A study of the protective actions for a hypothetical accident of the Bushehr nuclear power plant at different meteorological conditions

Radiation and Environmental Biophysics - In this work, protective actions have been studied assuming a hypothetical severe accident of the Bushehr nuclear power plant at different meteorological...     

After Fukushima: managing the consequences of a radiological release

Even amidst the devastation following the earthquake and tsunami in Japan that killed more than 20,000 people, it was the accident at the Fukushima Daiichi nuclear power plant that led the country's prime minister, Naoto Kan, to fear for "the very existence of the Japanese nation." While accidents that result in mass radiological releases have been rare throughout the operating histories of existing nuclear power plants, the growing number of plants worldwide increases the likelihood that such releases will occur again in the future. Nuclear power is an important source of energy in the U.S. and will be for the foreseeable future. Accidents far smaller in scale than the one in Fukushima could have major societal consequences. Given the extensive, ongoing Nuclear Regulatory Commission (NRC) and industry assessment of nuclear power plant safety and preparedness issues, the Center for Biosecurity of UPMC focused on offsite policies and plans intended to reduce radiation exposure to the public in the aftermath of an accident. This report provides an assessment of Japan's efforts at nuclear consequence management; identifies concerns with current U.S. policies and practices for "outside the fence" management of such an event in the U.S.; and makes recommendations for steps that can be taken to strengthen U.S. government, industry, and community response to large-scale accidents at nuclear power plants.     

Consequences and countermeasures in a nuclear power accident: chernobyl experience

Despite the tragic accidents in Fukushima and Chernobyl, the nuclear power industry will continue to contribute to the production of electric energy worldwide until there are efficient and sustainable alternative sources of energy. The Chernobyl nuclear accident, which occurred 26 years ago in the former Soviet Union, released an immense amount of radioactivity over vast territories of Belarus, Ukraine, and the Russian Federation, extending into northern Europe, and became the most severe accident in the history of the nuclear industry. This disaster was a result of numerous factors including inadequate nuclear power plant design, human errors, and violation of safety measures. The lessons learned from nuclear accidents will continue to strengthen the safety design of new reactor installations, but with more than 400 active nuclear power stations worldwide and 104 reactors in the Unites States, it is essential to reassess fundamental issues related to the Chernobyl experience as it continues to evolve. This article summarizes early and late events of the incident, the impact on thyroid health, and attempts to reduce agricultural radioactive contamination.     

Monosodium glutamate for accidental,retrospective, and medical dosimetry using electron spin resonance

The risk of a radiation episode has increased in the last years due to several reasons. In case of a nuclear incident, as with the use of an improvised nuclear device, determination of the radiation doses received by the victims is of utmost importance to define the appropriate medical treatment or to monitor the late effects of radiation. Dose assessment in case of accidents can be performed using commonplace materials found in the accident area. In this paper, the dosimetric properties of monosodium glutamate are investigated by electron spin resonance spectroscopy (ESR), for retrospective and accidental dosimetry. The spectroscopic parameters were optimized to achieve higher signal intensity and better signal-to-noise ratio. As a result, the lowest detectable dose was 0.1 Gy, and monosodium glutamate showed a linear dose–response curve for doses ranging from 0.1 Gy to 10 kGy. The dosimetric signal was monitored from minutes right after irradiation, until 1 year. No changes in the signal intensity were observed over this period, meaning that doses could be assessed immediately after radiation exposure and can still be reconstructed long after the accident. This property also implies that late effects due to victim’s radiation exposure could be better monitored and understood. ESR signal intensity for samples irradiated with a photon energy below 100 keV was decreased by only 27% and no dose-rate dependence was noticed. Therefore, the ability to measure doses as low as 0.1 Gy, the high stability of the dosimetric signal, as well as independence on dose rate, tissue equivalence, low-cost, and wide commercial availability make monosodium glutamate a very good dosimetric material not only for retrospective and accidental but also for medical dosimetry.     

Ecological aspects of the chernobyl nuclear plant disaster

The partial meltdown of the 1000MW reactor in Chernobyl and the massive release of radionuclides into the environment is the first large-scale contamination of a geographically significant area by a power-generating civilian nuclear plant. It will have a long term effect on the human population, agriculture and the environment. Previous cases of accidental contamination of the environment on such a scale were connected with the disposal of reprocessed nuclear waste or the release of radioactivity from atmospheric and underground tests of nuclear weapons. One such contamination, which provides important lessons in the wake of the Chernobyl disaster, was linked with the explosion of the nuclear waste storage facility near Kyshtym in the Cheliabinsk region of the Soviet Union in 1958. It resulted in the creation of a special 'exclusion zone', resettlement of local populations and special construction projects designed to prevent the distribution of radioactivity over even larger areas.     

Analysis of the contribution of forest pathways to the radiation exposure of different population groups in the Bryansk region of Russia

The experience gained in the aftermath of serious radiation accidents shows that forests are an important source of external and internal exposure of the affected population. This paper presents the results of an assessment of the major radiological consequences for forests of Russia, most heavily contaminated after the Chernobyl nuclear power plant (ChNPP) accident. Illustrated in the Novozybkovsky district of the Russian Federation, the significance of different forest exposure pathways is estimated and the doses resulting from forest pathways are compared with the doses from agricultural products. It has been found that the contribution of mushrooms and berries to the internal doses of the population, relative to the doses from agricultural products, varied from 10–15% in 1987 to 40–45% in 1996. The results indicate large differences in internal exposure of members of the ”critical groups” and ”normal population”, increasing with time after deposition. Data are presented that give information on the contribution of forests to the collective doses of inhabitants of the area under consideration. It has been shown that for 10 years after the accident (1987–1996), the contribution of forest products to the collective dose of the rural population living in contaminated forests of the Novozybkovsky district, amounts to about 20% (213 person Sv) of the total collective dose of internal and external exposures. However, a potential impact of these products including the dose from exported products is much higher and might reach 659 person Sv. It has been found that in the long-term after the ChNPP accident, serious attention should be given to forest countermeasures, and restoration strategies should be selected on the basis of a combined analysis of the effectiveness of forest and agricultural countermeasures. Received: 16 March 2000 / Accepted: 10 September 2000     

The disaster at Japan's Fukushima-Daiichi nuclear power plant after the March 11, 2011 earthquake and tsunami, and the resulting spread of radioisotope contamination

On March 11, 2011 eastern Japan was struck by a magnitude 9.0 earthquake and an enormous tsunami, over 13 m in height, which together killed over 20,500 people and resulted in the evacuation of over 320,000 people from the devastated areas. This paper describes the damage sustained by the Fukushima-Daiichi nuclear power plant during this unpredicted major natural disaster and the events that happened in the months after this accident. The events occurring at the Fukushima-Daiichi nuclear power plant, the actions taken to minimize the effects of the damage to the plant and to protect the public, and the points at which the responses proved to be inadequate all offer lessons that will be of value to those planning for and responding to future natural disasters and accidents in Japan and around the world.     

Learning from the 2011 Great East Japan Disaster: insights from a special radiological emergency assistance mission

On March 11, 2011, the eastern portion of Japan was struck by a massive earthquake and tsunami that killed more than 15,700 people, left thousands of others hurt or missing, and caused widespread destruction. In addition, the Great East Japan Disaster seriously damaged the Fukushima Dai-ichi nuclear power station, knocking out power, severely affecting communications, and causing a loss of cooling to some reactor cores. Significant quantities of radioactive materials were released, a "no go" zone was created around the crippled reactors, and thousands of people were evacuated. With concern about the radiological emergency growing, one of Japan's largest hospital and healthcare groups issued a request for assistance to a U.S.-based international disaster relief organization. After consultations with the Japanese, a special Radiological Emergency Assistance Mission was assembled. The mission, which traveled to Japan in April 2011, had several aims: (1) to rapidly assess the situation on the ground, (2) to exchange information, experiences, and insights with Japanese colleagues, and (3) to provide radiological information and practical refresher training to Japanese healthcare professionals and first responders. In addition to achieving these aims and laying the groundwork for future cooperation, the mission produced dozens of insights and lessons. These have potential relevance not only for future large-scale radiation accidents, but also for radiological and nuclear terrorism situations. They also have more general relevance for emergency planning, preparedness, and response. In this article, several of the most salient insights and lessons are highlighted.     

Carbon-14 dynamics in rice: an extension of the ORYZA2000 model

Carbon-14 (¹⁴C) is a radionuclide of major interest in nuclear power production. The Fukushima accident changed the public attitude on the use of nuclear energy all over the world. In terms of nuclear safety, the need of quality-assured radiological models was emphasized by many international organizations, and for models used by decision-makers (i.e. regulatory environmental models and radiological models), a moderate conservatism, transparency, relative simplicity and user friendliness are required. Because the interaction between crops and the environment is complex and regulated by many feedback mechanisms, however, these requirements are difficult to accomplish. The present study makes a step forward regarding the development of a robust model dealing with food contamination after a short-term accidental emission and considers a single crop species, rice (Oryza sativa), one of the most widely used rice species. Old and more recent experimental data regarding the carbon dynamics in rice plants are reviewed, and a well-established crop growth model, ORYZA2000, is used and adapted in order to assess the dynamics of ¹⁴C in rice after a short-term exposure to ¹⁴CO₂. Here, the model is used to investigate the role of the genotype, management and weather on the concentration of radiocarbon at harvest.     

The risk of leukaemia in young children from exposure to tritium and carbon-14 in the discharges of German nuclear power stations and in the fallout from atmospheric nuclear weapons testing

Towards the end of 2007, the results were published from a case–control study (the “KiKK Study”) of cancer in young children, diagnosed <5 years of age during 1980–2003 while resident near nuclear power stations in western Germany. The study found a tendency for cases of leukaemia to live closer to the nearest nuclear power station than their matched controls, producing an odds ratio that was raised to a statistically significant extent for residence within 5 km of a nuclear power station. The findings of the study received much publicity, but a detailed radiological risk assessment demonstrated that the radiation doses received by young children from discharges of radioactive material from the nuclear reactors were much lower than those received from natural background radiation and far too small to be responsible for the statistical association reported in the KiKK Study. This has led to speculation that conventional radiological risk assessments have grossly underestimated the risk of leukaemia in young children posed by exposure to man-made radionuclides, and particular attention has been drawn to the possible role of tritium and carbon-14 discharges in this supposedly severe underestimation of risk. Both ³H and ¹⁴C are generated naturally in the upper atmosphere, and substantial increases in these radionuclides in the environment occurred as a result of their production by atmospheric testing of nuclear weapons during the late 1950s and early 1960s. If the leukaemogenic effect of these radionuclides has been seriously underestimated to the degree necessary to explain the KiKK Study findings, then a pronounced increase in the worldwide incidence of leukaemia among young children should have followed the notably elevated exposure to ³H and ¹⁴C from nuclear weapons testing fallout. To investigate this hypothesis, the time series of incidence rates of leukaemia among young children <5 years of age at diagnosis has been examined from ten cancer registries from three continents and both hemispheres, which include registration data from the early 1960s or before. No evidence of a markedly increased risk of leukaemia in young children following the peak of above-ground nuclear weapons testing, or that incidence rates are related to level of exposure to fallout, is apparent from these registration rates, providing strong grounds for discounting the idea that the risk of leukaemia in young children from ³H or ¹⁴C (or any other radionuclide present in both nuclear weapons testing fallout and discharges from nuclear installations) has been grossly underestimated and that such exposure can account for the findings of the KiKK Study.     

Study on public acceptance of nuclear power plants: Evidence from China

Abstract

This empirical study evaluated the public acceptance of nuclear-power plants in China. A conceptual framework was proposed to explain the factors affecting nuclear-power acceptance based on antecedent variables, including social-media-use frequency, social-media information trust, nuclear-power knowledge, nuclear-accident knowledge, and risk-and-benefit perception. An empirical study was operated based on the Haiyang nuclear-power plant by conducting a face-to-face survey among residents who use social-media platforms near the plant. The frequency of social-media-use and the trust on social-media information promote individuals’ knowledge about nuclear power and nuclear accidents, leading to risk and benefit perception. Finally, benefit perception results in nuclear-power acceptance among the individuals. Implications and suggestions for future research are discussed.     

A preliminary assessment of the consequences for inhabitants of the UK of the Chernobyl accident

The accident with the nuclear power reactor at Chernobyl in the USSR resulted in the release of substantial quantities of radioactive material and subsequent increases in radioactivity in the environment in many countries. In this paper the situation in the UK is considered and, from the preliminary monitoring measurements, the major routes of exposure of the population are identified and quantified. For the most part exposures in the UK are within variations in levels of natural background radiation to be found in Europe. An exception is the dose likely to have been received by the thyroids of young people in the north of the UK. From reported measurements of I-131 in milk it is predicted that thyroid doses up to 10-20 times the annual doses received from 'normal' natural background radiation might have affected young children drinking fresh cows' milk. The ways in which this component of exposure could have been reduced and the criteria that govern decisions as to whether or not to implement counter-measures are discussed. The importance of I-131 in milk as a route of exposure of the population to radioactivity is a feature that the Chernobyl accident has in common with the Windscale accident in the UK in 1957, and underlines the importance of milk-producing regions in relation to reactor-sitting policy.     

切尔诺贝利核事故对区域景观格局及生境质量的影响

灾难地景观格局及生境质量演化特征研究对于评估灾难破坏力及其滞后性,揭示人类活动对自然环境的影响机制具有重要意义。基于Landsat系列遥感影像提取切尔诺贝利隔离区景观类型结构,借助景观指数和InVEST模型刻画研究区近49年来的景观格局和生境质量演化轨迹,使用CA-Markov模型模拟核事故对区域生态景观的影响。研究表明：（1）切尔诺贝利核事故改变了隔离区原有的景观结构,导致耕地、建设用地等人为景观数量大幅缩减,土地利用程度显著下降,但核事故未对隔离区当前的景观结构造成实质性负面影响;（2）切尔诺贝利核事故致使隔离区人为干扰减少,植被连通性和集聚度提升,景观格局总体向好发展;（3）隔离区的设立扭转了区内生境质量恶化趋势,由耕地形成的低生境质量区域迅速转变为草地、林地等高生境质量区域,区内生境质量极大改善;（4）切尔诺贝利核事故使得区内高生境质量区域占比提升34%,改变了原有以耕地、建设用地不断扩张为主线的景观演化轨迹和生境质量不断退化的发展趋势。     

Microbial aerosol generation during laboratory accidents and subsequent risk assessment

AIM: To quantify microbial aerosols generated by a series of laboratory accidents and to use these data in risk assessment. METHODS AND RESULTS: A series of laboratory accident scenarios have been devised and the microbial aerosol generated by them has been measured using a range of microbial air samplers. The accident scenarios generating the highest aerosol concentrations were, dropping a fungal plate, dropping a large bottle, centrifuge rotor leaks and a blocked syringe filter. Many of these accidents generated low particle size aerosols, which would be inhaled into the lungs of any exposed laboratory staff. Spray factors (SFs) have been calculated using the results of these experiments as an indicator of the potential for accidents to generate microbial aerosols. Model risk assessments have been described using the SF data. CONCLUSIONS: Quantitative risk assessment of laboratory accidents can provide data that can aid the design of containment laboratories and the response to laboratory accidents. SIGNIFICANCE AND IMPACT OF THE STUDY: A methodology has been described and supporting data provided to allow microbiological safety officers to carry out quantitative risk assessment of laboratory accidents.     

Design of a protective shield for a radiological emergency intervention using Monte Carlo simulation and an anthropomorphic phantom

Due to the increasing use of radioactive sources, new challenges appear for the protection of humans and the environment against ionizing radiation. Thus, organizations handling these sources must be endowed with plans how to react in case of any radiological emergency situations. Monte Carlo simulations are among the most widely employed methods used for the management and reconstruction of radiological incidents and accidents. In this work, results of a Monte Carlo simulation study with the Geant4 simulation toolkit using a digital anthropomorphic phantom are reported. The investigated scenario included an emergency intervention carried out inside the ionization cell of the National Institute of Agronomic Research (NIAR) of Tangier/Morocco, which houses a ⁶⁰Co gamma irradiator. In this scenario, a radiological incident was assumed where the source cage of the gamma irradiator is stuck in the guide tube and not completely inserted into its storage container. The objective of this work was to design a radiation shield to protect an operator during the emergency intervention and make sure that any radiation exposure is below the recommended dose limits, taking into account the date of occurrence (which determines the activity of the source at the time of the emergency situation) of the accident and economic aspects of shielding design. In this work, the maximum time available for the operator to accomplish the operation intervention while remaining protected is calculated. The results obtained show that the shielding prototype developed gives the operator a time between 3 and 300 s, depending on shielding design. It is concluded that shielding of the type investigated in the present study will allow any facility to manage the assumed emergency scenario, should it occur.

     

Retrospective dosimetry after criticality accidents using low-frequency EPR: a study of whole human teeth irradiated in a mixed neutron and gamma-radiation field

In the context of accidental or intentional radiation exposures (nuclear terrorism), it is essential to separate rapidly those individuals with substantial exposures from those with exposures that do not constitute an immediate threat to health. Low-frequency electron paramagnetic resonance (EPR) spectroscopy provides the potential advantage of making accurate and sensitive measurements of absorbed radiation dose in teeth without removing the teeth from the potential victims. Up to now, most studies focused on the dose-response curves obtained for gamma radiation. In radiation accidents, however, the contribution of neutrons to the total radiation dose should not be neglected. To determine how neutrons contribute to the apparent dose estimated by EPR dosimetry, extracted whole human teeth were irradiated at the SILENE reactor in a mixed neutron and gamma-radiation field simulating criticality accidents. The teeth were irradiated in free air as well as in a paraffin head phantom. Lead screens were also used to eliminate to a large extent the contribution of the gamma radiation to the dose received by the teeth. The EPR signals, obtained with a low-frequency (1.2 GHz) spectrometer, were compared to dosimetry measurements at the same location. The contribution of neutrons to the EPR dosimetric signal was negligible in the range of 0 to 10 Gy and was rather small (neutron/gamma-ray sensitivity in the range 0-0.2) at higher doses. This indicates that the method essentially provides information on the dose received from the gamma-ray component of the radiation.     

Radioecological indexes of fallout measurements from the Fukushima nuclear accident

Fallout from the Fukushima nuclear accident has been monitored for about 1 month in Thessaloniki, Northern Greece. Three different radionuclides, one short-lived, one relatively long-lived and one long-lived fission product were identified in air, grass and milk samples. The ¹³¹I, ¹³⁷Cs and ¹³⁴Cs activity concentrations in air reached 497, 145 and 126 μBq m⁻³, respectively on 4 April, 2011. These radionuclides are of particular concern regarding their transfer from the environment to population through the ingestion pathways for the assessment of the Fukushima accident consequences. Radioecological indexes (eco-indexes) of fallout measurements in the air–grass–cow-milk–man pathway for ¹³¹I were determined, as they are related to radiological impact of the Fukushima derived radionuclides on the public and environment.     

<Superscript>131</Superscript>I age-dependent inhalation dose in Southern Poland from Fukushima accident

A general method for calculating doses absorbed from isotopes released in nuclear accidents is presented. As an example, this method was used to calculate doses for inhabitants of Southern Poland due to inhalation of ¹³¹I released due to the Fukushima nuclear plant accident. ¹³¹I activity measurements in the air of that region provided the basis for the study. The proposed model is based on a complex biokinetic model for iodine merging the Leggett model developed in 2010 with the human respiratory tract and gastrointestinal tract models recommended by the International Commission on Radiological Protection (ICRP). This model is described here, and it is demonstrated that resulting dose estimates are consistent with those obtained using the ICRP methodology. Using the developed model, total doses were calculated for six age groups of both genders, for gaseous and aerosol fractions alike. The committed effective dose, H ₅₀, for an adult man reached 16 nSv, which is lower than 0.001% of the background dose. The dose for the thyroid of an adult reached 0.33 μSv, which corresponds to circa 0.0007% of the dose to the population of Southern Poland after the Chernobyl nuclear plant accident.     

Population dose near the Semipalatinsk test site

To determine the consequences of atmospheric atomic bomb tests for the population in the surroundings of the former nuclear weapons test site near Semipalatinsk in Kazakhstan, a pilot study was performed by an international cooperation between Kazakh, French, Czech and German institutions at two villages, Mostik and Maisk. Together with Kazakh scientists, eight experts from Europe carried out a field mission in September 1995 to assess, within the framework of a NATO supported project, the radiological situation as far as external doses, environmental contamination and body burden of man were concerned. A summary of the results obtained is presented. The actual radiological situation near the test site is characterized by fallout contaminations. Cs was found in upper soil layers in concentrations similar to those of the global fallout. Also Sr, Am and Co were observed. The resulting present dose to the population is low. Mean external doses from soil contamination for Maisk and Mostik (0.60–0.63 mSv/ year) presently correspond to mean external doses in normal environments. Mean values of the annual internal doses observed in these two villages are below 2 μSv/year for ⁹⁰Sr. For other radionuclides the internal doses are also negligible. Received: 12 March 1998 / Accepted in revised form: 1 August 1998     

Farm accidents in children.

OBJECTIVE--To examine the problem of accidental injury to children on farms. DESIGN--Prospective county based study of children presenting to accident and emergency departments over 12 months with injuries sustained in a farm setting and nationwide review of fatal childhood farm accidents over the four years April 1986 to March 1990. SETTING--Accident and emergency departments in Aberystwyth, Carmarthen, Haverfordwest, and Llanelli and fatal accidents in England, Scotland, and Wales notified to the Health and Safety Executive register. SUBJECTS--Children aged under 16. MAIN OUTCOME MEASURE--Death or injury after farm related accidents. RESULTS--65 accidents were recorded, including 18 fractures. Nine accidents necessitated admission to hospital for a mean of two (range one to four) days. 13 incidents were related to tractors and other machinery; 24 were due to falls. None of these incidents were reported under the statutory notification scheme. 33 deaths were notified, eight related to tractors and allied machinery and 10 related to falling objects. CONCLUSIONS--Although safety is improving, the farm remains a dangerous environment for children. Enforcement of existing safety legislation with significant penalties and targeting of safety education will help reduce accident rates further.