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Journal Articles

Temporal change in radiological environments on land after the Fukushima Daiichi Nuclear Power Plant accident

Saito, Kimiaki; Mikami, Satoshi; Ando, Masaki; Matsuda, Norihiro; Kinase, Sakae; Tsuda, Shuichi; Sato, Tetsuro*; Seki, Akiyuki; Sanada, Yukihisa; Wainwright-Murakami, Haruko*; et al.

Journal of Radiation Protection and Research, 44(4), p.128 - 148, 2019/12

Journal Articles

Measurement of air dose rates over a wide area around the Fukushima Dai-ichi Nuclear Power Plant through a series of car-borne surveys

Ando, Masaki; Nakahara, Yukio; Tsuda, Shuichi; Yoshida, Tadayoshi; Matsuda, Norihiro; Takahashi, Fumiaki; Mikami, Satoshi; Kinouchi, Nobuyuki; Sato, Tetsuro*; Tanigaki, Minoru*; et al.

Journal of Environmental Radioactivity, 139, p.266 - 280, 2015/01

 Times Cited Count:43 Percentile:86.58(Environmental Sciences)

A series of car-borne surveys using the KURAMA and KURAMA-II systems was conducted in a wide area in eastern Japan from June 2011 to December 2012 to evaluate the distribution of air dose rates around the Fukushima Dai-ichi Nuclear Power Plant, and to determine the time-dependent trend of decrease in air dose rates. An automated data processing system was established, which enables analyses of large amounts of data obtained with the use of about 100 units of the measurement system in a short time. The initial data for studying the migration status of radioactive cesium was obtained in the first survey, followed by the other car-borne surveys having wider measurement ranges. Comparing the measured air dose rates obtained in each survey, it was found that the decreasing trend of air dose rates measured through car-borne surveys was larger than that expected from the physical decay of radioactive cesium and that measured using NaI (Tl) survey meters around the road.

Journal Articles

Maintenance activities in chemical processing facility, 1; Renewal of driving unit of negative pressure control valves

Kobayashi, Yuki; Takahashi, Tetsuro; Shinozaki, Tadahiro; Ogasawara, Koji; Koizumi, Kenji; Nakajima, Yasuo

Nihon Hozen Gakkai Dai-7-Kai Gakujutsu Koenkai Yoshishu, p.161 - 166, 2010/07

The negative pressure control valve is reliable apparatus which has been used in many nuclear facilities. In recent years, there are some troubles on those valves in CPF (Chemical Reprocessing Facility) by the aged deterioration because the valves were kept using for more than 25 years after facility had operated. Therefore, we have been carrying out renewal of driving units of the valves to assure performance of negative pressure control function and to keep stability of operation of the facility. In this presentation, we report knowledge provided through the renewal work, such as the renewal procedure, the deterioration situation of components and the cause of troubles.

Journal Articles

In-beam $$gamma$$-ray spectroscopy of $$^{248,250,252}$$Cf by neutron-transfer reactions using a Cf target

Takahashi, Ryuta; Ishii, Tetsuro; Asai, Masato; Nagae, Daisuke*; Makii, Hiroyuki; Tsukada, Kazuaki; Toyoshima, Atsushi; Ishii, Yasuo; Matsuda, Makoto; Makishima, Akiyasu*; et al.

Physical Review C, 81(5), p.057303_1 - 057303_4, 2010/05

 Times Cited Count:12 Percentile:64.15(Physics, Nuclear)

The ground-state bands of $$^{248,250,252}$$Cf have been established up to 10$$^{+}$$, 12$$^{+}$$, and 10$$^{+}$$ states, respectively, by in-beam $$gamma$$-ray spectroscopy using neutron-transfer reactions with a $$^{18}$$O beam and a highly radioactive Cf target. The deexcitation $$gamma$$ rays in $$^{248,250,252}$$Cf were identified by taking coincidences with outgoing particles of $$^{16-19}$$O measured with Si $$Delta E$$-$$E$$ detectors, and by selecting their kinetic energies. This is the first in-beam $$gamma$$-ray spectroscopy for Cf isotopes.

Journal Articles

Lifetime measurements for the first 2$$^{+}$$ states in $$^{162,164}$$Gd populated by the $$beta$$ decay of $$^{162,164}$$Eu

Nagae, Daisuke*; Ishii, Tetsuro; Takahashi, Ryuta*; Asai, Masato; Makii, Hiroyuki; Osa, Akihiko; Sato, Tetsuya; Ichikawa, Shinichi; Shimizu, Yoshifumi*; Shoji, Takuya*

AIP Conference Proceedings 1224, p.156 - 160, 2010/04

 Times Cited Count:2 Percentile:65.93

JAEA Reports

Research and development for treatment and disposal technologies of TRU waste; JFY 2007 annual report

Kamei, Gento; Honda, Akira; Mihara, Morihiro; Oda, Chie; Murakami, Hiroshi; Masuda, Kenta; Yamaguchi, Kohei; Matsuda, Setsuro; Ichige, Satoru; Takahashi, Kuniaki; et al.

JAEA-Research 2008-082, 84 Pages, 2008/11

JAEA-Research-2008-082.pdf:2.52MB
JAEA-Research-2008-082(errata).pdf:0.15MB

Based on Japanese governmental policy and general scheme, research and development of geological disposal technology for TRU waste has been proceeding to improve reliability of the safety assessment of the co-locational disposal of TRU waste and of HLW, to expand the basement of generic safety assessment, and to develop the alternative technology to cope with the broad geologic environment of Japan. Japan Atomic Energy Agency is dealing with the assignments in the governmental generic scheme. We report here the progress of the studies at the end of H19 (2007) fiscal year, which are (1) treatment and packaging of TRU waste including applicability of calcination for unpacking and sorting of wastes, characterization and inspection methodology of TRU waste, (2) mechanical assessment for the near-field structure including model development and preparation, introduction of hostrock creep model and coupling analysis of deformation of hostrock and engineered barrier. (3) performance assessment of the disposal system including data acquisition and preparation on radionuclides migration, cementitious material alteration, bentonite and hostrock alteration with alkaline solution and nitrate effect, and (4) alternative technology development including decomposition of nitrate.

Journal Articles

Investigation of Radioactive Inventory in the TRU Solid Wastes Generated from the Tokai Reprocessing Plant

Sakakibara, Tetsuro; Tsutomu, Tanabe,; Takahashi, Kuniaki; Akutsu, Shigeru; Kojima, Hiroshi; Sakashita, Akira*; Kuroda, Kazuhiko*

Proceedings of International Waste Management Symposium 2005 (WM 2005), 0 Pages, 2005/00

Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.

Journal Articles

Acoustic emission and disturbances in central solenoid model coil for international thermonuclear experimental reactor

Arai, K.*; Ninomiya, Akira*; Ishigooka, Takeshi*; Takano, Katsutoshi*; Nakajima, Hideo; Michael, P.*; Vieira, R.*; Martovetsky, N.*; Sborchia, C.*; Alekseev, A.*; et al.

Cryogenics, 44(1), p.15 - 27, 2004/01

 Times Cited Count:3 Percentile:16.14(Thermodynamics)

no abstracts in English

Journal Articles

Beamline for surface and interface structures at SPring-8

Sakata, Osami*; Furukawa, Yukito*; Goto, Shunji*; Mochizuki, Tetsuro*; Uruga, Tomoya*; Takeshita, Kunikazu*; Ohashi, Haruhiko*; Ohata, Toru*; Matsushita, Tomohiro*; Takahashi, Sunao*; et al.

Surface Review and Letters, 10(2&3), p.543 - 547, 2003/04

 Times Cited Count:127 Percentile:96.2(Chemistry, Physical)

The main components of a new beamline for surface and interface crystal structure determination at SPring-8 are briefly described. Stages for the beamline monochromator are modified for making an incident X-ray intensity more stable for surface X-ray experiments. Absolute photon flux densities were measured with an incident photon energy. A new ultrahigh vacuum system is introduced with preliminary X-ray measurements from an ordered oxygen on Pt(111) surface.

Oral presentation

Degradation of nitrate ion by reduction using precious metal catalyst, 4; Degradation of high concentration of nitrate ion by flow system degradation method

Kadowaki, Haruhiko; Kato, Atsushi; Tomioka, Osamu; Sakakibara, Tetsuro; Yamaguchi, Hiromi; Meguro, Yoshihiro; Takahashi, Kuniaki

no journal, , 

no abstracts in English

Oral presentation

Development of a linear ion trap at JAEA-ISOL

Nagae, Daisuke; Ishii, Tetsuro; Makii, Hiroyuki*; Takahashi, Ryuta

no journal, , 

Construction of a linear ion trap is now in progress at JAEA-ISOL. We trapped $$^{21}$$Na, $$^{92}$$Rb, and $$^{142}$$Cs ions successfully. We will talk about a development of the trap.

Oral presentation

Development of linear ion trap at JAEA

Nagae, Daisuke; Ishii, Tetsuro; Makii, Hiroyuki*; Takahashi, Ryuta; Ichikawa, Shinichi; Osa, Akihiko; Otokawa, Yoshinori

no journal, , 

no abstracts in English

Oral presentation

In-beam $$gamma$$-ray spectroscopy of $$^{248,250,252}$$Cf using neutron-transfer reactions

Takahashi, Ryuta; Ishii, Tetsuro; Nagae, Daisuke; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Ishii, Yasuo; Matsuda, Makoto; Shizuma, Toshiyuki; Makii, Hiroyuki*; et al.

no journal, , 

no abstracts in English

Oral presentation

$$alpha$$-$$gamma$$ coincidence spectroscopy of $$^{259}$$Rf using a mixed Cf target

Asai, Masato; Tsukada, Kazuaki; Kasamatsu, Yoshitaka*; Sato, Tetsuya; Toyoshima, Atsushi; Ishii, Yasuo; Takahashi, Ryuta; Nagame, Yuichiro; Ishii, Tetsuro; Nishinaka, Ichiro; et al.

no journal, , 

$$gamma$$ rays following the $$alpha$$ decay of $$^{259}$$Rf have been observed for the first time by means of $$alpha$$-$$gamma$$ coincidence spectroscopy. $$^{259}$$Rf was produced via the $$^{251}$$Cf($$^{12}$$C,4n)$$^{259}$$Rf reaction at the JAEA tandem accelerator. Two $$gamma$$ lines were observed at 97.3 and 146.7 keV in coincidence with the 8770 keV $$alpha$$ transition of $$^{259}$$Rf. The energy differences and intensities of these $$gamma$$ transitions, which are very similar to those in the $$alpha$$ decay of $$^{257}$$No with the same neutron number N = 155, allow us to assign the 3/2$$^{+}$$[622] configuration to the 146.7 keV level in $$^{255}$$No as well as to the ground state of $$^{259}$$Rf. This result indicates that the order of neutron orbitals should be inverted between $$^{255}$$Fm and $$^{257}$$No in $$N=155$$ isotones.

Oral presentation

Measurement of fission probability of the compound nucleus $$^{240}$$U$$^{*}$$ populated by the reaction $$^{238}$$U($$^{18}$$O,$$^{16}$$O)

Nishio, Katsuhisa; Nishinaka, Ichiro; Mitsuoka, Shinichi; Makii, Hiroyuki; Furutaka, Kazuyoshi; Wakabayashi, Yasuo; Takahashi, Ryuta; Ishii, Tetsuro; Chiba, Satoshi; Hirose, Kentaro*; et al.

no journal, , 

no abstracts in English

Oral presentation

Fission fragment mass distributions for actinide nuclei produced by nucleon transfer reaction

Nishio, Katsuhisa; Nishinaka, Ichiro; Mitsuoka, Shinichi; Makii, Hiroyuki; Furutaka, Kazuyoshi; Wakabayashi, Yasuo; Takahashi, Ryuta*; Ishii, Tetsuro; Chiba, Satoshi; Hirose, Kentaro*; et al.

no journal, , 

no abstracts in English

Oral presentation

Maintenance activities in Chemical Reprocessing Facility (CPF); Renewal of driving unit of negative pressure control valves

Kobayashi, Yuki; Takahashi, Tetsuro; Shinozaki, Tadahiro; Ogasawara, Koji; Koizumi, Kenji; Nakajima, Yasuo

no journal, , 

The negative pressure control valve is reliable apparatus which has been used in many nuclear facilities. In recent years, there are some troubles on those valves in CPF (Chemical Reprocessing Facility) by the aged deterioration because the valves were kept using for more than 25 years after facility had operated. Therefore, we have been carrying out renewal of driving units of the valves to assure performance of negative pressure control function and to keep stability of operation of the facility. In this presentation, we report knowledge provided through the renewal work, such as the renewal procedure, the deterioration situation of components and the cause of troubles.

Oral presentation

Alpha-decay spectroscopy of Rf and Lr isotopes

Asai, Masato; Haba, Hiromitsu*; Tsukada, Kazuaki; Sato, Nozomi; Kasamatsu, Yoshitaka*; Kaji, Daiya*; Morimoto, Koji*; Morita, Kosuke*; Sato, Tetsuya; Toyoshima, Atsushi; et al.

no journal, , 

Alpha-decay spectroscopy of odd-mass Rf and Lr isotopes was performed to establish proton and neutron single-particle orbitals. $$gamma$$ rays following the $$alpha$$ decay of $$^{259}$$Rf were observed for the first time through the $$alpha$$-$$gamma$$ coincidence measurement, and the neutron configuration of the ground state of $$^{259}$$Rf was assigned. It was found that the ground-state configuration of $$^{259}$$Rf is different from those of the lighter N = 155 isotones $$^{255}$$Fm and $$^{253}$$Cf. For the Lr isotopes, the proton configurations of the ground and isomeric states in $$^{255}$$Lr and the ground states of $$^{257}$$Lr and $$^{259}$$Lr were definitely identified through the high-resolution $$alpha$$ fine structure spectroscopy. Theoretical calculations based on the macroscopic-microscopic model revealed that the change of the ground-state configuration in the N = 155 isotones is strongly associated with the rapidly decreasing hexadecapole deformation with increasing atomic number.

Oral presentation

$$alpha$$-$$gamma$$ and high-resolution $$alpha$$ fine-structure spectroscopy for the heaviest nuclei

Asai, Masato; Haba, Hiromitsu*; Tsukada, Kazuaki; Sato, Nozomi; Kasamatsu, Yoshitaka*; Kaji, D.*; Morimoto, Koji*; Morita, Kosuke*; Sato, Tetsuya; Toyoshima, Atsushi; et al.

no journal, , 

Alpha-gamma and high-resolution $$alpha$$ fine-structure spectroscopy of Rf and Lr isotopes was performed to clarify the nuclear structure of superheavy nuclei. $$gamma$$ rays following the $$alpha$$ decay of $$^{259}$$Rf were observed for the first time through the $$alpha$$-$$gamma$$ coincidence measurement, and the neutron configuration of the ground state of $$^{259}$$Rf was assigned. It was found that the ground-state configuration of $$^{259}$$Rf is different from those of the lighter N = 155 isotones $$^{255}$$Fm and $$^{253}$$Cf. For the Lr isotopes, the proton configurations of the ground and isomeric states in $$^{255}$$Lr and the ground states of $$^{257}$$Lr and $$^{259}$$Lr were definitely identified through the high-resolution $$alpha$$ fine structure spectroscopy. Theoretical calculations based on the macroscopic-microscopic model revealed that the change of the ground-state configuration in the N = 155 isotones is strongly associated with the rapidly decreasing hexadecapole deformation with increasing atomic number.

Oral presentation

Beam-line improvement and new experiment stations of KEK-IMSS slow-positron facility

Wada, Ken*; Mochizuki, Izumi*; Hyodo, Toshio*; Kosuge, Takashi*; Saito, Yuki*; Shidara, Tetsuo*; Osawa, Satoshi*; Ikeda, Mitsuo*; Shirakawa, Akihiro*; Furukawa, Kazuro*; et al.

no journal, , 

no abstracts in English

25 (Records 1-20 displayed on this page)