1.1 BACKGROUND
The concept of sustainable development was originally introduced in the 1980s. It defines sustainable development as development that meets the needs of the present without compromising the ability of future generations to meet their own needs. This concept embraces all environmentally sensitive areas of human activities including different types of energy production. In the area of nuclear energy, the focus of sustainable development is on solving key institutional and technological issues including nuclear accident risks, health and environment risks, proliferation risks, economic competitiveness, radioactive waste disposal, sufficiency of institutions and public acceptability. Sustainable development implies demonstration of progress on the key institutional and technological issues. The INPRO methodology is the tool for assessing the sustainability and sustainable development of a nuclear energy system (NES), that was originally created in 2003 under the aegis of the IAEA using broad philosophical outlines of the concept of sustainable development. The latest full version of the INPRO methodology was published in 2008 [1]. The INPRO methodology update project was commenced in 2012 and four updated manuals [2–5] have been published in 2014-2016.
Sustainability issues related to potential exposure in the case of accidents with external release of radiation are discussed in the INPRO methodology area of reactor safety. The INPRO area of reactor safety evaluates enhancements in safety of new nuclear power plant (NPP) designs for the purpose of sustainability assessment but does not evaluate compliance with national or international safety standards. INPRO criteria related to the potential severe accidents, imply reduced frequency of accidents with a major release of radioactivity into the containment due to severe core damage, sufficient natural and engineered processes to control the system, and adequate on-site accident management measures to prevent major radioactive releases into the environment. It is also assumed that in new NPPs the calculated frequency of accidental release of radioactivity into the environment is reduced and the source term of accidental release is so low that calculated consequences would not require public evacuation.
In 2012 the IAEA conceived the project on Environmental Impact of Potential Accidental Releases from Nuclear Energy Systems (ENV-PE) to study different approaches used in the Member States for evaluation of potential accidental releases from nuclear reactors. Eleven institutions from the IAEA Member States took part in the project: the National Atomic Energy Commission, CNEA (Argentina), Republican Scientific-Practical Centre of Hygiene (Belarus), the French Alternative Energies and Atomic Energy Commission, CEA (France), the Karlsruhe Institute of Technology, KIT (Germany), the Indira Gandhi Centre for Atomic Research, IGCAR (India), the National Nuclear Energy Agency, BATAN (Indonesia), the Israel Atomic Energy Commission (Israel), the Russian Institute of Agricultural Radiology and AgroEcology, RIARAE (the Russian Federation), the Centre for Energy, Environment and Technology, CIEMAT (Spain), the Radiation Protection Institute (Ukraine) and Amec Foster Wheeler (the United Kingdom).
This publication is the final report of the ENV-PE summarising results developed under this project by the groups of national experts.
1.2 OBJECTIVE
This publication presents a set of examples of different approaches for estimating potential exposures in different countries based on participants’ experience and considering the IAEA Safety Standard [6] on a generic framework for consideration of radiological environmental
impact, including potential exposures. It is further intended to provide necessary input for the development of common understanding in assessing the population health risks from potential accident scenarios in a nuclear power plant.
This publication will contribute to further improvement and update of the INPRO methodology for sustainability assessment of nuclear energy systems and can help Member States applying the INPRO methodology to perform a nuclear energy system assessment in the areas of safety and environment.
This publication is intended for use by organizations involved in development and deployment of NESs including planning, design, modification, technical support and operation for nuclear power plants.
1.3 SCOPE
This publication is focused on the estimation of off-site consequences of a severe accident in an NPP resulting in major release of radioactivity to the environment. Assessment of potential exposures was performed by national experts based on their experience, and considering the general framework published in the IAEA Safety Standards [6]. The outcome of independent dose and risk assessments from potential radioactive release to the environment is presented here along with the summary of discussion on the following topics:
- Accident source term definition;
- Exposure scenarios and environmental dispersion models (atmospheric) applicable to accidental releases;
- Representative persons for assessing doses (location, characteristic, habits, age groups);
- Dose assessment (pathways, radionuclides, short term and long-term doses);
- Consideration of levels adopted for protective measures.
A single scenario of release from the postulated accident was evaluated by the participants:
release into the atmosphere from a severe accident in an NPP. Potential liquid releases into the sea or rivers are not considered. A potential accident scenario was defined as a postulated source term, the associated probability and representative environmental data. Potential exposures are considered through the estimation of radiation doses and in some cases through the associated risk to human health caused by the radioactive release. In a few cases there were existing national regulations which defined or provided elements for the consideration of potential exposures. Calculation of the need for and effect of response actions as part of emergency preparedness as well as evaluation of economic losses have not been considered in this project.
Protection of the environment includes the protection of living organisms other than humans and also the protection of natural resources, including land, forests, water and raw materials, together with a consideration of non-radiological environmental impacts from the NPP.
However, this study is mostly concerned only with the radiological impact on humans as the target group. An example of radiological impact on non-human biota was considered in one national study for completeness. The explicit consideration of effects to non-human biota (currently from normal operation only) is a recent development in the field of radiation protection [7-9] and is being considered and incorporated in the IAEA Safety Standards [6, 10-12] and in some national regulations.
The methods and criteria presented in this report do not represent the national practices required in the regulations and should be considered as a proposal by the experts for possible approaches to estimate potential exposures.
1.4 STRUCTURE
Following this introduction, Section 2 describes general considerations of assessing potential public exposure in nuclear accidents. Information on the input data used, together with the influencing parameters and how they were applied, is given in Section 3. In Section 4, a comparison of models and approaches used in national case studies is provided. Section 5 presents a summary of the results obtained by the national experts. Annexes I to X comprise national studies including:
- Elements for consideration of potential exposures applied in different countries, including dose/risk and protective actions criteria,
- Description of methodologies used by national experts, - Results of calculations.
2 GENERAL CONSIDERATIONS OF ASSESSING POTENTIAL PUBLIC