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[en] The STRATEGY project (Sustainable Restoration and Long-Term Management of Contaminated Rural, Urban and Industrial Ecosystems) aimed to provide a holistic decision framework for the selection of optimal restoration strategies for the long-term sustainable management of contaminated areas in Western Europe. A critical evaluation was carried out of countermeasures and waste disposal options, from which compendia of state-of-the-art restoration methods were compiled. A decision support system capable of optimising spatially varying restoration strategies, that considered the level of averted dose, costs (including those of waste disposal) and environmental side effects was developed. Appropriate methods of estimating indirect costs associated with side effects and of communicating with stakeholders were identified. The importance of stakeholder consultation at a local level and of ensuring that any response is site and scenario specific were emphasised. A value matrix approach was suggested as a method of addressing social and ethical issues within the decision-making process, and was designed to be compatible with both the countermeasure compendia and the decision support system. The applicability and usefulness of STRATEGY outputs for food production systems in the medium to long term is assessed
[en] Over recent years, a number of approaches have been developed that enable the calculation of dose rates to animals and plants following the release of radioactivity to the environment. These approaches can be used to assess the potential impacts of activities that may release radioactivity to the environment, such as the operation of waste repositories. A number of national and international studies have identified screening criteria to indicate those assessment results below which further consideration is not generally required. However no internationally agreed criteria are currently available and consistency in criteria between countries has not been achieved. Furthermore, since screening criteria are not intended to be applied as limits, it is clear that they cannot always form a sufficient basis for assessing the adequacy of protection afforded. Typically, exceeding a screening value leads to a regulatory requirement to undertake a further, more detailed assessment. It does not, per se, imply that there is inadequate protection of the organism types at the specific site under assessment. Therefore, there is a need to develop a more structured approach to dealing with situations in which current screening criteria are exceeded. As a contribution to the developing international discussions, and as an interim measure for application where assessments are required currently, a two-tier, three zone framework is proposed here, relevant to the long term assessment of potential impacts from the deep disposal of radioactive wastes. The purpose of the proposed framework is to promote a proportionate and risk-based approach to the level of effort required in undertaking and interpreting an assessment. - Highlights: • A two-tier framework is proposed, relevant to disposal of radioactive wastes. • The framework may help structure dialogue between regulators and industry. • Tier 1 represents a generic screening value, which could be set at 10 μGy/h. • Tier 2 represents ‘limited effects’ and may be set to a generic 100 μGy/h. • Above Tier 2 there is an increasing emphasis on justification
[en] Highlights: • Geochemical modeling, and particularly chemical thermodynamics, is particularly important in performance assessment. • The NEA TDB Project provides a database of high quality, used extensively worldwide. • Several national nuclear programs have drawn heavily on the NEA TDB as a basis upon which they built their own datasets. • The NEA TDB could be envisioned as an approach that could potentially be used in broader areas of environmental interest, nuclear and beyond. - Abstract: For the last 30 years, the NEA Thermochemical Database (TDB) Project (www.oecd-nea.org/dbtdb/) has been developing a chemical thermodynamic database for elements relevant to the safety of radioactive waste repositories, providing data that are vital to support the geochemical modeling of such systems. The recommended data are selected on the basis of strict review procedures and are characterized by their consistency. The results of these efforts are freely available, and have become an international point of reference in the field. As a result, a number of important national initiatives with regard to waste management programs have used the NEA TDB as their basis, both in terms of recommended data and guidelines. In this article we describe the fundamentals and achievements of the project together with the characteristics of some databases developed in national nuclear waste disposal programs that have been influenced by the NEA TDB. We also give some insights on how this work could be seen as an approach to be used in broader areas of environmental interest.
[en] The setting up of the Greek Stakeholders Group in the framework of the EC Food and Agriculture Restoration Management Involving Networked Groups (FARMING) project is described. The Group included members from more than 20 governmental and non-governmental organisations, having interest and/or responsibilities in the management of a crisis following a nuclear accident. The stakeholders, during their meetings in 2002, discussed the agricultural countermeasures and rural waste disposal options which have been compiled by the EC Sustainable Restoration and Long-Term Management of Contaminated Rural, Urban and Industrial Ecosystems (STRATEGY) project. All stakeholders agreed that the most preferable were those options that ensure public acceptance, minimise environmental impact and maintain farming practices and acceptable living and working conditions. Their views are synoptically presented along with the major conclusions from the stakeholders meetings regarding nuclear crisis management
[en] The 2007 Recommendations of the International Commission on Radiological Protection (ICRP) represent a change from a process-based to an exposure-based approach, where exposure situations are categorised as planned, emergency, and existing exposure situations. Although the new Recommendations contain further changes based on, inter alia, scientific developments since the publication of the 1990 Recommendations, they overall represent more continuity than change - a notable exception being the direct consideration of environmental protection. The implications of the new Recommendations for radioactive waste management are fairly marginal, as earlier recommendations in this area are still considered valid. This communication provides a brief overview of the current ICRP system for radiological protection as applied to radioactive waste management, as well as an outlook including the possibility of using the developing ICRP system for management of environmental effects as an 'alternative way of reasoning' when building the safety case for a specific waste disposal concept.
[en] When assessing the radiological impacts of radioactive waste disposal, irrigation using groundwater contaminated with releases from the disposal system is a principal means of crop and soil contamination. In spite of their importance for radiological impact assessments, irrigation data are scarce and often associated with considerable uncertainty for several reasons including limited obligation to measure groundwater abstraction and differences in measuring methodologies. Further uncertainty arises from environmental (e.g. climate and landscape) change likely to occur during the assessment long time frame. In this paper, we derive irrigation data using the crop growth AquaCrop model relevant to a range of climates, soils and crops for use in radiological impact assessments. The AquaCrop estimates were compared with actual irrigation data reported in the literature and with estimates obtained from simple empirical methods proposed for use in radiological impact assessments. Further, the AquaCrop irrigation data were analysed using mixed effects modelling to investigate the effects of climate, soil and crop type on the irrigation requirement. Irrigation estimates from all models were within a reasonable range of the measured values. The AquaCrop estimates, however, were at the higher end of the range and higher than those from the empirical methods. Nevertheless, they may be more appropriate for conservative radiological assessments. The use of mixed effects modelling allowed for the characterisation of crop-specific variability in the irrigation data, and in contrast to the empirical methods, the AquaCrop and the mixed effects models accounted for the soil effect on the irrigation requirement. The approach presented in this paper is relevant for obtaining irrigation data for a specific site under different climatic conditions as well as for generic dose assessments. To the best of our knowledge, this is one of the most comprehensive analyses of irrigation data in the context of radiological impact assessment currently available. - Highlights: • Generic irrigation data for radiological assessments are scarce • We derive irrigation data using multi-crop and empirical models • All derived values were within reasonable range of measured data • The values from the multi-crop are more suitable for conservative assessments
[en] Depending on the particular circumstances in which a post-closure performance assessment of a radioactive waste repository is made, it may be appropriate to follow simple or more complex approaches in characterising the biosphere. Several different Example Reference Biospheres were explored in BIOMASS Theme 1 to address a range of issues that arise. Here, consideration is given to Example Reference Biospheres relevant to representing the implications of changes that may occur within the biosphere system during the period over which releases of radionuclides from a disposal facility might take place. Mechanisms of change considered include those extrinsic and intrinsic to the system of interest. An overall methodology for incorporating environmental change into assessments is proposed. This includes screening of primary mechanisms of change; identification of possible time sequences of change; development of a coherent description of the regional landscape response for each time sequence; integration of source term and geosphere-biosphere interface information; identification and description of one or more time series of assessment biospheres; and evaluation of the advantages and disadvantages of simulating the effects of sequences of biosphere systems and the transitions between them, or of defining a set of biosphere systems to be represented individually in a non-sequential analysis. The usefulness of the methodology is explored in two site-specific examples and one generic example
[en] Decisions on permitting, controlling and monitoring releases of radioactivity into the environment rely on a great variety of factors. Important among these is the prospective assessment of radionuclide behavior in the environment, including migration and accumulation among and within specific environmental media, and the resulting environmental and human health impacts. Models and techniques to undertake such assessments have been developed over several decades based on knowledge of the ecosystems involved, as well as monitoring of previous radionuclide releases to the environment, laboratory experiments and other related research. This paper presents developments in the assessment of radiation doses and related research for some of the key radionuclides identified as of potential significance in the context of releases to the biosphere from disposal facilities for solid radioactive waste. Since releases to the biosphere from disposal facilities involve transfers from the geosphere to the biosphere, an important aspect is the combined effects of surface hydrology, near-surface hydrogeology and chemical gradients on speciation and radionuclide mobility in the zone in which the geosphere and biosphere overlap (herein described as the geosphere-biosphere subsystem). In turn, these aspects of the environment can be modified as a result of environmental change over the thousands of years that have to be considered in radioactive waste disposal safety assessments. Building on the experience from improved understanding of the behavior of the key radionuclides, this paper proceeds to describe development of a generic methodology for representing the processes and environmental changes that are characteristic of the interface between the geosphere and the biosphere. The information that is provided and the methodology that is described are based on international collaborative work implemented through the BIOPROTA forum, (www.bioprota.org). - Highlights: • Geological disposal of radioactive waste and release of radionuclides to the biosphere. • Processes for transfer across the geosphere-biosphere interface (GBI). • Near-surface hydrogeology and chemical gradient effects on transfer across the GBI. • Near-surface system evolution due to climate and other environmental change. • Generic methodology for representing radionuclide transfer across the GBI
[en] Demonstrating competence in planning and executing the disposal of radioactive wastes is a key factor in the public perception of the nuclear power industry and must be demonstrated when making the case for new nuclear build. This work addresses the particular waste stream of irradiated graphite, mostly derived from reactor moderators and amounting to more than 250,000 tonnes world-wide. Use may be made of its unique chemical and physical properties to consider possible processing and disposal options outside the normal simple classifications and repository options for mixed low or intermediate-level wastes. The IAEA has an obvious involvement in radioactive waste disposal and has established a new project ‘GRAPA’ – Irradiated Graphite Processing Approaches – to encourage an international debate and collaborative work aimed at optimising and facilitating the treatment of irradiated graphite. - Highlights: • Irradiated graphite waste management within IAEA GRAPA Project is considered. • Chemical and physical properties are accounted on developing processing methods. • IAEA GRAPA aims to encourage an international debate and collaborative work. • GRAPA aimes at optimising and facilitating the treatment of irradiated graphite.
[en] Quantification of solute transport in natural waters is a key aim, or major component, of many geochemical studies. In models which describe such transport, the interactions of solute with solid phases are usually bulked into a simple distribution coefficient (Kd) term. Recently, there has been an increasing number of papers which purport to measure in-situ Kd values, which may be further claimed to be preferable to conventional laboratory measurements. This paper demonstrates that the general application of such in-situ values to transport modelling may be incorrect - especially in low-flow environments. In particular, for applications in which the movement of contaminants such as toxic wastes is concerned, these in-situ values may be non-conservative in the sense that they underpredict releases. (author)