著者
松村 宏 斎藤 究 石岡 純 上蓑 義朋
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会和文論文誌 (ISSN:13472879)
巻号頁・発行日
vol.10, no.3, pp.152-162, 2011 (Released:2011-07-29)
参考文献数
3
被引用文献数
13 or 0

In Fukushima and neighboring prefectures, the distributions of dose rate and γ-ray count rate of radionuclides from the Fukushima Daiichi Nuclear Power Station were measured on expressways on March 15, 16, 17, and April 8, 2011, using an NaI(Tl) detector and a LaBr3 detector. A radioactive plume that contained 133Xe, 132Te, 132I, 131I, 134Cs, and 136Cs was observed at Koriyama on the afternoon of March 15. The plume arrived in the Nakadori region of Fukushima prefecture, which is surrounded by two mountain ranges, and most of the radioactivity there was deposited by rainfall. Although the distributions of 132Te, 132I, 134Cs, 136Cs, and 137Cs were similar, the distribution of 131I was different from the others. The effective nuclides for the dose rate measurement were 132Te and 132I on March 15-17 and 134Cs and 137Cs on April 8. The initial distribution profile of the dose rate on March 15-17 was retained on April 8 because the deposited radioactive material was not moved from the initial location and there was no additional effective deposition of radioactivity.
著者
古野 朗子 茅野 政道 山澤 弘実
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会和文論文誌 (ISSN:13472879)
巻号頁・発行日
vol.5, no.3, pp.229-240, 2006-09-25 (Released:2010-01-21)
参考文献数
20
被引用文献数
7 or 0

This paper describes a method of estimating source term, i.e., location, period and amount of atmospheric release of radioactive material in real-time during nuclear emergency. This method consists of: (1) trial simulations of atmospheric dispersions on the possible combinations of these parameters and (2) statistical comparison of model predictions with offsite measurements of air concentrations of radionuclides and/or air dose rates from monitoring stations, to find a set of release condition providing model prediction that fits best to the measurement. A parallel execution method for efficiently processing many possible initial conditions is also developed. The performance of this method is favorably evaluated by a verification study using the dataset from European Tracer Experiment.
著者
坂本 文徳 大貫 敏彦 香西 直文 五十嵐 翔祐 山崎 信哉 吉田 善行 田中 俊一
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会和文論文誌 (ISSN:13472879)
巻号頁・発行日
pp.1111290030-1111290030, (Released:2011-11-30)
参考文献数
12
被引用文献数
4 or 0

The environmental behavior of radioactive Cs in the fallout from the accident of the Fukushima Daiichi Nuclear Power Plant has been studied by measuring its spatial distribution on/in trees, plants, and surface soil beneath the plants using autoradiography analysis. The results of autoradiography analysis showed that radioactive Cs was distributed on the branches and leaves of trees that were present during the accident and that only a small fraction of radioactive Cs was transported to new branches and leaves grown after the accident. Radioactive Cs was present on the grass and rice stubble on the soils, but not in the soils beneath the grass and rice stubble, indicating that the radioactive Cs was deposited on the grass and the rice plant. In addition, the ratio of the radioactive Cs that penetrated into the soil layer by weathering was very small two months after the accident. These results indicate that trees and other plants are the reservoir of the fallout Cs and function to retard the fallout Cs migration with rain water.

21 1 1 0 OA LOFT計画の成果

著者
日本原子力研究所LOCA研究委員会・LOFT専門部会
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会誌 (ISSN:00047120)
巻号頁・発行日
vol.26, no.5, pp.375-383, 1984-05-30 (Released:2009-04-21)
参考文献数
4
被引用文献数
1 or 0
著者
西原 健司 山岸 功 安田 健一郎 石森 健一郎 田中 究 久野 剛彦 稲田 聡 後藤 雄一
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会和文論文誌 (ISSN:13472879)
巻号頁・発行日
pp.1202060058-1202060058, (Released:2012-02-08)
参考文献数
15
被引用文献数
15 or 0

After the severe accident in the Fukushima-1 nuclear power plant, a large amount of contaminated stagnant water has been produced in turbine buildings and surrounding areas. This rapid communication reports the calculation of the radionuclide inventory in the core, the collection of the measured inventory in the stagnant water, and the estimation of the radionuclide release ratios from the core to the stagnant water. The present evaluation is based on data obtained before June 3, 2011. It was revealed that the release ratios of tritium, iodine and cesium were several tens of percent, while those of strontium and barium were smaller by one or two orders of magnitude. These release ratios of the Fukushima accident were equivalent to those of the TMI-2 accident.
著者
中村 隆夫 中田 節也 岩田 吉左 小野 勤 濵﨑 史生
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会和文論文誌 (ISSN:13472879)
巻号頁・発行日
vol.13, no.3, pp.75-86, 2014 (Released:2014-08-15)
参考文献数
11
被引用文献数
2 or 0

Japan is one of the countries with abundant active volcanoes and has a long history of developing countermeasures to mitigate volcanic disasters. In the field of nuclear energy, it is also necessary to assess safety against volcanic hazards, and in 2009, a voluntary guideline was published as JEAG 4625 in order to set up requirements of site assessments and basic designs of nuclear power plants (NPPs). This guideline has been revised to satisfy the requirements for examining the necessity of considering volcanic phenomena and concrete countermeasures in detailed designs of NPPs. This paper focuses on the background and technical basis of this voluntary guideline and shows the basic policy to ensure the safety of NPPs and the requirements to prevent nuclear hazards due to volcanic phenomena based on the Defense in Depth Concept.
著者
藤高 和信
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会誌 (ISSN:00047120)
巻号頁・発行日
vol.35, no.10, pp.880-884, 1993-10-30 (Released:2010-04-19)
参考文献数
10
被引用文献数
1 or 0
著者
西原 健司 山岸 功 安田 健一郎 石森 健一郎 田中 究 久野 剛彦 稲田 聡 後藤 雄一
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会和文論文誌 (ISSN:13472879)
巻号頁・発行日
vol.11, no.1, pp.13-19, 2012 (Released:2012-02-15)
参考文献数
15
被引用文献数
15 or 0

After the severe accident in the Fukushima-1 nuclear power plant, a large amount of contaminated stagnant water has been produced in turbine buildings and surrounding areas. This rapid communication reports the calculation of the radionuclide inventory in the core, the collection of the measured inventory in the stagnant water, and the estimation of the radionuclide release ratios from the core to the stagnant water. The present evaluation is based on data obtained before June 3, 2011. It was revealed that the release ratios of tritium, iodine and cesium were several tens of percent, while those of strontium and barium were smaller by one or two orders of magnitude. These release ratios of the Fukushima accident were equivalent to those of the TMI-2 accident.
著者
平山 英夫 松村 宏 波戸 芳仁 佐波 俊哉
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会和文論文誌 (ISSN:13472879)
巻号頁・発行日
vol.14, no.1, pp.1-11, 2015 (Released:2015-02-15)
参考文献数
13
被引用文献数
2 or 0

Time histories of the I-131 concentration in air at monitoring posts in Fukushima prefecture in March 2011 were estimated using the pulse height distribution of a NaI(Tl) detector, which was opened to the public. Several corrections to the pulse height distribution were necessary owing to high count rates. The contribution to the count rates from I-131 accumulated around the monitoring post was estimated on the basis of the time history of the peak count rate by the method proposed by the authors. The concentrations of I-131 in air were converted from the peak count rates using the calculated response of the NaI(Tl) detector with egs5 for a model of a plume containing I-131 uniformly. The obtained time histories of the I-131 concentration in air at a fixed point in March 2011 were the first ones for Fukushima prefecture. The results at 3 monitoring posts, Naraha Town Shoukan, Hirono Town Futatunuma and Fukushima City Momijiyama, which can be analyzed during almost all of March, show that a plume including I-131 arrived after March 15. The results at other monitoring posts near Fukushima Daiichi Nuclear Power Station are used to characterize plume diffusion at the early period of the accident before March 15. The I-131 time-integrated concentrations in air at several monitoring posts were compared with those given in UNSCEAR 2013 ANNEX A, which were obtained using estimated time-dependent rates of release to the atmosphere. The agreement between the two results varies depending on the places compared, owing to the large uncertainties in the estimated release rate used in UNSCEAR. The results obtained in this study can be used to increase the accuracy of the time-dependent release rate estimation.
著者
斯波 正誼 天野 文雄
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会誌 (ISSN:00047120)
巻号頁・発行日
vol.23, no.10, pp.736-745, 1981-10-30 (Released:2009-04-21)
参考文献数
21

The report presents the summary of Stockholm Conference held on October 20-24, 1980 sponsored by IAEA, where current nuclear power plant safety issues were discussed.Some technical topics are reviewed that include (1) examining nuclear safety, (2) siting policy, (3) designing for safety, (4) operational safety, (5) emergency planning, and (6) risk assessment, small leak loss of coolant accidents.
著者
北田 淳子
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会和文論文誌 (ISSN:13472879)
巻号頁・発行日
vol.12, no.3, pp.177-196, 2013 (Released:2013-08-15)
参考文献数
29
被引用文献数
3 or 0

In this study, the results of surveys conducted over the past 30 years were analyzed. The surveys include continuous opinion polls conducted by seven organizations, those conducted by eight news media one year after the Fukushima Daiichi accident, and those conducted by INSS fourteen times from 1993 to December 2011. The results were as follows: (1) Negative opinions toward nuclear power generation (NPG) suggesting “abolition or reduction”, which used to be 20-30% over the past 30 years, increased to 70% from four to six months after the accident, when there was also much news about renewable energy. (2) Even after the accident, 60% regarded NPG as “inevitable”, but many opposed future replacement or new construction of NPG facilities. (3) After the accident, recognition of the usefulness of NPG and concerns about electric power shortages in the near future remained unchanged, while anxiety and distrust toward NPG increased significantly. When considering power generation options, people now tend to focus on accident risks. (4) Nevertheless, people are neither aware of various possible problems caused by reducing NPG nor willing to accept a significant increase in electricity rate caused by the shift to renewable energy.
著者
長縄 弘親 熊沢 紀之 斉藤 浩 柳瀬 信之 三田村 久吉 永野 哲志 鹿嶋 薫 福田 達也 吉田 善行 田中 俊一
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会和文論文誌 (ISSN:13472879)
巻号頁・発行日
pp.1109220007-1109220007, (Released:2011-09-27)
参考文献数
7
被引用文献数
2 or 0

We tried the decontamination of surface soils for three types of agricultural land at Nagadoro district of Iitate-mura (village) in Fukushima Prefecture, which is highly contaminated by deposits of radionuclides from the plume released from the Fukushima Daiichi nuclear power plant. The decontamination method consisted of the peeling of surface soils solidified using a polyion complex, which was formed from a salt solution of polycations and polyanions. Two types of polyion complex solution were applied to an upland field in a plastic greenhouse, a pasture, and a paddy field. The decontamination efficiency of the surface soils reached 90%, and dust release was effectively suppressed during the removal of surface soils.
著者
小林 健介 堀井 英雄 石神 努 千葉 猛美
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会誌 (ISSN:00047120)
巻号頁・発行日
vol.27, no.1, pp.56-65, 1985-01-30 (Released:2009-04-21)
参考文献数
10
被引用文献数
1 or 0

A sensitivity analysis of thermal hydraulic response in containment during a 'station blackout' (the loss of all AC power) accident at Browns Ferry unit one plant was performed with the computer code MARCH 1.0. In the analysis, the plant station batteries were assumed to be available for 4h after the initiation of the accident. The thermal hydraulic response in the containment was calculated by varying several input data for MARCH 1.0 independently and the deviation among calculated results were investigated.The sensitivity analysis showed that (a) the containment would fail due to the overtemperature without any operator actions for plant recovery, which would be strongly dependent on the model of the debris-concrete interaction and the input parameters for specifying the containment failure modes in MARCH 1.0, (b) a core melting temperature and an amount of water left in a primary system at the end of the meltdown were identified as important parameters which influenced the time of the containment failure, and (c) experimental works regarding the parameters mentioned above could be recommended.
著者
水田 浩
出版者
一般社団法人 日本原子力学会
雑誌
日本原子力学会誌 (ISSN:00047120)
巻号頁・発行日
vol.16, no.5, pp.241-246, 1974-05-30 (Released:2009-04-21)

The most important safety problem concerning the LMFBR is related to core component damage caused by molten fuel coolant interaction. This problem has been reviewed under the items of out-of-pile test, in-pile test and analytical models. The elements of the physical geometry relevant to the out-of-pile test are shocktube, tank, jet injection, mixing and fuel pin. The major difficulty is to melt the large amount required of fuel (10kg). The in-pile test facilities operative today are TREAT, ETR, CABRI and HFR. Almost all the analytical models are based on the Cho-Wright model.