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Journal Articles

Simple pretreatment method for tritium measurement in environmental water samples using a liquid scintillation counter

Nakasone, Shunya*; Yokoyama, Sumi*; Takahashi, Tomoyuki*; Ota, Masakazu; Kakiuchi, Hideki*; Sugihara, Shinji*; Hirao, Shigekazu*; Momoshima, Noriyuki*; Tamari, Toshiya*; Shima, Nagayoshi*; et al.

Plasma and Fusion Research (Internet), 16, p.2405035_1 - 2405035_5, 2021/02

Removal of impurities such as organic and other types of dissolved matters from environmental water samples is required for precise analysis of tritium with a liquid scintillation counting method. In general, a distillation method is a conventional one for tritium analysis in environmental water samples, but is a time-consuming process that takes 24 hours for removal of impurities. We have proposed a rapid pretreatment method for tritium analysis, that uses ion exchange resins. In this study, we performed batch experiments, to evaluate the effectiveness of the ion exchange resins on the tritium measurement. The results obtained demonstrated that removal of impurities in the sample water by ion exchange resins can be achieved during a short period of time (i.e., in 5 min).

Journal Articles

Preliminary investigation of pretreatment methods for liquid scintillation measurements of environmental water samples using ion exchange resins

Nakasone, Shunya*; Yokoyama, Sumi*; Takahashi, Tomoyuki*; Ota, Masakazu; Kakiuchi, Hideki*; Sugihara, Shinji*; Hirao, Shigekazu*; Momoshima, Noriyuki*; Tamari, Toshiya*; Shima, Nagayoshi*; et al.

Plasma and Fusion Research (Internet), 15, p.2405027_1 - 2405027_3, 2020/05

A quick preprocessing system for tritium analysis of environmental samples is important to judge environmental influence of tritium releases due to accident or tritium-handling facilities. Analysis of tritium in water samples with liquid scintillation counting method requires removal of impurities such as organic matter and ion species from water samples. Generally, a distillation method is adopted as a pretreatment of analysis for tritium; however, the distillation method is a time-consuming process. The aim of this study is to evaluate a rapid pretreatment method for tritium analysis with ion exchange resin. From batch and column experiments that used inland water and ion exchange resin, we confirmed removals of impurities of the water sample and that the removal of impurities was possible for a short time (by 5 minutes).

Journal Articles

Development of field estimation technique and improvement of environmental tritium behavior model

Yokoyama, Sumi*; Takahashi, Tomoyuki*; Ota, Masakazu; Kakiuchi, Hideki*; Sugihara, Shinji*; Hirao, Shigekazu*; Momoshima, Noriyuki*; Tamari, Toshiya*; Shima, Nagayoshi*; Atarashi-Andoh, Mariko; et al.

Plasma and Fusion Research (Internet), 14(Sp.2), p.3405099_1 - 3405099_4, 2019/06

The Large Helical Device of the National Institute for Fusion Science started D-D experiments in 2017. To ensure the safety of the facility, it is important to develop evaluation methods for environmental tritium transfer. Tritiated water (HTO) in atmosphere and soil is transferred to plants, and organically bound tritium (OBT) is formed by photosynthesis. Prediction of OBT formation is important, because OBT accumulates in plants and causes dose through ingestion. The objective of this study is to estimate environmental tritium transfer using a simple compartment model and practical parameters. We proposed a simple compartment model consisting of air-soil-plant components, and tried to validate the model by comparison with a sophisticated model, SOLVEG. In this study, we plan to add wet deposition to the model and obtain parameters from measurements of soil permeability and tritium concentrations in air, soil and plants. We also establish rapid pretreatment methods for OBT analysis.

JAEA Reports

Potassium-Argon (K-Ar) dating for fault gouge samples in the Tono Geoscience Center

Tamura, Hajimu*; Shibata, Kenji*; Takahashi, Naoya; Niwa, Masakazu

JAEA-Testing 2017-001, 52 Pages, 2017/03

JAEA-Testing-2017-001.pdf:2.36MB

It is essential to understand the activity of faults in and around a target area to assess the long-term geosphere stability for geological isolation. Potassium-Argon (K-Ar) dating of fault gouge has been conducted in Tono Geoscience Center as one of the dating technique for faulting. This report includes methods for sample preparation, analyses, and age calculation on the K-Ar dating. This can contribute to an evaluation of calculated K-Ar ages.

Journal Articles

Depth profiles of radioactive cesium in soil using a scraper plate over a wide area surrounding the Fukushima Dai-ichi Nuclear Power Plant, Japan

Matsuda, Norihiro; Mikami, Satoshi; Shimoura, Susumu*; Takahashi, Junko*; Nakano, Masakazu; Shimada, Kiyotaka*; Uno, Kiichiro; Hagiwara, Shigetomo; Saito, Kimiaki

Journal of Environmental Radioactivity, 139, p.427 - 434, 2015/01

 Times Cited Count:98 Percentile:94.54(Environmental Sciences)

Journal Articles

Fabrication of super electromagnetic coil support using HIP diffusion bonding

Takahashi, Masakazu*; Masuo, Hiroshige*; Takano, Katsutoshi; Koizumi, Norikiyo

Proceedings of 11th International Conference on Hot Isostatic Pressing (HIP 2014), 4 Pages, 2014/06

As part of the research and development of Tokamak-type nuclear fusion reactors, super electromagnetic coils are required to control the plasma reaction. The structure that supports the plasmas chamber is maintained at cryogenic temperatures in liquid helium and thus must be able to withstand the extremes of this type of environment. The most promising material for this support is, SUS316LNH and at present, the only fabrication method being employed is traditional machining from solid materials. This creates a large amount of waste material with extremely long fabrication time, due to the large size of the support at 13 m in height and 8 m in width. Therefore, it is thought that by combining machining with the HIP diffusion bonding process, both waste and fabrication time can be reduced. Although this method is still under development, it is believed that a reduction of about 50% in wasted material and an about 40% in machining time can be achieved.

Journal Articles

Development of function-graded proton exchange membrane for PEFC using heavy ion beam irradiation

Shiraki, Fumiya*; Yoshikawa, Taeko*; Oshima, Akihiro*; Oshima, Yuji*; Takasawa, Yuya*; Fukutake, Naoyuki*; Oyama, Tomoko*; Urakawa, Tatsuya*; Fujita, Hajime*; Takahashi, Tomohiro*; et al.

Nuclear Instruments and Methods in Physics Research B, 269(15), p.1777 - 1781, 2011/08

 Times Cited Count:7 Percentile:53.54(Instruments & Instrumentation)

The graded energy deposition of heavy ion beam irradiation to polymeric materials was utilized to synthesize a novel proton exchange membrane (PEM) with the graded density of sulfonic acid groups toward the thickness direction. Stacked Poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) films were irradiated by Xe$$^{54+}$$ ion beam with the energy of 6 MeV/u under a vacuum condition. Irradiated films were grafted with styrene monomer and then sulfonated. The membrane electrode assembly (MEA) fabricated by the function graded PEM showed improved fuel cell performance in terms of voltage stability. It was expected that the function-graded PEM could control the graded concentration of sulfonic acid groups in PEM.

Journal Articles

Micro-fabrication of biodegradable polymers using focused ion beam

Okubo, Satoshi*; Takahashi, Tomohiro*; Takasawa, Yuya*; Gowa, Tomoko*; Sasaki, Takashi*; Nagasawa, Naotsugu; Tamada, Masao; Oshima, Akihiro*; Tagawa, Seiichi*; Washio, Masakazu*

Journal of Photopolymer Science and Technology, 23(3), p.393 - 397, 2010/11

 Times Cited Count:4 Percentile:13.86(Polymer Science)

Microfabrication of biodegradable polymers such as poly(butylene succinate-${it co}$-adipate) (PBSA) and poly($$varepsilon$$-caprolactone) (PCL) were demonstrated using focused ion beam (FIB) with maskless direct etching. As the result, the micro structures of PBSA and PCL were obtained. The etching depth of both PBSA and PCL were increased with increasing FIB fluence, and the etching rates were estimated to be about 1.3 $$times$$ 10$$^{-18}$$ $$mu$$m/(ions cm$$^{-2}$$) and 1.2 $$times$$ 10$$^{-18}$$ $$mu$$m/(ions cm$$^{-2}$$), respectively. Moreover, very thin films of PBSA and PCL were made by spin-coating method. The thicknesses of the spin-coated samples were about 200 nm, and the surface roughness was less than 10 nm (RMS). The fine structures such as micro-gear of PBSA and PCL were obtained without solid debris. The line width of the fabricated structure was about 250 nm.

Journal Articles

Ion beam irradiation effects on resist materials

Gowa, Tomoko*; Takahashi, Tomohiro*; Oka, Toshitaka; Murakami, Takeshi*; Oshima, Akihiro*; Tagawa, Seiichi*; Washio, Masakazu*

Journal of Photopolymer Science and Technology, 23(3), p.399 - 404, 2010/08

Oral presentation

Spatial distribution and features of fracture zones in and around the Atotsugawa Fault, northern Gifu Prefecture

Niwa, Masakazu; Ishimaru, Tsuneari; Kurosawa, Hideki; Shimada, Koji; Moriya, Toshifumi*; Takahashi, Kazuharu*

no journal, , 

It is suggested that fracture zones formed by fault activities have an effect on hydrologic feature of surrounding rocks. Spatial distribution and features of fracture zones in surveyed areas are informative for site selection and design of geological repositories. Here we show a case study in the Atotsugawa Fault, northern Gifu Prefecture. Field mapping in the study area indicates that the number of fracture zone is sharply reduced, and width of each fracture zones falls within 2 m, with distance of more than 500 m from the surface trace of the Atotsugawa Fault.

Oral presentation

Study on direct etching of fluoropolymers by heavy ion beam irradiation

Takasawa, Yuya*; Fukutake, Naoyuki*; Takahashi, Tomohiro*; Urakawa, Tatsuya*; Oshima, Yuji*; Gowa, Tomoko*; Shiraki, Fumiya*; Fujita, Hajime*; Oka, Toshitaka; Murakami, Takeshi*; et al.

no journal, , 

Oral presentation

Development of functionally-graded materials using high energy heavy ion beam

Oshima, Akihiro*; Shiraki, Fumiya*; Takasawa, Yuya*; Fujita, Hajime*; Yoshikawa, Taeko*; Tatsumi, Takahiro*; Tsubokura, Hidehiro*; Takahashi, Tomohiro*; Gowa, Tomoko*; Sakaue, Kazuyuki*; et al.

no journal, , 

no abstracts in English

Oral presentation

Study of complex magnetic structures in frustrated magnets by means of polarized neutrons

Kakurai, Kazuhisa; Wakimoto, Shuichi; Matsuda, Masaaki*; Ishiwata, Shintaro*; Okuyama, Daisuke*; Taguchi, Yasujiro*; Tokura, Yoshiki*; Nishi, Masakazu*; Nakajima, Taro*; Mitsuda, Setsuo*; et al.

no journal, , 

Oral presentation

Development of true coincidence summing correction for cascade $$gamma$$-ray emitters including $$^{134}$$Cs, 1; Collaborative experiment by the committee on preparation of reference materials for radioactivity analysis of JSAC

Yonezawa, Chushiro*; Kakita, Kazutoshi*; Takahashi, Takanori*; Aono, Tatsuo*; Maeda, Satoshi; Abe, Takaaki*; Arakawa, Fumihiro*; Kiho, Nobuharu*; Akiyama, Masakazu*; Muramatsu, Isamu*; et al.

no journal, , 

no abstracts in English

Oral presentation

A Distribution map of submerged terraces around the Japanese Islands based on the interpretation of submarine anaglyph images

Komatsu, Tetsuya; Izumida, Atsuto*; Takahashi, Takayuki*; Funatsu, Taro*; Muraki, Masahiro*; Hozo, Renya*; Nomura, Katsuhiro; Niwa, Masakazu; Sugai, Toshihiko*

no journal, , 

no abstracts in English

Oral presentation

Chemical speciation of potassium in altered minerals from Miocene andesite in the west coast of the Noto Peninsula and their K-Ar ages

Unami, Kensuke*; Fukushi, Keisuke*; Takahashi, Yoshio*; Itaya, Tetsumaru*; Niwa, Masakazu

no journal, , 

K-Ar dating is generally not applicable to smectite, which is potassium-free clay mineral. However, based on multidisciplinary analyses such as XRD, TEM, exchangeable cation analysis, and XAFS, fixed potassium can exists in clay minerals in which only smectite is identified by XRD analysis.

Oral presentation

Form of potassium in clay minerals from Miocene andesite in the west coast of the Noto Peninsula

Unami, Kensuke*; Fukushi, Keisuke*; Takahashi, Yoshio*; Niwa, Masakazu

no journal, , 

Based on our analysis of XAFS, TEM, etc., we found that our analyzed clay minerals include potassium-fixed structure like illite, even if only smectite is identified in them according to XRD analysis.

Oral presentation

Improvement of environmental tritium behavior model; Calculation of OBT concentration in plants using the MOGRA code

Yokoyama, Sumi*; Takahashi, Tomoyuki*; Ota, Masakazu; Kakiuchi, Hideki*; Sugihara, Shinji*; Hirao, Shigekazu*; Momoshima, Noriyuki*; Tamari, Toshiya*; Shima, Nagayoshi*; Atarashi-Andoh, Mariko; et al.

no journal, , 

To ensure safety of fusion facilities, it is important to develop evaluation methods for tritium transfer in the environment. For estimation of tritium transfer in the terrestrial environment, we had developed a simple compartment model using the Migration Of GRound Additions (MOGRA) code. The model was composed by an air-soil-plant system. The target source terms were HT and HTO in the air. In addition, wet deposition was modeled by input of HTO to the system by rainfall. Tritium in the plant was divided into free water tritium (FWT) and organically bound tritium (OBT). The tritium concentration in the environmental medium was trial calculated for chronic and accidental HTO releases to the atmosphere, as preliminary calculation run of the model.

Oral presentation

Development of a new sampler for tritium measurement in the infiltrated soil water

Kakiuchi, Hideki*; Tanaka, Masahiro*; Fukutani, Satoshi*; Sugihara, Shinji*; Hirao, Shigekazu*; Momoshima, Noriyuki*; Tamari, Toshiya*; Shima, Nagayoshi*; Atarashi-Andoh, Mariko; Furukawa, Masahide*; et al.

no journal, , 

no abstracts in English

19 (Records 1-19 displayed on this page)
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