Topographical classification of dose distributions: implications for control for worker exposure.

This paper deals with classification of dose distributions of nuclear workers based on antikurtosis (Q) and entropy coefficients (K) and their relationship presented in QK-diagrams. It is shown that determination of the most appropriate distribution to adopt, for a specific data set of a wide range of input data, requires building and analysing QK-diagrams for distributions of logarithms of individual doses. Actual dose distributions for emergency and occupational exposure situations were then considered, as well as doses for one day of work during clean-up and routine activities. It is shown that, in all cases, three types of distributions of logarithms of individual doses were present: normal, Weibull and Chapeau. The location of the representation point of a dose distribution reflects the degree of dose control of the group of workers whose individual doses are collectively displayed in the QK-diagram. The more the representation point of the analysed distribution of the logarithms of the individual dose of a given contingent of workers deviates from the point of the lognormal distribution, the more there was intervention in the process of individual dose accumulation. Thus, QK-diagrams could be used to develop a dose control function. It is shown that the hybrid lognormal distribution, which is widely used in the field of radiation safety, for the purpose of approximation of real dose distributions, is unable to satisfactorily describe many dose distributions arising in aftermath operations and occupational exposure.

European decision support modelling of long-term external doses received in inhabited areas contaminated by a nuclear power plant accident - 2: Post deposition contaminant mobility on outdoor surfaces.

To enable estimation of time-integrated external doses to persons staying in an inhabited area radioactively contaminated by aerosols and gases released in connection with a large nuclear power plant accident, additional knowledge to that described in the first part of this paper is needed on the post-deposition migration of different types of contaminants on the various relevant types of environmental surface. This part of the paper describes how the migration processes are modelled dynamically in the European standard inhabited area dose model, ERMIN, and presents the newest parametric datasets. It is explained how the total information in both parts of the paper may be used to estimate doses received over time by populations in radioactively contaminated inhabited areas.

European decision support modelling of long-term external doses received in inhabited areas contaminated by a nuclear power plant accident - 1: Initial relative dose rate contributions from different contaminated outdoor surfaces.

Dose prediction tools making use of existing knowledge on the environmental behaviour of radiocontaminants are essential for justification and optimisation of recovery countermeasure strategies for contaminated inhabited areas. In this context, one necessary requirement is to estimate the relative initial contaminant distribution on different types of surfaces in the environment and the resultant initial dose rates to humans staying in the environment. This paper reports on the latest parametric refinements in this context for use in the ERMIN inhabited area dose model, which is an integral part of the European emergency management decision support systems ARGOS and RODOS.

Source term estimation using multiple xenon isotopes in atmospheric samples.

Algorithms that estimate the location and magnitude of an atmospheric release using remotely sampled air concentrations typically involve a single chemical or radioactive isotope. A new Bayesian algorithm is presented that makes discrimination between possible types of releases (e.g., nuclear explosion, nuclear power plant, or medical isotope production facility) an integral part of the analysis for samples that contain multiple isotopes. Algorithm performance is demonstrated using synthetic data and correctly discriminated between most release-type hypotheses, with higher accuracy when data are available on three or more isotopes.

INDIVIDUAL RADIOLOGICAL MONITORING AFTER MAJOR RELEASES OF RADIONUCLIDES TO THE ENVIRONMENT. / INDYVIDUAL'NYI RADIOLOGIChNYI MONITORYNG PISLIa ZNAChNYKh VYKYDIV RADIONUKLIDIV U NAVKOLYShNIe SEREDOVYShchE.

Nuclear installations may contain a large inventory of radioactive material and an emergency caused by an accident, natural disaster, or malevolent act may cause uncontrolled releases of radionuclides to the environment. The paper presents a brief overview of individual radiological monitoring in case of major releases of radionuclides to the environment and introduces the new Report 92 of the International Commission on Radiation Units and Measurements (ICRU) on Radiation Monitoring for Protection of the Public after Major Releases of Radionuclides to the Environment. The Report was prepared taking into account the results of the research «Development of the program for radiation and hygienic monitoring for the radiological protection of human under radiation accidents and acts of nuclear terrorism¼ which was carried out in the internal dosimetry laboratory of the NRCRM of NAMS of Ukraine in 2016-2018. The Report Committee was headed by the scientific supervisor of the research, the Committee consisted of leading experts from UK, Italy, China, Germany, Russia, Slovenia, United States, Ukraine, Japan, and experts from the International Atomic Energy Agency. The preparation of the Report was supported by the US Environmental Protection Agency, US Nuclear Regulatory Commission, US Department of Energy, National Academy of Medical Sciences of Ukraine, and Radiation Protection Institute of the ATS of Ukraine.

Indicadores citogenéticos para la identificación de exposición a radiación ionizante en humanos / Cytogenetic indicators for the identification of ionizing radiation exposure in humans

La biodosimetría citogenética se aplica en la evaluación médica de las personas involucradas en situaciones radiológicas anormales, con el fin de evaluar las dosis recibidas, el peligro inminente para la salud y aplicar los tratamientos médicos más adecuados. Además, contribuye al esclarecimiento de sucesos cuando existen dudas respecto a los resultados de la dosimetría física por dosímetros defectuosos, no calibrados o ausentes. Es el método más preciso de dosimetría biológica, ya que existe una relación matemática que permite calcular la dosis, establecer el grado de homogenidad de la exposición y, en caso de exposiciones no homogéneas, establecer la fracción del cuerpo irradiada y la dosis que recibió esa fracción mediante la cuantificación del número y tipos de aberraciones cromos¢micas y de micronúcleos y su distribución en los linfocitos de la sangre periférica. Para este análisis se establecen las relaciones dosis-efecto y un sistema automatizado para el cálculo de las dosis de radiación recibidas. Actualmente se está desarrollando un proyecto conjunto Universidad de Costa Rica-Hospital San Juan de Dios, con el objetivo de explorar los efectos cromosómicos de la radiación, en pacientes expuestos por razones el objetivo de explorar los efectos cromosómicos de la radiación, en pacientes expuestos por razones terapéuticas y atendidos en este hospital. De igual modo, se hará la curva de calibración dosis-respuesta in vitro para rayos gama y se validar  mediante la intercomparación con el Laboratorio de Dosimetría Citogenética de Centro para la Protección e Higiene de las Radiaciones de Cuba...

Root causes and impacts of severe accidents at large nuclear power plants.

The root causes and impacts of three severe accidents at large civilian nuclear power plants are reviewed: the Three Mile Island accident in 1979, the Chernobyl accident in 1986, and the Fukushima Daiichi accident in 2011. Impacts include health effects, evacuation of contaminated areas as well as cost estimates and impacts on energy policies and nuclear safety work in various countries. It is concluded that essential objectives for reactor safety work must be: (1) to prevent accidents from developing into severe core damage, even if they are initiated by very unlikely natural or man-made events, and, recognizing that accidents with severe core damage may nevertheless occur; (2) to prevent large-scale and long-lived ground contamination by limiting releases of radioactive nuclides such as cesium to less than about 100 TBq. To achieve these objectives the importance of maintaining high global standards of safety management and safety culture cannot be emphasized enough. All three severe accidents discussed in this paper had their root causes in system deficiencies indicative of poor safety management and poor safety culture in both the nuclear industry and government authorities.

Allocation of scarce resources after a nuclear detonation: setting the context.

The purpose of this article is to set the context for this special issue of Disaster Medicine and Public Health Preparedness on the allocation of scarce resources in an improvised nuclear device incident. A nuclear detonation occurs when a sufficient amount of fissile material is brought suddenly together to reach critical mass and cause an explosion. Although the chance of a nuclear detonation is thought to be small, the consequences are potentially catastrophic, so planning for an effective medical response is necessary, albeit complex. A substantial nuclear detonation will result in physical effects and a great number of casualties that will require an organized medical response to save lives. With this type of incident, the demand for resources to treat casualties will far exceed what is available. To meet the goal of providing medical care (including symptomatic/palliative care) with fairness as the underlying ethical principle, planning for allocation of scarce resources among all involved sectors needs to be integrated and practiced. With thoughtful and realistic planning, the medical response in the chaotic environment may be made more effective and efficient for both victims and medical responders.

Medical response to a nuclear detonation: creating a playbook for state and local planners and responders.

For efficient and effective medical responses to mass casualty events, detailed advanced planning is required. For federal responders, this is an ongoing responsibility. The US Department of Health and Human Services (DHHS) prepares playbooks with formal, written plans that are reviewed, updated, and exercised regularly. Recognizing that state and local responders with fewer resources may be helped in creating their own event-specific response plans, subject matter experts from the range of sectors comprising the Scarce Resources for a Nuclear Detonation Project, provided for this first time a state and local planner's playbook template for responding to a nuclear detonation. The playbook elements are adapted from DHHS playbooks with appropriate modification for state and local planners. Individualization by venue is expected, reflecting specific assets, populations, geography, preferences, and expertise. This playbook template is designed to be a practical tool with sufficient background information and options for step-by-step individualized planning and response.

Potential nuclear and radiological incidents: a summary for clinicians.

Most clinicians will go their entire career without seeing a patient who has been involved in a nuclear or radiological incident, and many health care professionals feel ill equipped to respond to such incidents. To add to this difficulty, the medical response that is most appropriate for such an event varies, depending on the type of incident. As part of an effort to address these and other challenges for the medical community, the Centers for Disease Control and Prevention has developed a quick-reference for clinicians (based on the consensus of numerous stakeholders) that summarizes the key differences between various types of potential nuclear and radiological incidents in relation to some key medical response concerns. This paper is not intended for a clinical audience, but rather presents the and describes the framework upon which the is based, providing the health physics community with a clinical perspective of these events.

Classification of events with an off-site radiological impact at the Sellafield site between 1950 and 2000, using the International Nuclear Event Scale.

The paper assesses unplanned operational events at the Sellafield nuclear installation, formerly Windscale and Calder Works, in Cumbria, England, over the period 1950-2000 that had, or could have had, radiological implications for members of the general public. A unified system of off-site impact rating has been developed using a site-specific application of the International Nuclear Event Scale (INES) that is applied retrospectively to events since the start of operations at the site in 1950. Published and unpublished sources of information have been used to assemble what the authors believe to be a complete list of events over the period that would now be assessed as INES level 3 or above on the basis of off-site impact. The last such event occurred in 1984. The exercise also demonstrates that it is possible to apply the current INES rating scheme to a wide variety of radiological events.

An analysis of 45 years of reported overexposure incidents in Texas, 1956 to 2001.

Sources of ionizing radiation are commonly encountered in a wide variety of modern work settings. The controls in place to ensure the safe use of these sources have proven to be quite effective, as events involving occupational doses in excess of established limits are quite rare. Nonetheless, instances of doses in excess of established limits, commonly referred to as "overexposures," do occur, but the rarity of such events has resulted in a body of scientific knowledge that consists essentially of sporadic case reports. In this study, incident reports describing radiation overexposure events recorded in Texas from the years 1956 to 2001 were obtained and recorded into a computerized database using a pre-established set of codes. The data were then analyzed for the identification of possible trends or commonalties. During the 45-y period of study, overexposure events accounted for 50% (n = 3,796) of all the radiation-related incidents recorded in Texas for the time period (n = 7,534). Of the overexposure events, 65% (n = 2,342) resulted in the actual deposition of energy in the individual exposed. The remainder were determined to be doses recorded only by a personal dosimetry device. In most of the cases where doses were actually delivered to an individual, the doses were less than 0.05 Sv (5 rem). In only 0.5% of the cases (n = 13) were doses greater than 1 Sv (100 rem). The predominant sources reported as involved in the events included 192Ir, 60Co, and 137Cs. The information derived from the analysis may serve as a basis for a variety of interventions, such as preventative education activities, regulatory modifications, and the possible re-design of equipment identified as commonly associated with such events. The results of the study can also assist in the training of health care providers, as the recognition of common causes and sources of overexposures and subsequent treatments can be forecasted and summary treatment protocols developed.

Long-term genetic effects of radiation exposure.

To date, there has been little experimental knowledge on the genetic risks of human exposure to ionising radiation for humans. Recent data suggest that hypervariable tandem repeat minisatellite loci provide a useful and sensitive experimental approach for monitoring radiation-induced germline mutation in humans. Here, I review the results of studies on minisatellite mutation rates in human populations exposed to radioactive fallout after the Chernobyl accident and nuclear weapon tests in Kazakhstan.

Radiation disasters and children.

The special medical needs of children make it essential that pediatricians be prepared for radiation disasters, including 1) the detonation of a nuclear weapon; 2) a nuclear power plant event that unleashes a radioactive cloud; and 3) the dispersal of radionuclides by conventional explosive or the crash of a transport vehicle. Any of these events could occur unintentionally or as an act of terrorism. Nuclear facilities (eg, power plants, fuel processing centers, and food irradiation facilities) are often located in highly populated areas, and as they age, the risk of mechanical failure increases. The short- and long-term consequences of a radiation disaster are significantly greater in children for several reasons. First, children have a disproportionately higher minute ventilation, leading to greater internal exposure to radioactive gases. Children have a significantly greater risk of developing cancer even when they are exposed to radiation in utero. Finally, children and the parents of young children are more likely than are adults to develop enduring psychologic injury after a radiation disaster. The pediatrician has a critical role in planning for radiation disasters. For example, potassium iodide is of proven value for thyroid protection but must be given before or soon after exposure to radioiodines, requiring its placement in homes, schools, and child care centers. Pediatricians should work with public health authorities to ensure that children receive full consideration in local planning for a radiation disaster.

The 1951-98 experience of the Paris Institut Curie Radiopathology Unit: a preliminary report.

From 1 January 1951 to 30 June 1998, 696 patients presented spontaneously or were referred to the French Institut Curie Radiopathology Unit following a more or less severe accidental irradiation. Of these, 568 patients came from France, while 128 were sent by various foreign countries. The very great majority of irradiation accidents occurred in the workplace, particularly in industry. Interestingly, 'non-nuclear' industry was responsible for three times more events than the nuclear industry. While incidental irradiation of the public by lost radioactive sources was exceedingly rare in France, it seemed to be more frequent in our cohort of foreign patients. Radiation phobia accounted for about 10% of cases in the French cohort, but the number of cases did not seem to increase with time. Overall, the accrual of patients over time appears to be stable, with 10 to 25 new cases consulting each year. Fortunately, a majority of cases corresponded to low-level irradiation (and even no irradiation at all). In the French cohort, only 21.6% of patients, showing deterministic effects, required some form of treatment, with 4.9% considered as 'severe' cases. Not unexpectedly, more patients required treatment in the foreign cohort (35.2%), with 24.2% of severe cases, including four deaths. The main features of this database are consistent with the data previously reported by the IAEA, UNSCEAR and REAC/TS. Although the number of severe cases is small, it should still be considered to be too high, especially as most of these accidents could have been easily avoided if a few basic radioprotection rules had been fully respected.

Radiation accidents: lessons learnt for future radiological protection.

PURPOSE: To review major radiation accidents that have occurred over a 50 year period. To identify common factors, since feedback may prevent recurrence. METHODS: Accidents are classified according to the difficulties involved in their management and to the delay between their occurrence and their recognition. RESULTS: The rate of severe accidents increases with time, especially those involving the public, and accidents are not always immediately recognized. The real number of serious unrecognized accidents is unknown. Human factors, such as lack of elementary safety rules and inadequate training, play a major role in most of the accidents occurring in industry and in the medical field. CONCLUSIONS: Common sense could have prevented many severe accidents that resulted in deaths and serious injuries. Delay in the identification of accidents results in severe consequences. Pre-planning is essential and may minimize the severity and the deterioration of the situation. Research efforts in the field of medical handling of severely radiation-injured victims should be maintained.

[What kind of accidents can happen in a nuclear power plant]. / Quels accidents peuvent survenir dans une centrale nucléaire?

The lessons drawn from real reactor accidents are of great value. The safety approach in France relies on defence in depth and takes into account accidents in the plant design, completed by a probabilistic approach and experience feedback. Ultimate procedures are implemented on the basis of severe accidents studies which include core melting or partial containment defect, in order to mitigate their consequences even if they are improbable, and to enable a proper implementation of emergency planning countermeasures. The accident hypothesis and consequences are considered to draw the emergency planning procedures. Off site countermeasures, such as in house-confinement, limited evacuation or iodine distribution, are efficient in limiting the consequences for the public. Experience feedback, in association with a proactive vigilance and prevention policy, is developed in order to detect and correct in a proactive way the root causes of any deviation, even minor, so as to avoid multiple failures and ensure safety.

[Radiation accidents in the world]. / Les accidents d'irradiation dans le monde.

Irradiation accidents may unfortunately occur in all fields of activities, whether they are medical, industrial or scientific. They are usually classified in two categories, depending on the number of people involved: large-scale accidents on one hand and, on the other hand, events limited to small groups, mostly workers. The first are very rare, but well-documented. The latter occur more often, but no comprehensive report is yet available, especially for those with benign consequences. Whatever their seriousness, all these situations deserve careful analysis in order to draw appropriate conclusions and improve prevention. Although the number of radiation-related deaths is low (approximately 1 per year, during the last forty years, in Western countries), the frequency of such accidents remains constant, while the applications for the use of radiation increase. Analysis of accidents shows that most of the serious consequences might have been avoided or limited. This, once again, stresses the need of precise rules for every occupation involving ionizing radiation.