Assessment of the environmental and radiological consequences of a nuclear accident requires the management of a great deal of data and information as well as the use of predictive models. Computerised Decision Support Systems (CDSS) are essential tools for this kind of complex assessment and for assisting experts with a rational decision process. The present work focuses on the assessment of the main features of selected state-of-the-art CDSS for off-site management of freshwater ecosystems contaminated by radionuclides. This study involved both developers and end-users of the assessed CDSS and was based on practical customisation exercises, installation and application of the decision systems. Potential end-users can benefit from the availability of several ready-to-use CDSS that allow one to run different kinds of models aimed at predicting the behaviour of radionuclides in aquatic ecosystems, evaluating doses to humans, assessing the effectiveness of different kinds of environmental management interventions and ranking these interventions, accounting for their social, economic and environmental impacts. As a result of the present assessment, the importance of CDSS "integration" became apparent: in many circumstances, different CDSS can be used as complementary tools for the decision-making process. The results of this assessment can also be useful for the future development and improvement of the CDSS.

The Chernobyl accident led to a long-term crisis that affected agriculture, food and living conditions in complex ways, and that modified the usual economical, political and social relations between public and private stakeholders at local, national and international level. The EC FARMING project aims to create a European stakeholder network to consider possible rehabilitation strategies for rural areas contaminated after a nuclear accident. The Institute of Patrimonial Strategies of the National Institute on Agronomy had responsibility for setting up the French stakeholder group. The objective was to develop favourable conditions and ways whereby stakeholders could deal with such a complex situation as a nuclear emergency and develop rehabilitation strategies. The results from the 3-year work programme on both strategic and technical aspects, showed an increasing commitment from the stakeholders that led to the building up of a common understanding of what a nuclear accident could be and how it could be dealt with.

The evaluation of the rehabilitation strategies implemented in the contaminated territories of the CIS countries affected by the accident at the Chernobyl Nuclear Power Plant highlighted the need and importance to involve the population in the day-to-day management of the radiological situation, to complement the rehabilitation programme implemented by public authorities. The ETHOS experience in Belarus has revealed that to be effective and sustainable, this involvement must rely on the dissemination of a practical radiological protection culture within all sectors of the population and especially within professionals in charge of public health. The objective of the SAGE Project is to contribute to the development of strategies and guidance for implementing and disseminating such a culture in Western Europe, in case of a nuclear incident or accident with long-term radiological consequences. This paper presents the structure of the project, the stakeholder involvement process which has driven its realisation and the handbook on practical radiation protection culture which was elaborated, with different associated computer tools for people living in a contaminated territory.

The present paper summarises the results of the review and assessment of state-of-the-art models developed for predicting the migration of radionuclides through rivers. The different approaches of the models to predict the behaviour of radionuclides in lotic ecosystems are presented and compared. The models were classified and evaluated according to their main methodological approaches. The results of an exercise of model application to specific contamination scenarios aimed at assessing and comparing the model performances were described. A critical evaluation and analysis of the uncertainty of the models was carried out. The main factors influencing the inherent uncertainty of the models, such as the incompleteness of the actual knowledge and the intrinsic environmental and biological variability of the processes controlling the behaviour of radionuclides in rivers, are analysed.

EC computer systems in the field of hydrological dispersion modelling and aquatic radioecological research: state of the art, end-user experiences and recommendations for improvements

In the framework of the developments of the European system RODOS (Real-time On-line DecisiOn support System) for emergency response to nuclear accident, the computer code POSEIDON, that was developed to assess the radiological consequences of radioactive releases into marine environment, was adapted to cope with emergency conditions, in situations of radioactive discharges into the oceans from direct deposition from the atmosphere, sunken ships and containers, from discharges of rivers and estuaries and from coastal run-off. Based on the box model developed within the ‘Marina’ project, POSEIDON can calculate the dose effects from radionuclide releases in the coastal waters of Europe integrated over long time periods. A dynamic food chain model was implemented to deal with the short-term dynamical uptake of radioactivity by specific marine plants and organisms. POSEIDON has been installed on a UNIX platform to be fully compatible with RODOS input/output databases and on a Windows platform with an interface based on web technology. The 3D hydrodynamic model THREETOX is a part of the POSEIDON/RODOS system. It has been applied to coastal areas of the Baltic Sea, the Black Sea, and the North Sea, to derive the parameters for a flexible system of well-defined model compartments to be adapted to emergency conditions. The activity concentrations in water and in the marine food web were calculated by means of POSEIDON for radioactive fallout resulting from bomb testing, from the Chernobyl accident, and from routine discharges from nuclear facilities. POSEIDON’s model results were compared with measurement data, and with calculation results from THREETOX. The model results agreed with the measurement data sufficiently.

This paper is based on studies performed within the framework of the project Socio-Economic Research on Fusion (SERF3). Several fusion power plant designs (SEAFP Models 1–6) were compared focusing on part of the plant's life cycle: environmental impact of recycling the materials. Recycling was considered for materials replaced during normal operation, as well as materials from decommissioning of the plant. Environmental impact was assessed and expressed as external cost normalised with the total electrical energy output during plant operation. The methodology used for this study has been developed by the Commission of the European Union within the frame of the ExternE project. External costs for recycling, normalised with the energy production during plant operation, are very low compared with those for other energy sources. Results indicate that a high degree of recycling is preferable, at least when considering external costs, because external costs of manufacturing of new materials and disposal costs are higher.

This study was performed in the framework of the Socio-Economic Research on Fusion (SERF3), which is jointly conducted by Euratom and the fusion associations. Assessments of monetarized external impacts of the fusion fuel-cycle were previously performed (SERF1 and SERF2). Three different power plant designs were studied, with the main difference being the structural materials and cooling system used. In this third phase of the SERF project the external costs of three additional fusion power plant models using silicon carbide as structural material have been analysed. A comparison with other advanced generation technologies expected to be in use around 2050, when the first fusion power plant would be operative, has also been performed. These technologies include advanced fossil technologies, such as Natural Gas Combined Cycle, Pressurised Fluidised Bed Combustion and Integrated Gasification Combined Cycle with carbon sequestration technologies; fuel cells and renewable technologies including geothermal energy, wind energy and photovoltaic systems with energy storage devices. Fusion power plants using silicon carbide as structural material have higher efficiencies than plants using steel and this fact has a very positive effect on the external costs per kW h. These external costs are in the lowest range of the external costs of advanced generation technologies indicating the outstanding environmental performance of fusion power.

In the framework of research on inertial fusion, experiments on a reduced-scale prototype of the future Laser MegaJoule (LMJ) are planned in the ‘Laser Integration Line’ at CEA/DAM/CESTA. By 2005, part of these experiments will involve Deuterium–Tritium targets in which fusion reaction will result in radiation—mainly in the form of neutron flux and photon radiation from activated materials—that constitute a source of radiological exposure at the workplace. At the conception stage, an evaluation of the radiological exposures of occupational workers was performed. Different options for reducing these exposures have been studied. Results show that by modifying the composition of the staff or delaying the interventions, a reduction of the individual doses to the most exposed categories of employees from 2 to 50% to a factor 4 can be achieved, without increasing the total collective dose which can be further reduced by 10–25%. This study is a good illustration of how the ALARA principle can be implemented at the conception stage of an installation. Due to the low individual and collective exposures, the different options to reduce doses are more closely associated with staff and planning re-organisations. These options are characterised by a rather low cost and limited constraints of implementation.

The rise of the water level of the Pripyat river and the erosion associated with ice-jam events lead to the periodic inundation of the contaminated plain surrounding the Chernobyl power plant. This results in the re-suspension and dissolution of radioactive particles and their discharge into the Pripyat and Dnieper waters. This re-contamination of the Dnieper cascade is a significant source of exposure for the Ukrainian population living along the river. To reduce this radiological impact, a project of construction of a dyke on the right bank of the Prypiat river was elaborated. This paper gives an appraisal of this project. In a first phase, the estimated collective dose reduction associated with the construction of the dyke is presented. Then, the construction and maintenance costs of the dyke, as well as the expected benefits associated with dose reduction, are evaluated. The cost-benefit ratios which can be calculated on this basis are around unit, which tends to show that the benefits associated with the construction of the dyke would just compensate the construction and maintenance costs of the project. Taking account of the positive side effects on various sectors of the economy, this project would globally positively contribute to improve the living conditions of the Ukrainian population in a long term perspective.

The Chernobyl post-accident situation has highlighted how the sudden emergence of persistent radioactive contamination in the environment is severely affecting the quality of life of the inhabitants in the concerned territories. The management of this situation is complex, mainly conditioned by the ability of the inhabitants themselves to be directly involved in the process of improving their living conditions. In this process, quality of life cannot be restricted solely to the dimension of radiological risk, but needs to encompass the diverse aspects of daily living, including the social, psychological, economic, political and ethical aspects. This paper presents the experience of the involvement of a group of peasant farmers from a village in the Republic of Belarus, in the process of improving the radiological quality of privately produced milk. This experience took place in the context of the ETHOS project, funded by the radiation protection research programme of the European Commission. The principal objective was to implement a complementary approach to the rehabilitation strategies adopted so far in the contaminated territories of the Republic of Belarus. This paper retraces the process of involvement of the inhabitants in a working group. It describes the characterisation of the situation by local actors, the opening of new possible actions to improve the radiological quality of milk at the individual level and the positive consequences at the scale of the village. The ETHOS project also illustrates how the scientific knowledge accumulated over many years since the Chernobyl accident in the field of radiation protection and radioecology can enter into local practices in the form of practical tools, which can be used by the population to produce significant improvements in the radiological situation.

All the damages that are not reflected in the market price are called external costs. The external costs of fusion were elaborated with the ExternE methodology. The external costs are in the range of a few mEuro/kWh depending on the plant model. The external costs are in general not dominated by the impacts due to radioactive emissions and releases. All stages of the life cycle contribute significantly to the external cost value. The external costs of fusion are in the same range as the external costs of photovoltaics and wind energy.

Countermeasures have been effectively employed within intensive agricultural systems in areas of the Former Soviet Union (FSU) affected by the Chernobyl accident. However, ingestion doses continue to be elevated in some areas as a result of few foodstuffs which are collected from the wild or produced by the household. Forest fungi and berries, and milk from privately owned cattle are the most notable contributors to 137Cs intakes amongst these foodstuffs. In this paper we consider advice which would help affected populations to both understand the importance of these exposure routes and to reduce their exposure. In addition to the potential radiological benefits, self-help schemes are highly cost-effective and likely to have a positive psychological influence on populations living within contaminated areas of the FSU. Evidence to suggest that the transfer of radiocaesium to cow milk is considerably higher in the FSU than within western Europe and North America is discussed.

If measures to reduce greenhouse gas-emissions are taken and if fission will be phased out at the beginning of the 22nd century fusion has a good chance to win considerable shares of the electricity market. A detailed model of the Western-European energy system was made using the MARKAL toolkit. Scenarios were designed to understand the conditions that would make fusion a viable electricity production technique. Globally it is very likely that at least the first half of the 21st century will still be dominated by the use of fossil fuels, with a shift away from oil to natural gas. Energy and electricity demand are likely to increase over the complete 21st century.

Analysis of sensitivity and uncertainty of assessment models for external costs, which is monetarization of environmental impacts, of a commercial fusion plant were performed. The assessments covered the plant's entire life cycle, and adopted the ExternE methodology, which had been used to calculate external costs from other energy sources. Based on the SEAFP study, three different power plant designs were considered. The method developed in ExternE to estimate uncertainty gave very large ranges. A statistical error propagation method was employed for this study. Rather than as a single value, model input parameter values were given as distributions, from which random input sets of data were constructed. The models were then run with these sets, and the ensemble of output results was analysed statistically, yielding estimates of the uncertainty due to variation of the model parameteres. More information of parameter variation is needed for a more realistic estimation of model uncertainty, though. Sensitivity analyses were performed by varying all input parameters in a similar fashion. All model parameters were assumed to have a gaussian distribution with standard deviations of 10% of the mean value. The results pointed out the most essential parameters of the models. The sensitivity analyses are also useful for estimating the most effective ways to reduce the model computed external costs.

This study was performed in the framework of the Socio-Economic Research on Fusion (SERF 1999–2000), which is jointly conducted by Euratom and the fusion associations. An assessment of monetarized external impacts of the fusion fuel-cycle was previously performed applying the ExternE methodology (SERF-1), where, based on the SEAFP study, two different power plant designs were assessed, with the main difference being the structural materials and cooling system used. Although external costs values obtained were low, an improvement was achieved in the trade-off between design criteria and consequences on externalities. Structural and shielding materials in the previously studied plant models turned out to have a N-14 content that originated a significant amount of C-14 emissions. The present study includes alternative shielding materials with lower nitrogen content. With updated and improved technical and methodological inputs, a recalculation of externalities in the whole fusion fuel cycle was performed.

The radiological impact of an intense fusion economy, a 1000 GW operating capacity for a 1000 years, were investigated regarding the isotopes (14)C and tritium. Both isotopes,participate in global material cycles, the carbon and the water cycle. If a retention time of 10000 years is assumed for the stored waste, (14)C emissions from the repositories dominate the radiation impacts. While the cumulated collective doses over a long term period are rather high and according to the discount rate selected would lead to significant external costs, the individual doses are small compared with the doses associated with the natural background radiation. (C) 2001 Elsevier Science B.V. All rights reserved.