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Takahara, Shogo; Iijima, Masashi*; Yoneda, Minoru*; Shimada, Yoko*
Risk Analysis, 39(1), p.212 - 224, 2019/01
Times Cited Count：5 Percentile：48.71(Public, Environmental & Occupational Health)A dose assessment model was developed based on measurements and surveys of individual doses and relevant contributors in Fukushima City for four population groups: Fukushima City Office staff, Senior Citizens' Club, Contractors' Association, and AgriculturalCooperative. In addition, probabilistic assessments were performed for these population groups by considering the spatial variability of contamination and interpopulation differencesresulting from behavior patterns. As a result of comparison with the actual measurements, the assessment results for participants from the Fukushima City Office, Senior Citizens' Club and the Agricultural Cooperative agreed with the measured values. By contrast, the measurements obtained for the participants from the Contractors' Association were not reproduced well in the present study. To assess the doses to this group, further investigations of association members' work activities and the related dose reduction effects are needed.
Takahara, Shogo; Ikegami, Maiko*; Yoneda, Minoru*; Kondo, Hitoshi*; Ishizaki, Azusa; Iijima, Masashi; Shimada, Yoko*; Matsui, Yasuto*
Risk Analysis, 37(7), p.1256 - 1267, 2017/07
Times Cited Count：6 Percentile：52.04(Public, Environmental & Occupational Health)Kurikami, Hiroshi; Malins, A.; Takeishi, Minoru; Saito, Kimiaki; Iijima, Kazuki
Journal of Environmental Radioactivity, 171, p.99 - 109, 2017/05
Times Cited Count：15 Percentile：43.57(Environmental Sciences)A modified diffusion-sorption-fixation model (mDSF) is proposed to describe the vertical migration of radiocesium in soils following fallout. The model introduces kinetics for reversible sites, meaning that the exponential-shape radiocesium distribution can be reproduced immediately following fallout. The initial relaxation mass depth of the distribution is determined by the diffusion length, which depends on the distribution coefficient, sorption rate and dispersion coefficient. The model captures the long tails of the radiocesium distribution at large depths. These tails are caused by different rates for kinetic sorption and desorption.
Furukawa, Tomohiro; Hirakawa, Yasushi; Kato, Shoichi; Iijima, Minoru; Otaka, Masahiko; Kondo, Hiroo; Kanemura, Takuji; Wakai, Eiichi
Fusion Engineering and Design, 89(12), p.2902 - 2909, 2014/12
Times Cited Count：9 Percentile：57.19(Nuclear Science & Technology)For the irradiation test of the candidate materials for the fusion DEMO reactor, Engineering Validation and Engineering Design Activities (EVEDA) of the International Fusion Materials Irradiation Facility (IFMIF) are performed under the Broader Approach Activities. As a major Japanese activity on the target facility of the IFMIF, the engineering validation using the EVEDA Lithium Test Loop which is the largest scale liquid lithium test loop has been started in 2012. In parallel with the design and fabrication, the research on the technology establishment for the lithium safety handling was started in 2008, as one of the related technologies under the IFMIF-EVEDA. In the research, experiments of lithium chemical reaction, experiments on lithium fire, establishment of chemical analysis of impurities in lithium and experiments on advanced lithium leak detection system were carried out. This paper describes the results of these experiments.
Nakai, Satoru; Aoyama, Takafumi; Ito, Chikara; Yamamoto, Masaya; Iijima, Minoru; Nagaoki, Yoshihiro; Kobayashi, Atsuko; Onoda, Yuichi; Ohgama, Kazuya; Uwaba, Tomoyuki; et al.
Kosoku Jikkenro "Joyo" Rinkai 30-Shunen Kinen Hokokukai Oyobi Gijutsu Koenkai, 154 Pages, 2008/06
no abstracts in English
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PNC TN9410 89-138, 50 Pages, 1989/08
Cover gas monitorring system was installed for obtaining the information of impurities concentration in the primary and secondary cover gas on JOYO, and it has been operated to these days. The experience results are as follows; (1)Increasing of impurities concentration in the cover gas were detected quickly by this system. (2)This system was able to detected the impurities concentration continuously, so it is very useful for investigation the cause of abnormal condition and observation the effect of cover gas purge. (3)This system was modified some points, consequently the measurement performance and reliability of data were advanced more than old one.
1987)*; *; ; *; *; *; *
PNC TN9450 88-005, 136 Pages, 1988/05
This paper is the impurities eontrol experience data collections in primary and secondary sodium and argon gas for the purpose of build up data base, from the initial sodium fill of the system in 1975 to the 100 MW cycle operation in 1987 in JOYO. Main results of the impurities monitoring in this period were as follows. (1)Impurities concentrations in primary and secondary sodium were generally within the control level of JOYO. (2)Although hydrogen and methane concentrations in primary argon gas exceeded the control level during maintenance of primary system main circulating pump and fuel handling works, other items were well controlled within the level. (3)Impurities concentrations in secondary argon gas were generally within the control level, except hydrogen concentration at the 6th periodical inspection and maintenance in 1987.
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PNC TN941 82-92, 42 Pages, 1982/04
Based on the results of basic function tests with an experimental on-line gas chromatograph, the improved on-line cover gas monitor was fabricated, and examinations were conducted to confirm actuation, performance and durability of this monitor. The results are summarised as followed; (1)It was confirmed that each functions of data typewriter, X-Y plotter and monitor panel, contained data display and alarm sending, etc., satisfied its specifications. (2)It was confirmed that the program of this monitor was correctly actuated during 2 times of continuous monitoring for 45 days period. (3)It was found that the slope factors of calibration curves obtained by the relative sensitivity method and the former absolute sensitivity method almost agreed. Using the relative sensitivity method, the required time to calibrate and to make the standard gas samples could be shorten to 1/4 and 1/6, respectively. (4)Three troubles occured during this test. However, these troubles will be able to avoid by regular inspection because these are essencially simple accidents.
