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Journal Articles

Anion-exchange separation of americium and the lanthanides using a single column

Miyamoto, Yutaka; Yasuda, Kenichiro

Journal of Nuclear and Radiochemical Sciences (Internet), 18, p.13 - 15, 2018/07

A sequential separation technique using an anion-exchange column developed in the previous works have the potential to completely separate picograms of Am from the lanthanides using mixtures of acetic acid, hydrochloric acid, and nitric acid as the eluents, without any functional ligands or special columns. This experimental result implies that ultra-trace actinides, including Am, Pu, U, and Th in environmental samples can be sequentially separated by combination of these mixed-media eluents and an anion exchange column.

Journal Articles

Accurate sensitive analytical technique of ultra-trace plutonium in the IAEA environmental samples

Miyamoto, Yutaka; Yasuda, Kenichiro; Suzuki, Daisuke; Esaka, Fumitaka; Magara, Masaaki

KEK Proceedings 2017-6, p.292 - 298, 2017/11

Our updated analytical techniques of ultra-trace plutonium in the IAEA environmental samples by ICP-MS were mentioned. Some careful techniques to accurately determine ultra-trace plutonium in the range of femto-grams to pico-grams were introduced. The uncertainties of analytical results were estimated according to the GUM concept. Our trials of determination of sub-femto grams americium in an environmental sample were also mentioned.

Journal Articles

Analysis of plutonium isotope ratios including $$^{238}$$Pu/$$^{239}$$Pu in individual U-Pu mixed oxide particles by means of a combination of alpha spectrometry and ICP-MS

Esaka, Fumitaka; Yasuda, Kenichiro; Suzuki, Daisuke; Miyamoto, Yutaka; Magara, Masaaki

Talanta, 165, p.122 - 127, 2017/04

 Times Cited Count:4 Percentile:47.81(Chemistry, Analytical)

The isotope ratios of $$^{238}$$Pu/$$^{239}$$Pu, $$^{240}$$Pu/$$^{239}$$Pu, $$^{241}$$Pu/$$^{239}$$Pu, and $$^{242}$$Pu/$$^{239}$$Pu were measured for individual Pu and U-Pu mixed oxide particles by a combination of alpha spectrometry and inductively coupled plasma mass spectrometry (ICP-MS). As a consequence, we were able to determine the $$^{240}$$Pu/$$^{239}$$Pu, $$^{241}$$Pu/$$^{239}$$Pu, and $$^{242}$$Pu/$$^{239}$$Pu isotope ratios with ICP-MS after particle dissolution and chemical separation of uranium, plutonium and americium with UTEVA resins. Furthermore, $$^{238}$$Pu/$$^{239}$$Pu isotope ratios were able to be calculated by using both the $$^{238}$$Pu/( $$^{239}$$Pu+$$^{240}$$Pu) activity ratios that had been measured through alpha spectrometry and the $$^{240}$$Pu/$$^{239}$$Pu isotope ratios determined through ICP-MS. Therefore, the combined use of alpha spectrometry and ICP-MS is useful in determining plutonium isotope ratios, including $$^{238}$$Pu/$$^{239}$$Pu, in individual U-Pu mixed oxide particles.

Journal Articles

Summary of study on environmental radioactivity effected from the accident at the TEPCO Fukushima Daiichi Nuclear Power Plant in 5 years after the accident

Iimoto, Takeshi*; Kinoshita, Norikazu*; Sakaguchi, Aya*; Sugihara, Shinji*; Takamiya, Koichi*; Tagami, Keiko*; Nagao, Seiya*; Bessho, Kotaro*; Matsumura, Hiroshi*; Miura, Taichi*; et al.

KEK Report 2016-3, 134 Pages, 2017/03

This report is summary of study on environmental radioactivity effected from the accident at the TEPCO Fukushima Daiichi Nuclear Power Plant in 5 years after the accident. It was compiled efforts related to the accident reported from the 13th to the 17th "Workshop on Environmental Radioactivity" which was held at the High Energy Accelerator Research and Development Organization.

Journal Articles

Automatic sequential separation with an anion-exchange column for ultra-trace analysis of Pu, U, Th, Pb, and lanthanides in environmental samples

Miyamoto, Yutaka; Yasuda, Kenichiro; Magara, Masaaki

Journal of Radioanalytical and Nuclear Chemistry, 309(1), p.303 - 308, 2016/07

 Times Cited Count:1 Percentile:76.09(Chemistry, Analytical)

The technique of sequential separation for U, Th, Pb, lanthanides and Pu using a single anion-exchange column and mixed acids media were developed. An automatic system utilizing a small column and pressurized gas was assembled for this sequential separation. By adjusting the eluent chemical composition for Pu separation, this separation technique has been achieved. Some pieces of tree ring sample were digested, and ultra-trace U and Pu in the samples were separated by this system. The analytical results of U and Pu measured by mass spectrometry will be mentioned.

Journal Articles

Chemical separation of ultra-trace multi-elements in environmental samples

Miyamoto, Yutaka; Yasuda, Kenichiro; Magara, Masaaki

KEK Proceedings 2015-4, p.44 - 48, 2015/11

We developed an automatic system for sequential separation with an anion-exchange column to simply and quickly separate less than pico-grams of ultra-trace U, Th, Pb, the lanthanide, and Pu in an environmental sample without foreign contamination. The objective sequential separation of ultra-trace multi-elements succeeded by choosing the HCl-HF mixture based acetic acid for Th separation and the HCl-diluted HF mixture for Pu separation. The objective elements in a multi-elements mixture were completely separated for 6 h 15 min by use of the automatic system and the optimized separation condition.

Journal Articles

Sequential separation of ultra-trace U, Th, Pb, and lanthanides using a simple automatic system

Miyamoto, Yutaka; Yasuda, Kenichiro; Magara, Masaaki

Analyst, 140(13), p.4482 - 4488, 2015/07

 Times Cited Count:3 Percentile:78.55(Chemistry, Analytical)

Uranium, Thorium, lead, and the lanthanides were automatically and sequentially separated with a single anion-exchange column. This separation was achieved using eluents consisting of simple and highly pure acid mixture of HCl, HNO$$_3$$, acetic acid, and HF. This simple, automatic system is driven with pressurized nitrogen gas, and controlled by a computer program. For an evaluation examination, a reference powdered rock sample was separated by using this system. Abundances of objective elements, including 0.23 ng of lutetium, were accurately determined without corrections of chemical recovery yield or subtraction of processing blank. This separation technique saves time and effort for chemical processing, and it is useful for ultra-trace quantitative and isotopic analyses of elements in small environmental samples.

JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JPDR facilities, 4

Omori, Hiroyuki; Nebashi, Koji; Shimada, Asako; Tanaka, Kiwamu; Yasuda, Mari; Hoshi, Akiko; Tsuji, Tomoyuki; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2014-029, 31 Pages, 2015/03

JAEA-Data-Code-2014-029.pdf:1.51MB

Simple and rapid methods to evaluate the radioactivity concentrations are required for the radioactive waste generated from research facilities in the Japan Atomic Energy Agency to dispose of in a near-surface repository. In order to establish the methods to evaluate the radioactivity concentrations of miscellaneous solid waste generated from research and testing reactors, we collected and analyzed samples from miscellaneous solid waste generated by the decommissioning of JPDR (Japan Power Demonstration Reactor). In this report, we reported the analytical data determined in fiscal 2014 ($$^{137}$$Cs and $$^{93}$$Mo) and summarized them with the radioactivity concentrations obtained in the past as basic data to consider the evaluation method of radioactivity concentrations in the stored waste taken from JPDR.

Journal Articles

Radionuclide release to stagnant water in the Fukushima-1 Nuclear Power Plant

Nishihara, Kenji; Yamagishi, Isao; Yasuda, Kenichiro; Ishimori, Kenichiro; Tanaka, Kiwamu; Kuno, Takehiko; Inada, Satoshi; Goto, Yuichi

Journal of Nuclear Science and Technology, 52(3), p.301 - 307, 2015/03

 Times Cited Count:10 Percentile:12.68(Nuclear Science & Technology)

After the severe accident at the Fukushima-1 nuclear power plant, large amounts of contaminated stagnant water have accumulated in turbine buildings and their surroundings. This rapid communication reports calculation of the radionuclide inventory in the core, collection of measured inventory in the stagnant water, and estimation of radionuclide release ratios from the core to the stagnant water. This evaluation is based on data obtained before June 3, 2011. The release ratios of tritium, iodine, and cesium were several tens of percent, whereas those of strontium and barium were smaller by one or two orders of magnitude. The release ratios in the Fukushima accident were equivalent to those in the TMI-2 accident.

Journal Articles

On-site monitoring method of radioactive cesium in water sample using cesium adsorption disk and GM survey meter

Nagano, Tetsushi; Mitamura, Hisayoshi; Yanase, Nobuyuki; Naganawa, Hirochika; Yasuda, Kenichiro; Yamaguchi, Hiroaki*

Hoshasei Busshitsu No Kyuchaku, Josen Oyobi Taihoshasen Gjutsu Ni Okeru Zairyo, Seko, Sokutei No Shin Gijutsu, p.400 - 408, 2014/11

A method for monitoring radioactive cesium concentration in water using a cesium adsorption disk and a GM survey meter has been developed to ascertain whether the water quality meets standards on radiological contaminants in water. This method was successfully applied to monitoring of decontaminated water of an outdoor school swimming pool in Date City after Fukushima Daiichi Nuclear Power Plant accident.

Journal Articles

Comparative Study on Decay Ratios of Laser-induced Fluorescence between Asbestos and Building Materials

Ozu, Akira; Esaka, Fumitaka; Yasuda, Kenichiro

Bunseki Kagaku, 63(7), p.609 - 617, 2014/07

AA2013-0047.pdf:1.5MB

 Percentile:100(Chemistry, Analytical)

Decay ratios of the laser-induced fluorescence emitted from five types of asbestos and six types of building materials in the broad wavelength region from 350 to 700 nm were investigated by using an ultraviolet laser pulse of 266 nm. Dependence of the decay ratios on the wavelength were compared, and evaluated in an attempt to numerically discriminate asbestos from the other building materials. It was observed that the decay ratios of each material were not constant over the wavelength region and varied in the wavelength over time. The fluorescence of asbestos and the building materials except for rock fiber at above 500 nm decayed faster than that at below 500 nm. The wavelength region from 405 to 420 nm was found optimum to identify types of asbestos and to discriminate asbestos from the building materials by comparing the decay ratio at the delay time of 10 ns after the incidence of laser pulse.

Journal Articles

Size distribution of radioactive particles collected at Tokai, Japan 6 days after the nuclear accident

Miyamoto, Yutaka; Yasuda, Kenichiro; Magara, Masaaki

Journal of Environmental Radioactivity, 132, p.1 - 7, 2014/06

 Times Cited Count:17 Percentile:29.49(Environmental Sciences)

Airborne radioactive particles released by the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in 2011 were collected with a cascade low-pressure impactor at the Japan Atomic Energy Agency (JAEA) in Tokai. Size-fractionated samples were collected twice, in the periods of March 17 - April 1, 2011, and May 9-13, 2011. These size-fractionated samplings were carried out in the earliest days at a short distance from the FDNPPs. Radioactivity of short-lived nuclides (several ten days of half-life) were determined as well as $$^{134}$$Cs and $$^{137}$$Cs. The elemental composition of size-fractionated samples was also measured. In the first collection, the activity median aerodynamic diameter (AMAD) of $$^{rm 129m}$$Te, $$^{134}$$Cs, $$^{136}$$Cs and $$^{137}$$Cs was 1.5-1.6$$mu$$m, while the diameter of $$^{131}$$I was 0.45$$mu$$m.

Journal Articles

Method for monitoring radioactive cesium concentration in water using cesium adsorption disk and GM survey meter

Nagano, Tetsushi; Mitamura, Hisayoshi; Yanase, Nobuyuki; Naganawa, Hirochika; Yasuda, Kenichiro; Yoshida, Zenko; Yamaguchi, Hiroaki*

Nippon Hoshasen Anzen Kanri Gakkai-Shi, 11(2), p.139 - 145, 2012/11

An on-site monitoring method for radioactive cesium concentration in water using a cesium adsorption disk and a GM survey meter has been developed to rapidly and easily ascertain whether the water quality meets standards on radiological contaminants in water. In this method, both dissolved and suspended forms of radioactive cesium are collected on the cesium adsorption disk by means of filtration of a water sample. Beta counting rate of the disk is converted into radioactivity using a conservative calibration factor obtained here. The present on-site method was applied to monitoring of decontaminated water of an outdoor school swimming pool in Date city after Fukushima Dai-ichi Nuclear Power Plant accident.

Journal Articles

Radionuclide release to stagnant water in Fukushima-1 Nuclear Power Plant

Nishihara, Kenji; Yamagishi, Isao; Yasuda, Kenichiro; Ishimori, Kenichiro; Tanaka, Kiwamu; Kuno, Takehiko; Inada, Satoshi; Goto, Yuichi

Nippon Genshiryoku Gakkai Wabun Rombunshi, 11(1), p.13 - 19, 2012/03

After the severe accident in the Fukushima-1 Nuclear Power Plant, large amount of contaminated stagnant water has been produced in turbine buildings and those surroundings. This rapid communication reports calculation of radionuclide inventory in the core, collection of measured inventory in the stagnant water, and estimation of radionuclide release ratios from the core to the stagnant water. The present evaluation is based on data obtained before June 3, 2011.

Journal Articles

Sequential anion-exchange separation of trace U, Th, Pb and lanthanides in environmental samples

Miyamoto, Yutaka; Yasuda, Kenichiro; Magara, Masaaki; Kimura, Takaumi; Usuda, Shigekazu*

Proceedings in Radiochemistry, 1(1), p.209 - 212, 2011/09

Nano grams of U, Th, Pb and lanthanides in a geological reference rock were sequentially separated with a single anion-exchange column. Mixture of acetic acid, HCl and HNO$$_{3}$$ were used as the eluents for this separation. The recovery of these key elements was more than 95%, and there was no fractionation among the recoveries of each lanthanide element. Alkaline metals, alkaline earth metals and Fe were effectively eliminated from the key elements. By using this technique, it is possible to simplify the complicated traditional processes without any special ligands, columns and equipments.

Journal Articles

Identification of asbestos by laser-induced fluorescence microscopy

Ozu, Akira; Esaka, Fumitaka; Yasuda, Kenichiro

Bunseki Kagaku, 60(1), p.75 - 80, 2011/01

 Percentile:100(Chemistry, Analytical)

Microscopic studies on laser-induced fluorescence emitted from asbestos (chrysotile) and a building material (glass-wool: a substitute material for asbestos) fibrous particle excited by a ultra-violet (266 nm) laser, have been conducted by visualizing those particles with the fluorescence. The fluorescence characteristics observed under the microscope agreed approximately with those observed in the determination using bulk samples. The decay ratio of the fluorescence intensity at 540 nm and other wavelength was in good agreement with that with bulk sample. The total amount of the intensity of glass-wool per unit area at $$>$$ 350 nm was 23 times larger than that of chrysotile, corresponding to that with bulk sample. A practical microscopic method used to discriminate asbestos by combining the decay ratio and total amount of the intensity are proposed.

Journal Articles

QA/QC activities and estimation of uncertainty for ultra-trace analysis of uranium and plutonium in safeguards environmental samples

Usuda, Shigekazu*; Magara, Masaaki; Esaka, Fumitaka; Yasuda, Kenichiro; Kokubu, Yoko; Lee, C. G.; Miyamoto, Yutaka; Suzuki, Daisuke; Inagawa, Jun; Sakurai, Satoshi; et al.

Journal of Nuclear and Radiochemical Sciences, 11(2), p.A5 - A9, 2011/01

In the analysis of IAEA safeguards environmental samples, isotope ratios of ultra-trace amounts of uranium and plutonium in samples taken from nuclear facilities are determined to detect undeclared nuclear materials and activities. In order to keep and enhance the reliability of the measurement results, validation of analytical methods and estimation of measurement uncertainty in such ultra-trace analysis should be properly done in accordance with worldwide standards. In this paper, the current activities on achievement of QA/QC (quality assurance and quality control) and estimation of measurement uncertainty in the ultra-trace analysis at a clean chemistry laboratory (CLEAR) of JAEA are reported.

Journal Articles

Sequential separation of U, Th, Pb and lanthanides with a single anion-exchange column

Miyamoto, Yutaka; Yasuda, Kenichiro; Magara, Masaaki; Kimura, Takaumi; Usuda, Shigekazu*

Journal of Nuclear and Radiochemical Sciences, 10(2), p.7 - 12, 2009/12

With combination of a single anion-exchange column and mixed-media of CH$$_{3}$$COOH and other acids (HCl and/or HNO$$_{3}$$), 50 ng of U, Th, Pb, and lanthanides were sequentially separated. All of the elements were recovered more than 95%, and the decontamination factor was more than 100. This separation technique reduces separation time and simplified the complicated traditional processes without any special reagents and equipments.

Journal Articles

Feasibility study on identification of asbestos using laser-induced fluorescence

Ozu, Akira; Esaka, Fumitaka; Yasuda, Kenichiro

Bunseki Kagaku, 58(6), p.569 - 576, 2009/06

 Percentile:100(Chemistry, Analytical)

Laser-induced fluorescence of asbestos and several kinds of building materials such as glass-wools and talc, etc., have been studied for discriminating asbestos from the other materials. The fluorescence spectrums excited by ultra-violet (266 nm) laser pulse were observed over the wavelength range 350 to 700 nm, and the difference of the spectrum in shape between asbestos and the other materials was identified. The lifetime and relative intensity of the fluorescence emitted from those materials were also investigated and evaluated for the numerical discrimination of asbestos. Novel methods are presented for discriminating asbestos by comparing the relative ratio of the fluorescence intensity between two different ranges (430 and 575 nm) of the wavelength, and/or the lifetime and the total amount of the fluorescence. Applications of the method to conventional particle measurement systems, as examples, a microscopic method and an optical particle counter, are discussed.

115 (Records 1-20 displayed on this page)