Fukushima Nuclear Power Plant Research Articles

Basic Performance Evaluation of a Radiation Survey Meter That Uses a Plastic-Scintillation Sensor.

After the Fukushima nuclear power plant accident in 2011, many types of survey meters were used, including Geiger-Müller (GM) survey meters, which have long been used to measure β-rays. Recently, however, a novel radiation survey meter that uses a plastic-scintillation sensor has been developed. Although manufacturers' catalog data are available for these survey meters, there have been no user reports on performance. In addition, the performance of commercial plastic-scintillation survey meters has not been evaluated. In this study, we experimentally compared the performance of a plastic-scintillation survey meter with that of a GM survey meter. The results show that the two instruments performed very similarly in most respects. The GM survey meter exhibited count losses when the radiation count rate was high, whereas the plastic-scintillation survey meter remained accurate under such circumstances, with almost no count loss at high radiation rates. For measurements at background rates (i.e., low counting rates), the counting rates of the plastic-scintillation and GM survey meters were similar. Therefore, an advantage of plastic-scintillation survey meters is that they are less affected by count loss than GM survey meters. We conclude that the plastic-scintillation survey meter is a useful β-ray measuring/monitoring instrument.

ОБОСНОВАНИЕ НОВОЙ ПРИЧИННО-СЛЕДСТВЕННОЙ ТРАКТОВКИ РАЗВИТИЯ И ТРАНСФОРМАЦИИ ЧРЕЗВЫЧАЙНЫХ СИТУАЦИЙ НА ПРИМЕРЕ АВАРИИ НА АТОМНОЙ ЭЛЕКТРОСТАНЦИИ «ФУКУСИМА-1»

Using the example of the radiation accident at the Fukushima-1 nuclear power plant and subsequent measures to discharge tritium-containing aqueous coolant into the ocean, the adequacy of a new causal interpretation – the «triangle of emergencies», justifying and explaining scenarios of mutual transition of one type of emergency into another, as well as its graphical interpretation is considered. The issues of existing and possible consequences related both directly to the accident and to the discharge of the coolant are investigated. The results of calculating the change in the radioactivity of tritium in the volume of water planned for discharge for a period equal to ten of its half-life are presented. The prospects of applying the concept of an «emergency triangle» are considered, which are seen in the construction of an «emergency space», which is an array of emergency data collected for the purpose of analyzing, interpreting information, establishing cause-effect relationships and forecasting, as well as the principles of its formation.

Ultrastructural Analysis of Large Japanese Field Mouse (Apodemus speciosus) Testes Exposed to Low-Dose-Rate (LDR) Radiation after the Fukushima Nuclear Power Plant Accident.

Since the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, great attention has been paid to the impact of chronic low-dose-rate (LDR) radiation exposure on biological systems. The reproductive system is sensitive to radiation, with implications connected to infertility. We investigated the testis ultrastructure of the wild large Japanese field mouse (Apodemus speciosus) from three areas contaminated after the FDNPP accident, with different levels of LDR radiation (0.29 µSv/h, 5.11 µSv/h, and 11.80 µSv/h). Results showed good preservation of the seminiferous tubules, comparable to the unexposed animals (controls), except for some ultrastructural modifications. Increases in the numerical density of lipid droplet clusters in spermatogenic cells were found at high levels of LDR radiation, indicating an antioxidant activity rising due to radiation recovery. In all groups, wide intercellular spaces were found between spermatogenic cells, and cytoplasmic vacuolization increased at intermediate and high levels and vacuolated mitochondria at the high-level. However, these findings were also related to the physiological dynamics of spermatogenesis. In conclusion, the testes of A. speciosus exposed to LDR radiation associated with the FDNPP accident showed a normal spermatogenesis, with some ultrastructural changes. These outcomes may add information on the reproductive potential of mammals chronically exposed to LDR radiation.

Safety evaluation of Multiple Steam Generator Tube rupture accident using the best estimate plus uncertainty approach

Following the disaster in Fukushima Nuclear Power Plant (NPP) in 2011, the awareness of securing the safety of NPP under extreme events has been raised. For this purpose, the concept of Design Extension Conditions (DECs) was introduced, to enhance the plant’s capability to withstand events that are more severe than Design Basis Accidents (DBA), such as Multiple Steam Generator Tube Rupture (MSGTR) accident, given its rapid progression and significant potential for large release of radioactive materials to the environment. It is worth noting that MSGTR has never occurred during the commercial operation of nuclear power plant, therefore the knowledge of consequences of the event and potential mitigation strategy is limited. In this study, a postulated MSGTR (simultaneous rupture of 5 U-tubes in a single SG) accident is analysed using the best-estimate thermal hydraulics code RELAP5/SCDAPSIM/MOD3.4. The main focus of this work is evaluation of appropriate operator mitigation actions under various inherent uncertainties. To this end, the best estimate plus uncertainty (BEPU) approach is adopted, whereby RELAP5/SCDAPSIM/MOD3.4 was coupled to the statistical analysis software, DAKOTA, to conduct the uncertainty quantification (UQ). Using BEPU analysis, an ensemble of system responses under various epistemic and aleatory uncertainties is obtained and used to validate the efficacy of operator actions in bringing the plant to a safe shutdown condition.

International Wrongfulness of Japan's NCW Sea Discharge

International Wrongfulness of Japan's NCW Sea Discharge

BIBLIOMETRIC ANALYSIS OF THE GREATEST NUCLEAR DISASTERS: WHAT IS KNOWN SO FAR AND WHAT ARE THE PROSPECTS?

Abstract. The high potential of nuclear power to combat climate change and support sustainable development plays a critical role in achieving the goal of the Paris Agreement. Moreover, with the ever-increasing demand for electricity, it is essential to consider nuclear power as a reliable source of energy. However, it should be noted that although the risk of a radiological accident is small, it always exists, and therefore it is crucial to have a complete understanding of the management of nuclear power. Herein, we present a statistical review of nuclear accident research at Chernobyl and Fukushima Nuclear Power Plants using bibliometric analysis to identify key patterns in scientific results and current issues in accident research. More than 10,000 articles have been collected from the SCOPUS database covering the periods 1986–2022 and 2011–2022 on Chernobyl and Fukushima, respectively. The results were obtained from two perspectives: first, we identified stages through which pre- and post-accident researches have evolved, and then we analysed the spatial correlation between energy-economic performance and scientific literature for the leading productive countries. From the analysis of research trends, it was found that the number of articles increased sharply immediately after the accident and slightly decreased over time. Among the most attractive subject categories in terms of the largest number of publications and received citations were environmental sciences, medicine and energy policy. The productive country ranking was mostly topped by the country in which the accident occurred. Spatial statistical analysis revealed a strong correlation between the scientific productivity and energy-economic performance of the leading countries.

Developing a broad perspective of future work and career in medical students through field trips to a disaster area: a qualitative study

ObjectiveField trips to disaster-affected areas (FTDAs) without a specific purpose, such as medical cooperation, are widely used in medical education. However, what medical students gain from FTDAs remains unclear. The present study aimed to clarify what medical students gain from FTDAs. Five medical students who had visited the Fukushima nuclear power plant in Japan participated in a semi-structured group interview to ask what they gained from such a visit. The narratives were analysed using open coding.ResultsThe following four themes emerged: “Spirit of scientific inquiry”, “Foundation for lifelong education and personal growth”, “Broadened understanding of the medical profession”, and “Importance of practicing medicine in the community setting”. The ambiguity of medical students’ specific roles in the field trip compared to the fieldwork may have encouraged them to make sense of the experience from their perspective. As a result, students may have gained a broader perspective of their future work and career through the FTDA. If medical educators can gain consensus from the residents of a disaster site, different disaster-affected areas can be potential sites for medical education using FTDAs.

Establishing a mechanism for international cooperation for Fukushima nuclear-contaminated water monitoring

The Japanese government’s unilateral decision to discharge the nuclear-contaminated water from the Fukushima nuclear power plant into the ocean has caused immense nuclear safety risks. Monitoring the unclear-contaminated water is a starting point to combat these risks and seek remedies for the rights and interests of all concerned parties. The establishment of a mechanism for international cooperation in this respect is necessary to handle the risks of the Fukushima nuclear-contaminated water and to lay the foundation of a framework for tackling any future disposal of nuclear-contaminated water following Japan’s example. At present, the international legal systems in the spheres of nuclear safety and security, marine environmental protection, and other areas, as well as the questioning of the monitoring reports of the International Atomic Energy Agency (IAEA) by the relevant parties, the monitoring practices of historical nuclear accidents, and numerous radioactivity monitoring mechanisms have provided the institutional and practical basis for constructing such a mechanism. The mechanism can be promoted by the IAEA through its existing mechanisms or be jointly initiated by China, the Russian Federation, the Republic of Korea, the Democratic People’s Republic of Korea, and the Pacific Island countries, among other stakeholders. Specifically, this mechanism should consist of three levels: first, the framework of the basic legal system, including the cooperative principles of national sovereignty, interest-relatedness, and procedural fairness, and the signing of the Framework Convention on the Monitoring of Fukushima’s nuclear-contaminated water and its Optional Protocol; second, the organizational structure and its responsibilities, which may include the Conference of Parties as the decision-making body, the Secretariat as the central coordinating body, and the monitoring committees in various fields as specific implementing agencies; and third, specific administrative arrangements, which involve the standardization of monitoring, the management system of monitoring networks and stations, the rules for monitoring procedures, and the rules for the utilization of the monitoring data, etc. With the urgent need for the scientific and fair monitoring of Fukushima’s nuclear-contaminated water, China, as a stakeholder country, can promote the establishment of such a mechanism for monitoring nuclear-contaminated water through the following paths: ① It is necessary to clarify the factors affecting the construction of an international cooperation mechanism for monitoring nuclear-contaminated water so as to ascertain the standpoints of the stakeholders, claims of their interests, contents of their cooperation, and the relevant international relations. ② On the basis of existing practices, China should consider improving the monitoring mechanism to cope with the risks of the discharge of Fukushima’s nuclear-contaminated water by formulating targeted policies and systems, setting up specialized monitoring institutions, and establishing a systematic monitoring network system. ③ This is an effective way for China to actively promote the participation of stakeholders in the construction of an international cooperation mechanism for monitoring nuclear-contaminated water in Fukushima by further innovating the dissemination mechanism to address the risk of Fukushima’s nuclear-contaminated water discharging into the sea and facilitating the identification of issues for international cooperation in monitoring Fukushima’s nuclear-contaminated water based on the concept of a community with a shared future for mankind.

International law obligations for the disposal of Fukushima nuclear-contaminated water under the principles of nuclear safety

The disposal of contaminated water from Japan’s Fukushima nuclear power plant is a significant international nuclear safety issue with considerable cross-border implications. This matter requires compliance not only with the law of the sea but also with the principles of nuclear safety under international law. These principles serve as the overarching tenet of international and China’s domestic nuclear laws, applicable to nuclear facilities and activities. The principle of safety in nuclear activities is fully recognized in international and domestic laws, carrying broad legal binding force. Japan’s discharge of nuclear-contaminated water into the sea violates its obligations under the principle of safety in nuclear activities, including commitments to optimum protection, as low as reasonably practicable, and prevention. The Japanese government and the International Atomic Energy Agency (IAEA) have breached the obligation of optimum protection by restricting the scope of assessments, substituting core concepts, and shielding dissenting views. In the absence of clear radiation standards, they have acted unilaterally without fulfilling the obligation as low as reasonably practicable principle. The discharge of Fukushima nuclear-contaminated water poses an imminent and unpredictable risk to all countries worldwide, including Japanese residents. Japan and the IAEA should fulfill their obligations under international law regarding disposal, adhering to the principles of nuclear safety, including optimum protection, the obligation as low as reasonably practicable, and prevention through multilateral cooperation. Specifically, the obligation to provide optimum protection should be implemented by re-evaluating the most reliable disposal technologies and methods currently available and comprehensively assessing various options. The standard of the obligation as low as reasonably practicable requires that the minimization of negative impacts on human health, livelihoods, and the environment should not be subordinated to considerations of cutting costs and expenses. Multilateral cooperation should be promoted through the establishment of sound multilateral long-term monitoring mechanisms for the discharge of nuclear-contaminated water, notification and consultation obligations, and periodic assessments. These obligations under international law were fulfilled after the accidents at the Three Mile Island and Chernobyl nuclear power plants. The implications of the principles of nuclear safety align with the concept of building a community of shared future for nuclear safety advocated by China. In cases of violations of international law regarding the disposal of nuclear-contaminated water that jeopardize the concept of a community of a shared future for nuclear safety, China can also rely on its own strength to promote the implementation of due obligations through self-help.

지리 교과에서 안전교육 내용 구성을 위한 방사능에 대한 위험 인식 분석

Objectives This study aims to provide basic data for the construction of safety education contents in geography subject by examining university students' risk perception of radioactivity with an optimism bias through a real case of the Fukushima nuclear power plant accident in Japan.
 Methods To this end, a questionnaire composed of questions asking about risk perception of radioactivity and optimism bias in risk perception of radioactivity was distributed and collected to 134 university students in Seoul, South Korea. A one-way ANOVA was conducted to see the difference in risk perception of radioactivity according to the type of visit to Japan (visit to Tokyo, non-visit to Japan, visit to Japan). In addition, factor analysis and multiple regression analysis were performed to identify the optimism bias in the risk perception of radioactivity, and then the difference in optimism bias according to the type of visit to Japan was analyzed through MANOVA (Multivariate Analysis of Variance).
 Results The terms of risk perception of radioactivity, the degree of perception that Tokyo is safe from radiation was significantly higher in the Tokyo visiting group than in the other two groups. As a result of factor analysis to identify optimism bias, three factors (optimistic perception, avoidance perception, and wait-and-see perception) were derived, and as a result of multiple regression analysis, it was found that optimistic perception and avoidance perception had a positive effect on optimism bias in order. As a result of MANOVA, the Tokyo visiting group showed significantly higher perceptions of both optimistic and avoidance compared to the other two groups.
 Conclusions Optimism bias and its sub-factors, optimistic perception and avoidance perception, were identified in the risk perception of radioactivity. Because optimism bias makes it difficult to make logical judgments and rational decision-making in risk situations, meta-cognition for optimism bias in relation to risk perception should be considered when constructing safety education contents in geography subject.

Longitudinal effects of disaster-related experiences on problem drinking among Fukushima nuclear plant workers.

In the Fukushima nuclear power plant disaster of March 11, 2011, plant workers were exposed to various traumatic events and reported a subsequent increase in alcohol use. To determine the relationship between disaster-related experiences and problem drinking, we conducted a three-year follow-up study. Problem drinking among the nuclear plant workers was assessed annually from 2012-2014 using a modified version of the CAGE questionnaire that asked about current, rather than lifetime, drinking. A total of 1378 workers provided at least one CAGE response, and 2875 observations were used in the present analysis. Mixed-effects logistic regression models were used to analyze the relationship between disaster-related experiences and problem drinking over time. The prevalence of problem drinking (CAGE score ≥2) increased over time. At the baseline assessment in 2012, a year after the disaster, plant workers who had experienced life-threatening danger and discrimination had significantly more symptoms of problem drinking, which persisted over the following 2 years. Although at baseline, plant workers who had experienced major property loss or the death of a colleague showed no significant differences in problem drinking symptoms from those without such experiences, over the next 2 years their problem drinking increased significantly. Individuals who experienced life-threatening danger and discrimination during the Fukushima nuclear power plant disaster reported an increase in problem drinking. Although major property loss and the death of a colleague did not elevate problem drinking prevalence at baseline, it did so over the next 2 years. Different adverse effects of a natural disaster appear to differentially increase drinking behavior over time.

Multi-pixel photon counter-based gamma camera with pinhole collimator to locate Cs-137 sources at high dose rates for the Fukushima nuclear power plant

The Fukushima Daiichi Nuclear Power Plant was severely damaged during the 2011 Great East Japan Earthquake. However, the ongoing decommissioning work has been limited by the complexity of the reactor's internal structure and very high radiation levels; locating radioactive sources is essential for efficient decommissioning. Conventional gamma cameras are mainly designed for low radiation dose (∼mSv/h) and using them under high radiation conditions is difficult (>Sv/h). Therefore, we developed a pinhole gamma camera with a gamma radiation detector consisting of a high-speed YGAG scintillator array and multi-pixel photon counters to locate radioactive sources at high dose rates. The gamma-ray photon signals captured by the developed two-dimensional detector array can be processed at a speed as high as >1 MHz/pixel using the developed large scale integrated circuit. Herein, we report the measurement results of an extremely high radioactivity of 137Cs (∼34 TBq) using the developed gamma camera. The gamma-ray source position was determined using an angular size of ∼4.6°, with images obtained at 2 m from the radioactive source and at a dose rate of 0.3 Sv/h. The direct gamma rays with a photoelectric peak at 662 keV and scattered component of gamma rays can be distinguished from the measured spectrum. We also characterize the imaging capability of the 137Cs depending on the detected gamma-ray energies and discuss related details.

Prolonged impact of the Fukushima Nuclear Power Plant Accident on health and society

Prolonged impact of the Fukushima Nuclear Power Plant Accident on health and society Naomi Ito, Research Assistant at the Fukushima Medical University, tells us how the 2011 Fukushima Daiichi Nuclear Power Plant Accident impacted and continues to impact local residents. The health effects on local residents following a nuclear power plant accident are diverse, not only because of radiation exposure but also because of changes in lifestyle and social environment. It has also been indicated that various environmental changes that could emerge during the restoration process may affect residents in various ways over a long time. On March 11, 2011, the Great East Japan Earthquake struck Japan with a magnitude of 9.0. Within an hour, a tsunami hit the shore. Three reactors at the Fukushima Daiichi Nuclear Power Plant (FDNPP, operated by Tokyo Electric Power Company) lost power. The reactors could not be cooled, and core meltdowns occurred, which resulted in an explosion due to hydrogen being generated at high temperatures. As a result, radioactive materials were released and scattered northwest from the power plant.

The Influence of Japanese Nuclear Sewage Pollution on China's Import and Export Trade

The Fukushima Daiichi disaster occurred in 2011, leading to ongoing concerns about contaminated water. China and Japan have a complex trade relationship, which makes any disruption important. This background sets the stage for exploring potential trade implications. The research will discuss how Japan's nuclear and water pollution affect China's import and export trade. First, we will cover the background of the accident at the Fukushima nuclear power plant in Japan and the atomic sewage treatment plan. Next, we will analyze the potential impact of this incident on China's import and export trade, covering trade relations, seafood, and other aspects. Finally, we will discuss China's measures and proposals to address this impact. In short, it is concluded that Sino-Japanese trade will be subject to inevitable fluctuations in the short and medium term, but in the long run, its transaction will still show a steady upward trend.

RADIOECOLOGY: PAST, PRESENT, FUTURE

The article deals with issues related to the development of radioecology as an independent scientific discipline. The achievements of the past years, the studies that are currently being carried out, as well as promising areas of development in this area are analyzed. A corrected periodization of the stages of development of radioecology is proposed, taking into account the experience accumulated to date in the field of this discipline. At the initial stage (1895-1929:), empirical material was collected; at the first stage (1930-1960), the theoretical foundation was laid and radioecology was formed as an independent discipline; at the second stage (1961-1990), intensive development of radioecology was noted, and at the third stage (1991-2010) - progressive development of radioecology; the forth modern stage of radioecology development falls at the beginning of the twentieth century (2011 - present). For each stage the main scientific achievements and evolution of ideas in the field of radioecology are considered. It is postulated that at present the development of this discipline is associated with the further improvement of world nuclear technologies, the elimination of the consequences of a number of radiation incidents (the accident at the Fukushima nuclear power plant, 2011), the revision of the concept of radiation protection of the environment and a number of other provisions. Particular attention is paid to forest radioecology, one of the most important main directions of this science.

Charmed by Johann Georg Pinsel

The article describes the special interest that representatives of Japanese intelligentsia took in the personality and professional work of the outstanding Ukrainian art critic and museum curator Borys Voznytskyi. During the times of the Soviet regime, in the conditions of ideological oppression and the destruction of spiritual heritage in Ukraine (religious art, in particular), Borys Voznytskyi preserved artistic rarities of Ukraine (Halychyna), particularly the works of Johann Georg Pinsel. The article traces the creative contact of the cultural scholar Fue Katayama with the Lviv maestro and her initiative to publish in Japan an illustrated album of Pinsel’s works. The publication took place in a tragic year for Japan, in the aftermath of the disaster at the Fukushima-1 nuclear power plant. The publication of the album is shown as a manifestation of the concept of “on” — a spiritual obligation, taken on by Fue Katayama.

Five years after the Earthquake and nuclear accident: Loss and its psychological effect

Abstract Background On March 11, 2011, the Great East Japan Earthquake hit Tohoku. The Fukushima nuclear power plant accident forced many people to relocate, leaving their hometowns. This study focused on the sense of loss and its psychological effect on the people of Fukushima five years after the earthquake and nuclear accident. Methods Quantitative and qualitative analysis from a questionnaire survey including the IES-R scale and open-ended questions. Results 1021 people participated in this study. At the time of the survey, 490 people relocated within Fukushima prefecture and 531 people left. During the nuclear accident, 632 participants were close to the nuclear power plant; 407 participants reported actual nuclear accident experiences such as exposure to blast ashes, seeing the explosion, hearing explosive sounds and escaping. People lost family members (n = 112) and homes (n = 338) due to the tsunami and earthquake; 439 lost jobs after the earthquake and 410 had economic difficulties; 736 reported their sadness over losing hometowns; 391 people showed IES-R scores over 25, suggesting potential PTSD (Post Traumatic Syndrome). From a multivariate analysis, psychological distress was significantly affected by nuclear accident experience (OR = 1.43, p = 0.04), lost jobs (n = 1.57, p = 0.01), economic difficulty (OR = 1.68, p < 0.01), hometown loss (OR = 1.58, p < 0.05), feeling difficulty living (OR = 3.84, p < 0.01) and social isolation (OR = 1.74, p < 0.01). For hometown loss, significant factors were lost houses (n = 596, p < 0.01), friends (n = 590, p < 0.05), life (n = 421, p < 0.01), family relationships (n = 377, p < 0.01), community (n = 403, p < 0.01) and futures (n = 310, p < 0.01). From qualitative analysis,”I relocated with the children, leaving behind my husband which I regret (a mother with children)” and others. Discussion and conclusions After natural disasters, nuclear accidents and wars, people suddenly lose their special monitoring and support are necessary for affected people. Key messages • Many people still suffer from PTSD after the Nuclear Power Plant accident after 5 years. • Many people suffer from a variety of loss such as loss of hometown, friends, family and others due to migration from Fukushima.

Tritium-Containing nuclear waste water discharge from Fukushima’s risks and concerns

The focus of this paper is on the problems posed by tritium in the nuclear wastewater from the Fukushima nuclear power plant. The Japanese government has decided to discharge wastewater containing tritium into Pacific Ocean. However, there are still differing opinions on the effects of tritium, and it is not possible to prove that large amounts of tritium have no effect. So the research of tritium-containing wastewater is necessary. This paper reviews and discusses what is known about the tritium-containing wastewater from Fukushima and the potential impacts of tritium. This paper argues that because of the potential effects of tritium and the fact that tritium-containing wastewater discharged into the sea will eventually spread around the world, more impact assessments of tritium, scientific management of nuclear wastewater discharged from Fukushima, and follow-up investigations should be conducted.

Against an insufficient intervention for patients with alcoholism or PTSD: An activity report on a psychiatric clinic after the 2011 complex disaster in Fukushima, Japan

Despite numerous studies using questionnaires to assess mental health problems among disaster victims following a disaster, only a few have examined actual medical treatment situations. Surveys of residents in disaster-affected areas following the Great East Japan Earthquake and Fukushima nuclear power plant disaster also indicate deteriorated mental health among survivors; however, concrete evidence of increased individuals seeking treatment at psychiatric institutions is still scarce.Using medical records of a psychiatric clinic in an affected area during the chronic phase after a disaster, this study investigated the status of interventions for patients with alcoholism, post-traumatic stress disorder (PTSD), and others, including whether violence occurred during treatment.We found that 730 patients visited the clinic for a year, but a few with alcoholism received treatment. Patients who experienced traumatic stress during the disaster had a higher treatment discontinuation rate, though it is not correlated with their involvement in violence. However, a diagnosis of complex PTSD was correlated with involvement in violence during the treatment.The psychiatric clinic providing care during the chronic phase of the post-disaster period did not provide sufficient treatment for alcoholism, where therapeutic interpersonal interaction is emphasized, or for PTSD, where trauma-focused psychotherapy is the standard of care. It is difficult to ensure the availability of highly specialized resources and the establishment of comprehensive ties with the local people in affected areas, however, such a situation poses a challenge.

No increase in translocated chromosomal aberrations, an indicator of ionizing radiation exposure, in childhood thyroid cancer in Fukushima Prefecture

To investigate the effects of radiation exposure due to the Fukushima nuclear power plant accident, following the disaster Fukushima Prefecture launched thyroid ultrasound examinations of residents who were generally younger than 18 years at the time of the earthquake. As the rate of pediatric thyroid cancer was higher than expected, we conducted biological dose assessment based on the frequency of translocated chromosome (Tr) aberrations using peripheral blood lymphocytes. Tr formation frequency was compared among the thyroid cancer (n = 38, median age 18 years, age range 12–26 years), thyroid-related disease (n = 30, median age 21 years, age range 15–28 years), and healthy controls (n = 31, median age 22 years, age range 20–23 years) groups. Tr aberration frequency was initially significantly higher in the thyroid cancer than in the other two groups; however, differences among the groups disappeared after adjusting for history of CT scan, as 92%, 67%, and 28% of those in the thyroid cancer, thyroid-related disease, and control groups, respectively, had undergone CT previously. Therefore, the significant difference in the initial number of Tr formations is presumably due to radiation exposure from CT. Accordingly, the effects of medical exposure on the chromosomes of children and adolescents should be noted.