Study on disaster waste around Fukushima Daiichi NPS

International Nuclear Information System (INIS)

2012-01-01

Extreme difficulties exists in Fukushima Prefecture in disposing of waste generated from the tsunami disaster (hereinafter referred to as disaster waste) and contaminated with radioactive material released from the crippled Fukushima Daiichi Nuclear Power Station. Although the waste should be treated according to the level of radioactivity, there were only air dose rates and radionuclide analyses of soil due to monitoring around the Fukushima Daiichi Nuclear Power Station and there had been no information on the radioactivity concentration of the disaster waste. The radioactivity concentration of the disaster waste was investigated by sampling measurement and in-situ Ge measurement at 20 temporary disaster waste storages in Fukushima Prefecture excluding the evacuation zone and 'deliberate evacuation zone.' JNES carried out tins investigation upon a request from die Nuclear and Industrial Safety Agency. The investigation revealed that the measured radioactivity concentrations of the disaster waste lumps were enveloped within the soil monitoring readings in Fukushima Prefecture and also within a correlated curve between the air dose rates obtained from air dose rate readings around the disaster waste and the radioactivity concentrations of it. Based on the results of this study, JNES compiled a manual on measurement technique for contaminated disaster waste. (author)

Radioactive pollution from Fukushima Daiichi nuclear power plant in the terrestrial environment.

Science.gov (United States)

Tazoe, H; Hosoda, M; Sorimachi, A; Nakata, A; Yoshida, M A; Tokonami, S; Yamada, M

2012-11-01

Major contaminants from venting and hydrogen explosions at the Fukushima Daiichi nuclear reactors between 12 and 15 March 2011 were transported northwestward and deposited on soil and plants via precipitation. Surface soils and plant leaves were sampled at 64 sites in the Fukushima Prefecture. The highest concentrations of (134)Cs (84.4 kBq kg(-1)) and (137)Cs (82.0 kBq kg(-1)) in surface soils were observed at Nagadoro in Iidate village located 32 km northwest from the Fukushima Daiichi nuclear power plant. Furthermore, (131)I, (129)Te, (129 m)Te, (110 m)Ag and (140)La were detected in the same samples. Outer surface of plant leaves, such as bamboo, cabbage and grasses were highly contaminated at the high-dose rate areas of Tsushima and Minami-Tsushima in Namie town. Mugwort leaves that grew after the pollution event had extremely low concentration of radionuclides; however, the plant/soil radiocaesium ratio was 0.023 ± 0.006. It is anticipated that decomposition of fallen leaves will promote recycling of radionuclides in the environment.

Fukushima Daiichi nuclear acccident. Damaged facilities of the site - Situation as on March 2018

International Nuclear Information System (INIS)

2018-03-01

After a recall of the events that led to the Fukushima Daiichi accident, this note presents the situation in March 2018 of the actions of control of the damaged facilities and of their effluents. The last part presents the three steps of the facility control recovery plan retained by TEPCO

Report on Fukushima Daiichi NPP precursor events

International Nuclear Information System (INIS)

2014-01-01

The main questions to be answered by this report were: The Fukushima Daiichi NPP accident, could it have been prevented? If there is a next severe accident, may it be prevented? To answer the first question, the report addressed several aspects. First, the report investigated whether precursors to the Fukushima Daiichi NPP accident existed in the operating experience; second, the reasons why these precursors did not evolve into a severe accident. Third, whether lessons learned from these precursor events were adequately considered by member countries; and finally, if the operating experience feedback system needs to be improved, based on the previous analysis. To address the second question which is much more challenging, the report considered precursor events identified through a search and analysis of the IRS database and also precursors events based on risk significance. Both methods can point out areas where further work may be needed, even if it depends heavily on design and site-specific factors. From the operating experience side, more efforts are needed to ensure timely and full implementation of lessons learnt from precursor events. Concerning risk considerations, a combined use of risk precursors and operating experience may drive to effective changes to plants to reduce risk. The report also contains a short description and evaluation of selected precursors that are related to the course of the Fukushima Daiichi NPP accident. The report addresses the question whether operating experience feedback can be effectively used to identify plant vulnerabilities and minimize potential for severe core damage accidents. Based on several of the precursor events national or international in-depth evaluations were started. The vulnerability of NPPs due to external and internal flooding has clearly been addressed. In addition to the IRS based investigation, the WGRISK was asked to identify important precursor events based on risk significance. These precursors have

The Follow-up IAEA International Mission on Remediation of Large Contaminated Areas Off-Site the Fukushima Daiichi Nuclear Power Plant, Tokyo and Fukushima Prefecture, Japan, 14-21 October 2013. Final Report

International Nuclear Information System (INIS)

2014-01-01

In October 2011, the IAEA conducted an International Mission to Japan to support the remediation of large contaminated areas off-site TEPCO's Fukushima Daiichi Nuclear Power Plant (NPP). In response to the request made by the Government of Japan, in October 2013, the IAEA organized a follow-up International Mission on remediation of large contaminated areas off-site TEPCO's Fukushima Daiichi NPP (hereinafter referred to as the 'Follow-up Mission' or the 'Mission') with the main purpose of evaluating the progress of the on-going remediation works achieved since the previous mission in October 2011. The Follow-up Mission Team involved 13 international experts. Additionally, 3 experts of the Working Group 5 (Subgroup 5.2, Remediation) in charge of preparing the IAEA Report on TEPCO Fukushima Daiichi Accident accompanied the Mission as observers to obtain first-hand information for the report. The Follow-up Mission had the following three objectives: 1. To provide assistance to Japan in assessing the progress made with the remediation of the Special Decontamination Area (not included in the previous mission of 2011) and the Intensive Contamination Survey Areas; 2. To review remediation strategies, plans and works, in view of the advice provided by the previous mission on remediation of large contaminated off-site areas; and 3. To share its findings with the international community as lessons learned. The Mission was conducted through the assessment of information provided to the Team and by means of professional and open discussions with the relevant institutions in Japan, including national, prefectural and local institutions. The Japanese authorities provided comprehensive information on their remediation programme. The Mission Team visited the affected areas, including several sites where activities on remediation were conducted. The Team also visited some temporary storage sites for radioactive waste and soil generated in the remediation activities, as well as a

The Fukushima Daiichi nuclear accident final report of the AESJ investigation committee

CERN Document Server

Atomic Energy Society of Japan

2015-01-01

The Magnitude 9 Great East Japan Earthquake on March 11, 2011, followed by a massive tsunami struck  TEPCO’s Fukushima Daiichi Nuclear Power Station and triggered an unprecedented core melt/severe accident in Units 1 – 3. The radioactivity release led to the evacuation of local residents, many of whom still have not been able to return to their homes. As a group of nuclear experts, the Atomic Energy Society of Japan established the Investigation Committee on the Nuclear Accident at the Fukushima Daiichi Nuclear Power Station, to investigate and analyze the accident from scientific and technical perspectives for clarifying the underlying and fundamental causes, and to make recommendations. The results of the investigation by the AESJ Investigation Committee has been compiled herewith as the Final Report. Direct contributing factors of the catastrophic nuclear incident at Fukushima Daiichi NPP initiated by an unprecedented massive earthquake/ tsunami – inadequacies in tsunami measures, severe accident ma...

Assistance to the Fukushima Daiichi NPP accident

International Nuclear Information System (INIS)

Sakuma, Minoru

2012-01-01

Immediately after the reactor accident of Fukushima Daiichi Nuclear Power Plant occurring on March 11, 2011, JAEA started and continues to work with its every possible effort for remediation and has established the head quarter for countermeasure in Fukushima prefecture. The present paper includes main activities of assisting Fukushima area such as environmental monitoring and decontamination, technical advises to Japanese and local government, and others. Some are in cooperation with universities and others with Tokyo Electric Power Company. Towards closing the reactor accident, JAEA is joining the integrated activities for cooling the damaged reactor core and management of storing and disposal of radioactive wastes produced and large amount of remaining contaminated water to find out an adequate method for decontamination and preparing the manual for it. (S. Ohno)

Decommissioning and environmental remediation scenario development for Fukushima Daiichi

Energy Technology Data Exchange (ETDEWEB)

Kawamura, Hideki [mcm japan, Tokyo (Japan); Yashio, Shoko [Obayashi Corporation, Tokyo (Japan); McKinley, Ian G. [McKinley Consulting, Frick (Switzerland)

2017-07-15

Although the general approach to reactor decommissioning is well established, there is no direct precedent for managing the 6 units of the Fukushima Daiichi nuclear power plant. Apart from damaged reactors, challenges include extensive contamination of the entire reactor site and a huge tank farm currently storing contaminated cooling water. In order to move forward with planning decommissioning, it is important to decide on the desired end state of the site and understand the impact on such a decision on the costs, hazards and environmental impact of the project. A decommissioning roadmap and reference dismantling concept provide a basis for short-term planning, but the potential for technological optimisation should be carefully considered.

Questions concerning safety and risk after the nuclear accidents in Japan. Deepened accident analysis for the Fukushima Daiichi power plant; Sicherheits- und Risikofragen im Nachgang zu den nuklearen Stoer- und Unfaellen in Japan. Vertiefte Ereignisanalyse zur Anlage Fukushima-Daini

Energy Technology Data Exchange (ETDEWEB)

Pistner, Christoph; Englert, Matthias [Oeko-Institut e.V. - Institut fuer Angewandte Oekologie, Darmstadt (Germany)

2015-02-25

The study questions concerning safety and risk in Japanese power plants following the disastrous nuclear accident covers the following issues: the nuclear facility Fukushima Daiichi, site characterization, important technical equipment, important electro-technical equipment, personal; description of the accident progression in the Fukushima nuclear power plant: impact of the earthquake, impact of the tsunami, short-term measures of the operating personnel, pressure and temperature situation in the containments, restoration of the after-heat cooling system in the units 1/2 and 4, fuel element storage pool, summarized parameters during the accident progress; comparative analysis of the accident progression at the Fukushima Daiichi site.

Outline of the Fukushima Daiichi Accident. Lessons Learned and Safety Enhancements

Directory of Open Access Journals (Sweden)

Hirano Masashi

2017-01-01

This paper briefly presents the outline of the Fukushima Daiichi accident and summarizes the major lessons learned having been drawn and safety enhancements having been done in Japan for the purpose of giving inputs to the discussions to be taken place in the Special Invited Session “Fukushima, 5 years after”.

Emergency operating procedures improvement based on the lesson learned from the Fukushima Daiichi accident

Energy Technology Data Exchange (ETDEWEB)

Wu, Wen-Hsiung, E-mail: whwu1127@aec.gov.tw [Atomic Energy Council, 2F., No. 80, Sec.1, Chenggong Rd., Yonghe Dist., New Taipei City 234, Taiwan (China); Institute of Nuclear Engineering and Science, National Tsing Hua University, No. 101, Sec. 2, Guangfu Rd., Hsinchu City 300, Taiwan (China); Liao, Lih-Yih, E-mail: lyliao@iner.gov.tw [Institute of Nuclear Energy Research, Atomic Energy Council, No. 1000, Wenhua Rd., Jiaan Village, Longtan Township, Taoyuan County 325, Taiwan (China)

2016-12-01

Highlights: • Discuss the problem of EOPs at the time of Fukushima accident to deal with the prolonged SBO. • Elaborate the potential risk accompanied with the emergency depressurization in the SBO. • Describe a special guideline to cope with Fukushima-like accidents and provide its technical basis. • Point out that Fukushima accident might have been prevented if improved EOPs had been used. • Propose key points and suggestions for improving the EOPs. - Abstract: One of the lessons learned from the Fukushima Daiichi accident is the emergency operating procedures (EOPs) have to be improved. The BWR Owners’ Group revised the emergency procedure guidelines and addressed the lesson learned from the Fukushima Daiichi accident in revision 3 in order to avoid loss of turbine-driven makeup water systems during reactor depressurization. However, the improvement deserves much more attention. The existing EOPs at the time of the accident may not be adequate enough for the prolonged station blackout condition, because resources required for performing the EOPs are vastly unavailable or gradually exhausted. The improved EOPs must not only permit early reactor pressure vessel depressurization, but also address the risk accompanied with the emergency depressurization. For this reason, Taiwan Power Company proposed the Ultimate Response Guideline (URG) to cope with Fukushima-like accidents. The main content of the URG is a two-stage depressurization strategy, namely the controlled depressurization and the emergency depressurization. The technical basis of the two-stage depressurization strategy was discussed in this paper. The effectiveness of the URG was verified by using TRAC/RELAP Advanced Computational Engine (TRACE). Besides, the emergency responses performed by Fukushima Daini nuclear power plant (Fukushima Daini NPP) were found to be very similar to the URG. The consequences of Fukushima Daini NPP somehow demonstrate that the URG is effective for Fukushima

Emergency operating procedures improvement based on the lesson learned from the Fukushima Daiichi accident

International Nuclear Information System (INIS)

Wu, Wen-Hsiung; Liao, Lih-Yih

2016-01-01

Highlights: • Discuss the problem of EOPs at the time of Fukushima accident to deal with the prolonged SBO. • Elaborate the potential risk accompanied with the emergency depressurization in the SBO. • Describe a special guideline to cope with Fukushima-like accidents and provide its technical basis. • Point out that Fukushima accident might have been prevented if improved EOPs had been used. • Propose key points and suggestions for improving the EOPs. - Abstract: One of the lessons learned from the Fukushima Daiichi accident is the emergency operating procedures (EOPs) have to be improved. The BWR Owners’ Group revised the emergency procedure guidelines and addressed the lesson learned from the Fukushima Daiichi accident in revision 3 in order to avoid loss of turbine-driven makeup water systems during reactor depressurization. However, the improvement deserves much more attention. The existing EOPs at the time of the accident may not be adequate enough for the prolonged station blackout condition, because resources required for performing the EOPs are vastly unavailable or gradually exhausted. The improved EOPs must not only permit early reactor pressure vessel depressurization, but also address the risk accompanied with the emergency depressurization. For this reason, Taiwan Power Company proposed the Ultimate Response Guideline (URG) to cope with Fukushima-like accidents. The main content of the URG is a two-stage depressurization strategy, namely the controlled depressurization and the emergency depressurization. The technical basis of the two-stage depressurization strategy was discussed in this paper. The effectiveness of the URG was verified by using TRAC/RELAP Advanced Computational Engine (TRACE). Besides, the emergency responses performed by Fukushima Daini nuclear power plant (Fukushima Daini NPP) were found to be very similar to the URG. The consequences of Fukushima Daini NPP somehow demonstrate that the URG is effective for Fukushima

Outline of the Fukushima Daiichi Accident. Lessons Learned and Safety Enhancements

Science.gov (United States)

Hirano, Masashi

2017-09-01

Abstract. On March 11, 2011, an earthquake and subsequent tsunamis off the Pacific coastline of Japan's Tohoku region caused widespread devastation in Japan. As of June 10, 2016, it is reported that a total of 15,894 people lost their lives and 2,558 people are still unaccounted for. In Fukushima Prefecture, approximately 100,000 people are still obliged to live away from their homes due to the earthquake and tsunami as well as the Fukushima Daiichi accident. On the day, the earthquake and tsunami caused severe damages to the Tokyo Electric Power Company (TEPCO)'s Fukushima Daiichi Nuclear Power Station (NPS). All the units in operation, namely Units 1 to 3, were automatically shut down on seismic reactor protection system trips but the earthquake led to the loss of all off-site electrical power supplies to that site. The subsequent tsunami inundated the site up to 4 to 5 m above its ground level and caused, in the end, the loss of core cooling function in Units 1 to 3, resulting in severe core damages and containment vessel failures in these three units. Hydrogen was released from the containment vessels, leading to explosions in the reactor buildings of Units 1, 3 and 4. Radioactive materials were released to the atmosphere and were deposited on the land and in the ocean. One of the most important lessons learned is an importance to prevent such large scale common cause failures due to extreme natural events. This leads to a conclusion that application of the defense-in-depth philosophy be enhanced because the defense-in-depth philosophy has been and continues to be an effective way to account for uncertainties associated with risks. From the human and organizational viewpoints, the final report from the Investigation Committee of the Government pointed out so-called "safety myth" that existed among nuclear operators including TEPCO as well as the government, that serious severe accidents could never occur in nuclear power plants in Japan. After the accident, the

Activities for the remediation of TEPCO's Fukushima Daiichi nuclear power plant

International Nuclear Information System (INIS)

Kinoshita, Hirofumi; Kometani, Yutaka; Asano, Takashi; Ishiwata, Masayuki; Fukasawa, Tetsuo; Tadokoro, Takahiro; Nagumo, Yasushi; Kani, Yuko; Matsui, Tetsuya

2013-01-01

With the aim of fulfilling recovery work for the Fukushima Daiichi NPP, technological efforts have been made for the development of a survey robot system, adequate communication infrastructure technologies, high radiation environment compatible gamma cameras, heavy machinery-type robots (ASTACO-SoRa), remote decontamination devices (AROUNDER), and contaminated waste water treatment system. We have developed a new type of absorbents which remove cesium (Cs) and strontium (Sr) simultaneously at a high removal rate of 99 % or more. We will provide valuable solutions and rational systems for waste water treatment using this developed adsorbent as well as other various adsorbents for the recovery of Fukushima Daiichi NPP

The Fukushima Daiichi Accident. Technical Volume 4/5. Radiological Consequences

International Nuclear Information System (INIS)

2015-08-01

This technical volume describes the consequences associated with radioactivity and radiation from the accident at the Fukushima Daiichi nuclear power plant (NPP) for people and the environment. A number of international organizations have already issued reports on the potential health and environmental consequences of the accident, notably the World Health Organization (WHO) and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The intention of the assessments presented in this volume is to build on their work, using more recent data where available. Quantitative information arising from both personal and environmental monitoring has been provided by the Government of Japan. Section 4.1 provides the best estimates of the magnitude and form of radioactive releases during the accident to the atmosphere and directly into the surrounding sea. It also explains the movement of the discharged radionuclides through air and water and the eventual deposition of the atmospheric activity on land in Japan and other countries worldwide, as well as on the open oceans. The goal is to provide a consolidated repository of information on releases to, and levels of radionuclides in, the environment. Some of this information is used in the analyses in subsequent sections of this volume. Section 4.2 gives an overview of exposures to the main groups of emergency workers at the Fukushima Daiichi NPP, to groups of off-site workers and to members of the public. Where sufficient data are available, average effective dose and thyroid equivalent doses derived from personal measurements are compared with the results of previous assessments for specific locations, population groups and time periods. Section 4.3 summarizes relevant aspects of the system of radiation protection in place at the time of the accident. It includes an overview of the legislation and guidance used to implement the radiation protection framework in Japan. This section also provides a

Precept from the management for the accident of Fukushima daiichi

International Nuclear Information System (INIS)

Miyaushiro, Norihiro

2013-01-01

At 17 hours after the accident of Fukushima Daiichi Nuclear Power Plant due to the Great East Japan Earthquake, National Institute of Radiological Sciences sent the first REMAT (Radiation Emergency Medical Assistance Team) in the 20 km range from the Plant. The team members were confronted by two issues: (1) Medical activities under the infrastructures destructed by a multiple disaster caused by earthquake, tsunami and nuclear accident, which was not presumed. (2) Radiation protection management for dispatched staff. Measures for this situation worked out by activities on the site are presented. (K.Y.)

Current status and future planning of Fukushima Daiichi Nuclear Power Station after Great East Japan earthquake

International Nuclear Information System (INIS)

Inouer, Y.

2012-01-01

Fukushima Daiichi Nuclear Power Station (NPS) clean-up and decommissioning activities require a lot of R and D and careful project management due to its severity of damage. Inability of access inside the reactor and turbine buildings due to harsh environment results in large uncertainties which make the project planning difficult R and R activities will be conducted in parallel with on-site clean-up and maintenance activities. In order to cope with this unprecedented challenge, the government, laboratories, academicians, vendors, manufacturers, and other partners have joined together to support tokyo electric Power Company, Inc (TEPCO). This paper will summarize the current status and mid-and long-term plan for the clean-up and decommissioning of Units 1 to 4 of Fukushima Daiichi NPS as of March, 2012. (Author) 15 refs.

Radiological and geophysical changes around the Fukushima Daiichi Nuclear Power Plant since the accident to the present time

Science.gov (United States)

Kolotkov, Gennady

2013-04-01

Detailed analysis of accidental released of radioactive material from Fukushima Daiichi nuclear power plant has shown that long-lived radionuclides add considerable support for intensity of ion formation. Based on the results of airborne monitoring by MEXT and DOE (total surface deposition of Cs134 and Cs137 inside 80 km zone of Fukushima Daiichi NPP) it has been calculated the spatial distribution of the intensity of ion formation and atmospheric electric conductivity. The evidence of plutonium in the Fukushima radioactive trace allows calculates the concentration of small, intermediate and large ions. The results show the excess of these parameters by several orders of magnitude since the accident to the present time. For example the concentration of small air ion in the area of Chernobyl is 7±2?102 cm-3, the Fukushima Daiichi NPP ones is 1.3?106 cm-3. The difference in the atmospheric bipolar electric conductivity is about 24 fS/m between the Chernobyl and the Fukushima Daiichi ones. The evaluation technique was used after Chernobyl disaster allows to make an analysis of ecological, hygiene requirements and other problems into the troposphere and on the soil intensity of ion formation in the area of Fukushima Daiichi nuclear power plant. The standard ion air differ by four orders of magnitude in the case for Fukushima Daiichi ones. Comparative study of the radiophysical characteristics of the atmosphere with the analogous ones in Chernobyl and application of identification of various types of the air pollution is discussed.

Fukushima-Daiichi after the severe accident (estimation)

International Nuclear Information System (INIS)

Otcenasek, Petr

2011-01-01

All facts about the Fukushima-Daiichi NPP and about the accident known at the time of publication are summarized and expected remedial actions and consequences of the accidents are deduced. The paper is structured as follows: (1) Accident initiation is known; (2) Logically inferred results; (3) Framework identification; (4) Survey; and (5) Economic and strategic impacts of the accident. Worldwide solidarity is mentioned in conclusion. (P.A.)

MDEP Design-Specific Common Position CP-APR1400WG-01. Common position addressing Fukushima Daiichi nuclear power plant accident

International Nuclear Information System (INIS)

2016-05-01

The MDEP APR1400 Working Group (APR1400WG) members consist of members from Republic of Korea, United Arab Emirates, and the United States. A main objectives of MDEP is to encourage convergence of code, standard and safety goals with exploring the opportunities for harmonization of regulatory practice and cooperation on safety review of APR-1400 specific designs. This common position addressing is aimed at sharing knowledge, information and experience on safety improvement related to lessons learned from the Fukushima Daiichi NPP Accident or Fukushima Daiichi NPP Accident-related issues amongst APR-1400 WG member states to achieve the MEDP goal. Because not all of these Regulators have completed the regulatory review of their APR1400 applications yet, this paper identifies common preliminary approaches to address potential safety improvements for APR1400 plants, as well as common general expectations for new nuclear power plants, as related to lessons learned from the Fukushima Daiichi NPP Accident or Fukushima Daiichi NPP Accident-related issues. While some asymmetry exists among those of three Regulators in terms of design, regulatory practice and licensing milestone sharing information and common understanding on post-Fukushima Daiichi NPP Accident enhancement would be promote resilient design for countering beyond design extreme external event like Fukushima Daiichi NPP nuclear disaster. This common position paper aims at identifying characteristics of post-Fukushima Daiichi NPP Accident enhancements putting in place by each country and setting common position to achieve balanced and harmonized APR-1400 design. After the safety reviews of the APR1400 design applications that are currently in review are completed, the regulators will update this paper to reflect their safety conclusions regarding the APR1400 design and how the design could be enhanced to address Fukushima Daiichi NPP Accident-related issues. The common preliminary approaches are organised into

Fukushima-Daiichi accident. News bulletin no. 2 from April 8

International Nuclear Information System (INIS)

2011-01-01

This news bulletin has been prepared by the French institute of radiation protection and nuclear safety (IRSN) for the information of French residents in Japan. It presents, first, the situation at the date of the bulletin of the reactors at the power plant site, the accident management actions in progress, the radioactive contamination around the site, the evolution of radioactivity in the air of Tokyo since March 15, the meteorological forecasts, and the impact of the April 7 earthquake. Then, it gives some general recommendations to residents concerning food consumption and dwelling hygiene. Finally, some scientific information about radionuclides migration, radioactive pollution and their environmental impact are given. The geographic distribution of radioactive fallouts around the Fukushima-Daiichi site is shown. (J.S.)

Lessons learned from the Fukushima Dai-ichi accident and responses in NRA regulatory requirements

International Nuclear Information System (INIS)

Fuketa, Toyoshi

2014-01-01

The author would like to present significant lessons learned from the TEPCO’s Fukushima Dai-ichi accident and responses in regulatory requirements developed by the Nuclear Regulation Authority for power-producing light water reactors. The presentation will cover prevention of structures, systems and components failures, measures to prevent common cause failures, prevention of core damage, mitigation of severe accidents, emergency preparedness, continuous improvement of safety, use of probabilistic risk assessment, and post-accident regulation on the Fukushima Dai-ichi. (author)

Lessons of the Fukushima Dai-ichi accident for PSA

International Nuclear Information System (INIS)

Kumar, M.; Klug, J.; Alzbutas, R.; Burgazzi, L.; Farcasiu, M.; Nitoi, M.; Ivanov, I.; Bogdanov, D.; Hashimoto, K.; Hirata, K.; La Rovere, S.; Sevbo, O.; Vitazkova, J.; Hustak, S.; Wielenberg, A.; Raimond, E.

2016-01-01

The objective of this document is to identify some lessons learned from the Fukushima Dai-ichi accident for PSA. Based on the public information on the causes that have led to major radioactive release during the Fukushima Dai-ichi accident (initiating events, material and human response), the authors, ASAMPSA-E WP30 members have performed a review to examine the gaps/insufficiencies/incompleteness in the existing Level 1 and Level 2 PSAs. This is the aim of this report which is one of WP30 deliverables i.e. D30.2. The consideration of external initiating events for the different levels of defense-in-depth is one of the focal points in this review. Recommendations in the way of developing the different elements of PSAs have been proposed by the authors and were completed later during the ASAMPSA-E project. Moreover, first recommendations on the use of PSA information in decision making have been included as well. (authors)

Groundwater flow modeling focused on the Fukushima Daiichi Nuclear Power Plant Site

International Nuclear Information System (INIS)

Saegusa, Hiromitsu; Onoe, Hironori; Kohashi, Akio; Watanabe, Masahisa

2015-01-01

Fukushima Daiichi nuclear power plant of Tokyo Electric Power Company is facing contaminated water issues in the aftermath of the Great East Japan Earthquake on March 11, 2011. The amount of contaminated water is continuously increasing due to groundwater leakage into the underground part of reactor and turbine buildings. Therefore, it is important to understand the groundwater flow conditions at the site and to predict the impact of countermeasures taken for isolating groundwater from the source of the contamination, i.e. the reactor buildings. Installations, such as of land-side and sea-side impermeable walls have been planned as countermeasures. In this study, groundwater flow modeling has been performed to estimate the response of groundwater flow conditions to the countermeasures. From the modeling, groundwater recharge and discharge areas, major groundwater flow direction, inflow rate into underground part of the buildings, and changes in response to implementation of the countermeasures could be reasonably estimated. The results indicate that the countermeasures will decrease the volume of inflow into the underground part of the buildings. This means that the countermeasures will be effective in reducing the discharge volume of contaminated groundwater to ocean. (author)

Unsolved issues related to thermal-hydraulics in the suppression chamber during Fukushima Daiichi accident progressions

International Nuclear Information System (INIS)

Mizokami, Shinya; Yamada, Daichi; Honda, Takeshi; Yamauchi, Daisuke; Yamanaka, Yasunori

2016-01-01

On 11 March 2011, the Great East Japan Earthquake and Tsunami hit the Fukushima Daiichi Nuclear Power Station. The Fukushima Daiichi Units 1-3 lost all DC and AC power supplies, which set in motion a chain of events that led to releases of radioactivity to the environment. Since then, TEPCO has made many efforts to investigate the accident progressions and the status of the reactors and containment vessels. However, there still exist several tens of unsolved issues to be investigated for the fully understanding of the accident. In this paper, we introduce the unsolved issues related to thermal-hydraulics in the suppression chamber during the Fukushima Daiichi accident progressions. Especially, in Units 2 and 3, there are possibilities that thermal stratification inside their suppression chambers played an important role. It is important that these phenomena are addressed following both theoretical and experimental approaches as support to severe accident simulations. (author)

Applicability of health physics lessons learned from the Three Mile Island Unit 2 accident to the Fukushima Daiichi accident.

Science.gov (United States)

Bevelacqua, J J

2012-02-01

The TMI-2 and Fukushima Daiichi accidents appear to be dissimilar because they involve different reactor types. However, the health physics related lessons learned from TMI-2 are applicable, and can enhance the Fukushima Daiichi recovery effort. Copyright © 2011 Elsevier Ltd. All rights reserved.

Response to the accident at TEPCO's Fukushima Daiichi Nuclear Power Plants

International Nuclear Information System (INIS)

Nei, Hisanori

2012-01-01

This article was reading from the author's plenary lecture at the thermal and nuclear power generation convention 2011, which was summary of the author edited report of Japanese government to IAEA ministerial conference on nuclear safety. The article consisted of (1) outlines of occurrence and development of the accident at TEPCO's Fukushima Daiichi Nuclear Power Plants (NPPs), (2) comparison of Fukushima Daiichi NPPs with other NPPs (Fukushima Daini, Onagawa and Tokai Daini NPPs), (3) major countermeasures to settle the situation regarding the accident, (4) comprehensive safety evaluation of other NPPs as response to the accident and (5) lessons learned from the accident so far. It was highly important to ensure power supplies and robust cooling functions of reactors, pressure containment vessels and spent fuel pools. 28 lessons were categorized into five groups such as (1) strengthen preventive measures against a severe accident, (2) enhancement of response measures against severe accidents, (3) enhancement of nuclear emergency responses, (4) reinforcement of safety infrastructure and (5) thoroughness of safety culture. (T. Tanaka)

Fukushima Daiichi - delivery of contaminated water into the Pacific ocean and possible consequences for the marine ecosystem; Fukushima Daiichi. Ableitungen und deren moegliche Auswirkungen in der Meeresumwelt

Energy Technology Data Exchange (ETDEWEB)

Nies, Hartmut [Bundesamt fuer Seeschifffahrt und Hydrographie (BSH), Hamburg (Germany). Abt. Meereskunde

2015-06-01

The nuclear power plant Fukushima Daiichi is sited at the coast of the Japanese island Honshu. Most of the cooling water for the three destroyed reactors units 1-3 and the nuclear fuel in the spent fuel pool of unit-4 were uncontrolled delivered into the groundwater and the Pacific Ocean. As a consequence high concentrations of I-131, Cs-134 and Cs-137 in the coastal waters have to be assumed. The contribution analyzed the possible consequences for the marine ecosystem. A drift time of 5 to 7 years toward the coast of North America is expected. The planning of the marine monitoring program MEXT is described. Radiation measurements in the coastal water up to 200 km distance from Daiichi were performed. The highest radionuclide concentrations of Cs-137 and Cs-134 were found in the fine grained sediments. No increased radioactivity in seafood is expected.

Decontamination and concrete core sampling by teleoperated robot at Fukushima Daiichi reactor buildings

International Nuclear Information System (INIS)

Watanabe, Masaru; Onitsuka, Hironori; Shimonabe, Noriaki; Fujita, Jun; Matsumura, Takumi; Okumura, Atsushi

2015-01-01

For decommissioning of Fukushima daiichi nuclear power station, reduction of the dose equivalent rates inside the reactor buildings is an important issue. Concrete core sampling from the buildings to investigate the contamination is necessary for study about effective decontamination. However, dose rate inside the reactor buildings is very high. For example, dose rate of 1st floor on the Unit 1 is 1.2 - 1820 [mSv / h], the Unit 2 is 2.5 - 220 [mSv / h] and Unit 3 is 2.2 - 4780 [mSv / h]. So it is difficult for workers to work long hours. Therefore, a teleoperated robot, named 'MHI-MEISTeR (Mitsubishi Heavy Industries - Maintenance Equipment Integrated System of Telecontrol Robot)', has been developed to conduct operations like concrete core samples from the reactor buildings. Actually, some concrete core samples from Fukushima daiichi were taken by MHI-MEISTeR. In addition, MHI-MEISTeR is designed as a versatile robot, and so it can conduct suction / blast decontamination works as well as concrete core sampling. The above operations were performed by MHI-MEISTeR in Fukushima daiichi nuclear power station. (author)

Analysis of accident progression in the TEPCO Fukushima Daiichi Nuclear Power Station

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-08-15

One of the objectives of this study is to investigate the early stage of the TEPCO Fukushima Daiichi accident and to check the validity of the countermeasures against the accident. Last year the early stage of the accident was analyzed with use of RELAP5 code, and the longer term analysis was done by MELCOR code. This year, the simulation of reactor water level instrumentation behavior by MELCOR code was performed. Another objective of this study is to analyze of the long term cooling after the Fukushima Daiichi accident by TRACE5 code. In order to simulate the cooling conditions in Fukushima plants after the accident, the parametric calculations were done on the assumption of the existence of steam/liquid leak in Reactor Pressure Vessel (RPV) and Pressure Containment Vessel (PCV) and the variety of debris distribution in RPV and PCV. As a result, the debris distribution in RPV and PCV was estimated by referring plant parameter such as reactor pressure and temperature. (author)

The Fukushima Daiichi nuclear disaster: a brief report

International Nuclear Information System (INIS)

Yadav, Roopaksh; Joshi, Pankaj Kumar

2012-01-01

Fukushima Daiichi is a series of equipment failures, nuclear meltdown and release of radioactive materials at the Fukushima -1 nuclear power plant, following the Tohoku earthquake and tsunami. The plant comprises six separate boiling water reactors originally designed by general electric and maintained by the Tokyo Electric Power Company (TEPCO). The Fukushima disaster is the building may be causing isolated, uncontrolled nuclear chain reaction. TEPCO confirmed its concern about the accuracy of high iodine and chlorine report by formally retracting the report which eliminated both the exceptionally high iodine-134 and chlorine-38 levels as proof of criticality. Reports of 13 observation of neutron beams 1.5 km. 'southwest of the plant's no. 1 and 2 reactors' from 13 to 16 March raised the possibility the nuclear fission could have occurred after the initial scraming of the reactors at Fukushima Daiichi. 16 March reports that fuel rods in the spent fuel pool at unit 4 could have been exposed to air appeared to indicate the fission may have occurred in that fuel pool. Later reports of exceptionally high iodine-134 levels appeared to confirm this theory because very high levels of iodine-134 would be indicative of fission reactions. The same report also showed high measurements of chlorine-38, which some nuclear experts used to calculate that fission must be occurring in unit 1. Despite TEPCO suggesting the iodine-134 report was inaccurate, the IAEA appeared to accept the chlorine-based analysis as a valid theory suggesting fission when it stated at a press conference that Melted fuel in the no. 1 reactor as of September 2011, there were no deaths or serious injuries due to direct radiation. Cancer deaths due to accumulated radiation exposure cannot be ruled out and according to one expert, might be in the order of 100 cases. (author)

Activities for the remediation of TEPCO's Fukushima Daiichi nuclear power plant

Energy Technology Data Exchange (ETDEWEB)

Kinoshita, Hirofumi; Kometani, Yutaka; Asano, Takashi; Ishiwata, Masayuki; Fukasawa, Tetsuo [Hitachi-GE Nuclear Energy, Ltd., 2-2, Omika-cho, 5-chome, Hitachi-shi Ibaraki-ken, 319-1221 (Japan); Tadokoro, Takahiro; Nagumo, Yasushi; Kani, Yuko; Matsui, Tetsuya [Hitachi Research Laboratory, Hitachi, Ltd. 2-2, Omika-cho, 5-chome, Hitachi-shi Ibaraki-ken, 319-1221 (Japan)

2013-07-01

With the aim of fulfilling recovery work for the Fukushima Daiichi NPP, technological efforts have been made for the development of a survey robot system, adequate communication infrastructure technologies, high radiation environment compatible gamma cameras, heavy machinery-type robots (ASTACO-SoRa), remote decontamination devices (AROUNDER), and contaminated waste water treatment system. We have developed a new type of absorbents which remove cesium (Cs) and strontium (Sr) simultaneously at a high removal rate of 99 % or more. We will provide valuable solutions and rational systems for waste water treatment using this developed adsorbent as well as other various adsorbents for the recovery of Fukushima Daiichi NPP.

Situation of Fukushima Dai-ichi power plant in Japan - June 1, 2011 status

International Nuclear Information System (INIS)

2011-01-01

This situation note is established according to the information gained on June 1, 2011 by the crisis centre of the French institute of radiation protection and nuclear safety (IRSN). The situation of the cores of reactors 1, 2 and 3 of the Fukushima I site (Dai-ichi) and of the different spent fuel pools is briefly presented as well as the actions in progress for the control of environmental radioactive releases and for the progressive recovery of the facilities control. (J.S.)

Situation of Fukushima Dai-ichi power plant in Japan - May 25, 2011 status

International Nuclear Information System (INIS)

2011-01-01

This situation note is established according to the information gained on May 25, 2011 by the crisis centre of the French institute of radiation protection and nuclear safety (IRSN). The situation of the cores of reactors 1, 2 and 3 of the Fukushima I site (Dai-ichi) and of the different spent fuel pools is briefly presented as well as the actions in progress for the control of environmental radioactive releases and for the progressive recovery of the facilities control. (J.S.)

Severe accident management: radiation dose control, Fukushima Daiichi and TMI-2 nuclear plant accidents

International Nuclear Information System (INIS)

Shaw, Roger

2014-01-01

This presentation presents valuable dose information related to the Fukushima Daiichi and Three Mile Island Unit 2 (TMI-2) Nuclear Plant accidents. Dose information is provided for what is well known for TMI-2, and what is available for Fukushima Daiichi. Particular emphasis is placed on the difference between the type of reactors involved, overarching plant damage issues, and radiation worker dose outcomes. For TMI-2, more in depth dose data is available for the accident and the subsequent recovery efforts. The comparisons demonstrate the need to understand the wide variation in potential dose management measures and outcomes for severe reactor accidents. (author)

Situation of Fukushima Dai-ichi power plant in Japan - May 25, 2011 status; Situation de la centrale nucleaire de Fukushima Dai-ichi au Japon - Point de situation du 25 mai 2011

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

This situation note is established according to the information gained on May 25, 2011 by the crisis centre of the French institute of radiation protection and nuclear safety (IRSN). The situation of the cores of reactors 1, 2 and 3 of the Fukushima I site (Dai-ichi) and of the different spent fuel pools is briefly presented as well as the actions in progress for the control of environmental radioactive releases and for the progressive recovery of the facilities control. (J.S.)

Insights Gained from Forensic Analysis with MELCOR of the Fukushima-Daiichi Accidents.

Energy Technology Data Exchange (ETDEWEB)

Andrews, Nathan C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gauntt, Randall O. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-10-01

Since the accidents at Fukushima-Daiichi, Sandia National Laboratories has been modeling these accident scenarios using the severe accident analysis code, MELCOR. MELCOR is a widely used computer code developed at Sandia National Laboratories since ~1982 for the U.S. Nuclear Regulatory Commission. Insights from the modeling of these accidents is being used to better inform future code development and potentially improved accident management. To date, our necessity to better capture in-vessel thermal-hydraulic and ex-vessel melt coolability and concrete interactions has led to the implementation of new models. The most recent analyses, presented in this paper, have been in support of the of the Organization for Economic Cooperation and Development Nuclear Energy Agency’s (OECD/NEA) Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Station (BSAF) Project. The goal of this project is to accurately capture the source term from all three releases and then model the atmospheric dispersion. In order to do this, a forensic approach is being used in which available plant data and release timings is being used to inform the modeled MELCOR accident scenario. For example, containment failures, core slumping events and lower head failure timings are all enforced parameters in these analyses. This approach is fundamentally different from a blind code assessment analysis often used in standard problem exercises. The timings of these events are informed by representative spikes or decreases in plant data. The combination of improvements to the MELCOR source code resulting from analysis previous accident analysis and this forensic approach has allowed Sandia to generate representative and plausible source terms for all three accidents at Fukushima Daiichi out to three weeks after the accident to capture both early and late releases. In particular, using the source terms developed by MELCOR, the MACCS software code, which models atmospheric dispersion and

Addenda to the second update of the Fukushima Daiichi Nuclear Power Station accident. June 1 to August 31, 2011

International Nuclear Information System (INIS)

2011-01-01

These addenda provide the figures and tables for helping readers to understand the article titled 'the second update of the Fukushima Daiichi Nuclear Power Station (NPS) accident' by SHIBUTANI Yu. These figures and tables are mainly referred from 'Additional Report of the Japanese Government to the IAEA - The Accident at the Tokyo Electric Power Company Inc. (TEPCO) Fukushima Daiichi NPS - September 2011, Nuclear Emergency Response Headquarters Government of Japan' and the website of Prime Minster of Japan and His Cabinet, Nuclear and Industrial Safety Agency (NISA), Ministry of Education, Culture, Sports, Science and Technology (MEXT), TEPCO and Japan Atomic Industrial Forum Inc. (JAIF). The contents of this addenda cover (1) summary of 28 learned lessons, (2) status of each unit of Fukushima Daiichi NPS, (3) alternative core cooling system, (4) spent fuel pool alternative cooling system, (5) outline of waste water storage and treatment system, (6) prevention of environmental release of radioactive materials and monitoring, (7) environmental effect caused by the accident, and (8) influence of Fukushima Daiichi accident on electricity supply in Japan. (author)

Multi-Phased, Post-Accident Support of the Fukushima Dai-Ichi Nuclear Power Plant - 12246

Energy Technology Data Exchange (ETDEWEB)

Gay, Arnaud; Gillet, Philippe; Ytournel, Bertrand; Varet, Thierry; David, Laurent; Prevost, Thierry; Redonnet, Carol; Piot, Gregoire; Jouaville, Stephane; Pagis, Georges [AREVA NC (France)

2012-07-01

In the wake of the March 11 earthquake and tsunami and the subsequent flooding of several of the Fukushima Dai-Ichi reactors, Japan and the Japanese utility TEPCO faced a crisis situation with incredible challenges: substantial amounts of radioactive mixed seawater and freshwater accumulated in the basements of four reactor and other buildings on the site. This water held varying levels of contamination due to the fact that it had been in contact with damaged fuel elements in the cores and with other contaminated components. The overall water inventory was estimated at around 110,000 tons of water with contamination levels up to the order of 1 Ci/l. Time was of the essence to avoid overflow of this accumulated water into the ocean. AREVA proposed, designed and implemented a water treatment solution using a proven chemical coprecipitation process with ppFeNi reagent, which is currently in use for effluent treatment on several nuclear sites including AREVA sites. In addition to the extremely short schedule the other challenge was to adapt the chemical treatment process to the expected composition of the Fukushima water and, in particular, to evaluate the impact of salinity on process performance. It was also necessary to define operating conditions for the VEOLIA equipment that had been selected for implementation of the process in the future facility. The operation phase began on June 17, and by the end of July more than 30,000 tons of highly radioactive saltwater had been decontaminated - the Decontamination Factor (DF) for Cesium was ∼10{sup 4}. It allowed recycling the contaminated water to cool the reactors while protecting workers and the environment. This paper focuses on the Actiflo{sup TM}-Rad water treatment unit project that was part of the TEPCO general water treatment scheme. It presents a detailed look at the principles of the Actiflo{sup TM}-Rad, related on-the-fly R and D, an explanation of system implementation challenges, and a brief summary of

Effect of evacuation on liver function after the Fukushima Daiichi Nuclear Power Plant accident: The Fukushima Health Management Survey.

Science.gov (United States)

Takahashi, Atsushi; Ohira, Tetsuya; Hosoya, Mitsuaki; Yasumura, Seiji; Nagai, Masato; Ohira, Hiromasa; Hashimoto, Shigeatsu; Satoh, Hiroaki; Sakai, Akira; Ohtsuru, Akira; Kawasaki, Yukihiko; Suzuki, Hitoshi; Kobashi, Gen; Ozasa, Kotaro; Yamashita, Shunichi; Kamiya, Kenji; Abe, Masafumi

2017-04-01

The Great East Japan Earthquake and subsequent Fukushima Daiichi Nuclear Power Plant accident caused residents to switch from their normal lives to lives focused on evacuation. We evaluated liver function before and after this disaster to elucidate the effects of evacuation on liver function. This study was a longitudinal survey of 26,006 Japanese men and women living near the Fukushima Daiichi Nuclear Power Plant. This study was undertaken using data from annual health checkups conducted for persons aged 40-90 years between 2008 and 2010. Follow-up examinations were conducted from June 2011 to the end of March 2013, with a mean follow up of 1.6 years. Changes in liver function before and after the disaster were compared among evacuees and non-evacuees. We also assessed groups according to alcohol drinking status. The prevalence of liver dysfunction significantly increased in all participants from 16.4% before to 19.2% after the disaster. The incidence of liver dysfunction was significantly higher in evacuees than in non-evacuees. Multivariate logistic regression analysis showed that evacuation was significantly associated with liver dysfunction among residents. This is the first study to show that evacuation due to the Fukushima Daiichi nuclear power plant disaster was associated with an increase in liver dysfunction. Copyright © 2016 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

Situation of Fukushima Dai-ichi power plant in Japan - June 1, 2011 status; Situation de la centrale nucleaire de Fukushima Dai-ichi au Japon - Point de situation du 1er juin 2011

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

This situation note is established according to the information gained on June 1, 2011 by the crisis centre of the French institute of radiation protection and nuclear safety (IRSN). The situation of the cores of reactors 1, 2 and 3 of the Fukushima I site (Dai-ichi) and of the different spent fuel pools is briefly presented as well as the actions in progress for the control of environmental radioactive releases and for the progressive recovery of the facilities control. (J.S.)

Risk communication with Fukushima residents affected by the Fukushima Daiichi accident at whole-body counting

Energy Technology Data Exchange (ETDEWEB)

Gunji, I.; Furuno, A.; Yonezawa, R.; Sugiyama, K. [Risk Communication Study Office, Japan Atomic Energy Agency 4-33 Muramatsu, Tokai-mura, Ibaraki, 319-1194 (Japan)

2013-07-01

After the Tokyo Electric Power Company (TEPCO) Fukushima Daiichi nuclear power plant accident, the Tokai Research and Development Center of the Japan Atomic Energy Agency (JAEA) have had direct dialogue as risk communication with Fukushima residents who underwent whole-body counting examination (WBC). The purpose of the risk communication was to exchange information and opinions about radiation in order to mitigate Fukushima residents' anxiety and stress. Two kinds of opinion surveys were performed: one survey evaluated residents' views of the nuclear accident itself and the second survey evaluated the management of WBC examination as well as the quality of JAEA's communication skills on risks. It appears that most Fukushima residents seem to have reduced their anxiety level after the direct dialogue. The results of the surveys show that Fukushima residents have the deepest anxiety and concern about their long-term health issues and that they harbor anger toward the government and TEPCO. On the other hand, many WBC patients and patients' relatives have expressed gratitude for help in reducing their feelings of anxiety.

Risk communication with Fukushima residents affected by the Fukushima Daiichi accident at whole-body counting

International Nuclear Information System (INIS)

Gunji, I.; Furuno, A.; Yonezawa, R.; Sugiyama, K.

2013-01-01

After the Tokyo Electric Power Company (TEPCO) Fukushima Daiichi nuclear power plant accident, the Tokai Research and Development Center of the Japan Atomic Energy Agency (JAEA) have had direct dialogue as risk communication with Fukushima residents who underwent whole-body counting examination (WBC). The purpose of the risk communication was to exchange information and opinions about radiation in order to mitigate Fukushima residents' anxiety and stress. Two kinds of opinion surveys were performed: one survey evaluated residents' views of the nuclear accident itself and the second survey evaluated the management of WBC examination as well as the quality of JAEA's communication skills on risks. It appears that most Fukushima residents seem to have reduced their anxiety level after the direct dialogue. The results of the surveys show that Fukushima residents have the deepest anxiety and concern about their long-term health issues and that they harbor anger toward the government and TEPCO. On the other hand, many WBC patients and patients' relatives have expressed gratitude for help in reducing their feelings of anxiety

JANSI’s Activities for Reflecting Lessons Learned from Fukushima Daiichi Accident

International Nuclear Information System (INIS)

Kugo, Akihide

2014-01-01

Conclusion: JANSI will continue to lay the groundwork for preventing an accident like the Fukushima Daiichi from ever happening again. JANSI will develop the system to provide an opportunity of “awareness” for operators to enhance nuclear safety and to follow-up their efforts continuously

Impacts of the Fukushima Daiichi Accident on Nuclear Development Policies

International Nuclear Information System (INIS)

Vance, Robert; Henderson, David; ); Moore, Laurie

2017-01-01

The Fukushima Daiichi nuclear power plant accident has had an impact on the development of nuclear power around the world. While the accident was followed by thorough technical assessments of the safety of all operating nuclear power plants, and a general increase in safety requirements has been observed worldwide, national policy responses have been more varied. These responses have ranged from countries phasing out or accelerating decisions to phase out nuclear energy to countries reducing their reliance on nuclear power or on the contrary continuing to pursue or expand their nuclear power programs. This study examines changes to policies, and plans and attempts to distinguish the impact of the Fukushima Daiichi accident from other factors that have affected policy-making in relation to nuclear energy, in particular electricity market economics, financing challenges and competition from other sources (gas, coal and renewables). It also examines changes over time to long-term, quantitative country projections, which reveal interesting trends on the possible role of nuclear energy in future energy systems. (authors)

Research and development towards decommissioning of Fukushima Daiichi Nuclear Power Plants

International Nuclear Information System (INIS)

Minato, Kazuo

2013-01-01

Towards the decommissioning of Fukushima Daiichi Nuclear Power Plants, science-based research and development is important and useful, as well as technology and engineering development. Research and development activities based on radiation chemistry, radiochemistry, thermodynamics, etc., have contributed to safe and efficient decommissioning of the plants. (author)

Peace Education, Domestic Tranquility, and Democracy: The Fukushima Daiichi Nuclear Disaster as Domestic Violence

Science.gov (United States)

Ide, Kanako

2014-01-01

This article is an attempt to develop a theory of peace education through an examination of the Fukushima Daiichi nuclear disaster. It examines why Japan did not avoid this terrible nuclear disaster. This is an educational issue, because one of the major impacts of Fukushima's catastrophe is that it indicates the failure of peace education. In…

NEA support to Fukushima Daiichi decommissioning strategy planning

International Nuclear Information System (INIS)

Weber, Inge; Otsuka, Ichiro; ); Sandberg, Nils; ); Funaki, Kentaro

2017-01-01

Six years after the Fukushima Daiichi nuclear power plant accident, the Japanese government and Tokyo Electric Power Holdings, Inc. (TEPCO) are shifting their focus to strategy planning for long-term challenges related to the decommissioning of the damaged reactors. The international community has been helping to address the unprecedented challenges of managing the accident facilities. The NEA is playing a key supporting and coordinating role in the international community, in particular in the area of radioactive waste management and the evaluation of the conditions and location of fuel debris. In the first half of 2017, a series of visual investigations using remotely controlled equipment and robots were performed to identify the condition of vessels inside, as well as the distribution of fuel debris in all three units. In the summer of 2017, as stated in the government road-map, policies for fuel debris retrieval from each unit would be presented, and would result in a discussion on which unit should be the first to undergo fuel debris retrieval in 2018. In addition, the basic policy for the processing and disposal of radioactive material arising from the accident would be conceptualised in the year 2017. This article highlights ongoing international joint activities within the NEA framework, corresponding to the challenges that have been identified in the Fukushima Daiichi decommissioning strategy planning

Removal of Radionuclides from Waste Water at Fukushima Daiichi Nuclear Power Plant: Desalination and Adsorption Methods - 13126

Energy Technology Data Exchange (ETDEWEB)

Kani, Yuko; Kamosida, Mamoru; Watanabe, Daisuke [Hitachi Research Laboratory, Hitachi, Ltd., 7-2-1 Omika-cho, Hitachi, Ibaraki, 319-1221 (Japan); Asano, Takashi; Tamata, Shin [Hitachi Works, Hitachi-GE Nuclear Energy, Ltd. (Japan)

2013-07-01

Waste water containing high levels of radionuclides due to the Fukushima Daiichi Nuclear Power Plant accident, has been treated by the adsorption removal and reverse-osmosis (RO) desalination to allow water re-use for cooling the reactors. Radionuclides in the waste water are collected in the adsorbent medium and the RO concentrate (RO brine) in the water treatment system currently operated at the Fukushima Daiichi site. In this paper, we have studied the behavior of radionuclides in the presently applied RO desalination system and the removal of radionuclides in possible additional adsorption systems for the Fukushima Daiichi waste water treatment. Regarding the RO desalination system, decontamination factors (DFs) of the elements present in the waste water were obtained by lab-scale testing using an RO unit and simulated waste water with non-radioactive elements. The results of the lab-scale testing using representative elements showed that the DF for each element depended on its hydrated ionic radius: the larger the hydrated ionic radius of the element, the higher its DF is. Thus, the DF of each element in the waste water could be estimated based on its hydrated ionic radius. For the adsorption system to remove radionuclides more effectively, we studied adsorption behavior of typical elements, such as radioactive cesium and strontium, by various kinds of adsorbents using batch and column testing. We used batch testing to measure distribution coefficients (K{sub d}s) for cesium and strontium onto adsorbents under different brine concentrations that simulated waste water conditions at the Fukushima Daiichi site. For cesium adsorbents, K{sub d}s with different dependency on the brine concentration were observed based on the mechanism of cesium adsorption. As for strontium, K{sub d}s decreased as the brine concentration increased for any adsorbents which adsorbed strontium by intercalation and by ion exchange. The adsorbent titanium oxide had higher K{sub d}s and it

Removal of Radionuclides from Waste Water at Fukushima Daiichi Nuclear Power Plant: Desalination and Adsorption Methods - 13126

International Nuclear Information System (INIS)

Kani, Yuko; Kamosida, Mamoru; Watanabe, Daisuke; Asano, Takashi; Tamata, Shin

2013-01-01

Waste water containing high levels of radionuclides due to the Fukushima Daiichi Nuclear Power Plant accident, has been treated by the adsorption removal and reverse-osmosis (RO) desalination to allow water re-use for cooling the reactors. Radionuclides in the waste water are collected in the adsorbent medium and the RO concentrate (RO brine) in the water treatment system currently operated at the Fukushima Daiichi site. In this paper, we have studied the behavior of radionuclides in the presently applied RO desalination system and the removal of radionuclides in possible additional adsorption systems for the Fukushima Daiichi waste water treatment. Regarding the RO desalination system, decontamination factors (DFs) of the elements present in the waste water were obtained by lab-scale testing using an RO unit and simulated waste water with non-radioactive elements. The results of the lab-scale testing using representative elements showed that the DF for each element depended on its hydrated ionic radius: the larger the hydrated ionic radius of the element, the higher its DF is. Thus, the DF of each element in the waste water could be estimated based on its hydrated ionic radius. For the adsorption system to remove radionuclides more effectively, we studied adsorption behavior of typical elements, such as radioactive cesium and strontium, by various kinds of adsorbents using batch and column testing. We used batch testing to measure distribution coefficients (K d s) for cesium and strontium onto adsorbents under different brine concentrations that simulated waste water conditions at the Fukushima Daiichi site. For cesium adsorbents, K d s with different dependency on the brine concentration were observed based on the mechanism of cesium adsorption. As for strontium, K d s decreased as the brine concentration increased for any adsorbents which adsorbed strontium by intercalation and by ion exchange. The adsorbent titanium oxide had higher K d s and it was used for

Evaluation of re-criticality potential in Fukushima Dai-ichi reactors following core damage accidents

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-08-15

The re-criticality potential of the debris-bed, formed of the degraded core materials, cannot be ruled out during the cooling-down procedure of the Fukushima Dai-ichi NPPs. In this study the re-criticality potential has systematically investigated based on the core disruption phase analysis using a IMPACT-SAMPSON code prepared by The Institute of Applied Energy (IAE). The results obtained for the re-criticality potential, characterized by the eigen-values k-eff dependent on the debris composition formed at the core, RPV bottom, and PCV pedestal, are reflected to the arguments on the re-criticality prevention measures, such as timing and concentration of boron-compounds, during the cooling-down process of the Fukushima Dai-ichi NPPs. (author)

IAEA International Peer Review Mission on Mid-and-Long-Term Roadmap Towards the Decommissioning of TEPCO's Fukushima Daiichi Nuclear Power Station Units 1-4, Tokyo and Fukushima Prefecture, Japan, 15-22 April 2013. Mission Report

International Nuclear Information System (INIS)

2013-01-01

Following the accident at TEPCO's Fukushima Daiichi Nuclear Power Station (NPS) on 11 March 2011, the ''Mid-and-Long-Term Roadmap towards the Decommissioning of TEPCO's Fukushima Daiichi Nuclear Power Station Units 1-4'' was adopted by the Government of Japan and TEPCO Council on Mid-to-Long-Term Response for Decommissioning in December 2011 and revised in July 2012. The Roadmap, which is scheduled for an additional update in June 2013, describes the main steps and activities to be implemented for the decommissioning of the Fukushima Daiichi NPS through the combined efforts of the Government of Japan and TEPCO. Within the framework of the IAEA Action Plan on Nuclear Safety, the Government of Japan invited the IAEA to conduct an independent peer review of the Roadmap with two main objectives: - To improve the decommissioning planning and the implementation of pre-decommissioning activities at TEPCO's Fukushima Daiichi NPS; and - To share with the international community the good practices and lessons learned by the review. The review has been organized in two steps, and the IAEA conducted the first part in Japan from 15 to 22 April 2013. The objective of the first mission was to undertake an initial review of the Roadmap, including assessments of decommissioning strategy, planning and timing of decommissioning phases and a review of several specific short-term issues and recent challenges. Specifically, it covered the assessment of current reactor conditions, assessment of management of radioactive releases and associated doses, control of radioactive exposure of employees and decontamination within the site for improvement of working environment, structural integrity of reactor buildings and other constructions. The incidents recently experienced at the site, related with failures of the power supply and leakages of water from the underground reservoirs, were also included in the review of the specific short-term issues. The Government of Japan and TEPCO have

National radiological emergency response to the Fukushima Daiichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Dela Rosa, Alumanda M.

2011-01-01

The Fukushima nuclear power plant accident occurred on March 11, 2011, when two natural disasters of unprecedented strengths, an earthquake with magnitude 9 followed one hour later by a powerful tsunami struck northeastern Japan and felled the external power supply and the emergency diesel generators of the Fukushima Daiichi nuclear power station, resulting in a loss of coolant accident. There were core meltdowns in three nuclear reactors with the release of radioactivity estimated to be 1/10 of what was released to the environment during the Chernobyl nuclear power plant accident in April 1986. The Fukushima nuclear accident tested the capability of the Philippine Nuclear Research Institute (PNRI) and the National Disaster Risk Reduction and Management Council (NDRRMC) in responding to such radiological emergency as a nuclear power plant accident. The PNRI and NDRRMC activated the RADPLAN for possible radiological emergency. The emergency response was calibrated to the status of the nuclear reactors on site and the environmental monitoring undertaken around the site and off-site, including the marine environment. This orchestrated effort enabled the PNRI and the national agencies concerned to reassure the public that the nuclear accident does not have a significant impact on the Philippines, both on the health and safety of the people and on the safety of the environment. National actions taken during the accident will be presented. The role played by the International Atomic Energy Agency as the central UN agency for nuclear matters will be discussed. (author)

MDEP Design-Specific Common Position CP-EPRWG-02. Common position addressing Fukushima Daiichi-related issues

International Nuclear Information System (INIS)

2015-10-01

A severe accident involving several units took place in Japan at Fukushima Daiichi nuclear power plant (NPP) in March 2011. The immediate cause of the accident was an earthquake followed by a tsunami coupled with inadequate provisions against the consequences of such events in the design. Opportunities to improve protection against a realistic design basis tsunami were not taken. As a consequence of the tsunami, safety equipment and the related safety functions were lost at the plant, leading to core damage in three units and subsequently to large radioactive releases (INES 7). Several studies have already been performed to better understand the accident progression and detailed technical studies are still in progress in Japan and elsewhere. In the meantime, on-going studies on the behaviour of NPPs in very severe situations, similar to Fukushima Daiichi, seek to identify potential vulnerabilities in plant design and operation; to suggest reasonably practicable upgrades; or to recommend enhanced regulatory requirements and guidance to address such situations. Likewise, agencies around the world that are responsible for regulating the design, construction and operation of EPR plants are engaged in similar activities. The MDEP EPR Working Group (EPRWG) members consist of members from the United States, the United Kingdom, France, Finland, China, India and Sweden. Because not all of these countries have completed the regulatory review of their EPR applications yet, this paper identifies common preliminary approaches to address potential safety improvements for EPR plants, as well as common general expectations for new nuclear power plants, as related to lessons learned from the Fukushima Daiichi accident or Fukushima Daiichi-related issues. After the safety reviews of the EPR design applications that are currently in review are completed, the regulators will update this paper to reflect their safety conclusions regarding the EPR design and how the design could be

Feature article. Fukushima Daiichi NPP accident

International Nuclear Information System (INIS)

Ekarinai, Masashi; Ake, Yutaka; Narabayashi, Tadashi

2011-01-01

This special feature article consisted of five reports and the minutes of emergency discussion meeting on Fukushima Daiichi Nuclear Power Plant (NPP) accident. Effects of the accident on future electricity supply of electric utilities and also on business development of nuclear industries were discussed. Activities of senior network team of atomic energy society of Japan (AESJ) to conduct severe accident analysis and early restoration from the accident were introduced. Circulating injection reactor cooling system and zeolite decontamination system of accumulated contaminated water was proposed. Effects of the accident on overseas reaction on nuclear development were also reported as well as personal experience of the professor in the US west coast on communications. (T. Tanaka)

A comparison of responses to the Fukushima Daiichi Nuclear Plant

International Nuclear Information System (INIS)

Oshima, Teruo

2011-01-01

Many Institutions abroad have expressed their views on the Fukushima Daiichi Nuclear Power Plant accident. When more emphasis on risk and precaution, they differ markedly from that in Japan. One of the main causes of the accident lies in disregard for prior warnings about possible tsunami risks. This paper will discuss lessons we can learn from the accident and future problems. (author)

NIRS external dose estimation system for Fukushima residents after the Fukushima Dai-ichi NPP accident

Science.gov (United States)

Akahane, Keiichi; Yonai, Shunsuke; Fukuda, Shigekazu; Miyahara, Nobuyuki; Yasuda, Hiroshi; Iwaoka, Kazuki; Matsumoto, Masaki; Fukumura, Akifumi; Akashi, Makoto

2013-04-01

The great east Japan earthquake and subsequent tsunamis caused Fukushima Dai-ichi Nuclear Power Plant (NPP) accident. National Institute of Radiological Sciences (NIRS) developed the external dose estimation system for Fukushima residents. The system is being used in the Fukushima health management survey. The doses can be obtained by superimposing the behavior data of the residents on the dose rate maps. For grasping the doses, 18 evacuation patterns of the residents were assumed by considering the actual evacuation information before using the survey data. The doses of the residents from the deliberate evacuation area were relatively higher than those from the area within 20 km radius. The estimated doses varied from around 1 to 6 mSv for the residents evacuated from the representative places in the deliberate evacuation area. The maximum dose in 18 evacuation patterns was estimated to be 19 mSv.

Preliminary Assessment of the Possible BWR Core/Vessel Damage States for Fukushima Daiichi Station Blackout Scenarios Using RELAP/SCDAPSIM

Directory of Open Access Journals (Sweden)

C. M. Allison

2012-01-01

Full Text Available Immediately after the accident at Fukushima Daiichi, Innovative Systems Software and other members of the international SCDAP Development and Training Program started an assessment of the possible core/vessel damage states of the Fukushima Daiichi Units 1–3. The assessment included a brief review of relevant severe accident experiments and a series of detailed calculations using RELAP/SCDAPSIM. The calculations used a detailed RELAP/SCDAPSIM model of the Laguna Verde BWR vessel and related reactor cooling systems. The Laguna Verde models were provided by the Comision Nacional de Seguridad Nuclear y Salvaguardias, the Mexican nuclear regulatory authority. The initial assessment was originally presented to the International Atomic Energy Agency on March 21 to support their emergency response team and later to our Japanese members to support their Fukushima Daiichi specific analysis and model development.

Influence on UK Nuclear Regulation from the Fukushima Daiichi Accident

International Nuclear Information System (INIS)

Savage, R.

2016-01-01

This paper provides an overview of the UKs response to the Fukushima Daiichi Accident and highlights the influence that this has had on UK nuclear regulation since March 2011. ONR’s Incident Suite was staffed from the first day of the accident and remained active on a 24 hours basis for over two weeks. The purpose was to provide advice to the UK government specifically prompt assurance of why this accident couldn’t take place in the UK and practical advice in relation to the 17,000 UK nationals in Japan at that time. In the early phase of the accident ONR took part in international cooperation with the US, Canadian and French regulators in order to determine the actual technical status of the Fukushima Daiichi power plant units. The UK Secretary of State requested that the ONR Chief Inspector identify any lessons to be learnt by the UK nuclear industry and in doing so cooperate and coordinate with international colleagues. The Interim report was produced (May 2011) this focused on civil NPP’s, provided background to radiation, technology and regulations. This report compared the Japan situation with the UK and identified 11 conclusions and 26 recommendations.

Atmospheric radionuclides from the Fukushima Dai-ichi nuclear reactor accident observed in Vietnam

International Nuclear Information System (INIS)

Long, N.Q.; Giap, T.V.; Phan, N.T.; Truong, Y.; Binh, N.T; Sieu, L.N.; Hien, P.D.

2012-01-01

Radionuclides from the reactor accident at the Fukushima Dai-ichi Nuclear Power Plant were observed in the surface air at stations in Hanoi, Dalat and Ho Chi Minh City (HCMC) in Vietnam, about 4500 km southwest of Japan, during the period from March 27 to April 22, 2011. The maximum activity concentrations in the air measured at those three sites were 193, 33 and 37 μBq m -3 for 131 I, 134 Cs and 137 Cs, respectively. Peaks of radionuclide concentrations in the air corresponded to arrival of the air mass from Fukushima to Vietnam after traveling for 8 days over the Pacific Ocean. Cesium-134 was detected with the 134 Cs/ 137 Cs activity ratio of about 0.85 in line with observations made elsewhere. The 131 I/ 137 Cs activity ratio was observed to decrease exponentially with time as expected from radioactive decay. The ratio at Dalat, where is 1500 m high, was higher than those at Hanoi and HCMC in low lands, indicating the relative enrichment of the iodine in comparison to cesium at high altitudes. The time-integrated surface air concentrations of the Fukushima-derived radionuclides in the Southeast Asia showed exponential decrease with distance from Fukushima. (author)

The Fukushima Daiichi Accident. Report by the Director General [Chinese Version

International Nuclear Information System (INIS)

2015-08-01

This report presents an assessment of the causes and consequences of the accident at the Fukushima Daiichi nuclear power plant in Japan, which began on 11 March 2011. Caused by a huge tsunami that followed a massive earthquake, it was the worst accident at a nuclear power plant since the Chernobyl disaster in 1986. The report considers human, organizational and technical factors, and aims to provide an understanding of what happened, and why, so that the necessary lessons learned can be acted upon by governments, regulators and nuclear power plant operators throughout the world. Measures taken in response to the accident, both in Japan and internationally, are also examined. The Fukushima Daiichi Accident consists of a Report by the IAEA Director General and five technical volumes. It is the result of an extensive international collaborative effort involving five working groups with about 180 experts from 42 Member States with and without nuclear power programmes and several international bodies. It provides a description of the accident and its causes, evolution and consequences, based on the evaluation of data and information from a large number of sources available at the time of writing. The Fukushima Daiichi Accident will be of use to national authorities, international organizations, nuclear regulatory bodies, nuclear power plant operating organizations, designers of nuclear facilities and other experts in matters relating to nuclear power, as well as the wider public. The set contains six printed parts and five supplementary CD-ROMs. Contents: Report by the Director General; Technical Volume 1/5, Description and Context of the Accident; Technical Volume 2/5, Safety Assessment; Technical Volume 3/5, Emergency Preparedness and Response; Technical Volume 4/5, Radiological Consequences; Technical Volume 5/5, Post-accident Recovery; Annexes. The Report by the Director General is also available separately in Arabic, Chinese, English, French, Russian, Spanish and

The Fukushima Daiichi Accident. Report by the Director General [Japanese Version

International Nuclear Information System (INIS)

2015-08-01

This report presents an assessment of the causes and consequences of the accident at the Fukushima Daiichi nuclear power plant in Japan, which began on 11 March 2011. Caused by a huge tsunami that followed a massive earthquake, it was the worst accident at a nuclear power plant since the Chernobyl disaster in 1986. The report considers human, organizational and technical factors, and aims to provide an understanding of what happened, and why, so that the necessary lessons learned can be acted upon by governments, regulators and nuclear power plant operators throughout the world. Measures taken in response to the accident, both in Japan and internationally, are also examined. The Fukushima Daiichi Accident consists of a Report by the IAEA Director General and five technical volumes. It is the result of an extensive international collaborative effort involving five working groups with about 180 experts from 42 Member States with and without nuclear power programmes and several international bodies. It provides a description of the accident and its causes, evolution and consequences, based on the evaluation of data and information from a large number of sources available at the time of writing. The Fukushima Daiichi Accident will be of use to national authorities, international organizations, nuclear regulatory bodies, nuclear power plant operating organizations, designers of nuclear facilities and other experts in matters relating to nuclear power, as well as the wider public. The set contains six printed parts and five supplementary CD-ROMs. Contents: Report by the Director General; Technical Volume 1/5, Description and Context of the Accident; Technical Volume 2/5, Safety Assessment; Technical Volume 3/5, Emergency Preparedness and Response; Technical Volume 4/5, Radiological Consequences; Technical Volume 5/5, Post-accident Recovery; Annexes. The Report by the Director General is also available separately in Arabic, Chinese, English, French, Russian, Spanish and

The Fukushima Daiichi Accident. Report by the Director General [Spanish Version

International Nuclear Information System (INIS)

2015-08-01

This report presents an assessment of the causes and consequences of the accident at the Fukushima Daiichi nuclear power plant in Japan, which began on 11 March 2011. Caused by a huge tsunami that followed a massive earthquake, it was the worst accident at a nuclear power plant since the Chernobyl disaster in 1986. The report considers human, organizational and technical factors, and aims to provide an understanding of what happened, and why, so that the necessary lessons learned can be acted upon by governments, regulators and nuclear power plant operators throughout the world. Measures taken in response to the accident, both in Japan and internationally, are also examined. The Fukushima Daiichi Accident consists of a Report by the IAEA Director General and five technical volumes. It is the result of an extensive international collaborative effort involving five working groups with about 180 experts from 42 Member States with and without nuclear power programmes and several international bodies. It provides a description of the accident and its causes, evolution and consequences, based on the evaluation of data and information from a large number of sources available at the time of writing. The Fukushima Daiichi Accident will be of use to national authorities, international organizations, nuclear regulatory bodies, nuclear power plant operating organizations, designers of nuclear facilities and other experts in matters relating to nuclear power, as well as the wider public. The set contains six printed parts and five supplementary CD-ROMs. Contents: Report by the Director General; Technical Volume 1/5, Description and Context of the Accident; Technical Volume 2/5, Safety Assessment; Technical Volume 3/5, Emergency Preparedness and Response; Technical Volume 4/5, Radiological Consequences; Technical Volume 5/5, Post-accident Recovery; Annexes. The Report by the Director General is also available separately in Arabic, Chinese, English, French, Russian, Spanish and

The Fukushima Daiichi Accident. Report by the Director General [Russian Version

International Nuclear Information System (INIS)

2015-08-01

This report presents an assessment of the causes and consequences of the accident at the Fukushima Daiichi nuclear power plant in Japan, which began on 11 March 2011. Caused by a huge tsunami that followed a massive earthquake, it was the worst accident at a nuclear power plant since the Chernobyl disaster in 1986. The report considers human, organizational and technical factors, and aims to provide an understanding of what happened, and why, so that the necessary lessons learned can be acted upon by governments, regulators and nuclear power plant operators throughout the world. Measures taken in response to the accident, both in Japan and internationally, are also examined. The Fukushima Daiichi Accident consists of a Report by the IAEA Director General and five technical volumes. It is the result of an extensive international collaborative effort involving five working groups with about 180 experts from 42 Member States with and without nuclear power programmes and several international bodies. It provides a description of the accident and its causes, evolution and consequences, based on the evaluation of data and information from a large number of sources available at the time of writing. The Fukushima Daiichi Accident will be of use to national authorities, international organizations, nuclear regulatory bodies, nuclear power plant operating organizations, designers of nuclear facilities and other experts in matters relating to nuclear power, as well as the wider public. The set contains six printed parts and five supplementary CD-ROMs. Contents: Report by the Director General; Technical Volume 1/5, Description and Context of the Accident; Technical Volume 2/5, Safety Assessment; Technical Volume 3/5, Emergency Preparedness and Response; Technical Volume 4/5, Radiological Consequences; Technical Volume 5/5, Post-accident Recovery; Annexes. The Report by the Director General is also available separately in Arabic, Chinese, English, French, Russian, Spanish and

Fukushima Daiichi Unit 1 Accident Progression Uncertainty Analysis and Implications for Decommissioning of Fukushima Reactors - Volume I.

Energy Technology Data Exchange (ETDEWEB)

Gauntt, Randall O. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mattie, Patrick D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-01-01

Sandia National Laboratories (SNL) has conducted an uncertainty analysis (UA) on the Fukushima Daiichi unit (1F1) accident progression with the MELCOR code. The model used was developed for a previous accident reconstruction investigation jointly sponsored by the US Department of Energy (DOE) and Nuclear Regulatory Commission (NRC). That study focused on reconstructing the accident progressions, as postulated by the limited plant data. This work was focused evaluation of uncertainty in core damage progression behavior and its effect on key figures-of-merit (e.g., hydrogen production, reactor damage state, fraction of intact fuel, vessel lower head failure). The primary intent of this study was to characterize the range of predicted damage states in the 1F1 reactor considering state of knowledge uncertainties associated with MELCOR modeling of core damage progression and to generate information that may be useful in informing the decommissioning activities that will be employed to defuel the damaged reactors at the Fukushima Daiichi Nuclear Power Plant. Additionally, core damage progression variability inherent in MELCOR modeling numerics is investigated.

Analysis of comparative English media reports about the aftermath of the Fukushima Daiichi Nuclear Power Plant disaster

International Nuclear Information System (INIS)

Sakai, Makoto

2015-01-01

I performed a comparative analysis of media reports that related to the aftermath of the Fukushima Daiichi nuclear power plant disaster. I researched advanced countries' media reports on the nuclear power technology field, and especially those from the United States, the United Kingdom, Germany, and France. For this research, I gathered news texts on the aftermath of the Fukushima Daiichi nuclear power plant disaster from newspapers and websites. Then I categorized them into four groups, to analyze what the media in the above four counties have reported about Fukushima: 'same context' (typical context), 'a different context from other countries' media', 'a changing context from before', and 'proposals for the decommissioning and reconstruction process in Japan'. (author)

The Human Aspect of the Fukushima Daiichi Accident

International Nuclear Information System (INIS)

Anegawa, T.; Kawano, A.

2016-01-01

Recognizing itself as the main party involved in the nuclear accident triggered by the Tohoku-Chihou-Taiheiyo-Oki Earthquake on March 11, 2011, Tokyo Electric Power Company (TEPCO) has performed accident investigation from various aspects. Results of the investigation are reported mainly in two reports; (1) Fukushima Nuclear Accident Analysis Report (June 20, 2012), which identified the timeline and the proximate causes of the accident, and (2) Summary of Fukushima Nuclear Accident and Nuclear Safety Reform Plan (March 29, 2013) to set forth the results of the investigation and provide an analysis of the background factors surrounding the accident and countermeasures taken. This presentation will first provide overview of the accident response at Fukushima Daiichi and Daini Nuclear Power Stations. Voices from the first responders at the sites will be introduced in order to share thoughts of individuals involved in the emergency response. Summary of retrospective study of the accident by one of the shift supervisors at the time of the accident will be presented in order to share the facts that happened at main control rooms. The shift supervisor and his crew had to manage the situation for extended period of time that exceeded the scenarios that they had been trained, in a situation with no lightning and high radiation condition. During the accident response, shift supervisors had to decide to dispatch some of his crew members to the field to open valves, check the status of equipment etc., in the situation where the high radiation exposure is foreseen. The presentation will include conflict of shift supervisors and crew focusing on the human aspects. In addition, actions being taken at the Emergency Response Centers (ERC) set up at the seismic-isolated building on-site and the Headquarters in Tokyo will be shared focusing on the human aspects related to the accident progress. This includes difficult decisions to dispatch first responders to the field, in the

Study on public awareness of utilizing nuclear power in China. Changes in public awareness after the accident of Fukushima Daiichi Nuclear Power Plants

International Nuclear Information System (INIS)

Xu, Ting; Wakabayashi, Toshio

2012-01-01

The purpose of this study is to clarify public awareness of utilizing nuclear power in China and to determine the effects of the accident of Fukushima Daiichi nuclear power plants. Web online surveys were carried out before and after the accident of Fukushima Daiichi nuclear power plants. The online survey before the accident of Fukushima Daiichi nuclear power plants had 4,255 adult respondents consisting of 1,851 males and 2,404 females. The online survey after the accident had 721 respondents consisting of 406 males and 315 females. The two online surveys about the attitude toward nuclear power plants consisted of 37 items, such as the necessity of nuclear power plants, the reliability of safety, and government confidence. As a result, respondents of the online surveys in China consider that nuclear energy is more important than the anxiety of accident. On the other hand, women have sensation of fear for the accident of Fukushima Daiichi nuclear power plants and radiation. (author)

Fukushima Daiichi: implications for carbon-free energy, nuclear nonproliferation, and community resilience.

Science.gov (United States)

Hall, Howard L

2011-07-01

Implications of the nuclear power plant accidents at Fukushima Daiichi are explored in this commentary. In addition to questions of nuclear reactor regulatory standards, broader implications on noncarbon-emitting energy production, nuclear nonproliferation objectives, and community resilience and emergency response against catastrophic events are explored. Copyright © 2011 SETAC.

Analysis of Fukushima Daiichi Nuclear Power Station severe accident using MAAP4.05

International Nuclear Information System (INIS)

Yoo, Jae S.; Suh, Kune Y.; Kim, Dong M.

2011-01-01

Rather extensive reactor core meltdown and partial melt-through that took place at the Fukushima Daiichi nuclear power plants (NPPs) on March 11, 2011 had been caused by a massive earthquake followed by tsunami rarely seen in history. The happening had turned into an unprecedented serious accident since the Chernobyl Unit 4 in 1986 that extended over multiple reactors simultaneously. A previous documentary survey, NUREG-1150 report provides significant insights into how a severe accident might develop at a boiling water reactor (BWR) and the range of consequences. NUREG-1150 did identify the importance of loss of power accidents for a BWR. This paper describes recent analyses of the Fukushima Daiichi NPPs severe accident. Calculations were performed with the MAAP4.05 code by modifying the parameter file for the Peach Bottom Unit 2, a BWR 4 type in the Mark-I containment. Generally this is the same type of reactor as Fukushima Daiichi Units 2 and 3. This resulted in good understanding of the response of this type of early BWRs to prolonged loss of diesel generators and batteries. There is clearly vulnerability with this early type of BWRs which would be less onerous than later existing plant and new build designs. This analysis, however, was based on rather limited amount of information obtained at the time of preparing this report and adopted various estimates and assumptions for conditions necessary to run the analysis. Hence there persists considerable uncertainty in the results. MAAP4.05 was run pursuant to the observed data and chronology of Fukushima Daiichi Units 1 through 3 reported by the Tokyo Electric Power Company (TEPCO) as well as the Japanese Government. Severe accident scenarios have not only gone far beyond the design basis, but also exceeded the extent of multiple breakdowns assumed in the preparation for such accident management measures as the malfunction or loss of all the emergency core cooling system (ECCS) combined with the extended loss of

Nuclear accidents at the Fukushima Dai-ichi power plant. History, events and consequences

International Nuclear Information System (INIS)

Berniolles, Jean Marc

2011-01-01

Written few weeks after the accident, this article first recalls the circumstances (earthquake and tsunami), and then describes the accidental process within the primary vessels of the Fukushima Dai-ichi number 1, 2 and 3 reactors. The author then describes the interventions which aimed at cooling these three reactors, the problem faced for the storage of used fuels, and then the sequence of accidents: loss of cooling means leading to an explosion, problems faced in the different storage pools. He describes the various steps of recovery (primary cooling, electricity supply), discusses the consequences in terms of radioactivity releases in the plant environment with a comparison with Chernobyl, and also in terms of nature and quantity of radioactive elements. He comments radioactivity controls and measurements, evacuation measures, measurements performed by the IAEA, measurements of sea radioactivity, and the establishment of maps of ground radioactivity around the plant. He discusses the perspectives associated with these measurements for the surroundings of the Fukushima site

Measurement of Iodine-129 in surface soil collected near the Fukushima Daiichi nuclear power plant accident site

International Nuclear Information System (INIS)

Miyake, Yasuto; Matsuzaki, Hiroyuki; Fujiwara, Takeshi; Saito, Takumi; Yamagata, Takeyasu; Honda, Maki

2013-01-01

Iodine-129 in soil around Fukushima Daiichi nuclear power plant were measured by Accelerator Mass Spectrometry and isotopic ratio of radioiodine was estimated. Surface deposition amount of Iodine-129 resulted in 6.7 to 5500 mBq/m"2. The mean isotopic ratio between Iodine-129 and Iodine-131 at the accident was estimated that "1"2"9"I"/"1"3"1I = 26±6 as of March 11 2011. This result was compared to the calculation result of ORIGEN2 code to test the validity of this estimation. (author)

Thermal stratification in a scaled-down suppression pool of the Fukushima Daiichi nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Jo, Byeongnam, E-mail: jo@vis.t.u-tokyo.ac.jp [Nuclear Professional School, The University of Tokyo, 2-22 Shirakata, Tokai-mura, Ibaraki 319-1188 (Japan); Erkan, Nejdet [Nuclear Professional School, The University of Tokyo, 2-22 Shirakata, Tokai-mura, Ibaraki 319-1188 (Japan); Takahashi, Shinji [Department of Nuclear Engineering and Management, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Song, Daehun [Nuclear Professional School, The University of Tokyo, 2-22 Shirakata, Tokai-mura, Ibaraki 319-1188 (Japan); Hyundai and Kia Corporate R& D Division, Hyundai Motors, 772-1, Jangduk-dong, Hwaseong-Si, Gyeonggi-Do 445-706 (Korea, Republic of); Sagawa, Wataru; Okamoto, Koji [Nuclear Professional School, The University of Tokyo, 2-22 Shirakata, Tokai-mura, Ibaraki 319-1188 (Japan)

2016-08-15

Highlights: • Thermal stratification was reproduced in a scaled-down suppression pool of the Fukushima Daiichi nuclear power plants. • Horizontal temperature profiles were uniform in the toroidal suppression pool. • Subcooling-steam flow rate map of thermal stratification was obtained. • Steam bubble-induced flow model in suppression pool was suggested. • Bubble frequency strongly depends on the steam flow rate. - Abstract: Thermal stratification in the suppression pool of the Fukushima Daiichi nuclear power plants was experimentally investigated in sub-atmospheric pressure conditions using a 1/20 scale torus shaped setup. The thermal stratification was reproduced in the scaled-down suppression pool and the effect of the steam flow rate on different thermal stratification behaviors was examined for a wide range of steam flow rates. A sparger-type steam injection pipe that emulated Fukushima Daiichi Unit 3 (F1U3) was used. The steam was injected horizontally through 132 holes. The development (formation and disappearance) of thermal stratification was significantly affected by the steam flow rate. Interestingly, the thermal stratification in the suppression pool vanished when subcooling became lower than approximately 5 °C. This occurred because steam bubbles are not well condensed at low subcooling temperatures; therefore, those bubbles generate significant upward momentum, leading to mixing of the water in the suppression pool.

The Fukushima Daiichi Accident. Technical Volume 4/5. Radiological Consequences. Annexes

International Nuclear Information System (INIS)

2015-08-01

The Fukushima Daiichi Accident consists of a Report by the IAEA Director General and five technical volumes. It is the result of an extensive international collaborative effort involving five working groups with about 180 experts from 42 Member States with and without nuclear power programmes and several international bodies. It provides a description of the accident and its causes, evolution and consequences, based on the evaluation of data and information from a large number of sources available at the time of writing. The Fukushima Daiichi Accident will be of use to national authorities, international organizations, nuclear regulatory bodies, nuclear power plant operating organizations, designers of nuclear facilities and other experts in matters relating to nuclear power, as well as the wider public. The set contains six printed parts and five supplementary CD-ROMs. Contents: Report by the Director General; Technical Volume 1/5, Description and Context of the Accident; Technical Volume 2/5, Safety Assessment; Technical Volume 3/5, Emergency Preparedness and Response; Technical Volume 4/5, Radiological Consequences; Technical Volume 5/5, Post-accident Recovery; Annexes. The Report by the Director General is available separately in Arabic, Chinese, English, French, Russian, Spanish and Japanese

What happened at Fukushima Daiichi Nuclear Power Plants. Verification of effects of earthquake and resulting tsunami

International Nuclear Information System (INIS)

Yamazaki, Tatsuhiro

2012-01-01

At 14:46 on March 11, 2011, the Tohoku District-off the Pacific Ocean Earthquake occurred. The magnitude of this earthquake was 9.0, the largest in Japan's recorded history, and afterwards enormous tsunami struck the Pacific coast of Tohoku District. This great earthquake and resulting tsunami struck the Fukushima Daiichi Nuclear Power Plants (NPPs) of Tokyo Electric Power Co. (TEPCO), whose cooling function was lost and suffered a severe nuclear accident. This article described the mechanism and safety measure of BWR type NPPs and verified how the great earthquake and resulting tsunami affected NPPs. Progression of the accident at Fukushima Daiichi NPPs was outlined. Damage by the earthquake could not be fully inspected but might not be significant to safety systems. However, the earthquake of longer duration time as much as about 250 sec caused failure of breaker or lightening arrester and also damage on electric facility such as transmission line insulator. Tsunami or inundation height was as high as O.P. (Onahama Pile) +11.5-15.5 m for Unit 1-4 reactor area while designed as O.P. +5.7 m, which caused blackout (power outage) and a reactor core meltdown at Fukushima Daiichi NPPs. (T. Tanaka)

MDEP Design-Specific Common Position CP-ABWRWG-01. Common position addressing issues related to the Fukushima Daiichi nuclear power plant accident

International Nuclear Information System (INIS)

2016-01-01

On 11 March 2011 Japan suffered its worst recorded earthquake. The epicentre was 110 miles (180 km) east north east from TEPCO's Fukushima Daiichi NPP which had 6 operating Boiling Water Reactors (BWR). Reactor Units 1, 2 and 3 on this site were operating at power before the event and on detection of the earthquake shut down safely. Reactor Unit 4 was not loaded with any fuel assemblies due to maintenance, including replacement of the core shroud. Reactor Units 5 and 6 were shut down for maintenance. Initially, on-site back-up diesel generators were used to provide the alternating current (AC) electrical supplies to power essential post-trip cooling systems. Within an hour a massive tsunami from the earthquake inundated the site; all AC electrical power to the cooling systems for the reactor and reactor fuel pools was lost, including that from all but one (in Unit 6) back-up diesel generators, as well as a significant amount of direct current (DC) supplies and essential instrumentation. Over the next few hours, and days, the fuel in Reactor Units 1, 2 and 3 heated up and degraded. There were hydrogen explosions which caused considerable damage to the reactor buildings in Units 1, 3 and 4. For over a week the site struggled to put cooling water into the reactors and the reactor fuel pools, by using means untried before and/or unplanned. Electrical supplies were gradually reconnected to the reactor buildings and a degree of control returned. Heavily contaminated water, used to cool the reactors and spent fuel pools, collected in un-contained areas of the site and leaked out to sea. There were also significant releases of radioactivity to the air. However, to date, the indications are that the public health effects from radiation exposure are not significant. This was a serious nuclear accident, with an International Nuclear and Radiological Event Scale (INES) rating of Level 7 (the highest level). Tens of thousands of people were evacuated from a zone extending

AESJ 5 years activities and issues to be solved for the TEPCO's Fukushima Daiichi accident

International Nuclear Information System (INIS)

Uetsuka, Hiroshi; Yamamoto, Akio; Saso, Michitaka

2016-01-01

This paper summarizes the measures taken by the Atomic Energy Society of Japan (AESJ) against the Fukushima Daiichi Accident, and its challenges to the task to be addressed in the future. As recommendations by AESJ, the following five items were pointed out in its final report on the survey on the accident: (1) basic matters on nuclear safety, (2) matters on direct causes of accident, (3) organizational matters among background factors, (4) collective matters, and (5) future matters related to environmental remediation. As the commitment to the Fukushima reconstruction, AESJ performed the introduction of decontamination technologies, hosting of interactive forum and symposium session in Fukushima Prefecture, decontamination test of paddy fields, and preparation of an air dose rate map in Fukushima Prefecture. As for the decommissioning of the Fukushima Daiichi Nuclear Power Station, AESJ prepared guidelines by applying probabilistic risk assessment (PRA) to tsunami, and revised seismic PRA standards. Since there was a lack in the implementation of multiple protections as one of the background causes of the Fukushima Accident, it summarized 'concept of the implementation of multiple protections.' In addition, it surveyed and examined the accident from the viewpoint of human factors, discussed the importance of accident investigation from the viewpoint of a party in charge, and issued a report. (A.O.)

Fukushima - calculation of the reactor core inventory and storage pools Dai-ichi 1 to Dai-ichi 4, an estimation of a source term

International Nuclear Information System (INIS)

Krpelanova, M.; Carny, P.

2011-01-01

Inventory of the reactor core and spent fuel storage pool of the reactors at Dai-ichi 1 to Dai-ichi 4 was determined to need a realistic estimate of the source (released into the atmosphere environment) and modelling of radiological impact of the events in Fukushima NPP. Calculations of inventories were carried out by the methodology that is used in systems to support emergency response and crisis management anymore. Calculations were made based on a model that respects knowledge of real fuels and fuel cycles for individual reactors Dai-ichi. Necessary input data for training the model and calculate inventories are obtained from the IAEA PRIS database.

Partisan amplification of risk: American perceptions of nuclear energy risk in the wake of the Fukushima Daiichi disaster

International Nuclear Information System (INIS)

Yeo, Sara K.; Cacciatore, Michael A.; Brossard, Dominique; Scheufele, Dietram A.; Runge, Kristin; Su, Leona Y.; Kim, Jiyoun; Xenos, Michael; Corley, Elizabeth A.

2014-01-01

Aim: This study examines risk perceptions toward nuclear power before and after the Fukushima Daiichi disaster using nationally representative survey samples of American adults. Scope: On March 11, 2011, a magnitude 8.4 earthquake, the largest in the nation's history, occurred off the coast of Japan. The earthquake produced a devastating tsunami that flooded areas of the Fukushima Daiichi nuclear plant and resulted in a loss of power to the plant's cooling system. In the weeks that followed, the world watched as Japanese and international nuclear power safety experts scrambled to contain the damage and prevent a full meltdown. Although the Fukushima Daiichi disaster was heavily covered in media, there is little empirical research on how this coverage impacted audience risk perceptions. Our analysis goes beyond examining aggregate risk perceptions, instead focusing on how specific sub-populations responded to the disaster. Conclusion: We found that ideological groups responded differently to the events in Japan. In particular, risk perceptions among conservatives decreased following the incident. Moreover, we found that media use exacerbated these effects. We discuss possible explanations for these findings. - Highlights: • We explored American risk perceptions of nuclear energy pre- and post-Fukushima. • Impacts of the disaster endured, likely due to relatively high media coverage. • Conservatives who paid more attention to media perceived less risk post-Fukushima. • Media coverage can serve to polarize opinions instead of mainstreaming them

The Fukushima Daiichi nuclear site. Airborne releases during works on unit 3 in August 2013

International Nuclear Information System (INIS)

2014-07-01

After having briefly recalled the consequences of the earthquake and tsunami on the Fukushima-Daiichi nuclear power station, this document briefly describes what happened to the building of the reactor number 3, and works to be done to dismantle this installation: removal of damaged structures, of debris in the pool, and then removal of fuel from this pool, removal of the core degraded fuel. The removal of structures and debris has been achieved in October 2013, but leaded to radioactive airborne releases. Simulations of atmospheric dispersion have been performed by the IRSN. Radioactive measurements have been also performed, and the evolution of crop contamination between 2011 and 2013 is discussed, notably in the case of rice. Lessons learned can be useful for the dismantling of other units

Implementation of Defence in Depth at Nuclear Power Plants. Lessons Learnt from the Fukushima Daiichi Accident

International Nuclear Information System (INIS)

Lachaume, Jean-Luc; Miller, Douglass; Rzentkowski, Greg; Lahtinen, Nina; Valtonen, Keijo; Foucher, Laurent; Harikumar, Shri S.; Yamada, Tomoho; Sharafutdinov, Rashet; Kuznetsov, Mark; Carlsson, Lennart; Hanberg, Jan; Theiss, Klaus; Holahan, Gary; Williams, Donna; Nuenighoff, Kay; Wattelle, Emmanuel; Lazo, Edward; White, Andrew; Reig, Javier; Salgado, Nancy; Weightman, Mike

2016-01-01

particular attention that human and organisational factors demand; - the concept of 'practical elimination' of sequences leading to significant radioactive releases; - the implementation of DiD for new and existing reactors, multi-unit sites and other nuclear facilities; - the implementation of DiD through regulatory activities (based on a survey among CNRA members); - the protection measures in the DiD concept of level 5 - off-site emergency arrangements. The use of the DiD concept remains valid after the Fukushima Daiichi accident. Indeed, lessons learnt from the accident and its impact on the use of DiD has reinforced its fundamental importance in ensuring adequate safety. This is illustrated by the recent Vienna Declaration on Nuclear Safety adopted by the contracting parties of the Convention on Nuclear Safety. This regulatory guidance booklet also identifies areas where further work may be beneficial, including: - the impact of human and organisational factors on DiD; - improvements on the use of the DiD concept for new reactor designs, multi-unit sites, fuel cycle facilities and research reactors; - the implementation of countermeasures for level 5 of DiD; - benchmarking and further harmonisation of regulatory use of DiD through training, workshops and other means; - the impact of new technologies. (authors)

IAEA report on the Fukushima-Daiichi accident and safety standards

International Nuclear Information System (INIS)

Mizumachi, Wataru

2011-01-01

On March 11th, 2011, 4th largest earthquake attacked Fukushima Nuclear Power Plant and around one hour later, the enormous Tsunami attacked it also. After the large earthquake attacked, the automatic shutdown was performed and the emergency diesel generators automatically started and Isolation condenser cooled down the core for unit 1 and RCIC cooled down the cores for unit 2 and 3. However, the large Tsunami damaged all emergency diesel generators and all ECCS pumps. The core melted and the hydrogen gas were generated by the steam and the zircaloy reaction. The hydrogen leaked into the reactor building and then the reactor building blasted by the hydrogen. IAEA has organized the Great East Japan Earthquake Expert Mission on Fukushima-daiichi accident and they reported to the formal meeting in the headquater in Viena. They made 15 conclusions and 16 lessons and learned. IAEA chairman officially summarized 28 recommendations from them. USNRC published 'Recommendations for Enhanuing Reactor Safety in the 21st Century 'where they summarized 12 Recommendations on Fukushima Accident. Here is the summary of these recommendations. (author)

Morphological abnormalities in gall-forming aphids in a radiation-contaminated area near Fukushima Daiichi: selective impact of fallout?

Science.gov (United States)

Akimoto, Shin-ichi

2014-01-01

To evaluate the impact of fallout from the Fukushima Daiichi Nuclear Power Plant accident on organisms, this study compared the morphology and viability of gall-forming aphids between the Fukushima population and control populations from noncontaminated areas. This study, in particular, focused on the morphology of first-instar gall formers derived from the first sexual reproduction after the accident. Of 164 first instars from Tetraneura sorini galls collected 32 km from Fukushima Daiichi in spring 2012, 13.2% exhibited morphological abnormalities, including four conspicuously malformed individuals (2.4%). In contrast, in seven control areas, first instars with abnormal morphology accounted for 0.0–5.1% (on average, 3.8%). The proportions of abnormalities and mortality were significantly higher in Fukushima than in the control areas. Similarly, of 134 first instars from T. nigriabdominalis galls, 5.9% exhibited morphological abnormalities, with one highly malformed individual. However, of 543 second-generation larvae produced in T. sorini galls, only 0.37% had abnormalities, suggesting that abnormalities found in the first generation were not inherited by the next generation. Although investigation is limited to one study site, this result suggests that radioactive contamination had deleterious effects on embryogenesis in eggs deposited on the bark surface, but a negligible influence on the second generation produced in closed galls. Furthermore, analysis of both species samples collected in spring 2013 indicated that the viability and healthiness of the aphids were significantly improved compared to those in the 2012 samples. Thus, the results of this study suggest the possibility that a reduced level of radiation and/or selection for radiation tolerance may have led to the improved viability and healthiness of the Fukushima population. PMID:24634721

Teaching of severe accident of Fukushima Daiichi Nuclear Power Plants of Tokyo Electric Power

International Nuclear Information System (INIS)

Saito, Shinzo

2011-01-01

The Great East Japan Earthquake and accompanied tsunami brought about the severe accident at Fukushima Daiichi Nuclear Power Plants of Tokyo Electric Power Co., Inc. For 'No more Fukushima', twelve teaching of the accident was pointed out as follows: 1) natural disasters and external events shall be taken into consideration, 2) severe accident shall be included into safety regulation, 3) all possibility of hydrogen explosion shall be excluded, 4) diversity of safety important component and equipment shall be added with sufficient period of outage, 5) siting of multiple units at the same site shall be avoided at quake-prone country like Japan, 6) accident response environment for operators shall be improved, 7) accident convergence termination system shall be established so as to concentrate technical experience and knowledge, 8) off-site center shall be improved, 9) resident evacuation, consumption limit of food, radiation exposure and soil contamination limit shall be decided openly, 10) nuclear regulation and prevention of disaster shall be conducted by unitary organization to gain public trust, 11) fostering of safety culture among relevant enterprises shall be more encouraged and 12) nuclear industry shall develop reactor such as with no core meltdown or no evacuation and environmental contamination even if reactor core would be meltdown. (T. Tanaka)

Evacuation after the Fukushima Daiichi Nuclear Power Plant Accident Is a Cause of Diabetes: Results from the Fukushima Health Management Survey

Directory of Open Access Journals (Sweden)

Hiroaki Satoh

2015-01-01

Full Text Available The Great East Japan Earthquake and Fukushima Daiichi nuclear disaster in 2011 forced the evacuation of a large number of residents and created changes in the lifestyle of the evacuees. These changes may have affected the evacuees’ glucose metabolism, thereby leading to an increase in the incidence of diabetes. This study included Japanese men and women who were living near the Fukushima Daiichi Nuclear Power Plant in Fukushima prefecture before the disaster. Subjects subsequently underwent annual health checkups with a focus on metabolic syndromes, which were conducted under the Health Care Insurers. Using the Comprehensive Health Check survey, we analyzed changes in the glucose metabolism before and after the disaster. A total of 27,486 subjects underwent follow-up examinations after the disaster, with a mean follow-up period of 1.6 years. After the disaster, the prevalence of diabetes increased significantly, and we observed that the incidence of diabetes was significantly greater among evacuees than among nonevacuees. Furthermore, multivariate logistic regression analysis revealed that evacuation was significantly associated with the incidence of diabetes. In conclusion, this is the first study to demonstrate that evacuation is associated with the incidence of diabetes. This information may be used to guide follow-up recommendations for evacuees.

The effects of the nuclear disaster at Fukushima Daiichi Nuclear Power Station on local governments

International Nuclear Information System (INIS)

Nakamura, Makoto; Dake, Kinji

2012-01-01

All Japan council of local governments with atomic power stations consisted of 24 reactor site and 6 neighboring local governments to solve reactor site related problems. Nuclear disaster at Fukushima Daiichi Nuclear Power Station affected member local governments to be forced in severe conditions such as 'removal of administrative function' or 'refuge over a wide district beyond local government area', not imagined before. The council set up working group for thirteen local governments themselves to investigate this disaster and find safety and prevention of disaster measures to be deployed in nuclear administration, which published report in March 2012. This article described outline of investigation and derived problems and direction of their solution. Main items were related with communication, resident evacuation, prevention of disaster system, and management of refuge site. (T. Tanaka)

Monitoring Cs-134 and 137 released by Fukushima Dai-ichi Nuclear Power Plant accident in ground, soil, and stream waters

Science.gov (United States)

Tsujimura, Maki; Onda, Yuichi; Hada, Manami; Ishwar, Pun; Abe, Yutaka

2013-04-01

Due to Fukushima Dai-ichi Nuclear power plant accident occurred in March 2011, large amount of radionuclides was released into the atmosphere and was fallen onto ground by rainfall. Few researches have monitored radioactive cesium dynamics in whole hydrological cycle system such as groundwater, soil water, spring water and stream water. Thus, the purpose of this study is to monitor concentration of radioactive cesium in those waters in time series in the headwaters. We have performed an intensive monitoring at three small mountainous catchments in Yamakiya district, Kawamata town, Fukushima prefecture, locating 35 km northwest from Fukushima Dai-ichi Nuclear Power Plant since June 2011, also we consider the movement of radioactive cesium and its relation with the hydrological cycle.

A concept of countermeasure against radioactive wastewater generated in disastrous nuclear accident such as Fukushima Daiichi site case

Energy Technology Data Exchange (ETDEWEB)

Kim, Kwang-Wook; Lee, Keun-Young; Lee, Eil-Hee; Baek, Yeji; So, Ji-Yang; Chung, Dong-Young; Moon, Jei-Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-10-15

Before the operation of initial wastewater treatment systems supplied by AREVA and Kurion companies, which were installed about 6 months after the accident, the contaminated water was accumulated in reactor and turbine buildings, then was moved and stored in many hurriedly-prepared storage tanks including even mega float barge. The wastewater treatment systems using Cs-adsorption columns and desalination equipment was not properly operated and there were several small and big leakages of contaminated water from the wastewater treatment system and storage tanks, so that tremendous wastewater had been accumulated during those periods. That thereafter led to many secondary problems in management and treatment of the wastewater. Since the disastrous accident at Fukushima, several measures to more enhance safety of nuclear power plants located on coastal area have been asked. As one of them, a countermeasure against generation of tremendous radioactive wastewater in disastrous nuclear accident like the Fukushima Daiichi station was asked to be prepared.

Corium Configuration and Penetration Tube Failure for Fukushima Daiichi Nuclear Power Plant

International Nuclear Information System (INIS)

An, Sang Mo; Lee, Jae Bong; Kim, Hwan Yeol; Song, Jin Ho

2016-01-01

For the LWRs (light water reactors), the penetration tubes at the reactor vessel lower head are regarded as the most vulnerable structures along with a global vessel failure during a severe accident because they can be seriously damaged by a corium melt or debris relocated into the lower plenum of the vessel. The research on the penetration tube failure is of higher importance in the BWRs, as it could lead to melt discharge into the containment and subsequent release of radioactive materials to the environment due to the containment failure. There are more than one hundred of penetration tubes in the Fukushima Daiichi NPPs (nuclear power plants), such as ICM-GTs (in-core monitoring guide tubes), CRGTs (control rod guide tubes) and drain tubes. The ICM-GTs include SRMs (source range monitors), IRMs (intermediate range monitors), LPRMs (local power range monitors) and TIPs (traversing in-core probes), which are much thinner than other tubes. The experimental researches to investigate the corium configuration and the penetration tube failure for the Fukushima Daiichi NPPs were introduced and some meaningful results were summarized. It was shown that the corium ingot was separated into two layers, of which the upper layer was metal-rich while the lower one was oxide-rich. It seemed that B 4 C would contribute to reducing the density of the metallic melt. The two-layered configuration will provide useful information to understand the core melt progression and post-recovery actions for the Fukushima Daiichi NPPs. In addition, we performed a large scale penetration tube failure experiment for the SRM/IRM guide tube, and showed high possibilities of large amount of corium discharge out of the reactor vessel lower head, which followed by the tube melting in a very short time. We are planning to perform the penetration tube failure experiments for another dry tube of ICM-GT (LPRM guide tube), and later for the wet tube (CRGT)

Corium Configuration and Penetration Tube Failure for Fukushima Daiichi Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

An, Sang Mo; Lee, Jae Bong; Kim, Hwan Yeol; Song, Jin Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

For the LWRs (light water reactors), the penetration tubes at the reactor vessel lower head are regarded as the most vulnerable structures along with a global vessel failure during a severe accident because they can be seriously damaged by a corium melt or debris relocated into the lower plenum of the vessel. The research on the penetration tube failure is of higher importance in the BWRs, as it could lead to melt discharge into the containment and subsequent release of radioactive materials to the environment due to the containment failure. There are more than one hundred of penetration tubes in the Fukushima Daiichi NPPs (nuclear power plants), such as ICM-GTs (in-core monitoring guide tubes), CRGTs (control rod guide tubes) and drain tubes. The ICM-GTs include SRMs (source range monitors), IRMs (intermediate range monitors), LPRMs (local power range monitors) and TIPs (traversing in-core probes), which are much thinner than other tubes. The experimental researches to investigate the corium configuration and the penetration tube failure for the Fukushima Daiichi NPPs were introduced and some meaningful results were summarized. It was shown that the corium ingot was separated into two layers, of which the upper layer was metal-rich while the lower one was oxide-rich. It seemed that B{sub 4}C would contribute to reducing the density of the metallic melt. The two-layered configuration will provide useful information to understand the core melt progression and post-recovery actions for the Fukushima Daiichi NPPs. In addition, we performed a large scale penetration tube failure experiment for the SRM/IRM guide tube, and showed high possibilities of large amount of corium discharge out of the reactor vessel lower head, which followed by the tube melting in a very short time. We are planning to perform the penetration tube failure experiments for another dry tube of ICM-GT (LPRM guide tube), and later for the wet tube (CRGT)

Hydrogen combustion in a flat semi-confined layer with respect to the Fukushima Daiichi accident

International Nuclear Information System (INIS)

Kuznetsov, M.; Yanez, J.; Grune, J.; Friedrich, A.; Jordan, T.

2012-01-01

The hydrogen accumulation at the top of containment or reactor building may occur due to an interaction of molten corium and water followed by a severe accident of a nuclear reactor (TMI, Chernobyl, Fukushima Daiichi). The hydrogen, released from the reactor, accumulates usually as a stratified semi-confined layer of hydrogen-air mixture. A series of large scale experiments on hydrogen combustion and explosion in a semi-confined layer of uniform and non-uniform hydrogen-air mixtures in presence of obstructions or without them was performed at the Karlsruhe Inst. of Technology (KIT). Different flame propagation regimes from slow subsonic to relative fast sonic flames and then to the detonations were experimentally investigated in different geometries and then simulated with COMSD code with respect to evaluate amount of burnt hydrogen taken place during the Fukushima Daiichi Accident (FDA). The experiments were performed in a horizontal semi-confined layer with dimensions of 9x3x0.6 m with/without obstacles opened from below. The hydrogen concentration in the mixtures with air was varied in the range of 0-34 vol. % without or with a gradient of 0-60 vol. %H 2 /m. Effects of hydrogen concentration gradient, thickness of the layer, geometry of the obstructions, average and maximum hydrogen concentration on flame propagation regimes were investigated with respect to evaluate the maximum pressure loads of internal structures. Blast wave strength and dynamics of propagation after explosion of the layer of hydrogen-air mixture was numerically simulated to reproduce the hydrogen explosion process during the Fukushima Daiichi Accident. (authors)

Mental health problems after the 2011 Fukushima Dai-ichi nuclear power plant accident

International Nuclear Information System (INIS)

Niwa, Shin-ichi

2012-01-01

The name of Fukushima has now become well-known worldwide after Hiroshima and Nagasaki as the third place exposed to radiation in Japan. This radiation pollution has severely damaged the chief industries of Fukushima Prefecture, namely agriculture, fishery, and tourist industry. It has also stimulated strong anxious feelings among parents with young children. The accident has caused a critical situation in the psychiatric and mental health services in Fukushima as well. Five hospitals with psychiatric beds within 30 km from the Fukushima Dai-ichi Nuclear Power Plant were ordered to transfer their inpatients to other hospitals outside the designated 30 km-areas and to close down the hospitals immediately after the nuclear plant accident. In total, more than 800 psychiatric beds disappeared in an instant, and 1,228 persons including psychiatric inpatients and residents of elderly people nursing homes were transferred to other facilities far away. Rational explanation that low-level radiation in Fukushima will not do harm to people did not necessarily relieve existing anxiety among people. The terms 'safety' and 'relief' are usually used in combination; however, 'relief' was separated from 'safety' this time in Fukushima. People gradually began to feel 'relieved', when they themselves got involved in the cleaning work of radiation although its effect remained ambiguous. Now we have the following mental health problems after the 2011 Fukushima Dai-ichi nuclear power plant accident; recovery and maintenance of treatment systems for psychiatric patients in the affected areas, efforts for early detection and intervention of depression, severe stress disorder, adaptation disorder, and alcohol abuse which are expected to occur due to the earthquake and radiation pollution, prevention of suicides, relief from anxiety resulting from radiation pollution, adequate treatment of mental problems among children with long-term evacuation, prevention of fall in physical and mental

Fukushima Daiichi - delivery of contaminated water into the Pacific ocean and possible consequences for the marine ecosystem

International Nuclear Information System (INIS)

Nies, Hartmut

2015-01-01

The nuclear power plant Fukushima Daiichi is sited at the coast of the Japanese island Honshu. Most of the cooling water for the three destroyed reactors units 1-3 and the nuclear fuel in the spent fuel pool of unit-4 were uncontrolled delivered into the groundwater and the Pacific Ocean. As a consequence high concentrations of I-131, Cs-134 and Cs-137 in the coastal waters have to be assumed. The contribution analyzed the possible consequences for the marine ecosystem. A drift time of 5 to 7 years toward the coast of North America is expected. The planning of the marine monitoring program MEXT is described. Radiation measurements in the coastal water up to 200 km distance from Daiichi were performed. The highest radionuclide concentrations of Cs-137 and Cs-134 were found in the fine grained sediments. No increased radioactivity in seafood is expected.

Spatio-temporal variability of the deposited radioactive materials in forest environments after the Fukushima Daiichi NPP accident

Science.gov (United States)

Kato, H.; Onda, Y.; Komatsu, Y.; Yoda, H.

2012-12-01

Soil, vegetation and other ecological compartments are expected to be highly contaminated by the deposited radionuclides after the Fukushima Daiichi nuclear power plant (NPP) accident triggered by a magnitude 9.1 earthquake and the resulting tsunami on Marchi 11, 2011. Study site have been established in Yamakiya district, Kawamata Town, Fukushima prefecture, located about 35 km from Fukushima power plant, and designated as the evacuated zone. The total deposition of radioactive materials at the study site ranged from 0.02to >10 M Bq/m2 for Cs-137. The mature cedar, young cedar, and broad-leaf stands were selected as experimental site for the monitoring of spatio-temporal variability of the deposited radionuclides after the accidental release of radioactive materials. In order to measure the vertical distribution of radioactivity in forest, a tower with the same height of tree have been established at each experimental site. The measurement of radioactivity by using a portable Ge gamma-ray detector (Detective-DX-100, Ortec) and radionuclide analysis of leaf samples at different height revealed that a large proportion of radionuclides which deposited on forest were trapped by canopies of the cedar forests. In contrast, in the broad-leaf forest highest radioactivity was found at the forest floor. Furthermore, spatio-temporal variability of radioactivity at the forest floor indicated that huge amount of caesium still remains on the canopy of coniferous forest, and subsequently transfers to forest floor in association with throughfall, stemflow, and litter fall.

The Fukushima Daiichi Accident. Technical Volume 3/5. Emergency Preparedness and Response. Annexes

International Nuclear Information System (INIS)

2015-08-01

The Fukushima Daiichi Accident consists of a Report by the IAEA Director General and five technical volumes. It is the result of an extensive international collaborative effort involving five working groups with about 180 experts from 42 Member States with and without nuclear power programmes and several international bodies. It provides a description of the accident and its causes, evolution and consequences, based on the evaluation of data and information from a large number of sources available at the time of writing. The Fukushima Daiichi Accident will be of use to national authorities, international organizations, nuclear regulatory bodies, nuclear power plant operating organizations, designers of nuclear facilities and other experts in matters relating to nuclear power, as well as the wider public. The set contains six printed parts and five supplementary CD-ROMs. Contents: Report by the Director General; Technical Volume 1/5, Description and Context of the Accident; Technical Volume 2/5, Safety Assessment; Technical Volume 3/5, Emergency Preparedness and Response; Technical Volume 4/5, Radiological Consequences; Technical Volume 5/5, Post-accident Recovery; Annexes. The Report by the Director General is available separately in Arabic, Chinese, English, French, Russian, Spanish and Japanese

Restoration of water environment contaminated by radioactive cesium released from Fukushima Daiichi NPP

Energy Technology Data Exchange (ETDEWEB)

Takeshita, K.; Takahashi, H. [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 157-8550 (Japan); Jinbo, Y. [CDM Cosulting Co.Ltd., 1-13-13 Tsukiji Chuo-ku Tokyo 104-0045 (Japan); Ishido, A. [Radwaste and Decommissioning Center, 1-7-6 Toranomon, Minato-ku, Tokyo 105-0001 (Japan)

2013-07-01

In the Fukushima Daiichi NPP Accident, large amounts of volatile radioactive nuclides, such as {sup 131}I, {sup 134}Cs and {sup 137}Cs, were released to the atmosphere and huge areas surrounding the nuclear site were contaminated by the radioactive fallout. In this study, a combined process with a hydrothermal process and a coagulation settling process was proposed for the separation of radioactive Cs from contaminated soil and sewage sludge. The coagulation settling operation uses Prussian Blue (Ferric ferrocyanide) and an inorganic coagulant. The recovery of Cs from sewage sludge sampled at Fukushima city (100.000 Bq/kg) and soil at a nearby village (55.000 Bq/kg), was tested. About 96% of Cs in the sewage sludge was removed successfully by combining simple hydrothermal decomposition and coagulation settling. However, Cs in the soil was not removed sufficiently by the combined process (Cs removal is only 56%). The hydrothermal decomposition with blasting was carried out. The Cs removal from the soil was increased to 85%. When these operations were repeated twice, the Cs recovery was over 90%. The combined process with hydrothermal blasting and coagulation settling is applicable to the removal of Cs from highly contaminated soil.

Hydrogen combustion in a flat semi-confined layer with respect to the Fukushima Daiichi accident

Energy Technology Data Exchange (ETDEWEB)

Kuznetsov, Mike, E-mail: kuznetsov@kit.edu [Karlsruhe Institute of Technology, 76131 Karlsruhe (Germany); Yanez, Jorge [Karlsruhe Institute of Technology, 76131 Karlsruhe (Germany); Grune, Joachim; Friedrich, Andreas [Pro-Science GmbH, 76275 Ettlingen (Germany); Jordan, Thomas [Karlsruhe Institute of Technology, 76131 Karlsruhe (Germany)

2015-05-15

Graphical abstract: - Highlights: • Critical conditions for flame propagation regimes in a layer geometry are analyzed. • Numerical simulation of hydrogen explosion reproduces real strength of shock waves. • From 80 to 200 kg of hydrogen were exploded during Fukushima (Unit I) accident. • A sonic deflagration with TNT equivalent of 800 kg was the most probable regime. - Abstract: Hydrogen accumulations at the top of a containment or reactor building may occur due to the interaction of molten corium and water followed by a severe accident of a nuclear reactor (TMI, Chernobyl, Fukushima Daiichi). The hydrogen that is released from the reactor accumulates usually as a stratified semi-confined layer of hydrogen–air mixture. A series of large scale experiments on hydrogen combustion and explosion in a semi-confined layer of uniform and non-uniform hydrogen–air mixtures in the presence of obstructions or without them was performed at the Karlsruhe Institute of Technology (KIT). Different flame propagation regimes from slow subsonic to relatively fast sonic flames and then to detonations were experimentally investigated in different geometries and then simulated with COM3D code with respect to evaluate the amount of hydrogen that was involved in the Fukushima Daiichi Accident (FDA). The experiments were performed in a horizontal semi-confined layer with the dimensions 9 × 3 × 0.6 m with/without obstacles opened from below. The hydrogen concentration in the mixtures with air was varied in the range of 10–34 vol.% without or with a gradient of 20–60 vol.%H{sub 2}/m. Effects of hydrogen concentration gradient, layer thickness, obstruction geometry, average and maximum hydrogen concentration on the flame propagation regimes were investigated with respect to evaluate the maximum pressure loads on internal structures. Blast wave strength and dynamics of propagation after the explosion of the hydrogen–air mixture layer were numerically simulated to reproduce

Development of prediction models for radioactive caesium distribution within the 80-km radius of the Fukushima Daiichi nuclear power plant

International Nuclear Information System (INIS)

Kinase, Sakae; Sato, Satoshi; Saito, Kimiaki; Takahashi, Tomoyuki; Sakamoto, Ryuichi

2014-01-01

Preliminary prediction models have been studied for the radioactive caesium distribution within the 80-km radius of the Fukushima Daiichi nuclear power plant. The models were represented by exponential functions using ecological half-life of radioactive caesium in the environment. The ecological half-lives were derived from the changes in ambient dose equivalent rates through vehicle-borne surveys. It was found that the ecological half-lives of radioactive caesium were not constant within the 80-km radius of the Fukushima Daiichi nuclear power plant. The ecological half-life of radioactive caesium in forest areas was found to be much larger than that in urban and water areas. (authors)

Risk Analysis of Fukushima Accident using MACCS2

Energy Technology Data Exchange (ETDEWEB)

Lee, Seunghee; Kim, Juyoul; Kim, Sukhoon; Kim, Juyub [FNC Technology Co. Ltd., Yongin (Korea, Republic of)

2014-05-15

It has been three years since Fukushima Daiichi accident had occurred. Many efforts have been done for a restoration, however, radioactive materials are still released resulting in a crucial additional damage to a human health and economics and the scale of damage is not much evaluated. Therefore, an estimation of damage degree caused by the released radioactive materials right after a nuclear accident is essential to cope with additional radioactive problems. Here, we report the risk analysis of Fukushima Dai-ichi accident using MELCOR Accident Consequence Code System 2 (MACCS2), which is the Nuclear Regulatory Commission's (NRC's) code for evaluating off-site consequences. It is used in level-3 Probabilistic Risk Analyses (PRA), for planning purposes, for cost-benefit analyses and so on. The purpose of this study is to estimate radiological doses and health risks of Fukushima Daiichi accident through short- and long-term of lifetime using MACCS2. In summary, the health risk for inhabitants near Fukushima Daiichi NPP has been evaluated by considering the long term radiation effect using MACCS2 code. The result indicates that the occurrence and death rate of the cancer have been increased by the radioactive materials released from Fukushima Daiichi accident. The result obtained in this study may provide new insights for taking action after the nuclear reactor accident to mitigate the released radioactive materials and to prepare the countermeasure.

MDEP AP1000WG Design-Specific Common Position CP-AP1000WG-02. Common position addressing Fukushima Daiichi NPP accident-related issues

International Nuclear Information System (INIS)

2016-09-01

A severe accident involving several units took place in Japan at Fukushima Daiichi nuclear power plant (NPP) in March 2011. The immediate cause of the accident was an earthquake followed by a tsunami coupled with inadequate provisions against the consequences of such events in the design. Opportunities to improve protection against a realistic design basis tsunami had not been taken. As a consequence of the tsunami, safety equipment and the related safety functions were lost at the plant, leading to core damage in three units and subsequently to large radioactive release. Several studies have already been performed to better understand the accident progression and detailed technical studies are still in progress in Japan and elsewhere. In the meantime, on-going studies on the behaviour of nuclear power plants in very severe situations, similar to Fukushima Daiichi, seek to identify potential vulnerabilities in plant design and operation; to suggest reasonably practicable upgrades; or to recommend enhanced regulatory requirements and guidance to address such situations. Likewise, agencies around the world that are responsible for regulating the design, construction and operation of AP1000 R plants are engaged in similar activities. The MDEP AP1000 R Working Group (AP1000 WG) members consist of members from Canada, China, the United Kingdom and the United States. Since the regulatory review of their AP1000 R applications have not been completed by all of these Countries yet, this paper identifies common preliminary approaches to address potential safety improvements for AP1000 R plants as related to lessons learned from the Fukushima Daiichi accident or Fukushima Daiichi-related issues. In seeking common position, regulators will provide input to this paper to reflect their safety conclusions regarding the AP1000 R design and how the design could be enhanced to address Fukushima Daiichi issues. The common preliminary approaches are organized into five sections

MDEP Common Position CP-STC-02. Common Position Addressing Fukushima Daiichi Nuclear Power Accident

International Nuclear Information System (INIS)

2016-09-01

Following the nuclear accident in Japan as a consequence of the earthquake and tsunami, the MDEP Members provide the following information, based on initial information available, to ensure adequate safety of new reactor design activities being undertaken pursuant to the MDEP program of work. Due to the extensive nature of the magnitude and duration of the Fukushima Daiichi NPP accident, it is important to consider lessons learnt at an early stage of the design. In this context, the extensive work done by the IAEA, the International Atomic Energy Agency, is also acknowledged. Vendors, licensees and applicants involved in New Design activities should examine the implications of the Fukushima Daiichi NPP accident and identify relevant issues to be taken into account to strengthen defense in depth. Those lessons learnt should include, but not be limited to, plans to assess the following: - Provisions taken in the design basis concerning flooding, earthquake, other extreme natural phenomena and combinations of external event hazards appropriate to each country, - The robustness of the plant to maintain its safety functions beyond the design basis hazards, - The capability of the plant to withstand extended loss of all electrical power supplies as well as prolonged loss of ultimate heat sink and other essential supplies, and - The capability of the plant to cope with such extreme situations, including provisions to manage severe accidents (such as combustible gas management). In assessing these areas, the effect of multiple units and nuclear fuel storages should be considered. The MDEP regulators will strive to harmonize approaches to incorporate lessons learnt in their ongoing national safety reviews of new reactors. Based on the design-specific common positions, this paper identifies the approaches to address potential safety improvements for several designs as related to lessons learned from the Fukushima Daiichi NPP accident or related issues. Designs being

Emergency feature. Great east Japan earthquake disaster Fukushima Daiichi accident

International Nuclear Information System (INIS)

Kawata, Tomio; Tsujikura, Yonezo; Kitamura, Toshiro

2011-01-01

The Tohoku Pacific Ocean earthquake occurred in March 11, 2011. The disastrous tsunami attacked Fukushima Daiichi nuclear power plants after automatically shutdown by the earthquake and all motor operated pumps became inoperable due to station black out. Despite the strenuous efforts of operators, if caused serious accident such as loss of cooling function, hydrogen explosion and release of large amount of radioactive materials into the environment, leading to nuclear power emergency that ordered resident to evacuate or remain indoors. This emergency feature consisted of four articles. The first was the interview with the president of JAIF (Japan Atomic Industrial Forum) on how to identify the cause of the accident completely, intensify safety assurance measures and promote discussions on a role of nuclear power in the nation's entire energy policy toward the reconstruction. Others were reactor states and events sequence after the accident with trend data of radiation in the reactor site, statement of president of AESJ (Atomic Energy Society of Japan) on nuclear crisis following Tohoku Pacific Ocean earthquake our response and my experience in evacuation life. (T. Tanaka)

Distribution of dose rates due to fallout from the Fukushima Daiichi reactor accident

International Nuclear Information System (INIS)

Minato, Susumu

2011-01-01

A number of dose rate data taken after the Fukushima Daiichi reactor accident occurred have been collected through official websites of prefectural governments. Subtracting natural background dose rates from these data, contributions due to fallout alone were evaluated. A train-borne survey was carried out to verify the accuracy of the contour map. The dose rate variation pattern obtained by the survey coincided fairly well with that of the map. (author)

Investigation and evaluation for environmental impact at Fukushima Daiichi NPP accident

International Nuclear Information System (INIS)

2012-01-01

In 2012, JNES investigated the weather data and the environmental monitoring data and constructed the method to specify contribution of the environmental impact from each plant based on the dose analysis result at Unit 1-3 of Fukushima Daiichi NPP accident. JNES calculated the dose rate in an accident early stage based on analysis of a monitoring data. Moreover, JNES evaluated the dose by additional release of the radioactive material in case of assuming the loss of coolant injection to a nuclear reactor by the request of NISA. (author)

A Remote-operated System to Map Radiation Dose in the Fukushima Daiichi Primary Containment Vessel

Science.gov (United States)

Nancekievill, M.; Jones, A. R.; Joyce, M. J.; Lennox, B.; Watson, S.; Katakura, J.; Okumura, K.; Kamada, S.; Katoh, M.; Nishimura, K.

2018-01-01

This paper describes the development of a submersible system based on a remote-operated vehicle coupled with radiation detectors to map the interior of the reactors at the Fukushima Daiichi nuclear power station. It has the aim oflocating fuel debris. The AVEXIS submersible vehicle used in this study has been designed as a low-cost, potentially disposable, inspection platform that is the smallest of its class and is capable of being deployed through a 150 mm diameter access pipe. To map the gamma-ray environment, a cerium bromide scintillator detector with a small form factor has been incorporated into the AVEXIS to identify radioactive isotopes via gamma-ray spectroscopy. This provides the combined system with the potential to map gamma-ray spectra and particle locations throughout submerged, contaminated facilities, such as Units 1, 2 and 3 of the Fukushima Daiichi nuclear power plant. The hypothesis of this research is to determine the sensitivity of the combined system in a submerged environment that replicates the combination of gamma radiation and water submersion but at lower dose rates.

Plutonium release from Fukushima Daiichi fosters the need for more detailed investigations

Science.gov (United States)

Schneider, Stephanie; Walther, Clemens; Bister, Stefan; Schauer, Viktoria; Christl, Marcus; Synal, Hans-Arno; Shozugawa, Katsumi; Steinhauser, Georg

2013-10-01

The contamination of Japan after the Fukushima accident has been investigated mainly for volatile fission products, but only sparsely for actinides such as plutonium. Only small releases of actinides were estimated in Fukushima. Plutonium is still omnipresent in the environment from previous atmospheric nuclear weapons tests. We investigated soil and plants sampled at different hot spots in Japan, searching for reactor-borne plutonium using its isotopic ratio 240Pu/239Pu. By using accelerator mass spectrometry, we clearly demonstrated the release of Pu from the Fukushima Daiichi power plant: While most samples contained only the radionuclide signature of fallout plutonium, there is at least one vegetation sample whose isotope ratio (0.381 +/- 0.046) evidences that the Pu originates from a nuclear reactor (239+240Pu activity concentration 0.49 Bq/kg). Plutonium content and isotope ratios differ considerably even for very close sampling locations, e.g. the soil and the plants growing on it. This strong localization indicates a particulate Pu release, which is of high radiological risk if incorporated.

FUKUSHIMA DAI-ICHI ACCIDENT: LESSONS LEARNED AND FUTURE ACTIONS FROM THE RISK PERSPECTIVES

Directory of Open Access Journals (Sweden)

JOON-EON YANG

2014-02-01

Full Text Available The Fukushima Dai-Ichi accident in 2011 has affected various aspects of the nuclear society worldwide. The accident revealed some problems in the conventional approaches used to ensure the safety of nuclear installations. To prevent such disastrous accidents in the future, we have to learn from them and improve the conventional approaches in a more systematic manner. In this paper, we will cover three issues. The first is to identify the key issues that affected the progress of the Fukushima Dai-Ichi accident greatly. We examine the accident from a defense-in-depth point of view to identify such issues. The second is to develop a more systematic approach to enhance the safety of nuclear installations. We reexamine nuclear safety from a risk point of view. We use the concepts of residual and unknown risks in classifying the risk space. All possible accident scenarios types are reviewed to clarify the characteristics of the identified issues. An approach is proposed to improve our conventional approaches used to ensure nuclear safety including the design of safety features and the safety assessments from a risk point of view. Finally, we address some issues to be improved in the conventional risk assessment and management framework and/or practices to enhance nuclear safety.

Fukushima Dai-Ichi accident: Lessons Learned and Future Actions from the Risk Perspectives

Energy Technology Data Exchange (ETDEWEB)

Yang, Jooneon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-02-15

The Fukushima Dai-Ichi accident in 2011 has affected various aspects of the nuclear society worldwide. The accident revealed some problems in the conventional approaches used to ensure the safety of nuclear installations. To prevent such disastrous accidents in the future, we have to learn from them and improve the conventional approaches in a more systematic manner. In this paper, we will cover three issues. The first is to identify the key issues that affected the progress of the Fukushima Dai-Ichi accident greatly. We examine the accident from a defense-in-depth point of view to identify such issues. The second is to develop a more systematic approach to enhance the safety of nuclear installations. We reexamine nuclear safety from a risk point of view. We use the concepts of residual and unknown risks in classifying the risk space. All possible accident scenarios types are reviewed to clarify the characteristics of the identified issues. An approach is proposed to improve our conventional approaches used to ensure nuclear safety including the design of safety features and the safety assessments from a risk point of view. Finally, we address some issues to be improved in the conventional risk assessment and management framework and/or practices to enhance nuclear safety.

Analysis of the accident at Fukushima Daiichi nuclear power plant in an A BWR reactor; Analisis del accidente de la planta nucleoelectrica de Fukushima Daiichi en un reactor tipo ABWR

Energy Technology Data Exchange (ETDEWEB)

Escorcia O, D. [UNAM, Facultad de Ingenieria, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Salazar S, E., E-mail: daniel.escorcia.ortiz@gmail.com [UNAM, Facultad de Ingenieria, Laboratorio de Analisis en Ingenieria de Reactores Nucleares, 62250 Jiutepec, Morelos (Mexico)

2016-09-15

The present work aims to recreate the accident occurred at the Fukushima Daiichi nuclear power plant in Japan on March 11, 2011, making use of an academic simulator of forced circulation of the A BWR reactor provided by the IAEA to know the scope of this simulator. The simulator was developed and distributed by the IAEA for academic purposes and contains the characteristics and general elements of this reactor to be able to simulate transients and failures of different types, allowing also to observe the general behavior of the reactor, as well as several phenomena and present systems in the same. Is an educational tool of great value, but it does not have a scope that allows the training of plant operators. To recreate the conditions of the Fukushima accident in the simulator, we first have to know what events led to this accident, as well as the actions taken by operators and managers to reduce the consequences of this accident; and the sequence of events that occurred during the course of the accident. Differences in the nuclear power plant behavior are observed and interpreted throughout the simulation, since the Fukushima plant technology and the simulator technology are not the same, although they have several elements in common. The Fukushima plant had an event that by far exceeded the design basis, which triggered in an accident that occurred in the first place by a total loss of power supply, followed by the loss of cooling systems, causing a level too high in temperature, melting the core and damaging the containment accordingly, allowing the escape of hydrogen and radioactive material. As a result of the simulation, was determined that the scope of the IAEA academic simulator reaches the entrance of the emergency equipment, so is able to simulate almost all the events occurred at the time of the earthquake and the arrival of the tsunami in the nuclear power plant of Fukushima Daiichi. However, due to its characteristics, is not able to simulate later

Pu distribution in seawater in the near coastal area off Fukushima after the Fukushima Daiichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Bu, W.T.; Zheng, J.; Aono, T.; Wu, J.W.; Tagami, K.; Uchida, S.; Guo, Q.J.; Yamada, M.

2015-01-01

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident released large amount of radionuclides into the marine environment. Compared with the fission products, data on the distributions of Pu in the marine environment of the western North Pacific after the accident is limited. To better understand the Pu contamination in the marine environment after the accident, for the first time, we determined Pu isotope ratio ( 240 Pu/ 239 Pu) in addition to 239+240 Pu activity in seawater collected in the near coastal area (mostly within the 30 km zone) off the FDNPP site. The 239+240P u activities were 4.16-5.52 mBq/m 3 and the 240 Pu/ 239 Pu atom ratios varied from 0.221 to 0.295. These values were compared with the baseline data for Pu distribution in the near coast seawaters before the FDNPP accident (2008-2010). The results suggested that there is no significant Pu contamination in seawater in the near coastal area off the FDNPP site from the accident two years after the accident. (author)

SFR Safety Consideration in Light of Fukushima Dai-ichi Accident

International Nuclear Information System (INIS)

Yamaguchi, Akira

2013-01-01

SFR Considerations: Fukushima Dai-ichi Accident: • Combined LORL and LOHS type initiated from SBO; • High pressure water-steam cooling system: – Depressurization - Not needed; – Ultimate heat sink - Robust (NC to atmosphere); – Continuous injection - Not needed (large sensible heat capacity). • Severe accident management: – RPV failure resulted in depressurization - Elevated temperature; – Heat sink to atmosphere - Freeing risk, sodium fire risk; – Mobile power supply - External resource may not be needed; – Seawater injection with fire engines - Sodium injection not needed; • Containment performance and accessibility: – Containment - Large containment volume and low pressure system; – Explosives - Sodium fire and hydrogen explosion

Atmospheric dispersion modeling: Challenges of the Fukushima Daiichi response

Energy Technology Data Exchange (ETDEWEB)

Sugiyama, Gayle [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nasstrom, John [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Pobanz, Brenda [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Foster, Kevin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Simpson, Matthew [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vogt, Phil [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Aluzzi, Fernando [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Homann, Steve [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2012-05-01

In this research, the U.S. Department of Energy’s (DOE) National Atmospheric Release Advisory Center (NARAC) provided a wide range of predictions and analyses as part of the response to the Fukushima Daiichi Nuclear Power Plant accident including: daily Japanese weather forecasts and atmospheric transport predictions to inform planning for field monitoring operations and to provide U.S. government agencies with ongoing situational awareness of meteorological conditions; estimates of possible dose in Japan based on hypothetical U.S. Nuclear Regulatory Commission scenarios of potential radionuclide releases to support protective action planning for U.S. citizens; predictions of possible plume arrival times and dose levels at U.S. locations; and source estimation and plume model refinement based on atmospheric dispersion modeling and available monitoring data.

Evaluation of seismic design by students made after Fukushima Dai-ichi accident

International Nuclear Information System (INIS)

Sugiyama, Ken-ichiro

2012-01-01

The sense of anxiety for safety of nuclear power plants among people in Japan has not disappeared after Fukushima Dai-ichi accident because of a typical country with frequent earthquakes. The provision of information for seismic design in nuclear power plants prepared for easier comprehension is always required in any kind of study meetings for the social acceptance of nuclear power plants. In the present paper, the effect of the provision of information made an attempt for students in Hokkaido University is reported. (author)

NARAC Modeling During the Response to the Fukushima Dai-ichi Nuclear Power Plant Emergency

Energy Technology Data Exchange (ETDEWEB)

Sugiyama, G; Nasstrom, J S; Probanz, B; Foster, K T; Simpson, M; Vogt, P; Aluzzi, F; Dillon, M; Homann, S

2012-02-14

This paper summarizes the activities of the National Atmospheric Release Advisory Center (NARAC) during the Fukushima Dai-ichi nuclear power plant crisis. NARAC provided a wide range of products and analyses as part of its support including: (1) Daily Japanese weather forecasts and hypothetical release (generic source term) dispersion predictions to provide situational awareness and inform planning for U.S. measurement data collection and field operations; (2) Estimates of potential dose in Japan for hypothetical scenarios developed by the Nuclear Regulatory Commission (NRC) to inform federal government considerations of possible actions that might be needed to protect U.S. citizens in Japan; (3) Estimates of possible plume arrival times and dose for U.S. locations; and (4) Plume model refinement and source estimation based on meteorological analyses and available field data. The Department of Energy/National Nuclear Security Administration (DOE/NNSA) deployed personnel to Japan and stood up 'home team' assets across the DOE complex to aid in assessing the consequences of the releases from the Fukushima Dai-ichi Nuclear Power Plant. The DOE Nuclear Incident Team (NIT) coordinated response activities, while DOE personnel provided predictive modeling, air and ground monitoring, sample collection, laboratory analysis, and data assessment and interpretation. DOE deployed the Aerial Measuring System (AMS), Radiological Assistance Program (RAP) personnel, and the Consequence Management Response Team (CMRT) to Japan. DOE/NNSA home team assets included the Consequence Management Home Team (CMHT); National Atmospheric Release Advisory Center (NARAC); Radiation Emergency Assistance Center/Training Site (REAC/TS); and Radiological Triage. NARAC was activated by the DOE/NNSA on March 11, shortly after the Tohoku earthquake and tsunami occurred. The center remained on active operations through late May when DOE ended its deployment to Japan. Over 32 NARAC staff

NARAC Modeling During the Response to the Fukushima Dai-ichi Nuclear Power Plant Emergency

International Nuclear Information System (INIS)

Sugiyama, G.; Nasstrom, J.S.; Probanz, B.; Foster, K.T.; Simpson, M.; Vogt, P.; Aluzzi, F.; Dillon, M.; Homann, S.

2012-01-01

This paper summarizes the activities of the National Atmospheric Release Advisory Center (NARAC) during the Fukushima Dai-ichi nuclear power plant crisis. NARAC provided a wide range of products and analyses as part of its support including: (1) Daily Japanese weather forecasts and hypothetical release (generic source term) dispersion predictions to provide situational awareness and inform planning for U.S. measurement data collection and field operations; (2) Estimates of potential dose in Japan for hypothetical scenarios developed by the Nuclear Regulatory Commission (NRC) to inform federal government considerations of possible actions that might be needed to protect U.S. citizens in Japan; (3) Estimates of possible plume arrival times and dose for U.S. locations; and (4) Plume model refinement and source estimation based on meteorological analyses and available field data. The Department of Energy/National Nuclear Security Administration (DOE/NNSA) deployed personnel to Japan and stood up 'home team' assets across the DOE complex to aid in assessing the consequences of the releases from the Fukushima Dai-ichi Nuclear Power Plant. The DOE Nuclear Incident Team (NIT) coordinated response activities, while DOE personnel provided predictive modeling, air and ground monitoring, sample collection, laboratory analysis, and data assessment and interpretation. DOE deployed the Aerial Measuring System (AMS), Radiological Assistance Program (RAP) personnel, and the Consequence Management Response Team (CMRT) to Japan. DOE/NNSA home team assets included the Consequence Management Home Team (CMHT); National Atmospheric Release Advisory Center (NARAC); Radiation Emergency Assistance Center/Training Site (REAC/TS); and Radiological Triage. NARAC was activated by the DOE/NNSA on March 11, shortly after the Tohoku earthquake and tsunami occurred. The center remained on active operations through late May when DOE ended its deployment to Japan. Over 32 NARAC staff members

Demonstration of laser processing technique combined with water jet technique for retrieval of fuel debris at Fukushima Daiichi Nuclear Power Station

International Nuclear Information System (INIS)

Hanari, Toshihide; Takebe, Toshihiko; Yamada, Tomonori; Daido, Hiroyuki; Ishizuka, Ippei; Ohmori, Shinya; Kurosawa, Koichi; Sasaki, Go; Nakada, Masahiro; Sakai, Hideaki

2017-01-01

In decommissioning of Fukushima Daiichi Nuclear Power Station, a retrieval process of fuel debris in the Primary Containment Vessel by a remote operation is one of the key issues. In this process, prevention of spreading radioactive materials is one of the important considerations. Furthermore, an applicable technique to the process requires keeping of reasonable processing-efficiency. We propose to use the combined technique including a laser light and a water jet as a retrieval technique of the fuel debris. The laser processing technique combined with a repetitive pulsed water jet could perform an efficient retrieval processing. Our experimental result encourages us to promote further development of the technique towards a real application at Fukushima Daiichi Nuclear Power Station. (author)

Fukushima Daiichi Unit 1 power plant containment analysis using GOTHIC

International Nuclear Information System (INIS)

Ozdemir, Ozkan Emre; George, Thomas L.; Marshall, Mervin D.

2015-01-01

Highlights: • The inclusion of vent heat transfer had a significant impact on the overall containment response. • The vent heat transfer and condensation results in lower containment pressure. • The reduced gas transfer to the wetwell via the vents results in higher hydrogen concentration in the drywell. - Abstract: This paper is a part of Fukushima Technical Evaluation Project (EPRI, 2013a, 2014a, 2015) which investigates various aspects of the Fukushima Daiichi event using the GOTHIC code. The analysis takes advantage of the capability of GOTHIC to model certain aspects of the system geometry and behavior in more detail than typically considered in containment performance analysis. GOTHIC is a general purpose thermal hydraulics code that is used extensively in the nuclear industry for system design support, licensing support and safety analysis. It has the capability to model 3-dimensional flow behavior including the effects of turbulence, diffusion and buoyancy (EPRI, 2014b). This allows GOTHIC to be used in cases where mixing effects and stratification are important. The analysis presented here considers the events at Fukushima Daiichi Unit 1 (1F1) following the tsunami and leading up to the time of the hydrogen detonation in the 1F1 Reactor Building. The 1F1 MAAP5 Baseline Scenario (EPRI, 2013b) is used to define the steam, hydrogen and carbon-monoxide source terms from the primary system and the core concrete interaction. The model incorporates three dimensional modeling of the drywell, wetwell and connecting vent system that can predict the 3-dimensional flow patterns and the temperature and gas distributions. The model also includes leakage to the surrounding reactor building and the wetwell vent to the stack. The 3D containment model includes models for the heat transfer from the steam and gas in the drywell vent system to the torus room, wetwell gas space and pool. Inclusion of vent heat transfer had a significant impact on the overall containment

Estimation of marine source-term following Fukushima Dai-ichi accident

International Nuclear Information System (INIS)

Bailly du Bois, P.; Laguionie, P.; Boust, D.; Korsakissok, I.; Didier, D.; Fiévet, B.

2012-01-01

Contamination of the marine environment following the accident in the Fukushima Dai-ichi nuclear power plant represented the most important artificial radioactive release flux into the sea ever known. The radioactive marine pollution came from atmospheric fallout onto the ocean, direct release of contaminated water from the plant and transport of radioactive pollution from leaching through contaminated soil. In the immediate vicinity of the plant (less than 500 m), the seawater concentrations reached 68 000 Bq.L −1 for 134 Cs and 137 Cs, and exceeded 100 000 Bq.L −1 for 131 I in early April. Due to the accidental context of the releases, it is difficult to estimate the total amount of radionuclides introduced into seawater from data obtained in the plant. An evaluation is proposed here, based on measurements performed in seawater for monitoring purposes. Quantities of 137 Cs in seawater in a 50-km area around the plant were calculated from interpolation of seawater measurements. The environmental halftime of seawater in this area is deduced from the time-evolution of these quantities. This halftime appeared constant at about 7 days for 137 Cs. These data allowed estimation of the amount of principal marine inputs and their evolution in time: a total of 27 PBq (12 PBq–41 PBq) of 137 Cs was estimated up to July 18. Even though this main release may be followed by residual inputs from the plant, river runoff and leakage from deposited sediments, it represents the principal source-term that must be accounted for future studies of the consequences of the accident on marine systems. The 137 Cs from Fukushima will remain detectable for several years throughout the North Pacific, and 137 Cs/ 134 Cs ratio will be a tracer for future studies. Highlights: ► Fukushima Dai-ichi accident is the most important artificial radioactive release flux into the sea. ► Quantities of 137 Cs in seawater are deduced from individual measurements. ► Local concentrations in

Life as an evacuee after the Fukushima Daiichi nuclear power plant accident is a cause of polycythemia: the Fukushima Health Management Survey.

Science.gov (United States)

Sakai, Akira; Ohira, Tetsuya; Hosoya, Mitsuaki; Ohtsuru, Akira; Satoh, Hiroaki; Kawasaki, Yukihiko; Suzuki, Hitoshi; Takahashi, Atsushi; Kobashi, Gen; Ozasa, Kotaro; Yasumura, Seiji; Yamashita, Shunichi; Kamiya, Kenji; Abe, Masafumi

2014-12-23

The Great East Japan Earthquake and the Fukushima Daiichi nuclear disaster forced people to evacuate their hometowns. Many evacuees from the government-designated evacuation zone were forced to change their lifestyle, diet, exercise, and other personal habits. The Comprehensive Health Check (CHC), 1 of 4 detailed surveys of The Fukushima Health Management Survey (FHMS), was implemented to support the prevention of lifestyle-related disease. The aim of this study was to analyze changes in red blood cell count (RBC), hemoglobin (Hb) levels, and hematocrit (Ht) levels by comparing data from the medical health checkup before and after the disaster in individuals who were 40 years old or older. Subjects in this study were Japanese men and women living in the vicinity of the Fukushima Daiichi Nuclear Power Plant in Fukushima prefecture. Annual health checkups with a focus on metabolic syndrome for insured persons/dependents aged 40 or older by Health Care Insurers have been conducted since 2008. All analyses in this study were limited to men and women aged 40-90 years. Changes in RBC, Hb levels, Ht levels, and prevalence of polycythemia before and after the disaster were compared. First, RBC, Hb, and Ht significantly increased in both men and women evacuees. The evacuation was significantly associated with increased Hb levels after adjustment for age, gender, smoking status, excess ethanol intake, BMI, and baseline Hb level (β = 0.16, p < 0.001). Furthermore, the prevalence of polycythemia stratified by smoking status or obesity also increased in the evacuee group. To our knowledge, this is the first report revealing that the evacuation was associated with the risk of polycythemia. This information could be very important for periodic health checkup and lifestyle recommendations for evacuees in the future.

Experimental investigation on molten pool representing corium composition at Fukushima Daiichi nuclear power plant

Energy Technology Data Exchange (ETDEWEB)

An, Sang Mo, E-mail: sangmoan@kaeri.re.kr [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yueong-gu, Daejeon, 305-353 (Korea, Republic of); Song, Jin Ho [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yueong-gu, Daejeon, 305-353 (Korea, Republic of); Kim, Jong-Yun [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yueong-gu, Daejeon, 305-353 (Korea, Republic of); Radiochemistry & Nuclear Nonproliferation, University of Science & Technology, Gajeong-ro 217, Yuseong-gu, Daejeon, 34113 (Korea, Republic of); Kim, HwanYeol [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yueong-gu, Daejeon, 305-353 (Korea, Republic of); Naitoh, Masanori [The Institute of Applied Energy, 1-14-2 Nishi-shimbashi, 1-Chome, Minato-ku, Tokyo, 105-0003 (Japan)

2016-09-15

A configuration of molten core in the Fukushima Daiichi NPP (nuclear power plant) was investigated by a melting and solidification experiment. About 5 kg of a mixture, whose composition in terms of weight is UO{sub 2} (60%), Zr + ZrO{sub 2} (25%), stainless steel (14%), B{sub 4}C (1%), was melted in a cold crucible using an induction heating technique. It was shown that the solidified melt consists of upper crust and lower solidified ingot. The solidified ingot was separated into two layers. A physical and chemical analysis was performed for the samples taken from the solidified melt to investigate the morphology and chemical characteristics. It was found that the solidified ingot consists of a metal-rich layer on the top and an oxide-rich layer at the bottom. In addition, the oxide layer at the bottom has composition close to the initial charge composition and surrounded by a thin crust layer. It turned out that B{sub 4}C was more concentrated in the upper metal-rich layer. These findings provide important insights for understanding the core melt progression and taking proper post-accident recovery actions for the Fukushima Daiichi NPP. - Highlights: • A configuration of molten core in the Fukushima Daiich NPP unit 1 is investigated. • Corium ingot consists of metallic layer on the top and oxidic layer at the bottom. • Boron carbide was more concentrated in the upper metallic layer. • Two layered configuration would contribute to the post-accident recovery actions.

Changing information needs of social impact of nuclear power plant siting. Through a comparison before and after the Fukushima Daiichi nuclear power plant accident

International Nuclear Information System (INIS)

Kashiwa, Takako; Kawamoto, Yoshimi

2013-01-01

In the light of the Fukushima Daiichi nuclear power plant accident, we need to consider a symbiosis method based on the diminution of the nuclear power industry. To find a region that does not excessively depend on the nuclear power industry, it is necessary to examine and discuss the social impact of nuclear-related industries. In this study, we compared people's changing information needs of social impact before and after the Fukushima Daiichi nuclear power plant accident. It was found that the need for information increased after the accident. In particular, there were three research areas where the need for information increased: the consideration of building nuclear power plants, the influence of harmful rumors on the region, and influence on the nuclear power industry. Next, attempts were made to understand whether there is a difference between information needs of social impact by attributes, such as age, sex and knowledge of nuclear power. The information needs of the following categories of people increased after the accident: people aged between 10 and 50 years, women, people who do not have a clear opinion about the use of a nuclear power plant, and people who do not have any knowledge of nuclear power. (author)

Evaluation of averted doses to members of the Public by tap water restrictions after the Fukushima Daiichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Kinase, Sakae; Kimura, Masanori; Hato, Shinji

2014-01-01

The effectiveness of urgent protective measures such as tap water restrictions and bottled water supplies in the early stage of an emergency exposure situation was studied after the Fukushima Daiichi nuclear power plant accident. Temporal changes in the concentration of an important radionuclide –iodine 131– in tap water were analyzed using published data in Fukushima, Ibaraki and Tokyo. Averted doses to members of the public due to chronic intakes of iodine 131 through tap water restrictions were also evaluated using an internal dose calculation code, DSYS-chronic code. In addition, the costs of bottled water supplies were calculated approximately. Consequently, it was found that the apparent half-life of iodine 131 in tap water was 2.8±1.2 days. The averted equivalent doses to the thyroid of members of the public –1-year-old children– were found to have a maximum value of 8.2 mSv in a local area of Fukushima. In comparison with Fukushima, the bottled water supplies might be a large sum of money regardless of the low doses in Tokyo. In conclusion, apart from the bottled water supplies, the tap water restrictions implemented by the authorities would be effective after the Fukushima Daiichi nuclear power plant accident. (author)

Consequences of Fukushima 11032011 - Radiological consequences from the nuclear accidents in Fukushima on 11 March 2011; Fukushima Auswirkung 11032011 -- Radiologische Auswirkungen aus den kerntechnischen Unfaellen in Fukushima vom 11.03.2011

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-12-15

On 11 March 2011 at 14.46 the strongest earthquake ever recorded in Japan struck the Pacific coast in front of Fukushima. The earthquake and the following tsunami damaged the nuclear power plants in Fukushima Dai-ichi to such an extent that the Japanese government declared the state of catastrophic accident with degree 7 according to the International Nuclear and Radiological Event Scale (INES). At Fukushima Dai-ichi there were 6 boiling water reactors (BWR), a storage pool for spent fuel assemblies and a dry cask storage. 12 km apart at Fukushima Dai-ni there were 4 more BWR. At the moment of the earthquake the reactors 1 to 3 of Fukushima Dai-ichi, as well as the 4 reactors at Fukushima Dai-ni, were at full power, while the reactors 4 to 6 of Fukushima Dai-ichi were shut down for revision. From 12 March 2011 on, fairly large quantities of radioactive materials were released from Fukushima Dai-ichi reactors with meaningful consequences on the population in the near neighbourhood. The irradiation from the radioactivity bearing clouds, the ingestion and inhalation, and the deposit of radioactive materials on the ground threatened the population. The inhabitants of large areas had to be evacuated. Furthermore, radioactive materials contaminated the drinking water, the sea water and finally the plants and animals, i.e. the food chain of the people living there. The Swiss Federal Nuclear Safety Inspectorate (ENSI) continuously proceeded with the evaluation of the situation in Japan and a specialists' team made a detailed analysis of the accident, with emphasis on the human and organisational factors and on the lessons learned from this. The present report describes the present knowledge about the radiological consequences of the accident in Fukushima Dai-ichi on the population in the neighbourhood and on the staff at the power plant, until October 2011. First, the unrolling of the accident and its consequences on the plant site are analysed according to

The Fukushima Daiichi Accident. Technical Volume 3/5. Emergency Preparedness and Response

International Nuclear Information System (INIS)

2015-08-01

This volume describes the key events and response actions from the onset of the accident at the Fukushima Daiichi nuclear power plant (NPP), operated by the Tokyo Electric Power Company (TEPCO), on 11 March 2011. It also describes the national emergency preparedness and response (EPR) system in place in Japan and the international EPR framework prior to the accident. It is divided into five sections. Section 3.1 describes the initial actions taken by Japan in response to the accident, involving: identification of the accident, notification of off-site authorities and activation of the response; mitigatory actions taken on-site; and initial off-site response. Section 3.2 describes the protective measures taken for personnel in response to the natural disaster, protection of emergency workers, medical management of emergency workers and the voluntary involvement of members of the public in the emergency response. Section 3.3 describes the protective actions and other response actions taken by Japan to protect the public. It addresses urgent and early protective actions; the use of a dose projection model, the System for Prediction of Environmental Emergency Dose Information (SPEEDI), as a basis for decisions on protective actions during the accident; environmental monitoring; provision of information to the public and international community; and issues related to international trade and waste management. Section 3.4 describes the transition from the emergency phase to the recovery phase. It also addresses the national analysis of the accident and the emergency response. Section 3.5 describes the response by the IAEA, other international organizations within the Inter- Agency Committee on Radiological and Nuclear Emergencies (IACRNE), the actions of IAEA Member States with regard to protective actions recommended to their nationals in Japan and the provision of international assistance. A summary, observations and lessons conclude each section. There are three

The Fukushima Daiichi Accident. Technical Volume 1/5. Description and Context of the Accident. Annexes

International Nuclear Information System (INIS)

2015-08-01

The Fukushima Daiichi Accident consists of a Report by the IAEA Director General and five technical volumes. It is the result of an extensive international collaborative effort involving five working groups with about 180 experts from 42 Member States with and without nuclear power programmes and several international bodies. It provides a description of the accident and its causes, evolution and consequences, based on the evaluation of data and information from a large number of sources available at the time of writing. The Fukushima Daiichi Accident will be of use to national authorities, international organizations, nuclear regulatory bodies, nuclear power plant operating organizations, designers of nuclear facilities and other experts in matters relating to nuclear power, as well as the wider public. The set contains six printed parts and five supplementary CD-ROMs. Contents: Report by the Director General; Technical Volume 1/5, Description and Context of the Accident; Technical Volume 2/5, Safety Assessment; Technical Volume 3/5, Emergency Preparedness and Response; Technical Volume 4/5, Radiological Consequences; Technical Volume 5/5, Post-accident Recovery; Annexes. The Report by the Director General is available separately in Arabic, Chinese, English, French, Russian, Spanish and Japanese

Cooperation between National Defense Medical College and Fukushima Medical University in thyroid ultrasound examination after the Fukushima Daiichi nuclear power plant disaster

International Nuclear Information System (INIS)

Yamamoto, Yoritsuna; Fujita, Masanori; Tachibana, Shoich; Morita, Koji; Hamano, Kunihisa; Hamada, Koji; Uchida, Kosuke; Tanaka, Yuji

2013-01-01

Fukushima Daiichi Nuclear Power Plant was utterly destroyed by The Great East Japan Earthquake which happened on March 11, 2011, and followed by radioactive contamination to the surrounding areas. Based on the known radioactive iodine ("1"3"1I) which led to thyroid cancer in children after the Chernobyl nuclear power plant disaster in 1986, children living in Fukushima should be carefully observed for the development of thyroid cancer. Fukushima Prefecture and Fukushima Medical University started ''Fukushima Health Management Survey'' in May 2011, which includes screening for thyroid cancer by ultrasonography (Thyroid Ultrasound Examination). Thyroid Ultrasound Examination would cover roughly 360,000 residents aged 0 to 18 years of age at the time of the nuclear disaster. The initial screening is to be performed within the first three years after the accident, followed by complete thyroid examinations from 2014 onwards, and the residents will be monitored regularly thereafter. As Thyroid Ultrasound Examination is being mainly performed by medical staff at Fukushima Medical University, there is insufficient manpower to handle the large number of potential examinees. Thus, specialists of thyroid diseases from all over Japan have begun to support this examination. Six endocrinologists including the authors belonging to the National Defense Medical College are cooperating in part of this examination. This paper briefly reports the outline of Thyroid Ultrasound Examination and our cooperation. (author)

Pregnancy and birth survey after the Great East Japan Earthquake and Fukushima Daiichi Nuclear Power Plant accident in Fukushima prefecture.

Science.gov (United States)

Fujimori, Keiya; Kyozuka, Hyo; Yasuda, Shun; Goto, Aya; Yasumura, Seiji; Ota, Misao; Ohtsuru, Akira; Nomura, Yasuhisa; Hata, Kenichi; Suzuki, Kouta; Nakai, Akihito; Sato, Mieko; Matsui, Shiro; Nakano, Kyoko; Abe, Masafumi

2014-01-01

On 11 March 2011, the Great East Japan Earthquake followed by a powerful tsunami hit the Pacific Coast of Northeast Japan and damaged Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Plant, causing a radiation hazard in Fukushima Prefecture. The objective of this report is to describe some results of a questionnaire-based pregnancy and birth survey conducted by the Radiation Medical Science Center for the Fukushima Health Management Survey. Questionnaires were sent to women who received maternal and child health handbooks from municipal officers in Fukushima Prefecture between 1 August 2010 and 31 July 2011, with the aim of reaching those who were pregnant at the time of the disaster. Mailing began 18 January 2012. Data were analyzed separately for six geographic areas in Fukushima Prefecture. The total number of women meeting survey criteria was 15,972. The number of responses received to date is 9,298 (58.2%). Data from 8602 respondents were analyzed after excluding 634 invalid responses and 5 induced and 57 spontaneous abortions (less than 22 gestational weeks). The incidences of stillbirth (over 22 completed gestational weeks), preterm birth, low birth weight and congenital anomalies were 0.25%, 4.4%, 8.7% and 2.72%, respectively. These incidences are similar to recent averages elsewhere in Japan. Considering the pregnancy and birth survey data in aggregate, our disaster seemed to provoke no significant adverse outcomes over the whole of Fukushima prefecture. But post-disaster prenatal care and support intended for patients' safety and security should be coupled with ongoing surveillance and rigorous data analysis.

Internal radiation dose of KURRI volunteers working at evacuation shelters after TEPCO's Fukushima Daiichi nuclear power plant accident

International Nuclear Information System (INIS)

Kurihara, Kouta; Kinashi, Yuko; Okamoto, Kenichi

2013-01-01

We report the radiation doses encountered by 59 Kyoto University Research Reactor Institute (KURRI) staff members who had been dispatched to screen refugees for radiation at emergency evacuation sites 45-80 km from the Tokyo Electric Power Co.'s (TEPCO's) Fukushima Daiichi nuclear power plant. From March 20 to April 30, 2011, 42 members in teams consisting of 2-4 staff members were dispatched 15 times to 7 emergency evacuation sites located 45-80 km from the power plant to examine the radioactive contamination affecting refugees. Continuously, from May 10 to May 23, 2011, 17 members in teams consisting of 2-5 staff members were dispatched 6 times to Fukushima Prefecture to establish the Kyoto University Radiation Mapping (KURAMA) system. Internal burdens of radioactive nuclides were estimated using a whole-body counter consisting of an iron room, NaI (Tl) scintillation detectors, and a digital multichannel analyzer (MCA7600; Seiko EG and G). The calibration of the whole-body counter and the conversion of the measured body burden to the committed effective dose by internal exposure were carried out in accordance with the Nuclear Safety Research Association (NSRA) technical manual. The external radiation dose to each staff member was measured using a personal dosimeter. The first dispatched team showed 1300-1929 Bq of internal radiation activity from cesium (including "1"3"7Cs and "1"3"4Cs) and 48-118 Bq of "1"3"1I. The internal doses of four members of the first team were estimated to be 24-39 μSv. The doses from internal exposure were almost similar to the cumulative external doses for the dispatch period (March 20-22, 2011) when the radiation plumes following the explosions of Units 1 and 3 in TEPCO's Fukushima Daiichi nuclear plant had diffused around Fukushima City. The external radiation doses of members dispatched after the second team had decreased from one-third to less than one-tenth of the external doses of the first dispatched team. The internal

Internal radiation dose of KURRI volunteers working at evacuation shelters after TEPCO's Fukushima Daiichi nuclear power plant accident

International Nuclear Information System (INIS)

Kurihara, Kouta; Kinashi, Yuko; Okamoto, Kenichi

2012-01-01

We report the radiation doses encountered by 59 Kyoto University Research Reactor Institute (KURRI) staff members who had been dispatched to screen refugees for radiation at emergency evacuation sites 45–80 km from the Tokyo Electric Power Co.’s (TEPCO’s) Fukushima Daiichi nuclear power plant. From March 20 to April 30, 2011, 42 members in teams consisting of 2–4 staff members were dispatched 15 times to 7 emergency evacuation sites located 45–80 km from the power plant to examine the radioactive contamination affecting refugees. Continuously, from May 10 to May 23, 2011, 17 members in teams consisting of 2–5 staff members were dispatched 6 times to Fukushima Prefecture to establish the Kyoto University Radiation Mapping (KURAMA) system. Internal burdens of radioactive nuclides were estimated using a whole-body counter consisting of an iron room, NaI (Tl) scintillation detectors, and a digital multichannel analyzer (MCA7600; Seiko EG and G). The calibration of the whole-body counter and the conversion of the measured body burden to the committed effective dose by internal exposure were carried out in accordance with the Nuclear Safety Research Association (NSRA) technical manual. The external radiation dose to each staff member was measured using a personal dosimeter. The first dispatched team showed 1300–1929 Bq of internal radiation activity from cesium (including "1"3"7Cs and "1"3"4Cs) and 48–118 Bq of "1"3"1I. The internal doses of four members of the first team were estimated to be 24–39 μSv. The doses from internal exposure were almost similar to the cumulative external doses for the dispatch period (March 20–22, 2011) when the radiation plumes following the explosions of Units 1 and 3 in TEPCO’s Fukushima Daiichi nuclear plant had diffused around Fukushima City. The external radiation doses of members dispatched after the second team had decreased from one-third to less than one-tenth of the external doses of the first dispatched team

Aftermath of the Fukushima Daiichi nuclear accident in March 2011 - Situation review in March 2016

International Nuclear Information System (INIS)

2016-03-01

The first part of this detailed report addresses the consequences of the accident regarding nuclear safety. It proposes a situation review of site damaged installations, of radioactive water management, and of underground water management. It presents and comments lessons learned from this accident for French nuclear installations, gives an overview of researches performed by the IRSN in the field of nuclear safety. The second part addresses health consequences of the accident. It discusses an assessment of epidemiologic studies performed on inhabitants of the Fukushima Prefecture, and comments the situation of workers involved in operations performed in the Fukushima Daiichi nuclear power plant. The third part addresses environmental consequences. It discusses values of radionuclide concentrations in Japanese air five years after the accident, measurements of caesium activities, assessments of contamination of Japanese food products, decontamination actions and waste management, the status of marine contamination in 2015, the evolution of evacuation areas between 2011 and 2016, the first returns and wills to return of evacuated populations, the update of knowledge related to the dispersion and depositions of atmospheric releases of the accident, and the modelling of atmospheric transport and fallouts of releases emitted during the accident. The last part proposes a comparison between the Chernobyl accident and the Fukushima accident in terms of distribution of radioactive depositions within river basins, of knowledge drawn from ecologic studies on fauna and flora performed on the long term in contaminated areas, and of management of forest environments after a nuclear accident

Abbreviations [Annex to The Fukushima Daiichi Accident, Technical Volume 5/5

International Nuclear Information System (INIS)

2015-01-01

This annex is a list of abbreviations used in the publication The Fukushima Daiichi Accident, Technical Volume 5/5. The list includes the abbreviations for: • General Safety Requirements; • International Commission on Radiological Protection; • Intensive Contamination Survey Area; • International Experts Meeting; • Ministry of Education, Culture, Sports, Science and Technology; • Ministry of the Environment; • Nuclear Damage Compensation and Decommissioning Facilitation Corporation; • Nuclear Emergency Response Headquarters; • nuclear power plant; • Nuclear Safety Commission; • OECD Nuclear Energy Agency; • Special Decontamination Area; • Specific Safety Requirements; • technical cooperation; • Three Mile Island; • United Nations Scientific Committee on the Effects of Atomic Radiation

In-core monitor housing replacement at Fukushima Daiichi Unit No.4

International Nuclear Information System (INIS)

Arai, Tomoyuki

1999-01-01

The in-core monitor (ICM) housing replacement of a Boiling Water Reactor (BWR) has been completed at Fukushima-Daiichi Unit No. 4 (1F4) of the Tokyo Electric Power Company (TEPCO) in Japan. Since cracking of the inside surface of an ICM housing was found in this unit, the ICM housing was replaced with one made of low-carbon stainless steel (SS) to improve Intergranular Stress Corrosion Cracking (IGSCC) resistance. This project is the first application of the replacement procedure for the ICM housing and employs various advanced technologies. The outline of the ICM housing replacement project and applied technologies are discussed in this paper. (author)

Review of Cytogenetic analysis of restoration workers for Fukushima Daiichi nuclear power station accident

International Nuclear Information System (INIS)

Suto, Yumiko

2016-01-01

Japan faced with the nuclear accident of the Fukushima Daiichi Nuclear Power Station (NPS) caused by the combined disaster of the Great East Japan Earthquake and the subsequent tsunamis on 11 March 2011. National Institute of Radiological Sciences received all nuclear workers who were engaged in emergency response tasks at the NPS and suspected of being overexposed to acute radiation. Biological dosimetry by dicentric chromosome assay was helpful for medical triage and management of the workers. When an unplanned radiation exposure occurs, biological dosimetry based on cytogenetic assays has been used to estimate the absorbed dose in the exposed individual to get useful information for the medical management of radiological casualties with suspected acute radiation syndrome (ARS). Nowadays, more cytogenetic assays to measure chromosomal aberrations, such as micronuclei in bi-nucleated cells, prematurely condensed chromosomes (PCCs) and inter-chromosomal exchanges detected by fluorescence in situ hybridization (FISH) techniques, are available. However, the dicentric chromosome assay (DCA) using peripheral blood lymphocytes is still considered to be the 'gold standard' of biological dosimetry for the radiation emergency medicine. Experimental protocols of DCA has been standardized and shared among laboratories all over the world. In fact, DCA was useful in previous radiation accidents, e.g. the Chernobyl accident in 1986, the Goiania accident in 1987, the JCO criticality accident in 1999 and the Tokyo electric power company (TEPCO) Fukushima Daiichi Nuclear Power Station (NPS) accident in 2011. The recent development of microscopic image analysis system with automatic metaphase finding and capturing functions was helpful for rapid detection of dicentric chromosomes to perform DCA for the Fukushima NPS restoration workers. (author)

US Efforts in Support of Examinations at Fukushima Daiichi - 2016 Evaluations

International Nuclear Information System (INIS)

Amway, P.; Andrews, N.; Bixby, Willis; Bunt, R.; Corradini, M.; Ellison, P.; Farmer, M.; Farthing, T.; Francis, M; Gabor, J.; Gauntt, R.; Henry, C.; Humrickhouse, P.; Kraft, S.; Linthicum, R.; Luangdilok, W.; Lutz, R.; Luxat, D.; Maddox, J.; Negin, C.; Paik, C.; Plys, M.; Rempe, J.; Robb, K.; Sanders, R.; Wachowiak, R.; Williamson, B.

2016-01-01

Although it is clear that the accident signatures from each unit at the Fukushima Daiichi Nuclear Power Station (NPS) [Daiichi] differ, much is not known about the end-state of core materials within these units. Some of this uncertainty can be attributed to a lack of information related to cooling system operation and cooling water injection. There is also uncertainty in our understanding of phenomena affecting: a) in-vessel core damage progression during severe accidents in boiling water reactors (BWRs), and b) accident progression after vessel failure (ex-vessel progression) for BWRs and Pressurized Water Reactors (PWRs). These uncertainties arise due to limited full scale prototypic data. Similar to what occurred after the accident at Three Mile Island Unit 2, these Daiichi units offer the international community a means to reduce such uncertainties by obtaining prototypic data from multiple full-scale BWR severe accidents. Information obtained from Daiichi is required to inform Decontamination and Decommissioning activities, improving the ability of the Tokyo Electric Power Company Holdings (TEPCO) to characterize potential hazards and to ensure the safety of workers involved with cleanup activities. This document reports recent results from the US Forensics Effort to use information obtained by TEPCO to enhance the safety of existing and future nuclear power plant designs. This Forensics Effort, which is sponsored by the Reactor Safety Technologies Pathway of the Department of Energy Office of Nuclear Energy Light Water Reactor (LWR) Sustainability Program, consists of a group of US experts in LWR safety and plant operations that have identified examination needs and are evaluating TEPCO information from Daiichi that address these needs. Examples presented in this report demonstrate that significant safety insights are being obtained in the areas of component performance, fission product release and transport, debris end-state location, and combustible gas

Telephone counseling for the public after the Fukushima Daiichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Horiguchi, T.; Kojima, K.; Itoh, T.

2011-01-01

After the Fukushima Daiichi Nuclear Power Plant accident, Kinki University Atomic Energy Research Institute provided telephone counseling services in order to respond the public's growing concerns about radiation and nuclear energy. Three telephone lines were newly installed for the counseling and the number of consultation marked 705 between March 24 and April 2. In this report, by summarizing the contents of the counseling, we will show what the public concerned about shortly after the accident and report how we responded to the concerns. (author)

Additional examination on station blackout caused by tsunami in Fukushima Daiichi NPS

International Nuclear Information System (INIS)

Yamauchi, Daisuke; Date, Kenji; Mizokami, Masato; Honda, Takeshi; Nozaki, Kenichiro; Mizokami, Shinya; Endo, Ryohei

2017-01-01

This study is additional examination to verify in a more reliable way the assessment that the emergency AC power supply was lost due to tsunami at Fukushima Daiichi Nuclear Power Station. It confirmed the relationship between the path length of tsunami intrusion reaching each power supply facility and the function loss time. As a result of examination, it was confirmed that as the path length of the tsunami intrusion reaching each power supply facility was longer, the function loss time tended to be later. So, conventional assessment that the function of each power supply facility was lost due to the run-up and flooding of tsunami has become more probable. For facilities, where the overall trend and the loss time of function were divergent, it was found that there were scenarios that could reasonably be explained. Based on the fact that the Fukushima Daiichi Nuclear Power Station lost power due to the tsunami, Kashiwazaki-Kariwa Nuclear Power Station carries out various safety measures. First of all, as the measures to prevent accidents caused by tsunami, the following have been applied: (1) prevention of the inflow of tsunamis into premises, (2) water prevention of the areas installed with important equipment, (3) securement of seawater at the time of backwashing, (4) storage of portable equipment at high ground, (5) installation of tsunami surveillance cameras. To prepare for the loss of power supply, this station implemented power supply facilities such as generator cars and distribution boards, as well as the placement of power supply cars at high ground. (A.O.)

Monitoring of Radionuclide Contamination in Food Samples in Malaysia due to Daiichi Reactor Accident in Fukushima, Japan

International Nuclear Information System (INIS)

Nurrul Assyikeen Mohd Jaffary; Abdul Kadir Ishak; Wo, Y.M.

2011-01-01

On March 11, 2011, a serious accident occurred in Daiichi nuclear reactor plant, Fukushima, Japan which caused radioactive materials been released into the atmosphere in the form of aerosols and dust particles. Sea water around the plant was also found contaminated with high radioactivity readings. These radioactive materials could be transported by the winds and ocean current across international borders and cannot be controlled by human. Besides a continuous monitoring activity of radionuclide content in the air and sea water that need to be conducted by the authorities, Malaysia should also control the entry of radionuclide through contaminated food ingestion by human. Radionuclide I-131, Cs-134 and Cs-137 were used as a counter-measure of pollution levels and counted with gamma spectrometry using standard analysis method suggested by AOAC International. In this paper, details description of the role of Radiochemical and Environment Group, Nuclear Malaysia who's responsible in analyzing the radioactivity in the food samples due to Fukushima Daiichi, Japan accident was included. Also discussed are the radioactivity limit adopted and analysis results from this monitoring. (author)

The Fukushima Dai-ichi Accident and its implications for the safety of nuclear power

Science.gov (United States)

Barletta, William

2016-05-01

Five years ago the dramatic events in Fukushima that followed the massive earthquake and subsequent tsunami that struck Japan on March 11, 2011 sharpened the focus of scientists, engineers and general public on the broad range of technical, environmental and societal issues involved in assuring the safety of the world's nuclear power complex. They also called into question the potential of nuclear power to provide a growing, sustainable resource of CO2-free energy. The issues raised by Fukushima Dai-ichi have provoked urgent concern, not only because of the potential harm that could result from severe accidents or from intentional damage to nuclear reactors or to facilities involved in the nuclear fuel cycle, but also because of the extensive economic impact of those accidents and of the measures taken to avoid them.

Accident analysis of Fukushima Daiichi Nuclear Power Station unit 1

International Nuclear Information System (INIS)

Kobayashi, Masahide; Narabayashi, Tadashi; Tsuji, Masashi; Chiba, Go; Nagata, Yasunori; Shimoe, Tomohiro

2015-01-01

As a result of the Great East Japan Earthquake that occurred on 11 March 2011, all AC and DC power at the Fukushima Daiichi NPP units 1 to 3 were lost soon after the tsunami. The core cooling function was lost, and the cores of units 1 to 3 were damaged. The purpose of this work is to clarify the progress of the accident in unit 1, which was damaged the earliest among the 3 units. Therefore, an original severe accident analysis code was developed, and the progress of the accident was evaluated from the analysis results and the actual data. As a result, the leakage path from a pressure vessel was clarified, and some lessons and knowledge were gained. (author)

Analytics of Radioactive Materials Released in the Fukushima Daiichi Nuclear Accident

Energy Technology Data Exchange (ETDEWEB)

Egarievwe, Stephen U. [Nuclear Engineering and Radiological Science Center, Alabama A and M University, Huntsville, AL (United States); Nuclear Engineering Department, University of Tennessee, Knoxville, TN (United States); Coble, Jamie B.; Miller, Laurence F. [Nuclear Engineering Department, University of Tennessee, Knoxville, TN (United States)

2015-07-01

The 2011 Fukushima Daiichi nuclear accident in Japan resulted in the release of radioactive materials into the atmosphere, the nearby sea, and the surrounding land. Following the accident, several meteorological models were used to predict the transport of the radioactive materials to other continents such as North America and Europe. Also of high importance is the dispersion of radioactive materials locally and within Japan. Based on the International Atomic Energy Agency (IAEA) Convention on Early Notification of a nuclear accident, several radiological data sets were collected on the accident by the Japanese authorities. Among the radioactive materials monitored, are I-131 and Cs-137 which form the major contributions to the contamination of drinking water. The radiation dose in the atmosphere was also measured. It is impractical to measure contamination and radiation dose in every place of interest. Therefore, modeling helps to predict contamination and radiation dose. Some modeling studies that have been reported in the literature include the simulation of transport and deposition of I-131 and Cs-137 from the accident, Cs-137 deposition and contamination of Japanese soils, and preliminary estimates of I-131 and Cs-137 discharged from the plant into the atmosphere. In this paper, we present statistical analytics of I-131 and Cs-137 with the goal of predicting gamma dose from the Fukushima Daiichi nuclear accident. The data sets used in our study were collected from the IAEA Fukushima Monitoring Database. As part of this study, we investigated several regression models to find the best algorithm for modeling the gamma dose. The modeling techniques used in our study include linear regression, principal component regression (PCR), partial least square (PLS) regression, and ridge regression. Our preliminary results on the first set of data showed that the linear regression model with one variable was the best with a root mean square error of 0.0133 μSv/h, compared

Analytics of Radioactive Materials Released in the Fukushima Daiichi Nuclear Accident

International Nuclear Information System (INIS)

Egarievwe, Stephen U.; Coble, Jamie B.; Miller, Laurence F.

2015-01-01

The 2011 Fukushima Daiichi nuclear accident in Japan resulted in the release of radioactive materials into the atmosphere, the nearby sea, and the surrounding land. Following the accident, several meteorological models were used to predict the transport of the radioactive materials to other continents such as North America and Europe. Also of high importance is the dispersion of radioactive materials locally and within Japan. Based on the International Atomic Energy Agency (IAEA) Convention on Early Notification of a nuclear accident, several radiological data sets were collected on the accident by the Japanese authorities. Among the radioactive materials monitored, are I-131 and Cs-137 which form the major contributions to the contamination of drinking water. The radiation dose in the atmosphere was also measured. It is impractical to measure contamination and radiation dose in every place of interest. Therefore, modeling helps to predict contamination and radiation dose. Some modeling studies that have been reported in the literature include the simulation of transport and deposition of I-131 and Cs-137 from the accident, Cs-137 deposition and contamination of Japanese soils, and preliminary estimates of I-131 and Cs-137 discharged from the plant into the atmosphere. In this paper, we present statistical analytics of I-131 and Cs-137 with the goal of predicting gamma dose from the Fukushima Daiichi nuclear accident. The data sets used in our study were collected from the IAEA Fukushima Monitoring Database. As part of this study, we investigated several regression models to find the best algorithm for modeling the gamma dose. The modeling techniques used in our study include linear regression, principal component regression (PCR), partial least square (PLS) regression, and ridge regression. Our preliminary results on the first set of data showed that the linear regression model with one variable was the best with a root mean square error of 0.0133 μSv/h, compared

WHO's public health agenda in response to the Fukushima Daiichi nuclear accident

International Nuclear Information System (INIS)

Van Deventer, Emilie; Del Rosario Perez, Maria; Carr, Zhanat; Tritscher, Angelika; Fukushima, Kazuko

2012-01-01

The World Health Organization (WHO) has responded to the 2011 East-Japan earthquake and tsunami through the three levels of its decentralised structure. It has provided public health advice regarding a number of issues relating to protective measures, potassium iodide use, as well as safety of food and drinking water, mental health, travel, tourism, and trade. WHO is currently developing an initial health risk assessment linked to a preliminary evaluation of radiation exposure around the world from the Fukushima Daiichi nuclear accident. Lessons learned from this disaster are likely to help future emergency response to multi-faceted disasters. (note)

Cs-134 and Cs-137 radioactivity in river waters in Fukushima, Miyagi, Ibaraki and Gunma Prefectures in August 2012 after the Fukuhsima Daiichi Nuclear Power Plant accident

Energy Technology Data Exchange (ETDEWEB)

Nagao, S.; Ochiai, S.; Yamamoto, M. [Low Level Radioactivity Laboratory, Institute of Nature and Environmental Technology, Kanazawa University, Wake, Nomi, Ishikawa 923-1224(Japan); Kanamori, M. [Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 921-1192 (Japan); Tomihara, S. [Environmental Aquarium Aquamarine Fukushima, 50 Tatsumi, Onahama, Iwaki, Fukushima 971-8101(Japan); Suzuki, K. [Gunma Prefectural Fisheries Experimental Station, 13 Shikishima, Maebashi, Gunma 371-1036 (Japan)

2014-07-01

About 15 PBq from both {sup 134}Cs and {sup 137}Cs were released from the Fukushima Dai-ichi Nuclear Power Plant (NPP) because of venting operations and hydrogen explosions. The Ministry of Education, Culture, Sports, Science and Technology of Japan reported total surface deposition of {sup 134}Cs and {sup 137}Cs in Japan. To estimate short-term and long-term impacts of the radiation dose in Japan, it is important to understand the dynamics of radionuclides, especially those of {sup 134}Cs and {sup 137}Cs, on river watershed environments. This study investigated {sup 134}Cs and {sup 137}Cs radioactivity in river systems in Fukushima, Miyagi, Ibaraki and Gunma prefectures, Japan. The secondary radioactive dispersion of radiocesium from the contaminated watershed to the river waters is reported for research areas with widely various radiocesium deposition on ground surfaces at 18 months after the accident. Field experiments were conducted at a fixed station in four rivers (the Uta, Niida, Natsui, and Same Rivers) in Fukushima Prefecture, and the Kuji River, and Naka River in Ibaraki Prefecture in August 2012. The Abukuma River was set up one site at the upper, two sites in the middle reach in Fukushima Prefecture and at one site in the lower area in Miyagi Prefecture. The Tone River system has three stations at the upper river area in Gunma Prefecture and one site at the lower reach in Ibaraki Prefecture. Surface deposition results reveals significant external radioactivity in a zone extending northwest from the NPP. However, a mountainous area in Gunma Prefecture, located about 220 km from Fukushima Dai-ichi NPP south of Fukushima Prefecture, shows similar accumulation of {sup 134}Cs and {sup 137}Cs. The 20 L of surface river waters were collected at the station using buckets. The radioactivity of {sup 134}Cs and {sup 137}Cs in the river waters was measured with gamma-ray spectrometry using ammonium molybdophosphate (AMP)/Cs compound method with a low background Ge

Radioactive contamination of arthropods from different trophic levels in hilly and mountainous areas after the Fukushima Daiichi nuclear power plant accident.

Science.gov (United States)

Tanaka, Sota; Hatakeyama, Kaho; Takahashi, Sentaro; Adati, Tarô

2016-11-01

In order to understand the influence of the Fukushima Daiichi nuclear power plant accident on the ecosystem in hilly and mountainous areas of Fukushima Prefecture, chronological changes in the levels of radiocesium in arthropod species were investigated. From 2012 to 2014, arthropods from different trophic levels were sampled and the air radiation dose rates at the sampling sites were analyzed. The air radiation dose rates showed a significant and constant reduction over the 2 years at the sampling sites in Fukushima. The median radiocesium concentration ( 134 Cs +  137 Cs) detected in the rice grasshopper, Oxya yezoensis, and the Emma field cricket, Teleogryllus emma, dropped continuously to 0.080 and 0.078 Bq/g fresh weight, respectively, in 2014. In contrast, no significant reduction in radioactive contamination was observed in the Jorô spider, Nephila clavata, in which the level remained at 0.204 Bq/g in 2014. A significant positive correlation between radiocesium concentration and the air radiation dose rate was observed in the rice grasshopper, the Emma field cricket and the Jorô spider. The highest correlation coefficient (ρ = 0.946) was measured in the grasshopper. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Atmospheric radionuclides from Fukushima Dai-ichi nuclear accident detected in Lanzhou, China

Institute of Scientific and Technical Information of China (English)

邬家龙王赟; 孙卫; 罗伟立; 王延俊; 张飙

2015-01-01

After the Fukushima Dai-ichi nuclear power plant accident on March 11, 2011, the radioactivity released from the accident was transported around the globe by atmospheric processes. The radioactivity monitoring program on atmospheric particulate in Lanzhou, China was activated by GSCDC to detect the input radionu-clides through atmospheric transport. Several artificial radionuclides were detected and measured in aerosol samples from March 26 to May 2, 2011. The peaked activity concentrations (in mBq/m3) were: 1.194 (131I), 0.231 (137Cs), 0.173 (134Cs) and 0.008 (136Cs), detected on April 6, 2011. The average activity ratio of 131I/137Cs and 134Cs/137Cs in air were 13.5 and 0.78. The significant increase of 137Cs activity concentration, one order of magnitude higher than pre-Fukushima accident levels, in ground level aerosol was observed in 2013, as its re-suspension from soil. The back-trajectory analysis simulated by NOAA-ARL HYSPLIT shows a direct transfer of the air masses released from Fukushima to Lanzhou across the Pacific Ocean, North America and Europe at the height close to 9000 m AGL. The value of effective dose for inhalation is close to one millionth of the annual limit for the general public.

[A Survey about the Radiation Effects and A Health Survey of Fukushima Inhabitants after the Fukushima Daiichi Nuclear Power Plant Accident].

Science.gov (United States)

Okazaki, Ryuji; Ohga, Kazuhiro; Yoko-O, Makoto; Kohzaki, Masaoki

According to questionnaire surveys in 2011 and 2013 about the health effects of radiation after the Fukushima Daiichi Nuclear Power Plant Accident, the guardians of child patients were more anxious than doctors and medical students. Also, according to the thyroid examinations in a Fukushima health survey, 190 cases of thyroid cancer were reported, and anxiety about radiation effects remained. This study is based on a survey about the guardians of child patients anxiety about radiation effects six years after the nuclear power plant accident, and includes a questionnaire survey about radiation effects and thyroid examinations in a Fukushima health survey. Anonymous question sheets with 20 questions were sent to pediatric medical facilities in Fukushima, and the parents of children who consulted the pediatric and medical staff answered the questionnaire. Thirty percent of the guardians of child patients had never been educated about radiation and 67% had never been educated about the effects of radiation on humans. The guardians of child patients were more anxious than the medical staff about thyroid cancer, health effects on children and genetic effects. Our results indicate that the guardians of child patients think that the increase in the incidence of thyroid cancer is due to radiation effects after the nuclear power plant accident and they desire continued thyroid examinations.

The second update of the Fukushima Daiichi Nuclear Station accident. June 1 through August 31, 2011

International Nuclear Information System (INIS)

Shibutani, Yu

2011-01-01

The Fukushima Daiichi accident occurred on March 11, 2011. The Japanese government and Tokyo Electric Power Company (TEPCO) encountered great deal of difficulties to stabilize the nuclear power reactor. Although the maximum radiation level has decreased, it still accounts for one-fifth of the level detected as of end of August 2011. There are currently growing concerns regarding the complexities of nuclear energy that are faced by the society of Japan. Owing to the occurrence of the Fukushima Daiichi accident, the firm belief on absolute safety of Japan's nuclear power plants has suddenly collapsed. Over the past decades, people tended to trust the government and electric power companies, which assured the safety and ensured about the necessity of nuclear power. However the recent disaster that took place in Fukushima has triggered public anger and distrusts that lead to negative campaigns against nuclear energy, in addition to oppositions against the government and nuclear power companies. The harsh public criticism has forced the government to separate the Nuclear and Industrial Safety Agency (NISA) from affiliation with the Ministry of Economy, Trade and Industry (METI). This action was taken since NISA had expressed contradictions with METI, which is the promoting agency for nuclear energy, The nation-wide opinion poll and surveys undertaken by Asahi Shimbun, a leading Japanese daily newspaper, has announced that 74% of respondents supported the policy to phase-out all nuclear power plants with the final goal to completely end the operation of nuclear plants. A mere 14% of the respondents disagree. There are approximately 100,000 or more residents that evacuated from the dangerous Fukushima Daiichi zone and were suffering from immediate threats such as radiation exposure, health problems, sanitary contamination, products shipment ban, business slump, groundless rumors, etc. These conditions have severely weakened their capability to completely recover and

Consequences of Fukushima 11032011 - Radiological consequences from the nuclear accidents in Fukushima on 11 March 2011

International Nuclear Information System (INIS)

2011-12-01

On 11 March 2011 at 14.46 the strongest earthquake ever recorded in Japan struck the Pacific coast in front of Fukushima. The earthquake and the following tsunami damaged the nuclear power plants in Fukushima Dai-ichi to such an extent that the Japanese government declared the state of catastrophic accident with degree 7 according to the International Nuclear and Radiological Event Scale (INES). At Fukushima Dai-ichi there were 6 boiling water reactors (BWR), a storage pool for spent fuel assemblies and a dry cask storage. 12 km apart at Fukushima Dai-ni there were 4 more BWR. At the moment of the earthquake the reactors 1 to 3 of Fukushima Dai-ichi, as well as the 4 reactors at Fukushima Dai-ni, were at full power, while the reactors 4 to 6 of Fukushima Dai-ichi were shut down for revision. From 12 March 2011 on, fairly large quantities of radioactive materials were released from Fukushima Dai-ichi reactors with meaningful consequences on the population in the near neighbourhood. The irradiation from the radioactivity bearing clouds, the ingestion and inhalation, and the deposit of radioactive materials on the ground threatened the population. The inhabitants of large areas had to be evacuated. Furthermore, radioactive materials contaminated the drinking water, the sea water and finally the plants and animals, i.e. the food chain of the people living there. The Swiss Federal Nuclear Safety Inspectorate (ENSI) continuously proceeded with the evaluation of the situation in Japan and a specialists' team made a detailed analysis of the accident, with emphasis on the human and organisational factors and on the lessons learned from this. The present report describes the present knowledge about the radiological consequences of the accident in Fukushima Dai-ichi on the population in the neighbourhood and on the staff at the power plant, until October 2011. First, the unrolling of the accident and its consequences on the plant site are analysed according to international

Current understanding of the sequence of events. Overview of current understanding of accident progression at Fukushima Dai-ichi

International Nuclear Information System (INIS)

Gulliford, Jim

2013-01-01

An overview of the main sequence of events, particularly the evolution of the cores in Units 1-3 was given. The presentation is based on information provided by Dr Okajima of JAEA to the June 2012 Nuclear Science Committee meeting. During the accident, conditions at the plant were such that operators were initially unable to obtain instruments readouts from the control panel and hence could not know what condition the reactors were in. (Reactor Power, Pressure, Temperature, Water height and flow rate, etc.). Subsequently, as electrical power supplies were gradually restored more data became available. In addition to the reactor data, other information from off-site measurements and from measuring stations inside the site boundary is now available, particularly for radiation dose rates in air. These types of information, combined with detailed knowledge of the plant design and operations history up to the time of the accident are being used to construct detailed computer models which simulate the behaviour of the reactor core, pressure vessel and containment during the accident sequence. This combination of detailed design/operating data, limited measured data during the accident and computer modelling allows us to construct a fairly clear picture of the accident progression. The main sequence of events (common to Units 1, 2 and 3) is summarised. The OECD/NEA is currently coordinating an international benchmark study of the accident at Fukushima Daiichi known as the BSAF Project. The objectives of this activity are to analyse and evaluate the accident progression and improve severe accident (SA) analysis methods and models. The project provides valuable additional (and corrected) data from plant measurements as well as an improved understanding of the role played by the fuel and cladding design. Based on (limited) plant data and extensive modelling analysis, we have a detailed qualitative description of the Fukushima-Daiichi accident. Further analyses of the type

Fukushima Daiichi Nuclear Power Plant accident: facts, environmental contamination, possible biological effects, and countermeasures

OpenAIRE

Anzai, Kazunori; Ban, Nobuhiko; Ozawa, Toshihiko; Tokonami, Shinji

2011-01-01

On March 11, 2011, an earthquake led to major problems at the Fukushima Daiichi Nuclear Power Plant. A 14-m high tsunami triggered by the earthquake disabled all AC power to Units 1, 2, and 3 of the Power Plant, and carried off fuel tanks for emergency diesel generators. Despite many efforts, cooling systems did not work and hydrogen explosions damaged the facilities, releasing a large amount of radioactive material into the environment. In this review, we describe the environmental impact of...

Accident at the Fukushima Dai-ichi Nuclear Power Stations of TEPCO —Outline & lessons learned—

OpenAIRE

TANAKA, Shun-ichi

2012-01-01

The severe accident that broke out at Fukushima Dai-ichi nuclear power stations on March 11, 2011, caused seemingly infinite damage to the daily life of residents. Serious and wide-spread contamination of the environment occurred due to radioactive materials discharged from nuclear power stations (NPSs). At the same time, many issues were highlighted concerning countermeasures to severe nuclear accidents. The accident is outlined, and lessons learned are extracted with respect to the safety o...

Examination of a measuring method for judging the influence of fallout released by the accident of the Fukushima Dai-ichi NPS

Energy Technology Data Exchange (ETDEWEB)

Onishi, Yuko; Yoshii, Taiki; Kawasaki, Satoru [Japan Nuclear Energy Safety Organization, Nulcear Fuel Cycle and Radioactive Waste Management Safety Dept., Tokyo (Japan)

2012-07-15

Radioactive nuclides were released in the atmosphere by the accident of TEPCO's Fukushima Dai-ichi Nuclear Power Station in March, 2011, and they are detected on the materials that had no artificial radioactive nuclides before the accident. Confronted with this situation, NISA issued a guideline titled 'A guideline regarding treatment of materials in nuclear facilities considering the influence of fallout released from the accident of TEPCO's Fukushima Dai-ichi Nuclear Power Station' on March 30, 2012. The guideline shows that after judging whether there is the influence of fallout or not, the conventional clearance and NR systems can be used when there is no influence of fallout. On the other hand, the special treatment is required when it is judged that there is the influence. This report describes that a specific example of measuring method of the surface contamination of the materials for the judgment of the influence of fallout. 'The precautionary measurement' defined in NR system is useful for the judgment of the influence of fallout. The criterion of the judgment is the theoretical detection limit. Sampling points for the measurement should be selected depending on expected contamination status of the survey target, considering the site area, the states of facilities or equipments and airflow from outside of the facilities. Sampling number for the fallout should be greater than equal to 10. (author)

Examination of a measuring method for judging the influence of fallout released by the accident of the Fukushima Dai-ichi NPS

International Nuclear Information System (INIS)

Onishi, Yuko; Yoshii, Taiki; Kawasaki, Satoru

2012-07-01

Radioactive nuclides were released in the atmosphere by the accident of TEPCO's Fukushima Dai-ichi Nuclear Power Station in March, 2011, and they are detected on the materials that had no artificial radioactive nuclides before the accident. Confronted with this situation, NISA issued a guideline titled 'A guideline regarding treatment of materials in nuclear facilities considering the influence of fallout released from the accident of TEPCO's Fukushima Dai-ichi Nuclear Power Station' on March 30, 2012. The guideline shows that after judging whether there is the influence of fallout or not, the conventional clearance and NR systems can be used when there is no influence of fallout. On the other hand, the special treatment is required when it is judged that there is the influence. This report describes that a specific example of measuring method of the surface contamination of the materials for the judgment of the influence of fallout. 'The precautionary measurement' defined in NR system is useful for the judgment of the influence of fallout. The criterion of the judgment is the theoretical detection limit. Sampling points for the measurement should be selected depending on expected contamination status of the survey target, considering the site area, the states of facilities or equipments and airflow from outside of the facilities. Sampling number for the fallout should be greater than equal to 10. (author)

Fukushima. A preliminary assessment in July 2011; Fukushima. Eine vorlaeufige Bilanz im Juli 2011

Energy Technology Data Exchange (ETDEWEB)

Michel, Rolf

2011-07-01

Four months after the reactor accidents in Fukushima Daiichi a preliminary assessment of the accident sequence vents is performed based on the available incomplete information. The following topics are discussed: initiating events and accident sequences, radioactive materials release and dispersion, fundamentals on radiation exposure following the accident in the nuclear power plant Fukushima Daiichi, contamination of food stuff, fission product release into the Pacific Ocean, source tern and external radiation exposure in the first year, preliminary radiological assessment, radiological situation throughout the different accident phases (radioactive cloud and fallout, late phase), estimation of radiation exposure in the first year due to decay of short-lived radionuclides based on the state end of July 2011, comparison of the reactor accidents in Chernobyl and Fukushima Daiichi.

Analysis of the accident at Fukushima Daiichi nuclear power plant in an A BWR reactor

International Nuclear Information System (INIS)

Escorcia O, D.; Salazar S, E.

2016-09-01

The present work aims to recreate the accident occurred at the Fukushima Daiichi nuclear power plant in Japan on March 11, 2011, making use of an academic simulator of forced circulation of the A BWR reactor provided by the IAEA to know the scope of this simulator. The simulator was developed and distributed by the IAEA for academic purposes and contains the characteristics and general elements of this reactor to be able to simulate transients and failures of different types, allowing also to observe the general behavior of the reactor, as well as several phenomena and present systems in the same. Is an educational tool of great value, but it does not have a scope that allows the training of plant operators. To recreate the conditions of the Fukushima accident in the simulator, we first have to know what events led to this accident, as well as the actions taken by operators and managers to reduce the consequences of this accident; and the sequence of events that occurred during the course of the accident. Differences in the nuclear power plant behavior are observed and interpreted throughout the simulation, since the Fukushima plant technology and the simulator technology are not the same, although they have several elements in common. The Fukushima plant had an event that by far exceeded the design basis, which triggered in an accident that occurred in the first place by a total loss of power supply, followed by the loss of cooling systems, causing a level too high in temperature, melting the core and damaging the containment accordingly, allowing the escape of hydrogen and radioactive material. As a result of the simulation, was determined that the scope of the IAEA academic simulator reaches the entrance of the emergency equipment, so is able to simulate almost all the events occurred at the time of the earthquake and the arrival of the tsunami in the nuclear power plant of Fukushima Daiichi. However, due to its characteristics, is not able to simulate later

What next for Fukushima?

Science.gov (United States)

Drinkwater, Bruce; Malkin, Rob

2018-01-01

Nearly seven years after a powerful tsunami caused catastrophic damage to Japan's Fukushima Daiichi nuclear-power plant, the clean-up and recovery is still ongoing. Bruce Drinkwater and Rob Malkin recently visited the disaster site and the undamaged Tsuruga plant to see if they can pinpoint the true extent of the damage in the dangerously radioactive reactors

Update on the SDTP Sponsored Fukushima Daiichi Related Assesment Activities

International Nuclear Information System (INIS)

Allison, Chris

2014-01-01

Following the accident at Fukushima Daiichi, Innovative Systems Software and several other members of an international software development and training group (SDTP) started an assessment of the possible core/vessel damage states of Units 1-3. This assessment, using a reference RELAP/SCDAPSIM Laguna Verde BWR model developed by CNSNS, the Mexican nuclear regulatory body, was presented initially to the IAEA emergency response team for Fukushima in March of 2011. Our assessment for the IAEA indicated that significant fuel melting, fuel slumping, and lower head failure was likely for Units 1 and 3. The results for Unit 2 were inconclusive because of the complex thermal hydraulic conditions at the time of likely fuel melting. Since that time the SDTP related assessment activities have continued on three main fronts: (a) continued analysis using our representative Laguna Verde model to determine the likely failure modes leading to an un-intentional depressurization of the vessel during a SBO in a BWR, (b) development of improved RELAP/SCDAPSIM models to treat the likely mode of lower core support structure melting and failure, and (c) design studies for proposed fuel melting and relocation experiments in Japan to support model development and cleanup related activities, The presentation gives a brief summary and discussion of these activities.

New Standards in Liquid Waste Treatment at Fukushima Dai-ichi - 13134

Energy Technology Data Exchange (ETDEWEB)

Sylvester, Paul; Milner, Tim; Ruffing, Jennifer; Poole, Scott [EnergySolutions, 100 Center Point Circle, Suite 100, Center Point II, Columbia, SC 29210 (United States); Townson, Paul; Jensen, Jesse [EnergySolutions, 2345 Stevens Drive, Suite 240, Richland, WA 99354 (United States)

2013-07-01

The earthquake and tsunami on March 11, 2011 severely damaged the Fukushima Dai-ichi nuclear plant leading to the most severe nuclear incident since Chernobyl. Ongoing operations to cool the damaged reactors at the site have led to the generation of highly radioactive coolant water. This is currently mainly treated to remove Cs-137 and Cs-134 and passed through a reverse osmosis (RO) unit to reduce the salinity before being cycled back to the reactors. Because only the Cs isotopes are removed, the RO reject water still contains many radioactive isotopes and this has led to the accumulation of over 200,000 cubic meters (52 million gallons) of extremely contaminated water which is currently stored on site in tanks. EnergySolutions, in partnership with Toshiba, were contracted to develop a system to reduce 62 isotopes in this waste down to allowable levels. This was a significant technical challenge given the high background salt content of the wastewater, the variation in aqueous chemistry of the radioactive isotopes and the presence of non-active competing ions (e.g. Ca and Mg) which inhibit the removal of isotopes such as Sr-89 and Sr-90. Extensive testing was performed to design a suitable system that could meet the required decontamination goals. These tests were performed over a 6 month period at facilities available in the nearby Fukushima Dai-ni laboratory using actual waste samples. This data was then utilized to design a Multi Radioactive Nuclides Removal System (MRRS) for Fukushima which is a modified version of EnergySolutions' proprietary Advanced Liquid Processing System (ALPS)'. The stored tank waste is fed into a preliminary precipitation system where iron flocculation is performed to remove a number of isotopes, including Sb-125, Ru-106, Mn-54 and Co-60. The supernatant is then fed into a second precipitation tank where the pH is adjusted and the bulk of the Mg, Ca and Sr precipitated out as carbonates and hydroxides. After passing through a

Remediation activities wrestling with environmental pollution and radwaste generated by the Fukushima Daiichi NPP accident due to the Tohoku district-off the pacific ocean

International Nuclear Information System (INIS)

Kawanishi, Motoi; Fujitsuka, Tetsuro; Yoshihara, Koichi; Katsumi, Takeshi; Tochiyama, Osamu

2013-01-01

Based on the lectures and panel discussions 'Radioactive waste countermeasures and the role of civil engineering technology' on the occasion of 3rd year of the Great East Japan Earthquake, March 11, 2011, hosted by the Japan Society of Civil Engineers, the paper summarizes remediation activities reported during the seminar. Radioactive materials contaminated area due to the Fukushima Daiichi Nuclear Power Plant accident from the Department of Environment, endeavors for setting-up of temporary storage facilities for the decontaminated soils and solid wastes, present status of roadmap toward the decommissioning of the Fukushima Daiichi Plants from the Japanese Government and Tokyo Electric Power Co. were presented followed by expectations of civil engineers cooperation. (S. Ohno)

Environmental remediation following the Fukushima-Daiichi accident

Energy Technology Data Exchange (ETDEWEB)

Tagawa, A.; Miyahara, K.; Nakayama, S. [Japan Atomic Energy Agency - JAEA, 4-49 Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1184 (Japan)

2013-07-01

A wide area of Fukushima Prefecture was contaminated with radioactivity released by the Fukushima Daiichi nuclear accident. The decontamination pilot projects conducted by JAEA aimed at demonstrating the applicability of different techniques to rehabilitate affected areas. As most radioactive cesium is concentrated at the top of the soil column and strongly bound to mineral surfaces, there are 3 options left to decrease the gamma dose rate (usually measured 1 m above the ground surface): the stripping of the contaminated topsoil (i.e. direct removal of cesium), the dilution by mixing and the soil profile inversion. The last two options do not generate waste. As the half-distance of {sup 137}Cs gammas in soil is in the order of 5-6 cm (depending on density and water content), the shielding by 50 cm of uncontaminated deep soil would theoretically reduce gamma doses by about 3 orders of magnitude. Which option is employed depends basically on the Cesium concentration in the topsoil, averaged over a 15-cm thickness. The JAEA's decontamination pilot projects focus on soil profile inversion and topsoil stripping. Two different techniques have been tested for the soil profile inversion: one is the reversal tillage by which surface soil of thickness of several tens of cm is reversed by using a tractor plough and the other is the complete interchanging of contaminated topsoil with uncontaminated subsoil by using a back-hoe. Reversal tillage with a tractor plough cost about 30 yen/m{sup 2}, which is an order of magnitude lower than that of topsoil-subsoil interchange (about 300 yen/m{sup 2}). Topsoil stripping is significantly more costly (between 550 yen/m{sup 2} and 690 yen/m{sup 2} according to the equipment used)

Public opinion on Fukushima Daiichi nuclear disaster

International Nuclear Information System (INIS)

Hirose, Hirotada

2013-01-01

This article showed trend of public opinion on nuclear power after Fukushima Daiichi nuclear disaster, for which the survey had been done five times under the same method and inquiries. Most unreliable source of information at disaster was government ministries and offices, whose unreliability sharply increased from 20% to about 50% after 3 months later and one year later after March 11 and reliability after 2 year and 5 months later (August 2013) was not high and almost comparable with unreliability of 27%. Nuclear disaster was most serious cause of Great East Japan earthquake disaster (60%) and not entirely ended due to such increase of contaminated water. Public opinion survey in August 2013 showed nuclear power stoppage totaled about 80% with immediate of about 30% and phaseout of about 50%, and possibility of occurrence of another nuclear accident comparable with Fukushima disaster was almost 80% with a belief not only earthquakes, tsunamis, terrorism but also human errors might initiate nuclear disaster if nuclear power restarted. Future most serious disaster would be earthquake (50%) and nuclear disaster (35%). Nuclear accident preparedness of government and local government was not enough (58% and 24%) and nothing (33% and 24%). Residents within UPZ (Urgent Protection action Planning Zone) of 30 km radius could not evacuate safely (57%) and entirely (22%). If government and local government encouraged damaged residents to come home with declaration of safety for evacuation area of nuclear accident, damaged residents might not return almost (46%) and entirely (9%). Notwithstanding people's strong feeling against nuclear power, LDP (Liberal Democratic Party) promoting nuclear power won an overwhelming victory at the election of House of Councilors in July 2013. Public opinion survey in August 2013 showed most important issue of voters was party's image (25%), economic measures (20%) and candidate's personality (13%), and nuclear power policy was only 5%. (T

The Fukushima Daiichi Accident. Technical Volume 2/5. Safety Assessment

International Nuclear Information System (INIS)

2015-08-01

Technical Volume 1 of this report has described what happened during the accident at the Fukushima Daiichi nuclear power plant (NPP). This volume begins (Section 2.1) with a review of how the design basis of the site for external events was assessed initially and then reassessed over the life of the NPP. The section also describes the physical changes that were made to the units as a result. The remainder of the volume describes the treatment of beyond design basis events in the safety assessment of the site, the accident management provisions, the effectiveness of regulatory programmes, human and organizational factors and the safety culture, and the role of operating experience. Further background information is contained in three annexes included on the CD-ROM of this Technical Volume which describe analytical investigations of the accident along with information on topics such as system performance, defence in depth and severe accident phenomena. Section 2.2 provides an assessment of the systems that failed, resulting in a failure to maintain the fundamental safety functions in Units 1–3, which were in operation at the time of the tsunami and in which the reactor pressure vessels (RPV) and containment vessels failed. The section also describes Units 4-6, which were shut down at the time of the tsunami, and the site’s central spent fuel storage facility. Section 2.3 discusses the probabilistic and deterministic safety assessments of beyond design basis accidents (BDBAs) that had been performed for the plant and the insights from these assessments that had led to changes in the plant’s design. The section pays particular attention to the assessment of extreme natural hazards, such as the one which led to the total loss of AC power supply on the site. The additional loss of DC power supply in Units 1 and 2 played a key role in the progression of the accident because it impeded the diagnosis of plant conditions and made the operators unaware of the status of

US Efforts in Support of Examinations at Fukushima Daiichi – 2016 Evaluations

Energy Technology Data Exchange (ETDEWEB)

Amway, P. [Exelon Corp., Chicago, IL (United States); Andrews, N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bixby, Willis [WWBX Consulting, Crofton, MD (United States); Bunt, R. [Southern Nuclear. Birmingham, AL (United States); Corradini, M. [Univ. of Wisconsin, Madison, WI (United States); Ellison, P. [GE-Hitachi, Wilmington, NC (United States); Farmer, M. [Argonne National Lab. (ANL), Argonne, IL (United States); Farthing, T. [GE-Hitachi, Wilmington, NC (United States); Francis, M [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gabor, J. [Jensen Hughes, Baltimore, MD (United States); Gauntt, R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Henry, C. [Fauske and Associates, LLC, Burr Ridge, IL (United States); Humrickhouse, P. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kraft, S. [Nuclear Energy Inst., Washington, DC (United States); Linthicum, R. [Exelon Corp., Chicago, IL (United States); PWR Owners Group; Luangdilok, W. [Fauske and Associates, LLC, Burr Ridge, IL (United States); Lutz, R. [Lutz Nuclear Consulting, Asheville, NC (United States); Luxat, D. [Jensen Hughes, Baltimore, MD (United States); Maddox, J. [Inst. for Nuclear Power Operations, Atlanta, GA (United States); Negin, C. [CANegin & Associates; Paik, C. [Fauske and Associates, LLC, Burr Ridge, IL (United States); Plys, M. [Fauske and Associates, LLC, Burr Ridge, IL (United States); Rempe, J. [Rempe and Associates, Idaho Falls, ID (United States); Robb, K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sanders, R. [AREVA Federal Services, Charlotte, NC (United States); Wachowiak, R. [Electric Power Research Inst. (EPRI), Palo Alto, CA (United States); Williamson, B. [Tennessee Valley Authority, Knoxville, TN (United States)

2016-08-01

Although it is clear that the accident signatures from each unit at the Fukushima Daiichi Nuclear Power Station (NPS) [Daiichi] differ, much is not known about the end-state of core materials within these units. Some of this uncertainty can be attributed to a lack of information related to cooling system operation and cooling water injection. There is also uncertainty in our understanding of phenomena affecting: a) in-vessel core damage progression during severe accidents in boiling water reactors (BWRs), and b) accident progression after vessel failure (ex-vessel progression) for BWRs and Pressurized Water Reactors (PWRs). These uncertainties arise due to limited full scale prototypic data. Similar to what occurred after the accident at Three Mile Island Unit 2, these Daiichi units offer the international community a means to reduce such uncertainties by obtaining prototypic data from multiple full-scale BWR severe accidents. Information obtained from Daiichi is required to inform Decontamination and Decommissioning activities, improving the ability of the Tokyo Electric Power Company Holdings (TEPCO) to characterize potential hazards and to ensure the safety of workers involved with cleanup activities. This document reports recent results from the US Forensics Effort to use information obtained by TEPCO to enhance the safety of existing and future nuclear power plant designs. This Forensics Effort, which is sponsored by the Reactor Safety Technologies Pathway of the Department of Energy Office of Nuclear Energy Light Water Reactor (LWR) Sustainability Program, consists of a group of US experts in LWR safety and plant operations that have identified examination needs and are evaluating TEPCO information from Daiichi that address these needs. Examples presented in this report demonstrate that significant safety insights are being obtained in the areas of component performance, fission product release and transport, debris end-state location, and combustible gas

Current status and problems of decontamination by municipalities in Fukushima Prefecture. Records from four and a half years after the Fukushima Daiichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Kawasaki, Kota

2016-01-01

This study discusses the current status and problems of decontamination by 52 municipalities out of 59 municipalities in Fukushima Prefecture, four and a half years after the Fukushima Daiichi Nuclear Power Plant accident, mainly based on the results of a questionnaire survey. The area corresponds to in all municipalities except for the 7 whose entire administrative area has been designated as Special Decontamination Area. This study reveals that (1) the number of municipalities which planned, ordered and implemented decontamination work has peaked although decontamination work of public facilities, housing, roads, farmland and forests has been still carried out in many municipalities, (2) about half of the municipalities have not secured enough temporary storage sites for contaminated soil and waste, (3) many municipalities recognize that construction of interim storage facilities, transfer of contaminated soil and waste from each municipality to interim storage facilities, and maintenance of temporary storage sites are major challenges concerning decontamination work, (4) about half of the municipalities regard efforts concerning decontamination work by the national government and the Fukushima prefectural government office as inadequate, (5) not a few municipalities recognize that residents cannot live their lives with a sense of safety and security unless air radiation dose is reduced to the level before the accident, and (6) most municipalities recognize that safe living environments can be recovered by decontamination work. Finally, based on these results, this study points out early completion of interim storage facilities and development of conditions to maintain and manage temporary storage sites, the end of decontamination work based on the air radiation dose rate, and establishment of decontamination policies concerning forests, rivers and waterways, as main future challenges concerning decontamination work by municipalities. (author)

Monitoring of Radionuclide Contamination in Food Samples in Malaysia due to Daiichi Reactor Accident in Fukushima, Japan

International Nuclear Information System (INIS)

Nurrul Assyikeen Mohd Jaffary; Wo, Y.M.; Abdul Kadir Ishak

2015-01-01

On March 11, 2011, a serious accident occurred in Daiichi nuclear reactor plant, Fukushima, Japan which caused radioactive materials been released into the atmosphere in the form of aerosols and dust particles. Sea water around the plant was also found contaminated with high radioactivity readings. These radioactive materials could be transported by the winds and ocean current across international borders and cannot be controlled by human. Thus, a continuous monitoring activity of radionuclide content in the air and sea water needs to be conducted by the authorities. In addition to radioactivity monitoring, Malaysia should also control the entry of contaminated food in order to prevent radionuclide ingestion by human. The radionuclide 131 I, 134 Cs and 137 Cs were used as a measure of pollution levels and counted with gamma spectrometry using standard analysis method suggested by AOAC International. In this paper, details description of the role of Radiochemical and Environment Group, Nuclear Malaysia who is responsible in analyzing the radioactivity in the food samples due to Fukushima Daiichi, Japan accident was included. The radioactivity limit adopted and analysis results from this monitoring were discussed. (author)

Damage of reactor buildings occurred at the Fukushima Daiichi accident. Focusing on sequence leading to hydrogen explosions

International Nuclear Information System (INIS)

Naito, Masanori

2011-01-01

Fukushima Daiichi accident discharged enormous radioactive materials confined inside into the environment due to hydrogen explosions occurred at reactor buildings and forced many people to live the refugee life. This article described overview of Great East Japan Earthquake, specifications of Fukushima Daiichi nuclear power plants, sequence of plant status after earthquake occurrence and computerized simulation of plant behavior of Unit 1 leading to core melt and hydrogen explosion. Simulation results with estimated and assumed conditions showed water level decreased to bottom of reactor core after 4 hrs and 15 minutes passed, core melt started after 6 hrs and 49 minutes passed, failure of core support plate after 7 hrs and 18 minutes passed and through failure of penetration at bottom of pressure vessel after 7 hrs and 25 minutes passed. Hydrogen concentration at operating floor of reactor building of Unit 1 would be 15% accumulated and the pressure would amount to about 5 bars after hydrogen explosion if reactor building did not rupture with leak-tight structure. Since reactor building was not pressure-proof structure, walls of operating floor would rupture before 5 bars attained. (T. Tanaka)

TEPCO's risk communication activities in Fukushima Prefecture in light of the lessons learned from the Fukushima Daiichi Nuclear Power Station accident

International Nuclear Information System (INIS)

Sagasaki, Yoshitoyo; Yamamoto, Takashi

2015-01-01

This paper introduces the risk communication activities of the Tokyo Electric Power Company (TEPCO) in Fukushima Prefecture. It analyzed the organizational cause as the background for the Fukushima Daiichi Nuclear Power Station Accident, and concluded that the root cause of the accident is the thought that 'safety has already been secured, and operation rate and the like are important management issues, which incurred the insufficient preparedness for accident.' It has taken six measures as nuclear safety reform plans. One of these is the 'enhancement of risk communication activities.' The nuclear power leader take the initiative to disclose risk under the idea that 'there is no absolute safety (zero risk) in nuclear power,' and promote risk communication for continuously obtaining the understanding of the regional community and society about safety measures, etc. To implement risk communication, 'risk communicators' are installed, and they propose for the management and nuclear leader, about the risk perception and measures associated with public disclosure and its limit, and perform risk communication in accordance with the policy. As the examples of these initiatives, this paper introduces the cases of Fukushima Prefecture, questionnaire study, and evaluations by international organizations. (A.O.)

Dose estimation from food intake due to the Fukushima Daiichi nuclear power plant accident

International Nuclear Information System (INIS)

Yamaguchi, Ichiro; Terada, Hiroshi; Kunugita, Naoki; Takahashi, Kunihiko

2013-01-01

Since the Fukushima Daiichi nuclear power plant accident, concerns have arisen about the radiation safety of food raised at home and abroad. Therefore, many measures have been taken to address this. To evaluate the effectiveness of these measures, dose estimation due to food consumption has been attempted by various methods. In this paper, we show the results of dose estimation based on the monitoring data of radioactive materials in food published by the Ministry of Health, Labour and Welfare. The Radioactive Material Response Working Group in the Food Sanitation Subcommittee of the Pharmaceutical Affairs and Food Sanitation Council reported such dose estimation results on October 31, 2011 using monitoring data from immediately after the accident through September, 2011. Our results presented in this paper were the effective dose and thyroid equivalent dose integrated up to December 2012 from immediately after the accident. The estimated results of committed effective dose by age group derived from the radioiodine and radiocesium in food after the Fukushima Daiichi nuclear power plant accident showed the highest median value (0.19 mSv) in children 13-18 years of age. The highest 95% tile value, 0.33 mSv, was shown in the 1-6 years age range. These dose estimations from food can be useful for evaluation of radiation risk for individuals or populations and for radiation protection measures. It would also be helpful for the study of risk management of food in the future. (author)

Radiological protection and the Fukushima Daiichi accident. Responses of the key international organisations

Energy Technology Data Exchange (ETDEWEB)

Clement, Christopher

2017-10-01

The Fukushima Daiichi nuclear power plant accident in March 2011 shook the radiological protection world. All major organisations in the radiological protection field turned their eyes to Japan. Their actions, driven by their mandates, are reflected in their respective landmark reports on the accident. Reports of the International Commission on Radiological Protection, World Health Organisation, United Nations Scientific Committee on the Effects of Atomic Radiation, and International Atomic Energy Agency are summarised. Collaboration between key international organisations is strong, based in part on informal interactions which need to be backed up with formal relations to ensure solid long-term collaboration.

Research on vitrification technology to immobilize radioactive sludge generated from Fukushima Daiichi power plant. Enhanced glass medium

International Nuclear Information System (INIS)

Amamoto, Ippei; Kobayashi, Hidekazu; Kitamura, Naoto; Takebe, Hiromichi; Mitamura, Naoki; Tsuzuki, Tatsuya; Fukayama, Daigen; Nagano, Yuichi; Jantzen, Tatjana; Hack, Klaus

2016-01-01

The search for an enhanced glass medium to immobilize the sludge at the Fukushima Daiichi Nuclear Power Plant is our main purpose. The iron phosphate glass (IPG) is a potential candidate as we set about assessing it by means of theoretical and experimental investigation. Based on the results of this study, the IPG showed favorable characteristics as a vitrification medium for the sludge. (author)

The cross-section of returns, benchmark model parameters, and idiosyncratic volatility of nuclear energy firms after Fukushima Daiichi

International Nuclear Information System (INIS)

Lopatta, Kerstin; Kaspereit, Thomas

2014-01-01

This study analyzes how the stock market returns, the factor loadings from the Carhart (1997) 4-factor model, and the idiosyncratic volatility of shares in energy firms have been affected by the Fukushima nuclear accident. Unlike existing studies, which provide evidence of a wealth transfer from nuclear to renewable energy firms for specific countries, we use an international sample and investigate whether changes in the regulatory environment and the firm-specific commitment to nuclear and renewable energies correlate with the capital market's reactions to the Fukushima Daiichi accident. Our findings suggest that the more a firm relies on nuclear power, the more its share price declined after the accident. A commitment to renewable energies does not prevent declines in share prices but significantly helps to reduce the increase in market beta that is associated with this event. Nuclear energy firms domiciled in countries with a higher number of regulatory interventions that were triggered by the catastrophe have lower abnormal returns than those that are domiciled elsewhere. However, as a cross-sectional analysis reveals, a stronger commitment to nuclear power is the main driver for negative stock market returns. Furthermore, nuclear energy firms domiciled in countries with stronger regulatory shifts away from nuclear energy experience significant increases in market beta and the book-to-market equity factor loading according to the Carhart (1997) 4-factor model. We conclude that capital market participants are able to differentiate between the affectedness of firms with respect to their product portfolio. Energy firms could prevent increases in market beta due to catastrophes such as the Fukushima Daiichi accident by shifting some of their energy production from nuclear to renewable or other sources. - Highlights: • Abnormal stock returns of nuclear energy firms around Fukushima Daiichi depend on the mix of their energy portfolio. • Higher commitment to

The Fukushima Daiichi Nuclear Power Plant accident and school bullying of affected children and adolescents: the need for continuous radiation education.

Science.gov (United States)

Sawano, Toyoaki; Nishikawa, Yoshitaka; Ozaki, Akihiko; Leppold, Claire; Tsubokura, Masaharu

2018-04-09

The health threats of radiation-release incidents are diverse and long term. In addition to direct radiation effects, it is imperative to manage the indirect effects of radiation such as stigma, prejudice and broader mental health impacts. Six years after the Fukushima Daiichi Nuclear Power Plant accident of March 2011, bullying caused by stigma and prejudice toward evacuees, including children, has become a social problem in Japan. This phenomenon may be associated with the fact that knowledge about radiation has still not reached the general public, and to a potential lack of motivation among Japanese citizens to learn about radiation and bullying. Continuous and sustained education regarding radiation is warranted in order to enhance the general knowledge level about the effects of radiation in Japan after the Fukushima Daiichi Nuclear Power Plant accident, and this education will become an important reference for education after future nuclear disasters.

Research and Activities of OECD/NEA Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Station (BSAF) Project

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Il; Ha, Kwang Soon; Song, JinHo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

The severe accident codes were used to analysis the Fukushima Daiichi accident and give valuable information. In addition, the insufficient part of the code could be revised by comparing the calculation result with the measured data. In this circumstance, working plans have been set up to conduct a Benchmark Study of the Accident progression for the Fukushima Daiichi nuclear power plant(BSAF) units 1-3 with the members of the OECD/NEA. The BSAF project was launched in November 2012 with the fifteen organizations of eight countries (France, Germany, Korea, Russia, Spain, Switzerland, the United States, and Japan). The objectives of the project are: - to analyze the Fukushima accident progression. - to raise the understanding of severe accident(SA) phenomena. - to contribute the improvement of methods and models of SA code. - to contribute the status of debris distribution to a future debris removal plan. BSAF phase 2 also has been implemented from April, 2015 and it will be continued to March, 2018. It is more focused on the fission product behavior and source term estimation in phase 2. The phase 2 project implementation period is 3 years from April 2015 to March 2018. The main topic of the BSAF 2 is the fission product behavior in the Fukushima nuclear power plant. In the process of calculation, it is important to know the insufficient models in the code. Furthermore, the model would be applied to the KAERI's severe accident code after making up for the insufficient part.

Dose rate evaluation of workers on the operation floor in Fukushima-Daiichi Unit 3

Science.gov (United States)

Matsushita, Kaoru; Kurosawa, Masahiko; Shirai, Keisuke; Matsuoka, Ippei; Mukaida, Naoki

2017-09-01

At Fukushima Daiichi Nuclear Power Plant Unit 3, installation of a fuel handling machine is planned to support the removal of spent fuel. The dose rates at the workplace were calculated based on the source distribution measured using a collimator in order to confirm that the dose rates on the operation floor were within a manageable range. It was confirmed that the accuracy of the source distribution was C/M = 1.0-2.4. These dose rates were then used to plan the work on the operation floor.

Fukushima Daiichi unit 1 uncertainty analysis--Preliminary selection of uncertain parameters and analysis methodology

Energy Technology Data Exchange (ETDEWEB)

Cardoni, Jeffrey N.; Kalinich, Donald A.

2014-02-01

Sandia National Laboratories (SNL) plans to conduct uncertainty analyses (UA) on the Fukushima Daiichi unit (1F1) plant with the MELCOR code. The model to be used was developed for a previous accident reconstruction investigation jointly sponsored by the US Department of Energy (DOE) and Nuclear Regulatory Commission (NRC). However, that study only examined a handful of various model inputs and boundary conditions, and the predictions yielded only fair agreement with plant data and current release estimates. The goal of this uncertainty study is to perform a focused evaluation of uncertainty in core melt progression behavior and its effect on key figures-of-merit (e.g., hydrogen production, vessel lower head failure, etc.). In preparation for the SNL Fukushima UA work, a scoping study has been completed to identify important core melt progression parameters for the uncertainty analysis. The study also lays out a preliminary UA methodology.

Accident on the TEPCO reactors of Fukushima-Daiichi. A focus on the situation in January 2013

International Nuclear Information System (INIS)

2013-01-01

After a brief recall of the accident of the Fukushima-Daiichi nuclear power station and a brief description of the general condition of the installations after the accident, this report proposes an overview of actions performed by TEPCO to control the installations, the actions performed to control effluents and releases. It presents the action plan for the control's recovery of installations, and briefly evokes the situation for other electronuclear reactors in Japan

Radiocesium concentrations in the bark, sapwood and heartwood of three tree species collected at Fukushima forests half a year after the Fukushima Dai-ichi nuclear accident.

Science.gov (United States)

Kuroda, Katsushi; Kagawa, Akira; Tonosaki, Mario

2013-08-01

Radiocesium ((134)Cs and (137)Cs) distribution in tree stems of Japanese cedar (aged 40-56 y), red pine (42 y), and oak (42 y) grown in Fukushima Prefecture were investigated approximately half a year after the Fukushima Dai-ichi nuclear accident. Japanese cedar, red pine, and oak were selected from five sites, one site, and one site, respectively. Three trees at each site were felled, and bark, sapwood (the outer layer of wood in the stem), and heartwood (the inner layer of wood in the stem) separately collected to study radiocesium concentrations measured by gamma-ray spectrometry. The radiocesium deposition densities at the five sites were within the range of 16-1020 kBq m(-2). The radiocesium was distributed in bark, sapwood, and heartwood in three tree species, indicating that very rapid translocation of radiocesium into the wood. The concentration of radiocesium in oak (deciduous angiosperm) bark was higher than that in the bark of Japanese cedar and red pine (evergreen gymnosperms). Both sapwood and heartwood contained radiocesium, and the values were much lower than that in the bark samples. The results suggest that radiocesium contamination half a year after the accident was mainly attributable to the direct radioactive deposition. The radiocesium concentrations in the Japanese cedar samples taken from five sites rose with the density of radiocesium accumulation on the ground surface. To predict the future dynamics of radiocesium in tree stems, the present results taken half a year after the accident are important, and continuous study of radiocesium in tree stems is necessary. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development of source term PIRT of Fukushima Daiichi NPPs accident

International Nuclear Information System (INIS)

Suehiro, S.; Okamoto, K.

2017-01-01

The severe accident evaluation committee of AESJ (Atomic Energy Society of Japan) developed the thermal hydraulic PIRT (Phenomena Identification and Ranking Table) and the source term PIRT based on findings during the Fukushima Daiichi NPPs accident. These PIRTs aimed to explore the debris distribution and the current condition in the NPPs with high accuracy and to extract higher priority from the aspect of the sophistication of the analytical technology to predict the severe accident phenomena by the code. The source term PIRT was divided into 3 phases for the time domain and 9 categories for the spatial domain. The 68 phenomena were extracted and the importance from viewpoint of the source term was ranked through brainstorming and discussion. This paper describes the developed source term PIRT list and summarized the high ranked phenomena in each phase. (author)

Re-suspension of Cesium-134/137 into the Canadian Environment and the Contribution Stemming from the Fukushima-Daiichi Nuclear Incident

Science.gov (United States)

Mercier, Jean-Francois; Zhang, Weihua; Loignon-Houle, Francis; Cooke, Michael W.; Ungar, Kurt R.; Pellerin, Eric R.

2013-04-01

Cesium-137 (t1/2 = 30 yr) and cesium-134 (t1/2 = 2yr) constitute major fission by-products observed as the result of a nuclear incident. Such radioisotopes become integrated into the soil and biomass, and can therefore undergo re-suspension into the environment via activities such as forest fires. The Canadian Radiological Monitoring Network (CRMN), which consists of 26 environmental monitoring stations spread across the country, commonly observes cesium-137 in air filters due to re-suspension of material originating from long-past weapons testing. Cesium-134 is not observed owing to its relatively short half-life. The Fukushima-Daiichi nuclear power plant incident of March 2011 caused a major release of radioactive materials into the environment. In Canada, small quantities of both cesium-137 and cesium-134 fallout were detected with great frequency in the weeks which followed, falling off rapidly beginning in July 2011. Since September 2011, the CRMN has detected both cesium-137 and cesium-134 from air filters collected at Yellowknife, Resolute, and Quebec City locations. Using the known initial cesium-134/cesium-137 ratio stemming from this incident, along with a statistical assessment of the normality of the data distribution, we herein present evidence that strongly suggests that these activity spikes are due to re-suspended hot particles originating from the Fukushima-Daiichi nuclear power plant incident. Moreover, we have evidence to suggest that this re-suspension is localized in nature. This study provided empirical insight into the transport and uptake of radionuclides over vast distances, and it demonstrates that the CRMN was able to detect evidence of a re-suspension of Fukushima-Daiichi related isotopes.

New public commons and network of nuclear site regions for the post-Fukushima accident re-vitalization

International Nuclear Information System (INIS)

Sawada, Tetsuo

2011-01-01

Due to the Fukushima Daiichi NPP accidents on March 11 2011, the landscape of the community of nuclear energy R and D and usage has been changing in various aspects here in Japan. With such recognition, the networking of nuclear site regions as well as consumer cities is proposed for obtaining novel-sense societal confidence, on the basis of on-going practice of atom-sports such as international MaxiMarathon and domestoic Tour de Atom. (author)

Exploiting Bulgarian emergency response system for simulation of Fukushima nuclear accident

Energy Technology Data Exchange (ETDEWEB)

Syrakov, D.; Prodanova, M. [National Institute of Meteorology and Hydrology, Bulgarian Academy of Sciences, Sofia (Bulgaria)

2012-07-01

The severe accident in Fukushima Nuclear Power Plant (NPP) in 2011 causes serious anxiety among the population not only in the neighbourhood, but even in countries quite far from the accident location. On Friday, March 11, 2011, Japan experienced a natural disaster of inconceivable dimensions. At 2.46p.m. local time, a gigantic earthquake with the epicentre approx. 150 km east of the city of Sendai in the Pacific Ocean also shook the coastal region nearby. The seismic event was triggered by abrupt tectonic plate shifts some 20 to 30 km below sea level. The seaquake had an intensity of 9.0 on the logarithmic scale, which is O.S points above the severest earthquake of 8.2 so far registered in Japan. This unexpectedly high energy release caused a tsunami wave of a maximum height of 23 m which flooded the coastal region approximately one hour later, causing a large number of human casualties and extreme devastation of towns and villages, infrastructure, and the environment. Four nuclear power plants are located in the area directly affected by the disaster: Onagawa, Fukushima Daiichi, Fukushima Daini, and Toman. The site of Fukushima Daiichi was hit most severely. Bulgarian ERS (BERSJ was upgraded to be able to simulate the dispersion of nuclear materials from Fukushima Daiichi NPP, results presented in the specialised web-site of the system. In addition BERS took part in the respective ENSEMBLE exercises. Short BERS description as well as its results and comparisons with measurements and other model results are the object of this work. (author)

Exploiting Bulgarian emergency response system for simulation of Fukushima nuclear accident

International Nuclear Information System (INIS)

Syrakov, D.; Prodanova, M.

2012-01-01

The severe accident in Fukushima Nuclear Power Plant (NPP) in 2011 causes serious anxiety among the population not only in the neighbourhood, but even in countries quite far from the accident location. On Friday, March 11, 2011, Japan experienced a natural disaster of inconceivable dimensions. At 2.46p.m. local time, a gigantic earthquake with the epicentre approx. 150 km east of the city of Sendai in the Pacific Ocean also shook the coastal region nearby. The seismic event was triggered by abrupt tectonic plate shifts some 20 to 30 km below sea level. The seaquake had an intensity of 9.0 on the logarithmic scale, which is O.S points above the severest earthquake of 8.2 so far registered in Japan. This unexpectedly high energy release caused a tsunami wave of a maximum height of 23 m which flooded the coastal region approximately one hour later, causing a large number of human casualties and extreme devastation of towns and villages, infrastructure, and the environment. Four nuclear power plants are located in the area directly affected by the disaster: Onagawa, Fukushima Daiichi, Fukushima Daini, and Toman. The site of Fukushima Daiichi was hit most severely. Bulgarian ERS (BERSJ was upgraded to be able to simulate the dispersion of nuclear materials from Fukushima Daiichi NPP, results presented in the specialised web-site of the system. In addition BERS took part in the respective ENSEMBLE exercises. Short BERS description as well as its results and comparisons with measurements and other model results are the object of this work. (author)

Problems of probabilistic safety assessment after Fukushima Daiichi nuclear power plant accident

International Nuclear Information System (INIS)

Sugiyama, Naoki

2011-01-01

Probabilistic safety assessment (PSA) methodology to assure nuclear safety is had great expectations of lessons learned from Fukushima Daiichi nuclear power plant (NPP) accident and on the other hand this accident made actualized technical problems of PSA. Effectiveness of current PSA methodology for risk assessment was confirmed by comparing the accident development with accident scenario of PSA and equipment failure rate. From a viewpoint of nuclear safety objective and defense in depth approach of IAEA, technical problems of PSA were (1) extension of PSA for spent fuel pool and waste disposal system as well as level 3PSA for broader environmental contamination and (2) overlapping of accident scenario of plural unit site, balance of high quality plant management and preceding negation, treatment of uncertainty of external events, severe accident measure and human reliability analysis and reflection of disaster prevention capability to level 3PSA. In order to upgrade PSA technology, six proposals were described for nuclear safety and defense in depth, comprehensive evaluation scope and catch-up of latest technology, necessity of strategic preparation of PSA standard, human resources fostering and risk communication. (T. Tanaka)

Activities of radionuclides in the Pacific coastal area of Fukushima since the TEPCO Fukushima Daiichi Nuclear Power Station accident - Activities of radionuclides in the coast area off Fukushima after TEPCO's Fukushima Daiichi Nuclear Power Station accident

Energy Technology Data Exchange (ETDEWEB)

Aono, Tatsuo; Fukuda, Miho; Yoshida, Satoshi [National Institute of Radiological Sciences, 263-8555, Chiba (Japan); Sohtome, Tadahiro; Mizuno, Takuji [Fukushima Prefecture Fisheries Experimental Station, 970-0316, Fukushima (Japan); Igarashi, Satoshi [Fukushima Prefecture Fisheries Experimental Station, 970-0316, Fukushima (Japan); Fukushima Prefecture Sea-Farming Association, 970-8044, Fukushima (Japan); Ito, Yukari; Kanda, Jota; Ishimaru, Takashi [Tokyo University of Marine Science and Technology, 108-0075, Tokyo (Japan)

2014-07-01

The accident of TEPCO's Fukushima Daiichi Nuclear Power Station (FDNPS) has caused the release of the huge quantities of radionuclide by the 2011 Great East Japan Earthquake and Tsunami, and then the serious problems gave rise to pollution in marine environment widely in the coast area off Fukushima. Monitoring of radioactivity in seawater and biota are important for understanding the dispersion of radionuclides and the effects of radioecology in the marine environment around the coast of Fukushima and the Pacific. The activities of Cs-134 and Cs-137 in seawater decreased exponentially and then were almost same levels before the accident around off Fukushima after about three years from the accident. However, the high activities of radio caesium (Cs) have been monitored in marine biota off Fukushima. The aims of the present study were to examine the temporal changes in radioactivity and to clarify the variation factor and the effect of radioecology in marine biota. Cs-134 and Cs-137, and Ag-110m, were released by this accident, determined in biota sample such as the plankton, fish and benthos, although it is well-known that molluscs and crustaceans concentrate silver in visceral parts. However, Sr-90 was not detected and the activities of plutonium were almost same level before this accident in the marine biota around off Fukushima. Concentration ratios of Cs (CR-Cs) in marine organism were from 2.6 E+1 in the muscle part of squid to 1.0 E+4 in the viscera of clam. The large differences in CR-Cs by the parts of marine organism were not observed. It is suggested that rapid change in the activities of radio Cs and silver in seawater, resuspension of particles from sediments and food chain effects led to high radionuclide activities in marine biota after this accident. CR-Cs in plankton was also calculated with the activities in seawater, which were collected around sampling area during this monitoring period. These resulting values ranged from 5.8 E+1 to 7.8 E+2

Safety technical investigation activities for shipment of damaged spent fuels from Fukushima Daiichi Nuclear Power Station

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-08-15

Japan Nuclear Energy Safety Organization(JNES) carries out the investigation for damaged fuel transportation from Fukushima Daiichi Nuclear Power Station(1F) under safety condition to support Nuclear Regulation Authority (NRA). In 2012 fiscal year, JNES carried out the investigation of spent fuel condition in unit 4 of 1F and actual result of leak fuel transport in domestic /other countries. From this result, Package containing damaged fuel from unit 4 in 1F were considered. (author)

Evaluation of radiocesium concentrations in new leaves of wild plants two years after the Fukushima Dai-ichi Nuclear Power Plant accident.

Science.gov (United States)

Sugiura, Yuki; Shibata, Michihiro; Ogata, Yoshimune; Ozawa, Hajime; Kanasashi, Tsutomu; Takenaka, Chisato

2016-08-01

Radiocesium ((137)Cs) transfer to plants immediately after the Fukushima Dai-ichi Nuclear Power Plant accident was investigated by collecting newly emerged leaf and soil samples between May 2011 and November 2012 from 20 sites in the Fukushima prefecture. Radiocesium concentrations in leaf and soil samples were measured to calculate concentration ratios (CR). Woody plants exhibited high CR values because (137)Cs deposited on stems and/or leaves were transferred to newly emerging tissues. The CR values in 2012 declined as compared to that in 2011. Exchangeable (137)Cs rates in soil (extraction rate) samples were measured at five sites. These rates decreased at four sites in 2012 and depended on environmental conditions and soil type. Both CR values and extraction rates decreased in 2012. However, CR values reflected the changes in extraction rates and characteristics of each species. Amaranthaceae, Chenopodiaceae, and Polygonaceae, which had been identified as Cs accumulators, presented no clear (137)Cs accumulation ability. In 2012, the perennial plant Houttuynia cordata and deciduous trees Chengiopanax sciadophylloides and Acer crataegifolium displayed high CR values, indicating that these species are (137)Cs accumulators and may be considered as potential species for phytoremediation. Copyright © 2016 Elsevier Ltd. All rights reserved.

A digest of the Nuclear Safety Division report on the Fukushima Dai-ichi accident seminar (4). Issues identified by the accident

International Nuclear Information System (INIS)

Moriyama, Kumiaki; Abe, Kiyoharu

2013-01-01

AESJ Nuclear Safety Division published 'Report on the Fukushima Dai-ichi Accident Seminar - what was wrong and what should been down in future-' which would be published as five special articles of the AESJ journal. The Fukushima Dai-ichi accident identified issues of several activities directly related with nuclear safety in the areas of safety design, severe accident management and safety regulations. PRA, operational experiences and safety research could not always contribute safety assurance of nuclear power plant so much. This article (4) summarized technical issues based on related facts of the accident as much as possible and discussed' what was wrong and what should be down in future'. Important issues were identified from defense-in-depth philosophy and lessons learned on safety design were obtained from accident progression analysis. Activities against external events and continuous improvements of safety standards based on latest knowledge were most indispensable. Strong cooperation among experts in different areas was also needed. (T. Tanaka)

Key regulatory and safety issues emerging NEA activities. Lessons Learned from Fukushima Dai-ichi NPS Accident - Key Regulatory and Safety Issues

International Nuclear Information System (INIS)

Nakoski, John

2013-01-01

A presentation was provided on the key safety and regulatory issues and an update of activities undertaken by the NEA and its members in response to the accident at the Fukushima Daiichi nuclear power stations (NPS) on 11 March 2011. An overview of the accident sequence and the consequences was provided that identified the safety functions that were lost (electrical power, core cooling, and primary containment) that lead to units 1, 2, and 3 being in severe accident conditions with large off-site releases. Key areas identified for which activities of the NEA and member countries are in progress include accident management; defence-in-depth; crisis communication; initiating events; operating experience; deterministic and probabilistic assessments; regulatory infrastructure; radiological protection and public health; and decontamination and recovery. For each of these areas, a brief description of the on-going and planned NEA activities was provided within the three standing technical committees of the NEA with safety and regulatory mandates (the Committee on Nuclear Regulatory Activities - CNRA, the Committee on the Safety of Nuclear Installations - CSNI, and the Committee on Radiation Protection and Public Health - CRPPH). On-going activities of CNRA include a review of enhancement being made to the regulatory aspects for the oversight of on-site accident management strategies and processes in light of the lessons learned from the accident; providing guidance to regulators on crisis communication; and supporting the peer review of the safety assessments of risk-significant research reactor facilities in light of the accident. Within the scope of the CSNI mandate, activities are being undertaken to better understand accident progression; characteristics of new fuel designs; and a benchmarking study of fast-running software for estimating source term under severe accident conditions to support protective measure recommendations. CSNI also has ongoing work in human

Review of off-site emergency preparedness and response plan of Indian NPPs based on experience of Fukushima nuclear accident

International Nuclear Information System (INIS)

Singh, Hukum; Dash, M.; Shukla, Vikas; Vijayan, P.; Krishnamurthy, P.R.

2012-01-01

Nuclear power plants in India are designed, constructed and operated based on the principle of the highest priority to nuclear safety. To deal with any unlikely situation of radiological emergency, the emergency preparedness and response plans are ensured to be in place at all NPPs prior to their commissioning. These plans are periodically reviewed and tested by conducting emergency exercise with the participation of various agencies such as Nuclear Power Corporation of India Limited, NDMA, district authorities, regulatory body and general public. On March 11, 2011 an earthquake of magnitude 9.0 hit the Fukushima Dai-ichi and Dai-ni followed by tsunami waves of height 15 meters above reference sea level. This resulted in large scale release of radioactive material from Fukushima Dai-ichi NPS. This led to the evacuation of a large number of people from the areas surrounding the affected nuclear power plants. The event was rated as level 7 event in International Nuclear Event Scale (INES). The event also revealed the challenges in handling radiological emergency situation in adverse environmental conditions, The experience of managing radiological emergency situation during Fukushima nuclear accident provides opportunities to review and improve emergency preparedness and response programme. The present paper presents the chronology of the emergency situation, challenges faced and handled in Fukushima. Even though the possibility of a Fukushima type nuclear accident in India is very remote due to the low probability of a high intensity earthquake followed by tsunami at NPP sites, the efforts needs to be initiated from the regulatory point of view for an effective Nuclear and Radiological Emergency Preparedness and Response Plans. The Emergency Preparedness and Response Plans of NPP sites were reviewed in the light of unique challenges of accident at Fukushima. It is realized that multi unit events are the realities that must be addressed as part of Emergency

Review of off-site emergency preparedness and response plan of Indian NPPs based on experience of Fukushima nuclear accident

Energy Technology Data Exchange (ETDEWEB)

Singh, Hukum; Dash, M.; Shukla, Vikas; Vijayan, P.; Krishnamurthy, P.R., E-mail: vshukla@aerb.gov.in [Operating Plants Safety Division, Atomic Energy Regulatory Board, Mumbai (India)

2012-07-01

Nuclear power plants in India are designed, constructed and operated based on the principle of the highest priority to nuclear safety. To deal with any unlikely situation of radiological emergency, the emergency preparedness and response plans are ensured to be in place at all NPPs prior to their commissioning. These plans are periodically reviewed and tested by conducting emergency exercise with the participation of various agencies such as Nuclear Power Corporation of India Limited, NDMA, district authorities, regulatory body and general public. On March 11, 2011 an earthquake of magnitude 9.0 hit the Fukushima Dai-ichi and Dai-ni followed by tsunami waves of height 15 meters above reference sea level. This resulted in large scale release of radioactive material from Fukushima Dai-ichi NPS. This led to the evacuation of a large number of people from the areas surrounding the affected nuclear power plants. The event was rated as level 7 event in International Nuclear Event Scale (INES). The event also revealed the challenges in handling radiological emergency situation in adverse environmental conditions, The experience of managing radiological emergency situation during Fukushima nuclear accident provides opportunities to review and improve emergency preparedness and response programme. The present paper presents the chronology of the emergency situation, challenges faced and handled in Fukushima. Even though the possibility of a Fukushima type nuclear accident in India is very remote due to the low probability of a high intensity earthquake followed by tsunami at NPP sites, the efforts needs to be initiated from the regulatory point of view for an effective Nuclear and Radiological Emergency Preparedness and Response Plans. The Emergency Preparedness and Response Plans of NPP sites were reviewed in the light of unique challenges of accident at Fukushima. It is realized that multi unit events are the realities that must be addressed as part of Emergency

Fukushima Daiichi. Post accident countermeasures and mid-and-long-term action plan

International Nuclear Information System (INIS)

Yamashita, Kazuhiko

2012-01-01

Since accident at Fukushima Daiichi nuclear power station, TEPCO had made strenuous efforts to maintain stable cooling of reactors and suppress discharge of radioactive materials under the cooperation of the government and others concerned. Various activities towards settlement of the accident had been done according to the roadmap proposed on April 17, 2011. This article described outlines of post accident countermeasures and current activities toward decommissioning based on mid-and-long-term action plan. Step 2 completion in roadmap towards settlement of the accident was confirmed on Dec. 16, 2011; (1) reactors: attainment of a condition equivalent to 'cold shutdown' with temperature of RPV bottom below 100degC, release of radioactive materials from PCV under control and public radiation exposure by additional release being significantly held down (evaluated as maximum 0.2 mSv/y at the site boundary), and mid-term safety of circulating water injection cooling system, (2) spent fuel pools: more stable cooling with circulating cooling system by installation of heat exchanger, (3) radioactive contaminated water: reduction of total amount with full-fledged processing facilities, desalination processing (reuse), storage and mitigation of contamination in the ocean, (4) commence construction of water shielding wall to prevent contamination of the ocean via the underground water, (5) installation of reactor building cover of unit 1 to restrain release of radioactive materials, and others. According to mid-to-long-term roadmap towards the decommissioning of Fukushima Nuclear Power Units 1-4, current activities were to (1) maintain stable reactor cooling and accumulated water processing and improve their credibility, (2) reduce the radiation impact due to additional emissions from the whole site and radioactive waste generated after the accident, (3) commence removal of fuel from the spent fuel pools (unit 4 within 2 years), (4) commence R and D and decontamination the

A numerical study on oceanic dispersion and sedimentation of radioactive cesium-137 from Fukushima Daiichi Nuclear Power Plant

International Nuclear Information System (INIS)

Higashi, Hironori; Morino, Yu; Ohara, Toshimasa

2014-01-01

We discussed a numerical model for oceanic dispersion and sedimentation of radioactive cesium-137 (Cs-137) in shallow water regions to clarify migration behavior of Cs-137 from Fukushima Daiichi Nuclear Power Plant. Our model considered oceanic transport by three dimensional ocean current, adsorption with large particulate matter (LPM), sedimentation and resuspension. The simulation well reproduced the spatial characteristics of sea surface concentration and sediment surface concentration of Cs-137 off Miyagi, Fukushima, and Ibaraki Prefectures during May-December 2011. The simulated results indicated that the adsorption-sedimentation of Cs-137 significantly occurred during strong wind events because the large amount of LPM was transported to upward layer by resuspension and vertical mixing. (author)

The reactor accident in Fukushima Daiichi. The consequence of design deficiencies and inadequate safety engineering; Der Reaktorunfall in Fukushima Daiichi. Folge fehlerhafter Auslegung und unzureichender Sicherheitstechnik

Energy Technology Data Exchange (ETDEWEB)

NONE

2015-03-15

The reactor accident in Fukushima Daiichi is discussed in the frame of design deficiencies and inadequate safety engineering. The progress of the accident as consequence of the earthquake and the tsunami is described. The radiological situation for the public is supposed to be blow the dose limit of 20 mSv/year. The WHO and UNSCEAR (United Nations Scientific Committee on the Effects of Atomic radiation) did not observe acute radiation injuries. The Japanese authorities have classified the accident to 7 of the INES scale. The German Atomforum e.V. considers the safety engineering of German NPPs to be superior to the Japanese situation due to higher emergency energy supply, extensive measures to reduce the hydrogen accumulation and mitigating measures for the accident management. German NPPS are considered highly robust as the EU stress tests have shown.

Enhancement of organizational resilience in light of the Fukushima Dai-ichi Nuclear Power Plant accident (1). Analysis of responding structure

International Nuclear Information System (INIS)

Yoshizawa, Atsufumi; Furuhama, Yutaka; Mutou, Keiko; Oba, Kyoko; Kitamura, Masaharu

2014-01-01

Through the critical situations experienced at the Fukushima Daiichi Nuclear Power Plant accident, it became evident that plant personnel are the essential driving force toward resilience for mitigating the severe nuclear accident. In such situation, the key factors are skill and attitude of human operators who struggled sincerely against the accident. It is also evident that future nuclear safety needs to aim at Safety- which is a newly introduced notion of safety proposed in conjunction with resilience engineering. Safety-I was defined as a condition where as little as possible went wrong;. Safety-II is defined as a condition where as much as possible goes wright. Among the four core capabilities (i.e. Learning, Responding, Monitoring, Anticipating) proposed in the framework of resilience engineering, the constituents of 'Responding' is mainly studied in this paper. Four constituents such as Skill Attitude, Health and Environment have been identified through in-depth reviewing of accident reports and reflection of one of the authors who served as a unit director of Fukushima Daiichi Nuclear Power Plant. (author)

Research of the improvement of the process, organization, etc. related to the emergency correspondence of JNES based on the cause analysis about emergency correspondence of JNES in case of the Fukushima Dai-ichi nuclear power plant accident

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-08-15

At the time of the occurrence of the Fukushima Dai-ichi nuclear power plant accident, JNES implemented various emergency correspondences. On the other hand, various organizations published the report about the Fukushima Dai-ichi nuclear power plant accident. In them, the problems about the regulatory body's regulatory process, regulatory organization, etc. are also pointed out. JNES is a designated public institution. JNES is required to improve process, organization, etc. related to emergency correspondence continuously based on the lessons learned obtained from the emergency corresponding experience about the Fukushima Dai-ichi nuclear power plant accident. Specifically, the following activities will be implemented in the 2014 and 2015 fiscal year. 1. Collect systematically and comprehensively the information about emergency correspondence of JNES in case of the Fukushima Dai-ichi nuclear power plant accident, and create the timeline of the event. 2. Specify problems and analyze human factors and organizational factors. 3. Specify the requirements for establishing a designated public institution's emergency correspondence based on the viewpoint of a human and an organization. 4. Publish the report which indicates collected information, the contents of analysis, proposals of improvement, etc. (author)

Updated synthesis of the knowledge about the impact on marine environment of the radioactive releases from Fukushima Dai-ichi damaged site - October 26, 2011; Synthese actualisee des connaissances relatives a l'impact sur le milieu marin des rejets radioactifs du site nucleaire accidente de Fukushima Dai-ichi - 26 octobre 2011

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-10-26

A strong radioactive contamination of the marine environment close to the damaged Fukushima Dai-ichi power plant has been observed since March 21. The high concentration of some nuclides ({sup 131}I, {sup 137}Cs, {sup 134}Cs, {sup 136}Cs, {sup 132}Te, {sup 132}I) comes from three possible sources: the liquid effluents from the damaged site, the atmospheric fallouts, and the weathering of contaminated soils. This information note presents and comments the most recent informations gathered by the French institute of radiation protection and nuclear safety (IRSN) since the previous information note from July 11 and devoted to the same topic. It presents the estimation of the relative contribution of each contamination source and the evolution with time of the marine contamination. The mapping of {sup 137}Cs concentrations in surface seawater allows to estimate the amount of total {sup 137}Cs in the marine environment and its evolution with time. {sup 137}Cs and {sup 134}Cs concentrations were measured both in samples of surface coastal sediments and in river fishes and seafood products (mainly fishes and molluscs). Results are reported in graphs showing their evolution with time. (J.S.)

Time changes in radiocesium wash-off from various land uses after the Fukushima Daiichi NPP accident

Science.gov (United States)

Onda, Yuichi; Kato, Hiroaki; Yoshimura, Kazuya; Tsujimura, Maki; Wakiyama, Yoshifumi; Taniguchi, Keisuke; Sakaguchi, Aya; Yamamoto, Masayoshi

2014-05-01

A number of studies have been conducted to monitor and model the time series change of radiocesium transfer through aquatic systems after significant fallout, especially from the Chernobyl disaster. However, no data is available for the temporal changes of radiocesium concentration in environmental materials such as soil and water after the Fukushima Daiichi nuclear power plant accident. Our research team has been monitoring the environmental consequences of radioactive contamination just after the Fukushima Daiichi NPP accident in Yamakiya-district, Kawamata town, Fukushima prefecture. Research items are listed below. 1. Radiocesium wash-off from the runoff-erosion plot under different land use. 2. Measurement of radiocesium transfer in forest environment, in association with hydrological pathways such as throughfall and overlandflow on hillslope. 3. Monitoring on radiocesium concentration in soil water, ground water, and spring water. 4. Monitoring of dissolved and particulate radiocesium concentration in river water, and stream water from the forested catchment. 5.Measurement of radiocesium content in drain water and suspended sediment from paddy field. Our monitoring result demonstrated that the Cs-137 concentration in eroded sediment from the runoff-erosion plot has been almost constant for the past 3 years, however the Cs-137 concentration of suspended sediment from the forested catchment showed slight decrease through time. On the other hand, the suspended sediment from paddy field and those in river water from large catchments exhibited rapid decrease in Cs-137 concentration with time. The decreasing trend of Cs-137 concentration were fitted by the two-component exponential model, differences in decreasing rate of the model were compared and discussed among various land uses and catchment scales. Such analysis can provide important insights into the future prediction of the radiocesium wash-off from catchments with different land uses.

Radioactivity around Fukushima Daiichi Nuclear Power Plant 9 months after the disaster

International Nuclear Information System (INIS)

Shozugawa, Katsumi

2012-01-01

We have measured radioactivities around Fukushima Daiichi Nuclear Power Plant in December, 2011, 9 months after the disaster, to compare with measurements in April, 2011. The radioactivity originated by radioactive iodine should have disappeared before December due to its comparatively short lifetime. At the point 1.5km apart from the Plant, the dose rate 1m above the earth was 78 μ Sv/h in April whereas it was 56 μ Sv/h in December, which was higher than anticipation. The measured radioactivities of the soil of fields and forests around the Plant in December were even four times higher than those in April. These phenomena may be resulted with the movement of soil particles attached with radioactive cesium by rainwater or wind. (author)

Interim report on the accident at Fukushima Nuclear Power Stations of Tokyo Electric Power Company

International Nuclear Information System (INIS)

2011-12-01

The Investigation Committee on the Accident at the Fukushima Nuclear Power Stations (the Investigation Committee) of Tokyo Electric Power Company (TEPCO) was established by the Cabinet decision on May 24, 2011. Its objectives are: to conduct investigation for finding out the causes of accidents at the Fukushima Dai-ichi Nuclear Power Station (Fukushima Dai-ichi NPS) and Fukushima Dai-ni Nuclear Power Station (Fukushima Dai-ni NPS) of TEPCO as well as the causes of accident damage; and to make policy recommendations for limiting the expansion of damage and preventing reoccurrence of similar accidents. The Investigation Committee has conducted its investigation and evaluation since its first meeting on June 7, 2011. Its activities included: site visits to the Fukushima Dai-ichi and Dai-ni NPSs, as well as to other facilities; hearing of heads of local governments around the Fukushima Dai-ichi NPS; and hearing of people concerned through interviews mainly arranged by the Secretariat. As of December 16, 2011, the number of interviewees reached 456. The investigation and evaluation by the Investigation Committee are still ongoing and the Interim Report does not cover every item that the Committee aims at investigating and evaluating. Fact-finding of even some of those items discussed in the Interim Report are not yet completed. The Investigation Committee continues to conduct its investigation and evaluation and will issue its Final Report in the summer of 2012. This brief executive summary covers mainly considerations and evaluation of the issues in Chapter VII of the Interim Report, with brief reference to Chapters I to VI. The Investigation Committee recommendations are printed in bold. (author)

Fukushima Daiichi-Derived Radionuclides in the Ocean: Transport, Fate, and Impacts.

Science.gov (United States)

Buesseler, Ken; Dai, Minhan; Aoyama, Michio; Benitez-Nelson, Claudia; Charmasson, Sabine; Higley, Kathryn; Maderich, Vladimir; Masqué, Pere; Morris, Paul J; Oughton, Deborah; Smith, John N

2017-01-03

The events that followed the Tohoku earthquake and tsunami on March 11, 2011, included the loss of power and overheating at the Fukushima Daiichi nuclear power plants, which led to extensive releases of radioactive gases, volatiles, and liquids, particularly to the coastal ocean. The fate of these radionuclides depends in large part on their oceanic geochemistry, physical processes, and biological uptake. Whereas radioactivity on land can be resampled and its distribution mapped, releases to the marine environment are harder to characterize owing to variability in ocean currents and the general challenges of sampling at sea. Five years later, it is appropriate to review what happened in terms of the sources, transport, and fate of these radionuclides in the ocean. In addition to the oceanic behavior of these contaminants, this review considers the potential health effects and societal impacts.

[Measures against Radiation Exposure Due to Large-Scale Nuclear Accident in Distant Place--Radioactive Materials in Nagasaki from Fukushima Daiichi Nuclear Power Plant].

Science.gov (United States)

Yuan, Jun; Sera, Koichiro; Takatsuji, Toshihiro

2015-01-01

To investigate human health effects of radiation exposure due to possible future nuclear accidents in distant places and other various findings of analysis of the radioactive materials contaminating the atmosphere of Nagasaki due to the Fukushima Daiichi Nuclear Power Plant accident. The concentrations of radioactive materials in aerosols in the atmosphere of Nagasaki were measured using a germanium semiconductor detector from March 2011 to March 2013. Internal exposure dose was calculated in accordance with ICRP Publ. 72. Air trajectories were analyzed using NOAA and METEX web-based systems. (134)Cs and (137)Cs were repeatedly detected. The air trajectory analysis showed that (134)Cs and (137)Cs flew directly from the Fukushima Daiichi Nuclear Power Plant from March to April 2011. However, the direct air trajectories were rarely detected after this period even when (134)Cs and (137)Cs were detected after this period. The activity ratios ((134)Cs/(137)Cs) of almost all the samples converted to those in March 2011 were about unity. This strongly suggests that the (134)Cs and (137)Cs detected mainly originated from the Fukushima Daiichi Nuclear Power Plant accident in March 2011. Although the (134)Cs and (137)Cs concentrations per air volume were very low and the human health effects of internal exposure via inhalation is expected to be negligible, the specific activities (concentrations per aerosol mass) were relatively high. It was found that possible future nuclear accidents may cause severe radioactive contaminations, which may require radiation exposure control of farm goods to more than 1000 km from places of nuclear accidents.

Fukushima Daiichi Unit 1 Ex-Vessel Prediction: Core Concrete Interaction

International Nuclear Information System (INIS)

Robb, Kevin R; Farmer, Mitchell; Francis, Matthew W

2015-01-01

Lower head failure and corium concrete interaction were predicted to occur at Fukushima Daiichi Unit 1 (1F1) by several different system-level code analyses, including MELCOR v2.1 and MAAP5. Although these codes capture a wide range of accident phenomena, they do not contain detailed models for ex-vessel core melt behavior. However, specialized codes exist for analysis of ex-vessel melt spreading (e.g., MELTSPREAD) and long-term debris coolability (e.g., CORQUENCH). On this basis, an analysis was carried out to further evaluate ex-vessel behavior for 1F1 using MELTSPREAD and CORQUENCH. Best-estimate melt pour conditions predicted by MELCOR v2.1 and MAAP5 were used as input. MELTSPREAD was then used to predict the spatially dependent melt conditions and extent of spreading during relocation from the vessel. The results of the MELTSPREAD analysis are reported in a companion paper. This information was used as input for the long-term debris coolability analysis with CORQUENCH.

Fungal levels in houses in the Fukushima Daiichi Nuclear Power Plant evacuation zone after the Great East Japan Earthquake.

Science.gov (United States)

Shinohara, Naohide; Tokumura, Masahiro; Hashimoto, Kazuhiro; Asano, Katsuyoshi; Kawakami, Yuji

2017-10-01

Residences located within 20 km of the damaged Fukushima Daiichi Nuclear Power Plant were evacuated shortly after the Great East Japan Earthquake. The levels of airborne and surface fungi were measured in six houses in the evacuation zone in August 2012 and February 2013. Airborne fungal levels in all of the houses in the summer were higher than the environmental standard levels for residential houses published in Architectural Institute of Japan (>1000 colony-forming units [CFU]/m 3 ). In two houses whose residents rarely returned to visit, fungal levels were extremely high (>52,000 CFU/m 3 ). Although fungal levels in the winter were much lower than those in the summer, they were still higher than environmental standard levels in several houses. Indoor fungal levels were significantly inversely related to the frequency with which residents returned, but they were not correlated with the air exchange rates, temperature, humidity, or radiation levels. Cladosporium spp. and Penicillium spp. were detected in every house. Aspergillus section Circumdati (Aspergillus ochraceus group) was also detected in several houses. These fungi produced ochratoxin A and ochratoxin B, which have nephrotoxic and carcinogenic potential. The present study suggests that further monitoring of fungal levels is necessary in houses in the Fukushima Daiichi Nuclear Power Plant evacuation zone, and that some houses may require fungal disinfection. The results suggest that residents' health could be at risk owing to the high levels of airborne fungi and toxic fungi Aspergillus section Circumdati. Therefore, monitoring and decontamination/disinfection of fungi are strongly recommended before residents are allowed to return permanently to their homes. In addition, returning to home with a certain frequency and adequate ventilation are necessary during similar situations, e.g., when residents cannot stay in their homes for a long period, because fungal levels in houses in the Fukushima Daiichi

Tracking of Airborne Radionuclides from the Damaged Fukushima Dai-Ichi Nuclear Reactors by European Networks

DEFF Research Database (Denmark)

Masson, O.; Baeza, A.; Bieringer, J.

2011-01-01

Radioactive emissions into the atmosphere from the damaged reactors of the Fukushima Dai-ichi nuclear power plant (NPP) started on March 12th, 2011. Among the various radionuclides released, iodine-131 (131I) and cesium isotopes (137Cs and 134Cs) were transported across the Pacific toward the North...... period and spatial variations across more than 150 sampling locations in Europe made it possible to characterize the contaminated air masses. After the Chernobyl accident, only a few measurements of the gaseous 131I fraction were conducted compared to the number of measurements for the particulate...... reactors have provided a significant amount of new data on the ratio of the gaseous 131I fraction to total 131I, both on a spatial scale and its temporal variation. It can be pointed out that during the Fukushima event, the 134Cs to 137Cs ratio proved to be different from that observed after the Chernobyl...

ABWR1. A Generation III.7 reactor after the Fukushima Daiichi accident

International Nuclear Information System (INIS)

Sato, Takashi; Matsumoto, Keiji; Kurosaki, Toshikazu; Taguchi, Keisuke

2015-01-01

iB1350 stands for an innovative, intelligent and inexpensive BWR 1350. It is the first Generation III.7 reactor after the Fukushima Daiichi accident. It has incorporated lessons learned from the Fukushima Daiichi accident and WENRA safety objectives. It has innovative safety to cope with devastating natural disasters including a giant earthquake, a large tsunami and a monster hurricane. The iB1350 can survive passively such devastation and a very prolonged SBO without any support from the outside of a site up to 7 days even preventing core melt. It, however, is based on the well-established proven ABWR design. The NSSS is exactly the same as that of the current ABWR. As for safety design it has a double cylinder RCCV (Mark W containment) and an in-depth hybrid safety system (IDHS). The Mark W containment has double FP confinement barriers and the in-containment filtered venting system (IFVS) that enable passively no emergency evacuation outside the immediate vicinity of the plant for a SA. It has a large volume to hold hydrogen, a core catcher, a passive flooding system and an innovative passive containment cooling system (iPCCS) establishing passively practical elimination of containment failure even in a long term. The IDHS consists of 4 division active safety systems for a DBA, 2 division active safety systems for a SA and built-in passive safety systems (BiPSS) consisting of an isolation condenser (IC) and the iPCCS for a SA. The IC/PCCS pools have enough capacity for 7 day grace period. The IC/PCCS heat exchangers, core and spent fuel pool are enclosed inside the CV building and protected against a large airplane crash. The iB1350 can survive a large airplane crash only by the CV building and the built-in passive safety systems therein. The dome of the CV building consists of a single wall made of steel and concrete composite. This single dome structure facilitates a short-term construction period and cost saving. The CV diameter is smaller than that of most

Status of the spent fuel in the reactor buildings of Fukushima Daiichi 1–4

Energy Technology Data Exchange (ETDEWEB)

Jäckel, Bernd S., E-mail: bernd.jaeckel@psi.ch

2015-03-15

The ratios of the radionuclides Cs-134g and Cs-137 deduced from measurements of liquid samples from the spent fuel pools in Fukushima Daiichi 1–4 are used to interpret the status of the spent fuel assemblies in the pools of the damaged reactor buildings. The different natures of the production of Cs-134g (neutron capture product of Cs-133) and Cs-137 (cumulative fission product from mass chain 137) and the different half-lives (2.06 years and 30.17 years respectively) require a complicated calculation of the mass and activity of the two nuclides. These masses are depending on the local burn up of the fuel, the burn up history and the radioactive decay. Calculation of the neutron capture product Cs-134g is particularly complicated, because the production of Cs-133 (stable cumulative fission product from mass chain 133) has to be taken into account. The neutron capture cross section for Cs-133 for thermal neutrons is well known, but the energy spectrum of the neutrons in a reactor includes higher energies according to the degree of moderation. Therefore the cross section was fitted from a gamma scan of spent fuel rods in a hot cell. The method of the calculation of the nuclide activities and the interpretation of the gamma measurements of the spent fuel pool samples from Fukushima Daiichi 1–4 are described in detail. It could be shown that at most only very minor mechanical damage of some spent fuel elements occurred during the accident and the later phase of the clearing work.

Fukushima Daiichi Nuclear Power Plant accident: facts, environmental contamination, possible biological effects, and countermeasures.

Science.gov (United States)

Anzai, Kazunori; Ban, Nobuhiko; Ozawa, Toshihiko; Tokonami, Shinji

2012-01-01

On March 11, 2011, an earthquake led to major problems at the Fukushima Daiichi Nuclear Power Plant. A 14-m high tsunami triggered by the earthquake disabled all AC power to Units 1, 2, and 3 of the Power Plant, and carried off fuel tanks for emergency diesel generators. Despite many efforts, cooling systems did not work and hydrogen explosions damaged the facilities, releasing a large amount of radioactive material into the environment. In this review, we describe the environmental impact of the nuclear accident, and the fundamental biological effects, acute and late, of the radiation. Possible medical countermeasures to radiation exposure are also discussed.

Dispersion and fate of {sup 90}Sr in the Northwestern Pacific and adjacent seas: Global fallout and the Fukushima Dai-ichi accident

Energy Technology Data Exchange (ETDEWEB)

Maderich, V., E-mail: vladmad@gmail.com [Institute of Mathematical Machine and System Problems, Glushkov av., 42, Kiev 03187 (Ukraine); Jung, K.T., E-mail: ktjung@kiost.ac [Korea Institute of Ocean Science and Technology, 787, Haean-ro, Ansan 426-744 (Korea, Republic of); Bezhenar, R., E-mail: romanbezhenar@gmail.com [Ukrainian Center of Water and Environmental Projects, Glushkov av., 42, Kiev 03187 (Ukraine); With, G. de, E-mail: g.dewith@nrg.eu [NRG, Utrechtseweg 310, 6800 ES Arnhem (Netherlands); Qiao, F., E-mail: qiaofl@fio.org.cn [First Institute of Oceanography, 6 Xianxialing Road, Qingdao 266061 (China); Casacuberta, N., E-mail: ncasacuberta@phys.ethz.ch [Laboratory of Ion Beam Physics, ETH-Zurich, Schafmattstrasse 20, 8093 Zurich (Switzerland); Masque, P., E-mail: pere.masque@uab.cat [Institut de Ciència i Tecnologia Ambientals and Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain); Kim, Y.H., E-mail: yhkimstar@gmail.com [Korea Institute of Ocean Science and Technology, 787, Haean-ro, Ansan 426-744 (Korea, Republic of)

2014-10-01

The 3D compartment model POSEIDON-R was applied to the Northwestern Pacific and adjacent seas to simulate the transport and fate of {sup 90}Sr in the period 1945–2010 and to perform a radiological assessment on the releases of {sup 90}Sr due to the Fukushima Dai-ichi nuclear accident for the period 2011–2040. The contamination due to runoff of {sup 90}Sr from terrestrial surfaces was taken into account using a generic predictive model. A dynamical food-chain model describes the transfer of {sup 90}Sr to phytoplankton, zooplankton, molluscs, crustaceans, piscivorous and non-piscivorous fishes. Results of the simulations were compared with observation data on {sup 90}Sr for the period 1955–2010 and the budget of {sup 90}Sr activity was estimated. It was found that in the East China Sea and Yellow Sea the riverine influx was 1.5% of the ocean influx and it was important only locally. Calculated concentrations of {sup 90}Sr in water, bottom sediment and marine organisms before and after the Fukushima Dai-ichi accident are in good agreement with available experimental measurements. The concentration of {sup 90}Sr in seawater would return to the background levels within one year after leakages were stopped. The model predicts that the concentration of {sup 90}Sr in fish after the Fukushima Dai-ichi accident shall return to the background concentrations only 2 years later due to the delay of the transfer throughout the food web and specific accumulation of {sup 90}Sr. The contribution of {sup 90}Sr to the maximal dose rate due to the FDNPP accident was three orders of magnitude less than that due to {sup 137}Cs, and thus well below the maximum effective dose limits for the public. - Highlights: • A box model with a dynamical food-chain model for the NW Pacific was applied. • The transport and fate of {sup 90}Sr in sea were simulated for the period 1945–2040. • Marine exposure pathways for {sup 90}Sr were assessed for the Fukushima Dai-ichi accident. �

Lessons Learned from the Fukushima Daiichi Accident, Actions Taken and Challenges Ahead

International Nuclear Information System (INIS)

Shimizu, Y.

2016-01-01

On 19 September, 2012, the Nuclear Regulation Authority (NRA) was established in light of lessons learned from the Fukushima Daiichi accident of 11 March 2011, to ensure that such accidents never happen again, to restore public trust in regulator both in Japan and abroad and to rebuild and foster a genuine safety culture by placing the highest priority on public safety. The NRA, an independent administrative commission of the Ministry of the Environment, is organized to separate the regulatory functions from the promotional functions of the use of nuclear energy within the government, and to independently implement its duties from the perspectives of neutrality and fairness based on its expertise. Having learned the lessons from the Fukushima Daiichi accident and with reference to IAEA safety standards, since its establishment, the NRA has endeavored to strengthen the regulatory requirements, in particular, for hazards such as tsunamis and earthquakes which may lead to common cause failures, and countermeasures against severe accidents. Under the new regulatory scheme, a back-fitting system was introduced. Emergency preparedness and response measures for nuclear facilities were also enhanced. As of end of March 2016, five reactors received NRA’s permission for changing their reactor installations based on the new regulatory requirements, and two nuclear power reactors have restarted their operations. In January 2016, at the request of Japan, the IAEA sent the IRRS mission team to Japan to assess the regulatory framework for nuclear and radiation safety. Through the self-assessment prior to the mission, the NRA has developed 22 action plans, including a) improvement of regulatory inspection, b) capacity building, and c) strengthening of safety research capability. The mission team has found that Japan’s nuclear regulator has demonstrated independence and transparency since it was set up in 2012. The team also noted that the NRA needs to improve the inspection

Radiocesium contamination of the web spider Nephila clavata (Nephilidae: Arachnida) 1.5 years after the Fukushima Dai-ichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Ayabe, Yoshiko; Kanasashi, Tsutomu; Hijii, Naoki; Takenaka, Chisato

2014-01-01

We measured the concentrations of radiocesium ( 134 Cs and 137 Cs) in a large web spider, Nephila clavata L. Koch (Nephilidae: Arachnida), collected at three sites at different distances from the Fukushima Dai-ichi Nuclear Power Plant about 1.5 y after the accident in March 2011. The radiocesium concentrations in spiders were highest in a streamside secondary forest 33 km northwest of the power plant: mean ± a standard deviation of 2.401 ± 1.197 Bq g −1 dry for 134 Cs and 3.955 ± 1.756 Bq g −1 dry for 137 Cs. In a hillside secondary forest 37 km northwest of the power plant, the mean concentrations of 134 Cs and 137 Cs were 0.825 ± 0.247 Bq g −1 dry and 1.470 ± 0.454 Bq g −1 dry, respectively. In a pine forest 62 km west of the power plant, very low radiocesium concentrations were detected, but in only a few individuals. The concentrations of 134 Cs and 137 Cs in spiders collected at each site tended to be correlated with the air radiation dose rate at each site. Since spiders are key components of food webs in forests, the high concentrations in this species at contaminated sites suggested that the radiocesium from the accident has transferred through food chains and reached to higher trophic level of the food chains. -- Highlights: • We investigated radiocesium contamination of large web spiders in Fukushima. • Spiders collected at three different sites in Fukushima were contaminated. • Radiocesium concentrations of spiders tended to increase with the air radiation dose rates. • Radiocesium concentrations of spiders did not affect by the amount of prey

Regional long-term model of radioactivity dispersion and fate in the Northwestern Pacific and adjacent seas: application to the Fukushima Dai-ichi accident

International Nuclear Information System (INIS)

Maderich, V.; Bezhenar, R.; Heling, R.; With, G. de; Jung, K.T.; Myoung, J.G.; Cho, Y.-K.; Qiao, F.; Robertson, L.

2014-01-01

The compartment model POSEIDON-R was modified and applied to the Northwestern Pacific and adjacent seas to simulate the transport and fate of radioactivity in the period 1945–2010, and to perform a radiological assessment on the releases of radioactivity due to the Fukushima Dai-ichi accident for the period 2011–2040. The model predicts the dispersion of radioactivity in the water column and in sediments, the transfer of radionuclides throughout the marine food web, and subsequent doses to humans due to the consumption of marine products. A generic predictive dynamic food-chain model is used instead of the biological concentration factor (BCF) approach. The radionuclide uptake model for fish has as a central feature the accumulation of radionuclides in the target tissue. The three layer structure of the water column makes it possible to describe the vertical structure of radioactivity in deep waters. In total 175 compartments cover the Northwestern Pacific, the East China and Yellow Seas and the East/Japan Sea. The model was validated from 137 Cs data for the period 1945–2010. Calculated concentrations of 137 Cs in water, bottom sediments and marine organisms in the coastal compartment, before and after the accident, are in close agreement with measurements from the Japanese agencies. The agreement for water is achieved when an additional continuous flux of 3.6 TBq y −1 is used for underground leakage of contaminated water from the Fukushima Dai-ichi NPP, during the three years following the accident. The dynamic food web model predicts that due to the delay of the transfer throughout the food web, the concentration of 137 Cs for piscivorous fishes returns to background level only in 2016. For the year 2011, the calculated individual dose rate for Fukushima Prefecture due to consumption of fishery products is 3.6 μSv y −1 . Following the Fukushima Dai-ichi accident the collective dose due to ingestion of marine products for Japan increased in 2011 by a

The Fukushima accident

International Nuclear Information System (INIS)

Maqua, M.; Stueck, R.

2012-01-01

On 11 March 2011, the Tohoku earthquake and the subsequent tsunami hit the Japanese east coast, causing more than 15,000 fatalities. To this date, 3,000 people are still missing. The Fukushima Dai-ichi NPP was the nuclear installation that was most affected by the tsunami. The earthquake cut off the NPP from the national grid. About 45 minutes later, the tsunami flooded units 1-4 and led to core meltdown events with large releases for units 1, 2 and 3. Unit 4 had been in refuelling outage at that time and lost the cooling of the spent fuel pool for several days. Considerable hydrogen explosions occurred in units 1, 3 and 4. Shortly after the accident, TEPCO started to mitigate the consequences of the accident by providing external cooling to the reactors and by removing the radioactive debris from the site. Great emphasis was laid on effective radiation protection measures for the clean-up workers. Thus, up to now there has been no fatality due to the radiation caused by the Fukushima accident. The main steps of the accident sequences are described, taking into account the latest findings of investigations performed by TEPCO or on behalf of the regulatory body. The presentation focuses on the description of the status of the Fukushima Dai-ichi nuclear power plant and the future steps for cleaning-up the site. In the presentation, the major phases of the roadmap that TEPCO has developed for the clean-up are highlighted. The risks associated with the current plant status and the clean-up phases are described. Abstract the content of the manuscript in a few lines.

Consumer Perceptions of Seafood Industries in the Wake of the Deepwater Horizon Oil Spill and Fukushima Daiichi Nuclear Disaster

OpenAIRE

McKendree, Melissa G.S.; Ortega, David L.; Widmar, Nicole Olynk; Wang, H. Holly

2013-01-01

The impact of environmental disasters on consumers’ perceptions and preferences for specific food items has seldom been studied in the applied economics literature. Recent aquatic disasters, namely the Deepwater Horizon Oil Spill and Fukushima Daiichi Nuclear Disaster, have had profound impacts on fisheries serving US consumers and on agribusinesses within the aquaculture industry. This study explores consumer preferences using a nation-wide representative sample, and finds that twenty-nine p...

Tracking Radioactive Fallout from the Fukushima Dai-ichi Accident in Arctic Snow

Science.gov (United States)

Osterberg, E. C.; Thompson, J.; Landis, J.; Albert, M. R.; Campbell, S. W.; Hawley, R. L.; Virginia, R. A.

2011-12-01

The March 11, 2011 magnitude 9.0 Tohoku, Japan earthquake produced a tsunami that inundated the Fukushima Dai-ichi nuclear power plant and led to the accidental release of radioactive 131I, 132Te, 134Cs, and 137Cs to the atmosphere. The Japanese Nuclear Safety Commission estimates that 12,000 TBq of 137Cs were released to the atmosphere during the incident, which represents ~14% of the total estimated 137Cs emission from the Chernobyl disaster in April 1986. Measurements of airborne radiation collected at the Fukushima plant illustrate that >50% of the total emitted radiation was released on March 15 and 16 associated with explosions and fires at reactor units 1, 2, and 4, and 70% was emitted in the first 5 days of the event. The source of the radiation is thus well constrained in time and space, providing an opportunity to better understand long-range atmospheric transport processes from Asia to the Arctic, while also assessing the magnitude of the fallout in the Arctic. Here we describe the 137Cs and 134Cs fallout flux near Thule, Greenland (1700 m a.s.l.), at Summit (3200 m a.s.l.), Greenland, and within Denali National Park, Alaska (2400-3900 m a.s.l.) based on series of large-volume (5-15 l) snow pit samples collected in June and July, 2011. In addition to assessing the spatial variability of Fukushima fallout in the Arctic, the elevation range of samples allows for an analysis of any vertical heterogeneity in fallout transport and deposition. Major ion concentrations and stable water isotope ratios are used to confirm the seasonal timing of the Fukushima fallout horizon in the snowpack. Radiocesium was concentrated and isolated from the snow pit meltwater using the well-established ammonium phosphomolybdate (AMP) adsorption method, and 134Cs and 137Cs concentrations were measured using gamma spectrometry with a Canberra 3523 well-type intrinsic Ge-detector at the Dartmouth College Short-Lived Isotope Laboratory. NOAA HYPLIT atmospheric forward

Radiation protection management in Fukushima Daiichi NPS and post-accident measures

International Nuclear Information System (INIS)

Takahira, Shiro

2014-01-01

Fukushima Daiichi Nuclear Power Station was hit by the big earthquake and tsunami, which caused the station black out and subsequent loss of cooling functions for reactor and spent fuel pools (SFPs). Consequently the fuels were damaged, hydrogen explosion blew off top of the reactor buildings and radioactive materials were released to the atmosphere and the ocean. Tsunami and power loss caused many difficulties of monitoring, dose management, and radiation protection of workers. For example, the radiation management system was down and about 5,000 Alarm Pocket Dosimeters (APDs) and their battery chargers could not be used. Due to the insufficient number of APDs, one representative of each working team had a dosimeter under the limited conditions. Through the accident, we got following lessons learned; (1) Reinforcing monitoring posts, (2) Preparing more radiation protection equipment, (3) Establishing emergency access control centre, and (4) Education and training in radiation protection. (author)

Radiocesium contamination of the moss Hypnum plumaeforme caused by the Fukushima Dai-ichi Nuclear Power Plant accident.

Science.gov (United States)

Oguri, Emiko; Deguchi, Hironori

2018-03-07

We investigated 134 Cs and 137 Cs activity concentrations in the common Japanese moss species Hypnum plumaeforme collected from 32 sites within ca. 100 km radius of the Fukushima Dai-ichi Nuclear Power Plant. A total of 32 samples of H. plumaeforme were collected during the field surveys from November 2013 to September 2014. The maximum radiocesium activity concentrations in H. plumaeforme were 60.9 ± 1.8 kBq kg -1 for 134 Cs and 123 ± 2.3 kBq kg -1 for 137 Cs. The mean value for the 134 Cs/ 137 Cs was 1.17 ± 0.05, and the mean T ag value was 0.09 ± 0.13. Positive correlations were obtained between total 134 Cs + 137 Cs activity concentrations in H. plumaeforme and the air dose rate with a correlation coefficient (r) of 0.55 (P = 0.001), and between 137 Cs activity concentration in H. plumaeforme and 137 Cs deposition density on soil with r of 0.55 (P = 0.001). These results suggest that the perennial moss species H. plumaeforme could be more suitable and useful as a qualitative indicator for the radiocesium pollution compared to vascular plants spreading over the lowlands including human habitation in Fukushima Prefecture. Copyright © 2018. Published by Elsevier Ltd.

Geographical distribution of radioactive nuclides released from the Fukushima Daiichi Nuclear Power Station accident in eastern Japan

International Nuclear Information System (INIS)

Ishida, Masanobu; Umetsu, Kohei; Sugimoto, Miyabi; Yamaguchi, Yuta; Yamazaki, Hideo; Nakagawa, Ryota

2013-01-01

The geographical distribution of radioactive nuclides released from the Fukushima Daiichi Nuclear Power Station accident in metropolitan areas located in eastern Japan was investigated. The radioactive contamination of environmental samples, including soil and biological materials, was analyzed. The concentrations of 131 I, 134 Cs, and 137 Cs in the soil samples collected from Fukushima City were 122000, 11500 and 14000 Bq/kg on 19th March 2011 and 129000, 11000 and 13700 Bq/kg on 26th March 2011, for the three nuclides respectively. The concentrations of 131 I, 134 Cs and 137 Cs in the soil samples collected from March-June 2011 from study sites ranged from 240 to 101000, 28 to 26200, and 14 to 33700 Bq/kg, respectively. In Higashiosaka City, it began to detect those radioactive nuclides in the atmospheric airborne dust from 25th March. Radioactive fission products 95 Zr- 95 Nb were detected on 18th April 2011. Biological samples collected from Tokyo Bay were studied. The maximum concentrations of 134 Cs and 137 Cs detected in the biological samples were 12.2 and 19.2 Bq/kg, which were measured in goby. 131 I was not detected in the biological samples however, trace amounts of the short half-life nuclide 110m Ag were found in the shellfish samples. (author)

Initial and present situation of food contamination in Japan after the accident at the Fukushima Dai-Ichi Nuclear Power Plant

International Nuclear Information System (INIS)

Aono, Tatsuo; Yoshida, Satoshi; Akashi, Makoto

2016-01-01

The accident at the Fukushima Dai-ichi Nuclear Power Plant (NPP) in March 2011 affected not only the terrestrial environment of Fukushima prefecture and the surrounding area, but also the marine area facing the NPP. Our present study is focused on the concentrations of radionuclides in agricultural products of Fukushima and sea-foods collected off Fukushima after the accident. The regulation value for radiocesium in vegetables, meat and fish was revised from 500 Bq/kg-wet to 100 Bq/kg-wet on 1 April 2012. The overall activity of radiocesium in these products was found to be within the limit of tolerance in respect to Japanese and also international regulations, but there is still radiocesium found at activities greater than this level in edible wild plants, wild mushrooms and game such as boar meat. Although the activities of radionuclides exceeding the regulatory limits were not detected in marine products collected off Fukushima after April 2015, the commercial marine fishery has not received approval in the affected areas except for certain species. We learned from the Fukushima accident that long-term kinetic studies of radionuclides in terrestrial and marine environments is extremely important for prevention of internal contamination, since contamination with radionuclides occurs via the food chain in the environment. (authors)

Proceedings of the international symposium on environmental monitoring and dose estimation of residents after accident of TEPCO's Fukushima Daiichi Nuclear Power Stations

International Nuclear Information System (INIS)

Takahashi, Sentaro; Yamana, Hajimu; Takahashi, Tomoyuki; Takamiya, Koichi; Fukutani, Satoshi; Sato, Nobuhiro; Nakatani, Maki

2013-02-01

In March 2011, a massive earthquake and the resulting tsunami struck the Tohoku area in Japan, causing serious damages to TEPCO's Fukushima Daiichi nuclear plant and the release of a significant quantity of radionuclides into the surrounding environment. This accident underlined the necessity of establishing new and comprehensive scientific research for promoting safety in nuclear technology. With this aim, the Kyoto University Research Reactor Institute (KURRI) developed a new research program called the “KUR Research Program for Scientific Basis of Nuclear Safety” from this year. In this program, we are planning to hold an annual series of international symposiums along with many other research activities. The first in this series of symposiums, entitled “The International Symposium on Environmental Monitoring and Dose Estimation of Residents after Accident of TEPCO's Fukushima Daiichi Nuclear Power Station,” deals with the radiological effect of the March 2011 accident in Fukushima Daiichi NPP on the public. The purpose of this symposium is to collate data on environmental radioactivity anadiation dose in residents, discuss and verify these data, and clarify the actual situation of environmental contamination anesultant radiation exposed to the residents. We believe that an accurate estimation of the radiation dose is quite essential for planning for the healthy life and mental contentment of the residents, and we hope that many researchers who are studying the radiological effects of the accident will join us for these purposes. The environmental monitoring data are important for the dose assessment for residents. However, the monitoring data in the early stage are not sufficient for dose assessment, particularly near the NPP site, because of the confusion and blackout caused by the earthquake. However, many researchers and organizations in Japan and other countries have independently carried out radiation monitoring. We believe that the publication and

Light Water Reactor Sustainability Program, U.S. Efforts in Support of Examinations at Fukushima Daiichi-2017 Evaluations

Energy Technology Data Exchange (ETDEWEB)

Farmer, Mitchell T. [Argonne National Lab. (ANL), Argonne, IL (United States)

2017-08-01

Although the accident signatures from each unit at the Fukushima Daiichi Nuclear Power Station (NPS) [Daiichi] differ, much is not known about the end-state of core materials within these units. Some of this uncertainty can be attributed to a lack of information related to cooling system operation and cooling water injection. There is also uncertainty in our understanding of phenomena affecting: a) in-vessel core damage progression during severe accidents in boiling water reactors (BWRs), and b) accident progression after vessel failure (ex-vessel progression) for BWRs and Pressurized Water Reactors (PWRs). These uncertainties arise due to limited full scale prototypic data. Similar to what occurred after the accident at Three Mile Island Unit 2, these Daiichi units offer the international community a means to reduce such uncertainties by obtaining prototypic data from multiple full-scale BWR severe accidents. Information obtained from Daiichi is required to inform Decontamination and Decommissioning activities, improving the ability of the Tokyo Electric Power Company Holdings, Incorporated (TEPCO Holdings) to characterize potential hazards and to ensure the safety of workers involved with cleanup activities. This document, which has been updated to include FY2017 information, summarizes results from U.S. efforts to use information obtained by TEPCO Holdings to enhance the safety of existing and future nuclear power plant designs. This effort, which was initiated in 2014 by the Reactor Safety Technologies Pathway of the Department of Energy Office of Nuclear Energy Light Water Reactor (LWR) Sustainability Program, consists of a group of U.S. experts in LWR safety and plant operations that have identified examination needs and are evaluating TEPCO Holdings information from Daiichi that address these needs. Each year, annual reports include examples demonstrating that significant safety insights are being obtained in the areas of component performance, fission

Nuclear Crisis Communications: The Plan Worked. A Critique of NRC Communications in the Fukushima Daiichi Reactor Crisis - 12073

Energy Technology Data Exchange (ETDEWEB)

Brenner, Eliot; Harrington, Holly; Schmidt, Rebecca [U.S. Nuclear Regulatory Commission, Rockville, MD 20852 (United States)

2012-07-01

'Call the AV-Photo folks and get someone in here to shoot b-roll. We'll never be able to accommodate the network cameras and the only way I can get this to the media is to produce it ourselves'. Eliot Brenner, Director NRC Office of Public Affairs, March 12, 2011. For the past four years we have been speaking to audiences at Waste Management about communications issues. Last year, though we were kept from attending because of the federal budget crisis, our surrogates described to you the lessons the nuclear industry should draw from the BP Gulf oil spill crisis. Those remarks were delivered 11 days before the Fukushima Daiichi tragedy became the nuclear landmark of a generation - an industry changing event with worldwide ramifications, both in science and regulation and in communications. Eliot Brenner cut his teeth on crisis communication in the aviation industry where tragedy unfolds rapidly. He has been a speech-writer to three cabinet secretaries, spokesman for the Federal Aviation Administration and now spokesman for the Nuclear Regulatory Commission since 2004. Holly Harrington manages the NRC crisis response program and has 26 years federal public affairs experience, including eight years at the Federal Emergency Management Agency. Her crisis experience includes the 1989 Loma Prieta earthquake, numerous hurricanes and floods, Sept 11, and, now Fukushima Daiichi. Rebecca Schmidt is a veteran government relations professional whose decades in Washington include service with the House Armed Services Committee, the House Budget Committee and the Secretary of Defense. Collectively, the Offices of Public Affairs and Congressional Affairs conducted the largest outreach for the agency since Three Mile Island. We worked with the basic rule, described to Waste Management last year just 11 days before Fukushima - communicate early, often and clearly. The response - while not without its problems and lessons - went as smoothly as a chaotic event like

Updated synthesis of the knowledge about the impact on marine environment of the radioactive releases from Fukushima Dai-ichi damaged site - October 26, 2011

International Nuclear Information System (INIS)

2011-01-01

A strong radioactive contamination of the marine environment close to the damaged Fukushima Dai-ichi power plant has been observed since March 21. The high concentration of some nuclides ( 131 I, 137 Cs, 134 Cs, 136 Cs, 132 Te, 132 I) comes from three possible sources: the liquid effluents from the damaged site, the atmospheric fallouts, and the weathering of contaminated soils. This information note presents and comments the most recent informations gathered by the French institute of radiation protection and nuclear safety (IRSN) since the previous information note from July 11 and devoted to the same topic. It presents the estimation of the relative contribution of each contamination source and the evolution with time of the marine contamination. The mapping of 137 Cs concentrations in surface seawater allows to estimate the amount of total 137 Cs in the marine environment and its evolution with time. 137 Cs and 134 Cs concentrations were measured both in samples of surface coastal sediments and in river fishes and seafood products (mainly fishes and molluscs). Results are reported in graphs showing their evolution with time. (J.S.)

Introduction of new terms and lessons for radiological protection after Fukushima Dai-Ichi accident

International Nuclear Information System (INIS)

Singh, Vishwanath P.; Managanvi, S.S.; Bhat, H.R.

2012-01-01

The nuclear accidents in the world are very few among various types of operating facilities. However when an accident happened, we have learnt a lot to improve the philosophy, term, definitions, document preparation, equipment's requirement, supporting systems, awareness program and restriction etc. After Fukushima Dai-ichi we have learnt a lot, in this view this paper has been prepared to discuss for radiological protection aspects. Discussion: The probability of nuclear accidents is negligible but when happens, it opens new doors of lessons for radiological protection practices for occupational workers, emergency workers for damage control to prevent catastrophic situation/rescue to life saving actions and the member of the public. The Chernobyl and Three Mile Island accidents have provided a lot experiences for management of emergency situations, documentation, radiation emergency preparedness, emergency equipment's, concept of defense-in-depth, emergency planning zone (EPZ), accidental dose limits, estimation of source term and public dose, intervention levels, decision supporting system, remedial actions in public domain; decontamination of person, houses/building and land and etc. Recent Fukushima Dai-ichi accident in Japan was managed in appreciable manner but still new definitions and lessons for radiological protection have been emerged out. The present paper discusses difficulties w. r. t. the radiological aspects observed/faced by Japanese during nuclear crises. The accident introduced new terms as Natural Dose Rate Unit (NDRU), voluntary evacuation, deliberate evacuation area, restricted area and difference between evacuation zone and EPZ. The Fukushima accident has enforced worldwide regulators and operators to review the individual dose limit and amendment for raise in the dose limit during accident, availability of efficient/adequate quantities of personal dosimeter in public domain, collection arrangement of bulk amount of radioactive wastes

Estimation of average burnup of damaged fuels loaded in Fukushima Dai-ichi reactors by using the 134Cs/137Cs ratio method

International Nuclear Information System (INIS)

Endo, T.; Sato, S.; Yamamoto, A.

2012-01-01

Average burnup of damaged fuels loaded in Fukushima Dai-ichi reactors is estimated, using the 134 Cs/ 137 Cs ratio method for measured radioactivities of 134 Cs and 137 Cs in contaminated soils within the range of 100 km from the Fukushima Dai-ichi nuclear power plants. As a result, the measured 134 Cs/ 137 Cs ratio from the contaminated soil is 0.996±0.07 as of March 11, 2011. Based on the 134 Cs/ 137 Cs ratio method, the estimated burnup of damaged fuels is approximately 17.2±1.5 [GWd/tHM]. It is noted that the numerical results of various calculation codes (SRAC2006/PIJ, SCALE6.0/TRITON, and MVP-BURN) are almost the same evaluation values of 134 Cs/ 137 Cs ratio with same evaluated nuclear data library (ENDF-B/VII.0). The void fraction effect in depletion calculation has a major impact on 134 Cs/ 137 Cs ratio compared with the differences between JENDL-4.0 and ENDF-B/VII.0. (authors)

Post-processing activities after Chernobyl accident in Ukraine and lesson learned to the response Fukushima Dai-ichi accident

International Nuclear Information System (INIS)

Fujii, Yuzo

2012-01-01

After the accident of Chernobyl NPP no.4 1986, various activities including the construction of the shelter, prevention of the release of radioactive dust and liquid from the shelter, monitoring the condition of the damaged core, and disposal of radioactive waste have been implemented in the Chernobyl site for mitigating the nuclear and radioactive risks of damaged nuclear facilities, and the reducing radiation dose of working personnel. The construction of new shelter started for the decommissioning of the damaged unit no.4. facility. For reducing the radiation dose to the inhabitants from the contaminated land and feedstuff, the countermeasures including the set of the exclusive zone and permissible level of radionuclide in the foodstuff have been conducted for the countrywide. These activities include many valuable information about how to recover the condition of the site and maintain the social activities after the severe accident of NPP, and it would be important to learn the above activities in conducting the post-processing activities on the Fukushima-Daiichi accident successfully. (author)

14C levels in the vicinity of the Fukushima Dai-ichi Nuclear Power Plant prior to the 2011 accident

DEFF Research Database (Denmark)

Xu, Sheng; Cook, Gordon T.; Cresswell, Alan J.

2016-01-01

A 50-year-old Japanese cedar (Cryptomeria japonica) from Okuma, ∼1 km southwest of the Fukushima Dai-ichi Nuclear Power Plant, was cored and each annual ring was analysed for 14C. The 14C specific activity values varied from 330.4 Bq kg−1 C in the tree ring formed in 1971 to 231.2 Bq kg−1 C...... discharges from the reactors during their normal operations. In addition, the specific activities are positively correlated with the annual electricity generation values. The excess 14C specific activities were effective dose of ... ingestion pathway in the study location. The primary wind direction is east-southeast/southeast with a frequency of ∼30%, in comparison to ∼20% frequency for the direction of the site under study (north-northeast/northeast). This would tend to indicate a similar magnitude of additional effective dose...

Environmental behavior of the radionuclides released from the Fukushima Daiichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Yamazaki, Hideo

2014-01-01

The environmental behavior of radioactive nuclides released from the Fukushima Daiichi Nuclear Power Station (FDNPS) accident in eastern Japan was investigated. The radioactive pollution of environmental samples, including airborne dust, soil, sediment, fish, and other organisms was described. It was evaluated for environmental behavior and fate of the radioactive material from the spatial and temporal distribution of the radioactive nuclides. In Higashiosaka City about 600 km away from FDNPS, it begins to detect the radioactive nuclides in the airborne dust from 25th March 2011. Radioactive fission products 95 Zr- 95 Nb was detected on 18th April. The concentrations of 131 I, 134 Cs, and 137 Cs in the soil collected from Fukushima City were 126000, 14000, and 14200 Bq/kg on 19th March 2011 and 12800, 13200, and 13700 Bq/kg on 26th March 2011, respectively. The concentrations of 131 I, 134 Cs, and 137 Cs in the soil samples collected from March-June 2011 from study sites in metropolitan area and Kanto region ranged from nd to 91900, 59 to 16100, and 69 to 17600 Bq/kg, respectively. (Concentrations of 131 I were done decay correction to the value of 16th March) Radioactivities in fish samples collected from off FDNPS, Tokyo Bay, and Kejonuma Pond were measured. The radioactive contamination of forest ecosystem was also investigated. Two processes are involved in the radioactive contamination of the environment from the FDNPS accident. One is contamination by radioactive nuclides released from the hydrogen explosion. Leakage of contaminated cooling water to the ocean is in other important environmental pollution. We must continue carefully monitoring of radioactive nuclides in the environment. (author)

Accumulation of radioactive cesium released from Fukushima Daiichi Nuclear Power Plant in terrestrial cyanobacteria Nostoc commune.

Science.gov (United States)

Sasaki, Hideaki; Shirato, Susumu; Tahara, Tomoya; Sato, Kenji; Takenaka, Hiroyuki

2013-01-01

The Fukushima Daiichi Nuclear Power Plant accident released large amounts of radioactive substances into the environment and contaminated the soil of Tohoku and Kanto districts in Japan. Removal of radioactive material from the environment is an urgent problem, and soil purification using plants is being considered. In this study, we investigated the ability of 12 seed plant species and a cyanobacterium to accumulate radioactive material. The plants did not accumulate radioactive material at high levels, but high accumulation was observed in the terrestrial cyanobacterium Nostoc commune. In Nihonmatsu City, Fukushima Prefecture, N. commune accumulated 415,000 Bq/kg dry weight (134)Cs and 607,000 Bq kg(-1) dry weight (137)Cs. The concentration of cesium in N. commune tended to be high in areas where soil radioactivity was high. A cultivation experiment confirmed that N. commune absorbed radioactive cesium from polluted soil. These data demonstrated that radiological absorption using N. commune might be suitable for decontaminating polluted soil.

A knowledge on environmental radiation monitoring about the influence from Fukushima Dai-ichi Nuclear Power accident

International Nuclear Information System (INIS)

Yoshioka, Mitsuo; Terakawa, Kazuyoshi; Kasai, Toshihiro

2012-01-01

A large amount of radioactive substances were released in the atmosphere and contaminated a large area across Japan due to the accident at Fukushima Daiichi Nuclear Power Plant of Tokyo Electric Power Company triggered by Great East Japan Earthquake and tsunami on May 11th 2011. At Fukui University of Technology, monitoring of air radiation (gamma ray) and radiation in environmental samples in Fukui prefecture and some areas of Fukushima prefecture were conducted in order to study the influence of radiation and radioactivity on the citizens as well as the perception of this study results by the citizens. Also, in order to study the dependency of the radiation influence on the distance from the accident location, radiation monitoring of fallouts (air-borne dust, rainwater, sediment mud, and so on) was conducted. In this article, the knowledge obtained on environmental radiation monitoring was summarized and reported. Especially, slightly modified dose-level evaluation for internal exposure was reported. (S.K.)

Time changes in radiocesium concentration in aquatic systems affected by the Fukushima Daiichi NPP accident

Science.gov (United States)

Onda, Yuichi; Taniguchi, Keisuke; Kato, Hiroaki; Yoshimura, Kazuya; Wakiyama, Yoshifumi; Iwagami, Sho; Tsujimura, Maki; Sakaguchi, Aya; Yamamoto, Masatoshi

2015-04-01

Due to Fukushima Daiichi Nuclear Power Plant accident, radioactive materials including Cs-134 and Cs-137 were widely distributed in surrounded area. The radiocesiums have been transported in river networks. The monitoring started at 6 sites from June 2011. Subsequently, additional 24 monitoring sites were installed between October 2012 and January 2013. Flow and turbidity (for calculation of suspended sediment concentration) were measured at each site, while suspended sediments and river water were collected every one or half month to measure Cs-134 and Cs-137 activity concentrations by gamma spectrometry. Also detailed field monitoring has been condcuted in Yamakiya-district, Kawamata town, Fukushima prefecture. These monitoring includes, 1) Radiocesium wash-off from the runoff-erosion plot under different land use, 2) 2. Measurement of radiocesium transfer in forest environment, in association with hydrological pathways such as throughfall and overlandflow on hillslope, 3) Monitoring on radiocesium concentration in soil water, ground water, and spring water, 4)Monitoring of dissolved and particulate radiocesium concentration in river water, and stream water from the forested catchment, and 5)Measurement of radiocesium content in drain water and suspended sediment from paddy field. Our monitoring result demonstrated that the Cs-137 concentration in eroded sediment from the runoff-erosion plot has been almost constant for the past 3 years, however the Cs-137 concentration of suspended sediment from the forested catchment showed slight decrease through time. On the other hand, the suspended sediment from paddy field and those in river water from large catchments exhibited rapid decrease in Cs-137 concentration with time. The decreasing trend of Cs-137 concentration were fitted by the two-component exponential model, differences in decreasing rate of the model were compared and discussed among various land uses and catchment scales. Such analysis can provide

Electrical systems design applications on Japanese PWR plants in light of the Fukushima Daiichi Accident

International Nuclear Information System (INIS)

Nomoto, Tsutomu

2015-01-01

After the Fukushima Daiichi nuclear power plant (1F-NPP) accident (i.e. Station Blackout), several design enhancements have been incorporated or are under considering to Mitsubishi PWR plants' design of not only operational plants' design but also new plants' design. Especially, there are several important enhancements in the area of the electrical system design. In this presentation, design enhancements related to following electrical systems/equipment are introduced; - Offsite Power System; - Emergency Power Source; - Safety-related Battery; - Alternative AC Power Supply Systems. In addition, relevant design requirements/conditions which are or will be considered in Mitsubishi PWR plants are introduced. (authors)

Effects of the Fukushima Daiichi nuclear accident on goshawk reproduction

Science.gov (United States)

Murase, Kaori; Murase, Joe; Horie, Reiko; Endo, Koichi

2015-01-01

Although the influence of nuclear accidents on the reproduction of top predators has not been investigated, it is important that we identify the effects of such accidents because humans are also top predators. We conducted field observation for 22 years and analysed the reproductive performance of the goshawk (Accipiter gentilis fujiyamae), a top avian predator in the North Kanto area of Japan, before and after the accidents at the Fukushima Daiichi nuclear power plant that occurred in 2011. The reproductive performance declined markedly compared with the pre-accident years and progressively decreased for the three post-accident study years. Moreover, it was suggested that these declines were primarily caused by an increase in the air dose rate of radio-active contaminants measured under the nests caused by the nuclear accidents, rather than by other factors. We consider the trends in the changes of the reproductive success rates and suggest that internal exposure may play an important role in the reproductive performance of the goshawk, as well as external exposure. PMID:25802117

Analysis on Isolation Condenser Operation by Fukushima Daiichi Unit 1 Operators

International Nuclear Information System (INIS)

Kim, Man Cheol

2014-01-01

Fukushima Daiichi nuclear accident resulted in the core damage in three reactors and the release of considerable amount of radioactive material to the environment, not to mention significant social impact and anti-nuclear atmosphere all around the world. This paper provides a review of the findings related to shift operators' operation of the isolation condenser in Unit 1 to examine shift operators' response to the situation. Based on the review of the findings, a situation assessment model was developed to analyze shift operators' understanding on whether core cooling was successfully performed in Unit 1 through the operation of isolation condenser. It was found that lack of information could be one of the main causes for the failure in core cooling by the IC in Unit 1. It is also recommended that the differences in the mathematical model for the situation assessment and that of the real operator need to be further investigated

Analysis on Isolation Condenser Operation by Fukushima Daiichi Unit 1 Operators

Energy Technology Data Exchange (ETDEWEB)

Kim, Man Cheol [Chungang University, Seoul (Korea, Republic of)

2014-08-15

Fukushima Daiichi nuclear accident resulted in the core damage in three reactors and the release of considerable amount of radioactive material to the environment, not to mention significant social impact and anti-nuclear atmosphere all around the world. This paper provides a review of the findings related to shift operators' operation of the isolation condenser in Unit 1 to examine shift operators' response to the situation. Based on the review of the findings, a situation assessment model was developed to analyze shift operators' understanding on whether core cooling was successfully performed in Unit 1 through the operation of isolation condenser. It was found that lack of information could be one of the main causes for the failure in core cooling by the IC in Unit 1. It is also recommended that the differences in the mathematical model for the situation assessment and that of the real operator need to be further investigated.

Abbreviations [Annex to The Fukushima Daiichi Accident, Technical Volume 2/5

International Nuclear Information System (INIS)

2015-01-01

This annex is a list of abbreviations used in the publication The Fukushima Daiichi Accident, Technical Volume 2/5. The list includes the abbreviations for: • Agency for Natural Resources and Energy; • essential service water; • International Nuclear and Radiological Event Scale;• Integrated Regulatory Review Service; • Japan Atomic Energy Agency; • Japan Atomic Energy Commission; • Japan Power Engineering and Inspection Corp; • Japan Nuclear Energy Safety Organization; • low head safety injection; • low level radioactive waste; • Madras Atomic Power Station; • main control room; • Ministry of Economy, Trade and Industry; • Ministry of Education, Culture, Sports, Science and Technology; • Ministry of International Trade and Industry; • Ministry of Foreign Affairs; • Nuclear and Industrial Safety Agency; • Nuclear Power Corporation of India Limited; • nuclear power plant; • Nuclear Safety Commission; • Nuclear Power Engineering Corporation; • Nuclear Safety Technology Centre; • Onahama Port; • pressurized water reactor; • Science and Technology Agency; • Tokyo Electric Power Company

Assessment of radiation doses to the public in areas contaminated by the Fukushima Daiichi Nuclear Power Station accident

International Nuclear Information System (INIS)

Takahara, Shogo; Iijima, Masashi; Shimada, Kazumasa; Kimura, Masanori; Homma, Toshimitsu

2013-01-01

In the areas contaminated by radioactive materials due to the Fukushima Daiichi Nuclear Power Station accident, many residents are exposed to radiation through various exposure pathways. Dose assessment is important for providing appropriate protection to the people and clarifying the impact of the accident. The aim of this study is to provide preliminary results of the assessment of radiation doses received by the inhabitants of Fukushima Prefecture. To assess the doses realistically and comprehensively, a probabilistic approach was adopted using data that reflected realistic environmental trends and lifestyle habits in Fukushima Prefecture. In the first year after the contamination, the 95th percentile of the annual effective dose received by the inhabitants evacuated from the evacuation areas and the deliberate evacuation areas was mainly in the 1-10 mSv dose band. However, the 95th percentile of the dose received by some outdoor workers and inhabitants evacuated from highly contaminated areas was in the 10-50 mSv dose band. The doses due to external exposure to deposited radionuclides were the dominant exposure pathway, and their contributions were about 90% under prevailing contamination conditions in Fukushima Prefecture. In addition, 20%-30% of the lifetime effective dose was delivered during the first year after the contamination. (author)

Communication activity for residents to understand radiation after the accident of Fukushima Daiichi Nuclear Power Station

International Nuclear Information System (INIS)

Itabashi, Kiyoshi; Tagawa, Akihiro; Sugiyama, Kenji; Yamamoto, Tomoyo

2015-01-01

'Question-and-Answer Session on Radiation and Health' ('Kotaeru-kai' in Japanese) has started in July 2011 in Fukushima Prefecture, which was influenced by the accident of Fukushima Daiichi Nuclear Power Station following the Great East Japan Earthquake and Tsunami on 11 March 2011. The purpose of the Session is to have mainly parents and teachers (kindergartens, schools etc.) understand correctly about radiation and its influence on health. At the requests of the teachers in Fukushima Prefecture, about 4 staff members made a team, and visited Fukushima. The members of the team were selected from 500 JAEA staffs nominated beforehand. The members explained about radiation and its influence on health by using illustrations and metaphors. After the lecture, they answered the questions asked in advance at schools. Also they answered the questions asked in the Session. In the Session, the members placed much value on the communication with participants. Until the end of December 2014, the Question-and-Answer Sessions on Radiation and Health have been held 241 times for about twenty thousand participants. According to 7,613 participants' questionnaires, which were collected from July 2011 to the end of 2012, it seems that participants were able to understand well about radiation and its influence on health. Besides parents and teachers, some of the junior high schools requested to explain for students. JAEA will continue this communication activity in order to meet these expectations and requirements. (author)

Mobility of radioactive cesium in soil originated from the Fukushima Daiichi nuclear disaster. Application of extraction experiments

International Nuclear Information System (INIS)

Yoshikazu Kikawada; Takao Oi; Katsumi Hirose; Masaaki Hirose; Atsushi Tsukamoto; Ko Nakamachi; Teruyuki Honda; Hiroaki Takahashi

2015-01-01

Extraction experiments on soil radioactively contaminated by the Fukushima Daiichi Nuclear Power Plant accident were conducted by using a variety of extractants to acquire knowledge on the mobility of radioactive cesium in soil. The experimental results revealed that cesium is tightly bound with soil particles and that radioactive cesium newly deposited on soil due to the accident had apparently a higher mobility than stable cesium commonly existing in soil. The results suggested that radioactive cesium deposited on soil hardly migrates via aqueous processes, although chemical and mineralogical conditions of soil affect their mobility. (author)

Study on filling materials suitable for seawater piping trench closure work at Fukushima Daiichi Nuclear Power Plant

International Nuclear Information System (INIS)

Yanai, Shuji; Hibi, Yasuki; Nishikori, Kazumasa; Sato, Keita

2016-01-01

Highly contaminated water leaking from the reactor buildings and turbine buildings damaged by the 2011 Great East Japan Earthquake has accumulated in the seawater piping trenches of Fukushima Daiichi Nuclear Power Station Units 2, 3, and 4. In November 2014, work commenced to replace and remove this contaminated water by filling the trenches with filling materials, and this work was completed in December 2015. This paper summarizes the contents of this study on various filling materials, including special fillers with long-distance underwater flowability applied to the horizontal tunnel parts of the trenches. (author)

Accident of the Fukushima-Daiichi nuclear power station. Situation two years after the event - IRSN file

International Nuclear Information System (INIS)

2013-03-01

Two years after the Fukushima accident, this report proposes a review of the situation in Japan, and of the European and international actions aimed at preventing the occurrence of another nuclear accident and its radiological consequences. It is based on information available at the end of January or February 2013. After a recall of the situation in Japan and Europe in 2011 (recall of the accident, of the different simulation, calculation and information actions undertaken by the IRSN, launching of a program of additional safety assessments and of European stress tests), the report addresses the situation in Japan two years after the accident: evolution of the nuclear risk management governance, status of the Fukushima-Daiichi power station, health and environmental impact and management of the post-accidental phase, actions undertaken by the IRSN (dose assessment, cooperation in the field of severe accidents, participation to the Fukushima Dialogue). The next part details the contribution of the IRSN to the strengthening of safety and radiation protection at the international level (in relationship with international organizations: IAEA, UNSCEAR and WHO). Additional technical information is provided in appendix, as well as a report on the environmental impact of the accident, and a report on the post-accidental management of the accident

Philosophy of safety assurance after the Fukushima Daiichi accident. From views of experts

International Nuclear Information System (INIS)

Hisada, Tsukasa

2014-01-01

Knowledge incorporating meetings were held to exchange views of experts in order to learn respective safety concept and philosophy of safety assurance except nuclear area, how should be prepared for beyond expectation and what was needed to build social credibility, and how to upgrade safety measures of nuclear power station after the Fukushima Daiichi accident. Meeting had been held twice a year since FY2012 and two lecturers were invited at each meeting to give a lecture on the specified theme such as safety assurance in aviation area and chemical plants, and 'safety target of engineering system'. Common or different views on safety assurance between nuclear and other areas were identified, and risk concept and sincere attitude of explaining engineer were mentioned quite important for preparation for beyond expectation and building social credibility. (T. Tanaka)

Radiocesium distribution in bamboo shoots after the Fukushima nuclear accident.

Directory of Open Access Journals (Sweden)

Takumi Higaki

Full Text Available The distribution of radiocesium was examined in bamboo shoots, Phyllostachys pubescens, collected from 10 sites located some 41 to 1140 km from the Fukushima Daiichi nuclear power plant, Japan, in the Spring of 2012, 1 year after the Fukushima nuclear accident. Maximum activity concentrations for radiocesium ¹³⁴Cs and ¹³⁷Cs in the edible bamboo shoot parts, 41 km away from the Fukushima Daiichi plant, were in excess of 15.3 and 21.8 kBq/kg (dry weight basis; 1.34 and 1.92 kBq/kg, fresh weight, respectively. In the radiocesium-contaminated samples, the radiocesium activities were higher in the inner tip parts, including the upper edible parts and the apical culm sheath, than in the hardened culm sheath and underground basal parts. The radiocesium/potassium ratios also tended to be higher in the inner tip parts. The radiocesium activities increased with bamboo shoot length in another bamboo species, Phyllostachys bambusoides, suggesting that radiocesium accumulated in the inner tip parts during growth of the shoots.

Effective half-lives of 137Cs from persimmon tree tissue parts in Japan after Fukushima Dai-ichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Tagami, Keiko; Uchida, Shigeo

2015-01-01

To estimate the radiocesium decreasing rates from persimmon trees during a period of about 3 y following the accident at Tokyo Electric Power Company's Fukushima Dai-ichi Nuclear Power Plant (FDNPP), we conducted measurements of tree tissue parts collected in 2011–2013. The sampling was carried out in Chiba, 220 km south of FDNPP; radioactive fallouts discharged from FDNPP had mainly been observed in March–April 2011 on the sampling site. We measured 137 Cs concentrations in the tree tissue parts, i.e., fruits (flesh, skin and seeds), leaves and newly emerged branches, and then the effective half-lives (T eff ) of 137 Cs were calculated. Leaf samples were classified into two types by sampling months according to the growing stages, that is, immature (April–May) and mature (June–November) leaves. All these parts showed exponential declines in 137 Cs concentration with good adjusted contribution ratios of higher than ca. 0.7. The calculated T eff values from all tissue parts were similar with the average of 229 d (range: 216–243 d). From these results, we concluded that each tree tissue was representative for the calculation of T eff . For comparison to these observation results, open source food monitoring data from 2011 to 2013 including 137 Cs data for persimmon fruits collected in Fukushima Prefecture were used to calculate T eff for persimmon trees. Values of T eff were obtained for persimmon fruits grown in each local government area in Fukushima Prefecture and they ranged from 303 to 475 d. - Highlights: • 137 Cs decreased exponentially from persimmon trees in Chiba after the Fukushima accident. • The effective half-lives (T eff ) of 137 Cs from fruit, leaf and new branch tissues were similar. • The Food monitoring data were used to calculate effective half-lives for persimmon trees in Fukushima. • The average of T eff in Chiba was ca. 230 d while that in Fukushima was ca. 400 d

The groundwater problems and countermeasures of Fukushima Daiichi Nuclear Power Plant in 2014. In order to take off the protective clothing

International Nuclear Information System (INIS)

Marui, Atsunao

2014-01-01

Since the accident of Fukushima Daiichi Nuclear Power Station in March 2011, groundwater problem and its countermeasures have been reported in a variety of ways. Its information is hardly intended to accurately convey the purpose or circumstances, which generated a lot of misunderstanding. This paper rechecked the on-site geology and groundwater conditions. Based on the long-term plans of the government and Tokyo Electric Power Company toward the decommissioning, it mentions what the problem is and what kind of measures are being taken, and discusses the future challenges. It clarifies the features of the hydrogeology of the power plant region, while showing its pictures and geological cross-section view. Next, it describes the site where the contaminated water is stored and stored structure, the accumulated amount and leakage of the contaminated water, and explains the impact of groundwater problems on the decommissioning schedule. It also introduces groundwater measures, such as seaside impervious wall, land side impervious wall, fading, groundwater bypass, etc. (A.O.)

Spatiotemporal distribution of radioactive cesium released from Fukushima Daiichi Nuclear Power Station in the sediment of Tokyo Bay, Japan

International Nuclear Information System (INIS)

Nakagawa, Ryota; Ishida, Masanobu; Baba, Daisuke; Tanimoto, Satomi; Okamoto, Yuichi; Yamazaki, Hideo

2013-01-01

The spatial and temporal distribution of "1"3"4Cs and "1"3"7Cs released from Fukushima Daiichi Nuclear Power Station in the Tokyo Bay sediments were investigated. The total radioactivity of "1"3"4Cs and "1"3"7Cs detected in the Tokyo Bay sediment ranged from 240 to 870 Bq/kg-dry in the estuary of Arakawa River, but the activities detected in other sites were about 90 Bq/kg-dry or less. These results suggested that radioactive cesium, which precipitated to the ground, was carried to the river along with clay particles by rainfall and transported to the estuary. The vertical distribution of radioactive cesium showed that it invaded deeper than estimated based on the accumulation rate of the sediment. It was described that the vertical distribution of radioactive cesium was affected by physical mixing of sediments by tidal current, flood, and bioturbation of benthos. (author)

Study of treatment scenarios for fuel debris removed from Fukushima Daiichi NPS

International Nuclear Information System (INIS)

Washiya, Tadahiro; Yano, Kimihiko; Kaji, Naoya; Yamada, Seiya; Kamiya, Masayoshi

2015-01-01

On March 11, 2011, a severe nuclear accident occurred at Tokyo Electric Power Company (TEPCO)’s Fukushima Daiichi Nuclear Power Plant (hereinafter called as F1). After the accident, the Council for the Decommissioning was established, mainly by the government and TEPCO, and a road map for the F1 decommissioning was drawn up. In the road map, the fuel debris removal from the reactors is scheduled to launch around 2020. In this study, the characteristics and technological issues of each potential treatment scenario were extracted, and the scenarios were prioritized in advance of formal evaluations in the future. The preliminary evaluation results show that long term storage and direct disposal have more positive aspects in terms of economic efficiency and radioactive waste generation. On the other hand, stabilizing processing, aqueous processing, and pyrochemical processing have been estimated to have more disadvantages in such aspects. (author)

Knowledge Management Learned from Decommissioning and Environmental Remediation after an Unexpected Radiological Contamination Occurred at Fukushima Dai-ichi NPP Accident

International Nuclear Information System (INIS)

Inoue, T.

2016-01-01

Full text: The Fukushima Dai-ichi Nuclear Power Plant (NPP) Accident resulted in severe damage of cores in units 1 to 3, and subsequently entailed not only contamination of facility but also widely-spread radiological contamination in environment due to the release of radioactive nuclides. Decommissioning activities will require at least 30–40 years with various stages of operation, such as contaminated water treatment, decontamination of reactor buildings, retrieval of spent fuel (SF) from SF pools, inspection of primary containment vessel (PCV) and reactor pressure vessel (RPV), and retrieval and further management of damaged fuel and melted debris. Especially, a water injection for core cooling is a pressing issue to stabilize the melted debris, which leads to produce a large amount of contaminated water. Environmental remediation is a crucial issue to return a normal life for local residents. On-site cleaning and off-site remediation produce various kinds and enormous amount of contaminated material with low to high radioactivity. Knowledge management of on-site and off-site issues over generation are critical to achieve the cleaning and remediation requiring a couple of decades. In addition, knowledge obtained through a long term-operation should be shared globally. (author

Radiocesium concentrations in wild mushrooms collected in Kawauchi Village after the accident at the Fukushima Daiichi Nuclear Power Plant

Directory of Open Access Journals (Sweden)

Kanami Nakashima

2015-11-01

Full Text Available It is well known from the experience after the 1986 accident at the Chernobyl Nuclear Power Plant that radiocesium tends to concentrate in wild mushrooms. In this study, we collected wild mushrooms from the Kawauchi Village of Fukushima Prefecture, located within 30 km of the Fukushima Daiichi Nuclear Power Plant, and evaluated their radiocesium concentrations to estimate the risk of internal radiation exposure in local residents. We found that radioactive cesium exceeding 100 Bq/kg was detected in 125 of 154 mushrooms (81.2%. We calculated committed effective doses based on 6,278 g per year (age > 20 years, 17.2 g/day, the average intake of Japanese citizens, ranging from doses of 0.11–1.60 mSv, respectively. Although committed effective doses are limited even if residents eat contaminated foods several times, we believe that comprehensive risk-communication based on the results of the radiocesium measurements of food, water, and soil is necessary for the recovery of Fukushima after this nuclear disaster.

Birth Outcomes after the Fukushima Daiichi Nuclear Power Plant Disaster: A Long-Term Retrospective Study.

Science.gov (United States)

Leppold, Claire; Nomura, Shuhei; Sawano, Toyoaki; Ozaki, Akihiko; Tsubokura, Masaharu; Hill, Sarah; Kanazawa, Yukio; Anbe, Hiroshi

2017-05-19

Changes in population birth outcomes, including increases in low birthweight or preterm births, have been documented after natural and manmade disasters. However, information is limited following the 2011 Fukushima Daiichi Nuclear Power Plant Disaster. In this study, we assessed whether there were long-term changes in birth outcomes post-disaster, compared to pre-disaster data, and whether residential area and food purchasing patterns, as proxy measurements of evacuation and radiation-related anxiety, were associated with post-disaster birth outcomes. Maternal and perinatal data were retrospectively collected for all live singleton births at a public hospital, located 23 km from the power plant, from 2008 to 2015. Proportions of low birthweight (effects on maternal and perinatal health.

Accident at the Fukushima Dai-ichi Nuclear Power Stations of TEPCO —Outline & lessons learned—

Science.gov (United States)

TANAKA, Shun-ichi

2012-01-01

The severe accident that broke out at Fukushima Dai-ichi nuclear power stations on March 11, 2011, caused seemingly infinite damage to the daily life of residents. Serious and wide-spread contamination of the environment occurred due to radioactive materials discharged from nuclear power stations (NPSs). At the same time, many issues were highlighted concerning countermeasures to severe nuclear accidents. The accident is outlined, and lessons learned are extracted with respect to the safety of NPSs, as well as radiation protection of residents under the emergency involving the accident. The materials of the current paper are those released by governmental agencies, academic societies, interim reports of committees under the government, and others. PMID:23138450

Accident at the Fukushima Dai-ichi nuclear power stations of TEPCO. Outline and lessons learned

International Nuclear Information System (INIS)

Tanaka, Shun-ichi

2012-01-01

The severe accident that broke out at Fukushima Dai-ichi nuclear power stations on March 11, 2011, caused seemingly infinite damage to the daily life of residents. Serious and wide-spread contamination of the environment occurred due to radioactive materials discharged from nuclear power stations (NPSs). At the same time, many issues were highlighted concerning countermeasures to severe nuclear accidents. The accident is outlined, and lessons learned are extracted with respect to the safety of NPSs, as well as radiation protection of residents under the emergency involving the accident. The materials of the current paper are those released by governmental agencies, academic societies, interim reports of committees under the government, and others. (author)

Investigating plutonium contamination in marine sediments off Fukushima coast following the Fukushima Dai-ichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Bu Wenting; Guo Qiuju; Zheng, Jian; Aono, Tatsuo; Tagami, Keiko; Uchida, Shigeo; Zhang, Jing; Yamada, Masatoshi

2013-01-01

The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident has caused large amounts of anthropogenic radionuclides to be released into the atmosphere as well as directly discharged into the sea. To obtain the vertical distribution of Pu isotopes in marine sediments and to better assess the possible contamination from the FDNPP accident in the marine environment, activities of "2"3"9"+"2"4"0Pu and "2"4"1Pu, as well as the atom ratios of "2"4"0Pu/"2"3"9Pu and "2"4"1Pu/"2"3"9Pu, were investigated in a sediment core collected from the western North Pacific in July 2011. The observed vertical profile of "2"3"9"+"2"4"0Pu activities and "2"4"0Pu/"2"3"9Pu atom ratios showed no extra injection of Pu from the accident, indicating no immediate Pu contamination from the FDNPP accident in the marine sediments in the region investigated. (author)

Regional long-term model of radioactivity dispersion and fate in the Northwestern Pacific and adjacent seas: application to the Fukushima Dai-ichi accident.

Science.gov (United States)

Maderich, V; Bezhenar, R; Heling, R; de With, G; Jung, K T; Myoung, J G; Cho, Y-K; Qiao, F; Robertson, L

2014-05-01

The compartment model POSEIDON-R was modified and applied to the Northwestern Pacific and adjacent seas to simulate the transport and fate of radioactivity in the period 1945-2010, and to perform a radiological assessment on the releases of radioactivity due to the Fukushima Dai-ichi accident for the period 2011-2040. The model predicts the dispersion of radioactivity in the water column and in sediments, the transfer of radionuclides throughout the marine food web, and subsequent doses to humans due to the consumption of marine products. A generic predictive dynamic food-chain model is used instead of the biological concentration factor (BCF) approach. The radionuclide uptake model for fish has as a central feature the accumulation of radionuclides in the target tissue. The three layer structure of the water column makes it possible to describe the vertical structure of radioactivity in deep waters. In total 175 compartments cover the Northwestern Pacific, the East China and Yellow Seas and the East/Japan Sea. The model was validated from (137)Cs data for the period 1945-2010. Calculated concentrations of (137)Cs in water, bottom sediments and marine organisms in the coastal compartment, before and after the accident, are in close agreement with measurements from the Japanese agencies. The agreement for water is achieved when an additional continuous flux of 3.6 TBq y(-1) is used for underground leakage of contaminated water from the Fukushima Dai-ichi NPP, during the three years following the accident. The dynamic food web model predicts that due to the delay of the transfer throughout the food web, the concentration of (137)Cs for piscivorous fishes returns to background level only in 2016. For the year 2011, the calculated individual dose rate for Fukushima Prefecture due to consumption of fishery products is 3.6 μSv y(-1). Following the Fukushima Dai-ichi accident the collective dose due to ingestion of marine products for Japan increased in 2011 by a

New maintenance strategy of Tokyo Electric Power Company and Fukushima Dai-ichi Nuclear Power Plant for effective ageing management and safe long-term operation

International Nuclear Information System (INIS)

Inagaki, Takeyuki; Yamashita, Norimichi

2009-01-01

Fukushima Dai-ichi Nuclear Power Plant is the oldest among three nuclear power plants owned and operated by Tokyo Electric Power Company, which consists of six boiling water reactor units. The commercial operation of Unit 1 was commenced in 1971 (37 years old) and Unit 6 in 1978 (29 years old). Currently ageing degradations of systems, structures and components are managed through maintenance programs, component replacement/refurbishment programs and long-term maintenance plans. The long-term maintenance plans are established through ageing management component replacement/refurbishment programs reviews performed before the 30th year of operation and they are for safe and reliable operation after 30 years (long-term operation). However the past maintenance actions and past component replacement/refurbishment programs were not always proactive and past operational experience and maintenance practices suggest that effective/proactive ageing management programs be introduced in earlier stage of the plant operation. In this circumstance, Tokyo Electric Power Company and Fukushima Dai-ichi Nuclear Power Plant are setting up a new maintenance strategy that includes 1) improving the normal maintenance programs by using ageing degradation data, 2) effective use of information on internal/external operational experience and maintenance practices related to ageing, and 3) proactive component/equipment refurbishment programs during a refreshment outage for safe and reliable long-term operation. To accomplish the goal of this strategy, strengthening engineering capability of plant staff members is a crucial required for the plant. The objective of this paper is to briefly explain main results ageing management reviews, past and current significant ageing issues and management programs against them, and the new maintenance strategy established by Tokyo Electric Power Company and Fukushima Dai-ichi Nuclear Power Plant. (author)

A Bayesian Analysis of the Radioactive Releases of Fukushima

DEFF Research Database (Denmark)

Tomioka, Ryota; Mørup, Morten

2012-01-01

the types of nuclides and their levels of concentration from the recorded mixture of radiations to take necessary measures. We presently formulate a Bayesian generative model for the data available on radioactive releases from the Fukushima Daiichi disaster across Japan. From the sparsely sampled...... the Fukushima Daiichi plant we establish that the model is able to account for the data. We further demonstrate how the model extends to include all the available measurements recorded throughout Japan. The model can be considered a first attempt to apply Bayesian learning unsupervised in order to give a more......The Fukushima Daiichi disaster 11 March, 2011 is considered the largest nuclear accident since the 1986 Chernobyl disaster and has been rated at level 7 on the International Nuclear Event Scale. As different radioactive materials have different effects to human body, it is important to know...

Safety Research Opportunities Post-Fukushima. Initial Report of the Senior Expert Group

International Nuclear Information System (INIS)

Baek, Won-Pil; Yang, Joon-Eon; Ball, Joanne; Glowa, Glenn; Bisconti, Giulia; Peko, Damian; Bolshov, Leonid; Burgazzi, Luciano; De Rosa, Felice; Conde, Jose M.; Cook, Gary; Evrard, Jean-Michel; Jacquemain, Didier; Funaki, Kentaro; Uematsu, Mari Marianne; Miyoshi, Katsumasa; Tatematsu, Atsushi; Hirano, Masashi; Hoshi, Harutaka; Kawaragi, Chie; Kobayashi, Youko; Sakamoto, Kazunobu; Journeau, Christophe; Kim, Han-Chul; Klein-Hessling, Walter; Sonnenkalb, Martin; Koganeya, Toshiyuki; White, Andrew; ); Lind, Terttaliisa; Zimmermann, Martin; Lindholm, Ilona; Castelo Lopez, Carlos; Nagase, Fumihisa; Washiya, Tadahiro; Oima, Hirofumi; Okada, Hiro; Richards, Stuart; West, Steven; Sandberg, Nils; Suzuki, Shunichi; Vitanza, Carlo; Yamanaka, Yasunori

2017-02-01

One of the imperatives following the accident at the Fukushima Daiichi nuclear power station is for the nuclear science and industry communities to ensure that knowledge gaps in nuclear safety are identified and that research programs to address these gaps are being instituted. In recognition of broad international interest in additional information that could be gained from post-accident examinations related to Fukushima Daiichi, Japan recommended to the Committee on the Safety of Nuclear Installations (CSNI) in June 2013 that a process be developed to identify and follow up on opportunities to address safety research gaps. Consequently, a Senior Expert Group (SEG) on Safety Research Opportunities post-Fukushima (SAREF) was formed. The members of the group are senior technical experts from technical support organisations, nuclear regulatory authorities and Japanese organisations responsible for planning and execution of Fukushima Daiichi decommissioning. The domain of interest for the group is activities that address safety research knowledge gaps and also the needs of Fukushima Daiichi decommissioning. SEG on SAREF identified areas where these two interests intersect or overlap, and activities that could be undertaken to generate information of common benefit. The group's output is documented in this report; Chapter 2 describes the current status of the damaged units at Fukushima Daiichi NPS; Chapter 3 summarises safety research areas of common interest; Chapter 4 summarises the safety research activities recommended as short-term projects; Chapter 5 summarises those as long-term considerations; Chapter 6 supplies conclusions and recommendations. The appendix contains detailed information compiled by the SEG members on all safety research areas of interest

Estimation of Te-132 distribution in Fukushima Prefecture at the early stage of the Fukushima Daiichi Nuclear Power Plant reactor failures.

Science.gov (United States)

Tagami, Keiko; Uchida, Shigeo; Ishii, Nobuyoshi; Zheng, Jian

2013-05-21

Tellurium-132 ((132)Te, half-life: 3.2 d) has been assessed as the radionuclide with the third largest release from the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011; thus it would have made some dose contribution during the early stage of the reactor failures. The available data for (132)Te are, however, limited. In this study, available reported values of other isotopes of Te were compiled to estimate (132)Te concentration (in MBq m(-2)). It was found that (132)Te and (129m)Te (half-life: 33.6 d) concentrations were well correlated (R = 0.99, p < 0.001) by t test. Thus, (132)Te concentrations on March 11, 2011 were estimated from (129m)Te using the concentration conversion factor ((132)Te /(129m)Te) of 14.5. It was also found that since deposited (129m)Te was well retained in the soil, the data collected in March-May of 2011 were applicable to (132)Te estimation. It was possible to obtain the first (132)Te concentration contour map for the eastern part of Fukushima Prefecture, including data from within the 20-km exclusion zone around the FDNPP, using these newly available estimated (132)Te data sets.

INITIAL AND PRESENT SITUATION OF FOOD CONTAMINATION IN JAPAN AFTER THE ACCIDENT AT THE FUKUSHIMA DAI-ICHI NUCLEAR POWER PLANT.

Science.gov (United States)

Aono, Tatsuo; Yoshida, Satoshi; Akashi, Makoto

2016-09-01

The accident at the Fukushima Dai-ichi Nuclear Power Plant (NPP) in March 2011 affected not only the terrestrial environment of Fukushima prefecture and the surrounding area, but also the marine area facing the NPP. Our present study is focused on the concentrations of radionuclides in agricultural products of Fukushima and sea-foods collected off Fukushima after the accident. The regulation value for radiocesium in vegetables, meat and fish was revised from 500 Bq/kg-wet to 100 Bq/kg-wet on 1 April 2012. The overall activity of radiocesium in these products was found to be within the limit of tolerance in respect to Japanese and also international regulations, but there is still radiocesium found at activities greater than this level in edible wild plants, wild mushrooms and game such as boar meat. Although the activities of radionuclides exceeding the regulatory limits were not detected in marine products collected off Fukushima after April 2015, the commercial marine fishery has not received approval in the affected areas except for certain species. We learned from the Fukushima accident that long-term kinetic studies of radionuclides in terrestrial and marine environments is extremely important for prevention of internal contamination, since contamination with radionuclides occurs via the food chain in the environment. © World Health Organisation 2016. All rights reserved. The World Health Organization has granted Oxford University Press permission for the reproduction of this article.

Evaluation of short- and long-term fission product sources at the Fukushima Daiichi NPP

International Nuclear Information System (INIS)

Uchida, Shunsuke; Naitoh, Masanori; Suzuki, Hiroaki; Okada, Hidetoshi; Pellegrini, Marco; Achilli, Andrea; Hanamoto, Yukio; Sasaki, Hiroaki

2014-01-01

Research on fission product (FP) behaviors used to be one of the most important subjects in water chemistry but it is not done nowadays as a consequence of the increased integrity of nuclear fuels and the minimization of FP release into the environment. Evaluation of FP release into the environment is still one of the key issues for severe accident analysis, though. Although there have been a long quiet period in nuclear safety research, how to detect initiation of severe accidents, how to prevent them and how to mitigate them are still important subjects for nuclear engineering, and how to control the severe accidents after their occurrence, especially how to control FP release into the environment, has seldom been discussed in the water chemistry group recently. The paper is intended to address the issue of fewer activities for FP studies. FP sources are divided into two categories, short- and long-term FP sources. Short-term FP source can be evaluated based on the measured data obtained from monitoring posts (MPs), which give us clear evidence on the importance of radioactive iodine and cesium releases into the environment. It used to be considered that during primary containment vessel (PCV) venting, release of each element, e.g., iodine and cesium, was determined by the suppression pool scrubbing efficiency and most of the cesium would likely be removed in the pool due to its large scrubbing efficiency. But as a result of analyzing the MP data at early stage of the Fukushima Daiichi nuclear power plant (NPP) accident, it was confirmed that the releases of both elements were in proportion to their inventories in the reactors and their scrubbing efficiencies were almost the same. The scrubbing efficiency which increased with the pool water temperature became almost the same for iodine and cesium around the pool water boiling temperature. As a result of the mass balance analysis for FPs in the contaminated water accumulated in the Fukushima Daiichi plant site, it

Industrial Safety and Utopia: Insights from the Fukushima Daiichi Accident.

Science.gov (United States)

Travadel, Sébastien; Guarnieri, Franck; Portelli, Aurélien

2018-01-01

Feedback from industrial accidents is provided by various state or even international, institutions, and lessons learned can be controversial. However, there has been little research into organizational learning at the international level. This article helps to fill the gap through an in-depth review of official reports of the Fukushima Daiichi accident published shortly after the event. We present a new method to analyze the arguments contained in these voluminous documents. Taking an intertextual perspective, the method focuses on the accident narratives, their rationale, and links between "facts," "causes," and "recommendations." The aim is to evaluate how the findings of the various reports are consistent with (or contradict) "institutionalized knowledge," and identify the social representations that underpin them. We find that although the scientific controversy surrounding the results of the various inquiries reflects different ethical perspectives, they are integrated into the same utopian ideal. The involvement of multiple actors in this controversy raises questions about the public construction of epistemic authority, and we highlight the special status given to the International Atomic Energy Agency in this regard. © 2017 The Authors Risk Analysis published by Wiley Periodicals, Inc. on behalf of Society for Risk Analysis.

Analysis of core melt accident in Fukushima Daiichi-Unit 1 nuclear reactor

International Nuclear Information System (INIS)

Tanabe, Fumiya

2011-01-01

In order to obtain a profound understanding of the serious situation in Unit 1 and Unit 2/3 reactors of Fukushima Daiichi Nuclear Power Station (hereafter abbreviated as 1F1 and 1F2/3, respectively), which was directly caused by tsunami due to a huge earthquake on 11 March 2011, analyses of severe core damage are performed. In the present report, the analysis method and 1F1 analysis are described. The analysis is essentially based on the total energy balance in the core. In the analysis, the total energy vs. temperature curve is developed for each reactor, which is based on the estimated core materials inventory and material property data. Temperature and melt fraction are estimated by comparing the total energy curve with the total stored energy in the core material. The heat source is the decay heat of fission products and actinides together with reaction heat from the zirconium steam reaction. (author)

An outline of the interim report of the investigation committee on the accident at Fukushima Nuclear Power Stations

International Nuclear Information System (INIS)

Yoshioka, Hitoshi

2012-01-01

Interim report of the Investigation Committee of the Accident at Fukushima Nuclear Power Stations (NPSs) was published in December 26, 2011. The Japanese cabinet approved ten committee members including the author in May 2011. The committee interviewed more than 400 people over a total of 900 hours of hearings with about 40 staffs consisting of administrative team and three investigation teams of social system, root causes of the accident and countermeasures to prevent damage expansion of the accident. Interim report concluded 'the accident at Fukushima NPSs was caused by failures of every provision against reactor severe accident'. The failures appeared on (1) function of supervisory system for emergency response, (2) Fukushima Daiichi NPSs on-site disaster response especially related with operation of isolation condenser of unit 1 and high-pressure coolant injection system of unit 3, (3) Fukushima Daiichi NPSs off-site disaster response such the government failed to make use of data on the radioactive plumes released from the plant for evacuations, and (4) preparedness against tsunami and severe accident management. Possible worst or best simulation cases were also discussed. With no human support available on-site, workers might not have been able to prevent the meltdowns. Final report was due at the end of July 2012. (T. Tanaka)

Review of health issues of workers engaged in operations related to the accident at the Fukushima Daiichi Nuclear Power Plant.

Science.gov (United States)

Hiraoka, Koh; Tateishi, Seiichiro; Mori, Koji

2015-01-01

The aim of this review was to summarize the lessons learned from the experience in protecting the health of workers engaged in operations following the accident at the Fukushima Daiichi Nuclear Power Plant (NPP). We reviewed all types of scientific papers examining workers' health found in Medline and Web of Sciences as well as some official reports published by the Ministry of Health, Labour and Welfare of Japan and other governmental institutes. The papers and reports were classified into those investigating workers at the Fukushima Daiichi and Daini NPPs, workers engaged in decontamination operations in designated areas, and other workers. Regarding workers at the NPPs, many efforts were made to establish an emergency-care and occupational health system. Risk management efforts were undertaken for radiation exposure, heat stress, psychological stress, outbreak of infectious diseases, and fitness for work. Only a few reports dealt with decontamination workers and others; however, the health management of these workers was clearly weaker than that for workers at the NPPs. Many lessons can be learned from what occurred. That knowledge can be applied to ongoing decommissioning work and to future disasters. In addition, it is necessary to study the long-term health effects of radiation exposure and to accumulate data about the health of workers engaged in decontamination work and other areas.

Spatial distribution of Iodine-129 in surface soil around the Fukushima Daiichi Nuclear Power Plant

International Nuclear Information System (INIS)

Miyake, Yasuto; Tagi, Kazuhiro; Matsuzaki, Hiroyuki; Fujiwara, Takeshi; Saito, Takumi; Yamagata, Takeyasu; Tsuchiya, Yoko; Nakano, Chuichiro; Honda, Maki

2011-01-01

Due to the accident at the Fukushima Daiichi nuclear power plant, which was caused by the Great East Japan Earthquake, a lot of radioactive materials were released into the environment. Among them, Iodine-131, which has a short half-life of 8 days, is thought to be hardly detected after the accident is concluded. It is very important to research how leaked out Iodine-131 was diffused in order to estimate the health impact of radiation at the time of the accident. On the other hand, Iodine-129, which was leaked out and was thought to act chemically-identically as Iodine-131, has an extremely long half-life of 15.7 million years and we are able to measure it equally after the accident. By following the trail of Iodine-129, it is considered to estimate the distribution of Iodine-131. To do this, at first, it is essential to measure simultaneously Iodine-131 and Iodine-129 in the same sample picked from near-the Fukushima Daiichi nuclear power plant and examine the relation between them (for example, the isotopic ratio of Iodine derived from the nuclear power plant (I-129/I-131)). At this study, we measured Iodine-129 in surface soil within 60 kilometers of the Fukushima Daiichi nuclear power plant, which was picked by research team of Nuclear Engineering Research Laboratory, Faculty of Engineering, the University of Tokyo. We discuss Iodine-129 derived from the nuclear power plant by considering the concentration range, the relation of a distance or a direction from the nuclear power plant, and the relation between I-129 and other radioactive nuclides (Cs-134, Cs-137, I-131). Since Iodine-129, which had been leaked out from the nuclear fuel reprocessing plant in Europe, was already transferred to Japan by way of the atmospheric transportation before the accident, it is important to distinguish between Iodine-129 from this accident and from the reprocessing plant. Then, we want to obtain the I-129/I-131 ratio originating in the accident precisely and discuss the

Sociological aspects of 3.11 Fukushima Daiichi Accident aftermath and the Genshiryoku-mura (nuclear village, or pro-nuclear concession sector)

Energy Technology Data Exchange (ETDEWEB)

Sawada, T., E-mail: tetsuo@nr.titech.ac.jp [Tokyo Inst. of Technology, Research Laboratory for Nuclear Reactors, Meguro-ku, Tokyo (Japan)

2014-07-01

In the 3.11 Fukushima Daiichi Accident aftermath, information contamination induced societal confusion that led to unnecessarily grave fear among the public. The origins and development of the information contamination, and the labeling of Goyo-gakusha and Genshiryoku-mura were phenomenologically analyzed. The historical background to, and reasons for emergence of Goyo-gakusha's were examined by using an axiological approach. The analyses and examination have clarified a typical case of the origins to formation of Genshiryoku-mura. (author)

The Fukushima Daiichi Nuclear Power Plant Accident: OECD/NEA Nuclear Safety Response and Lessons Learnt

International Nuclear Information System (INIS)

2013-01-01

Following the March 2011 accident at the Fukushima Daiichi nuclear power plant, all NEA member countries took early action to ensure and confirm the continued safety of their nuclear power plants and the protection of the public. After these preliminary safety reviews, all countries with nuclear facilities carried out comprehensive safety reviews, often referred to as 'stress tests', which reassessed safety margins of nuclear facilities with a primary focus on challenges related to conditions experienced at the Fukushima Daiichi nuclear power plant, for example extreme external events and the loss of safety functions, or capabilities to cope with severe accidents. As appropriate, improvements are being made to safety and emergency response systems to ensure that nuclear power plants are capable of withstanding events that lead to loss of electrical power and/or cooling capability. In the weeks following the accident, the NEA immediately began establishing expert groups in the nuclear safety and radiological protection areas, as well as contributing to information exchange with the Japanese authorities and other international organisations. It promptly provided a forum for high-level decision makers and regulators within the G8-G20 frameworks. The NEA actions taken at the international level in response to the accident have been carried out primarily by the three NEA standing technical committees concerned with nuclear and radiation safety issues - the Committee on Nuclear Regulatory Activities (CNRA), the Committee on the Safety of Nuclear Installations (CSNI) and the Committee on Radiation Protection and Public Health (CRPPH) - under the leadership of the CNRA. More than two years following the accident, the NEA continues to assist the Japanese authorities in dealing with their nuclear safety and recovery efforts as well as to facilitate international co-operation on nuclear safety and radiological protection matters. It is strongly supporting the establishment of

Safety-critical human factors issues derived from analysis of the TEPCO Fukushima Daiichi accident investigation reports

International Nuclear Information System (INIS)

Sakuda, Hiroshi; Takeuchi, Michiru

2013-01-01

The Fukushima Daiichi nuclear power plant accident on March 11, 2011 had a large impact both in and outside Japan, and is not yet concluded. After Tokyo Electric Power Co.'s (TEPCO's) Fukushima accident, electric power suppliers have taken measures to respond in the event that the same state of emergency occurs - deploying mobile generators, temporary pumps and hoses, and training employees in the use of this equipment. However, it is not only the “hard” problems including the design of equipment, but the “soft” problems such as organization and safety culture that have been highlighted as key contributors in this accident. Although a number of organizations have undertaken factor analysis of the accident and proposed issues to be reviewed and measures to be taken, a systematic overview about electric power suppliers' organization and safety culture has not yet been undertaken. This study is based on three major reports: the report by the national Diet of Japan Fukushima Nuclear Accident Independent Investigation Commission (the Diet report), the report by the Investigation Committee on the Accident at Fukushima Nuclear Power Stations of Tokyo Electric Power Company (Government report), and the report by the non-government committee supported by the Rebuild Japan Initiative Foundation (Non-government report). From these reports, the sections relevant to electric power suppliers' organization and safety culture were extracted. These sections were arranged to correspond with the prerequisites for the ideal organization, and 30 issues to be reviewed by electric power suppliers were extracted using brainstorming methods. It is expected that the identified issues will become a reference for every organization concerned to work on preventive measures hereafter. (author)

Safety goals for seismic and tsunami risks: Lessons learned from the Fukushima Daiichi disaster

Energy Technology Data Exchange (ETDEWEB)

Saji, Genn, E-mail: sajig@bd5.so-net.ne.jp

2014-12-15

Highlights: • Reviewed why the Fukushima disaster was not anticipated among seismologists. • Reviewed Fukushima Daiichi's preparedness against the earthquake and tsunami. • There was a large “cliff edge” in radiological consequences from the design basis tsunami. • By including earthquakes as an “external event” resulted in insufficient “defense in depths”. • Proposes a new probabilistic seismic and tsunami safety goal be developed. - Abstract: This paper first reviews why the potential occurrence of the Tohoku-oki earthquake with momentum magnitude M{sub w} of 9.0 earthquake was not anticipated by Japanese seismologists, and to clarify our limitations in predicting rare but severe earthquakes at our current knowledge in the field of geosciences. Although there was a large volume of historical records related to earthquakes and tsunamis, generally this data infer high plate coupling in regions where earthquakes were known to have already occurred, with only partial or even no coupling from the Japan Trench to a point approximately midway between the trench and the coastline—precisely the region where the 2011 Tohoku-Oki earthquake occurred. This phenomenon has been explained as a “silent earthquake” or a fault creep as observed at the San Andreas Faults in the US. Considering the large uncertainties in seismic events, nuclear power plants should be conservatively designed with adequate safety margins. TEPCO's preparedness against seismic and tsunami hazards were reviewed in order to clarify why the established safety margin was not sufficient during the Fukushima Daiichi. It was found that the plant incorporated the necessary safety margins against seismic oscillation however, there was a large “cliff edge” in which the radiological consequences surged by several orders of magnitude from the design basis tsunami. Since the tsunami's height was greater than the ground level of the turbine hall, a large amount of the

Safety goals for seismic and tsunami risks: Lessons learned from the Fukushima Daiichi disaster

International Nuclear Information System (INIS)

Saji, Genn

2014-01-01

Highlights: • Reviewed why the Fukushima disaster was not anticipated among seismologists. • Reviewed Fukushima Daiichi's preparedness against the earthquake and tsunami. • There was a large “cliff edge” in radiological consequences from the design basis tsunami. • By including earthquakes as an “external event” resulted in insufficient “defense in depths”. • Proposes a new probabilistic seismic and tsunami safety goal be developed. - Abstract: This paper first reviews why the potential occurrence of the Tohoku-oki earthquake with momentum magnitude M w of 9.0 earthquake was not anticipated by Japanese seismologists, and to clarify our limitations in predicting rare but severe earthquakes at our current knowledge in the field of geosciences. Although there was a large volume of historical records related to earthquakes and tsunamis, generally this data infer high plate coupling in regions where earthquakes were known to have already occurred, with only partial or even no coupling from the Japan Trench to a point approximately midway between the trench and the coastline—precisely the region where the 2011 Tohoku-Oki earthquake occurred. This phenomenon has been explained as a “silent earthquake” or a fault creep as observed at the San Andreas Faults in the US. Considering the large uncertainties in seismic events, nuclear power plants should be conservatively designed with adequate safety margins. TEPCO's preparedness against seismic and tsunami hazards were reviewed in order to clarify why the established safety margin was not sufficient during the Fukushima Daiichi. It was found that the plant incorporated the necessary safety margins against seismic oscillation however, there was a large “cliff edge” in which the radiological consequences surged by several orders of magnitude from the design basis tsunami. Since the tsunami's height was greater than the ground level of the turbine hall, a large amount of the tsunami

Five Years after the Fukushima Daiichi Accident: Nuclear Safety Improvements and Lessons Learnt

International Nuclear Information System (INIS)

Magwood, William D. IV; Niel, Jean-Christophe; Fuketa, Toyoshi; Sheron, Brian; Boyd, Michael; McGarry, Ann; Dussart-Desart, Roland; Reig, Javier; Hah, Yeonhee; Nieh, Ho; Vasquez-Maignan, Ximena; Salgado, Nancy; White, Andrew; Lazo, Edward; Creswell, Len; Leeds, Eric; Gannon-Picot, Cynthia; Griffiths, Janice

2016-01-01

Countries around the world continue to implement safety improvements and corrective actions based on lessons learnt from the 11 March 2011 accident at the Fukushima Daiichi nuclear power plant. This report provides a high-level summary and update on these activities, and outlines further lessons learnt and challenges identified for future consideration. It focuses on actions taken by NEA committees and NEA member countries, and as such is complementary to reports produced by other international organisations. It is in a spirit of openness and transparency that NEA member countries share this information to illustrate that appropriate actions are being taken to maintain and enhance the level of safety at their nuclear facilities. Nuclear power plants are safer today because of these actions. High-priority follow-on items identified by NEA committees are provided to assist countries in continuously benchmarking and improving their nuclear safety practices. (authors)

Relationship between particle size and radiocesium in fluvial suspended sediment related to the Fukushima Daiichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Kazuya Tanaka

2014-01-01

We collected fluvial suspended sediments in Fukushima after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident and analyzed the 137 Cs concentration in bulk and size-fractioned samples to investigate the particle-size-dependent distribution of radiocesium. The 137 Cs concentration in bulk suspended sediments decreased from August to December 2011, possibly reflecting a decrease of radiocesium concentration in its source materials. Smaller particles had higher radiocesium concentrations, reflecting larger specific surface areas. Silt- and sand-size fractions occupied more than 95 % of the total 137 Cs in the suspended sediments. The contribution of clay-size fractions, which had the highest 137 Cs concentration, was quite small because of their low frequency. A line of the data showed that the particle size distribution of radiocesium was essential to evaluate the migration and distribution of radiocesium in river systems where radiocesium is mainly present as particulate form after the FDNPP accident. (author)

An overview of current knowledge concerning the health and environmental consequences of the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident.

Science.gov (United States)

Aliyu, Abubakar Sadiq; Evangeliou, Nikolaos; Mousseau, Timothy Alexander; Wu, Junwen; Ramli, Ahmad Termizi

2015-12-01

Since 2011, the scientific community has worked to identify the exact transport and deposition patterns of radionuclides released from the accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in Japan. Nevertheless, there still remain many unknowns concerning the health and environmental impacts of these radionuclides. The present paper reviews the current understanding of the FDNPP accident with respect to interactions of the released radionuclides with the environment and impacts on human and non-human biota. Here, we scrutinize existing literature and combine and interpret observations and modeling assessments derived after Fukushima. Finally, we discuss the behavior and applications of radionuclides that might be used as tracers of environmental processes. This review focuses on (137)Cs and (131)I releases derived from Fukushima. Published estimates suggest total release amounts of 12-36.7PBq of (137)Cs and 150-160PBq of (131)I. Maximum estimated human mortality due to the Fukushima nuclear accident is 10,000 (due to all causes) and the maximum estimates for lifetime cancer mortality and morbidity are 1500 and 1800, respectively. Studies of plants and animals in the forests of Fukushima have recorded a range of physiological, developmental, morphological, and behavioral consequences of exposure to radioactivity. Some of the effects observed in the exposed populations include the following: hematological aberrations in Fukushima monkeys; genetic, developmental and morphological aberrations in a butterfly; declines in abundances of birds, butterflies and cicadas; aberrant growth forms in trees; and morphological abnormalities in aphids. These findings are discussed from the perspective of conservation biology. Copyright © 2015 Elsevier Ltd. All rights reserved.

Factors associated with nurses' intention to leave their jobs after the Fukushima Daiichi Nuclear Power plant accident.

Directory of Open Access Journals (Sweden)

Yoshinobu Sato

Full Text Available We conducted a survey among nurses who were working at the Fukushima Medical University Hospital at the time of the Fukushima Daiichi Nuclear Power Plant accident to clarify the factors associated with their intention to leave their jobs during the radiation emergency. We asked 345 nurses (17 men and 328 women about their intention to leave their jobs after the accident. We also asked about relevant factors including the participants' demographic factors, living situation, working status, and knowledge of radiation health effects. We found that living with preschoolers (OR = 1.87, 95%CI: 1.02-3.44, p = 0.042, anxiety about life in Fukushima City after the accident (OR = 5.55, 95%CI: 1.18-26.13, p = 0.030, consideration of evacuation from Fukushima after the accident (OR = 2.42, 95%CI: 1.45-4.06, p = 0.001, consideration of the possible radiation health effects in children (OR = 1.90, 95%CI: 1.02-3.44, p = 0.042, and anxiety about relationships with colleagues in the hospital after the accident (OR = 3.23, p = 0.001 were independently associated with the nurses' intention to leave their jobs after the accident. On the other hand, the percentage of nurses with knowledge on radiation health effects was relatively low among those who had the intention to leave the job and among those who did not have the intention to leave the job after the accident, with no significant differences between the two groups. Our results suggest the need for an education program for nurses regarding radiation health effects.

Fission products in National Atmospheric Deposition Program—Wet deposition samples prior to and following the Fukushima Dai-Ichi Nuclear Power Plant incident, March 8?April 5, 2011

Science.gov (United States)

Wetherbee, Gregory A.; Debey, Timothy M.; Nilles, Mark A.; Lehmann, Christopher M.B.; Gay, David A.

2012-01-01

Radioactive isotopes I-131, Cs-134, or Cs-137, products of uranium fission, were measured at approximately 20 percent of 167 sampled National Atmospheric Deposition Program monitoring sites in North America (primarily in the contiguous United States and Alaska) after the Fukushima Dai-Ichi Nuclear Power Plant incident on March 12, 2011. Samples from the National Atmospheric Deposition Program were analyzed for the period of March 8-April 5, 2011. Calculated 1- or 2-week radionuclide deposition fluxes at 35 sites from Alaska to Vermont ranged from 0.47 to 5,100 Becquerels per square meter during the sampling period of March 15-April 5, 2011. No fission-product isotopes were measured in National Atmospheric Deposition Program samples obtained during March 8-15, 2011, prior to the arrival of contaminated air in North America.

Input and output budgets of radiocesium concerning the forest floor in the mountain forest of Fukushima released from the TEPCO's Fukushima Dai-ichi nuclear power plant accident

International Nuclear Information System (INIS)

Niizato, Tadafumi; Abe, Hironobu; Mitachi, Katsuaki; Sasaki, Yoshito; Ishii, Yasuo; Watanabe, Takayoshi

2016-01-01

Estimations of radiocesium input and output concerning the forest floor within a mountain forest region have been conducted in the north and central part of the Abukuma Mountains of Fukushima, northeast Japan, after a 2–3 year period following the TEPCO Fukushima Dai-ichi nuclear power plant accident. The radiocesium input and output associated with surface washoff, throughfall, stemflow, and litterfall processes at experimental plots installed on the forest floor of evergreen Japanese cedars and deciduous Konara oaks have been monitored. Despite the high output potential in the mountainous forest of Fukushima, the results at both monitoring locations show the radiocesium input to be 4–50 times higher than the output during the summer monsoon in Fukushima. These results indicate that the radiocesium tends to be preserved in the forest ecosystem due to extremely low output ratios (0.05%–0.19%). Thus, the associated fluxes throughout the circulation process are key issues for the projecting the environmental fate of the radiocesium levels, along with the subsequent reconstruction of life emphasized within the setting. - Highlights: • Input and output budgets of radiocesium in the mountainous forest of Fukushima were investigated in 2013 and 2014. • "1"3"7Cs outputs were 4–50 times higher than the "1"3"7Cs outputs during the monsoons. • The proportion of "1"3"7Cs output to radiocesium inventories was in the range of 0.05%–0.19% during the monsoons. • Radiocesium tends to be preserved in the forest ecosystem due to extremely low output ratios. • The forest floor seems to be a sink of radiocesium contamination than a source for the other ecosystems.

Beef contamination by Cs-134 and Cs-137 in Japan, from the Fukushima Dai-ichi NPP accident

Energy Technology Data Exchange (ETDEWEB)

Kelecom, Alphonse; Cruz, Camila Oliveira da; Paulo Filho, Guilherme de Souza, E-mail: lararapls@hotmail.com, E-mail: camilabiouff@gmail.com, E-mail: akelecom@id.uff.br [Universidade Federal Fluminense (LARARA-PLS/UFF), Niteroi, RJ (Brazil). Lab. de Radiobiologia e Radiometria Pedro Lopes dos Santos; Pereira, Wagner de S., E-mail: pereiraws@gmail.com [Industrias Nucleares do Brasil (UNB), Pocos de Caldas, MG (Brazil). Servico de Radioprotecao. Grupo Multidisciplinar de Radioprotecao

2013-07-01

The most serious earthquake ever registered in Japan occurred on March 11, 2011; it was followed by a tsunami that flowed over the Prefectures of Miyagi and Fukushima destroying roads, cities and rice fields, but also knocking several nuclear power plants. The Dai-ichi plant was seriously damaged and considerable amounts of radioactivity were release contaminating atmosphere, soil, ocean and associated fauna and flora. A major environmental monitoring program started covering the Japanese territory and the sea along the coasts of Miyagi, Fukushima and Ibaraki. Thousands of measurements were released every day by Japanese authorities, the plant operator and Universities principally looking for the presence of I-131, C{sub s}-134 and C{sub s}-137. Drinking water and aliments were seriously contaminated. We here analyze data released during one year on I-131 and C{sub s}-134,137 radioactive concentrations in cattle meat. Along this period I-131, when observed, was present only in trace amounts, but the contamination by cesium isotopes exceeded legal Japanese limit in several Japanese prefectures, and became an acute national and international economic problem. (author)

Beef contamination by Cs-134 and Cs-137 in Japan, from the Fukushima Dai-ichi NPP accident

International Nuclear Information System (INIS)

Kelecom, Alphonse; Cruz, Camila Oliveira da; Paulo Filho, Guilherme de Souza; Pereira, Wagner de S.

2013-01-01

The most serious earthquake ever registered in Japan occurred on March 11, 2011; it was followed by a tsunami that flowed over the Prefectures of Miyagi and Fukushima destroying roads, cities and rice fields, but also knocking several nuclear power plants. The Dai-ichi plant was seriously damaged and considerable amounts of radioactivity were release contaminating atmosphere, soil, ocean and associated fauna and flora. A major environmental monitoring program started covering the Japanese territory and the sea along the coasts of Miyagi, Fukushima and Ibaraki. Thousands of measurements were released every day by Japanese authorities, the plant operator and Universities principally looking for the presence of I-131, C s -134 and C s -137. Drinking water and aliments were seriously contaminated. We here analyze data released during one year on I-131 and C s -134,137 radioactive concentrations in cattle meat. Along this period I-131, when observed, was present only in trace amounts, but the contamination by cesium isotopes exceeded legal Japanese limit in several Japanese prefectures, and became an acute national and international economic problem. (author)

Strengthening safety of nuclear power by learning lessons from the accident at TEPCO's Fukushima-Daiichi Nuclear Power Plant

International Nuclear Information System (INIS)

Omoto, Akira

2011-01-01

The paper first discusses ongoing onsite stabilization activities at Fukushima-Daiichi NPP and a plan for onsite and offsite remedial actions including decontamination and defueling. Four key lessons learned (LL) are raised; safety regulation and safety culture, workable/executable severe accident management procedure, crisis management and design. Global actions for strengthening safety in post-Fukushima era would be built around the IAEA action plan, under recognition of national responsibility. For specific country and plant, a combination of the following may help; a) overall assessment of safety and reflection of Fukushima LL in the light of principles in INSAG-12, b) specific plant assessment of risks from internal, external and security-related events for identifying vulnerabilities and continuous safety improvement, and c) international peer review for comprehensiveness, objectivity and confidence building. In this context, the followings could be worth receiving attention; a) to revisit defense-in-depth, while utilizing risk information, for its completeness and effectiveness (especially, strengthened defense against environmental contamination by effective combination of provisions and management as well as attentiveness and careful attitude towards uncertainties across all layers of defense-in-depth), b) to restore public confidence, c) to cooperate for safety infrastructure in newcomers, d) to build internationally harmonized and cooperative scheme for liability. (author)

Estimation of internal exposure dose from food after the Fukushima Daiichi Nuclear Power Station disaster

International Nuclear Information System (INIS)

Takizawa, Mari; Yoshizawa, Nobuaki; Kawai, Masaki; Miyatake, Hirokazu; Hirakawa, Sachiko; Murakami, Kana; Sato, Osamu; Takagi, Shunji; Suzuki, Gen

2016-01-01

In order to estimate the internal exposure dose from food due to the Fukushima Daiichi Nuclear Power Station accident, total diet study (TDS) has been carried out. TDS is a method for estimating how much of certain chemicals people intake in the normal diet. A wide range of food products are chosen as targets, and the increase or decrease of chemicals depending on processing or cooking is taken into account. This paper glanced at the transition of TDS survey results, and with a focus on the survey results of the market basket (MB) system, which is one of the TDS techniques, it examined a decrease in the committed effective dose per year of radioactive cesium. Although the values of internal exposure dose from food in Fukushima Prefecture and surrounding prefectures are even now in a relatively high tendency compared with those in the distant regions, the difference has been narrowing. According to the attenuation prediction of internal exposure dose in each region of Fukushima Prefecture, the values after 5 years from the accident will be lower than the measured value on the food in market that has been investigated during 1989 and 2005. In addition, the internal exposure dose that was the survey results based on MB system in September - October 2014 was 0.0007 to 0.0022 mSv/year. These values are very small at 1% or less of the upper limit dose of 1 mSv/year as the setting basis of current reference value in Japan. (A.O.)

The relationship between media consumption and health-related anxieties after the Fukushima Daiichi nuclear disaster.

Science.gov (United States)

Sugimoto, Amina; Nomura, Shuhei; Tsubokura, Masaharu; Matsumura, Tomoko; Muto, Kaori; Sato, Mikiko; Gilmour, Stuart

2013-01-01

The Fukushima Daiichi nuclear disaster caused a global panic by a release of harmful radionuclides. In a disaster setting, misusage of contemporary media sources available today can lead to disseminated incorrect information and panic. The study aims to build a scale which examines associations between media and individual anxieties, and to propose effective media usages for future disaster management. The University of Tokyo collaborated with the Fukushima local government to conduct a radiation-health-seminar for a total of 1560 residents, at 12 different locations in Fukushima. A 13 item questionnaire collected once before and after a radiation-seminar was used on factor analysis to develop sub-scales for multiple regression models, to determine relationships between the sub-scales and media type consumed. A paired t-test was used to examine any changes in sub-scale of pre- and post-seminar scores. Three sub-scales were revealed and were associated with different media types: was with rumors, while concern for the future was positively associated with regional-newspapers and negatively with national-newspapers. Anxiety about social-disruption was associated with radio. The seminar had a significant effect on anxiety reduction for all the three sub-scales. Different media types were associated with various heightened concerns, and that a radiation seminar was helpful to reduce anxieties in the post-disaster setting. By tailoring post-disaster messages via specific media types, i.e., radio, it may be possible to effectively convey important information, as well as to calm fears about particular elements of post-disaster recovery and to combat rumors.

WHEN MODEL MEETS REALITY – A REVIEW OF SPAR LEVEL 2 MODEL AGAINST FUKUSHIMA ACCIDENT

Energy Technology Data Exchange (ETDEWEB)

Zhegang Ma

2013-09-01

The Standardized Plant Analysis Risk (SPAR) models are a set of probabilistic risk assessment (PRA) models used by the Nuclear Regulatory Commission (NRC) to evaluate the risk of operations at U.S. nuclear power plants and provide inputs to risk informed regulatory process. A small number of SPAR Level 2 models have been developed mostly for feasibility study purpose. They extend the Level 1 models to include containment systems, group plant damage states, and model containment phenomenology and accident progression in containment event trees. A severe earthquake and tsunami hit the eastern coast of Japan in March 2011 and caused significant damages on the reactors in Fukushima Daiichi site. Station blackout (SBO), core damage, containment damage, hydrogen explosion, and intensive radioactivity release, which have been previous analyzed and assumed as postulated accident progression in PRA models, now occurred with various degrees in the multi-units Fukushima Daiichi site. This paper reviews and compares a typical BWR SPAR Level 2 model with the “real” accident progressions and sequences occurred in Fukushima Daiichi Units 1, 2, and 3. It shows that the SPAR Level 2 model is a robust PRA model that could very reasonably describe the accident progression for a real and complicated nuclear accident in the world. On the other hand, the comparison shows that the SPAR model could be enhanced by incorporating some accident characteristics for better representation of severe accident progression.

Enhancement of organizational resilience in light of the Fukushima Dai-ichi Nuclear Power Plant accident (2). Promoting of attitude-building measures

International Nuclear Information System (INIS)

Oba, Kyoko; Yoshizawa, Atsufumi; Kitamura, Masaharu

2014-01-01

The disaster of Fukushima-Daiichi Nuclear Power Plant was indeed an unprecedented accident. However, the consequence could have been worse without tremendous struggles of the personnel on the site. In order to identify the key factors that enabled such tremendous and self-sacrificing struggles, documents including narrative statements of the personnel have been reviewed. The ultimate purpose of this paper is to enhance operational resilience of nuclear power plants. Out of the four key capabilities proposed in the framework of resilience engineering, the capability to respond has been mainly studied. Particular attention has been paid to attitude of operators which definitely contributed to the outstanding behaviors. Through extensive reviewing activities, number of factors such as the sense of vocation, consciousness for one's own plants, sprit of operator, leadership, followership, comradeship, regional loyalty, connection with family, etc. have been identified as the important driving forces that contributed to the honorable attitude. (author)

Municipalities' opinions about decontamination in special decontamination area. Records from three and a half years after the Fukushima Daiichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Kawasaki, Kota

2015-01-01

This study discusses opinions of 11 municipalities in Fukushima Prefecture designated as Special Decontamination Area as of the end of September 2014, about three and a half years after the Fukushima Daiichi Nuclear Power Plant accident. This study shows that (1) more than half of the municipalities recognize that decontamination activities of the national government which is responsible for decontamination in Special Decontamination Area are inadequate, (2) more than half of the municipalities recognize that residents cannot live their lives with a sense of safety and security unless air radiation dose is reduced to the level before the accident or less than 0.23 μSv/h, and (3) many municipalities recognize that residents will not be able to live their lives with a sense of safety and security even if the national government implements decontamination, (4) many municipalities points out 'Inability to secure enough temporary storage sites' and 'Inappropriateness of the decontamination policy and methods for forests or reservoir' as problems for the promotion of decontamination, and (5) almost all the municipalities recognize the necessity of the installation of interim storage facilities to accelerate the reconstruction of towns. (author)

Feasibility study on phyto-remediation techniques for soil contaminated by the Fukushima Dai-Ichi nuclear power plant accident

Energy Technology Data Exchange (ETDEWEB)

Yuu Ishimori; Akihiro Sakoda [Japan Atomic Energy Agency, Kagamino, Okayama (Japan); Mina Yamada; Yuko Makino; Satoshi Yamada; Hideyasu Fujiyama [Tottori University, Tottori, Tottori (Japan)

2013-07-01

Tottori University and the Japan Atomic Energy Agency carried out jointly the feasibility study on phyto-remediation techniques, which apply to soil contaminated by the TEPCO's Fukushima Dai-ichi NPP accident. This paper illustrates the results from experimental investigations. Experimental investigations include both water-culture tests and field tests. Several plants, mainly halophytes that can specifically absorb more Na than K, and others like sunflower demonstrated for other domestic large-scale tests, were water-cultured and examined for screening. Easily cultivated and harvested plants without harmful effects on subsequent cultivation were also considered. New Zealand spinach was selected as a candidate for demonstrations in fields. The field tests were carried out at two sites of different agricultural types in Minami-soma, Fukushima prefecture. Concentration of {sup 137}Cs in soil is about 4.5 Bq/g-dry as the average of 10 cm depth. The aims of the field tests are to confirm absorption ability and environmental adaptation of the test plants and to document the cost and performance of projects. In conclusion, the absorption of {sup 137}Cs activity per unit area (Bq/m{sup 2}) by New Zealand spinach could be approximately 0.5%. To achieve an effective result in removal of {sup 137}Cs from soil in around a decade, it is required to find the plant which has ten or more times higher absorption capacity than New Zealand spinach. From the consistency of both results in water-culture and field tests, the water-culture test can be valid for screening. In addition, applicable sites will be limited to fields which are too steep or too narrow to use mechanical diggers, and which are free from any restrictions to enter. (authors)

Birth Outcomes after the Fukushima Daiichi Nuclear Power Plant Disaster: A Long-Term Retrospective Study

Science.gov (United States)

Leppold, Claire; Nomura, Shuhei; Sawano, Toyoaki; Ozaki, Akihiko; Tsubokura, Masaharu; Hill, Sarah; Kanazawa, Yukio; Anbe, Hiroshi

2017-01-01

Changes in population birth outcomes, including increases in low birthweight or preterm births, have been documented after natural and manmade disasters. However, information is limited following the 2011 Fukushima Daiichi Nuclear Power Plant Disaster. In this study, we assessed whether there were long-term changes in birth outcomes post-disaster, compared to pre-disaster data, and whether residential area and food purchasing patterns, as proxy measurements of evacuation and radiation-related anxiety, were associated with post-disaster birth outcomes. Maternal and perinatal data were retrospectively collected for all live singleton births at a public hospital, located 23 km from the power plant, from 2008 to 2015. Proportions of low birthweight (increased proportions of low birthweight or preterm births in any year after the disaster (merged post-disaster risk ratio of low birthweight birth: 0.98, 95% confidence interval (CI): 0.64–1.51; and preterm birth: 0.68, 95% CI: 0.38–1.21). No significant associations between birth outcomes and residential area or food purchasing patterns were identified, after adjustment for covariates. In conclusion, no changes in birth outcomes were found in this institution-based investigation after the Fukushima disaster. Further research is needed on the pathways that may exacerbate or reduce disaster effects on maternal and perinatal health. PMID:28534840

Dose limit for emergency workers. Application of Fukushima-Daiichi NPP accident and problems for the future

International Nuclear Information System (INIS)

Sugai, Kenji

2012-01-01

Described are details of management for workers' personal exposure dose, of problems raised and of their solutions taken under various complicated conditions of Fukushima Daiichi Nuclear Power Plant (NPP) Accident (Mar. 2011). As the entrance/exit (en/ex) for the NPP site with regular control were impossible due to the hydrogen explosion which expanded the control area to 20 km distance from the site, Japan Football Village (J-Village) localizing at the border and Important Anti-seismic Building in the site were defined to be the bases of en/ex and of their control, respectively. Flooded 5,000 alarm pocket dosimeters (APD) by tsunami were not usable and only 320 APD remained available. At the quite early stage of working at the site, one representative worker in a group had only one APD. Management of internal exposure was also difficult essentially because the power source of the whole body counter was unavailable. At an early emergent stage alone, workers with higher dose than the limit (100 mSv for emergency) were observed, but >90% of workers were exposed to <50 mSv (the limit for the radiation worker). Six male Tokyo Electric Power Company (TEPCO) personnel were exposed to 250 mSv (specially defined dose limit) or more with the maximum 678.80 mSv, in whom the internal exposure due to radioiodine largely attributed. They were examined for their health by the expert doctors in National Institute of Radiological Sciences, were found free of abnormality and were to be followed up thereafter. Out of 19 female TEPCO personnel, two had exceeded the dose limit 5 mSv/3 mo and other 2, the annual limit 1 mSv. They received the examination by the industrial doctor, were found free of abnormality, but were decided not to work at the site. Recently, about 5,000 APD have been purchased for personal usage and dose management is conducted by bar-coding of individual workers, and internal exposure is managed with 11 whole body counters by once a month measurement in J

Severe Psychological Distress of Evacuees in Evacuation Zone Caused by the Fukushima Daiichi Nuclear Power Plant Accident: The Fukushima Health Management Survey.

Science.gov (United States)

Kunii, Yasuto; Suzuki, Yuriko; Shiga, Tetsuya; Yabe, Hirooki; Yasumura, Seiji; Maeda, Masaharu; Niwa, Shin-Ichi; Otsuru, Akira; Mashiko, Hirobumi; Abe, Masafumi

2016-01-01

Following the Great East Japan Earthquake on March 11, 2011, the nuclear disaster at the Fukushima Daiichi Nuclear Power Plant has continued to affect the mental health status of residents in the evacuation zone. To examine the mental health status of evacuee after the nuclear accident, we conducted the Mental Health and Lifestyle Survey as part of the ongoing Fukushima Health Management Survey. We measured mental health status using the Kessler 6-item psychological distress scale (K6) in a total of 73,569 (response rate: 40.7%) evacuees aged 15 and over who lived in the evacuation zone in Fukushima Prefecture. We then dichotomized responders using a 12/13 cutoff on the K6, and compared the proportion of K6 scores ≥13 and ≤12 in each risk factor including demographic information, socioeconomic variables, and disaster-related variables. We also performed bivariate analyses between mental health status and possible risk factors using the chi-square test. Furthermore, we performed multivariate regression analysis using modified Poisson regression models. The median K6 score was 5 (interquartile range: 1-10). The number of psychological distress was 8,717 (14.6%). We found that significant differences in the prevalence of psychological distress by almost all survey items, including disaster-related risk factors, most of which were also associated with increased Prevalence ratios (PRs). Additionally, we found that psychological distress in each evacuation zone was significantly positively associated with the radiation levels in their environment (r = 0.768, p = 0.002). The earthquake, tsunami and subsequent nuclear accident likely caused severe psychological distress among residents in the evacuation zone in Fukushima Prefecture. The close association between psychological distress and the radiation levels shows that the nuclear accident seriously influenced the mental health of the residents, which might be exacerbated by increased risk perception. To provide

Fukushima Daiichi Unit 1 Uncertainty Analysis-Exploration of Core Melt Progression Uncertain Parameters-Volume II.

Energy Technology Data Exchange (ETDEWEB)

Denman, Matthew R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brooks, Dusty Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-08-01

Sandia National Laboratories (SNL) has conducted an uncertainty analysi s (UA) on the Fukushima Daiichi unit (1F1) accident progression wit h the MELCOR code. Volume I of the 1F1 UA discusses the physical modeling details and time history results of the UA. Volume II of the 1F1 UA discusses the statistical viewpoint. The model used was developed for a previous accident reconstruction investigation jointly sponsored by the US Department of Energy (DOE) and Nuclear Regulatory Commission (NRC). The goal of this work was to perform a focused evaluation of uncertainty in core damage progression behavior and its effect on key figures - of - merit (e.g., hydrogen production, fraction of intact fuel, vessel lower head failure) and in doing so assess the applicability of traditional sensitivity analysis techniques .

Tritium in Japanese precipitation following the March 2011 Fukushima Daiichi Nuclear Plant accident.

Science.gov (United States)

Matsumoto, Takuya; Maruoka, Teruyuki; Shimoda, Gen; Obata, Hajime; Kagi, Hiroyuki; Suzuki, Katsuhiko; Yamamoto, Koshi; Mitsuguchi, Takehiro; Hagino, Kyoko; Tomioka, Naotaka; Sambandam, Chinmaya; Brummer, Daniela; Klaus, Philipp Martin; Aggarwal, Pradeep

2013-02-15

Tritium concentrations in Japanese precipitation samples collected after the March 2011 accident at the Fukushima Dai-ichi Nuclear Power Plant (FNPP1) were measured. Values exceeding the pre-accident background were detected at three out of seven localities (Tsukuba, Kashiwa and Hongo) southwest of the FNPP1 at distances varying between 170 and 220 km from the source. The highest tritium content was found in the first rainfall in Tsukuba after the accident; however concentrations were 500 times less than the regulatory limit for tritium in drinking water. Tritium concentrations decreased steadily and rapidly with time, becoming indistinguishable from the pre-accident values within five weeks. The atmospheric tritium activities in the vicinity of the FNPP1 during the earliest stage of the accident was estimated to be 1.5×10(3) Bq/m(3), which is potentially capable of producing rainwater exceeding the regulatory limit, but only in the immediate vicinity of the source. Copyright © 2012 Elsevier B.V. All rights reserved.

Risk Assessment Strategy for Decommissioning of Fukushima Daiichi Nuclear Power Station

Directory of Open Access Journals (Sweden)

Akira Yamaguchi

2017-03-01

Full Text Available Risk management of the Fukushima Daiichi Nuclear Power Station decommissioning is a great challenge. In the present study, a risk management framework has been developed for the decommissioning work. It is applied to fuel assembly retrieval from Unit 3 spent fuel pool. Whole retrieval work is divided into three phases: preparation, retrieval, and transportation and storage. First of all, the end point has been established and the success path has been developed. Then, possible threats, which are internal/external and technical/societal/management, are identified and selected. “What can go wrong?” is a question about the failure scenario. The likelihoods and consequences for each scenario are roughly estimated. The whole decommissioning project will continue for several decades, i.e., long-term perspective is important. What should be emphasized is that we do not always have enough knowledge and experience of this kind. It is expected that the decommissioning can make steady and good progress in support of the proposed risk management framework. Thus, risk assessment and management are required, and the process needs to be updated in accordance with the most recent information and knowledge on the decommissioning works.

Risk assessment strategy for decommissioning of Fukushima Daiichi Nuclear Power Station

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, Akira; Jang, Sung Hoon [The University of Tokyo, Tokyo (Japan); Hida, Kazuki [Nuclear Damage Compensation and Decommissioning Facilitation Corporation, Tokyo (Japan); Yamanaka, Yasunori [Tokyo Electric Power Company Holdings, Tokyo (Japan); Narumiya, Yoshiyuki [The Kansai Electric Power Co., Inc., Osaka (Japan)

2017-03-15

Risk management of the Fukushima Daiichi Nuclear Power Station decommissioning is a great challenge. In the present study, a risk management framework has been developed for the decommissioning work. It is applied to fuel assembly retrieval from Unit 3 spent fuel pool. Whole retrieval work is divided into three phases: preparation, retrieval, and transportation and storage. First of all, the end point has been established and the success path has been developed. Then, possible threats, which are internal/external and technical/societal/management, are identified and selected. “What can go wrong?” is a question about the failure scenario. The likelihoods and consequences for each scenario are roughly estimated. The whole decommissioning project will continue for several decades, i.e., long-term perspective is important. What should be emphasized is that we do not always have enough knowledge and experience of this kind. It is expected that the decommissioning can make steady and good progress in support of the proposed risk management framework. Thus, risk assessment and management are required, and the process needs to be updated in accordance with the most recent information and knowledge on the decommissioning works.

Mobilizing Mothers: The Fukushima Daiichi Nuclear Catastrophe and Environmental Activism in Japan

Directory of Open Access Journals (Sweden)

Nicole Freiner

2014-02-01

Full Text Available The citizens’ and environmental movements of the 1960s and 70s hadgreat political success in Japan, culminating in the Special Session of the Diet in1970 that enacted 14 anti-pollution laws. These activist groups fought denials ofresponsibility on the part of industry and unresponsiveness on the part of localgovernments. Women were at the forefront of this type of activism during the 1960sand 70s, and led many of the citizens’ environmental movements during this time.More recently, during the environmental catastrophe caused by the meltdown of theFukushima Daiichi nuclear plant, women and mothers have been vocal protesters.Environmental movements have particular political salience because of the successwomen have achieved in this area both in policy change and also roles in formalpolitics. Women have consistently achieved these successes at the same time as theyperformed their roles as mothers and home managers; these roles have been usedstrategically to mobilize women with great effect, and also were central to the valueswith which the citizens’ movements defined themselves politically.

Fukushima. The accident sequence and important causes. Pt. 1/3; Fukushima. Unfallablauf und wesentliche Ursachen. T. 1/3

Energy Technology Data Exchange (ETDEWEB)

Pistner, Christoph [Oeko-Institut e.V., Darmstadt (Germany). Bereich Nukleartechnik und Anlagensicherheit

2013-07-01

On March 11, 2011 a strong earthquake at the east coast of Japan and a subsequent tsunami caused severe damage at the NPP site of Fukushima Daiichi. The article covers the fundamental safety aspects of the accident progress according to the state of knowledge. The principles of nuclear technology and reactor safety are summarized in order to allow the understanding of the accidental sequence. Even two years after the disaster many questions on the sequence of accident events are still open.

Analyzing different HPCI operation modes simulated with ATHLET-CD regarding possible core degradation phenomena in Fukushima-Daiichi unit 3

Energy Technology Data Exchange (ETDEWEB)

Bratfisch, Christoph; Koch, Marco K. [Ruhr-Univ. Bochum (Germany). Reactor Simulation and Safety Group

2017-02-15

For extented application and analyses of the severe accident code ATHLET-CD, the course of the invessel accident in Unit 3 of Fukushima-Daiichi is simulated in the frame of the research project SUBA as a part of the BMBF sponsored collaborative project WASA-BOSS (Weiterentwicklung und Anwendung von Severe Accident Codes - Bewertung und Optimierung von Stoerfallmassnahmen). Investigations, carried out by TEPCO, had shown that the High-Pressure Coolant Injection system (HPCI) might have stopped earlier than expected. A parameter variation was performed to analyze the impact of the tripped HPCI injection regarding the thermohydraulic behaviour as well as the core degradation phenomena.

Lessons Learned in Protection of the Public for the Accident at the Fukushima Daiichi Nuclear Power Plant.

Science.gov (United States)

Callen, Jessica; Homma, Toshimitsu

2017-06-01

What insights can the accident at the Fukushima Daiichi nuclear power plant provide in the reality of decision making on actions to protect the public during a severe reactor and spent fuel pool emergency? In order to answer this question, and with the goal of limiting the consequences of any future emergencies at a nuclear power plant due to severe conditions, this paper presents the main actions taken in response to the emergency in the form of a timeline. The focus of this paper is those insights concerning the progression of an accident due to severe conditions at a light water reactor nuclear power plant that must be understood in order to protect the public.

Lesson and learn from 'Fukushima Daiichi' 180 day's tweets. Inevitable NPP renaissance of the culture and technology

Energy Technology Data Exchange (ETDEWEB)

Tamaki, Masayoshi B., E-mail: a40507a@cc.nagoya-u.ac.jp [TAMAKI Memorial Inst., Komaki, Aichi (Japan)

2011-07-01

Tweeting for severe reactor accident of Toden-EPCO Fukushima Daiichi due to the Eastern Japan M9 earthquake brought me 'Nuclear Renaissance'. Along to the twitter-time-line of the accident consequences, the spent fuel pool, containment, hydrogen explosion, destroyed core, and contamination have been discussed as Inferno. 'Hairo' and back fitting of existing NPPs have been discussed as Purgatorio. NPP Renaissance through nuclear energy synergetics has been discussed as Paradiso. Through these discussions, the East Asia Rim Community takes the role of the 'KOU(one of the keywords in traditional East Asian game 'GO') for realizing 'Nuclear Renaissance' by the 22 Century, resulting in becoming the keystone of the development to the 'All Asia Community'. (author)

Lesson and learn from 'Fukushima Daiichi' 180 day's tweets. Inevitable NPP renaissance of the culture and technology

International Nuclear Information System (INIS)

Tamaki, Masayoshi B.

2011-01-01

Tweeting for severe reactor accident of Toden-EPCO Fukushima Daiichi due to the Eastern Japan M9 earthquake brought me 'Nuclear Renaissance'. Along to the twitter-time-line of the accident consequences, the spent fuel pool, containment, hydrogen explosion, destroyed core, and contamination have been discussed as Inferno. 'Hairo' and back fitting of existing NPPs have been discussed as Purgatorio. NPP Renaissance through nuclear energy synergetics has been discussed as Paradiso. Through these discussions, the East Asia Rim Community takes the role of the 'KOU(one of the keywords in traditional East Asian game 'GO') for realizing 'Nuclear Renaissance' by the 22 Century, resulting in becoming the keystone of the development to the 'All Asia Community'. (author)

Local variance of atmospheric 14C concentrations around Fukushima Dai-ichi Nuclear Power Plant from 2010 to 2012

DEFF Research Database (Denmark)

Chen, Biying; Xu, Sheng; Cook, Gordon T.

2017-01-01

Radiocarbon (14C) has been measured in single tree ring samples collected from the southwest of the Fukushima Dai-ichi Nuclear Power Plant. Our data indicate south-westwards dispersion of radiocarbon and the highest 14C activity observed so far in the local environment during the 2011 accident....... The abnormally high 14C activity in the late wood of 2011 ring may imply an unknown source of radiocarbon nearby after the accident. The influence of 14C shrank from 30 km during normal reactor operation to 14 km for the accident in the northwest of FDNPP, but remains unclear in the southwest....

Detailed deposition density maps constructed by large-scale soil sampling for gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant accident.

Science.gov (United States)

Saito, Kimiaki; Tanihata, Isao; Fujiwara, Mamoru; Saito, Takashi; Shimoura, Susumu; Otsuka, Takaharu; Onda, Yuichi; Hoshi, Masaharu; Ikeuchi, Yoshihiro; Takahashi, Fumiaki; Kinouchi, Nobuyuki; Saegusa, Jun; Seki, Akiyuki; Takemiya, Hiroshi; Shibata, Tokushi

2015-01-01

Soil deposition density maps of gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant (NPP) accident were constructed on the basis of results from large-scale soil sampling. In total 10,915 soil samples were collected at 2168 locations. Gamma rays emitted from the samples were measured by Ge detectors and analyzed using a reliable unified method. The determined radioactivity was corrected to that of June 14, 2011 by considering the intrinsic decay constant of each nuclide. Finally the deposition maps were created for (134)Cs, (137)Cs, (131)I, (129m)Te and (110m)Ag. The radioactivity ratio of (134)Cs-(137)Cs was almost constant at 0.91 regardless of the locations of soil sampling. The radioactivity ratios of (131)I and (129m)Te-(137)Cs were relatively high in the regions south of the Fukushima NPP site. Effective doses for 50 y after the accident were evaluated for external and inhalation exposures due to the observed radioactive nuclides. The radiation doses from radioactive cesium were found to be much higher than those from the other radioactive nuclides. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Rapid analysis of U isotopes in vegetables using ICP-MS. Application to the emergency U monitoring after the nuclear accident at TEPCO's Fukushima Dai-ichi power station

International Nuclear Information System (INIS)

Jian Zheng; Keiko Tagami; Shigeo Uchida

2012-01-01

After the nuclear accident at TEPCO's Fukushima Dai-ichi power station in March, hydrogen explosions and reactor building explosion resulted in releases of radionuclides in the environment. Severe radioactive cesium and iodine contaminations have been observed in fallout deposition samples and soils in the East Japan. Radioactive cesium, iodine, uranium, and transuranic radionuclides were set as the monitoring targets in food safety tests. However, so far, only radioactive cesium and iodine were daily measured and reported by the Ministry of Health, Labour, and Welfare. The tedious and time consuming conventional alpha spectrometric method hampered the emergency monitoring U contamination in foods. In this work, we propose a simple and rapid analytical method for 238 U and 235 U/ 238 U isotope ratio analysis in fresh vegetables. This method was applied to the emergency monitoring of radioactive contamination after the nuclear accident at TEPCO's Fukushima Dai-ichi power station. The results showed no U contamination in fresh vegetables collected in Chiba and Ibaraki prefectures in April and May, 2011. (author)

Relationship between Individual External Doses, Ambient Dose Rates and Individuals' Activity-Patterns in Affected Areas in Fukushima following the Fukushima Daiichi Nuclear Power Plant Accident.

Directory of Open Access Journals (Sweden)

Wataru Naito

Full Text Available The accident at Fukushima Daiichi Nuclear Power Plant on March 11, 2011, released radioactive material into the atmosphere and contaminated the land in Fukushima and several neighboring prefectures. Five years after the nuclear disaster, the radiation levels have greatly decreased due to physical decay, weathering, and decontamination operations in Fukushima. The populations of 12 communities were forced to evacuate after the accident; as of March 2016, the evacuation order has been lifted in only a limited area, and permanent habitation is still prohibited in most of the areas. In order for the government to lift the evacuation order and for individuals to return to their original residential areas, it is important to assess current and future realistic individual external doses. Here, we used personal dosimeters along with the Global Positioning System and Geographic Information System to understand realistic individual external doses and to relate individual external doses, ambient doses, and activity-patterns of individuals in the affected areas in Fukushima. The results showed that the additional individual external doses were well correlated to the additional ambient doses based on the airborne monitoring survey. The results of linear regression analysis suggested that the additional individual external doses were on average about one-fifth that of the additional ambient doses. The reduction factors, which are defined as the ratios of the additional individual external doses to the additional ambient doses, were calculated to be on average 0.14 and 0.32 for time spent at home and outdoors, respectively. Analysis of the contribution of various activity patterns to the total individual external dose demonstrated good agreement with the average fraction of time spent daily in each activity, but the contribution due to being outdoors varied widely. These results are a valuable contribution to understanding realistic individual external doses

An update on radioactive release and exposures after the Fukushima Dai-ichi nuclear disaster.

LENUS (Irish Health Repository)

McLaughlin, P D

2012-09-01

On 11 March 2011, the Richter scale 0.9-magnitude Tokohu earthquake and tsunami struck the northeast coast of Japan, resulting in widespread injury and loss of life. Compounding this tragic loss of life, a series of equipment and structural failures at the Fukushima Dai-ichi nuclear power plant (FDNP) resulted in the release of many volatile radioisotopes into the atmosphere. In this update, we detail currently available evidence about the nature of immediate radioactive exposure to FDNP workers and the general population. We contrast the nature of the radioactive exposure at FDNP with that which occurred at the Chernobyl power plant 25 years previously. Prediction of the exact health effects related to the FDNP release is difficult at present and this disaster provides the scientific community with a challenge to help those involved and to continue research that will improve our understanding of the potential complications of radionuclide fallout.

Japan Reports New Water Leak at Fukushima Daiichi; IAEA Sees No Danger to Public

International Nuclear Information System (INIS)

2014-01-01

Full text: Japanese authorities have informed the IAEA that a leak from an overflowing water storage tank at TEPCO's Fukushima Daiichi Nuclear Power Station was detected in the late evening of 19 February 2014. About 100 cubic metres of radioactive water leaked to the ground adjacent to the tank storage area before the leak was stopped about six hours later. Based on the information provided, IAEA experts consider that the leak poses no danger to the public. IAEA experts also consider actions taken by Japan's Nuclear Regulatory Authority (NRA) following the leak to be appropriate. These include an NRA recommendation that TEPCO remove soil contaminated by the leaked water, which will reduce the risk that contaminated water will be spread further through rain and groundwater. Japan has not asked the IAEA for any assistance in connection with the leak from the tank. The IAEA will continue monitoring developments. (IAEA)

Results of stress tests of European nuclear power plants after the Fukushima-Daiichi accident

International Nuclear Information System (INIS)

Kovacs, Zoltan; Novakova, Helena

2012-01-01

In response to the Fukushima-Daiichi accident, the European Council laid down the requirement that a transparent and comprehensive risk assessment exercise ('stress tests') be carried out at each European nuclear power plant. The stress tests concentrated on the nuclear power plants' safety margins in the light of the lessons learned from the accident. The reviews focused on natural external events including earthquake, tsunami and extreme weather, loss of safety functions, and severe accident management. The stress test procedure comprised 3 steps: (i) The nuclear facility operators performed the stress tests and prepared proposals for safety improvements. (ii) The national regulators performed independent reviews of the stress tests and prepared national reports. (iii) The reports submitted by the national regulators were subjected to review at a European level. The article describes the scope of the stress tests and their results, verified at the European level. (orig.)

The relationship between media consumption and health-related anxieties after the Fukushima Daiichi nuclear disaster.

Directory of Open Access Journals (Sweden)

Amina Sugimoto

Full Text Available BACKGROUND: The Fukushima Daiichi nuclear disaster caused a global panic by a release of harmful radionuclides. In a disaster setting, misusage of contemporary media sources available today can lead to disseminated incorrect information and panic. The study aims to build a scale which examines associations between media and individual anxieties, and to propose effective media usages for future disaster management. METHODS: The University of Tokyo collaborated with the Fukushima local government to conduct a radiation-health-seminar for a total of 1560 residents, at 12 different locations in Fukushima. A 13 item questionnaire collected once before and after a radiation-seminar was used on factor analysis to develop sub-scales for multiple regression models, to determine relationships between the sub-scales and media type consumed. A paired t-test was used to examine any changes in sub-scale of pre- and post-seminar scores. RESULTS: Three sub-scales were revealed and were associated with different media types: was with rumors, while concern for the future was positively associated with regional-newspapers and negatively with national-newspapers. Anxiety about social-disruption was associated with radio. The seminar had a significant effect on anxiety reduction for all the three sub-scales. CONCLUSION: Different media types were associated with various heightened concerns, and that a radiation seminar was helpful to reduce anxieties in the post-disaster setting. By tailoring post-disaster messages via specific media types, i.e., radio, it may be possible to effectively convey important information, as well as to calm fears about particular elements of post-disaster recovery and to combat rumors.

Radioactive Cs-137 discharge from Headwater Forested Catchment in Fukushima after Fukushima Dai-ichi Nuclear Power Plant Accident

Science.gov (United States)

Iwagami, S.; Onda, Y.; Tsujimura, M.; Sakakibara, K.; Konuma, R.

2015-12-01

Radiocesium migration from headwater forested catchment is important perception as output from the forest which is also input to the subsequent various land use and downstream rivers after Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. In this study, Cs-137 concentration of dissolved water, suspended sediment and coarse organic matter such as leaf and branch were monitored. Discharge amount of stream water, suspended sediment and coarse organic matter were measured to investigate the discharge amount of radiocesium and composition of radiocesium discharge form through the headwater stream. Observation were conducted at stream site in four headwater catchments in Yamakiya district, located ~35 km north west of FDNPP from June 2011 (suspended sediment and coarse organic matter: August 2012) to December 2014.The Cs-137 concentration of dissolved water was around 1Bq/l at June 2011. Then declined to 0.1 Bq/l at December 2011. And in December 2014, it declined to 0.01 Bq/l order. Declining trend of Cs-137 concentration in dissolved water was expressed in double exponential model. Also temporary increase was observed in dissolved Cs-137 during the rainfall event. The Cs-137 concentration of suspended sediment and coarse organic matter were 170-49000 Bq/kg and 350-14000 Bq/kg respectably. The Cs-137 concentration of suspended sediment showed good correlation with average deposition density of catchment. The effect of decontamination works appeared in declining of Cs-137 concentration in suspended sediment. Contribution rate of Cs-137 discharge by suspended sediment was 96-99% during a year. Total annual Cs-137 discharge from the catchment were 0.02-0.3% of the deposition.

An assessment of radiation doses at an educational institution 57.8 km away from the Fukushima Daiichi nuclear power plant 1 month after the nuclear accident.

Science.gov (United States)

Tsuji, Masayoshi; Kanda, Hideyuki; Kakamu, Takeyasu; Kobayashi, Daisuke; Miyake, Masao; Hayakawa, Takehito; Mori, Yayoi; Okochi, Toshiyasu; Hazama, Akihiro; Fukushima, Tetsuhito

2012-03-01

On 11 March 2011, the Great East Japan Earthquake occurred. Due to this earthquake and subsequent tsunami, malfunctions occurred at the Fukushima Daiichi nuclear power plant. Radioactive material even reached the investigated educational institution despite being 57.8 km away from the power station. With the goal of ensuring the safety of our students, we decided to carry out a risk assessment of the premises of this educational institution by measuring radiation doses at certain locations, making it possible to calculate estimated radiation accumulation. Systematic sampling was carried out at measurement points spaced at regular intervals for a total of 24 indoor and outdoor areas, with 137 measurements at heights of 1 cm and 100 cm above the ground surface. Radiation survey meters were used to measure environmental radiation doses. Radiation dose rates and count rates were higher outdoors than indoors, and higher 1 cm above the ground surface than at 100 cm. Radiation doses 1 cm above the ground surface were higher on grass and moss than on asphalt and soil. The estimated radiation exposure for a student spending an average of 11 h on site at this educational institution was 9.80 μSv. Environmental radiation doses at our educational institution 57.8 km away from the Fukushima Daiichi nuclear power plant 1 month after the accident were lower than the national regulation dose for schools (3.8 μSv/h) at most points. Differences in radiation doses depending on outdoor surface properties are important to note for risk reduction.

The Fukushima-incident; Fukushima-ulykken

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-11-01

11. March 2011 Japan was hit by an earthquake measuring 9.0 on the Richter scale.The earthquake was followed by a massive tsunami. In all four Japanese nuclear power plants were affected of these events. The nuclear plant Fukushima Daiichi was hit hardest. As the Secretariat for the Crisis Committee for Nuclear Preparedness NRPA followed the situation in Japan closely. In retrospect, the NRPA shared experiences from the Chernobyl accident with Japan. (eb)

Internet usage and knowledge of radiation health effects and preventive behaviours among workers in Fukushima after the Fukushima Daiichi nuclear power plant accident.

Science.gov (United States)

Kanda, Hideyuki; Takahashi, Kenzo; Sugaya, Nagisa; Mizushima, Shunsaku; Koyama, Kikuo

2014-10-01

The Fukushima Daiichi nuclear power plant accident (FDNPPA) was the world's second largest nuclear power plant accident. At the time that it occurred, internet usage prevalence in Japan was as high as 80%. To compare health knowledge on radiation and preventive behaviour between internet users and non-users among adults employed in industries in Fukushima after the nuclear disaster. We conducted a cross-sectional questionnaire study among adults employed in industries in Fukushima 3-5 months after the FDNPPA. Targets were 1394 regular workers who took part in health seminars provided by the Fukushima Occupational Health Promotion Center. After applying the selection criteria, there were 1119 eligible participants. The questionnaire asked for personal characteristics and main sources of information about the FDNPPA, as well as health knowledge on radiation and preventive behaviours following the nuclear accident. We assessed the contribution of each variable using logistic regression analysis. Among the eligible respondents, 637 workers (56.9%) were internet users and 482 (43.1%) were non-users. Internet users had more health knowledge than non-users (average 4.6 radiation-related health conditions in internet users vs 3.6 conditions in non-users) and more preventive behaviours (average 2.6 behaviours in internet users vs 1.9 in non-users). According to logistic regression analyses, internet usage was positively associated with greater health knowledge on radiation (OR 1.13; 95% CI 1.08 to 1.20) and more preventive behaviours (OR 1.14; 95% CI 1.07 to 1.23). Internet usage was significantly and positively associated with greater health knowledge and more preventive behaviours. The internet is a useful method of distributing information to the general public in emergency situations such as a nuclear disaster. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Tritium in Japanese precipitation following the March 2011 Fukushima Daiichi Nuclear Plant accident

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, Takuya, E-mail: t.matsumoto@iaea.org [Isotope Hydrology Section, Division of Physical and Chemical Sciences, International Atomic Energy Agency, Vienna International Centre, 1400 Vienna (Austria); Maruoka, Teruyuki [Division of Integrative Environmental Sciences Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki 305-8572 (Japan); Shimoda, Gen [Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba City, Ibaraki 305-8561 (Japan); Obata, Hajime [Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba 277-8564 (Japan); Kagi, Hiroyuki [Geochemical Research Center, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Suzuki, Katsuhiko [Japan Agency for Marin-Earth Science and Technology, 2-15, Natsushima, Yokosuka, Kanagawa 237-0061 (Japan); Yamamoto, Koshi [Graduate School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Mitsuguchi, Takehiro [215 Ooma Akadoji-cho Konan, 483-8226 (Japan); Usa Marine Biological Institute, Kochi University, 194 Inoshiri, Usa, Tosa, Kochi 781-1164 (Japan); Hagino, Kyoko; Tomioka, Naotaka [Institute for Study of the Earth' s Interior, Okayama University at Misasa, 827 Yamada, Misasa, Tottori 682-0193 (Japan); Sambandam, Chinmaya; Brummer, Daniela; Klaus, Philipp Martin; Aggarwal, Pradeep [Isotope Hydrology Section, Division of Physical and Chemical Sciences, International Atomic Energy Agency, Vienna International Centre, 1400 Vienna (Austria)

2013-02-15

Tritium concentrations in Japanese precipitation samples collected after the March 2011 accident at the Fukushima Dai-ichi Nuclear Power Plant (FNPP1) were measured. Values exceeding the pre-accident background were detected at three out of seven localities (Tsukuba, Kashiwa and Hongo) southwest of the FNPP1 at distances varying between 170 and 220 km from the source. The highest tritium content was found in the first rainfall in Tsukuba after the accident; however concentrations were 500 times less than the regulatory limit for tritium in drinking water. Tritium concentrations decreased steadily and rapidly with time, becoming indistinguishable from the pre-accident values within five weeks. The atmospheric tritium activities in the vicinity of the FNPP1 during the earliest stage of the accident was estimated to be 1.5 × 10{sup 3} Bq/m{sup 3}, which is potentially capable of producing rainwater exceeding the regulatory limit, but only in the immediate vicinity of the source. - Highlights: ► We measured the {sup 3}H contents of Japanese rain collected after the Fukushima accident. ► {sup 3}H level became 30 times higher than pre-accident level in the first rain at Tsukuba. ► Some locality within 220 km from the source showed elevated {sup 3}H levels. ► These high {sup 3}H signals disappear in a few weeks. ► Atmospheric {sup 3}H level at the source during the earliest stage was estimated to be 1500 Bq/m{sup 3}.

Japan's compensation system for nuclear damage - As related to the TEPCO Fukushima Daiichi nuclear accidents

International Nuclear Information System (INIS)

Nomura, Toyohiro; Matsuura, Shigekazu; Takahashi, Yasufumi; Takenaka, Chihiro; Hokugo, Taro; Kamada, Toshihiko; Kamai, Hiroyuki

2012-01-01

Following the TEPCO Fukushima Daiichi nuclear power plant accident, extraordinary efforts were undertaken in Japan to implement a compensation scheme for the proper and efficient indemnification of the affected victims. This publication provides English translations of key Japanese legislative and administrative texts and other implementing guidance, as well as several commentaries by Japanese experts in the field of third party nuclear liability. The OECD Nuclear Energy Agency (NEA) has prepared this publication in co-operation with the government of Japan to share Japan's recent experience in implementing its nuclear liability and compensation regime. The material presented in the publication should provide valuable insights for those wishing to better understand the regime applied to compensate the victims of the accident and for those working on potential improvements in national regimes and the international framework for third party nuclear liability

Aerial radiation monitoring around the Fukushima Dai-ichi Nuclear Power Plant using an unmanned helicopter.

Science.gov (United States)

Sanada, Yukihisa; Torii, Tatsuo

2015-01-01

The Great East Japan Earthquake on March 11, 2011 generated a series of large tsunami that seriously damaged the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), which resulted in the release of radioactive materials into the environment. To provide further details regarding the distribution of air dose rate and the distribution of radioactive cesium ((134)Cs and (137)Cs) deposition on the ground within a radius of approximately 5 km from the nuclear power plant, we carried out measurements using an unmanned helicopter equipped with a radiation detection system. The distribution of the air dose rate at a height of 1 m above the ground and the radioactive cesium deposition on the ground was calculated. Accordingly, the footprint of radioactive plumes that extended from the FDNPP was illustrated. Copyright © 2014 Elsevier Ltd. All rights reserved.

Use of knowledge and experience gained from the Fukushima Daiichi Nuclear Power Station accident to establish the technical basis for strategic off-site response

International Nuclear Information System (INIS)

Miyahara, Kaname; Saito, Kimiaki; Iijima, Kazuki; McKinley, Ian; Hardie, Susan

2015-03-01

This report provides a concise overview of knowledge and experience gained from the activities for environmental remediation after the Fukushima Daiichi (1F) accident. It is specifically tailored for international use, to establish or refine the technical basis for strategic, off-site response to nuclear incidents. It reflects JAEA's key role in the research associated with both remediation of contaminated areas and also the natural contamination migration processes in non-remediated areas, in collaboration with other Japanese and international organisations and research institutes. Environmental monitoring and mapping to define boundary conditions in terms of the distribution of radioactivity and resultant doses, guides the resultant response. Radiation protection considerations set constraints, with approaches developed to estimate doses to different critical groups and set appropriate dose reduction targets. Decontamination activities, with special emphasis on associated waste management, provide experience in evaluation of the effectiveness of decontamination and the pros and cons of different approaches / technologies. The assessment of the natural behaviour of contaminant radionuclides and their mobility in the environment is now focused almost entirely on radiocaesium. Here, the impact of natural mobility in terms of self-cleaning / re-concentration in cleaned areas is discussed, along with possible actions to modify such transport or manage potential areas of radiocaesium accumulation. Many of the conditions in Fukushima are similar to those following past contamination events in other countries, where natural self-cleaning alone has allowed recovery to such an extent that the original incident is now largely forgotten. Decontamination efforts in Japan will certainly accelerate this process. On-going remediation work is based on a good technical understanding of the movement of radiocaesium in the environment and this understanding is being translated into

NEA and its Role in Enhancing the Implementation of Defence in Depth (DiD) in Light of the Fukushima Dai-ichi Accident

Energy Technology Data Exchange (ETDEWEB)

Shimomura, K., E-mail: Kazuo.SHIMOMURA@oecd.org [OECD Nuclear Energy Agency (NEA), Issy-Les-Moulineaux (France)

2014-10-15

Full text: This keynote speech will give an overview of NEA Activities to Enhance Global Nuclear Safety both those core to its work and those that have been initiated after the Fukushima Accident. In particular it will highlight the outcomes of the recently published “NEA report on the Fukushima Daiichi Nuclear Power Plant Accident”. The speech will specifically point out those lessons learnt related to Defence in Depth, and how those were fed into the NEA’s one day workshop on “Challenges and Enhancements to DiD in light of the Fukushima Dai-ichi Accident”, that took place on 5th June 2013. A workshop that brought together the member countries represented on the NEA’s three major standing committees for safety to not only discuss the lessons learnt from the accident but also what the NEA members considered could be done to enhance the understanding and implementation of defence in depth within nuclear safety. Members of these three standing committees, the Committee for Nuclear Regulatory Activities (CNRA), The Committee for Safety of Nuclear Installations (CSNI) and the Committee on Radiation Protection and Public Health (CRPPH) represent a considerable body of knowledge on the application of DiD within the countries using nuclear energy. The outcome of the workshop was the identification of a number of key tasks that NEA would take forward to assist in harmonising and enhancing globally the implementation of the DiD philosophy. The speech will in addition detail how the discussions ranged across the whole of the nuclear safety framework, what conclusions were derived and the process the NEA followed to incorporate those tasks within its future programme of work either by enhancing current activities or creating new ones. (author)

Isotopic ratio and vertical distribution of radionuclides in soil affected by the accident of Fukushima Dai-ichi nuclear power plants

International Nuclear Information System (INIS)

Fujiwara, Takeshi; Saito, Takumi; Muroya, Yusa; Sawahata, Hiroyuki; Yamashita, Yuji; Nagasaki, Shinya; Okamoto, Koji; Takahashi, Hiroyuki; Uesaka, Mitsuru; Katsumura, Yosuke; Tanaka, Satoru

2012-01-01

The results of γ analyses of soil samples obtained from 50 locations in Fukushima prefecture on April 20, 2011, revealed the presence of a spectrum of radionuclides resulted from the accident of the Fukushima Dai-ichi nuclear power plant (FDNPP). The sum γ radioactivity concentration ranged in more than 3 orders of magnitude, depending on the sampling locations. The contamination of soils in the northwest of the FDNPP was considerable. The 131 I/ 137 Cs activity ratios of the soil samples plotted as a function of the distance from the F1 NPPs exhibited three distinctive patterns. Such patterns would reflect not only the different deposition behaviors of these radionuclides, but also on the conditions of associated release events such as temperature and compositions and physicochemical forms of released radionuclides. The 136 Cs/ 137 Cs activity ratio, on the other hand, was considered to only reflect the difference in isotopic compositions of source materials. Two locations close to the NPP in the northwest direction were found to be depleted in short-lived 136 Cs. This likely suggested the presence of distinct sources with different 136 Cs/ 137 Cs isotopic ratios, although their details were unknown at present. Vertical γ activity profiles of 131 I and 137 Cs were also investigated, using 20–30 cm soil cores in several locations. About 70% or more of the radionuclides were present in the uppermost 2-cm regions. It was found that the profiles of 131 I/ 137 Cs activity ratios showed maxima in the 2–4 cm regions, suggesting slightly larger migration of the former nuclide. - Highlights: ► We report the results of γ analyses of soil samples around Fukushima Dai-ichi NPPs. ► The contamination of soils in the northwest of the power plant was considerable. ► The 131 I/ 137 Cs activity ratios exhibited three distinctive patterns. ► Most of 131 I and 137 Cs were present in the uppermost 2-cm regions of soil.

Municipalities' opinions about decontamination in special decontamination area. Records from four and a half years after the Fukushima Daiichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Kawasaki, Kota

2016-01-01

This study discusses opinions of 11 municipalities in Fukushima Prefecture designated as Special Decontamination Area as of the end of September 2015, about four and a half years afters the Fukushima Daiichi Nuclear Power Plant accident. This study shows that (1) more than half of the municipalities recognize that decontamination activities of the national government which is responsible for decontamination in Special Decontamination Area are inadequate, (2) most municipalities recognize that residents cannot live their lives with a sense of safety and security unless air radiation dose is reduced to the level before the accident or less than 0.23 μSv/h, (3) many municipalities recognize that residents will not be able to live their lives with a sense of safety and security even if the national government implements decontamination, (4) municipalities points out 'decontamination of forests or rivers and reconsideration of decontamination methods of forests or rivers', 'securement and maintenance of temporary storage site' and 'setting forth a numeric target concerning decontamination and implementation of additional decontamination after the first decontamination' as issues for the promotion of decontamination, and (5) all the municipalities recognize that that there are a lot of problems concerning the installation of interim storage facilities by the national government. (author)

Advances in safety countermeasures at the Tomari NPP of Hokkaido Electric Power on the basis of Fukushima Daiichi NPP accident. Fire protection and other advances

International Nuclear Information System (INIS)

Shibata, Taku; Dasai, Katsumi

2014-01-01

Fire protections for the nuclear power plants have been based on the fire laws and the conventional guide. After Fukushima Daiichi NPP accident, many safety countermeasures - also about Fire Protection - have been discussed in the Japanese authorities. This paper shows our present activities in the Tomari NPP about the fire protections from the view points of Fire Prevention, Fire Detection/Suppression Systems and Fire Protection, and other advances. (author)

A Study on Pyrochemical Process for Treating Fuel Debris from the Fukushima-Daiichi Reactors

International Nuclear Information System (INIS)

Sakamura, Y.; Iizuka, M.; Koyama, T.; Kitawaki, S.; Nakayoshi, A.; Kofuji, H.

2015-01-01

After the severe accident at Fukushima-daiichi nuclear power plants, CRIEPI and JAEA started a feasibility study on the pyrochemical treatment of the corium that mainly consists of UO 2 -ZrO 2 solid solution. In this study, reduction behaviours of zirconium oxide compounds were investigated in LiCl-Li 2 O salt bath at 923 K. It was experimentally verified that uranium in the simulated corium could be reduced to the metallic form and a part of zirconium was converted to Li 2 ZrO 3 . At higher Li 2 O concentrations in LiCl, Li 2 ZrO 3 was converted to Li 6 Zr 2 O 7 and Li 8 ZrO 6 . In the subsequent electrorefining, Li 2 ZrO 3 reacts with UCl 3 dissolved in the electrolyte salt to give UO 2 precipitate. Therefore, how to remove the Li 2 ZrO 3 from the reduction product is a key point for the pyrochemical treatment of the corium. (authors)

Tsunami simulation of 2011 Tohoku-Oki Earthquake. Evaluation of difference in tsunami wave pressure acting around Fukushima Daiichi Nuclear Power Station and Fukushima Daini Nuclear Power Station among different tsunami source models

International Nuclear Information System (INIS)

Fujihara, Satoru; Hashimoto, Norihiko; Korenaga, Mariko; Tamiya, Takahiro

2016-01-01

Since the 2011 Tohoku-Oki Earthquake, evaluations based on a tsunami simulation approach have had a very important role in promoting tsunami disaster prevention measures in the case of mega-thrust earthquakes. When considering tsunami disaster prevention measures based on the knowledge obtained from tsunami simulations, it is important to carefully examine the type of tsunami source model. In current tsunami simulations, there are various ways to set the tsunami source model, and a considerable difference in tsunami behavior can be expected among the tsunami source models. In this study, we carry out a tsunami simulation of the 2011 Tohoku-Oki Earthquake around Fukushima Daiichi (I) Nuclear Power Plant and Fukushima Daini (II) Nuclear Power Plant in Fukushima Prefecture, Japan, using several tsunami source models, and evaluate the difference in the tsunami behavior in the tsunami inundation process. The results show that for an incoming tsunami inundating an inland region, there are considerable relative differences in the maximum tsunami height and wave pressure. This suggests that there could be false information used in promoting tsunami disaster prevention measures in the case of mega-thrust earthquakes, depending on the tsunami source model. (author)

The total release of xenon-133 from the Fukushima Dai-ichi nuclear power plant accident

International Nuclear Information System (INIS)

Stohl, Andreas; Seibert, Petra; Wotawa, Gerhard

2012-01-01

The accident at the Fukushima Dai-ichi nuclear power plant (FD-NPP) on 11 March 2011 released large amounts of radioactivity into the atmosphere. We determine the total emission of the noble gas xenon-133 ( 133 Xe) using global atmospheric concentration measurements. For estimating the emissions, we used three different methods: (i) using a purely observation-based multi-box model, (ii) comparisons of dispersion model results driven with GFS meteorological data with the observation data, and (iii) such comparisons with the dispersion model driven by ECMWF data. From these three methods, we have obtained total 133 Xe releases from FD-NPP of (i) 16.7 ± 1.9 EBq, (ii) 14.2 ± 0.8 EBq, and (iii) 19.0 ± 3.4 EBq, respectively. These values are substantially larger than the entire 133 Xe inventory of FD-NPP of about 12.2 EBq derived from calculations of nuclear fuel burn-up. Complete release of the entire 133 Xe inventory of FD-NPP and additional release of 133 Xe due to the decay of iodine-133 ( 133 I), which can add another 2 EBq to the 133 Xe FD-NPP inventory, is required to explain the atmospheric observations. Two of our three methods indicate even higher emissions, but this may not be a robust finding given the differences between our estimates. - Highlights: ► We determine the total release of xenon-133 from the Fukushima nuclear accident. ► We used global measurements and a box model, as well as dispersion model estimates. ► Total 133 Xe release is about 14.2-19 EBq, more than Fukushima 133 Xe inventory. ► Additional release of iodine-133 and decay into 133 Xe needed to explain results.

Radiological dose reconstruction for birds reconciles outcomes of Fukushima with knowledge of dose-effect relationships

DEFF Research Database (Denmark)

Garnier-Laplace, Jacqueline; Beaugelin-Seiller, Karine; Della-Vedova, Claire

2015-01-01

We reconstructed the radiological dose for birds observed at 300 census sites in the 50-km northwest area affected by the accident at the Fukushima Daiichi nuclear power plant over 2011-2014. Substituting the ambient dose rate measured at the census points (from 0.16 to 31 μGy h(-1)) with the dos...

Radiological surveillance in Mexico, derived of the accident of the Fukushima Daiichi nuclear power plant; Vigilancia radiologica en Mexico, derivado del accidente en la central nuclear de Fukushima Daiichi

Energy Technology Data Exchange (ETDEWEB)

Aguirre G, J.; Nohpal J, X., E-mail: jaguirre@cnsns.gob.mx [Comision Nacional de Seguridad Nuclear y Salvaguardias, Departamento de Vigilancia Radiologica, Dr. Barragan No. 779, Col. Narvarte, 03020 Mexico D. F. (Mexico)

2012-10-15

March 11, 2011 an earthquake of 9.0 grades in the Richter scale, originated in the coast of Tohoku, Japan, in the Pacific Ocean gave origin to a tsunami that caused an accident in the Fukushima Daiichi nuclear power plant. Due to this accident, derived of the loss of the reactor cooling system, as well as of the prolonged absence of alternating and direct current, radiological protection actions were realized without being able to avoid the liberation of radioactive material to the atmosphere and ocean. The radiological impact of these liberations, not only in Japan but around the world, mainly in the north hemisphere of the Earth, was analyzed by means of environmental dose measurements and radionuclide concentrations in soil and water, among others. In the Mexico case, air samples data were obtained, as well as environmental dose celerity and full-length counts of the people coming from Japan near the disaster area. The present work contains the obtained results of the realized measurements in Mexico, same that have been used to make a summary and analysis of the dispersion in the environment in several countries of the world. (Author)

Measuring Radioactivity from Fukushima Daiichi in New Mexico

International Nuclear Information System (INIS)

McNaughton, Michael

2011-01-01

On March 11, 2011, the Fukushima Daiichi nuclear power plant was damaged by the tsunami that followed the 'Great East Japan Earthquake,' and the reactor subsequently leaked radioactive material. In response, LANL augmented the routine ambient (AIRNET) and stack (Rad-NESHAP) measurements with three high-volume samplers: No.167 at the Old White Rock Fire Station; No.173 at the TA-49 gate, and No.211 at the Los Alamos Medical Center. Previous accidents, such as the Three-Mile-Island accident in 1979 and the Chernobyl accident in 1986, indicated that the most likely releases were (a) the noble gases: krypton and xenon; and (b) the volatile elements: cesium, tellurium, and iodine. At the latitude of Fukushima, the predominant winds across the Pacific Ocean are from west to east, and models predicted that the plume would arrive in the western US on about March 18. By this time the shorter-lived isotopes would have decayed. Therefore, the expected radionuclides were xenon-133, cesium-134, cesium-136, cesium-137, tellurium-132, iodine-131, and iodine-132. As expected, cesium-134, cesium-136, cesium-137, tellurium-132, iodine-131, and iodine-132 were all detected by all three high-volume samplers during March 17-21. The concentrations peaked during the March 24-28 period. After this, concentrations of all nuclides declined. In general, the concentrations were consistent with those measured by the EPA RadNet system and many other monitoring systems throughout the world. At the time of writing, preliminary results from the AIRNET and Rad-NESHAP systems are being reported. More detailed results are described in LA-UR-11-10304 and will be reported in full in the annual environmental report for 2011. All previous releases from nuclear reactors have been dominated by noble gases, primarily krypton and xenon, which are not measured by the high-volume samplers or the AIRNET system. However, in sufficient concentrations these and other fission products would be detected by NEWNET

Design Safety Considerations for Water Cooled Small Modular Reactors Incorporating Lessons Learned from the Fukushima Daiichi Accident

International Nuclear Information System (INIS)

2016-03-01

The global future deployment of advanced nuclear reactors for electricity generation depends primarily on the ability of nuclear industries, utilities and regulatory authorities to further enhance their reliability and economic competitiveness while satisfying stringent safety requirements. The IAEA has a project to help coordinate Member States efforts in the development and deployment of small and medium sized or small modular reactor (SMR) technology. This project aims simultaneously to facilitate SMR technology developers and potential SMR uses, particularly States embarking on a nuclear power programme, in identifying key enabling technologies and enhancing capacity building by resolving issues relevant to deployment, including nuclear reactor safety. The objective of this publication is to explore common practices for Member States, which will be an essential resource for future development and deployment of SMR technology. The accident at the Fukushima Daiichi nuclear power plant was caused by an unprecedented combination of natural events: a strong earthquake, beyond the design basis, followed by a series of tsunamis of heights exceeding the design basis tsunami considered in the flood analysis for the site. Consequently, all the operating nuclear power plants and advanced reactors under development, including SMRs, have been incorporating lessons learned from the accident to assure and enhance the performance of the engineered safety features in coping with such external events

Fukushima 2015: situational analysis and perspectives

International Nuclear Information System (INIS)

Jouette, Isabelle; Le Ngoc, Boris

2015-01-01

This publication proposes an overview of the situation of the Fukushima-Daiichi nuclear power station, four years after the accident. It addresses how the situation is managed in terms of evacuation of nuclear fuels, of storage of contaminated water, and of temporary storage of radioactive wastes produced by decontamination activities. It addresses the decontamination of the environment and the return of populations: progress of decontamination, return of populations, and absence of contamination of food products. The next part addresses the perspectives for the Japanese nuclear sector: a strengthened nuclear safety authority, reactors ready to start up again (some reactors seem to be able to be authorized to soon start up again). It describes how French technology is involved at the service of Fukushima-Daiichi through the Onet Technologies project by the CEA (a remote controlled laser cutting process). It evokes the evolutions of safety requirements in France after the Fukushima accident, notably with the introduction of the hard core notion, and of the FARN or Fast Nuclear Task Force

Psychological distress of residents in Kawauchi village, Fukushima Prefecture after the accident at Fukushima Daiichi Nuclear Power Station: the Fukushima Health Management Survey

Directory of Open Access Journals (Sweden)

Koji Yoshida

2016-08-01

Full Text Available Background To shed light on the mental health of evacuees after the accident at Fukushima Daiichi Nuclear Power Station (FDNPS, we evaluate the results of the Fukushima Health Management Survey (FHMS of the residents at Kawauchi village in Fukushima, which is located less than 30 km from the FDNPS. Methods We conducted the cross-sectional study within the framework of the FHMS. Exposure values were “anorexia,” “subjective feelings about health,” “feelings about sleep satisfaction,” and “bereavement caused by the disaster,” confounding variables were “age” and “sex,” and outcome variables were “K6 points.” We collected data from the FHMS, and employed the Kessler Psychological Distress Scale (K6 and the posttraumatic stress disorder (PTSD Checklist Stressor-Specific Version (PCL-S to carry out the research. A total of 13 or greater was the cut-off for identifying serious mental illness using the K6 scale. The study subjects included residents (n = 542 of over 30 years of age from Kawauchi village, and data were used from the period of January 1, 2012 to October 31, 2012. Results A total of 474 residents (87.5% scored less than 13 points in the K6 and 68 (12.6% scored 13 points or more. The proportion of elderly residents (over 65 years old among people with K6 score above the cut-off was higher than that among people with K6 score below the cut-off (44.1 vs 31.0%, p < 0.05. In addition, the proportion of residents with anorexia and mental illness among people with K6 score above the cut-off was higher than among people with K6 score below the cut-off (p < 0.001 and p < 0.05, respectively. The amount of residents who scored 44 points or more in the PCL-S among people with K6 score above the cut-off was also considerably higher than among people with K6 score below the cut-off (79.4 vs 12.9%, p < 0.001. Interestingly, the proportion of residents who scored more than among people with K6 score above the cut-off and the

Distribution of gamma-ray dose rate in Fukushima prefecture by a car-borne survey method

International Nuclear Information System (INIS)

Sugihara, Shinji; Momoshima, Noriyuki; Maekawa, Akihiro; Ichikawa, Ryohei; Kawamura, Hidehisa

2013-01-01

The Tohoku Pacific Earthquake and Tsunami on March 11, 2011, caused severe damage to the TEPCO Fukushima Dai-ichi NPP. This was followed by a nuclear accident at an unprecedented scale, and huge amounts of radioactive material were released into the environment. The distributions of the gamma-ray dose rate in Fukushima prefecture were measured using a NaI(Tl) scintillation survey meter as part of a car-borne survey method on April 18-21, June 20-22, October 18-21, 2011, and on April 9-11 and July 30 - August 1, 2012. The dose rate near TEPCO Fukushima Dai-ichi NPP and at Iitate-mura, Fukushima-city was high (1 to >30 μSv/h). (author)

Synthesis of the available information about the radioactive contamination of the Japanese terrestrial environment caused by the Fukushima Dai-ichi accident - May 25, 2011

International Nuclear Information System (INIS)

2011-01-01

The French institute of radiation protection and nuclear safety (IRSN) collects and analyses regularly the published data concerning the contamination of the Japanese terrestrial environment caused by the Fukushima Dai-ichi power plant accident. This synthesis presents a status of the data recently obtained since the previous similar note of April 12. The note presents a mapping of 137 Cs and 134 Cs cumulated deposits in a 80 km area around the damaged power plant, an estimation of the cumulated atmospheric precipitations during March 15-16 night, the evolution of the gamma dose rates in the ambient air of several towns of the Fukushima district, the evolution of the 134 Cs+ 137 Cs and 131 I contamination of agriculture food products and of surface and drinking waters. (J.S.)

Examination of a measuring method for fallout radioactivity released by the accident of the Fukushima Dai-ichi NPS. Surface contamination measurement

International Nuclear Information System (INIS)

Yoshii, Taiki; Kawasaki, Satoru

2013-08-01

Radioactive nuclides were released in the atmosphere by the accident of TEPCO's Fukushima Dai-ichi Nuclear Power Station in March, 2011, and they are detected on the materials that had no artificial radioactive nuclides before the accident. Confronted with this situation, NISA issued a guideline titled 'A guideline regarding treatment of materials in nuclear facilities considering the influence of fallout released from the accident of TEPCO's Fukushima Dai-ichi Nuclear Power Station' on March 30, 2012. Nuclear Regulatory Authority refers to applying the existing bylaw until the time to make decision of the updated bylaw. The guideline shows that after judging whether there is the influence of fallout or not, the conventional clearance and NR systems can be used when there is no influence of fallout. On the other hand, the special treatment is required when it is judged that there is the influence. This report describes a specific example of measuring method to evaluate the influence of fallout, in case of surface contamination. This report focused surface contamination of flat object as target. Preliminary investigation shows that the distribution of surface contamination due to fallout is near to lognormal distribution. Therefore, the sampling measurement can be adopted. The average surface contamination of target is decided from sampling data by using 90% upper confidence limit of Chebyshev inequality. Also, the minimum sampling number is decided. The evaluation of the influence of fallout is judged from the result of surface contamination measurement, weight of target and surface area of target. (author)

An extensive study of the concentrations of particulate/dissolved radiocaesium derived from the Fukushima Dai-ichi Nuclear Power Plant accident in various river systems and their relationship with catchment inventory

International Nuclear Information System (INIS)

Yoshimura, Kazuya; Onda, Yuichi; Sakaguchi, Aya; Yamamoto, Masayoshi; Matsuura, Yuki

2015-01-01

An extensive investigation of particulate radiocaesium in suspended solids and dissolved radiocaesium in river water was undertaken at 30 sites in Fukushima and Miyagi Prefectures in December 2012, and their relationships with catchment inventory and the solid/liquid distribution coefficient (K d ) were evaluated. Rivers located in the coastal region on the north side of the Fukushima Dai-ichi Nuclear Power Plant exhibited relatively higher particulate radiocaesium concentrations. Significant correlations were found between concentrations of particulate/dissolved radiocaesium and average catchment inventories, indicating that the concentrations of particulate/dissolved radiocaesium could be approximated from the catchment inventory. Particulate radiocaesium concentration was significantly correlated with dissolved radiocaesium concentration (with the exception of concentrations measured in estuaries), and the geometric mean K d was calculated as 3.6 × 10 5 with a 95% confidence interval of 2.6–5.1 × 10 5 . - Highlights: • Particulate radiocaesium concentration correlated with catchment inventory. • Particulate size can be an important factor of the correlation. • Solid/liquid distribution coefficients were obtained for extensive area

One Year After Fukushima, Nuclear Safety Is Stronger

International Nuclear Information System (INIS)

2012-01-01

Full text: Nuclear power is safer than it was a year ago as the nuclear industry, regulators and governments act on the lessons of Fukushima, but that safety must never be taken for granted, said Yukiya Amano, Director General of the International Atomic Energy Agency (IAEA). Speaking ahead of the first anniversary of the Fukushima Daiichi nuclear accident on 11 March, Amano said a culture of constant vigilance and improvement was vital to ensure that the benefits of nuclear power could be harnessed as safely as humanly possible. 'Nuclear safety is stronger than it was a year ago', he said. 'Fukushima Daiichi was a very serious accident, but we know what went wrong and we have a clear course of action to tackle those causes - not only in Japan, but anywhere in the world. 'Now we have to keep up the momentum. Complacency can kill'. On 11 March 2011 a huge earthquake and tsunami left more than 20 000 people dead or missing in eastern Japan. Amidst widespread destruction, the tsunami slammed into the Fukushima Daiichi Nuclear Power Station, disabling cooling systems and leading to fuel meltdowns in three of the six Units. The accident was a jolt to the nuclear industry, regulators and governments. It was triggered by a massive force of nature, but it was existing weaknesses of design regarding defence against natural hazards, regulatory oversight, accident management and emergency response that allowed it to unfold as it did. For example: The nuclear regulator was not sufficiently independent, allowing weak oversight of the operator, TEPCO, and regulatory requirements fell short of international best practice; Not enough attention was paid to guarding against possible extreme events at the Fukushima Daiichi site, leaving critical safety functions such as cooling systems vulnerable to the tsunami; Training to respond to serious accidents was inadequate, as were mitigation measures to prevent hydrogen explosions and protect the venting system; and Accident command lines

The economics of nuclear decontamination: assessing policy options for the management of land around Fukushima dai-ichi

International Nuclear Information System (INIS)

Munro, Alistair

2013-01-01

Highlights: • Assesses land management options after the Fukushima accident. • Builds a model for exploring intervention and decontaminations options in areas affected by radioactive contamination. • Findings suggest delaying decontamination efforts by 3–10 years is optimal with a central figure of 8.75 years. • Results are sensitive to estimates of the benefits of resettlement. • Poor state of knowledge about some variables that are key for policy actions, such as psychological benefits and costs of resettlement. -- Abstract: In the light of the Japanese government's intensive efforts to decontaminate areas affected by radioactive Caesium from Fukushima dai-ichi nuclear power plant, I create a framework for assessing the merits of management options. In particular I consider delayed intervention as a possible policy. Delay can be optimal because allowing the natural decay of radiation can lower significantly the costs of achieving targets for exposure. Using some benchmark data for Japan I estimate that optimal delay is positive for most reasonable parameter values. Optimal delay generally lies in the range of 3–10 years with a central figure of 8.8 years. There is however considerable uncertainty over some of the key parameter values, particularly with regard to the behaviour of currently evacuated inhabitants

People's awareness toward power generation choices. Two and a half years after the Fukushima Daiichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Kitada, Atsuko

2014-01-01

INSS has conducted continuous opinion polls about nuclear power generation (NPG) sixteen times from 1993 to October 2013. The latest survey is the fourth one since the Fukushima Daiichi Nuclear Power Plant accident and comes two-and-a-half years after the accident. In this study those survey data were analyzed, and the results were as follows. (1) The percent of persons considering the use of NPG as inevitable has dropped a little, but 53% affirm NPG is necessary. (2) It was suggested that the problems such as the leakage of radioactive water at Fukushima Daiichi had a negative impact on the opinion toward use of NPG. (3) Because of the reduction of supply capacity due to long-term suspension of nuclear power plant operations, electric power was insufficient in summer and winter, but people were able to overcome the supply shortage by continuing their power-saving activities. The percentage of people who thought the electric power was insufficient did not increase in particular. The percent who thought a reduction of the NPG should cause the power supply to be unstable, has decreased gradually. (4) Even though five months before the survey was taken there was a nearly 10% electric rate hike to cover increased fuel costs due to having thermal power replace NPG, a lot of people did not think their own electric bill had increased from last year. This suggested that people do not pay much attention to their own electric bills after a rate hike. (5) Negative effects of long-term suspension of NPG have not been recognized and the presence of NPG has declined, and people's support for the policy target of 'zero nuclear power by the 2030s,' has not been reduced, even though the government has changed its goal. (author)

Synthesis of the available information about the radioactive contamination of the Japanese terrestrial environment caused by the Fukushima Dai-ichi accident - July 13, 2011

International Nuclear Information System (INIS)

2011-01-01

The French institute of radiation protection and nuclear safety (IRSN) collects and analyses regularly the published data concerning the contamination of the Japanese terrestrial environment caused by the Fukushima Dai-ichi power plant accident. This synthesis presents a status of the data recently obtained since the previous similar notes of April 12 and May 25. The note presents the detailed activity analysis of several surface soil samples (Iitate Maeda, Namie, Hirono, Fukushima..), a mapping of 137 Cs and 134 Cs cumulated deposits in a 80 km area around the damaged power plant, the evolution of radioactive deposits since March 2011 in different places (Fukushima, Hitachinaka, Saitama, Utsunomiya), the evolution of the 134 Cs+ 137 Cs and 131 I contamination of agriculture food products and of drinking water. The IRSN has detected also a significant contamination of some tea samples imported from the Omaezaki region and intercepted by the French customs. Some information about tea and bamboo shoots cultivation and processing in Japan is added in appendix. (J.S.)

Iodine-129 depth profiles in soil within 30 km from Fukushima Daiichi Nuclear Power Plant

International Nuclear Information System (INIS)

Honda, M.; Matsuzaki, H.; Tsuchiya, Y.S.; Nakano, C.; Yamagata, T.; Nagai, H.; Matsushi, Y.; Maejima, Y.

2013-01-01

Iodine-129 depth profiles of 13 soil cores were analyzed by AMS to evaluate the distribution and the mobility in soil. The cores were sampled from various fields around the Fukushima Daiichi Nuclear Power Plant (FDNPP). Four cores out of the 13 were collected from almost the same position in Kawauchi village crop field 20 km apart from FDNPP at different times between April 2011 and June 2012 to observe the temporal variation of depth profile of "1"2"9I in soil. On the all of 13 soil cores, clear enhancement of the accident origin "1"2"9I was observed. From the crop field soil cores in Kawauchi village, "1"2"9I inventory was estimated as 43.4±2.7 mBq m"-"2 (3.10x10"1"3 atoms m"-"2). There is positive relationship between relaxation length and the elapsed time since the FDNPP accident. The increase rate of the relaxation length is about 1 cm yr"-"1 which should reflect the downward transfer rate of the Fukushima-derived "1"2"9I. Other 9 cores were collected from various fields including crop fields and man-made soils within 30 km from FDNPP on June 2012. Cumulative "1"2"9I inventory fraction [%] from the surface was calculated. The inventory fraction within top 5 cm varied widely, 65-100% with median 82%. Similarly the inventory fraction within top 10 cm varied 82 to 100% with the median 95%. (author)

Condensate demineralizer system for Fukushima Daiichi Nuclear Power Station, the Tokyo Electric Power Co., Inc

International Nuclear Information System (INIS)

Ariyoshi, Shigeki; Ikeda, Yukio; Kuramoto, Kenji; Omori, Yoshi; Yamamoto, Hiroyoshi

1975-01-01

This paper describes the condensate demineralizing equipment recently supplied to the second, third, and fifth power units of the Fukushima Daiichi Nuclear Power Station of the Tokyo Electric Power Company, Inc. The output of this equipment is rated as 4,900 m 3 /h each, which is currently the largest capacity for this type of equipment in Japan. The purpose of this equipment is to remove any ion components and suspended solids contained in condensate to improve its water purity. By doing so, decreasing the corrosion rate of materials used in the plant and, at the same time, decreasing the radioactivity of the condensate, thus easing the whole plant operation can be achieved. The same kind of equipment is also employed at the conventional thermal power stations, but the required functioning and operating mode are quite different. In the case of the nuclear power plant, extremely severe requirements specific with nuclear technology must be met which arise solely from dealing with radioactive substances. Not only the water treatment method, but also layout and arrangement, operation and liquid waste processing methods differ from those for the conventional power plants. The equipment for the sixth unit at Fukushima is now under designing and that for the Tokai No.2 unit of the Japan Atomic Power Company is already under shop fabrication. Both have the rated capacity of 7,300 m 3 /h each, which exceeds far up the capacity of the previously mentioned equipment. (auth.)

Translocation of radiocesium released by the Fukushima Daiichi nuclear power plant accident in Japanese chestnut and chestnut weevil larvae

International Nuclear Information System (INIS)

Sasaki, Yoshito; Ishii, Yasuo; Abe, Hironobu; Mitachi, Katsuaki; Watanabe, Takayoshi; Niizato, Tadafumi

2016-01-01

To examine the translocation of radiocesium scattered by the Fukushima Daiichi nuclear power plant accident that occurred in March 2011 to the Japanese chestnut, we investigated the autoradiography and radiocesium concentration in each part of Japanese chestnuts. The Japanese chestnut fruit has a thin skin between the kernel (cotyledons) and shell; the kernel of the fruit is edible. The 137 Cs concentration in each part of the fruit was found to be almost the same at about 1.0 × 10 4 Bq·kg -1 DW, as well as leaves. The radiocesium concentration in chestnut weevil larvae found on the fruit was approximately one-seventh of that in the kernel. (author)

Visualization of information spreading among 'influencers' on Twitter after Fukushima Daiichi nuclear disaster

International Nuclear Information System (INIS)

Kobayashi, Saori; Onoue, Yosuke; Koyamada, Koji; Tsubokura, Masaharu; Torii, Hiroyuki A.; Uno, Kazuko

2017-01-01

In the aftermath of the Fukushima Daiichi nuclear disaster, there was confusion due to a flood of contradictory opinions about the effects of radiation. In this report data was collected of tweets relating to radiation in 2011. Our aim is to prevent such confusion in the future by considering improvements that should be made in communicating relevant information during times of large-scale disasters. Influencers, the individuals who had an impact on the spread of relevant information, are categorized in three groups based on the contents of their tweets. Our analysis showed that the influencers whose tweets were retweeted the most changed as time passed. We speculated that it was partially caused by the higher number of mutual mentions among the influencers in the group, and verified the hypothesis using network analysis. Results indicated that the density of connection among the influencers is relevant to the ease with which information spreads. (author)

Radiocesium contamination measurement and prospect for future use of Pinus thunbergii pinecones and leaves collected in Fukushima City as children's play and craft materials after the accident at TEPCO's Fukushima Daiichi Nuclear Power Plant

International Nuclear Information System (INIS)

Sugiura, Hiroyuki; Kawano, Keisuke; Kayama, Yukihiko

2013-01-01

Pollutant on the leaves and pinecones of Pinus thunbergii contaminated by radiocesium in Fukushima City were measured, the safe use of the leaves and pinecones as children's toys and craft materials was prospected after the accident at the TEPCO's Fukushima Daiichi nuclear power plant. The radiocesium concentration on Pinus thunbergii leaves on February 22, 2013 was 1/5.7 of the concentration on May 2, 2012. The radiocesium concentration on pinecones was high (16,300 Bq/kg). Radiocesium attached to the latex glove worn when collecting polluted pinecones, and this level fell by 1/5.2 when the polluted glove was washed. Negligible amount of radiocesium was detected in the used glove for collecting of dirty pinecones after painting. It is reasonable to assume that the use of pinecones as craft materials will be possible in the near future because the radiocesium concentration levels are expected to decrease after 2014. (author)

Fukushima. Ending the nuclear era. 2. ed.; Fukushima. Das atomare Zeitalter beenden

Energy Technology Data Exchange (ETDEWEB)

NONE

2015-03-15

The information brochure covers the data on the catastrophic reactor accidents in Fukushima Daiichi following the earth quake and tsunami on March 11, 2011. The chronic radioactive exposure of the Japanese population will be a challenge for the public health policy in the next years. Independent radiation exposures of the TEPCO workers are not available, manipulation of measuring devices, corruption and missing medical examinations are known. The only screening has been performed with respect to thyroid carcinoma, but this is only a small part of the expected cancer incidence. The mentioned screening is performed only in the prefecture Fukushima.

Agricultural approaches of remediation in the outside of the Fukushima Daiichi nuclear power plant

Energy Technology Data Exchange (ETDEWEB)

Sato, Nobuaki [Tohoku University, 2-1-1 Katahira Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Saso, Michitaka [Toshiba Corporation Power Systems Company: 2-1 Ukishima-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-0862 (Japan); Umeda, Miki [Japan Atomic Energy Agency, 4-29 Muramatsu, Tokai, Ibaraki 319-1184 (Japan); Fujii, Yasuhiko [Tokyo Institute of Technology:2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Amemiya, Kiyoshi [Hazama Corporation: 2-2-5 Toranomon, Minato-ku, Tokyo 105-8479 (Japan)

2013-07-01

This paper outlines agricultural approaches of remediation activity done in contaminated areas around the Fukushima Daiichi Nuclear Power Plant. About the decontamination examination of contaminated areas, we have tried the land scale test of a rice field before and after planting by the use of currently recommended methods. Since farmers would carry out the land preparation by themselves, generation of secondary radioactive waste should be as low as possible through the decontamination works. For the radioactive nuclide migration control of rice by wet rice production, several types of decontamination methods such as zeolite addition and potassium fertilization in the soil have been examined. The results are summarized in the 4 following points. 1) Plowing and water discharge are effective for removing radioactive cesium from rice field. 2) Additional potassium fertilization is effective for reducing cesium radioactivity in the product. 3) No significant difference is observed with or without the zeolite addition. 4) Very low transfer factor of cesium from soil to brown rice has been obtained compared with literature values.

Report on the international symposium on radiological issues for Fukushima's revitalized future

International Nuclear Information System (INIS)

Sato, Nobuhiro

2015-12-01

On May 30 - 31, 2015, the fourth and last convention entitled 'International Symposium on Radiological Issues for Fukushima's Revitalized Future' was held in Iizaka Onsen, Fukushima city, under auspices of Institute of Environmental Radioactivity at Fukushima University and other organizations. The following four subjects were the main topics of this symposium: Decontamination/radioactive waste; Environmental radiation/external exposure; Marine/agricultural products, food, internal exposure; and Issues at the Fukushima Daiichi NPP site. The program included 2 invited lectures by overseas guest speakers, 12 oral presentations, 80 poster presentations, and 2 panel discussion sessions, in which over 600 participants consisting of researchers, experts, community dwellers, and young students had lively discussion in a warm and friendly atmosphere. It is noteworthy that several poster presentations were given by high school and junior college students in Fukushima in this international symposium. This report is a collection of the presentation slides and the transcriptions of Q and A sessions for oral lectures as well as the transcriptions of the panel discussion sessions. (J.P.N.)

Time series changes in radiocaesium distribution in tea plants (Camellia sinensis (L.)) after the Fukushima Dai-ichi Nuclear Power Plant accident.

Science.gov (United States)

Hirono, Yuhei; Nonaka, Kunihiko

2016-02-01

Radiocaesium ((134)Cs and (137)Cs) release following the accident at the Fukushima Dai-ichi Nuclear Power Plant, belonging to the Tokyo Electric Power Company caused severe contamination of new tea plant (Camellia sinensis (L.)) shoots by radiocaesium in many prefectures in eastern Japan. Because tea plants are perennial crops, there is the fear that the contamination might last for a long time. The objectives of this study were to reveal time series changes in the distribution of radiocaesium in tea plants after radioactive fallout and to evaluate the effect of pruning on reduction of radiocaesium concentrations in new shoots growing next year. The experimental tea field was located in Shizuoka, Japan, approximately 400 km away from the Fukushima Dai-ichi Nuclear Power Plant in a southwest direction. Time series changes in radiocaesium concentrations in unrefined tea, a tea product primarily produced for making Japanese green tea, from May 2011 to June 2013 and distribution of radiocaesium in tea plants from May 2011 to May 2012 were monitored. The radiocaesium concentrations in unrefined tea exponentially decreased; the effective half-lives for (134)Cs and (137)Cs were 0.30 and 0.36 y during the first 2 y after the accident, respectively. With time, the highest concentrations of (137)Cs moved from the upper to the lower parts of plants. Medium pruning 2-3 months after the accident reduced the concentration of (137)Cs in new shoots harvested in the first crop season of the following year by 56% compared with unpruned tea plants; thus, pruning is an effective measure for reducing radiocaesium concentration in tea. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fukushima Daiichi - Human and organizational facts - Part 1: The events and the organizations which worked in controlling the incident; Fukushima Daiichi - Menschliche und organisatorische Faktoren - Teil 1: Die Ereignisse und die an ihrer Bewältigung beteiligten Organisationen

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-07-01

After the Fukushima Daiichi accident on March 11{sup th}, 2011, the Swiss Federal Nuclear Safety Inspectorate (ENSI) conducted various analyses in order to understand the sequence of events and the contributing factors from both a human as well as an organizational point of view. This analysis considers reports published by TEPCO, the operator of the Fukushima power plants, the Japanese Authorities and IAEA. The deepening of the analysis of the human and organizational aspects became necessary as the accident and its causes are very complex. This complexity is not only the result of technical aspects, but it is also due to the interactions between technical, organizational and human aspects. It is to be considered that additional analyses will be required to exactly understand the physical, organizational and human processes involved. One has to keep in mind the tremendous dimension of the earthquake and the tsunami, as well as the courage and devotedness shown by the actors involved, especially the workers of the Fukushima plants. They had to treat the dramatic issues of the accident, which hit three reactor blocks, and they had to react on the spot to the catastrophic situation with many subsequent earthquakes and, sometimes, without news about their own families. It is necessary to understand the organizational weaknesses with respect to the protection of the plant against the danger of a very large tsunami and the management of a serious accident, in order to learn the necessary lessons. The weaknesses can only be explained by a thorough analysis of the situation which, at the same time, takes the technical environment into account as well as organizational aspects of the accident. The present report considers important event data which are necessary for the understanding of the situation that the various organizations and persons had to master. The role of the organizations in Tokyo and in the Fukushima prefecture is also analyzed. The Fukushima accident is

Fukushima Daiichi Nuclear Accident; based on the Final Report of Atomic Energy Society of Japan

Science.gov (United States)

Sekimura, Naoto

2014-09-01

The Atomic Energy Society of Japan (AESJ) published the Final Report of the AESJ Investigation Committee on Fukushima Daiichi NPS Accident in March 2014. The AESJ is responsible to identify the underlying root causes of the accident through technical surveys and analyses, and to offer solutions for nuclear safety. At the Fukushima Daiichi, Units 1 to 3, which were under operation, were automatically shut down at 14:46 on March 11, 2011 by the Tohoku District-off the Pacific Ocean Earthquake. About 50 minutes later, the tsunami flooded and destroyed the emergency diesel generators, the seawater cooling pumps, the electric wiring system and the DC power for Units 1, 2 and 4, resulting in loss of all power except for an air-cooled emergency diesel generator at Unit 6. Unit 3 lost all AC power, and later lost DC before dawn of March 13. Cooling the reactors and monitoring the results were heavily dependent on electricity for high-pressure water injection, depressurizing the reactor, low pressure water injection, and following continuous cooling. In Unit 3, for example, recent re-evaluation in August 2014 by TEPCO shows that no cooling water was injected into the reactor core region after 8 PM on March 12, leading to the fuel melting from 5:30 AM on March 13. Even though seawater was injected from fire engines afterwards, the rupture of pressure vessel was caused and the majority of melted fuel dropped into the containment vessel of Unit 3. The estimation of amount of radioactive materials such as Xe-133, I-131, Cs-137 and Cs-134, emitted to the environment from Units 1 to 3 is discussed in the presentation. Direct causes of the accident identified in the AESJ Report were, 1) inadequate tsunami measures, 2) inadequate severe accident management measures and 3) inadequate emergency response, post-accident management/mitigation, and recovery measures. These were caused by the following underlying factors, i.e., a) lack of awareness on the roles and responsibilities by

Fukushima. The accident sequence and important causes. Pt. 1/3

International Nuclear Information System (INIS)

Pistner, Christoph

2013-01-01

On March 11, 2011 a strong earthquake at the east coast of Japan and a subsequent tsunami caused severe damage at the NPP site of Fukushima Daiichi. The article covers the fundamental safety aspects of the accident progress according to the state of knowledge. The principles of nuclear technology and reactor safety are summarized in order to allow the understanding of the accidental sequence. Even two years after the disaster many questions on the sequence of accident events are still open.

Radiation-related anxiety among public health nurses in the Fukushima Prefecture after the accident at the Fukushima Daiichi Nuclear Power Station: a cross-sectional study

Science.gov (United States)

Yoshida, Koji; Orita, Makiko; Goto, Aya; Kumagai, Atsushi; Yasui, Kiyotaka; Ohtsuru, Akira; Hayashida, Naomi; Kudo, Takashi; Yamashita, Shunichi; Takamura, Noboru

2016-01-01

Objective In Japan, public health nurses (PHNs) play important roles in managing the health of local residents, especially after a disaster. In this study, we assessed radiation anxiety and the stress processing capacity of PHNs in the Fukushima Prefecture in Japan, after the accident at the Fukushima Daiichi Nuclear Power Station (FDNPS). Methods We conducted a questionnaire survey among the PHNs (n=430) in July of 2015 via postal mail. The questions included demographic factors (sex, age and employment position), knowledge about radiation, degree of anxiety about radiation at the time of the FDNPS accident (and at present), by asking them to answer questions about radiation and the Sense of Coherence-13 (SOC-13). We classified the low and high levels of anxiety by asking them to answer questions about radiation, and compared the anxiety-negative (−) group with the anxiety-positive (+) group. Results Of the PHNs, 269 (62.6%) were classified in the anxiety (−) group and 161 (37.4%) were in the anxiety (+) group. When the multivariate logistic regression analysis was conducted, the PHNs at the time of the accident (OR: 2.37, p=0.007), current general anxieties about radiation (OR: 3.56, pChernobyl accident (OR: 1.69, p=0.035) were significantly associated with anxiety after the FDNPS accident. The mean SOC-13 was 43.0±7.7, with no significant difference between the anxiety (−) group and anxiety (+) group (p=0.47). Conclusions Our study suggested that anxiety about radiation was associated with materials and knowledge about radiation in the PHNs in the Fukushima Prefecture 4 years after the FDNPS accident. It is important for PHNs to obtain knowledge and teaching materials about radiation, and radiation education programmes for PHNs must be established in areas that have nuclear facilities. PMID:27798037

Public worry and question about radiation hazard. Analysis of JHPS web-site opinion on Fukushima I accident

International Nuclear Information System (INIS)

Shimo, Michikuni

2011-01-01

This is a tentative interim report of worry and question appeared in Japan Health Physics Society (JHPS) web-site, which formally started from Mar. 25 in 2011 and had origins of voluntary activity by JHPS members from Mar. 16 and of subsequent Japan MECSST requirement on Mar. 18 concerning the Fukushima Daiichi Power Plant Accident (Fukushima I, Mar. 12). Replying to the health risk in the web essentially stood on the stance that the risk always exists, uncertainty is not unavoidable and risk concerns about public, not about individuals. Major two problems generated were solved by the answering with the manager name not with the responsible individual expert, and by the careful, detailed explanation (long sentence) about the safety dose standards. Questioners were thought mostly to be women of ages between 20 and 40 y. Their living addresses written were Tokyo, Chiba, Fukushima areas and so on, although they were mostly unwritten. The number of questions was 709 (10/day) until July 1; their major three items, when classified in 48, were related to the comparison with the nuclear explosion experiments, Chernobyl Accident and released nuclides from the Fukushima I; and their major key words contained were child (39 questions), health hazard and concern (25), food and water (16), etc. It has become clear that sufficient carefulness is necessary in telling non-experts who scarcely have the fundamental, systematic and mechanistic knowledge, about the assessment of the radiation health risk, where quantitativeness is highly important. The author hopes to publish answers not only as a documentary of the Accident but also as a system of concerned knowledge. (T.T.)

Evaluation of radioactive decontamination effect for paddy soil contaminated by the Fukushima Daiichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Imaizumi, Masayuki; Yoshimoto, Shuhei; Ishida, Satoshi; Okushima, Shuji; Yuuki, Youichi; Hirata, Ryoji

2016-01-01

The National Institute for Rural Engineering performed decontamination of radioactivity at the experimental sites in Iitate Village where paddy fields were contaminated by the Fukushima Daiichi nuclear power plant accident in March 2011 by means of three methods as follows; (1) topsoil removal using soil hardener, (2) removal of soil after paddling with water draining suspended contaminated soil by pumping without manual assistance, and (3) removal of soil after paddling with water draining suspended contaminated soil by pumping with manual assistance. The three methods were evaluated using decontamination factors (DFs) that were determined by applying a variant of inverse analysis using the calculation system for the estimation of decontamination effects (CDE). Input data were provided by surveys using a low-level balloon and a radio-controlled helicopter. The DF values of the three methods were determined on the basis of the Euclidean distances between the simulated and measured dose rates after decontamination. The resulting DFs were > 60 for topsoil removal using soil hardener, 1.4 for slurry pumping, and 2.2 for manually assisted slurry pumping. The area decontaminated by the soil hardening method may have been fully decontaminated, because the distribution of measured dose rates was consistent with the distribution of dose rates calculated for a fully decontaminated area within 20 m in radius. (author)

Estimation of the time-dependent radioactive source-term from the Fukushima nuclear power plant accident using atmospheric transport modelling

Science.gov (United States)

Schoeppner, M.; Plastino, W.; Budano, A.; De Vincenzi, M.; Ruggieri, F.

2012-04-01

Several nuclear reactors at the Fukushima Dai-ichi power plant have been severely damaged from the Tōhoku earthquake and the subsequent tsunami in March 2011. Due to the extremely difficult on-site situation it has been not been possible to directly determine the emissions of radioactive material. However, during the following days and weeks radionuclides of 137-Caesium and 131-Iodine (amongst others) were detected at monitoring stations throughout the world. Atmospheric transport models are able to simulate the worldwide dispersion of particles accordant to location, time and meteorological conditions following the release. The Lagrangian atmospheric transport model Flexpart is used by many authorities and has been proven to make valid predictions in this regard. The Flexpart software has first has been ported to a local cluster computer at the Grid Lab of INFN and Department of Physics of University of Roma Tre (Rome, Italy) and subsequently also to the European Mediterranean Grid (EUMEDGRID). Due to this computing power being available it has been possible to simulate the transport of particles originating from the Fukushima Dai-ichi plant site. Using the time series of the sampled concentration data and the assumption that the Fukushima accident was the only source of these radionuclides, it has been possible to estimate the time-dependent source-term for fourteen days following the accident using the atmospheric transport model. A reasonable agreement has been obtained between the modelling results and the estimated radionuclide release rates from the Fukushima accident.

Heat and fluid flow in accident of Fukushima Daiichi Nuclear Power Plant, Unit 2. Accident scenario based on thermodynamic model

International Nuclear Information System (INIS)

Maruyama, Shigenao

2012-01-01

An accident scenario of Fukushima Daiichi Nuclear Power Plant, Unit 2 is analyzed from the data open to the public. Phase equilibrium process model was introduced that the vapor and water are at saturation point in the vessels. Proposed accident scenario agrees very well with the data of the plant parameters obtained just after the accident. The estimation describes that the rupture time of the reactor pressure vessel (RPV) was at 22:50 14/3/2011. The estimation shows that the rupture time of the pressure containment vessel (RCP) was at 7:40 15/3/2011. These estimations are different from the ones by TEPCO, however; many measured evidences show good accordance with the present scenario. (author)

Dose rate survey inside and outside three public buildings located approximately 40 km northwest of the Fukushima Daiichi Nuclear Power Stations

International Nuclear Information System (INIS)

Yajima, Kazuaki; Iwaoka, Kazuki; Kamada, So

2013-01-01

We surveyed the reduction of the dose rate inside three public buildings compared to the dose rate outside in Kawamata-machi, Fukushima Prefecture. The three buildings—a wooden construction district meeting place, a steel construction public hall, and a reinforced concrete school building—are located approximately 40 km northwest of TEPCO's Fukushima Daiichi Nuclear Power Stations. The dose rate measurement, performed with a NaI(Tl) scintillation survey meter, was carried out on January 19, 2012. We evaluated the reduction of the dose rate inside the building using the reduction factor, which was determined to be the ratio of the dose rate inside the building to that outside the building. The reduction factors 1 m inside from the window were 0.51-0.56 for the wooden building, 0.34-0.51 for the steel construction building, and 0.27-0.31 for the concrete building. The reduction factors at the center of the room were 0.48 for the wooden building, 0.23-0.34 for the steel construction building, and 0.10-0.16 for the concrete building. (author)

Birth Outcomes after the Fukushima Daiichi Nuclear Power Plant Disaster: A Long-Term Retrospective Study

Directory of Open Access Journals (Sweden)

Claire Leppold

2017-05-01

Full Text Available Changes in population birth outcomes, including increases in low birthweight or preterm births, have been documented after natural and manmade disasters. However, information is limited following the 2011 Fukushima Daiichi Nuclear Power Plant Disaster. In this study, we assessed whether there were long-term changes in birth outcomes post-disaster, compared to pre-disaster data, and whether residential area and food purchasing patterns, as proxy measurements of evacuation and radiation-related anxiety, were associated with post-disaster birth outcomes. Maternal and perinatal data were retrospectively collected for all live singleton births at a public hospital, located 23 km from the power plant, from 2008 to 2015. Proportions of low birthweight (<2500 g at birth and preterm births (<37 weeks gestation at birth were compared pre- and post-disaster, and regression models were conducted to assess for associations between these outcomes and evacuation and food avoidance. A total of 1101 live singleton births were included. There were no increased proportions of low birthweight or preterm births in any year after the disaster (merged post-disaster risk ratio of low birthweight birth: 0.98, 95% confidence interval (CI: 0.64–1.51; and preterm birth: 0.68, 95% CI: 0.38–1.21. No significant associations between birth outcomes and residential area or food purchasing patterns were identified, after adjustment for covariates. In conclusion, no changes in birth outcomes were found in this institution-based investigation after the Fukushima disaster. Further research is needed on the pathways that may exacerbate or reduce disaster effects on maternal and perinatal health.

Radiocesium contamination in house dust within evacuation areas close to the Fukushima Daiichi nuclear power plant.

Science.gov (United States)

Shinohara, Naohide; Yoshida-Ohuchi, Hiroko

2018-05-01

Outdoor decontamination efforts have been ongoing since the Fukushima Daiichi nuclear power plant (FDNPP) accident; however, little is known about indoor contamination. Therefore, house dust was sampled based on particle size in 21 wooden buildings (19 residential houses and 2 community centers) within the evacuation area close to the FDNPP, Fukushima Prefecture, Japan. Activities of radiocesium ( 137 Cs) per gram of house dust increased with decreasing particle size (mean: 6.1 × 10 3 , 2.6 × 10 3 , 1.6 × 10 3 , 7.5 × 10 2 , 5.0 × 10 2 , and 4.6 × 10 2  Bq/g for house dust were inversely related to the square of distance from the FDNPP for house dust. It was found that 19%, 33%, and 48% of 137 Cs in house dust were extracted in water, 1 M HCl, and not extracted, respectively. Considering the bioaccessibility and assuming a 20 mg/day daily intake of house dust, the daily doses would be 7.2 Bq/day (mean) and 18 Bq/day (95th percent quantile). These results provide valuable insight into indoor radioactive Cs contamination in the area around the FDNPP and possible oral exposure to indoor radioactive Cs after returning home. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Statement at Fukushima Ministerial Conference on Nuclear Safety, 15 December 2012, Koriyama City, Fukushima Prefecture, Japan

International Nuclear Information System (INIS)

Amano, Y.

2012-01-01

When disaster struck at the Fukushima Daiichi Nuclear Power Plant in March 2011, the IAEA offered immediate assistance to the Plant operators and the Japanese authorities as they tried to regain control over the reactors. We began sharing verified information about the accident with the world and helped to channel international assistance to Japan. A high priority was to do everything we could to help ensure the safety of the people of Japan, especially those in Fukushima Prefecture who were most affected by the crisis. I went to Japan a few days after the accident to meet then Prime Minister Kan. I assured him that Japan could count on the support of the entire international community and stressed the need for full transparency. I sent a number of expert teams to assist in areas such as radiological monitoring, food safety, and analysis of the situation at the Fukushima Daiichi Plant. Four IAEA teams undertook measurements in the Fukushima region, both inside and outside the 20 km evacuation zone. An expert on marine monitoring programmes from the IAEA Environmental Laboratories helped to monitor seawater. Joint teams from the IAEA and the UN Food and Agriculture Organization advised local authorities on technical issues related to food safety and agricultural countermeasures. Some important environmental readings at key points in the unfolding crisis were taken by IAEA experts. Our presence helped to provide reassurance to the people of Japan at a very critical time. It is now one year and nine months since the accident. In that time, we have continued to work closely with Japan. Today, I will sign an important document with Governor Sato of Fukushima Prefecture on our cooperation in the coming years. The IAEA will work closely with the Prefecture in radiation monitoring and decontamination. We will also implement human health projects with Fukushima Medical University.

Fukushima nuclear power plant accident was preventable

Science.gov (United States)

Kanoglu, Utku; Synolakis, Costas

2015-04-01

On 11 March 2011, the fourth largest earthquake in recorded history triggered a large tsunami, which will probably be remembered from the dramatic live pictures in a country, which is possibly the most tsunami-prepared in the world. The earthquake and tsunami caused a major nuclear power plant (NPP) accident at the Fukushima Dai-ichi, owned by Tokyo Electric Power Company (TEPCO). The accident was likely more severe than the 1979 Three Mile Island and less severe than the Chernobyl 1986 accidents. Yet, after the 26 December 2004 Indian Ocean tsunami had hit the Madras Atomic Power Station there had been renewed interest in the resilience of NPPs to tsunamis. The 11 March 2011 tsunami hit the Onagawa, Fukushima Dai-ichi, Fukushima Dai-ni, and Tokai Dai-ni NPPs, all located approximately in a 230km stretch along the east coast of Honshu. The Onagawa NPP was the closest to the source and was hit by an approximately height of 13m tsunami, of the same height as the one that hit the Fukushima Dai-ichi. Even though the Onagawa site also subsided by 1m, the tsunami did not reach to the main critical facilities. As the International Atomic Energy Agency put it, the Onagawa NPP survived the event "remarkably undamaged." At Fukushima Dai-ichi, the three reactors in operation were shut down due to strong ground shaking. The earthquake damaged all offsite electric transmission facilities. Emergency diesel generators (EDGs) provided back up power and started cooling down the reactors. However, the tsunami flooded the facilities damaging 12 of its 13 EDGs and caused a blackout. Among the consequences were hydrogen explosions that released radioactive material in the environment. It is unfortunately clear that TEPCO and Japan's principal regulator Nuclear and Industrial Safety Agency (NISA) had failed in providing a professional hazard analysis for the plant, even though their last assessment had taken place only months before the accident. The main reasons are the following. One

Estimation of in-plant source term release behaviors from Fukushima daiichi reactor cores by forward method and comparison with reverse method

Energy Technology Data Exchange (ETDEWEB)

Kim, Tae Won; Rhee, Bo Wook; Song, Jin Ho; Kim, Sung Il; Ha, Kwang Soon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2017-06-15

The purpose of this paper is to confirm the event timings and the magnitude of fission product aerosol release from the Fukushima accident. Over a few hundreds of technical papers have been published on the environmental impact of Fukushima Daiichi accident since the accident occurred on March 11, 2011. However, most of the research used reverse or inverse method based on the monitoring of activities in the remote places and only few papers attempted to estimate the release of fission products from individual reactor core or from individual spent fuel pool. Severe accident analysis code can be used to estimate the radioactive release from which reactor core and from which radionuclide the peaks in monitoring points can be generated. The basic material used for this study are the initial core inventory obtained from the report JAEA-Data/Code 2012–018 and the given accident scenarios provided by Japanese Government or Tokyo Electric Power Company (TEPCO) in official reports. In this research a forward method using severe accident progression code is used as it might be useful for justifying the results of reverse or inverse method or vice versa. The release timing and amounts to the environment are estimated for volatile radioactive fission products such as noble gases, cesium, iodine, and tellurium up to 184 hours (about 7.7 days) after earthquake occurs. The in-plant fission product behaviors and release characteristics to environment are estimated using the severe accident progression analysis code, MELCOR, for Fukushima Daiichi accident. These results are compared with other research results which are summarized in UNSCEAR 2013 Report and other technical papers. Also it may provide the physically based arguments for justifying or suspecting the rationale for the scenarios provided in open literature. The estimated results by MELCOR code simulation of this study indicate that the release amount of volatile fission products to environment from Units 1, 2, and 3

Epidemiological studies of Fukushima residents exposed to ionising radiation from the Fukushima Daiichi Nuclear Power Plant prefecture—a preliminary review of current plans

International Nuclear Information System (INIS)

Akiba, Suminori

2012-01-01

It is now more than six months since the beginning of the accident on 11 March 2011 at the Fukushima Daiichi Nuclear Power Plant in Japan. The Japanese government and local health authorities have started to collect the information necessary to estimate radiation doses received by those living in the area around the plant, drafted plans for the health care of residents, and started to implement some of them. This paper reviews and discusses the studies necessary for risk evaluation of cancer and non-cancer diseases, including those already planned, mainly from the view point of evaluating health risk using epidemiological approaches. In the long run, it is important to establish a cohort with a control group. Even if the cumulative doses are estimated to be so low that it is difficult to evaluate the risk of cancer and non-cancer diseases, it is necessary to conduct such a study to reassure residents. The health care programme of the Fukushima Prefecture government, including health check-ups of residents, will help to assess indirect effects of radiation exposure, including psychological problems. The success of any studies of radiation epidemiology depends on the collection of accurate information on radiation doses received by the study subjects. However, some of the dosimetry surveys were not conducted in a timely manner. (It should be recognised, though, that such a problem might have been inevitable, considering the chaotic condition after the nuclear accident.) Accurate estimation of the radiation dose received by each resident is not only important for scientific risk evaluation but also to inform each resident about his or her potential risk. Otherwise, residents will bear an undue psychological burden from uncertainties regarding their radiation exposure and its health consequences. One of other important tasks in Fukushima is the improvement of the quality of the regional cancer registry in this prefecture. It is also important to start thyroid cancer

What nuclear industry after Fukushima?; Quel nucleaire apres Fukushima?

Energy Technology Data Exchange (ETDEWEB)

Barre, Bertrand [Institut national des sciences et techniques nucleaires, CEA-Saclay, 91191 Gif-sur-Yvette Cedex (France)

2011-07-01

Nuclear power experienced a fast growth during the 70's and 80's, but a quasi-stagnation during the 90's. Since the beginning of the 21. century, a so-called renaissance could be witnessed, fuelled by concerns about energy security of supply, volatility of oil and gas prices, fear of an incoming 'peak oil', and, last but not least, the threat of global climate change due to the anthropogenic emissions of greenhouse effect gases. Then, on March 11 2011, a monster earthquake followed by a violent tsunami triggered an accident which all but destroyed four nuclear reactors on the Fukushima-Daiichi site, on the east coast of Honshu, the main Japanese island. There was meltdown in three reactor cores, hydrogen explosions which blew off the upper structures of four reactor buildings, and massive radioactive contamination of a spread of land north-west of the site as well as radioactive releases to the ocean. This accident triggered reactions of various intensities throughout the world, awakening the fears, and questions raised 25 years before by the Chernobyl accident. But the tsunami did not make the fundamentals of the renaissance disappear. After a pause, to fully learn lessons from the accident, the renaissance is likely to start again, all the much since the 'third generation' nuclear plants would have survived unscathed the Fukushima earthquake and tsunami. (author)

Summary of atmospheric measurements and transport pathways of radioactive materials released by the Fukushima Daiichi Nuclear Power Plant accident

Energy Technology Data Exchange (ETDEWEB)

Tsuruta, Haruo; Nakajima, Teruyuki [Tokyo Univ., Atmosphere and Ocean Research Inst., Kashiwa, Chiba (Japan); Takigawa, Masayuki [Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa (Japan)

2012-11-15

After the Fukushima Daiichi Nuclear Power Plant (FD1NPP) accident, a continual monitoring of atmospheric radionuclides was independently carried out at several stations by different research institutions in the Kanto area south of Fukushima prefecture. No such measurements were made in the Fukushima area. Although the sampling methodology varied from one station to the next, the following results were found by the analysis of these data during March 13-31, 2011. High concentrations of {sup 131}I, {sup 134}Cs, and {sup 137}Cs in the atmosphere were observed in the first period (March 15-16, 2011) and the second period (March 20-23, 2011). According to a numerical simulation by an atmospheric transport model, these radionuclides were directly transported to the stations from the FD1NPP. The ratio of {sup 131}I to {sup 137}Cs in the atmosphere was around 10 in the first period and on March 20-21, while the ratio in the periods outside the first period and the March 20-21 was around 100. According to the measurements of gaseous {sup 131}I ({sup 131}I(g)) and particulate {sup 131}I ({sup 131}I(a)) which were performed separately at two stations, at least half of the total {sup 131}I (the sum of {sup 131}I(g) and {sup 131}I(a)) sampled was particulate {sup 131}I in the first and second periods, although {sup 131}I(a) was 20-40% of the total {sup 131}I in the periods outside the first and second periods. (author)

The Fukushima Daiichi Nuclear Power Plant accident. How has the Geochemical Society of Japan been grappling with it?

International Nuclear Information System (INIS)

Ebihara, Mitsuru

2012-01-01

On March 11 in 2011, a great earthquake hit the eastern part of mainland Japan and triggered several gigantic tsunami waves, which destroyed the coastal areas in Tohoku and north Kanto districts facing the Pacific Ocean. The earthquake and a tsunami fatally damaged the Fukushima Daiichi Nuclear Power Plant (FDNPP) and took over the nuclear reactors. Eventually a large amount of radioactive materials was released into the environment. Radioactive nuclides were detected in a wide area including remote areas such as the Kanto district and metropolitan Tokyo. Some radioactive nuclides were detected in the United States and in some European countries, implying that radioactive materials released into the atmosphere and oceans were carried by global atmospheric and oceanic circulations all over the world. The Geochemical Society of Japan (GSJ) initiated several actions soon after the earthquake and the FDNPP accident. For instance, in response to the society's appeal, many GSJ members joined the project to map the distribution of several radioactive nuclides in soil samples in the Fukushima Prefecture. The members' contributions led to the creation of several distribution maps of radioactive nuclides, such as 134,137 Cs, 131 I, and 132 Te, trapped in soils in Fukushima. Another approach was to set the occasion for presenting the members' activities related to the FDNPP accident. For instance, the GSJ proposed to organize special sessions on research activities related to the FDNPP accident on the occasions of the 2011 Goldschmidt Conference and 2011 Annual Meeting of the GSJ. In this article, how the GSJ have been grappling with the PDNPP accident was chronologically described, especially from a viewpoint of an alliance with other organizations. (author)

Radioactivity in vegetation at the Fukushima area. A study on contamination by radionuclides released from TEPCO's Fukushima Daiichi nuclear power plants

International Nuclear Information System (INIS)

Momoshima, Noriyuki; Sugihara, Sinji; Ozawa, Ryosuke; Nakama, Akimitsu; Ichikawa, Ryohei; Maekawa, Akihiro

2013-01-01

Leaves of Kudzu collected from the Fukushima Daiichi NPP accident contamination area are shown to exhibit high levels of "1"3"4Cs and "1"3"7Cs activity. Radioactive dusts that attached to the leaf surface were measured at significant levels (as confirmed by IP) for a sample collected in 2011, but at lower levels for samples collected in 2012. This suggests that root uptake would be considered a major source of internal contamination prior to collection of the 2012 samples. The surface and internal contamination was evaluated for two leaves of the 2011 sample and the radiocesium attached contributed to 13% and 63% of the total activity, respectively. The "1"3"4"+"1"3"7Cs activity of the 2012 samples showed a positive correlation with the radiation dose rate measured at the sampling points; however, the "1"3"4"+"1"3"7Cs activity estimated as an internal fraction still seemed high when compared to that of the 2011 sample. These results suggest that the surface absorption of radiocesium from attached dusts is likely responsible for the observed high internal activity. (author)

Development of remote decontamination technologies improving internal environment of reactor buildings at Fukushima Daiichi Nuclear Power Station

International Nuclear Information System (INIS)

Hotta, Koji; Hayashi, Hirotada; Sakai, Hitoshi

2016-01-01

The reactor buildings at the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co., Inc., which was seriously damaged by the Great East Japan Earthquake of March 11, 2011, have been highly contaminated by radioactive materials. To safely and efficiently advance the processes related to the forthcoming decommissioning of the reactors, it is necessary to improve the hazardous environment inside the reactor buildings. During the more than four years that have elapsed since the Great East Japan Earthquake, Toshiba has been implementing various measures to reduce the ambient dose rates inside the reactor buildings through decontamination work and participation in a national project for the development of remote decontamination technologies for reactor buildings. A variety of vehicles and technologies to support decontamination work have been developed through these activities, and are significantly contributing to improvement of the environment inside the reactor buildings. (author)

Case study of medical evacuation before and after the Fukushima Daiichi nuclear power plant accident in the great east Japan earthquake.

Science.gov (United States)

Okumura, Tetsu; Tokuno, Shinichi

2015-01-01

In Japan, participants in the disaster-specific medical transportation system have received ongoing training since 2002, incorporating lessons learned from the Great Hanshin Earthquake. The Great East Japan Earthquake occurred on March 11, 2011, and the very first disaster-specific medical transport was performed. This article reviews in detail the central government's control and coordination of the disaster medical transportation process following the Great East Japan Earthquake and the Fukushima Daiichi Nuclear Power Plant Accident. In total, 124 patients were air transported under the coordination of the C5 team in the emergency response headquarter of the Japanese Government. C5 includes experts from the Cabinet Office, Cabinet Secretariat, Fire Defense Agency, Ministry of Health, Labour and Welfare, and Ministry of Defense. In the 20-30 km evacuation zone around the Fukushima Daiichi nuclear power plant, 509 bedridden patients were successfully evacuated without any fatalities during transportation. Many lessons have been learned in disaster-specific medical transportation. The national government, local government, police, and fire agencies have made significant progress in their mutual communication and collaboration. Fortunately, hospital evacuation from the 20-30 km area was successfully performed with the aid of local emergency physicians and Disaster Medical Assistance Teams (DMATs) who have vast experience in patient transport in the course of day-to-day activities. The emergency procedures that are required during crises are an extension of basic daily procedures that are performed by emergency medical staff and first responders, such as fire fighters, emergency medical technicians, or police officers. Medical facilities including nursing homes should have a plan for long-distance (over 100 km) evacuation, and the plan should be routinely reevaluated with full-scale exercises. In addition, hospital evacuation in disaster settings should be

Direction on characterization of fuel debris for defueling process in Fukushima Daiichi Nuclear Power Station

International Nuclear Information System (INIS)

Yano, Kimihiko; Kitagaki, Toru; Ikeuchi, Hirotomo; Wakui, Ryohei; Higuchi, Hidetoshi; Kaji, Naoya; Koizumi, Kenji; Washiya, Tadahiro

2013-01-01

For the decommissioning of Fukushima Daiichi Nuclear Power Station (1F), defueling of the fuel debris in the reactor core of Units 1-3 is planned to start within 10 years. Preferential items in the characterization of the fuel debris were identified for this work, in which the procedure and handling tools were assumed on the basis of information on 1F and experience after the Three Mile Island Unit 2 (TMI-2) accident. The candidates for defueling tools for 1F were selected from among the TMI- 2 defueling tools. It was found that they could be categorized into six groups according to their operating principles. The important properties of the fuel debris for defueling were selected considering the effect of the target materials on the tool performance. The selected properties are shape, size, density, thermal conductivity, heat capacity, melting point, hardness, elastic modulus, and fracture toughness. Of these properties, the mechanical properties (hardness, elastic modulus, fracture toughness) were identified as preferential items, because too few data on these characteristics of fuel debris are available in past severe accident studies. (authors)

Screening survey on thyroid exposure for children after the Fukushima Daiichi Nuclear Power Station accident

Energy Technology Data Exchange (ETDEWEB)

Kim, Eunjoo; Kurihara, Osamu; Suzuki, Toshikazu; Matsumoto, Masaki; Fukutsu, Kumiko; Yamada, Yuji; Sugiura, Nobuyuki; Akashi, Makoto [National Institute of Radiological Sciences, Research Center for Radiation Emergency Medicine, Chiba, Chiba (Japan)

2012-11-15

In response to a serious accident at the Fukushima Daiichi Nuclear Power Station, National Institute of Radiological Sciences (NIRS) established a protocol for a screening survey of thyroid exposure for children living in areas where thyroid doses were predicted to be high. The aim of the screening survey was to implement measurements for a large number of subjects with conventional NaI(Tl) scintillation survey meters. This protocol was applied to the screening survey of 1,149 children at five locations in three municipalities (Kawamata Town, Iitate Village and Iwaki City). Among 1,080 children (excluding 69 subjects from evaluation), there were no subjects who exceeded a screening level (0.2 {mu}Sv h{sup -1}) corresponding to a thyroid equivalent dose of 100 mSv (for the age group of 1-y-old as of March 24). No significant signals were detected in 55.4% of these subjects and the maximum dose was found to be 43 mSv. This paper presents details on the protocol as well as results of the screening survey. (author)

Whole-body counting of Fukushima residents after the TEPCO Fukushima Daiichi Nuclear Power Station accident

Energy Technology Data Exchange (ETDEWEB)

Momose, Takumaro; Takada, Chie; Nakagawa, Takahiro; Nakai, Katsuta; Kurihara, Osamu; Tsujimura, Norio; Furuta, Sadaaki [Japan Atomic Energy Agency, Nuclear Fuel Cycle Engineering Laboratories, Tokai, Ibaraki (Japan); Ohi, Yoshihiro; Murayama, Takashi; Suzuki, Takashi [Japan Atomic Energy Agency, Nuclear Science Research Institute, Tokai, Ibaraki (Japan); Uezu, Yasuhiro [Japan Atomic Energy Agency, Fukushima Environmental Safety Center, Fukushima, Fukushima (Japan)

2012-11-15

At the request of the Fukushima government, the Japan Atomic Energy Agency (JAEA) started whole-body counting of residents on July 11, 2011, to assess radiation exposure after the TEPCO Fukushima Daiichi Nuclear Power Station accident. JAEA has examined residents in Iitate, Kawamata, Namie, and eight other local communities. The measurement capacity of the whole-body counting device is approximately 100 persons per day, and the total number of people to measure reached 9,927 by the end of January 2012. Two types of whole-body counter (WBC), each of which has two large-sized NaI(Tl) detectors, were used to perform the measurements. Physical phantoms (a Canberra RMC-II transfer phantom or a water-filled block phantom developed by JAEA) were used to perform the efficiency calibration of the WBCs, and results of this calibration were verified by comparing them with different-sized BOttle Mannequin ABsorber (BOMAB) phantoms imitating an adult male, a 10-year-old child, and a 4-year-old child. Short half-life radionuclides (e.g., {sup 131}I) originating from the accident were not detected in the present work, because the measurements were made starting four months after the accident. These measurements showed that about 80% of the residents were below a minimum detectable amount (MDA) of the measured radionuclides in the whole-body content. No artificial nuclides other than {sup 134}Cs and {sup 137}Cs were detected in the present whole-body counting. The maximum whole-body content of radiocesium ({sup 134}Cs and {sup 137}Cs in total) was 2.7 kBq for children (< 8 years old) and 14 kBq for adults. The radioactivity ratio ({sup 137}Cs/{sup 134}Cs) was estimated to be from 1.12 to 1.26. An acute intake scenario via inhalation of radiocesium was assumed in the present dose estimation for all the residents who were measured by the end of January 2012. The committed effective dose (CED) to 99.8% of the residents was found to be below 1 mSv. There were only 25 subjects with a

Perceived Workplace Interpersonal Support Among Workers of the Fukushima Daiichi Nuclear Power Plants Following the 2011 Accident: The Fukushima Nuclear Energy Workers' Support (NEWS) Project Study.

Science.gov (United States)

Takahashi, Sho; Shigemura, Jun; Takahashi, Yoshitomo; Nomura, Soichiro; Yoshino, Aihide; Tanigawa, Takeshi

2017-10-10

The 2011 Fukushima Daiichi nuclear accident was the worst nuclear disaster since Chernobyl. The Daiichi workers faced multiple stressors (workplace trauma, victim experiences, and public criticism deriving from their company's post-disaster management). Literatures suggest the importance of workplace interpersonal support (WIS) in enhancing psychological health among disaster workers. We sought to elucidate the role of their demographics, disaster-related experiences, and post-traumatic stress symptoms on perceived WIS. We analyzed self-report questionnaires of 885 workers 2-3 months post-disaster. We used sociodemographic and disaster exposure-related variables and post-traumatic stress symptoms (measured by the Impact of Event Scale-Revised) as independent variables. We asked whether WIS from colleagues, supervisors, or subordinates was perceived as helpful, and used yes or no responses as a dependent variable. Logistic regression analyses were performed to assess correlates of WIS. Of the participants, one-third (34.7%) reported WIS. WIS was associated with younger age (20-28 years [vs 49-], adjusted odds ratio [aOR]: 3.25, 95% CI: 1.99-5.32), supervisory work status (aOR: 2.30, 95% CI: 1.35-3.92), and discrimination or slur experience (aOR: 1.65, 95% CI: 1.08-2.53). Educational programs focusing on WIS might be beneficial to promote psychological well-being among nuclear disaster workers, especially younger workers, supervisors, and workers with discrimination experiences. (Disaster Med Public Health Preparedness. 2017; page 1 of 4).

iB1350 no.1. A generation III.7 reactor after the Fukushima Daiichi accident

International Nuclear Information System (INIS)

Sato, Takashi; Matsumoto, Keiji; Hosomi, Kenji; Kojima, Yoshihiro; Taguchi, Keisuke

2017-01-01

iB1350 stands for an innovative, intelligent and inexpensive BWR 1350. It is the first generation III.7 reactor after the Fukushima Daiichi accident. It has incorporated lessons learned from the Fukushima Daiichi accident and WENRA safety objectives. It has innovative safety to cope with devastating natural disasters including a giant earthquake, a large tsunami and a monster hurricane. The iB1350 can survive passively such devastation and a very prolonged SBO without any support from the outside of a site up to 7 days even preventing core melt. It, however, is based on the well-established proven ABWR design. The NSSS is exactly the same as that of the current ABWR. As for safety design, it has a double cylinder RCCV (Mark W containment) and in-depth hybrid safety systems (IDHS). The Mark W containment has double FP confinement barriers and the in-containment filtered venting system (IFVS) that enable passively no emergency evacuation outside the immediate vicinity of the plant for a SA. It has a large volume to hold hydrogen, an innovative core catcher (iCC), a passive flooding system and an innovative passive containment cooling system (iPCCS) establishing passively practical elimination of containment failure even in a long term. The IDHS consists of 4 division active safety systems for a DBA, 2 division active safety systems for a SA and built-in passive safety systems (BiPSS) consisting of an isolation condenser (IC) and the iPCCS for a SA. While the conventional PCCS can never cool the S/P, the iPCCS can automatically cool the S/P directly even in a DBA LOCA. That makes it possible for the iB1350 to optimize the active safety systems for a DBA. Sato came up with several optimized configurations of the IDHS that are expected to achieve further cost reduction and enhance its reliability resulting from passive feature of the iPCCS. The IC/iPCCS pool has enough capacity for 7 day grace period. The IC/iPCCS heat exchangers, the core and the spent fuel pool are

¹²⁹I and ¹³⁷Cs in groundwater in the vicinity of Fukushima Dai-ichi nuclear power plant

DEFF Research Database (Denmark)

Xu, Sheng; Zhang, Luyuan; Freeman, Stewart P.H.T.

2016-01-01

. The minimal 129I/137Cs activity ratios in the groundwater are more than 2–500 times higher than the FDNPP source ratio. These data can be explained by rainwater infiltrating through the surface soils, with the more water-soluble 129I preferentially extracted into the aqueous phase and the 137Cs preferentially......This paper reports iodine (127I and 129I) and cesium (137Cs) isotope concentrations in groundwater of confined and unconfined aquifers in the vicinity of the Fukushima Dai-ichi nuclear power plant (FDNPP). 127I and 129I concentrations range from 2–13 μg/L and 5 × 107–8 × 1010 atom/L respectively...... retained in the soil....

Supportive measures toward safety assurance of post-disaster Fukushima Daiichi Nuclear Power Plant

International Nuclear Information System (INIS)

Hatazawa, Mamoru

2012-01-01

Toshiba group had taken supportive measures toward safety assurance of post-disaster Fukushima Daiichi Nuclear Power Plant, such as active water treatment, upgrade core cooling capability with additional water injection rout of core spray spargers, alternative cooling system of spent fuel pool with air cooler and nitrogen injection into reactor containment vessel from portable air separation system for nitrogen generation. As for a water treatment system for handling the radioactive water that had built up in the basement of the turbine building from injected water for cooling fuel debris, it was implemented at first by water treatment equipment from Areva and Kurion and now by Simplified Active Water Retrieve and Recovery System (SARRY) which Toshiba had newly developed as redundant system. Purified water could be reused for circulating injected water for reactor cooling. Strenuous efforts would be made for installation of cover building for fuel removal from spent fuel pool of unit 3 reactor and technology development for fuel debris removal using remote control robots. Portable gamma camera had been developed for decontamination works of radiation 'hot spot'. With loading SARRY on truck, mobile contaminated water treatment and contaminated soil purification system using oxalic acid solution for cesium extraction had been developed to contribute environmental remedial action in surrounding areas. (T. Tanaka)

Off-shore contamination by I-131 and Cs-137 from the Fukushima Daiichi nuclear power station accident

International Nuclear Information System (INIS)

Pereira, Wagner de Souza; Kelecom, Patrick Vicent; Miyashita, Erika; Universidade Federal Fluminense; Kelecom, Alphonse

2011-01-01

On March 11, 2011 the biggest earthquake ever registered in Japan severed off-site power supply to the Fukushima Daiichi Nuclear Power Station. Backup diesel generators began providing electricity to pumps circulating coolant to the reactors, but were knocked out by a large tsunami and the nuclear site lost the ability to maintain proper reactor cooling. This was the beginning of a huge nuclear accident that was assigned an INES maximum rating of 7. On March 21, Japanese authorities reported that the Tokyo Electric Power Company (TEPCO) had detected radioactive materials in seawater. Radioactivity started to be measured by the Japan Atomic Energy Agency every two days in sea water from eight locations, 30km from the coastline. I-131 and Cs-137 were analyzed among other radionuclides. It is the aim of this paper to gather all this information and to discuss the evolution of the radioactive marine contamination during the first month of the accident. Results indicate for surface seawater concentrations ranging from 24.9 to 161.0 Bq/L for I-131 and 11.2 to 186.0 Bq/L for Cs-137, and for deep waters of 1.59-15.0 Bq/L (I-131) and 0.0-11.4 Bq/L (Cs-137). The I-131 concentrations in superficial waters were at or above Japanese regulatory limits in the first days, then lowered during one week to increase again above limits when TEPCO released contaminated water into the ocean, to finally reach not detectable values the last week of April. With the exception of point 4, on April 15, the Cs-137 levels were always well below regulatory limits. (author)

90Sr and 89Sr in seawater off Japan as a consequence of the Fukushima Dai-ichi nuclear accident

Directory of Open Access Journals (Sweden)

N. Casacuberta

2013-06-01

Full Text Available The impact of the earthquake and tsunami on the east coast of Japan on 11 March 2011 caused a loss of power at the Fukushima Dai-ichi nuclear power plant (NPP that resulted in one of the most important releases of artificial radioactivity into the environment. Although several works were devoted to evaluating the atmospheric dispersion of radionuclides, the impact of the discharges to the ocean has been less investigated. Here we evaluate the distribution of Fukushima-derived 90Sr (n = 57 and 89Sr (n = 19 throughout waters 30–600 km offshore in June 2011. Concentrations of 90Sr and 89Sr in both surface waters and shallow profiles ranged from 0.8 ± 0.2 to 85 ± 3 Bq m−3 and from 19 ± 6 to 265 ± 74 Bq m−3, respectively. Because of its short half-life, all measured 89Sr was due to the accident, while the 90Sr concentrations can be compared to the background levels in the Pacific Ocean of about 1.2 Bq m−3. Fukushima-derived radiostrontium was mainly detected north of Kuroshio Current, as this was acting as a southern boundary for transport. The highest activities were associated with near-shore eddies, and larger inventories were found in the closest stations to Fukushima NPP. The data evidence a major influence of direct liquid discharges of radiostrontium compared to the atmospheric deposition. Existing 137Cs data reported from the same samples allowed us to establish a 90Sr / 137Cs ratio of 0.0256 ± 0.0006 in seawater off Fukushima, being significantly different than that of the global atmospheric fallout (i.e., 0.63 and may be used in future studies to track waters coming from the east coast of Japan. Liquid discharges of 90Sr to the ocean were estimated, resulting in an inventory of 53 ± 1 TBq of 90Sr in the inshore study area in June 2011 and total releases of 90Sr ranging from 90 to 900 TBq, depending upon the reported estimates of 137Cs releases that are considered.

Framing the Fukushima Daiichi nuclear accident: An international, comparative study of news frames in Der Spiegel, the Japan Times and the Los Angeles Times

International Nuclear Information System (INIS)

Giannakopoulos, Thanos

2013-01-01

This study investigated into the news frames employed in reporting on the Fukushima Daiichi nuclear accident, explored the maintenance of the radiation reporting standard, and assessed the overall tone for the local government, the Japanese Government, and the IAEA. Based on content from Der Spiegel, the Japan Times and the Los Angeles Times (n=60), it was found that media evoked 'conflict', 'responsibility attribution', and 'human interest' frames, radiation reporting standard was marginally maintained, and the overall tone was neutral (local government, IAEA) or negative (Japanese Government). Variances across countries were observed, but results coincided with the country's nuclear energy policy. (author)

Impact of Fukushima nuclear disaster on oil-consuming sectors of Japan

OpenAIRE

Taghizadeh-Hesary, Farhad; Yoshino, Naoyuki; Rasoulinezhad, Ehsan

2017-01-01

The Fukushima Daiichi nuclear disaster was an accident at the Fukushima I Nuclear Power Plant in Fukushima, Japan, which resulted primarily from the tsunami following the Tohoku earthquake on 11 March 2011, and which led to year-long nuclear shutdown in the country. During the shutdown, Japan substituted fossil fuels for nuclear power and became more dependent on import and consumption of fossil fuels including oil, gas, and coal. In this paper, we try to shed light on the elasticity of oil c...

137Cs vertical migration in a deciduous forest soil following the Fukushima Dai-ichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Nakanishi, Takahiro; Matsunaga, Takeshi; Koarashi, Jun; Atarashi-Andoh, Mariko

2014-01-01

The large amount of 137 Cs deposited on the forest floor because of the Fukushima Dai-ichi Nuclear Power Plant accident represents a major potential long-term source for mobile 137 Cs. To investigate 137 Cs mobility in forest soils, we investigated the vertical migration of 137 Cs through seepage water, using a lysimetric method. The study was conducted in a deciduous forest soil over a period spanning 2 month to 2 y after the Fukushima nuclear accident. Our observations demonstrated that the major part of 137 Cs in the litter layer moved into the mineral soil within one year after the accident. On the other hand, the topsoil prevented migration of 137 Cs, and only 2% of 137 Cs in the leachate from litter and humus layer penetrated below a 10 cm depth. The annual migration below a 10 cm depth accounted for 0.1% of the total 137 Cs inventory. Therefore, the migration of 137 Cs by seepage water comprised only a very small part of the total 137 Cs inventory in the mineral soil, which was undetectable from the vertical distribution of 137 Cs in the soil profile. In the present and immediate future, most of the 137 Cs deposited on the forest floor will probably remain in the topsoil successively, although a small but certain amount of bioavailable 137 Cs exists in forest surface soil. -- Highlights: • Lysimeter captured 137 Cs mobility in a forest soil after the Fukushima accident. • Major part of 137 Cs in the litter layer moved into the mineral soil within a year. • Litter-leachate 137 Cs was predominantly adsorbed within the topsoil. • The annual migration below a 10 cm depth was 0.1% of the total 137 Cs inventory

Thyroid equivalent doses due to radioiodine-131 intake for evacuees from Fukushima Daiichi Nuclear Power Plant accident

Energy Technology Data Exchange (ETDEWEB)

Tokonami, Shinji; Sorimachi, Atsuyuki; Kashiwakura, Ikuo [Hirosaki University, Institute of Radiation Emergency Medicine, Hirosaki, Aomori (Japan); Hosoda, Masahiro [Hirosaki University, Graduate School of Health Sciences, Hirosaki, Aomori (Japan); Akiba, Suminori [Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima (Japan); Balonov, Mikhail [Protection Laboratory, Institute of Radiation Hygiene, Petersburg (Russian Federation)

2012-11-15

A primary health concern among residents and evacuees in affected areas immediately after a nuclear accident is the internal exposure of the thyroid to radioiodine, particularly I-131, and subsequent thyroid cancer risk. In Japan, the natural disasters of the earthquake and tsunami in March 2011 destroyed an important function of the Fukushima Daiichi Nuclear Power Plant (F1-NPP) and a large amount of radioactive material was released to the environment. Here we report for the first time extensive measurements of the exposure to I-131 revealing I-131 activity in the thyroid of 46 out of the 62 residents and evacuees measured. The median thyroid equivalent dose was estimated to be 4.2 mSv and 3.5 mSv for children and adults, respectively, much smaller than the mean thyroid dose in the Chernobyl accident (490 mSv in evacuees). Maximum thyroid doses for children and adults were 23 mSv and 33 mSv, respectively. (author)

Chernobyl and Fukushima. Similarity and dissimilarity in their cause and outcome

International Nuclear Information System (INIS)

Shibata, Yoshisada

2011-01-01

We compared the two worst nuclear accidents rated INES 7, which occurred at the Chernobyl and the Fukushima Daiichi Nuclear Power Plants. Although the human errors underlie both accidents, the respective causes differed. The accident at Chernobyl was caused by the experiment which resulted in increase in criticality and activity leading to a powerful steam explosion and fire that released a significant fraction of core material into the environment, while that at Fukushima Daiichi was due to the damage to the backup power and containment systems caused by the destructive tsunami waves triggered by the 2011 earthquake off the Pacific coast of Tohoku. The physical health effects of the Chernobyl accident demonstrated so far in general population around Chernobyl are thyroid diseases including cancer in those exposed to the accident in their childhood. The long-term program monitoring for at least 30 years the health conditions of all Fukushima residents will be introduced. (author)

Mutant butterflies discovered at Fukushima

International Nuclear Information System (INIS)

Chauveau, L.

2012-01-01

A Japanese study has shown that malformations are more and more common in butterflies (Zizeeria maha specie) leaving near the damaged nuclear plant of Fukushima Daiichi. A population of 144 butterflies were caught in 10 villages in a radius of 200 km around Fukushima in may 2011, the ratio of malformations was 12.4%. Obvious malformations were withered antennas and wings. In september 2011 a population of 238 butterflies were caught in the same places and the ratio of malformations was then 28.1%. The increase of the malformation ratio could be explained by a cumulative effect of the radiation exposition. In a second experiment, a population of butterflies was caught in a region non-affected by the radioactive contamination and was submitted in laboratory to radiations similar to that of the contamination around Fukushima and similar malformations appeared. The conclusion of the study is that radionuclides released during the Fukushima accident have caused genetic and physiological damages to this butterfly specie. (A.C.)

Fukushima. Five years on - FAQs; 5 Jahre Fukushima - Fragen und Antworten

Energy Technology Data Exchange (ETDEWEB)

NONE

2016-03-15

On 11 March 2011, at 2:46 p.m. local time (6.46 a.m. CET), an earthquake measuring 9 on the Richter scale hit the east coast of Japan. The quake caused a tsunami, with waves as high as 38 metres, which led to large-scale flooding and destruction of roads, the power supply and other infrastructure along Japan's eastern seaboard. The earthquake and tsunami also struck several nuclear power plants. Fukushima Daiichi sustained the worst damage, triggering a chain of events which led to core meltdown, major hydrogen explosions and massive releases of radiation. Below, the Oeko-Institut answers the key questions about the disaster's timeline, latest assessments of the events, and the current situation in Fukushima.

Enhancement of organizational resilience in light of the Fukushima Dai-ichi Nuclear Power Plant accident (4). Consideration of nurturing attitude to achieve the safety-II

International Nuclear Information System (INIS)

Oba, Kyoko; Yoshizawa, Atsufumi; Kitamura, Masaharu

2015-01-01

The Fukushima nuclear plant accident has been examined aiming at clarifying the factors influencing responding which is one of the four cornerstones of resilience engineering. Among the causal factors of responding, such as attitude, skill, health and environment, particular attention has been paid on the role of attitude. In addition, the case of Tokai Dai-ni nuclear plant, which was the success case despite tsunami attack, and the case of Fukushima Dai-ichi nuclear plant have been examined focusing on preparatory actions taken prior to the tsunami attack. Through the comparative examinations, attitudes of several kinds have been identified as key factors contributing to enhance organizational resilience. Moreover, the importance of safety-II concept proposed in conjunction with the methodology of resilience engineering has been clearly exemplified. As a whole, it can be concluded that the methodology of resilience engineering and the concept of safety-II are quite effective when utilized with the structured model. (author)

Strengthening Regulatory Effectiveness in India – Lessons Learnt from Fukushima Accident

International Nuclear Information System (INIS)

Solanki, R.

2016-01-01

Following the Fukushima Daiichi accident in Japan, one of the most important lessons learnt, among other things, was the issue of strengthening the effectiveness of the regulatory bodies. Immediately after the Fukushima accident, National level safety audits were conducted on all operating NPPs in India to review safety of NPPs in India. A national action plan has been prepared to implement the identified short term, midterm and long term measures. The assessment indicates that national response to the Fukushima Accident for safety assessment of NPPs and subsequent actions and initiatives taken for safety enhancement of the NPPs in India are in-line with the objectives of the IAEA Action plan. This paper highlights the actions taken by India in the light of Fukushima Daiichi accident in order to strengthen the regulatory effectiveness through improvements in the existing core processes, challenges faced, Insights gained from the recent initiatives on safety performance indicators and assessment of safety culture, relevant observations of IRRS mission report and Indian perspectives on the further cooperation among the member states for enhancing the regulatory effectiveness for nuclear oversight of regulated organizations. (author)

Effects of indoor and outdoor cultivation conditions on 137 Cs concentrations in cultivated mushrooms produced after the Fukushima Daiichi Nuclear Power Plant accident.

Science.gov (United States)

Tagami, Keiko; Uchida, Shigeo; Ishii, Nobuyoshi

2017-01-01

Radiocesium ( 134 Cs and 137 Cs) in mushrooms has been a matter of public concern after the accident at Fukushima Daiichi Nuclear Power Plant. To minimize the internal dose by ingestion of cultivated mushrooms, the Japanese government set a guideline level with respect to the radiocesium concentration in bed-logs and mushroom beds; however, the effects of indoor and outdoor cultivation methods on radiocesium concentrations in cultivated mushrooms were not clear. The effects of indoor and outdoor cultivation on the radiocesium concentrations in mushroom were examined using published food monitoring data. 137 Cs concentration data in Lentinula edodes from the Aizu area in Fukushima Prefecture and seven prefectures outside Fukushima were used for the analysis. No statistically significant 137 Cs concentration differences were found between these two cultivation methods. Using detected 137 Cs data in shiitake, the geometric means from each prefecture were less than one-quarter of the standard limit (100 Bq kg -1 ) for total radiocesium under both cultivation conditions. It was suspected that re-suspended radiocesium might have been taken up by mushrooms or that radiocesium might have been absorbed into the mushrooms from the soil in the outdoor cultures. However, neither effect was significant for cultivated mushrooms in the areas examined. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Performance of Panasonic ZP-1460 Electronic Personal Dosemeter under Exposure Conditions Likely to be Found at Fukushima Daiichi Nuclear Power Plant

Science.gov (United States)

Tsujimura, Norio; Yoshida, Tadayoshi; Hoshi, Katsuya; Momose, Takumaro

A study on the performance of the Panasonic ZP-1460 electronic personal dosemeter, the model used in the aftermath of the Fukushima Daiichi nuclear power plant accident in March 2011, was conducted under actual exposure situations likely encountered in the plant. The tests pertained to (1) the dose rate response over dose rates >100 mSv/h and (2) the angular response on an anthropomorphic phantom exposed to the rotational and isotropic irradiation geometries. The test results confirmed that the dosemeter provides Hp(10) as a reasonably close estimate of the effective dose for any exposure geometries. The dosemeter response data evaluated in this study can be utilized for converting dosemeter readings to the absorbed dose to any organs and tissues for epidemiologic purposes.

Remediation of radiocesium-contaminated liquid waste, soil, and ash: a mini review since the Fukushima Daiichi Nuclear Power Plant accident.

Science.gov (United States)

Ding, Dahu; Zhang, Zhenya; Lei, Zhongfang; Yang, Yingnan; Cai, Tianming

2016-02-01

The radiation contamination after the Fukushima Daiichi Nuclear Power Plant accident attracts considerable concern all over the world. Many countries, areas, and oceans are greatly affected by the emergency situation other than Japan. An effective remediation strategy is in a highly urgent demand. Though plenty of works have been carried out, progressive achievements have not yet been well summarized. Here, we review the recent advances on the remediation of radiocesium-contaminated liquid waste, soil, and ash. The overview of the radiation contamination is firstly given. Afterwards, the current remediation strategies are critically reviewed in terms of the environmental medium. Special attentions are paid on the adsorption/ion exchange and electrically switched ion exchange methods. Finally, the present review outlines the possible works to do for the large-scale application of the novel remediation strategies.

Local area distribution of fallout radionuclides from Fukushima Daiichi Nuclear Power Plant determined by autoradiography analysis

International Nuclear Information System (INIS)

Sakamoto, Fuminori; Ohnuki, Toshihiko; Kozai, Naofumi; Igarashi, Shosuke; Yamasaki, Shinya; Yoshida, Zenko; Tanaka, Shunichi

2012-01-01

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. (author)

Current Status of the Personal Monitoring in Japan After the Fukushima Accident

International Nuclear Information System (INIS)

Koguchi, Y.; Takeuchi, N.; Yamamoto, T.

2013-01-01

On 11 March 2011 Japan suffered a magnitude 9.0 earthquake. The 2011 Great East Japan Earthquake created a series of massive tsunami waves that struck to the east coast of Japan, causing serious damage to Fukushima Daiichi Nuclear Power Plants (NPPs). The radioactive materials such as 134Cs and 137Cs were released into the environment in widespread area of east Japan, especially Fukushima prefecture. Many people living in Fukushima prefecture especially parents of children up to junior high school age have been worrying about the effect of health risk by contaminated radioactive materials. In addition, the International Commission on Radiological Protection (ICRP) has recommended that the dose (effective dose) limits in planned exposure situation for public is 1 mSv in a single year. Therefore, the local governments in Fukushima prefecture have decided to measure the exposed dose using passive dosemeter for public especially children in order to the health risk assessment and the optimum planning of decontamination. The RPL glass dosemeter, we called Glass Badge, based on radiophotoluminescence (RPL) technology is one of suitable dosimeters for the personal monitoring. More than 300 000 Glass Badges were distributed in Fukushima area up to the end of 2012 since the Fukushima Daiichi NPPs accident. It is very easy to know the individual dose and also useful for the health risk assessment.(author)

Measurements using a silicon detector near the Fukushima nuclear plant

International Nuclear Information System (INIS)

Ploc, O.; Uchinori, Yu.; Kitamura, H.

2011-01-01

The massive tsunami hit the Fukushima-Daiichi nuclear power plant after the Tohoku earthquake on March 11 th , 2011. Emergency electric systems of diesel electric machines stopped and during several days later the hydrogen exploded due to over-heated reactors at units 1, 3 and 4. In addition, serious damage was caused in a fuel nuclear storage of unit 2. As a result of these accidents, an extremely large amount of radioisotopes were spread in air, soil, tap water, seawater and food around large areas in East Japan.First, this presentation reports about radiation measurements with the silicon detector Liulin at the J-village, a base of emergency workers, located 20 km from Fukushima Daiichi from March 23 rd , 2011 to August 5 th , 2011. Comparison of measurements with the same device at some other locations (Chiba city, Moscow, board of aircraft) before and after the accident will be presented. Second, the presentation describes our efforts to develop a new portable gamma camera based on Medipix to locate radiation hotspots at Fukushima prefecture. (authors)

Analysis of gamma ray intensity on the S/C vent pipes area in the unit 2 reactor building of the Fukushima Daiichi Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Cho, Jai Wan; Choi, Young Soo; Jeong, Kyung Min [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

The robot is equipped with cameras, a dosimeter, and 2 DOF (degree of freedom) manipulation arms. It loads a small vehicle equipped with a camera that can access and inspect narrow areas. TEPCO is using the four-legged walking robot to inspect the suppression chamber (S/C) area of the unit 2 reactor building basement in the Fukushima Daiichi Nuclear Power Plant. The robot carried out 6 missions for about four months, from 11 December, 2012 to 15 March, 2013, where it examined an evidence of a leakage of radioactivity contaminated water in the S/C area of unit 2 reactor building. When a camera's signal processing unit, which is consist of ASIC and FPGA devices manufactured by a CMOS fabrication process, is exposed to a higher dose rate gamma ray, the speckle distribution in the camera image increase more. From the inspection videos, released by TEPCO, of the underground 8 vent pipes in the unit 2 reactor building, we analyzed the speckle distribution from the high dose-rate gamma rays. Based on the distribution of the speckle, we attempted to characterize the vent pipe with much radioactivity contaminated materials among the eight vent pipes connected to the PCV. The numbers of speckles viewed in the image of a CCD (or CMOS) camera are related to an intensity of the gamma ray energy emitted by a nuclear fission reaction from radioactivity materials. The numbers of speckles generated by gamma ray irradiation in the camera image are calculated by an image processing technique. Therefore, calculating the speckles counts, we can determine the vent pipe with relatively most radioactivity-contaminated materials among the other vent pipes. From the comparison of speckles counts calculated in the inspection image of the vent pipe with the speckles counts extracted by gamma ray irradiation experiment of the same small vehicle camera model loaded with the four-legged walking robot, we can qualitatively estimate the gamma ray dose-rate in the S/C vent pipe area of the

EU Nuclear vs. Fukushima

International Nuclear Information System (INIS)

Poncelet, Jean-Pol

2011-01-01

Conclusions: • The Fukushima-Daiichi accident represents an opportunity for the nuclear industry to demonstrate its ability to learn from experience through “a continuous improvement strategy”; • Inside the EU: which legal framework for nuclear safety - harmonisation of licensing procedures - EU-level reactor design clearance?; • No way forward without public support: how to address, explain, convince?; • Greater cooperation between industry and international organizations: FORATOM available to contribute

Fukushima Daiichi - Human and organizational facts - Part 1: The events and the organizations which worked in controlling the incident

International Nuclear Information System (INIS)

2012-01-01

After the Fukushima Daiichi accident on March 11 th , 2011, the Swiss Federal Nuclear Safety Inspectorate (ENSI) conducted various analyses in order to understand the sequence of events and the contributing factors from both a human as well as an organizational point of view. This analysis considers reports published by TEPCO, the operator of the Fukushima power plants, the Japanese Authorities and IAEA. The deepening of the analysis of the human and organizational aspects became necessary as the accident and its causes are very complex. This complexity is not only the result of technical aspects, but it is also due to the interactions between technical, organizational and human aspects. It is to be considered that additional analyses will be required to exactly understand the physical, organizational and human processes involved. One has to keep in mind the tremendous dimension of the earthquake and the tsunami, as well as the courage and devotedness shown by the actors involved, especially the workers of the Fukushima plants. They had to treat the dramatic issues of the accident, which hit three reactor blocks, and they had to react on the spot to the catastrophic situation with many subsequent earthquakes and, sometimes, without news about their own families. It is necessary to understand the organizational weaknesses with respect to the protection of the plant against the danger of a very large tsunami and the management of a serious accident, in order to learn the necessary lessons. The weaknesses can only be explained by a thorough analysis of the situation which, at the same time, takes the technical environment into account as well as organizational aspects of the accident. The present report considers important event data which are necessary for the understanding of the situation that the various organizations and persons had to master. The role of the organizations in Tokyo and in the Fukushima prefecture is also analyzed. The Fukushima accident is the

Linear free energy correlations for fission product release from the Fukushima-Daiichi nuclear accident.

Science.gov (United States)

Abrecht, David G; Schwantes, Jon M

2015-03-03

This paper extends the preliminary linear free energy correlations for radionuclide release performed by Schwantes et al., following the Fukushima-Daiichi Nuclear Power Plant accident. Through evaluations of the molar fractionations of radionuclides deposited in the soil relative to modeled radionuclide inventories, we confirm the initial source of the radionuclides to the environment to be from active reactors rather than the spent fuel pool. Linear correlations of the form In χ = −α ((ΔGrxn°(TC))/(RTC)) + β were obtained between the deposited concentrations, and the reduction potentials of the fission product oxide species using multiple reduction schemes to calculate ΔG°rxn (TC). These models allowed an estimate of the upper bound for the reactor temperatures of TC between 2015 and 2060 K, providing insight into the limiting factors to vaporization and release of fission products during the reactor accident. Estimates of the release of medium-lived fission products 90Sr, 121mSn, 147Pm, 144Ce, 152Eu, 154Eu, 155Eu, and 151Sm through atmospheric venting during the first month following the accident were obtained, indicating that large quantities of 90Sr and radioactive lanthanides were likely to remain in the damaged reactor cores.

Crisis communication at NPP-Fukushima 1 accident

International Nuclear Information System (INIS)

Tsuchida, S.

2012-01-01

The crisis communication at the TEPCO Fukushima Daiichi Nuclear Power Plant accident in the disaster 3.11 was examined. I discussed the nature of crisis communication which is information exchange between the persons responsible to the accident and the public. And Myth of Panic and Elite Panic were also discussed. (author)

Estimation of absorbed radiation dose rates in wild rodents inhabiting a site severely contaminated by the Fukushima Dai-ichi nuclear power plant accident.

Science.gov (United States)

Kubota, Yoshihisa; Takahashi, Hiroyuki; Watanabe, Yoshito; Fuma, Shoichi; Kawaguchi, Isao; Aoki, Masanari; Kubota, Masahide; Furuhata, Yoshiaki; Shigemura, Yusaku; Yamada, Fumio; Ishikawa, Takahiro; Obara, Satoshi; Yoshida, Satoshi

2015-04-01

The dose rates of radiation absorbed by wild rodents inhabiting a site severely contaminated by the Fukushima Dai-ichi Nuclear Power Plant accident were estimated. The large Japanese field mouse (Apodemus speciosus), also called the wood mouse, was the major rodent species captured in the sampling area, although other species of rodents, such as small field mice (Apodemus argenteus) and Japanese grass voles (Microtus montebelli), were also collected. The external exposure of rodents calculated from the activity concentrations of radiocesium ((134)Cs and (137)Cs) in litter and soil samples using the ERICA (Environmental Risk from Ionizing Contaminants: Assessment and Management) tool under the assumption that radionuclides existed as the infinite plane isotropic source was almost the same as those measured directly with glass dosimeters embedded in rodent abdomens. Our findings suggest that the ERICA tool is useful for estimating external dose rates to small animals inhabiting forest floors; however, the estimated dose rates showed large standard deviations. This could be an indication of the inhomogeneous distribution of radionuclides in the sampled litter and soil. There was a 50-fold difference between minimum and maximum whole-body activity concentrations measured in rodents at the time of capture. The radionuclides retained in rodents after capture decreased exponentially over time. Regression equations indicated that the biological half-life of radiocesium after capture was 3.31 d. At the time of capture, the lowest activity concentration was measured in the lung and was approximately half of the highest concentration measured in the mixture of muscle and bone. The average internal absorbed dose rate was markedly smaller than the average external dose rate (sampling area was estimated to be approximately 52 μGy h(-1) (1.2 mGy d(-1)), even 3 years after the accident. This dose rate exceeds 0.1-1 mGy d(-1) derived consideration reference level for Reference rat

Decision no. 2011-DC-0218 of the French nuclear safety authority from May 5, 2011, ordering the EURODIF SA company to proceed to a complementary safety evaluation of some of its basic nuclear facilities in the eyes of the Fukushima Daiichi nuclear power plant accident

International Nuclear Information System (INIS)

2011-01-01

As a consequence of the accident of the Fukushima Daiichi nuclear power plant (Japan), the French Prime Minister entrusted the French nuclear safety authority (ASN) with the mission to carry out a safety analysis re-evaluation of the French nuclear facilities, and in particular the nuclear power plants. A decision has been addressed by the ASN to each nuclear operator with the specifications of this safety re-evaluation analysis and the list of facilities in concern. This document is the decision addressed to the EURODIF SA company, operator of the George Besse I uranium enrichment plant of the Tricastin site (France). (J.S.)

Decision no. 2011-DC-0219 of the French nuclear safety authority from May 5, 2011, ordering the SOCATRI company to proceed to a complementary safety evaluation of some of its basic nuclear facilities in the eyes of the Fukushima Daiichi nuclear power plant accident

International Nuclear Information System (INIS)

2011-01-01

As a consequence of the accident of the Fukushima Daiichi nuclear power plant (Japan), the French Prime Minister entrusted the French nuclear safety authority (ASN) with the mission to carry out a safety analysis re-evaluation of the French nuclear facilities, and in particular the nuclear power plants. A decision has been addressed by the ASN to each nuclear operator with the specifications of this safety re-evaluation analysis and the list of facilities in concern. This document is the decision addressed to the SOCATRI company, operator of the nuclear dismantling and waste processing plants of the Tricastin site (France). (J.S.)

Observation of fallout deposition in an outdoor swimming pool 50 km away from the Fukushima Daiichi nuclear power plant

International Nuclear Information System (INIS)

Saegusa, Jun; Yasuda, Ryo; Kurikami, Hiroshi

2014-01-01

After the accident at the Fukushima Daiichi nuclear power plant (NPP), outdoor school swimming pools at Fukushima were decontaminated to curb the redistribution of radioactivity into downstream farmlands. In the process, the radioactivity concentrations of the pool water and sediment substances (residue) were measured to estimate the deposition density of the fallout. At a pool situated 50 km away from the NPP, the average concentrations of radiocesium ( 134+137 Cs) for the water and residue were quantified as 170 Bq L −1 and 3.6 × 10 5 Bq kg −1 , respectively. Taking account of the radioactivity concentrations and of the water balance in and around the pool, the deposition density of radiocesium, as of August 2011, was precisely determined to be 0.32 ± 0.03 MBq m −2 (k = 1). The density corroborated the previous results obtained by other methods, i.e., airborne surveys, in-situ Ge surveys and soil samplings at neighboring locations. Other than radiocesium, the only gamma-emitting nuclide detected was 110m Ag, with a concentration of 560 Bq kg −1 in the residue. The radioactivity concentrations of 89 Sr, 90 Sr, 238 Pu and 239+240 Pu in the water were all less than the minimum detectable activities – 2, 0.1, 0.002 and 0.002 Bq L −1 , respectively. - Highlights: • Deposition density of radiocesium was estimated at a swimming pool in Fukushima. • The density was determined with a small standard uncertainty of approximately 10%. • Water balance was simulated for estimating radioactivity budget in the pool. • Detected gamma-emitting nuclide was 110m Ag other than radiocesium. • Radiocesium was much dominant compared with 89 Sr, 90 Sr, 110m Ag, 238 Pu and 239+240 Pu

Impact on the marine environment of radioactive releases resulting from the Fukushima-Daiichi nuclear accident. April 4, 2011

International Nuclear Information System (INIS)

2011-01-01

After having outlined that measurements taken over several days in the sea water in the vicinity of the power station have revealed severe contamination of the marine environment by various radionuclides released as a result of the accident at the Fukushima-Daiichi nuclear power station, this report describes the origins of the contamination of the marine environment (release of liquid effluents directly into the sea in the vicinity of the damaged reactors, atmospheric fallout onto the surface of the sea, conveyance of radioactive pollution by rainout of contaminated ground). Then, while proposing several maps, the authors analyse and comment the dispersion in the sea of radioactive pollutants by addressing the following issues: topography of the sea bed and sea currents off the Japanese coast, immediate or short term dispersion (a few days), mid-term dispersion (weeks and months), long term and large scale future of the radioactive pollutants. Finally, the report briefly discusses the impact of radioactive pollution on living species

Fukushima, 4 years after. Proceedings of the technical day

International Nuclear Information System (INIS)

Champion, Didier; Charles, Thierry; Renaud, Philippe; Fievet, Bruno; Besnus, Francois; Tichauer, Michael; Lecomte, Jean-Francois; Lebaron-Jacobs, Laurence; Menetrier, Florence; Piroux, Jean-Christophe; Schneider, Thierry; Godet, Jean-Luc

2015-03-01

Three years after the 2012 meeting of the French Society of Radiation Protection (SFRP) devoted to the Fukushima accident, the SFRP organized a new technical meeting to take stock of the actual situation in Japan. The program comprises 5 topical sessions dealing with: the accident, the status of the facility and its fate, the terrestrial and marine environmental impacts, the human health impacts and the preventive actions, the remedial actions in contaminated territories, and the post-accident management of territories, populations and foodstuffs. This document brings together the abstracts and the presentations (slides) of the different talks given at the meeting: 1 - The Chernobyl and Fukushima accidents: common points and differences (Didier CHAMPION, SFRP); 2 - Fukushima Dai-ichi: present day situation and fate of the facilities (Thierry CHARLES, IRSN); 3 - The Fukushima accident impact on the terrestrial environment and the related doses (Philippe RENAUD, IRSN); 4 - The Fukushima accident impact on the marine environment (Bruno FIEVET, IRSN); 5 - Short-term health effects and implementation of the long-term population monitoring (Laurence LEBARON-JACOBS, CEA); 6 - Radiations and thyroid cancer risk (Florence MENETRIER, CEA); 7 - Decontamination wastes management (Francois BESNUS, IRSN); 8 - Solutions offered by Areva for the cleansing of the Fukushima site (Jean-Christophe PIROUX, AREVA); 9 - Questions about wastes management in post-accident situation (Michael TICHAUER, IRSN); 10 - Experts involvement to the population (Thierry SCHNEIDER, CEPN); 11 - Management of local foodstuffs (Jean-Francois LECOMTE, IRSN); 12 - Lessons learnt at the national and international scale (Jean-Luc GODET, ASN)

What nuclear industry after Fukushima?

International Nuclear Information System (INIS)

Barre, Bertrand

2011-01-01

Nuclear power experienced a fast growth during the 70's and 80's, but a quasi-stagnation during the 90's. Since the beginning of the 21. century, a so-called renaissance could be witnessed, fuelled by concerns about energy security of supply, volatility of oil and gas prices, fear of an incoming 'peak oil', and, last but not least, the threat of global climate change due to the anthropogenic emissions of greenhouse effect gases. Then, on March 11 2011, a monster earthquake followed by a violent tsunami triggered an accident which all but destroyed four nuclear reactors on the Fukushima-Daiichi site, on the east coast of Honshu, the main Japanese island. There was meltdown in three reactor cores, hydrogen explosions which blew off the upper structures of four reactor buildings, and massive radioactive contamination of a spread of land north-west of the site as well as radioactive releases to the ocean. This accident triggered reactions of various intensities throughout the world, awakening the fears, and questions raised 25 years before by the Chernobyl accident. But the tsunami did not make the fundamentals of the renaissance disappear. After a pause, to fully learn lessons from the accident, the renaissance is likely to start again, all the much since the 'third generation' nuclear plants would have survived unscathed the Fukushima earthquake and tsunami. (author)

Long-term outcomes of patients evacuated from hospitals near the Fukushima Daiichi nuclear power plant after the Great East Japan Earthquake.

Science.gov (United States)

Igarashi, Yutaka; Tagami, Takashi; Hagiwara, Jun; Kanaya, Takahiro; Kido, Norihiro; Omura, Mariko; Tosa, Ryoichi; Yokota, Hiroyuki

2018-01-01

After the accident of the Fukushima Daiichi nuclear power plant due to the Great East Japan Earthquake in March 2011, the Japanese government issued a mandatory evacuation order for people living within a 20 km radius of the nuclear power plant. The aim of the current study was to investigate long-term outcomes of these patients and identify factors related to mortality. Patients who were evacuated from hospitals near the Fukushima Daiichi nuclear power plant to the Aizu Chuo Hospital from 15 to 26 March, 2011 were included in this study. The following data were collected from medical records: age, sex, activities of daily life, hospital they were admitted in at the time of earthquake, distance between the facility and the nuclear power plant, reasons of evacuation and number of transfers. The patient outcomes were collected from medical records and/or investigated on the telephone in January 2012. A total of 97 patients (28 men and 69 women) were transferred from 10 hospitals via ambulances or buses. No patients died or experienced exacerbation during transfer. Median age of the patients was 86 years. Of the total, 36 patients were not able to obey commands, 44 were bed-ridden and 61 were unable to sustain themselves via oral intake of food. Among 86 patients who were followed-up, 41 (48%) died at the end of 2011. Multiple-regression analysis showed that non-oral intake [Hazard Ratio (HR): 6.07, 95% Confidence interval (CI): 1.94-19.0] and male sex [HR: 8.35, 95% CI: 2.14-32.5] had significant impact on mortality. This study found that 48% of the evacuated patients died 9 months after the earthquake and they had significantly higher mortality rate than the nursing home residents. Non-oral intake and male sex had significant impact on mortality. These patients should be considered as especially vulnerable in case of hospital evacuation.

Gene expression analyses of the small intestine of pigs in the ex-evacuation zone of the Fukushima Daiichi Nuclear Power Plant.

Science.gov (United States)

Morimoto, Motoko; Kato, Ayaka; Kobayashi, Jin; Okuda, Kei; Kuwahara, Yoshikazu; Kino, Yasushi; Abe, Yasuyuki; Sekine, Tsutomu; Fukuda, Tomokazu; Isogai, Emiko; Fukumoto, Manabu

2017-11-15

After the accident at the Fukushima Daiichi Nuclear Power Plant, radioactive contaminants were released over a widespread area. Monitoring the biological effects of radiation exposure in animals in the ex-evacuation zone should be continued to understand the health effects of radiation exposure in humans. The present study aimed to clarify the effects of radiation by investigating whether there is any alteration in the morphology and gene expressions of immune molecules in the intestine of pigs and inobuta (wild boar and domestic pig hybrid) in the ex-evacuation zone in 2012. Gene expression analysis was performed in small intestine samples from pigs, which were collected from January to February 2012, in the ex-evacuation zone. Pigs lived freely in this zone, and their small intestine was considered to be affected by the dietary intake of radioactive contaminants. Several genes were selected by microarray analysis for further investigation using real-time polymerase chain reaction. IFN-γ, which is an important inflammatory cytokine, and TLR3, which is a pattern recognize receptor for innate immune system genes, were highly elevated in these pigs. The expressions of the genes of these proteins were associated with the radiation level in the muscles. We also examined the alteration of gene expressions in wild boars 5 years after the disaster. The expression of IFN-γ and TLR3 remained high, and that of Cyclin G1, which is important in the cell cycle, was elevated. We demonstrated that some changes in gene expression occurred in the small intestine of animals in the ex-evacuation zone after radiation. It is difficult to conclude that these alterations are caused by only artificial radionuclides from the Fukushima Daiichi Nuclear Power Plant. However, the animals in the ex-evacuation zone might have experienced some changes owing to radioactive materials, including contaminated soil, small animals, and insects. We need to continue monitoring the effects of long

Radioactive Cs in the Severely Contaminated Soils Near the Fukushima Daiichi Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Kaneko, Makoto; Iwata, Hajime; Shiotsu, Hiroyuki; Masaki, Shota; Kawamoto, Yuji; Yamasaki, Shinya; Nakamatsu, Yuki; Imoto, Junpei; Furuki, Genki; Ochiai, Asumi [Department of Chemistry, Kyushu University, Fukuoka (Japan); Nanba, Kenji [Department of Environmental Management, Faculty of Symbiotic System Science, Fukushima University, Fukushima (Japan); Ohnuki, Toshihiko [Advanced Science Research Center Japan Atomic Energy Agency, Tokai (Japan); Ewing, Rodney C. [Department of Geological Sciences, Center for International Security and Cooperation, Stanford University, Stanford, CA (United States); Utsunomiya, Satoshi, E-mail: utsunomiya.satoshi.998@m.kyushu-u.ac.jp [Department of Chemistry, Kyushu University, Fukuoka (Japan)

2015-09-01

Radioactive Cs isotopes ({sup 137}Cs, t{sub 1/2} = 30.07 years and {sup 134}Cs, t{sub 1/2} = 2.062 years) occur in severely contaminated soils within a few kilometer of the Fukushima Daiichi nuclear power plant at concentrations that range from 4 × 10{sup 5} to 5 × 10{sup 7} Bq/kg. In order to understand the mobility of Cs in these soils, both bulk and submicron-sized particles elutriated from four surface soils have been investigated using a variety of analytical techniques, including powder X-ray diffraction analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and analysis of the amount of radioactivity in sequential chemical extractions. Major minerals in bulk soil samples were quartz, feldspar, and minor clays. The submicron-sized particles elutriated from the same soil consist mainly of mica, vermiculite, and smectite and occasional gibbsite. Autoradiography in conjunction with SEM analysis confirmed the association of radioactive Cs mainly with the submicron-sized particles. Up to ~3 MBq/kg of {sup 137}Cs are associated with the colloidal size fraction (<1 μm), which accounts for ~78% of the total radioactivity. Sequential extraction of the bulk sample revealed that most Cs was retained in the residual fraction, confirming the high binding affinity of Cs to clays, aluminosilicate sheet structures. The chemistry of the fraction containing submicron-sized particles from the same bulk sample showed a similar distribution to that of the bulk sample, again confirming that the Cs is predominantly adsorbed onto submicron-sized sheet aluminosilicates, even in the bulk soil samples. Despite the very small particle size, aggregation of the particles prevents migration in the vertical direction, resulting in the retention of >98% of Cs within top ~5 cm of the soil. These results suggest that the mobility of the aggregates of submicron-sized sheet aluminosilicate in the surface environment is a key factor controlling the current Cs

Secular distribution of radioactive concentration in the atmosphere at Fukushima, Hitachi and Marumori

International Nuclear Information System (INIS)

Zhang, ZiJian; Kakitani, Shunsuke; Ninomiya, Kazuhiko; Takahashi, Naruto; Shinohara, Atsushi; Yamaguchi, Yoshiaki; Yoshimura, Takashi; Kita, Kazuyuki; Watanabe, Akira

2013-01-01

Our group started gamma ray measurement of air dust sample after the Fukushima Dai-ichi nuclear power station accident. Air dust filters was collected at Hitachi, Fukushima and Marumori. The activity of Cs-134 and Cs-137 was determined by germanium semiconductor detector. The radiocesium activity concentration in air dust(Bq/m"3) after October 2011 were stable and 6.2×10"-"6 at Hitachi, 3.0×10"-"4 at Fukushima and 1.3×10"-"4 at Marumori. (author)

Decontamination work in the area surrounding Fukushima Dai-ichi Nuclear Power Plant: another occupational health challenge of the nuclear disaster.

Science.gov (United States)

Wada, Koji; Yoshikawa, Toru; Murata, Masaru

2012-01-01

This article describes occupational health measures for workers involved in decontamination of radioactive material discharged around Fukushima Dai-ichi Nuclear Power Plant after the explosions in 2011. Decontamination is performed by removing radioactive particles (mainly cesium) from surfaces of soil, grass and trees, and buildings. Measurement of radiation doses is necessary to reduce exposure, and to determine whether workers can work below dose limits. Protective equipment for decontamination is determined based on the concentration of radiation in contaminated soil and the exposure to dust. Health examinations by physicians are mandated for decontamination workers upon hiring and every 6 months. While there is no possibility of acute radiation injury from decontamination, workers may be anxious about the unclear effects of chronic low level radiation exposure on health. Measures to protect the decontamination workers are the top priority.

The accident in Fukushima. Preliminary report on the accident progress in the nuclear power plants as a consequence of the earth quake on 11th March 2011; Der Unfall in Fukushima. Zwischenbericht zu den Ablaeufen in den Kernkraftwerken nach dem Erdbeben vom 11. Maerz 2011

Energy Technology Data Exchange (ETDEWEB)

Borghoff, Stefan; Brueck, Benjamin; Kilian-Huelsmeyer, Yvonne; Maqua, Michael; Mildenberger, Oliver; Quester, Claudia; Stahl, Thorsten; Thuma, Gernot; Wetzel, Norbert; Wild, Volker

2011-08-15

The preliminary report on the accident progress in the nuclear power plants as a consequence of the earth quake on 11th March 2011 describes the chronologic sequence of the accident in the different units of the power plant. The measures for mitigation of the accident impact at the site of Fukushima Daiichi and Fukushima Daini included the efforts to reach and maintain stable plant conditions. The issue radiological situation includes an estimation of the air-borne radionuclide release, the contamination of the environment and the sea water, measures for protection of the public. The lessons learned following the NISA and IAEA fact finding missions and the open questions are summarized.

Probabilistic risk assessment (PRA) update in light of the accident at Fukushima Daiichi Nuclear Power Station - 15461

International Nuclear Information System (INIS)

Maeda, K.; Abe, H.; Hirokawa, N.; Satou, C.

2015-01-01

We have performed internal and external event probabilistic risk assessments (PRA) for boiling water reactor power nuclear plants to identify the important accident sequence groups and to evaluate the effectiveness of the additional severe accident measures, regarding to the new regulatory requirements implemented after the accident at Fukushima Daiichi Nuclear Power Station in Japan in 2011. In addition, we will further update our PRA by extracting problems and improvements from the current PRA, by catching up the state-of-the-art knowledge, modern PRA methodologies in order to contribute voluntarily to safety improvement as well as to comply with regulations. In this document, prior to the extensive PRA updates, we would describe technical contents and qualitative results about PRA updates that have been performed preliminary so far, especially about the external event (seismic) PRA and how to model the additionally deployed severe accident measures (e.g. power supply car, fire engine) so that they can be function external hazards, such as component failure rate of equipment, human reliability 'out of control room', and mission time extension. (authors)

Continuing 137 Cs release to the sea from the Fukushima Dai-ichi Nuclear Power Plant through 2012

Directory of Open Access Journals (Sweden)

J. Kanda

2013-09-01

Full Text Available The rate of cesium-137 (137Cs release to the sea from the Fukushima Dai-ichi Nuclear Power Plant for the period until September 2012 was estimated. Publicly released data on 137Cs radioactivity in seawater near the power plant by Tokyo Electric Power Company strongly suggest a continuing release of radionuclides to the sea. The plant has an artificial harbour facility, and the exchange rate of harbour water with surrounding seawater was estimated by the decrease in radioactivity immediately after an intense radioactive water release. The estimated exchange rate of water in the harbour was 0.44 d−1 during the period from 6 to 19 April. The 137Cs radioactivity in the harbour water was substantially higher than that of seawater outside and remained relatively stable after June 2011. A quasi-steady state was assumed with continuous water exchange, and the average release rate of 137Cs was estimated to be 93 GBq d−1 in summer 2011 and 8.1 GBq d−1 in summer 2012.

A study based on Fukushima Daiichi nuclear disaster

International Nuclear Information System (INIS)

Oki, Naotaka

2012-01-01

It consists of three chapters that the first chapter is the important policy issues to be confirmed after the Fukushima nuclear disaster, the second about Hamaoka Nuclear Power Plant, and the third other problems. The first chapter discussed that 1) was it necessary for us to revise the nuclear regulation system for recovering of trust on nuclear safety?, 2) an approach to solve high level radioactive waste disposal sites, 3) the government gave the suitable decisions on the basis of conclusions of authorities for security of nuclear power, and 4) expecting for construction of nuclear safety regulation system. The second chapter stated on Hamaoka Nuclear Power Plant; 1) actions for security control measures, and 2) Shizuoka prefecture's affairs. The third, 1) verification of the unanticipated situation and importance of empowerment faculty and sensitivity in practice, 2) the trend of public opinion on reopening of nuclear power plant, 3) it is necessary to pay special attention to issues expected for nuclear safety regulation system in Japan, and 4) importance of approach to the trend of public opinion. (S.Y.)

Radiocesium contamination of the web spider Nephila clavata (Nephilidae: Arachnida) 1.5 years after the Fukushima Dai-ichi Nuclear Power Plant accident.

Science.gov (United States)

Ayabe, Yoshiko; Kanasashi, Tsutomu; Hijii, Naoki; Takenaka, Chisato

2014-01-01

We measured the concentrations of radiocesium ((134)Cs and (137)Cs) in a large web spider, Nephila clavata L. Koch (Nephilidae: Arachnida), collected at three sites at different distances from the Fukushima Dai-ichi Nuclear Power Plant about 1.5 y after the accident in March 2011. The radiocesium concentrations in spiders were highest in a streamside secondary forest 33 km northwest of the power plant: mean ± a standard deviation of 2.401 ± 1.197 Bq g(-1) dry for (134)Cs and 3.955 ± 1.756 Bq g(-1) dry for (137)Cs. In a hillside secondary forest 37 km northwest of the power plant, the mean concentrations of (134)Cs and (137)Cs were 0.825 ± 0.247 Bq g(-1) dry and 1.470 ± 0.454 Bq g(-1) dry, respectively. In a pine forest 62 km west of the power plant, very low radiocesium concentrations were detected, but in only a few individuals. The concentrations of (134)Cs and (137)Cs in spiders collected at each site tended to be correlated with the air radiation dose rate at each site. Since spiders are key components of food webs in forests, the high concentrations in this species at contaminated sites suggested that the radiocesium from the accident has transferred through food chains and reached to higher trophic level of the food chains. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Fukushima. The accident sequence and important causes. Pt. 2/3; Fukushima. Unfallablauf und wesentliche Ursachen. T. 2/3

Energy Technology Data Exchange (ETDEWEB)

Pistner, Christoph [Oeko-Institut e.V., Darmstadt (Germany). Bereich Nukleartechnik und Anlagensicherheit

2013-07-01

In this part on the accident sequence in the NPP Fukushima Daiichi on March 11, 2011 the important safety systems of a nuclear power plant are described, including the design of a nuclear boiling water reactor with Mark-II type containment, the high-pressure injection system and the systems for afterheat removal. The chronology of the accident progress in the NPP units 1-3 is described. The units 4-6 were shutdown due to revision work. Due to the earthquake an electric power transformation station close to the NPP site and the power poles were destroyed, the redundant power supply of the neighboring electricity supplier Tohoku did not work. All emergency diesel generators were flooded and destroyed resulting in the so-called station blackout. Firefighting trucks and materials for radiation protection and the infrastructure at the NPP site were destroyed. The release of radioactivity induced a severe contamination of the reactor site.

Activities of the interactive public meetings on radiation and its health effect after the TEPCO Fukushima Daiichi Nuclear Power Station accident in the case of Nuclear Fuel Cycle Engineering Laboratories

International Nuclear Information System (INIS)

Sugiyama, Kenji; Ayame, Junko; Takashita, Hirofumi; Yamamoto, Ryuuichi

2016-02-01

Radioactive materials were widely released into the environment during the TEPCO Fukushima Daiichi Nuclear Power Station accident (hereinafter referred to as the Fukushima nuclear accident), which increased residents' fear of radiation and its health effects on their bodies. Japan Atomic Energy Agency (JAEA) has held public meetings on radiation and its health effects mainly for parents of students in kindergartens, elementary schools, and junior high schools in Fukushima prefecture after the Fukushima nuclear accident. These meetings are held based on our experience of practicing risk communication activities for a decade in JAEA with local residents. Questionnaires were collected after the meetings. The contents of the questionnaire are degree of understanding about the contents of the meetings, anxiety or worry items, opportunity of obtaining radiation and nuclear information before the accident, and some opinions and requests. By analyzing questionnaires, we confirmed that interactive communication is effective in increasing participants' understanding and in decreasing their anxiety. Risk communication study office supported the staff members of the meetings providing information such as participants' questions in the past meetings. To provide information, we made a homepage and held the orientation for the staff members. Questionnaires of the staff members were also collected and analyzed after the public meetings. (author)

The impact of the Fukushima nuclear accident on European energy policy

International Nuclear Information System (INIS)

Wittneben, Bettina B.F.

2012-01-01

The disaster that struck the Fukushima Daiichi nuclear plant in Japan has reignited the international debate on the future of nuclear energy. Interestingly, the incident has been used to both justify nuclear power generation and reconsider past decisions made on established or planned nuclear power sites. Geographically removed from the radioactive fallout, Europe's response to the massive nuclear accident differed greatly among the member states. The UK and Germany stand out as examples of the wide spread of policy response to the Fukushima Daiichi nuclear accident. In the UK, policy makers remained firm on their decision to increase nuclear power generation in the near future, whereas in Germany, the federal government decided to at least temporarily shut down the old generation of nuclear reactors and re-examine the safety of all national nuclear power facilities. Furthermore, a regional voter backlash, fuelled by resentment of the Merkel government's previous commitment to nuclear power, dealt a serious blow to the ruling coalition parties. How can national policy responses to the same event be so divergent in two European countries? This article attempts to answer this question in five arguments. I argue that in contrast to the UK, the German public faced imminent elections, stronger media reporting, increasing trust in renewable technologies, a history of nuclear resistance and a feeling of close cultural proximity to the Japanese.

Assessment of Nutritional Status of Iodine Through Urinary Iodine Screening Among Local Children and Adolescents After the Fukushima Daiichi Nuclear Power Plant Accident.

Science.gov (United States)

Tsubokura, Masaharu; Nomura, Shuhei; Watanobe, Hajime; Nishikawa, Yoshitaka; Suzuki, Chiaki; Ochi, Sae; Leppold, Claire; Kinoshita, Hirokatsu; Kato, Shigeaki; Saito, Yasutoshi

2016-12-01

Iodine deficiency is an important modifier of the risk of thyroid cancer following irradiation. However, little information is available on the prevalence of iodine deficiency in Fukushima and its surroundings after the Fukushima Daiichi nuclear power plant accident that occurred in March 2011. In order to assess urinary iodine concentrations (UIC) and the prevalence of iodine deficiency and to elucidate any associations between demographic characteristics and UIC levels among children and adolescents aged ≤18 years at the time of the accident in Fukushima Prefecture and its surroundings, the data on voluntary UIC testing conducted by Hirata Central Hospital, Fukushima, were evaluated. A total of 4410 children and adolescents with a median age of 10 years at examination underwent UIC testing between October 2012 and October 2015. Calculated for all the participants, the median UIC level was 204 μg/L (range 25-21,100 μg/L). There were 133 (3.0%), 732 (16.6%), and 1472 (33.4%) participants with UIC levels of nutritional iodine status, no participants were severely iodine deficient (<20 μg/L), but 16.6% of the population were mildly (50-100 μg/L) or moderately (20-50 μg/L) iodine deficient. While no significant difference in UIC was noted between those who did and did not increase dietary iodine intake after the accident (p = 0.93), there were significant differences by year (p < 0.01), school level (p < 0.001), and residential area at the time of the accident (p < 0.001). This study demonstrates that the children and adolescents examined had a sufficient amount of iodine during the period 1.5-4.5 years after the nuclear accident. In addition to the differences in the scale and the countermeasures undertaken between the Fukushima and Chernobyl accidents, differences in dietary iodine intake might have played an additional role in resulting in the reportedly different radiation doses to the thyroid between the two nuclear accidents.

Beyond design basis external flooding. Generic design assessment and lessons learned from the Fukushima Dai-ichi accident

International Nuclear Information System (INIS)

MacLeod, Tanya; Smith, Leslie; Allmark, Tim; Ford, Peter

2017-01-01

New reactors intended for construction in GB undergo the Office for Nuclear Regulation's (ONR's) Generic Design Assessment (GDA). GDA is a pre-licensing process that provides requesting parties with the opportunity to demonstrate at an early stage that the design is capable of meeting the legal requirements of Great Britain. During GDA, the intended reactor site may not yet be known. Therefore, requesting parties usually define a 'Generic Site' with characteristics typical for Great Britain. These characteristics should, as far as possible, bound the characteristics of known potential sites so that reactors of the proposed type could potentially be built at various suitable locations. This paper critically reviews ONR's approach to ensuring that external flooding is appropriately addressed at the GDA stage and covers: An overview of ONR's approach to post-Fukushima assessment. Changes to ONR's SAPs (Safety Assessment Principles) related to External Flooding. Two examples of post-Fukushima GDA approaches to External Flooding. Uncertainty and the provision of adequate safety measures. The paper concludes that the identification of potential vulnerabilities in the design to external flooding combined with a consideration of post-Fukushima resilience enhancements has led to increased regulatory confidence in the robustness of new reactor designs in GB against external flooding. (author)

Simultaneous sampling of indoor and outdoor airborne radioactivity after the Fukushima Daiichi nuclear power plant accident.

Science.gov (United States)

Ishikawa, Tetsuo; Sorimachi, Atsuyuki; Arae, Hideki; Sahoo, Sarata Kumar; Janik, Miroslaw; Hosoda, Masahiro; Tokonami, Shinji

2014-02-18

Several studies have estimated inhalation doses for the public because of the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. Most of them were based on measurement of radioactivity in outdoor air and included the assumption that people stayed outdoors all day. Although this assumption gives a conservative estimate, it is not realistic. The "air decontamination factor" (ratio of indoor to outdoor air radionuclide concentrations) was estimated from simultaneous sampling of radioactivity in both inside and outside air of one building. The building was a workplace and located at the National Institute of Radiological Sciences (NIRS) in Chiba Prefecture, Japan. Aerosol-associated radioactive materials in air were collected onto filters, and the filters were analyzed by γ spectrometry at NIRS. The filter sampling was started on March 15, 2011 and was continued for more than 1 year. Several radionuclides, such as (131)I, (134)Cs, and (137)Cs were found by measuring the filters with a germanium detector. The air decontamination factor was around 0.64 for particulate (131)I and 0.58 for (137)Cs. These values could give implications for the ratio of indoor to outdoor radionuclide concentrations after the FDNPP accident for a similar type of building.

Comparison of direct deposition and root uptake results after the Fukushima Daiichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Tagami, Keiko; Uchida, Shigeo

2012-01-01

Field horsetail(Equisetum arvense) is a kind of fern, and the fertile shoots are eaten as vegetables in Japan in the spring. Since fern species tend to concentrate radiocaesium from soil, concentrations and distribution patterns of radiocaesium in the fertile shoots are of interest. In this study, distribution and food processing results were compared using samples collected in 2011(n=1) and 2012(n=3); the sample collected in 2011 received direct deposition from the Fukushima Daiichi Nuclear Power Plant accident while those collected in 2012 included radiocaesium mainly taken up from soil. About 200-300 shoots were collected at each sampling time. The 137 Cs concentration in samples collected in 2012 decreased by 100-200 times compared to that in 2011. The radiocaesium distribution patterns in strobili, leaves and stems of 2012 samples were almost the same as those of 2011; however, the patterns were different from those of potassium. The radiocaesium removal percentage by food processing (washing + boiling for 2.5min) was 70% in 2011, while that for 2012 samples was 32-72%; the effect of direct deposition and root uptake was not clear. (author)

Robustness of Electrical Systems of Nuclear Power Plants in Light of the Fukushima Daiichi Accident (ROBELSYS). Workshop Proceedings, Paris, France, 1-4 April 2014 - Robustness of Electrical Systems of NPP's in Light of the Fukushima Daiichi Accident. ROBELSYS Workshop Proceedings

International Nuclear Information System (INIS)

2015-01-01

The March 2011 accident at Fukushima Daiichi triggered discussions about the significance of electrical power hazards and their treatment in safety analyses. In order to address these issues and provide relevant conclusions and recommendations to CSNI and CNRA, the Robustness in Electrical Systems (ROBELSYS) Technical Working Group was established in 2012 under the leadership of the Institut de Radioprotection et de Surete Nucleaire (IRSN) of France. The purpose of the ROBELSYS Technical Working Group was to organize an international workshop to identify and discuss the lessons learned from the Fukushima Daiichi accident. The workshop was focused on the provisions taken by various countries concerning national requirements and modifications to the plant designs in order to enhance the robustness of electrical systems, especially the protection against extreme external hazards. The ROBELSYS workshop was held at the OECD Conference Centre in Paris in April 1-4, 2014. A total of 105 participants attended the workshop representing industry and government organisations from 25 countries, as well as international organisations. A total of 34 technical presentations were given in seven sessions as follows: - 1: National Programmes on Evolution of Onsite and Offsite Electric Power Systems; - 2: Role of Electric Power in Severe Accident Management; - 3: Requirements for Robustness of Onsite Electric Power Systems; - 4: Simulation of Transients within NPP Plant Distribution Systems; - 5: Requirements for Equipment Used for Emergency Response; - 6: Margin Assessments for Modern Power Electronics; - 7: Digital Components in Power Systems. Items addressed in the workshop included: - Review of the lessons learned from the Fukushima accident concerning the robustness of electrical systems; - Review of the provisions already taken or planned after the Fukushima accident, regarding the sources, the distribution systems and the loads, and documenting the technical basis for these

Fukushima-Dai-Ichi accident. Information bulletin no. 8 from December 12, 2011; Accident de Fukushima-Dai-Ichi - Bulletin d'information no. 8 du 12 decembre 2011

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-12-12

This news bulletin has been prepared by the French institute of radiation protection and nuclear safety (IRSN) for the information of French residents in Japan. It presents, first, the situation at the date of the bulletin of the food chain contamination in the provinces close to the Fukushima Dai-ichi damaged site, the particular case of rice contamination monitoring and the controls performed at retailer shops. Then, it gives some general recommendations to residents concerning good food consumption and hygiene practices and recommends to avoid any unnecessary travel to the most impacted areas close to the prohibited access area. (J.S.)

Fukushima nuclear accident and the social responsibility of science

International Nuclear Information System (INIS)

Yoshioka, Hitoshi

2011-01-01

Five months had passed since Fukushima Daiichi Nuclear Power Plant (NPP) accident occurred but still there was no knowing when the accident ended. Released radioactivity seemed to be greater than one million terra Bq and if there occurred an explosive rupture of containment vessel due to the failure of containment vent or occurrence of steam explosion, the amount of released radioactivity might amount to be at least equivalent to or surpass that of Chernobyl NPP accident. There existed still a risk that overheating and meltdown of nuclear fuels might reoccur with loss of cooling due to a possible giant aftershock. This article described total views on significant disaster that the accident brought about on many neighboring residents or wide range of people. After a general discussion about what was social responsibility of scientists, social responsibility of scientists for Fukushima Daiichi NPP accident was discussed. Responsibility of omission was also argued. (T. Tanaka)

EC6 safety enhancement - including impact of Fukushima lessons learned

Energy Technology Data Exchange (ETDEWEB)

Yu, S.; Zemdegs, R.; Boyle, S.; Soulard, M., E-mail: stephen.yu@candu.com [Candu Energy Inc., Mississauga, Ontario (Canada)

2012-09-15

The Enhanced CANDU 6 (EC6) is the new Generation III CANDU reactor design that meets the most up to date regulatory requirements and customer expectations. EC6 builds on the proven high performance design inch as the Qinshan CANDU 6 units and has made improvements to safety and operational performance, and has incorporated extensive operational feedback including Fukushima. The Fukushima Dai-ichi March 11, 2011 event has demonstrated the importance of defence-in-depth considerations for beyond-design basis events, including severe accidents. The EC6 design is based on the defence-in-depth principles and provides further design features that address the lessons learned from Fukushima. (author)

Fusion of aerial gamma-ray survey and remote sensing data for a deeper understanding of radionuclide fate after radiological incidents. Examples from the Fukushima Dai-Ichi response

International Nuclear Information System (INIS)

Czaja, Wojciech; Manning, Benjamin; Murphy, J.M.

2016-01-01

We consider fusion of heterogeneous data, consisting of multispectral imagery collected from the WorldView-2 satellite and aerial gamma-ray spectra collected during the NNSA Aerial Measuring System response to the Fukushima Dai-ichi Nuclear Power Plant crisis. These data are analyzed using the non-linear dimension reduction technique of diffusion maps. The data is then used for classification of regions in the scene. A strong spatial coherence is observed in the gamma-ray data that is closely coupled to the underlying terrain classification obtained from the multispectral data, indicating correlation between these a priori uncorrelated measurements. (author)

Variation of radiocesium concentrations in cedar pollen in the Okutama area since the Fukushima Daiichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Tsuruoka, H.; Inoue, K.; Sakano, Y.; Hamada, M.; Shimizu, H.; Fukushi, M.

2015-01-01

Due to releases of radionuclides in the Fukushima Daiichi Nuclear Power Plant accident, radiocesium ( 134 Cs and 137 Cs) has been incorporated into large varieties of plant species and soil types. There is a possibility that radiocesium taken into plants is being diffused by pollen. Radiocesium concentrations in cedar pollen have been measured in Ome City, located in the Okutama area of metropolitan Tokyo, for the past 3 y. In this research, the variation of radiocesium concentrations was analysed by comparing data from 2011 to 2014. Air dose rates at 1 m above the ground surface in Ome City from 2011 to 2014 showed no significant difference. Concentration of 137 Cs contained in the cedar pollen in 2012 was about half that in 2011. Between 2012 and 2014, the concentration decreased by approximately one-fifth, which was similar to the result of a press release distributed by the Japanese Ministry of Agriculture, Forestry and Fisheries. (authors)

CANDU heat sinks improvements as a follow up to Fukushima Daiichi accident ''the regulator perspective''

Energy Technology Data Exchange (ETDEWEB)

Mesmous, Noreddine; Harwood, Chris [Canadian Nuclear Safety Commission, Ottawa, ON (Canada)

2015-06-15

The purpose of this paper is to provide a summary of the Canadian Nuclear Safety Commission (CNSC) recommendations related to improving the heat sink strategy as a follow up to the Fukushima Daiichi Accident (FDA). As a follow up to FDA, CNSC staff tasked the Nuclear Power Plant (NPP) licensees to review the lessons learned from the FDA and re-examine the NPP safety cases. The reviews have examined the CANDU defence-in-depth strategy and considered events more severe than those that have historically been regarded as credible, and evaluated their impact on the NPPs safety. Availability of emergency equipment was shown to be crucial during the FDA and its availability could have arrested the accident progression early enough to minimize any radioactive release to the environment. As a result, licensees presented appropriate evaluations of the means to provide coolant make-up to the primary Heat Transport System (HTS), boilers, moderator, calandria vault, and irradiated fuel pools.

Evolution of radioactive dose rates in fresh sediment deposits along coastal rivers draining Fukushima contamination plume

OpenAIRE

Evrard, Olivier; Chartin, Caroline; Onda, Yuichi; Patin, Jeremy; Lepage, Hugo; Lef?vre, Ir?ne; Ayrault, Sophie; Ottl?, Catherine; Bont?, Philippe

2013-01-01

Measurement of radioactive dose rates in fine sediment that has recently deposited on channel bed-sand provides a solution to address the lack of continuous river monitoring in Fukushima Prefecture after Fukushima Dai-ichi nuclear power plant (FDNPP) accident. We show that coastal rivers of Eastern Fukushima Prefecture were rapidly supplied with sediment contaminated by radionuclides originating from inland mountain ranges, and that this contaminated material was partly exported by typhoons t...

Fukushima-derived radionuclides in the ocean and biota off Japan

OpenAIRE

Buesseler, Ken O.; Jayne, Steven R.; Fisher, Nicholas S.; Rypina, Irina I.; Baumann, Hannes; Baumann, Zofia; Breier, Crystaline F.; Douglass, Elizabeth M.; George, Jennifer; Macdonald, Alison M.; Miyamoto, Hiroomi; Nishikawa, Jun; Pike, Steven M.; Yoshida, Sashiko

2012-01-01

The Tōhoku earthquake and tsunami of March 11, 2011, resulted in unprecedented radioactivity releases from the Fukushima Dai-ichi nuclear power plants to the Northwest Pacific Ocean. Results are presented here from an international study of radionuclide contaminants in surface and subsurface waters, as well as in zooplankton and fish, off Japan in June 2011. A major finding is detection of Fukushima-derived 134Cs and 137Cs throughout waters 30–600 km offshore, with the highest activities asso...

The Project on the distribution of fallout radionuclide and their transfer through environment by Fukushima Daiichi NPP accident

Science.gov (United States)

Onda, Yuichi; Kato, Hiroaki; Yoshimura, Kazuya; Fukushima, Takehiko; Patin, Jeremy

2013-04-01

Radioactive contamination has been detected in Fukushima due to the nuclear accident at Fukushima Daiichi Nuclear Power Plant (NPP) following the earthquake and tsunami on 11 March 2011. Following comprehensive investigation (FMWSE project funded by MEXT, Japan; http://fmwse.suiri.tsukuba.ac.jp/) was conducted to confirm migration of radionuclides through natural environment including soils and rivers. Experimental catchments have been established in Yamakiya district, Kawamata Town, Fukushima prefecture, located about 35 km from Fukushima power plant, and designated as the evacuated zone. Approximate Cs-137 fallout in this area is 200 - 600 kBq/m2. (1) Migration study of radionuclides in natural environment including forests and rivers: 1) Depth distribution of radiocaesium in soils within forests, fields, and grassland, 2) Confirmation of radionuclide distribution and investigation on migration in forests, 3) Study on radionuclide migration due to soil erosion under different land use, 4) Measurement of radionuclides entrained from natural environment including forests and soils. (2) Migration study of radionuclides through hydrological cycle such as soil water, rivers, lakes and ponds, ground water: 1) Investigation on radionuclide migration through soil water, ground water, stream water, spring water under different land use, 2) Study on paddy-to-river transfer of radionuclides through suspended sediments, 3) Study on river-to-ocean transfer of radionuclides via suspended sediments, 4) Confirmation of radionuclide deposition in ponds and reservoirs. The main finding is as follows: 1) Migration of radionuclides to soil water, stream water and ground water was confirmed low at present. On the other hand, concentration of radiocaesium was found approximately 50 kBq/kg in the suspended sediments flowing down the river. 2) Amount of sediments deposited in the tank placed at the end of downstream within the USLE plot was confirmed together with the concentrations of

Fukushima : The Geo-Trauma of a Futural Wave

NARCIS (Netherlands)

Dolphijn, R.; Cole, David; Bradley, Joff

2016-01-01

The enduring effects of the March 2011 tsunami and nuclear meltdown at the Fukushima Dai-ichi Nuclear Power Station in Japan are explored in this paper through the notions of “geo-trauma” in the authors’ work and geophilosophy in Deleuze and Guattari’s philosophy. At the fulcrum of the 2011 global

Review of the international forum on peaceful use of nuclear energy and nuclear security. Taking the lessons learned from Fukushima Daiichi Nuclear Power Plant accident to the 2012 Seoul nuclear security summit

International Nuclear Information System (INIS)

Tazaki, Makiko; Suda, Kazunori; Suzuki, Mitsutoshi; Kuno, Yusuke; Mochiji, Toshiro

2012-06-01

The Japan Atomic Energy Agency (JAEA) held '2011 International Forum on the Peaceful Use of Nuclear Energy and Nuclear Security - Taking the lessons learned from Fukushima Daiichi Nuclear Power Plant Accident to the 2012 Seoul Nuclear Security Summit-' on 8 and 9 December, 2011. It intended to articulate effective strategies and measures for strengthening nuclear security using lessons learned from the Fukushima Nuclear Accident. Moreover, it was expected to explore comprehensive approaches which could contribute to enhancing both nuclear safety and security in order to support sustainable and appropriate development of the peaceful use of nuclear energy. This report includes abstracts of keynote speeches, summary of panel discussions and materials of the presentations in the forum. The editors take full responsibility for the wording and content of this report, excepts presentation materials. (author)

Review of the international forum on peaceful use of nuclear energy and nuclear security. Taking the lessons learned from Fukushima Daiichi Nuclear Power Plant accident to the 2012 Seoul nuclear security summit

Energy Technology Data Exchange (ETDEWEB)

Tazaki, Makiko; Suda, Kazunori; Suzuki, Mitsutoshi; Kuno, Yusuke; Mochiji, Toshiro [Japan Atomic Energy Agency, Department of Science and Technology for Nuclear Material Management, Tokai, Ibaraki (Japan)

2012-06-15

The Japan Atomic Energy Agency (JAEA) held '2011 International Forum on the Peaceful Use of Nuclear Energy and Nuclear Security - Taking the lessons learned from Fukushima Daiichi Nuclear Power Plant Accident to the 2012 Seoul Nuclear Security Summit-' on 8 and 9 December, 2011. It intended to articulate effective strategies and measures for strengthening nuclear security using lessons learned from the Fukushima Nuclear Accident. Moreover, it was expected to explore comprehensive approaches which could contribute to enhancing both nuclear safety and security in order to support sustainable and appropriate development of the peaceful use of nuclear energy. This report includes abstracts of keynote speeches, summary of panel discussions and materials of the presentations in the forum. The editors take full responsibility for the wording and content of this report, excepts presentation materials. (author)

Fukushima. From the earth quake to the nuclear disaster

International Nuclear Information System (INIS)

Coulmas, Florian; Stalpers, Judith

2011-01-01

The authors of the booklet who lived in Japan at the time of the earth quake and the following catastrophic nuclear accidents in Fukushima describe their experiences during the earth quake and the following days. Although Japan is used to natural disasters the tsunami and the consequences for the NPP Fukushima Daiichi surmounted any imagination. The challenges for the local authorities as a consequence of the catastrophic progress of the disaster, the suffering of the citizens and at the same time the discipline and serenity to the affected persons are reported.

Fukushima. Five years on - FAQs

International Nuclear Information System (INIS)

2016-03-01

On 11 March 2011, at 2:46 p.m. local time (6.46 a.m. CET), an earthquake measuring 9 on the Richter scale hit the east coast of Japan. The quake caused a tsunami, with waves as high as 38 metres, which led to large-scale flooding and destruction of roads, the power supply and other infrastructure along Japan's eastern seaboard. The earthquake and tsunami also struck several nuclear power plants. Fukushima Daiichi sustained the worst damage, triggering a chain of events which led to core meltdown, major hydrogen explosions and massive releases of radiation. Below, the Oeko-Institut answers the key questions about the disaster's timeline, latest assessments of the events, and the current situation in Fukushima.

The effect of the accident of Fukushima Daiichi Nuclear Power Plants on Niigata city based on tritium concentration in precipitation

Energy Technology Data Exchange (ETDEWEB)

Kataoka, N. [Department of Chemistry and Chemical Engineering, Faculty of Engineering, Niigata University 8050 Ikarashi 2-III ocho, Niigata-shi, Nishiku, Niigata Pref. 950-2181 (Japan); Environmental Analytical Center of Niigata Prefecture 53-1 Ojigouya, Kounan-ku, Niigata Pref. 950-1144 (Japan); Imaizumi, H.; Kano, N.; Ying, W. [Department of Chemistry and Chemical Engineering, Faculty of Engineering, Niigata University 8050 Ikarashi 2-III ocho, Niigata-shi, Nishiku, Niigata Pref. 950-2181 (Japan)

2014-07-01

The maximum value of tritium concentration in precipitation was 200 Bq/kg in Niigata city when atmospheric nuclear-bomb tests were performed in 1960s. After that, tritium concentration continuously decreased and reached to environmental revel (0.5~1.0 Bq/kg). However, after the accident of Fukushima daiichi nuclear power plants, the tritium concentration in precipitation increased in Niigata city. Therefore the observation of tritium concentration had to be carried out. In our laboratory, we have investigated the tritium concentration in precipitation and also investigated the relation between the tritium concentration and other ion (Na⁺, Mg⁺, K⁺, Ca⁺, Cl⁻, NO3⁺ or SO₄²⁻) concentration in precipitation in Niigata city. In this study, precipitation in Niigata city was gathered monthly and the evaluation of tritium concentration in precipitation was performed. In addition, we also collected the precipitation hourly (short precipitation). Each water sample thus obtained was distilled with sodium peroxide and potassium permanganate. Then the water sample thus distilled was enriched in SPE electronic enrichment apparatus, and the tritium concentration in the sample thus treated was measured in a liquid scintillation counter. On the other hand, each ion concentration in the sample was measured by ion chromatography or Atomic Absorption Spectrometry. From the above the mentioned, the following five matters can be found. (1) The tritium concentration in the samples in March and April 2011 were twice or three times higher than that in March and April in annual years. In other words, it is considered that the thus high level concentration of tritium leads to the evaluation of the effect of the accident of the Fukushima nuclear power plants on Niigata city. (2) As to the sample, the concentration of the non-sea salt Ca²⁺ (nssCa²⁺) is similar to that in March and April in annual years. (3) For each short precipitation sample collected on March 15, 2011

Impact of the Fukushima Daiichi nuclear power plant accident on local community and healthcare services

International Nuclear Information System (INIS)

Oikawa, Tomoyoshi

2013-01-01

The Soso region of Japan, located in the northern part of the Pacific side of Fukushima Prefecture, has suffered tremendously from widespread damage caused by the earthquake, tsunami and the Fukushima Dai-ichi nuclear power plant accident. Immediately after the disaster it even seemed that the restoration of this region itself would not be possible. However after six months, the Indoor Restriction Order and evacuation orders within a 20 to 30 km zone from the plant, such as the Evacuation-Prepared Area in Case of Emergency, were lifted and all of those restrictions for the planned evaluation zone has been eased in line with the actual conditions of each region. A year and a month after the earthquake, the Caution Zone, which was declared to prohibit the entry to the zone within the 20 km radius from the plant, was lifted. Thus people can now enter as close as 10 km from the plant. Minami-Soma city is an administrative district which had the largest population (approximately 71,500 residents) within the 20 to 30 km zone prior to the earthquake. It was, also, the only district where the evacuation was not conducted by the municipality. The city is now called the Genpatsu frontline district as it is the closest city to the plant where people have continued to live. Due to the damage caused by the earthquake and Tsunami, the city has suffered both from destruction by the tsunami and radiation, and people are still facing numerous problems despite the fact that the city appears to have been restored on its surface. It is very unfortunate that much of the medical data from the region was lost in the confusion after the Great East Japan Earthquake. In this paper various facts after the disaster based on the data left in the So-so region, Minamisoma city, and Minamisoma municipal general hospital are reported. (author)

Soil sampling and analytical strategies for mapping fallout in nuclear emergencies based on the Fukushima Dai-ichi Nuclear Power Plant accident

International Nuclear Information System (INIS)

Onda, Yuichi; Kato, Hiroaki; Hoshi, Masaharu; Takahashi, Yoshio; Nguyen, Minh-Long

2015-01-01

The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident resulted in extensive radioactive contamination of the environment via deposited radionuclides such as radiocesium and 131 I. Evaluating the extent and level of environmental contamination is critical to protecting citizens in affected areas and to planning decontamination efforts. However, a standardized soil sampling protocol is needed in such emergencies to facilitate the collection of large, tractable samples for measuring gamma-emitting radionuclides. In this study, we developed an emergency soil sampling protocol based on preliminary sampling from the FDNPP accident-affected area. We also present the results of a preliminary experiment aimed to evaluate the influence of various procedures (e.g., mixing, number of samples) on measured radioactivity. Results show that sample mixing strongly affects measured radioactivity in soil samples. Furthermore, for homogenization, shaking the plastic sample container at least 150 times or disaggregating soil by hand-rolling in a disposable plastic bag is required. Finally, we determined that five soil samples within a 3 m × 3-m area are the minimum number required for reducing measurement uncertainty in the emergency soil sampling protocol proposed here. - Highlights: • Emergency soil sampling protocol was proposed for nuclear hazards. • Various sampling procedures were tested and evaluated in Fukushima area. • Soil sample mixing procedure was of key importance for measured radioactivity. • Minimum number of sampling was determined for reducing measurement uncertainty

Five years after Fukushima, it's time to seize new nuclear opportunities

Energy Technology Data Exchange (ETDEWEB)

Shephers, John [nuclear24, Redditch (United Kingdom)

2016-05-15

In March of this year, we marked a painful chapter in the history of the world's civil nuclear energy industry as we reflected on the earthquake and tsunami that struck Japan five years ago - leading to the nuclear accident at Fukushima-Daiichi. In moving on, the nuclear industry needs to absorb the lessons learned from Fukushima and there are now clear signals for going on with nuclear.