The new recommendations on emergency exposure situations of the International Commission on Radiological Protection (ICRP) advise a reference level for the residual dose in a range of between 20 and 100 mSv effective dose (acute or per year). At the same time, the protection strategy should account for the simultaneous consideration of all the exposure pathways, as well as all of the protective actions. Similarly to other countries, the actual Belgian nuclear emergency plan is based on individual projected doses (thyroid committed dose and total effective doses) and independent protective actions that mainly focus on the early phase of an emergency situation. The two approaches are compared in this study on the basis of the projected and residual dose calculations obtained using JRODOS and the Belgian Noodplan models for different radiological or nuclear accidental scenarios. The comparison has been made by considering separately the early and the late phase contributions. The ingestion dose has been investigated from the predicted deposition values and compared to the single level of the ICRP 109 recommendations.

The improved use of collective dose following the 2007 ICRP recommendations is studied for nuclear and radiological emergency situations. To study the accumulation of low individual doses to the collective dose the collective dose is calculated as a function of the minimum individual dose for three cases including nuclear as well as radiological accidents. It is found that the use of collective dose in this way can have an added value in nuclear emergency preparedness and response in particular related to decisions on overall protective actions following an accident.

Generic guidance on the withdrawal of sheltering, withdrawal of evacuation and evacuation of sheltered populations (displacement) has been developed based on previously unpublished work in the UK and France and on input from stakeholder panels in Germany, Belgium, France and the UK. The guidance is a living document that can be developed further in the future, both in its generic form and also as customised versions in some Member States. The guidance outlines the many factors which influence the withdrawal of emergency countermeasures: official confirmation that any release has stopped; adequacy of monitoring data; radiological criteria; radiological protection advice; availability of resources; social and psychological needs; stakeholder dialogue; and communication strategy. The relative importance placed by decision makers on each of these criteria would vary according to the nature and scale of the accident and also on socio-political, economic and cultural perspectives. In the event of a radiological incident, decision makers will need to be in a position to construct a strategy for managing the withdrawal of emergency countermeasures. For larger scale, longer duration releases involving several nuclides, a management strategy is likely to be complex. The guidance therefore includes a series of checklists which have been developed in conjunction with stakeholders to take into account the main criteria and factors which should be considered.

Within the IAEA EMRAS programme, a working group was established to look at the modelling of naturally occurring radioactive material (NORM) in a variety of environments. There are many models already available. However, guidance on how and when to apply specific models is lacking in many cases. Development of models has often been carried out without a clear understanding of the possible applications of the models. Some models have been developed only for specific applications in specific industries, and are not generally useful. The work carried out during this program has resulted in the identification of several important issues that require consideration in the selection and utilization of computer models for NORM risk assessment. These issues discussed below cover suitability, selection, use and misuse of available models, as well as training and guidance for modelers, and acquisition of data for model inputs.

There is general international acceptance of the need to demonstrate that the environment is protected from ionising radiation. In some countries requirements and guidelines for the protection of non-human biota are already in place. As a consequence a number of models and approaches have been proposed for the estimation of the exposure of non-human biota to ionising radiation. The IAEA EMRAS programme's Biota Working Group has conducted the most comprehensive intercomparison of the predictions of these approaches to date. In this paper, we present an overview of the activities of the Biota Working Group concentrating on its conclusions and recommendations.

The BioMoSA (Biosphere Models for Safety Assessment of Radioactive Waste Disposal) project was part of the EC fifth framework research program. The main goal of this project was the improvement of the scientific basis for the application of biosphere models in the framework of long-term safety studies of radioactive waste disposal facilities. Another aim of the project was to provide operators and regulatory bodies with guidelines for performance assessments of repository systems. The study focused on the development and application of site-specific models and a generic biosphere tool BIOGEM (BIOsphere GEneric Model), using the experience from National programs and the IAEA BIOMASS reference biosphere methodology. The models were applied to 5 typical locations in Europe, resulting in estimates of the annual individual doses to the critical groups and the ranking of the importance of the pathways for each of the sites. The results of the site-specific and generic models were then compared. Uncertainty in the results was estimated by means of stochastic calculations which allowed a comparison of the overall model uncertainty with the variability across the different sites considered.

Tea (Camellia sinensis) clones (PC113 and SFS204) sensitive to very dry air and clones (PC114 and SFS150) that are tolerant, were studied at two tea estates (Tshivhase and Grenshoek) in the Northern Province of the Republic of South Africa. Among the morphological leaf traits studied, stomatal density, pore diameter and pore depth were not linked consistently to stress tolerance. Cuticle thickness was not a good indicator of stress tolerance because genetic differences between clones were confounded by the clonal response of wax production to stress. In contrast, measured leaf conductance to water vapour transport was larger and leaf water potential was lower in sensitive clones, but only with more severe atmospheric stress (Grenshoek). Also the ratio of the calculated maximum stomatal conductance in old and young leaves was higher in sensitive clones, suggesting that the loss of a larger fraction of the total stem flow by old leaves enhanced the stress experienced by the young leaves. However, this indicator was valid only under the more stressful microclimate of Grenshoek. The results indicate that even promising criteria for stress tolerance should be tested by exposure to stress during selection.