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Takahara, Shogo; Iijima, Masashi; Shimada, Kazumasa; Kushida, Teruo; Shiratori, Yoshitake
JAEA-Research 2014-024, 57 Pages, 2015/01
JAEA-Research-2014-024.pdf:5.49MB
In order to assess the doses to representative person using deterministic approach, we measured radiation dose rates and surveyed on behavioral patterns in the areas contaminated by the Fukushima Daiichi Nuclear Power Station Accident. Statistical analyzes were also performed to identify the characteristics of individual doses from external exposures, as well as radiation dose rates and behavioral patterns. Radiation dose rates measured in living areas distribute with lognormal form. Behavioral patterns of the populations were different corresponding to their occupation. Time spent outdoors of indoor workers were distributed in lognormal form and those of outdoor workers had the normal distribution. Multi-regression analyses were made to explore a significant relationship between individual doses and relevant contributors. These results indicated that the significant differences were given in individual doses due to the spatial differences of radiation dose rates as well as the interindividual differences of behavioral patterns. Based on the results of analyses of relevant contributors to the external exposures, deterministic dose assessment model was developed. The validity of this model was confirmed because the assessed values were higher than those measured.
Takahara, Shogo; Iijima, Masashi; Kushida, Teruo; Shiratori, Yoshitake
JAEA-Research 2013-029, 36 Pages, 2013/12
JAEA-Research-2013-029.pdf:2.7MB
In the areas contaminated by the Fukushima Daiichi Nuclear Power Plant accident, to clarify the influences of the lifestyle habits to radiation exposures for inhabitants, we performed surveys on their behavioral patterns and measurements of their individual doses due to external exposures. In addition, an assessment model was developed and the assessments of the doses were performed based on the results of the surveys and the measurements of ambient dose equivalent rates. The assessed individual doses were compared with those measured in order to confirm the validity of the model. Clear differences were found in time spent outdoors of the inhabitants of various occupations. Significant differences in individual doses were also observed between those of indoor workers and outdoor workers. In order to assess more precisely the doses of inhabitants who continue to live in the affected areas, assessments should be performed taking into account the population-specific behavioral patterns.
Yasuda, Ryo; Mita, Naoaki; Nishino, Yasuharu; Nakata, Masahito; Nozawa, Yukio; Harada, Katsuya; Kushida, Teruo; Amano, Hidetoshi
Nuclear Technology, 151(3), p.341 - 345, 2005/09
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)The Field Emission type Scanning Electron Microscope (FE-SEM), which is one of effective tools for observation of micr-structures, was installed at the Reactor Fuel Examination Facility (RFEF) in JAERI. The FE-SEM is equipped in a large shield vessel with remote handling systems to keep safety of operators and is modified to enable to manipulate high radioactive materials. The Energy Dispersive Spectrometer (EDS) with radiation-shielded collimators has been also equipped on the FE-SEM to determine element compositions of the observed material samples. Characterization tests were carried out using deposited gold film and Zircaloy cladding tubes with hydrides to confirm the machine performance after the modifications. In the results of the tests, high-resolution images without some noises and fogs were obtained with high magnification above 10,000. Those results show that the FE-SEM keeps the high performance after some improvements and modifications for shielding 
-rays and handling radioactive samples.
Onozawa, Atsushi; Kushida, Teruo; Kanazawa, Hiroyuki
JAERI-Tech 2004-061, 39 Pages, 2004/11
JAERI-Tech-2004-061.pdf:8.64MB
The swelling observed on irradiated fuels is caused by the accumulation of fission products and irradiation defects. The swelling ratio is changed along with radius region in the pellet due to burn up difference caused by that of neutron flux. To investigate the swelling behavior at the small area of the pellet, it is needed to measure the density of fuel fragments picked from an irradiated pellet. In this circumstance, once-through type densitometer was developed to measure the density of the small irradiated specimen precisely and to handle the samples easily with remote control systems. Several kinds of metallic and ceramic standard specimens are prepared to investigate the dependence of the sample weight, density and porosity on the accuracy. The results of characteristic examination using these specimens indicate that this densitometer has enough accuracy. In addition, some parts of this apparatus are controlled by motor drive units, which made it possible to measure the density full-automatically.
; Nishino, Yasuharu; ; Nakamura, Jinichi; *
JAERI-Tech 94-028, 147 Pages, 1994/11
no abstracts in English
; Nishino, Yasuharu;
JAERI-M 93-244, 93 Pages, 1994/01
no abstracts in English
; Nishino, Yasuharu; Yamahara, Takeshi;
Proc. of 42nd Conf. on Robotics and Remote Systems, 2, p.52 - 57, 1994/00
no abstracts in English
; Nishino, Yasuharu; Yamahara, Takeshi;
Transactions of the American Nuclear Society, 71, 522 Pages, 1994/00
no abstracts in English
