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Yamamoto, Kazami
EPJ Web of Conferences, 153, p.07022_1 - 07022_6, 2017/09
Times Cited Count：1 Percentile：61.03(Nuclear Science & Technology)The J-PARC 3 GeV Rapid Cycling Synchrotron (RCS) delivers a 1-MW, high-intensity beam to the following facilities. In such high-intensity accelerator, the operational beam intensity is limited to keep the exposure to the workers by the residual dose within acceptable tolerances. Therefore we continue to commission the accelerator system to reduce the beam loss. In order to achieve further high-intensity operation, the J-PARC accelerator system was drastically upgraded (Increment of the injection energy of RCS and peak current of Linac) over the past two years. After the upgrade, the beam loss was decreased by the commissioning. The output power was increased; nevertheless the residual doses were kept same level or decreased. Since we replaced the broken collimator which was higher activated, we kept the exposure to the workers within acceptable level.
Fukushima Environmental Safety Center, Sector of Fukushima Research and Development
JAEA-Review 2014-051, 121 Pages, 2015/03
JAEA-Review-2014-051.pdf:64.45MB
The Japan Atomic Energy Agency (JAEA) was charged with conducting a range of "Decontamination Pilot Project" to examine the applicability of decontamination technologies. The project was implemented at 16 sites in 11 municipalities within the evacuated zone. Despite tight boundary conditions in terms of timescale and resources, the project provides a good basis for developing recommendations on how to assure decontamination efficiency and worker safety whilst additionally constraining costs, subsequent waste management and environmental impacts. This report, based on the Japanese detailed reports that have been published elsewhere, consists of two volumes. This volume 1 summarises the Decontamination Pilot Project, providing the background required to put this work in context for an international audience. In volume 2, the subsequent application of output from these projects to regional remediation now being conducted by the Japanese government and municipalities, is discussed, along with a status update on such work, an overview of associated JAEA's R&D and international input to/review of regional environmental decontamination in Fukushima.
Endo, Akira; Yamaguchi, Yasuhiro
Radiation Research, 159(4), p.535 - 542, 2003/04
Times Cited Count：14 Percentile：39.81(Biology)The first criticality accident in Japan occurred in a uranium processing plant in Tokai-mura in September, 1999. In this accident, two workers on the site were heterogeneously exposed to neutrons and 
rays produced by the nuclear fission. Heterogeneous exposure influenced the clinical course observed in the skin and organs of these workers. By request from medical groups, we attempted to clarify the dose distribution of the two heavily exposed workers with the aid of computer simulation, which is currently the only means by which to address this complicated problem. This paper presents elucidated skin dose distributions, depth dose distributions inside the trunk, and neutron-to- dose ratios.
Endo, Akira; Yamaguchi, Yasuhiro; Takahashi, Fumiaki
Radiation Risk Assessment Workshop Proceedings, p.151 - 156, 2003/00
We have developed a new system using numerical simulation technique for analyzing dose distribution in various postures by neutron, photon and electron exposures. The system consists of mathematical human phantoms with movable arms and legs and Monte Carlo codes MCNP and MCNPX. This system was applied to the analysis of dose distribution for the heavily exposed workers in the Tokai-mura criticality accident. The paper describes the simulation technique employed and a summary of the dose analysis.
Oshima, Soichiro; Sukegawa, Takenori; Shiraishi, Kunio; Yanagihara, Satoshi
JAERI-Tech 2001-086, 83 Pages, 2001/12
JAERI-Tech-2001-086.pdf:5.23MB
Project management data on dismantling the Japan Power Demonstration Reactor (JPDR) was calculated using the Code System for Planning and Management of Reactor Decommissioning (COSMARD), and then its validity was studied by comparing the calculation results with actual data. In addition, work breakdown structure models and database were modified to meet an evaluation with changing work difficulty of preparation and cleanup activities, and calculations were further conducted to analyze feasibility by changing various conditions on cutting and conditioning activities. As the results, COSMARD was verified to be useful by confirming calculation capability on reflection of actual work conditions and relatively good agreement between actual data and calculations. Moreover, it was cleared that main parameters such as work difficulty of preparation and cleanup activities and the cutting speed in demolition work could affect to manpower within 30% in each calculations.
Shiraishi, Kunio; Sukegawa, Takenori; Yanagihara, Satoshi
JAERI-Data/Code 2001-028, 86 Pages, 2001/11
JAERI-Data-Code-2001-028.pdf:6.31MB
The data on worker dose in dismantling of the Japan Power Demonstration Reactor (JPDR) was analyzed to characterize its features. It was appeared from the study that the collective dose to the workers was 306 man-mSv, in which maximum individual dose was 8.5 mSv, almost all doses were received in the activities for dismantling of reactor internals, the reactor pressure vessel and the biological shield, and that the worker dose distribution was similar to that in the maintenanee of the facilities which was characterized by the hybrid log normal distribution model. Farthermore, it was found that the dismantling activities were categorized into three groups depending on dose rates in workplaces, then contribution factors for radiation exposure in terms of dose rates in different groups were derived based on the analysis. The study would be useful for estimation of worker dose in future decommissioning of commercial nuclear power plants in Japan.
Yanagihara, Satoshi; Sukegawa, Takenori; Shiraishi, Kunio
Journal of Nuclear Science and Technology, 38(3), p.193 - 202, 2001/03
no abstracts in English
Hieu, N. M.*; Kumazawa, Shigeru
JAERI-Research 2000-065, 28 Pages, 2001/02
JAERI-Research-2000-065.pdf:1.63MB
no abstracts in English
Onodera, Junichi;
IAEA-CN-54/65P, 0, p.306 - 309, 1996/00
no abstracts in English
Matsui, Hiroshi; Ikezawa, Yoshio
Firumu Bajji Nyusu, 0(161), p.7 - 10, 1990/05
no abstracts in English
