Nuclear Accident Research Articles

Modeling tritium release to the atmosphere during the Fukushima Daiichi Nuclear Power Plant accident and application to estimating post-accident water system transit times

Abstract During the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident on March 11, 2011, radionuclides such as tritium were released into the environment across Japan, obscuring the natural background signal of tritium in precipitation. This anthropogenic component was rapidly washed out by precipitation according to measurements in Japan. However, the impact of the accident on the natural tritium-based estimation of water system transit times in Fukushima and other prefectures in Japan remains uncertain. For the first time, anthropogenic tritium from the FDNPP accident together with natural tritium were simulated in an atmospheric general circulation model with a good ability to represent tritium variations in daily and monthly precipitation. For the FDNPP accident, we estimate the maximum tritium atmospheric emission of 0.815 PBq with a tritium in precipitation peak of 68.7 Bq/L (582 tritium units) on March 2011 at Fukushima, which are consistent with previous estimations. Using our modeled outputs with tritium measurements, we improve tritium-tracer application for estimating mean transit times of Fukushima surface and groundwater systems impacted by the anthropogenic tritium from the FDNPP accident. While the anthropogenic impact of the FDNPP accident was limited compared to the tritium peak due to the thermonuclear testing, globally modeled tritium in precipitation is useful to apply for other areas of tritium-tracer studies.

The effect of heavy metals on the radiation shielding capabilities of borated polyethylene: A Geant4 study

Abstract Research has increasingly focused on polymers for medical applications due to their beneficial properties. Polyethylene, a common polymer, is extensively used as a neutron shield in radiation-related environments, particularly in hospitals. Recently, borated polyethylene—created by combining polyethylene with 5% boron by weight—has been employed in hospital doors due to its exceptional durability across a wide temperature range and its effective neutron shielding capabilities. Hospital doors must protect against radiation leakage that could endanger patients and staff while also being lightweight, resistant to moisture and chemicals, sound-absorbent, and flexible during manufacturing. Borated polyethylene meets all these criteria, leading many manufacturers to produce hospital doors from borated high-density polyethylene (BHDPE). In this study, the shielding effectiveness of borated polyethylene, enhanced with 5% of heavy metals such as iron, bismuth, and tungsten, was theoretically analyzed using Geant4 against photons and neutrons with energies ranging from 10 keV to 20 MeV. The results indicated that iron-borated high-density polyethylene (Fe-BHDPE) offers the best neutron shielding, followed by tungsten-borated high-density polyethylene (W-BHDPE) and bismuth-borated high-density polyethylene (Bi-HDPE). For photon shielding, Bi-HDPE performed the best. The choice of metal and its proportion in radiation protection doors should be tailored to the specific type of radiation present in the facility, considering potential interactions, surrounding conditions, scattering effects, and any secondary particles that may be produced.

Fukushima twelve years after the nuclear accident

PurposeThis paper analyzes the structure of recovery policies in Fukushima, discusses the current situation of the affected areas and the affected people of Fukushima 12 years after the Fukushima nuclear accident occurred and points out issues concerning revitalization of Fukushima based on the results of field surveys of the affected areas, as well as interviews and questionnaires of the affected people and literature reviews.Design/methodology/approachAfter the Fukushima nuclear accident occurred in March 2011, what policies have been implemented? To what extent have the affected areas of Fukushima been regenerated? To what extent have the affected people of Fukushima rebuilt their lives? What are the issues that need to be addressed for the revitalization of Fukushima? Since the Fukushima nuclear accident occurred, the author has continued to conduct field surveys of the affected areas, as well as interviews and questionnaires of the affected people, and literature review. This paper aims to answer three questions based on the results of these surveys and reviews.FindingsFirst, the nuclear disaster is characterized by its wide-area and long-term nature. Second, recovery of the affected areas by public projects do not have sufficient effect on rebuilding of the lives of the affected people since most of the affected people do not return to the affected areas. Third, it is necessary to establish a legal system for disaster prevention, recovery and revitalization suited to the characteristics of the nuclear disaster in order to promote rebuilding of the lives of the affected people and for the recovery of the affected areas.Originality/valueThere is little literature that has been systematically examined regarding the recovery from the Fukushima nuclear accident. This paper discusses the current status and issues of recovery from nuclear disaster 12 years after the nuclear accident, based on my experiences as the chairperson of the Fukushima Prefecture Recovery Planning Committee and the chairperson of the Recovery Planning Committee in several municipalities where evacuation orders were issued after the Fukushima nuclear accident occurred.

Beyond the Surface: Evaluating the Impacts of Fukushima Nuclear Wastewater Release

Following the 2011 Fukushima nuclear power plant accident in Japan, managing contaminated water became a long-term challenge. In August 2023, Japan began discharging treated atomic wastewater into the Pacific Ocean, sparking global concern. Since nuclear wastewater discharge involves environmental safety, public health, and international relations, understanding various perspectives and presenting scientific data is crucial for formulating reasonable policies. This study aims to analyse the attitudes of different countries towards the Fukushima nuclear wastewater discharge, assess its scientific basis, and explore its economic impact on Japan's fishing industry. The results show that Japan's wastewater discharge complies with international safety standards, based on an evaluation of publicly available data from the Tokyo Electric Power Company and the International Atomic Energy Agency. The analysis encompassed both safety measures and environmental impacts of this specific nuclear wastewater release. Despite scientific studies confirming that the treated nuclear wastewater meets safety standards, ongoing public concerns and geopolitical tensions have caused significant economic impacts on Japan's fishing industry. Therefore, enhanced scientific dialogue and research are needed to effectively address the potential long-term challenges that nuclear wastewater discharge may pose to marine ecosystems and global food safety

In-situ gamma-ray measurement to estimate depth distribution of 137Cs in farmland in Fukushima Prefecture.

Radioactive cesium released into the atmosphere caused by the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011 has contaminated the surrounding area. We confirmed the applicability of in-situ methods to evaluate the depth distribution of 137Cs by employing the ratio of Compton-scattering and photo-peak components (rC) obtained from measured gamma-ray spectra. In the present study, we applied the in-situ method to farmlands in Fukushima Prefecture whose sites were disturbed by decontamination and plowing operations. rC and the net count of the 662-keV photo-peak, npeak, were obtained from gamma-ray spectra measured using a portable CsI detector. Reasonable rC was obtained by removing the contribution of naturally occurring radioactive materials through a simple and versatile procedure. The depth distribution of 137Cs measured using the conventional sampling method was reproduced using the Fermi distribution function. The concentration of 137Cs on the ground surface, N(0), and the depth at which the concentration becomes half of N(0), d1/2, can be described by simple functions of npeak and rC, respectively. We also confirmed that the Monte Carlo simulation is useful to reproduce the present results, taking into account the contribution of 134Cs and the detection system properly.

90Sr and 137Cs distribution in Chornobyl forests: 30 years after the nuclear accident.

The primary aim of this study was to quantify patterns in the distribution of 90Sr and 137Cs activity in pine (Pinus sylvestris L.: 18 sites) and birch (Betula pendula Roth.: 2 sites) forests within the Chornobyl exclusion zone, 30 years after the Chornobyl nuclear power plant (NPP) accident (1986). To achieve this, radionuclide activity concentrations were measured in the mineral and organic soil horizons, the green forest floor (grasses, mosses, and lichens), and trunk wood in forest plots dominated by either pine or birch trees.Our results showed that the geometric mean of the 90Sr aggregated transfer factors from mineral soil to the trunk wood of pine trees (Tag) for Scots pines was 24 x 10-3m2kg-1, which is an order of magnitude higher than the IAEA Handbook (2010)reference value (1.7 x 10-3m2kg-1), which were based on studies conducted after the Kyshtym accident (Ural region, Russia) and in the first years following the Chornobyl accident (Ukraine and Belarus). The observations suggest that the above-ground biomass (soil organic layers, green forest floor, and trees) may contribute more to the 90Sr inventory than the mineral soil at the stand level. In contrast, the 137Cs Tag values for pine and birch stands were consistent with those reported in the literature (ranging from 0.1 to 10 and 0.5-1.1 x 10-3m2kg-1, respectively). Both results align with the known bioavailability of radionuclides from previous studies: low for 137Cs, leading to limited soil depth migration (less than 30cm in the mineral horizon), and higher for 90Sr, resulting in greater soil migration (up to 1m in the mineral horizon). This study highlighted significant correlations between the radionuclides' activity concentrations in the litter layers and their content in the trunk wood of pine trees.

Factors ensuring healthy work environments for municipal office workers in the disaster area after the Fukushima Daiichi nuclear power plant accident: A qualitative analysis

Factors ensuring healthy work environments for municipal office workers in the disaster area after the Fukushima Daiichi nuclear power plant accident: A qualitative analysis

Design of a Low-cost Radiation Weather Station.

Combining a traditional weather station with radiation monitors draws the public's attention to the magnitude of background radiation and its typical variation while providing early indications of unplanned radiological releases, such as nuclear power plant accidents or terrorist acts. Several networks of combined weather and radiation monitoring sensors exist, but these fail to be affordable for broad distribution. This work involves creating an affordable system to accumulate data from multiple locations into a single open-source database. The data collected should thus serve as a friendly database for high school students. The system is designed around an inexpensive sensor package featuring a cup anemometer, wind direction vane, and tip bucket rain gauge. A Raspberry Pi 4 microcomputer interfaces through RJ11 and RJ45 connectors to these and other sensors. Custom-designed circuits were implemented on printed circuit boards supporting sensor chips for temperature, pressure, humidity, and air electrical resistance. The outdoor board communicates with ultraviolet light, soil moisture, and temperature sensors, relaying data using wired connections indoors where a Raspberry Pi 4 and indoor circuit board are located. The indoor board employs wireless internet protocol to communicate with a homemade Geiger-Mueller counter and a consumer-grade temporal radon monitor. The system employs an internet connection to transfer data to a cloud-based storage system. This enables a website with continuously updated pages dedicated to each established system to display collected data. Weatherproofed fused filament fabricated indoor and outdoor cases were designed. Sensor functions were tested for functionality and accuracy.

Molecular simulation on Cs, Rb retention in Na/K-montmorillonite interlayer coupling clay swelling/collapse

A key issue about radioactive waste disposal and nuclear accident contamination control is the retention of radionuclides in clay minerals. The cation (Cs+, Rb+, Na+, K+) selectivity in montmorillonite (Mt) interlayers have not been quantitatively studied. This work employs classical molecular dynamics (CMD) to systematically investigate the interlayer structure, swelling properties, diffusion dynamics, and cation exchange processes. The selectivity of alkali ions within the interlayer space coupled with clay swelling/collapse under different water activity (aw) and cation activity, has been quantified. Both Cs-, Rb-Mt demonstrate a monolayer hydrate configuration as the most stable state. The mobility of intercalated species, as indicated by self-diffusion coefficients, exhibits a stepwise trend with increasing water content. The cationic selectivity within the interlayer follows the order Cs+ > Rb+ > K+ > Na+ at aw = 1.0. The logarithm values of the selectivity coefficients for Cs/Rb relative to Na/K are as follows: logKc(Cs/K) = 0.73, logKc(Cs/Na) = 1.62, logKc(Rb/K) = 0.62, and logKc(Rb/Na) = 1.57 at aw = 1.0. A model correlating selectivity coefficients with water activity has been proposed. It is noted that Cs+ and Rb+ ions tend to accumulate within the interlayer as water activity decreases, and interlayer Rb+ competes with Cs+ for exchange positions at low water activity. These results can be used to quantify cationic partitioning during the remediation of radiocesium contamination in soil and weathering processes of sediments.

Estimation of Strontium-90 Concentrations in Pakistan Using Combination of TBP Solvent Extraction, Precipitation and Cherenkov Counting Methods

90Sr does not exist in nature. Its main sources in the environment are global fallout of past nuclear accidents or nuclear detonations. 90Sr is radiologically significant because of its relatively long physical and biological half-lives and its chemical resemblance to calcium. In order to estimate the radioactivity level of 90Sr around Pakistan Institute of Nuclear Science and Technology (PINSTECH) Islamabad, environmental samples (soil, water, vegetation, and water) and food samples (wheat, milk, poultry) were collected from the different selected sites around PINSTECH within the area of about 12.5 km radius. All samples were pretreated using the guidelines of International Atomic Energy Agency (IAEA) Technical Reports Series No. 295. 90Sr was indirectly determined through its progeny 90Y in secular radioactive equilibrium. 90Y was radiochemically separated using combination of Tri-n-butyl Phosphate (TBP) solvent extraction and precipitation. Finally, the activity was measured on Tri-Carb Liquid Scintillation Counter (LSC) through Cherenkov radiation. The activity concentrations of 90Sr in all samples were too low to be detected by the LSC system, except for a vegetation sample from Rawal Dam where a minimum activity of 0.16 ± 0.04 Bq/kg of fresh weight was found. No considerable activity concentration of 90Sr was found around PINSTECH research facilities.

Performance of the daily fire hazard index within territories contaminated by the Chornobyl nuclear disaster

Performance of the daily fire hazard index within territories contaminated by the Chornobyl nuclear disaster

Factors Associated with Public Health Nurses' Anxiety About Accepting Evacuees During Nuclear Disasters: A Cross-Sectional Study in Oita Prefecture, Japan.

Background/Objectives: The Fukushima Daiichi Nuclear Power Station accident underscored the critical role of public health nurses (PHNs) in managing evacuees during nuclear emergencies. Despite their importance, PHNs often lack sufficient knowledge and experience, which may make them anxious about this role. This study aimed to investigate the factors associated with PHNs' anxiety about accepting evacuees and identify strategies to alleviate this anxiety. Methods: A cross-sectional survey was conducted among 100 PHNs working in Oita Prefecture, Japan, a region designated to receive evacuees in the event of a nuclear disaster. Data were collected via an online questionnaire assessing radiation knowledge, workplace characteristics, and anxiety about accepting evacuees. Univariate and multivariate logistic regression analyses were performed to identify the predictors of anxiety. Results: PHNs working in prefectural offices were 3.4 times more likely to feel anxious about accepting evacuees than those in municipal offices (OR = 3.488, 95% CI = 1.236-10.963, p = 0.023). Awareness of evacuation site responsibilities significantly reduced anxiety (OR = 0.412, 95% CI = 0.134-1.211, p = 0.110). Overall, knowledge of radiation was low, with only 8% correctly identifying the differences between stochastic and deterministic effects. Online training was the preferred format for education. Conclusions: Workplace characteristics and knowledge of evacuation responsibilities significantly influence PHNs' anxiety levels. Addressing knowledge gaps through tailored, accessible training programs, particularly in online formats, is essential. Strengthening preparedness among PHNs could enhance their confidence and ability to manage evacuees effectively during nuclear disasters.

Performance metrics outperform physiological indicators in robotic teleoperation workload assessment

Robotics holds the potential to streamline the execution of repetitive and dangerous tasks, which are difficult or impossible for a human operator. However, in complex scenarios, such as nuclear waste management or disaster response, full automation often proves unfeasible due to the diverse and intricate nature of tasks, coupled with the unpredictable hazards, and is typically prevented by stringent regulatory frameworks. Consequently, the predominant approach to managing activities in such settings remains human teleoperation. Teleoperation can be demanding, especially in high-stress situations, and involves a complex blend of both cognitive and physical workload. We present an experiment to explore a range of physiological and performance-related metrics for workload assessment during robotic teleoperation. Thirty-five participants performed a teleoperation task, during which we manipulated cognitive and physical workload conditions. We recorded multiple metrics, including brain activity using functional Near-Infrared Spectroscopy, galvanic skin responses, cardiovascular responses, subjective workload ratings, task and robot performance data. Our results suggest that robotic teleoperation performance may be the most robust metric for distinguishing between different levels of workload experienced during teleoperation, with most physiological measures becoming insignificant to distinguish high cognitive workload.

Pollution Problems in the Economic Agricultural Sector: Evaluating the Impact on Natural Resources and Solutions for Improvement

In the face of modern global challenges and the growing impacts of anthropogenic activity, the issue of agricultural pollution of natural resources has become a critical issue, especially in countries experiencing ecological and social crises. Ukraine, as one of Europe’s largest agricultural producers, faces unique challenges stemming from the legacy of radiation contamination following the Chornobyl nuclear disaster, intensive land use, and the environmental consequences of military conflict. Our study focuses on analyzing the sources of agricultural pollution, including chemical runoff, pesticides, herbicides, heavy metals, and nutrient leaching, as well as their impacts on the sustainability of agroecosystems, food security, and human well-being. The methodology is based on a systematic analysis of scientific research, agrochemical surveys, monitoring reports, and documents from governmental and non-governmental organizations. The assessment of natural resources was conducted using an integrated approach combining quantitative and qualitative pollution indicators. The results reveal an increasing threat to natural resources in Ukraine due to outdated technologies, radiation contamination, and military activities. Special attention is given to the need for a transition to agroecological farming methods and bioremediation for restoring contaminated lands and water resources. The study contributes to the development of sustainable approaches to managing natural resources and strategic measures to minimize agricultural pollution. The Ukrainian context underscores the relevance of research in countries with transitional economies and unique environmental challenges, making the findings significant for international scientific agendas and environmental policy. Future research perspectives include developing innovative technologies to prevent pollution and enhance the sustainability of agroecosystems to ecological challenges, as well as creating international resource management models based on Ukraine’s experience.

Thyroid doses for the Chornobyl Tissue Bank: improved estimates based on revised methodology and individual residence and diet history.

Increased thyroid cancer incidence has been one of the principal adverse health effects of the Chornobyl (Chernobyl) nuclear power plant accident. Accurate dose estimation is critical for assessing the radiation dose-response relationship. Current dosimetry estimates for individuals from the Chornobyl Tissue Bank (CTB) are based only on the limited information on their places of residence at the time of the accident and/or at the time of surgery for thyroid cancer. The present study aimed to assess whether additional residential and dietary history data collected during personal interviews would substantially impact dose estimates. This paper presents an assessment of thyroid doses from 131I intake for the 197 exposed individuals from the CTB with pathologically confirmed papillary thyroid cancer. Thyroid doses, which had been calculated for these individuals in 2010, were revised in this study using the recently substantially revised 'Thyroid Dosimetry 2020 system for Ukraine' (TDU20). In addition, residence and diet history data were collected during personal interviews with individuals for whom dosimetry-related data were scarce. The arithmetic mean of thyroid doses estimated in this study was 510 mGy (previously 700 mGy), while the median was 81 mGy (previously 120 mGy). A rather wide range of thyroid doses from zero to 11.9Gy (previously up to 15.0Gy) was observed among study participants. The uncertainties in doses were characterized by the geometric standard deviation of 1,000 individual stochastic doses. As a result, the geometric standard deviation varied from 1.3 to 5.3 with an overall arithmetic mean of 2.7 and a median of 2.9. This study clearly showed that the use of individual questionnaire data in dose assessment of individuals who completed personal dosimetry interviews had a noticeable impact on the thyroid dose values: the thyroid doses changed by more than 100 mGy in 31 out of 104 (29.8% of the total) individuals, while such changes due to the use of TDU20 were observed in 18 out of 104 (17.3%) individuals. Clearly, future focused studies using samples from the CTB would benefit from personal interviews to improve dose estimates. Another lesson learned from this study is that whenever a radiation accident occurs, it is important to ask affected people by health and radiation safety authorities to keep records of their own behavior and diet, and, if possible, those of their children.

Audit of preparedness of selected military hospital in the face of biological threats: action research study

IntroductionIn today’s societies, the threats caused by chemical, biological, radiological and nuclear accidents, whether accidental or intentional, have become a great concern. Acquiring knowledge about how to respond to the management of these incidents and the complications caused by them in order to preserve societies and ensure stability is essential. Due to the fact that hospitals play an important role in dealing with the victims of biological threats, this study was conducted with the aim of auditing the preparedness of selected military Hospital in facing biological threats in 2023–2024.MethodsThis applied research was conducted with the participatory action research method in all departments of selected military Hospital during one year from July 2023 to July 2024. The level of biological preparedness of the hospital was investigated using the hospital’s preparedness tool in biological events with 147 items in 8 main dimensions and 20 sub-dimensions, and the weak areas of the hospital (9 areas) were identified. Then, in the hospital audit cycle, using the FOCUS-PDCA model, a program to improve work processes and improve the biological preparedness of different departments of the hospital in the face of accidents and disasters was implemented. The level of biological preparedness of the hospital before and after the implementation of the change was compared and analyzed using SPSS. version 22 software.ResultsThe preparedness in the studied hospital in facing biological threats before the change was 196 out of 294 and the hospital’s biological preparedness percentage was 66.66%, which was in the average range, and after the change, the preparedness score reached 228 and the hospital’s preparedness percentage was 77.55%, which was in the range Well classified. In 9 fields where the level of biological preparedness was moderate and weak, the highest preparedness was created in the field of employees and volunteers with 86.36% and the lowest preparedness was related to the field of corpse management with 50%.ConclusionConsidering the impact of training in improving the hospital’s preparedness program in the face of biological threats, it is suggested that other medical centers include audits in their work plan.

Population shifts during the reconstruction period in areas marked as evacuation zones after the Fukushima Daiichi nuclear power plant accident: a mobile spatial statistics data-based time-series clustering analysis.

An accurate understanding of the population is essential for the development of medical care and social resources. However, the development of transportation networks has increased temporal and spatial fluctuations in the population, making it difficult to accurately forecast medical care demand, especially during disaster recovery. This study examined the population movement in areas affected by the Fukushima Daiichi nuclear power plant accident using demographic data. The target area includes two cities, seven towns, and three villages that are in the evacuation zone. Using a population estimation that reflects changes in population by time of day, which was obtained from a mobile phone company (NTT DOCOMO), we applied clustering analysis to examine the population dynamics over a 4-year period. From 2019 to 2022, the population increased in eight areas and decreased in four areas. The population was further classified into five groups, identifying the unique characteristics and fluctuations of each group. Different regions had different percentages of groups reflecting the characteristics of their populations. The differences among the regions and demographic transition showed the potential to understand the challenges of recovery and to use the data to inform healthcare planning and social policies. This method, which utilizes estimated population data, is also applicable to the study of medical resources and social policies in the event of future disasters and may be useful in analyzing regional characteristics in detail.

Application of the spectral determination method to unified β-, γ- and X-ray spectra

ABSTRACT So far, we have developed the innovative radioactivity quantification technique of spectral determination method (SDM) and applied it to spectra measured with Ge, NaI detectors and liquid scintillation counter (LSC). In the present study we extended the SDM to apply to a unified spectrum composed of LSC and Ge detector, and the number of nuclides has been increased from 8 or 9 to 40. We selected 40 radionuclides from possible radionuclides included in nuclear debris and radioactive wastes in the environment which were produced by the nuclear accident in Fukushima in 2011. We prepared LSC and Ge standard spectra by direct measurements and simulation calculations utilizing the Geant 4.10.3 Monte Carlo simulation tool kit. The derived LSC and Ge spectra for each nuclide were unified to a single spectrum and the 40 sets of them were completed as a unified database. We studied the determination accuracy of the present analysis by examining a composed spectrum made of 40 radionuclides with equal intensities. The SDM result shows that the relative determination uncertainties of 35 nuclides are below 20%. It is also indicated that by removing 3 interfering nuclides the determination accuracy of the other 37 nuclides could be improved.

The summary of risk response on radioactive substances contained in food items in the aftermath of the Fukushima nuclear accident.

The Fukushima Daiichi nuclear power plant accident occurred after the Great East Japan Earthquake on 11 March 2011. The regulations for food items contaminated with radioiodine or radioactive cesium were introduced immediately after the accident by establishing a tentative limit for the contamination level. These regulations excluded or minimized the excessive internal radiation exposure in Japan. Subsequently, the Food Safety Commission of the Japanese Cabinet Office established based on the Food Safety Basic Act evaluated the influence of food items on human health, and the information was reviewed to establish finalized reference values according to the Food Sanitation Act. This study aimed to compile a summary from published sources to examine the risk analysis conducted by the Japanese government over 5 years since the disaster occurred, which was carried out to prevent internal exposure to radioactive substances in food. Findings revealed that items exceeding the reference value were mostly found in the item group not under cultivation/feeding management. In addition, the risk management measures to prevent internal exposure to radioactive substances in food have proven to be effective.

Role of radiation emergency medicine: historical view-a perspective on the past, present, and future.

The more science progresses, the more life and society change. Medicine also changes with the times and the culture. This is also true for radiation emergency medicine, which includes dose-assessment leading to diagnosis, treatment, medical follow-up and prognosis of persons who have developed acute injury or illness due to radioactive contamination or radiation exposure. Before the report of X-rays by Roentgen, there was evidence that X-rays had been emitted from the electrically excited Crookes tube and that skin injury had been caused by the X-rays. Thus, the history of radiation and its exposure started before Roentgen. During the early stage of radiation use, people were simply exposed to radiation but were unaware of any danger. Radioactive materials were found soon after Roentgen's report, and contamination with these materials occurred. Together with the development of science and technology, sophisticated radiation devices were produced, and the use and application of radiation became much enhanced. New radionuclides were found one after another, leading to identification of different qualities of radiation. Development of nuclear physics allowed people to artificially produce radionuclides and to construct a nuclear reactor. After World War II, nuclear power plants were constructed, and related facilities such as nuclear fuel processing, reprocessing and spent fuel storage facilities were built. If radiation accidents or events occur at such facilities, radiation exposure with thermal or chemical burns could occur. Together with the expansion of globalism in the world and division in the society, there are now increasing concerns regarding the malicious usage of radiation by radiological dispersal devices (RDDs) including a dirty bomb. Upon detonation of RDDs, blast and thermal injuries with radiation exposure could be caused. In the present society, the natures of exposure to radiation and contamination with radioactive materials have become much more complicated. Not even mentioning the atomic bomb, the detonation of RDDs also necessitates scenarios of medical responses to complicated injuries and the involvement of numbers of people. This article looks back at the history of radiation and addresses the medical responses to radiation injuries that change with the times.