Deviation from Mendelian transmission of autosomal SNPs can be used to estimate germline mutations in humans exposed to ionizing radiation

We aimed to estimate the rate of germline mutations in the offspring of individuals accidentally exposed to Cesium-137 ionizing radiation. The study included two distinct groups: one of cases, consisting of males and females accidentally exposed to low doses of ionizing radiation of Cs137, and a control group of non-exposed participants. The cases included 37 people representing 11 families and 15 children conceived after the accident. Exposed families incurred radiation absorbed doses in the range of 0.2 to 0.5 Gray. The control group included 15 families and 15 children also conceived after 1987 in Goiânia with no history of radiation exposure. DNA samples from peripheral blood were analyzed with the Affymetrix GeneChip® CytoScanHD™ to estimate point mutations in autosomal SNPs. A set of scripts previously developed was used to detect de novo mutations by comparing parent and offspring genotypes at the level of each SNP marker. Overall numbers of observed Mendelian deviations were statistically significant between the exposed and control groups. Our retrospective transgenerational DNA analysis showed a 44.0% increase in the burden of SNP mutations in the offspring of cases when compared to controls, based on the average of MFMD for the two groups. Parent-of-origin and type of nucleotide substitution were also inferred. This proved useful in a retrospective estimation of the rate of de novo germline mutations in a human population accidentally exposed to low doses of radiation from Cesium-137. Our results suggested that observed burden of germline mutations identified in offspring was a potentially useful biomarker of effect to estimate parental exposure to low doses of IR and could become an important marker suitable for biomonitoring human population exposed to environmental mutagens.

Ionising radiation risk perception through mental models: towards radiological emergency preparedness

In case of a chemical, biological, radiological, or nuclear emergency, there are recommended or required behaviours to be adopted by the public, e.g. go inside, stay inside, stay informed. The initial response can be crucial to outcomes, all the while recognising that changes may be needed as the emergency progresses. The recent coronavirus pandemic demonstrated how the course of action taken by authorities endorsing these protective behaviours early on can save thousands of lives. Factors that determine response success include public compliance with authorities' recommendations and cooperation between experts and rescuers. In particular, the way rescuers perceive the risks of ionising radiation hazards will influence their preparedness to respond in case of a radiological or nuclear emergency. Having found no previous studies on radiological hazard and risk perception amongst rescuers in Portugal, mental models were used as a descriptive approach. The target groups were firefighters and the military formally trained to deal with radiation hazard emergencies. Their representations of radiological hazards and risks were analysed in the light of an expert model built ad hoc. The results show several overlays between experts and rescuers on the understanding of radiation hazards and potential risks. We conclude that the main gap between radiation risk perceptions by rescuers and experts involves the concepts and mechanisms of radiation contamination and its spread among individuals, in particular, if persons exposed to radioactive sources may also become a radioactive source themselves. This gap can have practical implications for an emergency response.

Uncertainties in atmospheric dispersion modelling during nuclear accidents

Predictions of the atmospheric dispersion of radionuclides accidentally released from a nuclear power plant are influenced by two large sources of uncertainty: one associated with the meteorological data employed, and one with the source term, i.e. the temporal evolution of the amount and physical and chemical properties of the release. A methodology is presented for quantitative estimation of the variability of the prediction of atmospheric dispersion resulting from both sources of uncertainty. The methodology, which allows for efficient calculation, and thus is well suited for real-time assessment, is applied to a hypothetical accidental release of radionuclides.

OFF-SITE RADIOLOGICAL DOSE ASSESSMENT IN A SEVERE NUCLEAR ACCIDENT OF APR1400

Shin Kori unit 3 of Korea Hydro and Nuclear Power Co. is the pressurized water reactor of advanced power reactor 1400 (APR1400) in the Republic of Korea. A hypothetical accident was assumed for Shin Kori unit 3 to perform the time-dependent dose calculations along with the release rates of radionuclides to the environment. In order to assess the accident scenarios, Radiological Assessment System for Consequence Analysis code was used, which is a set of tools for emergency response applications developed by US Nuclear Regulatory Commission. A straight-line Gaussian model was used for the near-field atmospheric calculations and a Lagrangian Gaussian puff model was used for the far-field simulations where released radioactive materials to the environment were transported, dispersed and deposited. In this study, long-term station blackout in spring, summer, autumn and winter season was considered in 2016-2018 based on reactor condition and seasonal effects. It was found that the worst season is the spring and the worst scenario found during the evening time of spring in 2017. The calculated maximum values of total effective dose equivalent (TEDE) and thyroid committed dose equivalent (CDE) are 22 mSv and 390 mSv, respectively, around 5 km of precautionary action zone (PAZ) in 2 days after the accident. According to Korean regulations on urgent public protective actions, for indoor sheltering, the criteria are 10 mSv in 2 days. For public evacuation 50 mSv in 1 week and iodine prophylaxis should be introduced if thyroid protection level is 100 mSv. Calculated values of TEDE are more than double and thyroid CDE is almost four times in the PAZ compared with Korean regulations; hence, it was found that indoor sheltering and supply of iodine prophylaxis should be executed for short/mid-term protective measures. In this situation, indoor sheltering should be decided by off-site emergency management center, which was accountable for emergency decision-making process in nuclear accident under nuclear safety and security commission in Korea.

Radioactive Games? Radiation Hazard Assessment of the Tokyo Olympic Summer Games

We conducted a comprehensive radiation hazard assessment of the Tokyo Olympic Games (Tokyo 2020, postponed to 2021). Our combined experimental and literature study focused on both external and internal exposure to ionizing radiation for athletes and visitors of the Games. The effective dose for a visit of 2 weeks ranges from 57 to 310 μSv (including flight dose). The main contributors to the dose are cosmic radiation during the flights (approximately 10-81%), inhalation of natural radon (approximately 9-47%), and external exposure (approximately 8-42%). In this complex exposure, anthropogenic radionuclides from the Fukushima nuclear accident (2011) always play a minor role and have not caused a significant increase of the radiological risk compared to pre-Fukushima Japan. Significantly elevated air dose rates were not measured at any of the Tokyo Olympic venues. The average air dose rates at the Tokyo 2020 sites were below the average air dose rates at the sites of previous Olympic Games. The level of radiological safety of foods and water is very high in Japan, even for athletes with increased water and caloric demands, respectively.

Summary and recommendations from the workshop 'Integrating measurements and atmospheric-dispersion modelling to enhance the UK response to radiological atmospheric releases'

Effective preparedness and response to an atmospheric release following a radiological incident relies on information concerning the source, transport and eventual removal of the contaminant. A notable improvement to emergency preparedness and response in the UK to airborne releases of radiological contaminants can be achieved through the integration of information sources, in particular environmental radiological measurements and atmospheric-dispersion modelling. A one-day workshop was organised by the UK Met Office and the University of Bristol, comprising private nuclear facility operators, public bodies, academia and others, on 6 February 2020 in Bristol, UK. The workshop reviewed the current capabilities and challenges of measurements and modelling of airborne radiological contaminants and their integration, and identified improvement pathways. This memorandum provides a summary of recommendations from the workshop.

Inhalational Exposure Causes Radioactive Material Uptake for Multiple Workers

Seven individuals were occupationally exposed to airborne radioactive material, which caused an intake of multiple isotopes and an uptake of Co. Committed effective dose equivalents were calculated using ICRP Publication 30 methodology in accordance with US Regulation 10 CFR 20. Doses were in the range of 0.1-2.63 mSv for all individuals. Continued monitoring via whole body counting continues to detect internal contamination of Co from this event at 321 d post intake.

Pillars of Hospital Preparedness in Radiation Emergency Management

Human beings have always suffered and have incurred irreparable damages from different disasters. The most logical way to deal with disaster is to be comprehensively prepared. In line with this, the readiness of hospitals in the vicinity of nuclear centers is of great importance, as this could lead to reduced injuries and damage. In this study, we aimed to develop a model by which hospitals could effectively react to nuclear incidents. This is a comparative study using library studies, including examining existing patterns, recommended policies and instructions of WHO and IEAE, and articles and documents of selected countries that have models for radiation disaster management. The primary developed model was discussed in expert panels and, ultimately, with some modifications, was finalized. The findings of the research indicated that the most important factors in the success of crisis management are skill in predicting a crisis and having a preparation plan for necessary measures at the time of an incident. Different countries have developed various approaches toward radiation incident management that are mostly focused on human resources, medical equipment, and physical space. The model plan developed here includes a two-part foundation with seven pillars. Intra- and intersectorial arrangements are considered as the foundation, and the pillars are physical structure, medical equipment, human resources, process and instructions, intra- and intrasectorial coordination, information systems, and organizational structure. Having an appropriate model for coping with radiation incidents is pivotal for hospitals active in areas with nuclear centers. Undoubtedly, existence of an effective and comprehensive model could reduce the consequences of radiation crises.

Rapid detection of plutonium contamination with and without uranium contamination in wounds by x-ray fluorescence

In the event of an accident at a nuclear fuel handling facility, the wounds of affected workers may be contaminated with plutonium. The current approach for identifying plutonium contamination is by detecting α-particles in the blood stream. However, the applicability of this approach is impeded due to the α-particles being easily shielded by the bodily fluid components. In this study, we investigate a contamination testing method for such cases that involves the collection of blood with a small piece of filter paper, sealing the sample with thin films, and performing x-ray fluorescence analysis. Our previous study on collecting uranium-contaminated blood with filter paper and performing x-ray fluorescence analysis revealed that the effects arising from blood components could be completely removed by peak fitting, and thus water instead of blood was used as a solvent here. Samples containing various amounts of plutonium as well as samples with 150 Bq of plutonium and uranium were prepared with a mass ratio of 0 to 500 times greater than that of plutonium. x-ray fluorescence measurements showed a high linearity and reproducibility of the Pu Lα peak intensity and plutonium radioactivity, and it was clarified that the signal intensity of the Pu Lα peak did not depend on the amount of coexisting uranium. This method will allow for the simple and rapid assessment of plutonium contamination in wounds.

Operational intervention levels for enabling the transition from an emergency exposure situation to an existing exposure situation following a radiological emergency involving release of radioactive material in the environment

Experience has demonstrated lack of preparedness at national levels to manage the consequences of a nuclear or radiological emergency in its later phase which, on occasions, resulted in unjustified actions. To assist Member States preparing for this phase, the International Atomic Energy Agency (IAEA) published guidance (IAEA Safety Standards Series No. GSG-11) recommending, inter alia, for operational intervention levels (OIL_T) to be developed for enabling the transition from an emergency exposure situation to an existing exposure situation. OIL_T are intended to also support decisions be made on lifting or adapting public protective actions imposed early in the emergency response and on actions to be taken to further reduce exposures. Using the methodology provided therein, OIL_T have been calculated for radiological emergencies involving release of the most commonly used alpha, beta and gamma emitting radionuclides in the environment. In addition, an approach for deriving a default OIL_T value has been presented and a default OIL_T value for the ambient dose equivalent rate at 1 m above ground level has been derived. The derived OIL_T values support the application of relevant IAEA safety standards (i.e. No. GSR Part 7 and No. GSG-11) as well as relevant recommendations of the Council Directive 2013/59 in relation to the transition from the emergency exposure situation to an existing exposure situation at national levels. However, they need to be integrated within the national protection strategies to guide the implementation of activities and actions that support the resumption of normal social and economic activity after the emergency which include those concerning return of members of the public, who were resettled during the implementation of evacuation or relocation, to their homes.

Source estimation of an unexpected release of Ruthenium-106 in 2017 using an inverse modelling approach

For the first time since the Chernobyl accident, detectable concentrations of ruthenium-106 were measured across Europe in September and October 2017. The source of this radioactive cloud remains unconfirmed. In this paper we present a forensic inverse modelling study to simultaneously estimate the source location, timing and magnitude of the unexpected ruthenium-106 release using 473 measurements of atmospheric concentration. To do this, we introduce a novel method, which estimates the uncertainty in the often unknown transport error using a Markov chain Monte Carlo approach. We corroborate the conclusions of other studies which suggest the source location is in the Southern Ural region of Russia, where the Mayak nuclear complex is located. Assuming that the Mayak nuclear complex is the most plausible release location, the method estimates that 441±13 TBq was released 12:00-18:00 UTC 24 September 2017, assuming a six hour release window.

Global and regional probabilities of major nuclear reactor accidents

The continued and extended use of nuclear power is often considered and discussed as a viable energy policy option to meet energy demands while also meeting national CO₂ emission reduction goals. A central issue in energy policy for sustainability is the question of nuclear reactor safety. However, studies on nuclear reactor safety often run up against the problem of estimating the probability of a major accident from patchy and limited empirical data. Here, we describe a simple probabilistic model of catastrophic nuclear reactor accidents based on a set of four assumptions. The model treats the accident probability in each of n reactors as a variable and returns the probability of a major accident in the reactor fleet. We find that, at 99.5% reactor safety, the probability of another Chernobyl- or Fukushima-sized event is 49% for the global fleet, and that safety would have to be 99.96% in order to bring that probability below 5%. We discuss our findings in light of the debate on energy policy for sustainability.

A faster and easier biodosimetry method based on calyculin A-induced premature chromosome condensation (PCC) by scoring excess objects

Dicentric analysis and the ring PCC assay as established biodosimetry methods both have limitations in the estimation of absorbed doses in suspected overexposure cases between 5 and 10 Gy. The proposed method based on calyculin A-induced PCC overcomes these limitations by scoring excess objects as the endpoint. This new scoring method can potentially serve as a faster and up-scalable approach that complements the existing methods with higher accuracy at different dose ranges. It can also potentially be performed by less skilled workers when no automated system is available in mass casualty emergency cases to assist with the triage of patients. Additionally, it offers the possibility to further reduce the sample size and PCC induction time. In this pilot study, a calibration curve for excess objects was constructed using the new scoring method for the first time and a blind validation test composed of three unknown doses was carried out. Almost all the dose estimates were within the 95% confidence limits of the actual test doses by scoring only 50-100 PCC spreads. This method was found to be more accurate than ring PCC for doses below 10 Gy.

Use of commercial pharmaceutical drug (Daktarin®) for retrospective/accidental/forensic thermoluminescence dosimetry

Retrospective/accidental dosimetry seeks for materials that can be used as probes for the dose assessment by means of several methods when there is no dose data available (e.g. from personal dosimeters). In the same respect, researchers also seek materials appropriate for forensic purposes, which would allow to identify the prior presence of radioactive materials at buildings, sites or even vehicles. To this direction, several solid-state drugs, which are ubiquitous, have also been studied as probes for the dose estimation in emergency situations. However, due to their heat-sensitive character, measurements were possible only with OSL. The scope of the present work is to identify a heat-resistant drug (Daktarin) and conduct, for the first time, a detailed study of the thermoluminescence properties of it along with computerized curve deconvolution analysis which would shed light on the traps involved. Results indicate that the glow curve of Daktarin has at least three peaks that can be used for dosimetric purposes, since they exhibit linear dose response for doses up to 20 Gy, do not exhibit any sensitization, have high lifetime and their stability with time is good, since an appreciable signal remains unaffected even 3 months post irradiation. All the above were validated conducting dose recovery tests and successfully calculating the unknown delivered dose for various periods after the irradiation of the samples. The new findings are very supportive and point towards the efficient use of commercial pharmaceuticals as probes for retrospective/accidental/forensic dosimetry using thermoluminescence.

Justification and optimization of radiation exposures: a new framework to aggregate arbitrary detriments and benefits

Myriad radiation effects, including benefits and detriments, complicate justifying and optimizing radiation exposures. The purpose of this study was to develop a comprehensive conceptual framework and corresponding quantitative methods to aggregate the detriments and benefits of radiation exposures to individuals, groups, and populations. In this study, concepts from the ICRP for low dose were integrated with clinical techniques focused on high dose to develop a comprehensive figure of merit (FOM) that takes into account arbitrary host- and exposure-related factors, endpoints, and time points. The study built on existing methods with three new capabilities: application to individuals, groups, and populations; extension to arbitrary numbers and types of endpoints; and inclusion of limitation, where relevant. The FOM was applied to three illustrative exposure situations: emergency response, diagnostic imaging, and cancer radiotherapy, to evaluate its utility in diverse settings. The example application to radiation protection revealed the FOM's utility in optimizing the benefits and risks to a population while keeping individual exposures below applicable regulatory limits. Examples in diagnostic imaging and cancer radiotherapy demonstrated the FOM's utility for guiding population- and patient-specific decisions in medical applications. The major finding of this work is that it is possible to quantitatively combine the benefits and detriments of any radiation exposure situation involving an individual or population to perform cost-effectiveness analyses using the ICRP key principles of radiation protection. This FOM fills a chronic gap in the application of radiation-protection theory, i.e., limitations of generalized frameworks to algorithmically justify and optimize radiation exposures. This new framework potentially enhances objective optimization and justification, especially in complex exposure situations.

Estimation of External Contamination and Exposure Rates Due to Fission Product Release

In the event of a radiological incident, the release of fission products into the surrounding environment and the ensuing external contamination present a challenge for triage assessment by emergency response personnel. Reference exposure rate and skin dose rate calibration data for emergency response personnel are currently lacking for cases where receptors are externally contaminated with fission products. Simulations were conducted to compute reference exposure rate coefficients and skin dose rate coefficients from photon-emitting fission products of radiological concern. To accomplish this task, simplified mathematical skin phantoms were created using surface area and height specifications from International Commission on Radiological Protection Publication 89. Simulations were conducted using Monte Carlo radiation transport code using newborn, 1-y-old, 5-y-old, 10-y-old, 15-y-old, and adult phantoms for 22 photon-emitting radionuclides. Exposure rate coefficient data were employed in a case study simulating the radionuclide inventory for a 17 × 17 Westinghouse pressurized water reactor, following three burn-up cycles at 14,600 MWd per metric ton of uranium. The decay times following the final cycle represent the relative activity fractions over a period of 0.5-30 d. The resulting data can be used as calibration standards for triage efforts in emergency response protocols.

A New Smartphone Application to Predict Hematologic Acute Radiation Syndrome Based on Blood Cell Count Changes-The H-module App

Treatment regimens for acute radiation syndrome have been improved over the past years. The application of appropriate therapy relies on rapid and high-throughput tests ideally conducted in the first 3 d after a radiation exposure event. We have examined the utility of blood cell counts (BCCs) 3 d post irradiation to predict clinical outcome for hematologic acute radiation syndrome (HARS). The BCCs and HARS severity information originated from data available in the System-for-Evaluation-and-Archiving-of-Radiation Accidents-based-on-Case-Histories (SEARCH). We found an almost complete discrimination of unexposed (HARS score H0) vs. irradiated individuals during model development and validation (negative predictive value > 94%) when using BCC data for all 3 d. We also found that BCC data increased the correct prediction of exposed individuals from day 1 to day 3. We developed spreadsheets to calculate the likelihood of correct diagnoses of the worried-well, requirement of hospitalization (HARS 2-4), or development of severe hematopoietic syndrome (HARS 3-4). In two table-top exercises, we found the spreadsheets were confusing and cumbersome, so we converted the spreadsheets into a smartphone application, named the H-module App, designed for ease of use, wider dissemination, and accommodation of co-morbidities in the HARS severity prediction algorithm.

Radiation Exposure Biomarkers in the Practice of Medical Radiology: Cooperative Research and the Role of the International Atomic Energy Agency (IAEA) Biodosimetry/Radiobiology Laboratory

The strategy toward personalized medicine in radiation oncology, nuclear medicine, and diagnostic and interventional radiology demands a specific set of assays for individualized estimation of radiation load for safety concerns and prognosis of normal tissue reactions caused by ionizing radiation. Apparently, it seems reasonable to use validated radiation dosimetric biomarkers for these purposes. However, a number of gaps in knowledge and methodological limitations still have to be resolved until dosimetric biomarkers will start to play a valuable role in clinical practice beyond radiation protection and radiation medicine. An extensive international multicenter research is necessary to improve the methodology of clinical applications of biodosimetry. That became a rationale for launching the IAEA Coordinated Research Project E35010 MEDBIODOSE: "Applications of Biological Dosimetry Methods in Radiation Oncology, Nuclear Medicine, and Diagnostic and Interventional Radiology." At the 2 Coordination Meeting on MEDBIODOSE (18-22 February 2019, Recife, Brazil), participants reported progress in the usage of biological dosimetry for genotoxicity assessment and/or individualization of radiotherapy treatment plans. Another avenue of research was the prognosis of normal tissue toxicity and cancer risk prediction using biomarkers' yield measured in vivo or after ex vivo irradiation of patients' cells. Other important areas are mechanisms of cytogenetic radiation response, validation of new radiation biomarkers, development of innovative techniques, automated and high-throughput assays for biodosimetry, and the overall improvement of biodosimetry service. An important aspect of clinical application of biodosimetry is standardization of techniques and unification of approaches to data interpretation. The new IAEA Biodosimetry/Radiobiology Laboratory, which is being established, will provide support for this activity. The declared lab's mission includes, among other tasks, a harmonization of the biodosimetry applications with relevant international standards, guidelines on good laboratory practice, and the IAEA EPR-Biodosimetry manual.

Evaluation of ionizing radiation as a risk factor for the incidence of breast cancer: long-term analysis after the cesium-137 accident in Goiânia, Brazil. An ecological study

BACKGROUND

The largest radiological accident to occur in any urban area happened in Goiânia, Brazil, in 1987.

OBJECTIVE

To evaluate the association between breast cancer incidence and ionizing radiation levels.

DESIGN AND SETTING

Ecological study among residents of the city of Goiânia, Brazil.

METHODS

The central region of Goiânia, with seven major sources of contamination from cesium-137, was defined as the study area. The addresses of women diagnosed with breast cancer were identified between 2001 and 2010. The data were geographically referenced and, using census data, the annual averages of crude incidence rates were estimated. The existence of clusters of new cases was ascertained by means of the Moran index. Correlations of radiometric measurements with the incidence were assessed using unconditional linear regression.

RESULTS

A total of 4,105 new cases were identified, of which 2,233 were in the study area, and of these, 1,286 (57.59%) were georeferenced. The gross rates of total and referenced cases were 102.91 and 71.86/100,000 women, respectively. These were close to the average for Brazilian state capitals, which is 79.37/100,000 women. The cluster analysis showed slight correlations in three small sets of census tracts, but these were far from the sources of contamination. The scatter plot of points and the R2 value close to zero indicated that there was no association between the variables.

CONCLUSION

This study reinforces the hypothesis that the ionizing radiation levels to which women living in Goiânia are now exposed to are not associated with the onset of new cases of breast cancer.

The radiological environment at the Mayak PA site and radiation doses to individuals involved in emergency and remediation operations after the 'Kyshtym Accident' in 1957

This article assesses the radiological environment at the nuclear site of the Mayak PA, Russian Federation, during and after the accident in 1957, the so-called 'Kyshtym Accident', and the radiation doses to those who participated in the eradication of its consequences. Based on numerous archival documents, this paper presents the radiation data for 1957-1960, including individual dosimetry monitoring data and estimated doses to the Mayak workers, as well as the to personnel in supporting organisations and the military involved in the remediation operations. From 1957-1959 some 38 500 individuals took part in the clean-up actions and remediation of contaminated areas of the Mayak PA industrial site after the accident, including individuals exposed at the time of the accident: Mayak PA employees, militarypersonnel, and civil construction workers. External equivalent doses to 10 500 individuals were estimated in the range of 220 to 265 mSv, while there were cases of doses up to 950 mSv and higher. The collective dose received during the accident and its aftermath was in the region of 7300 person-Sv. By October-December 1957, the collective dose was about 4500 person-Sv. Collective doses recorded in 1958 and 1959 amounted to 2250 person-Sv and 480 person-Sv, respectively.

Nuclear power plant: state of knowledge of the population living in the area of the Cattenom special intervention plan. A cross-sectional study

In France information campaigns are periodically conducted within a 10 km radius of nuclear power plants on the protective actions to be adopted in the event of a nuclear accident. The aim of this study was to assess the knowledge of the inhabitants of the Cattenom PPI area on the recommended actions to be adopted in the event of a nuclear accident after the information campaign that took place from 2016 to 2017 and compare its results with a similar study carried out before the information campaign. We performed a cross-sectional study in the Cattenom PPI area after the 2016-2017 information campaign. We administered questionnaires in ten municipalities selected by lot. These questionnaires contained queries on the general protective actions and required approach to taking potassium iodide (KI). The results obtained were compared with the results of a study conducted before the information campaign in the same area. Out of 200 questionnaires administered, 122 people responded. Only 40% of respondents remembered the information campaign. Only 16% knew all of the recommended protective actions. 78% of households had KI and only 60% knew the objective of KI intake. Compared to the results of the study before the information campaign, KI coverage was better (69% versus 78%, p = 0.02) and the dosage was better known (16% versus 28%, p = 0.0003). This study provides an overview of the effectiveness of information campaigns on the procedure in the event of a nuclear accident. This study highlights the insufficient knowledge of people living in the Cattenom PPI area.

How Precision Medicine Might Better Serve Downwinders

Despite the advances in developing nuclear weapons and other technologies, not much is known about the long-term effects of radiation on human health. In a world where nuclear energy could help curb carbon emissions, it almost seems paradoxical that its possible long-term risks and impacts to human health are still poorly understood. While researchers have investigated the effects of acute radiation in the aftermath of nuclear incidents such as Chernobyl, Hiroshima, Nagasaki, and Fukushima, more needs to be done to understand the impacts of long-term and low-dose nuclear radiation. Studying the downwinders from the Nevada Test Site could offer one window to investigate those myriad effects.

Solid cancer risk dependence on the Pasquill-Gifford atmospheric stability classes in a radiological event

In a radiological event, the lack of preliminary information about the site of explosion and the difficulty in predicting the accurate path and distribution of radioactive plumes makes it difficult to predict expected health effects of exposed individuals. So far, in such a health evaluation, radiation-induced stochastic health effects such as cancer are not included. The Pasquill-Gifford atmospheric classes generally allow connecting atmospheric stability with dispersion of radioactive contaminants to the environment. In this work, an environmental release of radioactive Cs-137 was simulated and the resulting relative risk for solid cancer incidence among the affected population calculated. The HotSpot health physics code was used to simulate the radioactive atmospheric dispersion and calculate the Total Effective Dose Equivalent (TEDE), which was then used to estimate the relative risk of cancer incidence. The main results from this work suggest that the relative cancer risk and atmospheric stability classes are linked by differences in the TEDE. Such a finding may support triage, because it adds additional information on the potentially affected population at the early stages of an emergency response.

Dispersion and ground deposition of radioactive material according to airflow patterns for enhancing the preparedness to N/R emergencies

The intent of minimizing the impact of the large amount of radioactive material potentially released into the atmosphere in a nuclear event implies preparedness activities. In the early phase and in absence of field observations, countermeasures would largely rely on a previous characterization of the transport and dispersion of radioactive particles and the potential levels of radioactive contamination. This study presents a methodology to estimate the atmospheric transport, dispersion and ground deposition patterns of radioactive particles. The methodology starts identifying the main airflow directions by means of the air mass trajectories calculated by the HYSPLIT model, and, secondly, the dispersion and the ground deposition characteristics associated with each airflow pattern by running the RIMPUFF atmospheric dispersion model. From the basis of these results, different products can be obtained, such as the most probable transport direction, spatial probability distribution of deposition and the geographical probability distribution of deposition above certain predefined threshold. The method is trained on the HYSPLIT trajectories and RIMPUFF simulations during five consecutive years (2012-2016) at the Almaraz Nuclear Power Plant, in Spain. 3644 forward air mass trajectories were calculated (at 00 and 12 UTC, and with duration of 36 h). Eight airflow patterns were identified, and within each pattern, the persistent days, i.e. those days in which trajectories at 00 and 12 UTC grouped into the same airflow pattern, were extracted to simulate the atmospheric dispersion and ground deposition following a hypothetical ISLOCA accident sequence of 35 h. In total, 833 simulations were carried out, in which ground contamination was estimated at cell level on a non-homogeneous geographical grid spacing up to 800 km from Almaraz. The corresponding outcomes show a large variability in the area covered and in deposition values between airflow patterns, which provide comprehensive and oriented information and resources to decision makers to emergency management.

Using a chain of models to predict health and environmental impacts in Norway from a hypothetical nuclear accident at the Sellafield site

When a nuclear accident occurs, decision makers in the affected country/countries would need to act promptly to protect people, the environment and societal interests from harmful impacts of radioactive fallout. The decisions are usually based on a combination of model prognoses, measurements, and expert judgements within in an emergency decision support system (DSS). Large scale nuclear accidents would need predictive models for the atmospheric, terrestrial, freshwater, and marine ecosystems, for the connections between these in terms of radionuclide fluxes, and for the various exposure pathways to both humans and biota. Our study showed that eight different models and DSS modules could be linked to assess the total human and environmental consequences in Norway from a hypothetical nuclear accident, here chosen to be the Sellafield nuclear reprocessing plant. Activity concentrations and dose rates from ¹³⁷Cs for both humans and the environment via various exposure routes were successfully modelled. The study showed that a release of 1% of the total inventory of ¹³⁷Cs in the Highly Active Liquor Tanks at Sellafield Ltd is predicted to severely impact humans and the environment in Norway if strong winds are blowing towards the country at the time of an accidental atmospheric release. Furthermore, since the models did not have built-in uncertainty ranges when this Sellafield study was performed, investigations were conducted to identify the key factors contributing to uncertainty in various models and prioritise the ones to focus on in future research.