Daiichi Nuclear Power Plant Incident Research Articles

Simulation of Hypothetical Radiological Accident at Potential Nuclear Power Plant Sites in Malaysia

After any nuclear incident, the main concern for human well-being is the extent of radiation released beyond the site. This study simulated a similar scenario on three potential nuclear power plant sites in Malaysia, using the Fukushima Daiichi Nuclear Power Plant incident as a reference. The computer model Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) was used to simulate and track the movement of air parcels and the dispersion of radioactive emissions. HYSPLIT analyzed the dispersion profile of radioactive materials, revealing that in S1, S2, and S3, the maximum ground dose was 7.9 mSv, 28.0 mSv, and 7.6 mSv, respectively. The maximum activity deposited on the ground was 62 MBq, 210 MBq, and 14 MBq for S1, S2, and S3, respectively. The analysis of ground deposition indicated that S1 covered an estimated area of 1500 km2, S2 covered 3025 km2, and S3 had the largest coverage of approximately 4537 km2. Overall, this study demonstrates that the hypothetical accident would contaminate the vicinity of the three potential nuclear power plant (NPP) sites.

Seismic Performance of Piping Systems of Isolated Nuclear Power Plants Determined by Numerical Considerations

The interest in the seismic performance of nuclear power plants has increased worldwide since the Fukushima Daiichi Nuclear Power Plant incident. In Korea, interest in the seismic safety of nuclear power plants has increased since the earthquake events in Gyeongju (2016) and Pohang (2017). In Korea, studies have been conducted to apply seismic isolation systems to ensure seismic safety while minimizing the design changes to nuclear power plants. Nuclear power plants with seismic isolation systems may have a higher seismic risk due to the failure of the piping system in the structure after a relatively large displacement. Therefore, it is essential to secure the seismic safety of pipes for the safe operation of nuclear power plants. The seismic safety of pipes is determined by seismic fragility analysis. Seismic fragility analysis requires many seismic response analyses because it is a statistical approach to various random variables. Typical numerical conditions affecting the seismic response analysis of pipes are the convergence conditions and mesh size in numerical analysis. This study examined the change in the seismic safety of piping according to the numerical conditions. The difference in the seismic response analysis results of the piping according to the mesh size was analyzed comparatively. In addition, the change in the seismic fragility curve of the piping according to the convergence conditions was investigated.

Usefulness of the whole-body counter for infants and small children (BABYSCAN) as a risk communication tool after the Fukushima Daiichi nuclear power plant incident.

Responding to the radiation-related concerns of parents/guardians with infants/small children is an important public health issue for regional recovery after radioactive contamination. This study summarizes the results of a systematic internal contamination screening of infants/small children, aged 0–6 years, using BABYSCAN and individual counselling sessions with physicians about radiation concerns from 2014 to 2018 in Minamisoma City. Of 3,114 participants, no one was found to have internal contamination with radioactive caesium with a detection limit of 50 Bq/body. The questionnaire survey showed a decreasing trend of concerns about food contamination and playing outside as possible causes of internal contamination over time. Because people’s concerns were diverse in counselling sessions, individual responses are required. This study showed that examinations using BABYSCAN provide an opportunity for direct dialogue between the parents/guardians of infants/small children and experts. This can be considered a model case for risk communication conducted by the local government after a radioactive contamination incident.

Low dose of external exposure among returnees to former evacuation areas: a cross-sectional all-municipality joint study following the 2011 Fukushima Daiichi nuclear power plant incident

There is little information on the radiation dose levels of returnees to areas once designated as legal no-go zones, after evacuation orders were lifted subsequent to the 2011 Fukushima Daiichi nuclear power plant incident. This study used individual radiation dosimeter monitoring and a location history survey to conduct the most recent dose assessment of external exposure among returnees to former no-go zones. We specifically determined correlation and agreement between external doses and the air dose rate in residential areas and quantified both uncertainty and population variability of the observed data using Monte Carlo (MC) simulation methods. A total of 239 voluntary participants across ten municipalities were analysed; their representativeness of all affected municipal populations was confirmed in terms of air dose rate distribution in residential areas. We found that individual doses were statistically significantly correlated with the air dose rate based on government airborne monitoring. This implies that airborne monitoring can provide sufficient information for understanding dose levels among such returnees. The MC simulations demonstrated that the mean of the annual dose in 2019 (including natural background doses) was 0.93 (95% uncertainty interval 0.53–1.76) mSv, with limited variation between municipalities. As of 2019, this implies that doses from external exposure were very low among returnees and would be associated with a very low likelihood of physical effects according to current scientific consensus. However, these results should be taken with caution due to several study limitations, including selection and participation biases. Regardless, its findings will enhance societal debates about how both individual-dose and government airborne monitoring practices should operate in the future and how the government can improve the public outlook for radiation doses in incident-affected areas.

Economic Loss Due to Reputation Damage: A New Model and Its Application to Fukushima Peaches

AbstractConsumers have responded negatively to agricultural products originating from the Fukushima prefecture after the 2011 Fukushima Daiichi nuclear power plant incident. These consumers’ behavioural changes have caused substantial economic losses for the producers located in contaminated regions through reductions in market prices, consumption quantities and market shares. Remarkably, these losses are observed also for uncontaminated products, posing an opportunity for research in reputation damage. However, existing literature is very rare on empirical modeling of such losses. We utilise the Dixit–Stiglitz demand framework to derive a simple but efficient empirical model that uses market data to quantify reputation damage. This model estimates changes in the perceived quality of a product originating in contaminated regions in relation to those products originating from other competing regions. The model also measures subsequent loss in market share for those products grown in contaminated regions. In our application to Fukushima, results suggest that consumers’ valuation of peaches from Fukushima decreased dramatically (between 22.5% and 23.6%) in the year the nuclear accident occurred, but rapidly recovered in the following years. The results also show that the degree of impact varies across wholesale markets. Fukushima farmers lost about 13.1–18.9% of sales due to reputation damage. Estimates from our proposed models deliver meaningful information in the context of policy interventions such as transfer programmes financed by gainers to compensate reputation losses.

Impact of decontamination on individual radiation doses from external exposure among residents of Minamisoma City after the 2011 Fukushima Daiichi nuclear power plant incident in Japan: a retrospective observational study

Following the Fukushima incident, radiation doses from external exposure accounted for the majority of the total doses. Although countermeasures are being implemented, with the aim of reducing radiation exposure, little information is available on the effects of decontamination on individual doses among the residents of radioactively contaminated areas. To evaluate the effectiveness of the decontamination measures in reducing individual doses, and to examine the influence of the timing of decontamination and the district, data were analysed for 18 392 adults and 3 650 children in Minamisoma City, Fukushima, who participated in a voluntary screening programme using individual radiation dosimeters (Glass Badge) between June 2013 and September 2016. The dose reduction rates (DRR) were calculated for one year by comparing the first and last three-month measurement results between areas with and without decontamination. Using a regression approach and Monte Carlo simulation, the dose reduction rate by decontamination eliminating the effect of physical decay (DRRd′) was also estimated as a function of the timing of the decontamination and the dose at the time of starting the decontamination. The annual DRR in areas with decontamination for both adults and children were significantly higher than those in areas without decontamination, depending on the timing of decontamination: 31%–36% for 2013–14 for adults in decontamination areas and 33%–35% for children in decontamination areas, compared to 12%–23% and 13%–23% for adults and children in areas without decontamination, respectively. There was a positive correlation between DRRd′ and individual doses, and DRRd′ was estimated at 30%–40% for adults and children with doses of 3 mSv y−1 in 2013 and 2014. This study demonstrated that decontamination does lower individual doses from external exposure. The higher the dose at the time of starting the decontamination, the greater the dose reduction rate by decontamination, regardless of the timing of the decontamination. Our study confirms that decontamination was useful for high-dose areas in the later phases of the incident.

Combating 'fake news' and social stigma after the Fukushima Daiichi Nuclear Power Plant incident.

Combating 'fake news' and social stigma after the Fukushima Daiichi Nuclear Power Plant incident.

A Comparative Survival Analysis Between Evacuees and Nonevacuees Among Dialysis Patients in Fukushima Prefecture After Japan's 2011 Fukushima Nuclear Incident.

There has been little research on the health consequences of evacuation in the disaster context. A comparative analysis of survival between evacuated and nonevacuated hospital dialysis patients was conducted following Japan's Fukushima Dai-ichi nuclear power plant incident, which occurred on March 11, 2011. The study included 554 patients (mean age: 70.9) receiving dialysis therapy at one of the Tokiwakai Group hospitals-all of which are located in and around Iwaki City, approximately 50 km from the Fukushima nuclear plant-as of the incident date. The patients' survival after the incident was tracked until March 3, 2017. Significant differences in mortality rates between postincident evacuees and nonevacuees were tested using the Bayesian survival analysis with Weibull multivariate regression. Out of 554 dialysis patients, 418 (75.5%) were evacuated after the incident. The postincident mortality rate (adjusted for covariates) of evacuees was not statistically significantly different from that of nonevacuees. The hazard ratio was 1.17 (95% credible intervals: 0.77-1.74). If performed in a well-planned manner with satisfactory arrangements for appropriate selection of evacuees and their transportation, evacuation could be a reasonable option, which might save more lives of vulnerable people.

Combating 'fake news' and social stigma after the Fukushima Daiichi Nuclear Power Plant incident-the importance of accurate longitudinal clinical data.

Combating 'fake news' and social stigma after the Fukushima Daiichi Nuclear Power Plant incident-the importance of accurate longitudinal clinical data.

Influence of Ectomycorrhizal Colonization on Cesium Uptake by Pinus densiflora Seedlings

Radionuclides were deposited at forest areas in eastern parts of Japan following the Fukushima Daiichi Nuclear Power Plant incident in March 2011. Ectomycorrhizal (EM) fungi have important effects on radiocaesium dynamics in forest ecosystems. We examined the effect of colonization by the EM fungus Astraeus hygrometricus on the uptake of cesium (Cs) and potassium (K) by Pinus densiflora seedlings. Pine seedlings exhibited enhanced growth after the EM formation due to the colonization by A. hygrometricus. Additionally, the shoot Cs concentration increased after the EM formation when Cs was not added to the medium. This suggests that A. hygrometricus might be able to solubilize Cs fixed to soil particles. Moreover, the shoot K concentration increased significantly after the EM formation when Cs was added. However, there were no significant differences in the root K concentration between EM and non-EM seedlings. These results suggest that different mechanisms control the transfer of Cs and K from the root to the shoot of pine seedlings.

Empirical studies on strategic interaction among municipality governments over disaster waste after the 2011 Great East Japan earthquake

Strategic interaction among governments has become a major focus of empirical and theoretical work in public economics. NIMBY is one application of the literature. In the present paper, we apply the NIMBY model to the disposal of disaster debris after the Great East Japan Earthquake when there was substantial concern over radioactive contamination following the Fukushima Daiichi Nuclear Power Plant incident. We empirically test the strategic interaction among municipality governments. We find strong evidence of such interaction. That is, in deciding whether to accept disaster waste, the municipality governments appear to keep a close eye on other municipality governments’ choices.

Psychometric Evaluation of the Japanese Version of the Posttraumatic Stress Disorder Checklist in Community Dwellers Following the Fukushima Daiichi Nuclear Power Plant Incident

We investigated the psychometric properties of the Japanese version of the Posttraumatic Stress Disorder Checklist–Stressor Specific Version (PCL-S) using baseline data from the Fukushima Health Management Survey. A total of 26,332 men and 33,516 women aged 16 and above participated in this study. Participants lived in the Fukushima evacuation zone in Japan and experienced the Great East Japan Earthquake and nuclear power plant (NPP) incident. The PCL-S was used to assess participants’ posttraumatic stress disorder (PTSD) symptoms. In addition, we described participants and tested the validity of the PCL-S by administering the Kessler Six-item Screening Scale for Psychological Distress (K6) and assessing education; employment; self-rated health; sleep satisfaction; experiencing the earthquake, tsunami, and NPP incident; and bereavement as a result of the disaster. PCL-S scores exhibited a positively skewed, slightly leptokurtic distribution. Confirmatory factor analysis revealed that the five-factor model was a better fit than were the three- or four-factor models. The PCL-S and its subscales had high Cronbach’s alpha coefficients. The PCL-S scores had weak-to-moderate correlations with history of mental illness, bereavement, experiencing the tsunami, experiencing the NPP incident, self-rated health, and sleep satisfaction, as well as a strong correlation with psychological distress. There were significant gender and age differences in PCL-S scores. Overall, this study confirmed the psychometric properties of the PCL-S, including the score distribution, factor structure, reliability, validity, and gender and age differences. Thus, the Japanese version of the PCL-S would be a useful instrument for assessing the PTSD symptoms of community dwellers who have experienced traumatic events.

Postnuclear disaster evacuation and chronic health in adults in Fukushima, Japan: a long-term retrospective analysis

ObjectiveJapan's 2011 Fukushima Daiichi Nuclear Power Plant incident required the evacuation of over a million people, creating a large displaced population with potentially increased vulnerability in terms of chronic health...

Post-nuclear disaster evacuation and survival amongst elderly people in Fukushima: A comparative analysis between evacuees and non-evacuees

BackgroundConsidering the health impacts of evacuation is fundamental to disaster planning especially for vulnerable elderly populations; however, evacuation-related mortality risks have not been well-investigated. We conducted an analysis to compare survival of evacuated and non-evacuated residents of elderly care facilities, following the Great East Japan Earthquake and subsequent Fukushima Dai-ichi nuclear power plant incident on 11th March 2011. ObjectiveTo assess associations between evacuation and mortality after the Fukushima nuclear incident; and to present discussion points on disaster planning, with reference to vulnerable elderly populations. MethodsThe study population comprised 1,215 residents admitted to seven elderly care facilities located 20–40km from the nuclear plant in the five years before the incident. Demographic and clinical characteristics were obtained from medical records. Evacuation histories were tracked until mid 2013. Main outcome measures are hazard ratios in evacuees versus non-evacuees using random-effects Cox proportional hazards models, and pre- and post-disaster survival probabilities and relative mortality incidence. ResultsExperiencing the disasters did not have a significant influence on mortality (hazard ratio 1.10, 95% confidence interval: 0.84–1.43). Evacuation was associated with 1.82 times higher mortality (95% confidence interval: 1.22–2.70) after adjusting for confounders, with the initial evacuation from the original facility associated with 3.37 times higher mortality risk (95% confidence interval: 1.66–6.81) than non evacuation. ConclusionsThe government should consider updating its requirements for emergency planning for elderly facilities and ensure that, in a disaster setting, these facilities have the capacity and support to shelter in place for at least sufficient time to adequately prepare initial evacuation.

Testing for presence of radioactivity in BC Pacific Ocean’s seafood supply


 Abstract: Due to the Fukushima Daiichi Nuclear power plant incident in March 2011, large quantities of contaminated water were released to the Pacific Ocean in Japan. The severity of contamination on the marine environment is unclear, therefore, the public is concerned with the possible internal radiation exposure from ingesting contaminated seafood products caught in the Pacific Ocean. This study was aimed to investigate the presence or absence of gamma radioactivity in commonly consumed seafood products from B.C. In total, ten different species of fish and three different species of shellfish were selected for analysis. For each species of fish, two samples were collected and each sample was from a different local seafood market. For each species of shellfish, ten samples were collected from three different sources. Using the portable GR-135 Plus gamma ray spectrometer, the samples were tested and analyzed for the presence of Fukushima radionuclides, particularly Cesium-137 (Cs-137) and Cesium- 134 (Cs-134).Based on the analyzed fish and shellfish, no gamma radiation was detected. The detector did not identify any gamma radiation over the normal background readings.

Lightweight aerial vehicles for monitoring, assessment and mapping of radiation anomalies

The Fukushima Daiichi nuclear power plant (FDNPP) incident released a significant mass of radioactive material into the atmosphere. An estimated 22% of this material fell out over land following the incident. Immediately following the disaster, there was a severe lack of information not only pertaining to the identity of the radioactive material released, but also its distribution as fallout in the surrounding regions. Indeed, emergency aid groups including the UN did not have sufficient location specific radiation data to accurately assign exclusion and evacuation zones surrounding the plant in the days and weeks following the incident. A newly developed instrument to provide rapid and high spatial resolution assessment of radionuclide contamination in the environment is presented. The device consists of a low cost, lightweight, unmanned aerial platform with a microcontroller and integrated gamma spectrometer, GPS and LIDAR. We demonstrate that with this instrument it is possible to rapidly and remotely detect ground-based radiation anomalies with a high spatial resolution (<1 m). Critically, as the device is remotely operated, the user is removed from any unnecessary or unforeseen exposure to elevated levels of radiation.

Fukushima's children

Nearly 2 years on from the 2011 Fukushima Daiichi nuclear power plant incident—and as a recent article highlights the continuing after-effects of fallout from the Japan atomic bomb in 1945—Zena Nyakoojo reports on the some of the latest concerns about ionising radiation currently affecting the region.

Role of nurses in a nuclear disaster: experience in the Fukushima Dai‐ichi nuclear power plant accident

A severe earthquake occurred in Japan on 11 March 2011. The giant tsunami devastated many coastal communities in eastern Japan and caused the Fukushima Dai-ichi nuclear power plant incident. The Japanese government conducted a large-scale survey of residents affected by the nuclear and natural disasters in Fukushima prefecture and in response to the government's request, H University dispatched a Radiation Exposure Research Team to Fukushima. This article explains the activities of the Radiation Exposure Research Team and the role of nurses in a nuclear disaster. As a nurse in the field of radiation medicine, our role is to protect the health of those affected and to reduce their anxiety. In addition, as the persons responsible for implementing these projects, it is also necessary that we educate and foster the development of medical care personnel with the appropriate knowledge and skills to carry out the measures required.

Methods For Estimating The Atmospheric Radiation Release From The Fukushima Dai-Ichi Nuclear Power Plant

WHat: A multidisciplinary group of scientists and engineers from academia/private industry/ government/national laboratories in the United States, Japan, and Europe convened to discuss the Fukushima Dai-ichi nuclear power plant incident, observations of the radiation deposition patterns, and methods to use these measurements to better estimate the total radioactive material released into the atmosphere. WHEn: 22–23 February 2012 WHErE: National Center for Atmospheric Research, Boulder, Colorado O n 11 March 2011, a 9.0-magnitude earthquake off the east coast of Japan and subsequent tsunami caused widespread damage in northeastern Japan and resulted in a cooling system failure, partial reactor core meltdown, and radiation release from the Fukushima Dai-ichi nuclear power plant (FD-NPP). Following the devastating earthquake and tsunami that severely damaged the nuclear power plant in Fukushima, Japan, an unknown quantity of radioactive material was released into the air and water surrounding the crippled nuclear power plant. Assessments of the remaining nuclear fuel following the incident have allowed the scientific community to approach a consensus on the total amount of radioactive material released from the FD-NPP. What is still unclear, however, is the timing of the releases and how much of the radioactive material was released into the atmosphere versus directly into the nearby ocean. The complexity of this disaster—which included disabled observation systems; multiple intermittent explosive releases of radioactive materials combined with a long-duration continuous release of radiation at an unknown rate; and changes in boundary layer depth, wind speed/direction, and precipitation in the region surrounding the FD-NPP—complicates these estimates. An accurate estimate of the radiation released into the atmosphere from the FD-NPP is necessary for scientists and government officials to make informed decisions that impact the estimation of long-term doses and the safety of people living and working near Fukushima. While extensive observational surveys of the radiation fallout pattern have been made, using these measurements to estimate the magnitude and timing of radiation released into the atmosphere versus the ocean remains a challenging undertaking. Despite the large number of observations available, they cover only a small fraction of the area and time period. Consequently, current estimates include a large degree of uncertainty, resulting in correspondingly large uncertainties regarding the total amount of radiation fallout and associated environmental impacts, which significantly hamper the Japanese

Monitoring of aerosols in Tsukuba after Fukushima Nuclear Power Plant incident in 2011

Artificial radionuclides were released into the atmosphere by the Fukushima Dai-ichi Nuclear Power Plant incident after a strong earthquake on 11 March 2011. Aerosol monitoring at the Geological Survey of Japan, Tsukuba, was started 20d after the incident. Radionuclides such as 99Mo/99mTc, 132Te/132I, 129mTe/129Te, 131I, 137Cs, 136Cs, 134Cs, 140Ba/140La, 110mAg, and 95Nb were observed and, with the exception of 137Cs and 134Cs, these radionuclides decreased to below the limit of detection in the middle of June. The activity ratio of atmospheric 134Cs/137Cs in aerosols decreased over time almost following physical decays. Therefore, the 134Cs/137Cs activity ratio in the averaged air mass in this study could be regarded as homogeneous although those of several reactors in the Nuclear Power Plant were not ascertained. A further research on the released 137Cs and 134Cs would be necessary for the sedimentology of lake sediment.