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Journal Articles

Measurement method for $$^{134}$$Cs in environment by use of the coincidence method

Hirade, Tetsuya; Katayama, Atsushi; Masaki, Nobuyuki

Radioisotopes, 64(5), p.311 - 318, 2015/05

The quantity of Cesium radioisotopes is estimated with full absorption peaks on the energy spectra measured by $$gamma$$-ray detectors such as Ge semiconductor detector. The heavy shield box made of Lead is needed to obtain reliable data, because the detection efficiency is in inverse proportion to square of the distance between the detectors and the radioactive materials. We have noticed that $$^{134}$$Cs emits two $$gamma$$-rays, 605 keV and 796 keV, with high efficiency, and that there are almost no radio isotopes which emit two $$gamma$$-rays as $$^{134}$$Cs does in environment. In the case of coincidence measurements of two $$gamma$$-rays, the detection efficiency is in inverse proportion to the fourth power of the distance between the detectors and the radioactive materials. Therefore the contamination with radioisotopes around the detectors do not affect to the count of the coincidence events. Hence, it is possible to estimate the quantity of $$^{134}$$Cs by in-situ and nondestructive measurement.

Journal Articles

Fundamental welding R&D results for manufacturing vacuum vessel of JT-60SA

Asano, Shiro*; Okuyama, Toshihisa*; Onawa, Toshio*; Yanagi, Yutaka*; Ejiri, Mitsuru*; Kanahara, Toshio*; Ichihashi, Koji*; Kikuchi, Atsushi*; Mizumaki, Shoichi*; Masaki, Kei; et al.

Fusion Engineering and Design, 86(9-11), p.1816 - 1820, 2011/10

 Times Cited Count:10 Percentile:32.18(Nuclear Science & Technology)

The real vacuum vessel (VV) manufacturing of JT-60SA has started since Nov. 2009 at Toshiba. Prior to starting manufacturing, fundamental welding R&Ds had been performed by three stages. In the first stage, primary tests for screening welding method were performed. In the second stage, the trial welding for 1m-long straight and curved double shell samples were conducted. The dependences of welding quality and distortion on the welding conditions, such as arc voltage and current, setting accuracy, welding sequence, the shape of grooves, etc. were measured. In addition, welding condition with low heat input was explored. In the last stage, fabrication sequence was confirmed and established by the trial manufacturing of the 20$$^{circ}$$ upper half mock-up. This poster presents the R&D results obtained in the first and second stages.

Journal Articles

Systematic analysis method for radioactive wastes generated from nuclear research facilities

Kameo, Yutaka; Ishimori, Kenichiro; Haraga, Tomoko; Shimada, Asako; Katayama, Atsushi; Nakashima, Mikio*; Takahashi, Kuniaki

Nippon Genshiryoku Gakkai Wabun Rombunshi, 10(3), p.216 - 225, 2011/09

Analytical methods have been developed for simple and rapid determination of radioactive nuclides, which are selected as important nuclides for safety assessment of disposal of wastes generated from research facilities. We advanced the development of a high-efficiency non-destructive measurement technique for $$gamma$$-ray emitting nuclides, simple and rapid methods for pretreatment of hard-to dissolve samples and subsequent radiochemical separations, and rapid determination methods for long-lived nuclides. In order to establish a system to analyze the important nuclides in various kinds of samples, actual radioactive wastes such as concentrated liquid waste, activated concrete, and metal pipes, were analyzed by the present method. The results showed that the present method was well suited for a rapid and simple determination of low-level radioactive wastes generated from research facilities.

Journal Articles

Metamagnetic behavior in heavy-fermion compound YbIr$$_2$$Zn$$_{20}$$

Takeuchi, Tetsuya*; Yasui, Shinichi*; Toda, Masatoshi*; Matsushita, Masaki*; Yoshiuchi, Shingo*; Oya, Masahiro*; Katayama, Keisuke*; Hirose, Yusuke*; Yoshitani, Naohisa*; Honda, Fuminori*; et al.

Journal of the Physical Society of Japan, 79(6), p.064609_1 - 064609_15, 2010/06

 Times Cited Count:37 Percentile:15.57(Physics, Multidisciplinary)

Journal Articles

Low-temperature magnetic orderings and Fermi surface properties of LaCd$$_{11}$$, CeCd$$_{11}$$, and PrCd$$_{11}$$ with a caged crystal structure

Yoshiuchi, Shingo*; Takeuchi, Tetsuya*; Oya, Masahiro*; Katayama, Keisuke*; Matsushita, Masaki*; Yoshitani, Naohisa*; Nishimura, Naoto*; Ota, Hisashi*; Tateiwa, Naoyuki; Yamamoto, Etsuji; et al.

Journal of the Physical Society of Japan, 79(4), p.044601_1 - 044601_11, 2010/04

 Times Cited Count:11 Percentile:39.04(Physics, Multidisciplinary)

JAEA Reports

Analysis of the radioactivity concentrations in asphalt- or cement-solidified products generated from research facilities

Hoshi, Akiko; Kameo, Yutaka; Katayama, Atsushi; Sakai, Akihiro; Tsuji, Tomoyuki; Nakashima, Mikio; Kihara, Shinji; Takahashi, Kuniaki

JAEA-Data/Code 2009-023, 84 Pages, 2010/03

JAEA-Data-Code-2009-023.pdf:12.81MB

In order to establish the practical evaluation methods such as scaling factor method to determine the radioactivity concentrations of the important nuclides for safety assessment of disposal of radioactive wastes, we analyzed low-level radioactive liquid waste (56 samples), which is generated from various research facilities at Nuclear Science Research Institute from FY1998 to FY2007 and accumulated the radioactivity concentrations data (563 data) of the 17 important nuclides. We investigated the correlation of the radioactivity concentrations of the important nuclides with the "Key nuclides ($$^{60}$$Co or $$^{137}$$Cs)". In present paper, the radioactivity concentrations data of the 17 important nuclides and the results of the correlation of the radioactivity concentrations are summarized for the data to establish the practical evaluation methods to determine the radioactivity concentrations in asphalt-solidified or cement-solidified products.

Journal Articles

Simple determination of $$^{99}$$Tc in radioactive waste using Tc extraction disk and imaging plates

Kameo, Yutaka; Katayama, Atsushi; Hoshi, Akiko; Haraga, Tomoko; Nakashima, Mikio

Applied Radiation and Isotopes, 68(1), p.139 - 143, 2010/01

 Times Cited Count:8 Percentile:45.28(Chemistry, Inorganic & Nuclear)

A simple method was developed for determination of $$^{99}$$Tc in low-level radioactive waste: Technetium-99 retained by a solid phase extraction disk was directly measured with imaging plates system. It was found that more than 97% of Tc were retained by the disk from a solution of pH 2 to 12, whereas depth profile of Tc in the disk, which greatly influences the counting efficiency, depended on solution pH. The present method was successfully applied to actual radioactive liquid waste samples arising from nuclear research facilities.

Journal Articles

Heavy fermion state in YbIr$$_2$$Zn$$_{20}$$

Yoshiuchi, Shingo*; Toda, Masatoshi*; Matsushita, Masaki*; Yasui, Shinichi*; Hirose, Yusuke*; Oya, Masahiro*; Katayama, Keisuke*; Honda, Fuminori*; Sugiyama, Kiyohiro*; Hagiwara, Masayuki*; et al.

Journal of the Physical Society of Japan, 78(12), p.123711_1 - 123711_4, 2009/12

 Times Cited Count:37 Percentile:15.73(Physics, Multidisciplinary)

JAEA Reports

Simple and rapid determination methods for low-level radioactive wastes generated from nuclear research facilities (Guidelines for determination of radioactive waste samples)

Kameo, Yutaka; Shimada, Asako; Ishimori, Kenichiro; Haraga, Tomoko; Katayama, Atsushi; Hoshi, Akiko; Nakashima, Mikio

JAEA-Technology 2009-051, 81 Pages, 2009/10

JAEA-Technology-2009-051.pdf:3.6MB

Simple and rapid determination methods were developed for an evaluation of important nuclides, U, and Th in wastes generated from research facilities at Nuclear Science Research Institute and Oarai Research and Development Center. The present methods were assumed to apply to solidified products made from miscellaneous wastes by plasma melting at the Advanced Volume Reduction Facilities. In order to reduce costs of radiochemical analysis and to establish a routine analytical system, counting efficiency of non-destructive $$gamma$$-ray measurements was improved, and times for pretreatment of solidified product samples and subsequent radiochemical separations were shortened. In addition to this, rapid and high sensitive detection methods were developed for a determination of long-lived nuclides. The present paper describes guidelines for the determination of radionuclides in the low-level radioactive wastes by using the present simple and rapid methods.

Journal Articles

Analytical method for $$^{59}$$Ni and $$^{63}$$Ni in low-level radioactive wastes arising from nuclear research facilities

Kameo, Yutaka; Haraga, Tomoko; Katayama, Atsushi; Hoshi, Akiko; Nakashima, Mikio

Radioisotopes, 58(5), p.153 - 160, 2009/05

A routine analytical method was developed for the determination of $$^{59}$$Ni and $$^{63}$$Ni in low-level radioactive wastes arising from nuclear research facilities. A separation scheme of $$^{59}$$Ni and $$^{63}$$Ni in waste samples was optimized by considering concentration of interference radionuclides and chemical composition of the waste samples. Concentrations of $$^{59}$$Ni and $$^{63}$$Ni in actual radioactive wastes such as pipes and liquid waste could be well determined by the present analytical method. In the determination, the time required for the chemical separation was five to seven days per ten samples. It was concluded that the present method could be applied to a routine determination of $$^{59}$$Ni and $$^{63}$$Ni in low-level radioactive wastes. In the present experiment, radioactivity ratio of $$^{63}$$Ni/$$^{59}$$Ni in pipe samples, which were taken from a nuclear research reactor, was estimated by a computer code (ORIGEN2). Radioactivity ratio of $$^{63}$$Ni/$$^{59}$$Ni, obtained by the computer calculation, was ranged from 98 to 109 and that obtained by the present analytical method was 118 $$pm$$ 6.

Journal Articles

Time-of-flight mass spectrometer using an imaging detector and a rotating electric field

Katayama, Atsushi; Kameo, Yutaka; Nakashima, Mikio

Shitsuryo Bunseki, 56(5), p.229 - 234, 2008/10

A new technique is described for minor isotope analysis by using a rotating electric field and an imaging detector. The rotating electric field is generated by cylindrically arranged six plane electrodes with multi-phase sinusoidal wave voltage. When ion packets that are discriminated by time-of-flight enter the rotating electric field, these are circularly deflected and make a spiral image on fluorescent screen of detector. This spiral image represents m/z values data as position of ions and abundance of ions as brightness. For minor isotopes analysis, the micro channel plate detector is used under gate control operation to remove from influence of high intensity of major isotopes.

Journal Articles

A Study of new preparation method for AMS targets

Katayama, Atsushi; Kameo, Yutaka; Nakashima, Mikio; Matsuzaki, Hiroyuki*

Dai-10-Kai AMS Shimpojiumu Hokokushu, p.234 - 237, 2008/00

The determination of $$^{129}$$I by accelerator mass spectrometry (AMS) has generally been used measurement targets from AgI precipitation. For more sensitive determination of $$^{129}$$I, it is necessary to reduce the quantity of iodine carrier for precipitation. But, more than 1mg is the amount of carrier stable iodine needed at present to make a reliable sample treatment and AMS determination. In this study, we examined the basics of procedures of the direct measurement target that used adsorption reaction of the molecular iodine to the metal silver surface in substitution for precipitation. Using this procedure, we have prepared measurement targets with a carrier from 1 to 0.2 mg iodine.

Journal Articles

Analysis of $$^{129}$$I in radioactive wastes by accelerator mass spectrometry

Katayama, Atsushi; Kameo, Yutaka; Nakashima, Mikio

Radioisotopes, 56(12), p.787 - 793, 2007/12

Determination of the concentration of $$^{129}$$I in radioactive wastes is important according to waste management and environmental concern. In the present work, accelerator mass spectrometry (AMS) was applied to measurement of $$^{129}$$I/$$^{127}$$I ratio to determine $$^{129}$$I concentration in radioactive waste. Solid-phase extraction disks (Anion-SR) for chemical separation of iodine from radioactive waste samples were used to prepare AMS targets. This method made it possible to swiftly separate iodide ions from sample solutions, compared with a conventional liquid-liquid extraction method. Considering contamination of a sample with $$^{129}$$I from a work site environment, we derived the suitable amount of the $$^{127}$$I carrier to keep the background value of the $$^{129}$$I/$$^{127}$$I ratio as low as possible. The present method was successfully applied to laboratory standards and liquid waste samples arising from nuclear facilities in Japan Atomic Energy Agency.

Journal Articles

Rapid determination of $$^{89}$$Sr and $$^{90}$$Sr in radioactive waste using Sr extraction disk and beta-ray spectrometer

Kameo, Yutaka; Katayama, Atsushi; Fujiwara, Asako; Haraga, Tomoko; Nakashima, Mikio

Journal of Radioanalytical and Nuclear Chemistry, 274(1), p.71 - 78, 2007/10

 Times Cited Count:16 Percentile:24.25(Chemistry, Analytical)

no abstracts in English

Journal Articles

Analysis of tritium of clearance level in concrete

Fujiwara, Asako; Kameo, Yutaka; Katayama, Atsushi; Nakashima, Mikio

Nippon Genshiryoku Gakkai Wabun Rombunshi, 6(1), p.58 - 64, 2007/03

no abstracts in English

Journal Articles

Ion beam breeding of rice variety suitable for low nitrogen input

Katayama, Hisato*; Kitamura, Harushige*; Mori, Mari*; Nakagawa, Junya*; Yoshida, Takahiro*; Kawai, Toshihiko*; Hase, Yoshihiro; Tanaka, Atsushi

JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 94, 2007/02

no abstracts in English

Journal Articles

JAEA-AMS iodine-129 project

Suzuki, Takashi; Katayama, Atsushi; Amano, Hikaru

Dai-9-Kai AMS Shimpojiumu Hokokushu, P. 20, 2006/10

no abstracts in English

Journal Articles

Photoemission and core-level absorption spectroscopy of Fe$$_{x}$$NbS$$_{2}$$

Saito, Yuji; Kobayashi, Keisuke*; Fujimori, Atsushi; Yamamura, Yasuhisa*; Koyano, Mikio*; Tsuji, Toshihide*; Katayama, Shinichi*

Journal of Electron Spectroscopy and Related Phenomena, 144-147, p.829 - 832, 2005/06

 Times Cited Count:3 Percentile:81.51(Spectroscopy)

no abstracts in English

Journal Articles

Introduction of imaging detection into a time-of-flight mass spectrometer to improve the dynamic range in the isotope ratio measurement

Katayama, Atsushi; Furukawa, Katsutoshi; Watanabe, Kazuo

Bunseki Kagaku, 52(6), p.461 - 467, 2003/06

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

An imaging ion detection system was introduced to a time-of-flight mass spectrometer (TOFMS) in order to increase dynamic range in the isotope ratio measurements. The new detection system utilizes a position sensitive micro channel plate (MCP) with a phosphor plate and a CCD camera which records light spots on the MCP. Mass discriminated ion beams produced by laser resonance ionization were swept on the surface of MCP by a time-depended electric field located in front of the MCP. The resulting light spots were recorded as images by CCD camera. A mass spectrum was obtained from the images. The present method was applied to the isotope analysis of calcium. A dynamic range of more than 5 orders of magnitude was achieved.

Oral presentation

Applied studies of $$^{129}$$I using AMS at JAEA-Mutsu

Suzuki, Takashi; Kitamura, Toshikatsu; Kabuto, Shoji; Isogai, Keisuke*; Bamba, Shigeru*; Katayama, Atsushi; Kameo, Yutaka; Kuwabara, Jun; Sakamoto, Shinya*; Togawa, Orihiko; et al.

no journal, , 

no abstracts in English

50 (Records 1-20 displayed on this page)