Nuclear Power Plant Accident Research Articles

Bleaching and drifting

This article describes the possibilities of art workshops which have been conducted in Fukushima Prefecture that were affected by the earthquake, tsunami, and nuclear power plant accident on March 11, 2011. In coastal areas, many people experienced unexpected domestic migrations/relocations and unwelcome changes in their lives due to the disaster, moving multiple times and living in a state akin to drifting. In these workshops, participants recalled their history and context, created artwork as their navigational chart of life while rebraiding individual narratives with images, memories, and recollections that associated with objects as a part of hyperobjects of tsunami and nuclear disasters. For their complicated situation after the disaster, the workshops provided the opportunities to negotiate with objects as non-human things which have a longer lifespan than humans. It became the activities supporting peoples who lost the continuity of their lives with their hometown. These recovery and support programs through art workshops will be an ecosophic approach based on non-discursive, aesthetic, and ethic means to change the human-centric dominant paradigm.

Impact of Nuclear Pollution on the Population and Diversity of Plankton

Plankton, as a crucial component of aquatic ecosystems, plays a key role in maintaining ecological balance with its population and diversity. However, with the increase in human activities, the emission of nuclear waste, and the frequency of nuclear accidents, the issue of nuclear pollution has become increasingly severe, posing a significant threat to the living environment of plankton. The primary sources of nuclear pollution are the discharge of nuclear waste and leaks from nuclear power plant accidents. These radioactive substances dissolve in water and emit radiation, causing severe damage to the aquatic ecosystem. Plankton, such as algae and protozoa, due to their characteristics, are more susceptible to radiation. The impact of nuclear pollution on the population and diversity of plankton is evident. To protect the balance of aquatic ecosystems, it's necessary to strengthen the management and regulation of nuclear pollution, reduce the discharge of nuclear waste, and lower the risk of nuclear accidents. Also, for water bodies already affected by nuclear pollution, effective purification measures should be taken to restore the health of the aquatic ecosystem.

A study on well-being of residents in the affected areas by nuclear power plant accident

A study on well-being of residents in the affected areas by nuclear power plant accident

Resilient design in nuclear energy: Critical lessons from a cross-disciplinary analysis of the Fukushima Dai-ichi nuclear accident

This paper presents a multidisciplinary analysis of the Fukushima Dai-ichi Nuclear Power Plant accident. Along with the latest observations and simulation studies, we synthesize the time-series and event progressions during the accident across multiple disciplines, including in-plant physics and engineering systems, operators' actions, emergency responses, meteorology, radionuclide release and transport, land contamination, and health impacts. We identify three key factors that exacerbated the consequences of the accident: (1) the failure of Unit 2 containment venting, (2) the insufficient integration of radiation measurements and meteorology data in the evacuation strategy, and (3) the limited risk assessment and emergency preparedness. We conclude with new research and development directions to improve the resilience of nuclear energy systems and communities, including (1) meteorology-informed proactive venting, (2) machine learning-enabled adaptive evacuation zones, and (3) comprehensive risk-informed emergency planning while leveraging the experience from responses to other disasters.

Surface and subsurface dispersal of radioactive materials from Fukushima by subpolar gyre and intermediate waters in the North Pacific

Radioactive materials were released into the ocean following the Fukushima Daiichi Nuclear Power Plant accident in 2011. Six years after the accident, the radioactive material concentration was markedly increased in the Okhotsk Intermediate Water (OIW) of the Sea of Okhotsk. This material may have been subjected to southward subsurface dispersal by the North Pacific Intermediate Water (NPIW), which originates from the OIW. The spatiotemporal limitations of available methods have made it challenging to track the dispersal paths of radioactive materials in the North Pacific Subpolar region. Here, we performed a tracer experiment using a three-dimensional numerical model to determine the path of 137Cs from Fukushima to the Sea of Okhotsk via surface subpolar gyre currents and subsurface dispersion by OIW and NPIW. The results showed that the 137Cs concentration in the Sea of Okhotsk increased via the surface current and moved progressively southward via OIW six years after the accident and eastward via OIW and NPIW nine years after the accident, indicating that 137Cs transported by NPIW entered the subtropical region. Based on experiments, this temporal change was mainly caused by ocean currents. Thus, subsurface recirculation of radioactive material via the OIW and NPIW should be considered based on the predicted path and travel time of additional materials released from the power plant.

Predicting the core thermal hydraulic parameters with a gated recurrent unit model based on the soft attention mechanism

Accurately predicting the thermal hydraulic parameters of a transient reactor core under different working conditions is the first step toward reactor safety. Mass flow rate and temperature are important parameters of core thermal hydraulics, which have often been modeled as time series prediction problems. This study aims to achieve accurate and continuous prediction of core thermal hydraulic parameters under instantaneous conditions, as well as test the feasibility of a newly constructed gated recurrent unit (GRU) model based on the soft attention mechanism for core parameter predictions. Herein, the China Experimental Fast Reactor (CEFR) is used as the research object, and CEFR 1/2 core was taken as subject to carry out continuous predictive analysis of thermal parameters under transient conditions., while the subchannel analysis code named SUBCHANFLOW is used to generate the time series of core thermal-hydraulic parameters. The GRU model is used to predict the mass flow and temperature time series of the core. The results show that compared to the adaptive radial basis function neural network, the GRU network model produces better prediction results. The average relative error for temperature is less than 0.5 % when the step size is 3, and the prediction effect is better within 15 s. The average relative error of mass flow rate is less than 5 % when the step size is 10, and the prediction effect is better in the subsequent 12 s. The GRU model not only shows a higher prediction accuracy, but also captures the trends of the dynamic time series, which is useful for maintaining reactor safety and preventing nuclear power plant accidents. Furthermore, it can provide long-term continuous predictions under transient reactor conditions, which is useful for engineering applications and improving reactor safety.

Dynamics of radioactive contamination of lingonberry (Vaccinium vitis-idaea L.) in the forests of Zhytomyr Polissia (Ukraine) since the Chernobyl Nuclear Accident

The article presents results of study of levels of radioactive soil contamination and 137Cs activity concentration in the aboveground part of lingonberry (Vaccinium vitis-idaea L.) phytomass and berries on permanent experimental plots in different years since the Chernobyl Nuclear Power Plant accident (forest site type conditions — moist fairly infertile pine site type (B3), soils — soddy-podzolic sandy-loam on fluvioglacial sands). The research was conducted at the Poliskyi Branch of the Ukrainian Research Institute of Forestry and Forest Melioration named after G.M. Vysotsky over the years 1998–2021, utilized methods generally accepted in forest science and radioecology were used. Results were processed using statistical analysis. To substantiate the research, an official reporting data from forestry enterprises of the Volyn, Rivne and Zhytomyr regions were used. An analytical review of the state of research on this problem revealed that at the last 10–15 years there were no scientific publications on the study of 137Cs contamination of lingonberry. It was demonstrated that there was significant reduction in the density of radioactive soil contamination and 137Cs activity concentration in the aboveground part of lingonberry phytomass and berries in the forests of the research region over the observation period. It was found that the main part of the total 137Cs activity is currently located in the upper (10 cm) layer of the mineral part of the soil — 74.7% where root systems of herbaceous and dwarf-shrub species are concentrated in forest ecosystems. It was established that a considerable content of the radionuclide is retained in the aboveground part of lingonberry phytomass even with low density of radioactive soil contamination. It was found that in 1998, at relatively low value of soil 137Cs contamination density (49±5.6 kBq∙m–2), specific activity of 137Cs in aboveground phytomass of lingonberry was 8043±511 Bq∙kg–1, while in 2021 (value of soil 137Cs contamination density 22±0.3 kBq∙m–2) — 1046±182 Bq∙kg–1. The values of radionuclide transfer coefficients in 1998 were quite significant and varied within wide range: in the air-dry aboveground phytomass from 33.4 to 164.1 m2∙kg–1∙10–3 and in the fresh berries, from 9.5 to 26.0 m2∙kg–1∙10–3. Dependencies between density of radioactive soil contamination and the content of 137Cs in the aboveground part of lingonberry phytomass and berries were calculated, which can be applied in the practice of their harvesting. It was found that lingonberry belongs to the group of plants characterized by the high content of 137Cs in the aboveground vegetative phytomass. Harvesting of lingonberry leaves for the production of medicinal products should be restricted in all areas contaminated with 137Cs. Lingonberry fresh berries can be harvested in areas with a radioactive soil contamination density up to 74 kBq∙m–2.

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.

High-level radioactive waste repository: How Geology combined with societal principles can lead to public acceptance—the German experiment

Using nuclear power for civil energy generation was a promising idea in the second half of the 20th century. Compared to fossil fuels, nuclear power results in almost no CO 2 bearing emissions, which are known to have triggered and enhanced the global climate change. However, nuclear power bears other risks, e.g. environmental and health damage caused by radiation, unwanted release of nuclides being transported by water, accidents of nuclear power plants, and not to mention the possibility of non-intended military use. In any case, generating power from nuclear fission will always produce radiating waste, albeit in small amounts. Due to its longevity, this waste is a significant challenge for scientists, politicians and for the international social community to find a repository, which can be considered safe for millions of years and is accepted by the public. As the general consensus is that the rocks of earth crust’s are the best option for a controlled storage, scientists including geologists, geophysicists and hydrogeologists are looking worldwide for safe underground repository sites. Given different political preconditions, the nations, especially in the European Union, have developed different strategies. The following article intends to describe the current strategy in Germany, which is based on a specific “Act on the search for and selection of a site for a final repository for highly radioactive waste” (in short: Site Selection Act) and attempts to learn from mistakes in the seventies. It is our strong conviction that fundamental geological aspects are as important as essential societal principles in order to gain maximum public acceptance.

Determination of 90Sr in highly radioactive aqueous samples via conversion to a kinetically stable 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid complex followed by concentration–separation–fractionation based on capillary electrophoresis–liquid scintillation

BackgroundThe Fukushima Daiichi Nuclear Power Plant accident (2011) released large amounts of radioactive substances into the environment and generated highly radioactive debris. Post-accident countermeasures are currently in the phase of fuel debris removal, which requires the analysis of radioactive contaminants in the environment and fuel. The spectra of solely β-emitting nuclides, such as 90Sr, overlap; thus, an effective method for nuclide separation is desired. Since conventional methods for high-dose sample analysis pose substantial exposure risks and generate large amounts of secondary radioactive waste, faster procedures allowing for decreased radiation emission are highly desirable. ResultsIn this study, we developed a 90Sr2+ quantitation technique based on liquid scintillation counting (LSC)–coupled capillary transient isotachophoresis (ctITP), along with two-point detection and relying on the rapid concentration, separation, and fractionation of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-complexed 90Sr2+ in a single run. The applicability of our method for the analysis of real-world samples was verified by conducting addition-recovery experiments using a seawater reference material and radioactive liquid waste obtained from the radioactive waste treatment facility at the Japan Atomic Energy Agency. The recovery determined by LSC was 95–113%, indicating successful quantitative analysis. 90Sr recovery was determined to be 90.1% from a contaminated water sample obtained from the Fukushima Daiichi Nuclear Power Plant, which was analyzed using the standard addition of 90Sr. The sensitivity (detection limit = 0.016 Bq) of the proposed method on a radioactivity basis was equal to or higher than that of the conventional method using ion exchange-LSC (0.012–0.07 Bq). Significance and noveltyOur method allows for the handling of high-dose radioactive samples at the microliter level and is substantially faster than conventional ion exchange protocols, whereas ctITP has not been used for practical applications due to inaccurate collection and lack of a suitable chemical system. The concentration–separation–fractionation protocol in ctITP is successful due to the existence of a rare inert Sr2+ complex and precise fractionation. This study establishes a pathway toward safer and more practical analysis of radionuclides.

Special Issue on Robotic, Mechatronic and Information Systems for Decommissioning

The Fukushima Daiichi Nuclear Power Plant accident, triggered by the Great East Japan Earthquake and the tsunami, has had a major impact on societies across the world. The subsequent focus on decommissioning efforts has attracted worldwide attention. It has been consistently asserted since the aftermath of the accident that the decommissioning of the Fukushima Daiichi Nuclear Power Plant will take approximately 30 to 40 years. The promotion of decommissioning work means that we will continue to face the problems with uncertainties in the work, as sometimes referred to as Unknown Unknowns. Typical elemental technologies required in remotely operated robotic systems for decommissioning include mobile mechanisms and their control, handling mechanisms and their control, information communication, operation interface (information presentation and command input), shielding (radiation resistance) and so on. Although many tasks using remotely operated robotic systems have been carried out with noteworthy results, there are lingering issues yet to be clarified. To ensure the safe and effective execution of various types of decommissioning tasks over a period of several decades, continuous research and development of each elemental technology are imperative, and these technologies must be integrated into a system appropriately to the assumed tasks. In addition, human resource development and the transfer of knowledge and experience are also important issues. From such viewpoint, this special issue is titled “Robotic, Mechatronic and Information Systems for Decommissioning.” It contains papers and development reports on robotics, mechatronics, information processing, and information systems technologies relevant to decommissioning work. It also features recent activities of nuclear emergency response organizations. We hope this special issue will acquaint readers with the latest research and development results and organizational activities related to decommissioning. At the same time, we hope that we were able to provide readers interested in robots, mechatronics, and information technology with an opportunity to become aware of the issues and necessary perspectives related to decommissioning and nuclear disasters. Lastly, we would like to thank the editorial board of the Journal of Robotics and Mechatronics, the editorial team of Fuji Technology Press, and the reviewers for their support in the planning and publication of this special issue. Their dedicated efforts are deeply appreciated.

Transport of radioactive materials from terrestrial to marine environments in Fukushima over the past decade

Abstract While 20 % of radionuclides released from the Fukushima Daiichi Nuclear Power Plant accident had been deposited in the terrestrial environment, rivers remain the long-term source for 137Cs, primarily through particulate transfer, from terrestrial to marine ecosystems. In this study, we estimated the suspended 137Cs flux to the ocean at 11 sites in the coastal area between October 2012 and December 2020 to be 17 TBq, based on our long-term monitoring data of concentrations of suspended 137Cs and suspended solids. The cumulative loss of suspended 137Cs from each site to the ocean ranged from 0.1 % to 1.7 % of initial deposition throughout the observation period, depending on the effect of dam lakes and normalized river discharge. The higher loss is also thought to be the large outflow of runoff during the typhoon. The current level of the suspended 137Cs concentrations was lowered to 1/10–1/100 of those immediately after the accident. The average value of the decreasing trend for each site was approximated using the equation: y = a1 e −k 1 t + a2 e −k 2t. The rate constant k 1 is higher in areas with intensive land use, such as pastures, bare land, and water surfaces, and k 2 is lower in urban areas.

Dispersant-enhanced migration of radiocesium among soil size fractions: A novel strategy for volume reduction of radioactively contaminated soil

In the aftermath of the Fukushima Daiichi Nuclear Power Plant accident, a pioneering large-scale decontamination project was initiated, aiming to enable the return of evacuees. This project, the first of its kind in human history, involved the transportation of soils collected during decontamination to interim storage facilities. Before recycling or disposal, these soils undergo processes like volume reduction. However, there's a need for innovative methods to reduce volume effectively and treat secondary wastes more efficiently. The current study explores the impact of a dispersant, sodium hexametaphosphate (SHMP), on the behavior of radiocesium (r-Cs: 137Cs) dynamics in different size fractions of radioactively contaminated soils from Fukushima. The solid-phase speciation analysis of Fukushima soils validated that at least 50% of the 137Cs or other minerals are associated with difficult-to-extract soil phases. Nonetheless, the low 137Cs/133Cs ratio in corresponding soil phases implies a slower r-Cs fixation mechanism. The wet-sieving of r-Cs contaminated soil fraction, < 2 mm, with SHMP, resulted in different soil subfractions (2000–212, 212–53, and < 53 μm). Following SHMP treatment, dispersion of > 92% of 137Cs associated with < 212 μm soil size fractions was observed. The migration of 137Cs towards smaller soil size fractions can be attributed to either SHMP-induced cation exchange or the formation of polyvalent complexes involving SHMP and soil minerals. The condensation of 137Cs in < 212 μm, as induced by SHMP, enabled the subsequent reuse of the larger soil fraction (> 212 μm), which was less contaminated. This study provides a new perspective on the effects of dispersants and contributes to a better understanding of the complex interactions among organic carbon, 137Cs, monovalent and polyvalent cations, and soil functional groups concerning the volume reduction of soils contaminated with r-Cs.

Intra-mediary expertise: Trans-science and expert understanding of the public.

What is the role of experts and their expertise in the context of trans-science, in which issues that are raised in scientific terms cannot be answered by science alone? This article examines the discourses and practices around safety of low-dose exposure to radiation in the ongoing aftermath of the Fukushima Daiichi Nuclear Power Plant accident in Japan in 2011. Following the nuclear fallout, scientific experts and STS scholars in Japan debated what forms of science communication were adequate to address the situation. Ethnographic research and textual analysis of their debates show a shift in emphasis on the role of experts from cultivating 'public understanding of science' for the sake of science and policy to an 'expert understanding of the public' for the sake of the public and its diverse everyday concerns. Two forms of expertise are emerging: 'co-expertise' and 'intra-mediary expertise'. Both are parts of a transition from a paternalistic form of expertise to one that acknowledges the need to engage the public to address issues of scientific uncertainty. However, co-expertise ultimately upholds the existing political structures that shape risk governance, while intra-mediary expertise engages those often excluded from current structures of accountability. Discussion of the potentials and limitations of emerging forms of expertise in Japan show that epistemic justice is not enough. Civic justice that acknowledges diverse publics and their needs must be upheld in the uncertain sphere between science, politics, and everyday life.

Evaluating thyroid cancer risks for nuclear workers related to the Fukushima Daiichi Nuclear Power Plant accident based on LNT theory is problematic.

Evaluating thyroid cancer risks for nuclear workers related to the Fukushima Daiichi Nuclear Power Plant accident based on LNT theory is problematic.

Categorization of disaster-related deaths in Minamisoma city after the Fukushima nuclear disaster using clustering analysis

The medical situation during disasters often differs from that at usual times. Disasters can lead to significant mortality that can be difficult to monitor. The types of disaster-related deaths are largely unknown. In this study, we conducted a survey to categorize the disaster-related deaths caused by a radiation disaster. A total of 520 people living in Minamisoma City, Fukushima Prefecture, at the time of the Fukushima Daiichi Nuclear Power Plant accident, who were certified to have died due to disaster-related causes were surveyed. We divided the participants into those who were at home at the time of the earthquake and those who were in hospitals or facilities when the disaster struck and conducted a hierarchical cluster analysis of the two groups. Disaster-related deaths could be divided into seven groups for those who were at home at the time of the disaster and five groups for those who were in hospitals or facilities at the time of the disaster. Each group showed different characteristics, such as "the group with disabilities," "the group receiving care," and "the group with depression," and it became evident that not only uniform post-disaster support, but support tailored to the characteristics of each group is necessary.

Post-Disaster Community Transition of Psychiatric Inpatients: Lessons from the Fukushima Nuclear Accident.

This study sought to explore factors related to community transition after the mandatory evacuation of psychiatric inpatients to other hospitals owing to the Fukushima Daiichi Nuclear Power Plant accident. A retrospective cohort design was adopted and 391 psychiatric patients were examined. Univariate and multivariate analyses were conducted to confirm the association between the achievement or non-achievement of discharge to community living and their backgrounds (age, gender, evacuation destination, psychiatric diagnoses, and physical complications). Multivariate analysis indicated that patients with psychiatric diagnoses of schizophrenia, schizotypal, and delusional disorders (International Statistical Classification of Diseases and Related Health Problems 10th revision, F20-29), and those with physical diagnoses of the circulatory (I00-95) and digestive (K00-93) systems showed a significant association with the non-attainment of community transition. From these results, we hypothesized that difficulties in the management of medication during and immediately after the extremely chaotic settings of evacuation could have negative effects on the community transitions. Furthermore, another possible concern was that individuals' persistent psychotic status before the accident had been carried over to the destination hospitals. Therefore, pre-disaster daily cooperation across hospitals and challenges for vulnerable psychiatric patients' future community lives are also essential.

Study on the relationship between the dispersal of wild boar (Sus scrofa) and the associated variability of Cesium-137 concentrations in its muscle Post-Fukushima Daiichi Nuclear Power Plant accident

After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011, the wild boar (Sus scrofa) population within the Fukushima Evacuation Zone (FEZ) increased substantially in size and distribution. This growing population and their potential dispersal from the FEZ, where they are exposed to high levels of radionuclides, into the surrounding landscape underscores the need to better understand boar movement patterns in order to establish policies for managing shipping restrictions for boar meat and develop management strategies. In this study, we quantified the genetic population structure of boar in and around Fukushima prefecture using sequence data of the mitochondrial DNA control region and MIG-seq analysis using 348 boar samples to clarify boar dispersal patterns. Among boar samples, seven Asian haplotypes and one European haplotype were detected. The European haplotype originated from hybridization between domestic pigs and native boar in the evacuation zone after the accident and was detected in 15 samples across a broad geographic area. Our MIG-seq analysis revealed genetic structure of boar was significantly different between boar inhabiting the eastern (including FEZ. i.e., East clade) and western (i.e., West clade) regions in Fukushima prefecture. In addition, we investigated the relationships between boar dispersal and Cesium (Cs)-137 activity concentrations in boar muscle using MIG-seq genetic data in Nihonmatsu city, located in the central-northern region of Fukushima. High Cs-137 activity concentrations, exceeding 1000 Bq/kg, in boar muscle had a significantly high probability of belonging to the East clade within localized regions. Thus, our results provide evidence of the spatial scale of dispersal of individuals or offspring of boar from the FEZ. Results of this research also indicate that dispersal of individuals between areas with different Cs-137 contamination levels is one of the biggest factors contributing to variation in Cs-137 activity concentration in boar muscle within localized regions.

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.

Continuing Steady Challenges Involved in the Lifting of Evacuation Orders after the Fukushima Daiichi Nuclear Power Plant Accident.

Steady efforts for recovery and reconstruction after the accident at the Fukushima Daiichi Nuclear Power Plant have been underway for 12.5 y. The present study reports on the world's first-ever efforts for a gradual and safe return to areas contaminated with radiation fallout and reconstruction support by providing an overview of the actual situation regarding the strategy for return, especially with the transition after the lifting of the evacuation order by the Japanese government. A stage-by-stage progression of the evacuation order and lifting strategy is summarized chronologically in the following three phases: the Emergency Phase in 2011, the Reconstruction Phase from 2013 to 2020, and the Challenging Phase for Lifting All the Evacuation Zones from 2023. Through the lifting strategy of the government, the number of evacuees decreased significantly, especially during the Reconstruction Phase, from 152,113 in May 2013 to 37,826 in May 2020. It is crucial to strengthen support for reconstruction and convey an unbiased and accurate understanding of Fukushima Prefecture by developing a concrete strategy for community development and increasing the size of the exchange population.