Emergency Exposure Situations Research Articles

Legal regulation of human protection against the effects of ionizing radiation (implementation of EU standards in the legislation of Ukraine)

The legal regulation of human protection against the effects of ionizing radiation (implementation of EU standards in the legislation of Ukraine) is considered. The legal aspects related to the change of the existing system of radiation protection of a person from the impact of ionizing radiation, which is based on the approach - «practice» and «intervention», to the modern European system of radiation protection, which is based on situational analysis and the key concept of the updated system, have been studied. what is the exposure situation, which is defined as one of three situations: planned situation, emergency exposure situation, existing exposure situation.
 According to the results of the study, the need for a comprehensive approach to the implementation of EU legislation in the legislation of Ukraine «on the example of the Council Directive 2013/59/Euratom» is substantiated. In particular, we believe that it is advisable to do this by one separate law, and not in parts, since without the implementation of the main provisions, the implementation of individual provisions leads to problems with their implementation. In our opinion, the Government of Ukraine should develop an «autonomous road map» for each EU directive, the implementation of which concerns the field of activity of more than one public administration body in the field of nuclear energy use, since some provisions of the Directive are not included in the draft laws on implementation, as they belong to spheres of administration of another state administration body. At the same time, aspects of the extensive legislation regulating relations regarding liquidation of the consequences of the Chernobyl accident should be reflected, in particular in the part of radiation protection, which cannot be reflected in the Directive, but belong to the scope of its regulation. Thus, it will simultaneously allow internal harmonization of legislation and avoid the situation of double interpretation of legislation, will contribute to overcoming contradictions, collisions and gaps in the current legislation of Ukraine.
 In some cases, it is important to carry out the synchronous development of other basic regulatory documents, in particular, new Radiation Safety Norms in order to make a harmonious transition from the existing to a new system of radiation protection of humans against the effects of ionizing radiation. In the future, this will contribute to a more successful systematization and harmonization of the entire array of normative legal acts of nuclear legislation in Ukraine.

Assessment of the environmental radiological impact in the emergency exposure phase through the simulation of a uranium mining tailings dam breach

This work is aiming at estimating the radiation doses to members of the public in case of an emergency exposure situation related to a hypothetical uranium mining tailings dam rupture at the UDC - Decommissioning Unit of Caldas, MG, Brazil. The calculations will help to managing the exposures of emergency workers and residents in the region downstream the dam. The computer code chosen to perform the simulations was FLO-2D@ software. Due to the uncertainties involved, mainly regarding the waste rheology and activity concentrations and in parameters values to be used in the dose assessment, considerations were made for the study to present results derived from conservative assumptions. Through the creation of flood maps, it was possible to estimate the extent of the areas affected by the released materials. The results showed that in a scenario of the tailings dam breach, deposition of mud shall extend over 20 km downstream affecting an area of nearly 3 km2. Total dose for a member of the public living in most affected areas would be around 43 mSv/y in the early phase after the accident. Although only shielding would be recommended under current radiation protection regulation, evacuation/relocation is suggested due to the presence of long-lived radionuclides. This protective measure would probably already be indicated by the accident itself, regardless of radiological reasons. More realistic assessment should be performed before returning people, considering long-term environmental transport and uses of the area. It must also be considered that long-term exposures have more restricted recommended acceptable levels than those for the emergency phase.

Оценка радиационной безопасности населения загрязнённых вследствие аварии на Чернобыльской АЭС районов Брянской области на основе расчёта радиационных рисков с учётом их неопределённостей

The current recommendations of the International Commission on Radiological Protection (ICRP) are based on the classification of exposure situations as: planned, emergency and existing exposure situations. In planned situations, annual risk limits are set to limit human exposure. However, in emergency exposure situations or in existing exposure situations, permanent (annual) source control is not always possible, so the radiation protection strategy by monitoring the individual annual risk limit cannot always be practically implemented either. The purpose of this work is to assess the radiation safety of the population currently residing (at the beginning of 2022) in six districts of the Bryansk region: contaminated with radionuclides as a result of the Chernobyl accident: in Gordeevsky, Zlynkovsky, Klimovsky, Klintsovsky, Krasnogorsky and Novozybkovsky districts. Assessment of the current state of radiation safety of the population is based on calculations of the radiation detriment from chronic exposure due to living in contaminated areas, considering uncertainties of the reconstructed exposure doses and the parameters of mathematical risk models for the population. Radiation damage is calculated according to the modern ICRP methodology. Based on the general principle of conservative assessment of safety, the calculated upper 95% confidence limits (95% CL) of radiation detriment are compared with the corresponding lifetime radiation detriment limit, 3.510-3, determined by the Russian radiation safety standards (NRB-99/2009) under normal exposure conditions for the nominal period 70 years of life for the public. The radiation safety of the population of the Klimovsky district corresponds to the normal conditions of exposure from technogenic sources of ionizing radiation. Among the population of the remaining five contaminated districts of the Bryansk region, critical groups have been identified, the radiation detriment for which exceeds the limit 3.510-3 for normal conditions of public exposure in planned situations. The results of this work can be used in the preparation of recommendations for health authorities to improve medical monitoring of exposed citizens living in territories contaminated with radionuclides, as well as in the development of regulatory documents for the provision of targeted medical care to people from high radiation risk groups with the use of personalized medicine methods.

The application of the optimization principle in the Italian and European context

The transposition of Directive 2013/59/Euratom has projected Italian radiation protection into the new safety culture, in which optimization is a multidisciplinary process pursuing a suitable balance among different risks. The fundamental tools in the application of the optimization principle are source-related dose constraints, introduced by the Directive to define the range of options to be considered. This article analyzes some critical issues in their use when managing radiation protection at work in any planned, existing or emergency exposure situation, which involves a risk from exposure to ionizing radiation. Simplified procedures and customized guidelines are outlined from international organizations, such as IAEA, OECD/NEA, and the European ALARA Network (EAN), paving the way to a correct implementation of the optimization principle.

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 (OILT) to be developed for enabling the transition from an emergency exposure situation to an existing exposure situation. OILT 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, OILT 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 OILT value has been presented and a default OILT value for the ambient dose equivalent rate at 1 m above ground level has been derived. The derived OILT 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.

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.

An experiential approach to developing radiological content for public health nursing: Lessons from a nuclear disaster.

This study identified the radiological content required for PHNs and public health nursing students based on PHNs' experiences caring for people affected by the 2011 Fukushima Daiichi nuclear power plant accident. We used qualitative research, interviews, and content analysis. Participants were eight PHNs employed by local governments in Fukushima and neighboring prefectures. Six content themes regarding the nuclear disaster were identified: (a) basic knowledge about radiation, (b) public health nursing activities in emergency exposure situations, (c) management in emergency exposure situations, (d) consultation to support residents affected by the nuclear disaster, (e) activities in the existing exposure situations, and (f) disaster preparedness in the planned exposure situations. Necessary content shifted depending on the phase of the nuclear disaster recovery. The use of the experiences of PHNs after the nuclear power plant accident to inform PHNs and public health nursing students will enable PHNs to respond appropriately and support people without difficulties. Comprehensive radiation content is needed to address the range of situations caused by nuclear disaster.

Исследование современных моделей радиационных рисков НКДАР ООН, МКРЗ и ВОЗ при их применении для оценки радиационных рисков в ситуациях аварийного облучения

Исследование современных моделей радиационных рисков НКДАР ООН, МКРЗ и ВОЗ при их применении для оценки радиационных рисков в ситуациях аварийного облучения

Numerical Study of Long-Term Radioactivity Impact on Foodstuff for Accidental Release Using Atmospheric Dispersion Model

The radiological consequences of a potential atmospheric release of $$^{131}$$ I, $$^{137}$$ Cs, $$^{133}$$ Xe and $$^{90}$$ Sr for hypothetical accident appropriate to a 10 MW research reactor were calculated. The Gaussian model CROM (Screening Model for Environmental Assessment) was used to compute the accidental radioactive release under emergency exposure situation and the estimation of yearly average dose by different exposure pathways. The realistic assessment of radiation level due to the abnormal occurrence operation of nuclear installations such as foods consumption, external irradiation, inhalation and ingestion has been examined. In this study, the evaluation of the dose results, to a continuous emissions rate under dry and wet deposition process, was estimated onto six reference groups of public covering the period from the new born infant to more than 17 years old as defined by the International Commission on Radiological Protection. The obtained modeling results were compared to the limits values prescribed by IAEA and Euratom recommendations. The findings indicate that the ground concentrations were found to be significant and mostly sensitive to the emission conditions, when the total deposition exceeds the contamination limits. The short-lived isotopes have much more influence on the concentration on foodstuff. The activity concentration of $$^{131}$$ I is significantly higher in animal products and vegetables, while the $$^{137}$$ Cs is dominant in fruits vegetables. In contrast, the Noble gas $$^{133}$$ Xe is significantly lower.

Integration of radiological protection of the environment into the system of radiological protection.

In 2005, the International Commission on Radiological Protection (ICRP) decided to create a new committee, Committee 5, to take charge of the Commission's work on environmental radiological protection. Committee 5 was tasked with ensuring that the system for environmental radiological protection would be reconcilable with that for radiological protection of humans, and with the approaches used for protection of the environment from other potential hazards. The task was completed over three consecutive terms, resulting in inclusion of protection of the environment in the 2007 Recommendations; in ICRP Publications 108 and 114 where the concept of Reference Animals and Plants (RAPs) and their corresponding data were described; in ICRP Publication 124 on how to apply the system in planned, existing, and emergency exposure situations; and in publications on improved dosimetry (ICRP Publication 136) and ecologically relevant 'weighting factors' for different types of radiation (being finalised for public consultation). With the beginning of this new term, ICRP has moved to integrate its approach to protection of humans and the environment within the system of radiological protection by tasking aspects of an integrated system to each of the committees. Acknowledging that Committee 5 had fulfilled its mission, in 2016, ICRP revised the mandates for the committees effective of 1 July 2017 (the mandate for Committee 3 was also widened to include exposures incurred in veterinary practice). ICRP is moving towards the future, building on the previous successes, and will under these revised mandates approach radiological protection in a holistic manner (an integrated system) where appropriate consideration is given to the understanding of exposures and effects in the environment under different exposure situations and scenarios, and what protective actions might be warranted under such circumstances.

The new mandate and work of ICRP Committee 4.

Committee 4 of the International Commission on Radiological Protection (ICRP) is charged with the development of principles and recommendations on radiological protection of people and the environment in all exposure situations. For the term beginning in July 2017, the Committee has a total of 18 members from 12 countries. The programme of work includes a wide range of activities in five major thematic areas. The first is the consolidation and preparation of reports elaborating application of the system of protection in existing exposure situations. Second is the continuation of work on emergency exposure situations, and ICRP updates to recommendations in light of the accident at Fukushima Daiichi nuclear power plant. Third is examination of fundamentals of protection recommendations, including the ethical principles underlying the recommendations and application of those principles in practical decision making. Fourth is the new area of integration of protection of the environment into the system of protection. Finally, Committee 4 continues work to prepare specific topical reports on subjects in which additional information is useful to understand and apply the Commission's recommendations in particular circumstances.

Implementation of the integrated approach in different types of exposure scenarios.

The International Commission on Radiological Protection (ICRP) recognises three types of exposure situations: planned, existing, and emergency. In all three situations, the release of radionuclides into the natural environment leads to exposures of non-human biota, as well as the potential for exposures of the public. This paper describes how the key principles of the ICRP system of radiological protection apply to non-human biota and members of the public in each of these exposure situations. Current work in this area within ICRP Task Group 105 is highlighted. For example, how simplified numeric criteria may be used in planned exposure situations that are protective of both the public and non-human biota. In emergency exposure situations, the initial response will always be focused on human protection; however, understanding the potential impacts of radionuclide releases on non-human biota will likely become important in terms of communication as governments and the public seek to understand the exposures that are occurring. For existing exposure situations, there is a need to better understand the potential impacts of radionuclides on animals and plants, especially when deciding on protective actions. Understanding the comparative impacts from radiological, non-radiological, and physical aspects is often important in managing the remediation of legacy sites. Task Group 105 is making use of case studies of how exposure situations have been managed in the past to provide additional guidance and advice for the protection of non-human biota.

Conclusions and recommendations from the 17th Workshop of the European ALARA Network ‘ALARA in emergency exposure situations’

The European ALARA Network regularly organises workshops on topical issues in radiation protection. In light of the Fukushima accident, the most recent workshop questioned the application of the ALARA principle in emergency exposure situations. This memorandum presents the conclusions and recommendations of this workshop. One of the outcomes is that the process of optimisation in emergency exposure situations should be flexible enough to be able to modify or refine decisions over the course of an accident. In the urgent phase, decisions must be made in a very time-constrained environment, based on scarce, uncertain and sometimes unreliable information. In this phase, optimisation and protection strategies are therefore developed and applied on the basis of conservative assumptions or ‘reasonably foreseeable worst-case scenario’ which could lead to an overestimation of the consequences. In the intermediate phase, knowledge of the situation improves, and more time is available to make the decision. This is reflected by adopting a less conservative approach, and transitioning to a more appropriate optimisation adapted as effectively as possible to the various exposure situations. When the situation is eventually stabilized (transition phase), there is time to shape the measures taken previously to reflect local conditions in the affected territories. In every phase, consideration should be given to the stakeholders, so that their needs and requirements can be incorporated as effectively as possible.

Food Ingestion Standards for Nuclear Emergency Exposure Situations

Food Ingestion Standards for Nuclear Emergency Exposure Situations

Methods of minimising doses incurred by external exposure while moving in radiation hazardous areas

Radiation doses received by workers during their movement within areas contaminated as a result of events and activities, leading to emergency or existing exposure situations, may provide a substantial contribution to total external exposure during remediation work. This paper describes an approach to minimise worker external exposure in these circumstances, based on graph theory. The paper describes several tasks, including: searching for a route with the lowest dose, searching for an optimal bypass with a given set of control points and searching for the optimal road network coverage. Classical graph theory algorithms have been used (Dijkstra’s algorithm, Chinese postman problem and travelling salesman problem). Algorithms for solving the above mentioned problems have been developed and were included in the information-analytical system for radiation safety. This software has been applied for optimisation of protection during remediation work at the Andreeva Bay site of temporary storage for spent fuel and radioactive waste in the Kola Peninsula, both in the context of existing exposure situations and improving the preparedness for emergency exposure situations.

Overview of ICRP Committee 5: protection of the environment.

Protection of the environment is integral to the system of radiological protection, as outlined in the 2007 Recommendations of the International Commission on Radiological Protection (ICRP, Publication 103). The Commission's activities in this area are mainly pursued by Committee 5 and its associated Task Groups. Publication 91 broadly outlines the approach to radiological protection of the environment, and its alignment with approaches to environmental protection from hazardous substances in general. Publications 108 and 114 provide the cornerstones of the environmental protection system and relevant databases. Publication 124 considers its application in planned, existing, and emergency exposure situations. The system centres on 12 Reference Animals and Plants (RAPs) with broad relevance for environmental protection based on their ubiquity and significance as well as other criteria, as described in Publication 108 The databases comprise general biology of the RAPs, transfer parameters, dose conversion coefficients, and effects data. Derived Consideration Reference Levels (DCRLs) were established for each RAP; a DCRL represents a band of dose rates that might result in some deleterious effects in individuals of that type of RAP. Newly established Task Group 99 will compile the RAP-specific reference information into monographs, with the view of updating information and improving the applicability of the system in different exposure situations. For certain scenarios, more precise and ecosystem-specific protection benchmarks may be justified, which would have to be informed by consideration of representative organisms (i.e. representative of a particular ecosystem and relevant to the specific scenario; Publication 124). Committee 5 will explore this further, making use of a limited number of case studies.

Update of ICRP Publications 109 and 111.

The Task Group (TG) of Committee 4 was created to update the International Commission on Radiological Protection (ICRP) Publications 109 and 111 in light of the lessons from Fukushima, recent international developments concerning the protection of people in emergency exposure situations, and people living in long-term contaminated areas after a nuclear accident or a radiation emergency. An important aspect of the TG's approach focuses on clarifying the consequences of the introduction of the situation-based approach to implementation of radiological protection that was introduced in ICRP Publication 103 in place of the previous approach based on the distinction between practices and interventions. The TG focused its reflection on several issues revealed by the Fukushima accident in relation to the justification and optimization of emergency decisions, the characterization of the radiological situation, the protection of emergency and recovery responders, the decontamination and waste management strategies, the management of contaminated foodstuffs and commodities, the shift from the emergency to the existing exposure situation, and the co-expertise process to develop radiological protection culture among the affected population.

Application of the Commission's recommendations: the 2013-2017 Committee 4 programme of work.

Committee 4 of the International Commission on Radiological Protection (ICRP) is responsible for developing principles, recommendations, and guidance on the protection of people against radiation exposure, and to consider their practical application in all exposure situations. Currently, the Committee's efforts are focused on the completion of a series of future ICRP publications on the implementation of its 2007 Recommendations to the various existing exposure situations. A report on protection against radon exposure was published recently (ICRP Publication 126), and two documents on protection against cosmic radiation in aviation, and naturally occurring radioactive material are under development. The programme of work for the forthcoming 2013-2017 period comprises the update of ICRP Publication 109 on protection of people in emergency exposure situations, and the update of ICRP Publication 111 on protection of people living in long-term contaminated areas after a nuclear accident, as well as the development of a future ICRP publication on the ethics of radiological protection. It also includes the preparation of task groups on the application of the Commission's recommendations for contaminated sites from past activities and for surface and near-surface disposal of radioactive waste. Another important task for Committee 4 will be to develop a reflection on the tolerability of risk from radiation.

Review of the ICRP system of protection: the approach to existing exposure situations.

The International Commission on Radiological Protection (ICRP) system of protection consists of existing, planned, and emergency exposure situations. With the 2007 Recommendations in ICRP Publication 103, a coherent approach has been established that emphasises the optimisation of protection with appropriate constraints or reference levels in each exposure situation. Existing exposure situations pose unique challenges because the source of exposure already exists, and it may not always be possible to control the source directly. This is the case for naturally occurring sources, which are ubiquitous in the environment and vary widely in the magnitude of exposures that may be received by individuals. Decisions on protection strategies must consider a graded, pragmatic, and flexible approach for dealing with exposure of members of the public, and those that may be occupationally exposed while working with naturally occurring sources. Although limits are not applicable, aspects of the management approach for planned exposure situations may be appropriate, depending upon the magnitude of exposures.

Emergency exposure situations: An update

International Commission on Radiological Protection (ICRP) publication 103 (2007) provided the basic recommendations on radiological protection to cover all radiation exposure situations. It has provided dose limits, dose constraints, and reference levels for use in such situations. Based on these recommendations, International Atomic Energy Agency (IAEA), in its revised basic safety standards (BSS, 2014), provided generic requirements and guidance levels for use by the operators, radiation protection professionals, and the regulators. However, these are generic in nature, and national regulatory authorities are required to decide on the levels for use in their own emergency preparedness and response plans as appropriate: This article just updates the present scenario for emergency exposure situations. The information/material provided in this paper is extracted from the documents listed in the references. For detailed information required for any medical/legal purposes, the readers are expected to refer to the original documents, ICRP-103 (2007) and IAEA-BSS-2014.