著者

近藤 健次郎 平山 英夫 平 雅文 松村 宏 岩瀬 広 佐々木 慎一

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.J14.034, (Released:2015-06-30)

参考文献数

16

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Strontium-90/Y-90 are major radionuclides observed in the water samples tested recently at the site of the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company. A simple method of evaluating Sr-90 concentration in these water samples by measuring β rays from Y-90 with a GM-detector setup was developed. By applying the precipitation method, Sr-90 and Y-90 were separated and quantitatively collected with a filter. β rays from Y-90 in the filter were measured two times at appropriate intervals by inserting a polyethylene plate of 2 mm thickness as a β-ray absorber. The contribution of γ rays from Cs-134 and Cs-137 to the Y-90 count rates was quantitatively evaluated using a 10-mm-thick acrylic resin plate. From the parent-daughter relationship between Sr-90 and Y-90, the Sr-90 concentration was evaluated using the conversion coefficient of Y-90 count rate (cps) to Sr-90 concentration (Bq/cm3). It was verified that Sr-90 concentration of below 0.01 Bq/cm3 in water samples can be correctly measured by this simple method.

著者

渡邉 憲夫 与能本 泰介 玉置 等史 中村 武彦 丸山 結

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.2, pp.113-127, 2013 (Released:2013-05-15)

参考文献数

19

被引用文献数

1 1

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On March 11, 2011, the Tohoku District-off the Pacific Ocean Earthquake and the subsequent tsunami resulted in the severe core damage at TEPCO's Fukushima Dai-ichi Nuclear Power Station Units 1-3, involving hydrogen explosions at Units 1, 3, and 4 and the large release of radioactive materials to the environment. Four independent committees were established by the Japanese government, the Diet of Japan, the Rebuild Japan Initiative Foundation, and TEPCO to investigate the accident and published their respective reports. Also, the Nuclear and Industrial Safety Agency carried out an analysis of accident causes to obtain the lessons learned from the accident and made its report public. This article reviews the reports and clarifies the differences in their positions, from the technological point of view, focusing on the accident progression and causes. Moreover, the undiscussed issues are identified to provide insights useful for the near-term regulatory activities including accident investigation by the Nuclear Regulation Authority.

著者

木村 謙仁

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.2, pp.138-148, 2013 (Released:2013-05-15)

参考文献数

72

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The French history of nuclear development clearly shows the inseparability of its civilian use from military use. In France, Commissariat à l'Énergie Atomique (CEA) and Électricité de France (EDF) have played an important role in research and development of nuclear technology since the postwar period. At first, the two organizations had kept great autonomy, but the government reinforced its control on them because France needed nuclear deterrence against the Soviet Union. France began using plutonium in 1952, and the Suez crisis in 1956 showed the need for nuclear force to ensure its independence. After this event, France managed the first nuclear test using plutonium in 1960. As for enriched uranium, they have long had great difficulty in securing it. The uranium enrichment technology became crucial also in civilian use in this period. EDF proposed the pressurized water reactor (PWR), which requires enriched uranium, as the future reactor type because of its economic advantage, but CEA wanted to continue developing the gas-cooled reactor (GCR) because of its independence in nuclear fuel supply. Finally, they chose PWR because a French enrichment facility was built in 1967. From such French history, we can say that the civilian and military use of nuclear technology are inseparable.

著者

桜井 淳

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.1, no.4, pp.462-468, 2002-12-25 (Released:2010-01-21)

参考文献数

31

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The technology of light water reactor will continue as a realistic energy technology for about half century at least from now on. The social agreement is necessary to continue nuclear power generation. Nuclear community must renew the conventional thought partially and have to approach the thought close to the value judgment in another social coordinate. "The Sociology of Science" on the atomic energy shall be such contents that be able to contribute to the unify or to attaches both coordinates as near as possible.

著者

町田 昌彦 岩田 亜矢子 山田 進 乙坂 重嘉 小林 卓也 船坂 英之 森田 貴己

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.J20.036, (Released:2022-01-26)

参考文献数

53

被引用文献数

4

---

We estimate the monthly discharge inventory of tritium from the port of Fukushima Daiichi Nuclear Power Plant (1F) from Jun. 2013 to Mar. 2020 using the Voronoi tessellation scheme, following the tritium monitoring inside the port that started in Jun. 2013. As for the missing period from the initial month, Apr. 2011 to May 2013, we calculate the tritium discharge by utilizing the ratio of tritium concentration to 137Cs concentration in stagnant contaminant water during the initial direct run-off period to Jun. 2011 and the discharge inventory correlation between tritium and 137Cs for the next-unknown continuous-discharge period up to May 2013. From all the estimated results over 9 years, we found that the monthly discharge inventory sharply dropped immediately after closing the seaside impermeable wall in Oct. 2015 and subsequently coincided well with the sum of those of drainage and subdrain etc. By comparing the estimated results with those in the normal operation period before the accident, we point out that the discharge inventory from the 1F port after the accident is not very large. Even the estimation for the year 2011 is found to be comparable to the maximum of operating pressurized water reactors releasing relatively large inventories in the number of digits. In the national level, the total domestic release inventory in Japan significantly decreased after the accident owing to the operational shutdown of most plants. Furthermore, 1F and even the total Japanese discharge inventory are found to be minor compared with those of nuclear reprocessing plants and heavy-water reactors on a worldwide level. From the above, we suggest that various scenarios can be openly discussed regarding the management of tritium stored inside 1F with the help of the present estimated data and its comparison with the past discharge inventory.

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

pp.J14.027, (Released:2015-01-28)

参考文献数

13

被引用文献数

9 9

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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

稲村 智昌 班目 春樹

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.8, no.4, pp.320-331, 2009 (Released:2012-02-22)

参考文献数

31

被引用文献数

1 1

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The confidentiality system concerning the physical protection of nuclear materials and nuclear facilities was enacted by revision of the Nuclear Reactor Regulation Law in 2005. We made a comparative analysis with the information security in governmental agencies or financial sectors, in order to consider the way the sensitive information management concerning the physical protection of nuclear materials and nuclear facilities should be. The considerations in this paper are as follows. (1) In order to secure a suitable level of security, close cooperation should be achieved among related governmental agencies. (2) A cycle that continuously evaluates whether suitable management is performed should be established. (3) Excessive secretiveness should be eliminated. (4) An information-sharing system among the related persons beyond the frame of governmental agencies and electricity companies should be established. (5) Improvement in the social acceptability of the sensitive information management is important. (6) Although it is important to perform evaluation by the consideration of suitable balance with information disclosure, it is also important that it is positively shown to society.

著者

篠田 佳彦 土田 昭司 木村 浩

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.13, no.3, pp.94-112, 2014 (Released:2014-08-15)

参考文献数

19

被引用文献数

1 2

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Fukushima Daiichi nuclear power plant accident (Fukushima accident) has brought about a great change in many people's perceptions about nuclear power plant safety. When discussing future energy options for Japan, it is important to have a full grasp of the attitude of a large number of people towards nuclear energy. The Atomic Energy Society of Japan has conducted annual questionnaire survey of 500 adults who live within 30 kilometers of Tokyo Station. The aim of this survey is to assess trends in public attitude towards nuclear energy. The authors that designed the questionnaire entries of this survey have been managing questionnaire data as members of the Data Management Working Group under the Social and Environmental Division of the Atomic Energy Society of Japan. We confirmed the change in public attitude towards nuclear energy through this periodical survey after the Fukushima accident. In particular, public concerns about the use of nuclear energy increased after the Fukushima accident, and many people have raised doubts over the use of nuclear energy in the future.

著者

武井 正信 小杉山 真一 毛利 智聡 片西 昌司 國富 一彦

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.2, pp.109-117, 2006-06-25 (Released:2010-01-21)

参考文献数

23

被引用文献数

8 12

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Japan Atomic Energy Research Institute (JAERI) has been developing a graphite moderate and helium cooled High Temperature Gas-cooled Reactor (HTGR) with gas turbine, the GTHTR300 based on experience gained in development and operations of the High Temperature Engineering Test Reactor (HTTR) in JAERI. The GTHTR300 is a simplified and economical power plant with a high level of safety characteristics and a high plant efficiency of approximately 46%. Cost evaluation for plant construction and power generation is studied in order to clarify the economical feasibility of the GTHTR300. The construction cost is estimated to be about 200 thousands Yen/kWe. The power generation cost is estimated to be about 3.8Yen/kWh by the conditions of 90% load factor and 3% discount rate. The economical feasibility of the GTHTR300 is certified. The present study is entrusted from Ministry of Education, Culture, Sports, Science and Technology of Japan.

著者

三枝 博光 舟木 泰智 操上 広志 坂本 義昭 時澤 孝之

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.1, pp.1-12, 2013 (Released:2013-02-15)

参考文献数

6

被引用文献数

1

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Since the Fukushima Daiichi nuclear power plant accident caused by the Tohoku Region Pacific Coast Earthquake on March 11, 2011, decontamination work has been conducted in the surrounding environment within the Fukushima prefecture. Removed contaminants including soil, grass and trees are to be stored safely at temporary storage facilities for up to three years, after which they will be transferred to a planned interim storage facility. The decontamination pilot project was carried out in both the restricted and planned evacuation areas in order to assess decontamination methods and demonstrate measures for radiation protection of workers. Fourteen temporary storage facilities of different technical specifications were designed and constructed under various topographic conditions and land use. In order to support the design, construction and monitoring of temporary storage facilities for removed contaminants during the full-scale decontamination within the prefecture of Fukushima, technical know-how obtained during the decontamination pilot project has been identified and summarized in this paper.

著者

町田 昌彦 岩田 亜矢子 山田 進 乙坂 重嘉 小林 卓也 船坂 英之 森田 貴己

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.22, no.1, pp.12-24, 2023 (Released:2023-01-18)

参考文献数

54

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We estimate the inventory of tritium in two sea areas corresponding to coastal and offshore ones around Fukushima Daiichi Nuclear Power Plant (1F) on the basis of the measured seawater tritium concentrations monitored constantly from 2013 to Jan. 2021 by using the Voronoi tessellation scheme. The obtained results show that the offshore area inventory and its temporal variation amount correspond to approximately 1/5 and 1/50 of that of the treated water accumulated inside 1F, respectively. These results suggest that the amount of tritium included in seawater as the background is non-negligible in evaluating the environmental impact of releasing the accumulated treated water into the sea area. We also estimate the offshore area inventory before the 1F accident and find that it had exceeded the 1F stored inventory over 30 years from 1960s to 1980s, being approximately 4 times larger in the peak decade 1960s. This finding means that we had already experienced more contaminated situations over 30 years in the past compared with the conservative case emerged by just releasing whole the present 1F inventory. Here, it should also be emphasized that the past contamination situation was shared by the entire world. We further extend the estimation area to include the offshore area from Miyagi to Chiba Prefectures and find that the average area inventory is now comparable to half the present 1F inventory. Finally, we estimate the internal dose per year by ingesting fishes caught inside the area when the 1F inventory is added only inside the area and kept there for one year. The result indicates that it approximately corresponds to 1.0 × 10−6 of the dose from natural radiation sources. From these estimation results, we find that all the tritium inventories stored inside 1F never contribute to significant dose increment even when it is instantly released into the area.

著者

町田 昌彦 山田 進 岩田 亜矢子 乙坂 重嘉 小林 卓也 渡辺 将久 船坂 英之 森田 貴己

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.18, no.4, pp.226-236, 2019 (Released:2019-11-20)

参考文献数

34

被引用文献数

9

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After direct discharges of highly contaminated water from Units 2 and 3 of the Fukushima Daiichi Nuclear Power Plant (1F) from April to May 2011, Kanda suggested that relatively small amounts of run-off of radionuclides from the 1F port into the Fukushima coastal region subsequently continued, on the basis of his estimation method. However, the estimation period was limited to up to September 2012, and there has been no report on the issue since that work. Therefore, this paper focuses on the discharge inventory from the 1F port up to June 2018. In the missing period, the Japanese government and Tokyo Electric Power Company Holdings have continued efforts to stop the discharge, and consequently, the radionuclide concentration in seawater inside the 1F port has gradually diminished. We show the monthly discharge inventory of 137Cs up to June 2018 by two methods, i.e., Kanda’s method partially improved by the authors and a more sophisticated method using Voronoi tessellation reflecting the increase in the number of monitoring points inside the 1F port. The results show that the former always yields overestimated results compared with the latter, but the ratio of the former to the latter is less than one order of magnitnde. Using these results, we evaluate the impact of the discharge inventory from the 1F port into the coastal area and the radiation dose upon fish digestion.

著者

山田 祥徳 酒井 幹夫 水谷 慎 越塚 誠一 大地 雅俊 室園 浩司

出版者

Atomic Energy Society of Japan

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.185-193, 2011 (Released:2011-08-24)

参考文献数

21

被引用文献数

27 26

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In nuclear engineering, fluid flows involving free surface were well studied, e.g., pipe thinning produced by liquid droplet impingement, and steam explosion triggered by molten metal immersed in water. The moving particle simulation (MPS) method was often used in past studies. In this method, the Poisson equation was solved to obtain the pressure field. Solving the Poisson equation becomes a dominant process. Reducing the time of calculation of the Poisson equation is important for using the CFD in the engineering fields. Thereat, we propose a new MPS method by which the pressure field is calculated explicitly. We call it the explicit (E-)MPS method. The E-MPS method was applied to a static water and dam break problem to show its adequacy. Besides, we compare the calculation time between the E-MPS method and traditional one.

著者

飯島 亨 安部 浩 鈴木 謙一

出版者

Atomic Energy Society of Japan

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.7, no.2, pp.99-111, 2008 (Released:2012-03-02)

参考文献数

9

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The seismic probabilistic safety assessment (PSA) is an available method for evaluating the residual risk of nuclear plants, which are designed under definitive seismic design conditions. Our preliminary seismic PSA analysis has indicated that the malfunction of electric panels would have a significant influence on the core damage frequency (CDF). In recent years, there has been a growing desire to raise the reliability of the seismic PSA; thus, a higher seismic capacity of the electric panels is necessary. The Japan Nuclear Energy Safety Organization (JNES) tested eight kinds of main electric panels and thirty kinds of main electric parts at high acceleration, which considerably exceeds the design level. From the test results, JNES obtained precise seismic capacity data of the electric panels that have a significant effect on CDF. JNES also proposed a method of evaluating seismic capacity. The method can use the seismic capacity data of electric parts and the acceleration amplification ratios calculated from the FEM analysis. JNES expects that the seismic capacity data obtained from this study will increase the reliability of the seismic PSA.

著者

辰巳 智行 中澤 高師

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.J20.006, (Released:2021-05-12)

参考文献数

36

被引用文献数

1

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Not just whether nuclear power stations should be restarted, but how local agreement over the restart should be achieved has been controversial issues in Japan since the Fukushima Nuclear Disaster. In this paper, public attitudes towards local agreement in the case of Hamaoka Nuclear Power Plants are explored with a postal questionnaire survey in Shizuoka prefecture. Through descriptive statistics and factor analysis, the study shows that extending the “local” scale and judgement by ordinary citizens is given more support than the conventional local agreement process. Factor analysis reveals three factors behind respondents’ attitudes towards local agreement: “conventional decision-makers”, “narrow localism” and “national interests”. The analysis of the factor scores reveals that attitudes towards local agreement differ depending on attitudes towards the restart of the plant and the prefectural referendum, as well as generation, while no significant difference is found among genders and residential areas excluding the second factor. By clarifying the public attitudes towards how local agreement should be made, this study makes a significant step toward the design of a socially more agreeable local agreement.

著者

山本 晃弘 関村 直人

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.J16.002, (Released:2017-06-27)

参考文献数

59

被引用文献数

1

---

The enhancement of safety culture is an issue for both plant operators and regulators working in fields related to the safety management of nuclear power plants. Plant operators have been collecting safety culture data through a broad range of tools and methods such as observations, interviews and other surveys. However, many issues remain regarding the effectiveness of safety culture activity. A new regulatory authority was established in 2012 after the Fukushima Dai-ichi accident to enforce nuclear safety regulations but its activity is still weak in terms of monitoring the performance of plant operators’ safety culture. In order to promote and strengthen safety culture, plant operators need to collect detailed event information, even when events do not directly affect plant safety, and accumulate information related to human, organizational and technical factors through dialogue among the parties responsible for coping with events. Both operators and regulators should all be working in the same direction to assess information that will help their periodic reviews, and the involvement of local government is a key to enhancing their safety culture.

著者

松井 亮太

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.19, no.3, pp.136-146, 2020 (Released:2020-08-20)

参考文献数

30

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A deliberative poll (DP) is a new type of democratic process in which citizens selected at random from the voters are educated on and discuss given political issues, and then the results are reflected in policy. An example of this occured in 2012 when the Japanese government conducted a DP on nuclear power generation goals for 2030. As a result, support for abolishing nuclear power increased significantly. On the other hand, in 2017, the Korean government conducted a DP on the construction of the Shin-Gori nuclear reactors and on future nuclear policy. As a result, support for the continued construction of the reactors and phase out of nuclear power was strengthened. In Japan’s DP compared with that of Korea’s, Japan’s selected citizens were far less representative of the population, stakeholder’s involvement was nonexistent, and the government was much less committed.

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.2, pp.175-175, 2013 (Released:2013-05-15)

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撤回:Zr-Ni 合金粒子充填塔による不活性ガス中の水素同位体の吸収破過および脱離特性三石信雄1),深田 智1),谷村徳孝1),野崎貴之1)九州大学工学部応用原子核工学教室1)三石信雄らにより著作された論文「Zr-Ni 合金粒子充填塔による不活性ガス中の水素同位体の吸収破過および脱離特性」日本原子力学会誌 Vol. 29 No. 2 (1987) p. 151-157 は,ほとんど同内容の論文が他誌に先に掲載されており,二重投稿であることが判明したので,本誌より削除した。 一般社団法人 日本原子力学会編集委員会 論文誌編集長 矢野豊彦

著者

波戸 真治 木名瀬 栄

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.15, no.3, pp.146-150, 2016 (Released:2016-08-15)

参考文献数

5

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It is important to accurately estimate the intake quantity for reliable internal exposure assessments. The intake quantity has been estimated by using the least-squares method. However, to use the least-squares method, the number of radioactivity measurements must be more than the number of intakes. To remedy this restriction, this study suggests an estimation method using singular value decomposition that is available regardless of the relation between the numbers of measurements and intakes. Moreover, this study introduces a procedure to calculate the intake quantity from the measurements with uncertainty.

著者

佐波 俊哉 佐々木 慎一 飯島 和彦 岸本 祐二 齋藤 究

出版者

Atomic Energy Society of Japan

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.163-169, 2011 (Released:2011-07-29)

参考文献数

6

被引用文献数

11 11

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The time variations in the dose rate and γ spectrum of radio nuclides originating from the accident of Fukushima Daiichi Nuclear Power Station were measured at Tsukuba City, Ibaraki, during the period from 15th March to 9th April 2011. The radiation dose peaked three times during the period from 15th to 16th March (1.27 μSv/h at maximum). The contribution of Xe-133 to the dose rate was observed from the γ spectrum obtained from the 5 h measurement during the peaks on 15th and 16th March, indicating that radioactive plume passed through Tsukuba City at that time. After the peaks, a dose rate increase with rainfall was observed on 21th March, dominating the integral dose rate measured at Tsukuba City. The dose after the rainfall comes from I-131, Cs-134, and Cs-137 that can be observed as peaks in the spectra.