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Battulga, B.; Atarashi-Andoh, Mariko; Nakanishi, Takahiro; Koarashi, Jun
Science of the Total Environment, 849, p.157758_1 - 157758_11, 2022/11
Times Cited Count:3 Percentile:43.07(Environmental Sciences)Characterizing plastic-associated biofilms is key to the better understanding of organic material and mineral cycling in the "Plastisphere"-the thin layer of microbial life on plastics. In this study, we propose a new method to extract biofilms from environmental plastics, in order to evaluate the properties of biofilm-derived organic matter through stable carbon (C) and nitrogen (N) isotope signatures and their interactions with radionuclides especially radiocesium (Cs). After ultrasound-assisted separation from the plastics, biofilm samples were successfully collected via a sequence of syringe treatments. Biofilm-derived organic matter samples (14.5-65.4 mg) from four river mouths in Japan showed Cs activity concentrations of 75 to 820 Bq kg biofilm (dw), providing evidence that environmental plastics, mediated by developed biofilms, serve as a carrier for Cs in the coastal environment. Significant differences in the (C and N signatures were also obtained for the biofilms, indicating the different sources, pathways, and development processes of biofilms on plastics.
Idomura, Yasuhiro
Europhysics Conference Abstracts (Internet), 45A, 4 Pages, 2021/06
This work presents the impacts of the hydrogen isotope mass and the normalized plasma size on confinement of hydrogen (H) and deuterium (D) plasmas dominated by ion temperature gradient driven turbulence. Numerical experiments of H and D plasmas with ion and electron heating conditions were conducted using the Gyrokinetic Toroidal 5D full- f Eulerian code GT5D. The energy confinement time in the ion heated numerical experiments was almost independent of isotope mass, and the energy confinement was determined mainly by the normalized plasma size or the plasma size divided by the ion gyro radius, indicating an impact of non-local transport. On the other hand, the electron heated numerical experiments showed a clear isotope mass dependency. In addition to the plasma size effect, the isotope mass dependency of the collisional energy transfer from electrons to ions changes the ion heat flux and the turbulence intensity, leading to the degradation of confinement in H plasmas. These results qualitatively agree with the hydrogen isotope scaling in experiments.
Department of Research Reactor and Tandem Accelerator
JAEA-Review 2020-074, 105 Pages, 2021/03
The Department of Research Reactor and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3 (Japan Research Reactor No.3), JRR-4 (Japan Research Reactor No.4), NSRR (Nuclear Safety Research Reactor), Tandem Accelerator, RI Production Facility and TPL (Tritium Process Laboratory). This annual report describes the activities of our department in fiscal year of 2018. We carried out the operation and maintenance, utilization, upgrading of utilization techniques, safety administration and international cooperation. Also contained are lists of publications, meetings, granted permissions on laws and regulations concerning atomic energy, outcomes in service and technical developments and so on.
Department of Research Reactor and Tandem Accelerator
JAEA-Review 2020-073, 113 Pages, 2021/03
The Department of Research Reactor and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3 (Japan Research Reactor No.3), JRR-4 (Japan Research Reactor No.4), NSRR (Nuclear Safety Research Reactor), Tandem Accelerator, RI Production Facility and Tritium Process Laboratory. This annual report describes the activities of our department in fiscal year of 2017. We carried out the operation and maintenance, utilization, upgrading of utilization techniques, safety administration and international cooperation. Also contained are lists of publications, meetings, granted permissions on laws and regulations concerning atomic energy, outcomes in service and technical developments and so on.
Department of Research Reactor and Tandem Accelerator
JAEA-Review 2020-072, 102 Pages, 2021/03
The Department of Research Reactor and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3 (Japan Research Reactor No.3), JRR-4 (Japan Research Reactor No.4), NSRR (Nuclear Safety Research Reactor), Tandem Accelerator, RI Production Facility and Tritium Process Laboratory). This annual report describes the activities of our department in fiscal year of 2016. We carried out the operation and maintenance, utilization, upgrading of utilization techniques, safety administration and international cooperation. Also contained are lists of publications, meetings, granted permissions on laws and regulations concerning atomic energy, outcomes in service and technical developments and so on.
Collaborative Laboratories for Advanced Decommissioning Science; Ibaraki University*
JAEA-Review 2019-041, 71 Pages, 2020/03
JAEA/CLADS, has been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") since FY2018. The Project aims at solving problems in nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. For this purpose, intelligence has been collected from all over the world, and basic research and human resource development have been promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. Among the adopted proposals in FY2018, this report summarizes the research results of the "Contribution to Risk Reduction in Decommissioning Works by the Elucidation of Basic Property of Radioactive Microparticles". In order to establish the decommissioning procedures (recovery of the melted fuels, decontamination inside the reactors, ensuring the safety of the workers, etc.) of the Fukushima Daiichi Nuclear Power Station, radioactive microparticles released by the accident are an important information source for clarifying what had happened inside the reactors in the course of the accident. The purpose of the present study is to obtain detailed knowledge on the basic properties (particle size, composition, electrical/optical properties, etc.) of the radioactive microparticles, as well as to further elucidate the various properties of the radioactive microparticles including the quantitative evaluation of alpha-ray-emitters, through the Japan-UK synergetic research. Thus, we are conducting research and development that will contribute to the comprehensive works towards the risk reduction in the "decommissioning" plan.
Miyakawa, Kazuya; Ishii, Eiichi; Hirota, Akinari*; Komatsu, Daisuke*; Ikeya, Kosuke*; Tsunogai, Urumu*
Applied Geochemistry, 76, p.218 - 231, 2017/01
Times Cited Count:18 Percentile:62.15(Geochemistry & Geophysics)no abstracts in English
Yokoyama, Keiichi; Matsuoka, Leo*
Nihon Genshiryoku Gakkai-Shi ATOMO, 56(8), p.525 - 528, 2014/08
With respect to the isotope separation of cesium, one of the long-lived fission products, the background, principle, feasibility, and research activity in Kansai Photon Science Institute are described.
Iwamoto, Osamu; Herman, M.*; Mughabghab, S. F.*; Oblozinsk, P.*; Trkov, A.*
AIP Conference Proceedings 769, p.434 - 437, 2005/05
Entirely new evaluations for all the Ge isotopes, from thermal energy to 20 MeV, has been performed with focus on photon production. In the resonance region, parameters were improved considerably compared to earlier evaluations. In the fast region, code EMPIRE-2.19 was used. Validation was done against photon data on Fe and Nb. Isotopic evaluations for Ge were summed up and compared with available measurements on natural Ge. Various quantities related to photon production, showing strong dependence on neutron incident energy, are discussed.
Yokoyama, Atsushi; Oba, Hironori; Hashimoto, Masashi; Katsumata, Keiichi; Akagi, Hiroshi; Ishii, Takeshi*; Oya, Akio*; Arai, Shigeyoshi*
Applied Physics B, 79(7), p.883 - 889, 2004/11
Times Cited Count:9 Percentile:42.05(Optics)Silicon isotope separation has been done utilizing the Infrared Multiphoton Dissociation of SiF irradiated with two-frequency CO laser lights. The two-frequency excitation method improved the separation efficiency with keeping the high enrichment factors. For example, SiF with the Si fraction of 99.4 % was obtained at 40.0 % dissociation of SiF after the simultaneous irradiation of 100 pulses with 966.23 cm photons (0.089 J/cm) and 954.55 cm photons (0.92 J/cm), while 1000 pulses were needed to obtain 99.0 % of Si at 27.2 % dissociation in the case of single frequency irradiation at 954.55 cm (0.92 J/cm). The single-step enrichment factors of Si and Si increased with increasing SiF pressure. The reason for this enhancement has been discussed in terms of the rotational and vibrational relaxations by collisions with ambient gases.
Tanigawa, Hisashi; Tanaka, Satoru*; Enoeda, Mikio; Akiba, Masato
Journal of Nuclear Materials, 329-333(2), p.1291 - 1294, 2004/08
Times Cited Count:4 Percentile:29.26(Materials Science, Multidisciplinary)In order to elucidate the interaction of hydrogen isotopes with irradiation defects, infrared absorption spectroscopy was conducted for a single crystal of LiO. Using FT-IR, O-D stretching vibration from the bulk LiO was observed under deutron irradiation. Under and after the irradiation, several peaks were observed in the O-D stretching vibration region and these peaks had different dependence on conditions of the irradiation. From the observed behaviour of the peaks, it was suggested that most of the irradiated deutron existed in LiO without O-D bonding because of interaction with the defects.
Yokoyama, Atsushi; Oba, Hironori; Shibata, Takemasa; Kawanishi, Shunichi*; Sugimoto, Shunichi*; Ishii, Takeshi*; Oya, Akio*; Miyamoto, Yoshiki*; Isomura, Shohei*; Arai, Shigeyoshi*
Journal of Nuclear Science and Technology, 39(4), p.457 - 462, 2002/04
Times Cited Count:2 Percentile:17.03(Nuclear Science & Technology)no abstracts in English
Mori, Satoshi*; Nakanishi, Tomoko*; Hayashi, Hiroaki*; Oyama, Takuji*; Uchida, Hiroshi*; Matsuhashi, Shimpei; Sekine, Toshiaki
Radioisotopes, 50(9), p.408 - 418, 2001/09
no abstracts in English
Sekine, Toshiaki
Nihon Dojo Hiryo Gaku Zasshi, 71(6), p.928 - 929, 2000/11
no abstracts in English
Committee for the Joint Research Project on the Advanced Radiation Technology; Committee for the Collaborative Research on the Advanced Radiation Technology
JAERI-Conf 2000-008, 113 Pages, 2000/06
no abstracts in English
Tomimitsu, Hiroshi; *; Aizawa, Kazuya; Kikuta, Seishi*
Nuclear Instruments and Methods in Physics Research A, 420(3), p.453 - 466, 1999/00
Times Cited Count:2 Percentile:27.57(Instruments & Instrumentation)no abstracts in English
Sugita, Michiaki; *; Furuno, Kohei*
Physics Letters B, 440(3-4), p.239 - 245, 1998/00
Times Cited Count:6 Percentile:39.16(Astronomy & Astrophysics)no abstracts in English
Togawa, Orihiko
JAERI-Data/Code 95-009, 35 Pages, 1995/07
no abstracts in English
Osa, Akihiko; Asai, Masato*; Koizumi, Mitsuo; Sekine, Toshiaki; ; *; Yamamoto, Hiroshi*; Kawade, Kiyoshi*
Nuclear Physics A, 588, p.185C - 190C, 1995/00
Times Cited Count:24 Percentile:76.81(Physics, Nuclear)no abstracts in English
JAERI-Conf 94-004, 187 Pages, 1994/11
no abstracts in English