granite

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.

Oral presentation

Natural analogue study for migration behavior of trace elements at fault part of the Wakkanai formation, northern Hokkaido

Nakabayashi, Kazuya*; Honda, Teruyuki*; Mizuno, Takashi; Nomura, Masao*

no journal, , 

no abstracts in English

Oral presentation

Solidification and leaching property by time progress of the sludge containing fluoride

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.

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 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

14 (Records 1-14 displayed on this page)
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