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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. [ABSTRACT FROM AUTHOR]

This paper presents three approaches to find optimized grids for atmospheric dispersion measurements and calculations in emergency planning. This can be useful for deriving optimal positions for mobile monitoring stations, or help to reduce discretization errors and improve recommendations. Indeed, threshold-based recommendations or conclusions may differ strongly on the shape and size of the grid on which atmospheric dispersion measurements or calculations of pollutants are based. Therefore, relatively sparse grids that retain as much information as possible, are required. The grid optimization procedure proposed here is first demonstrated with a simple Gaussian plume model as adopted in atmospheric dispersion calculations, which provides fast calculations. The optimized grids are compared to the Noodplan grid, currently used for emergency planning in Belgium, and to the exact solution. We then demonstrate how it can be used in more realistic dispersion models. [ABSTRACT FROM AUTHOR]

Abstract: An environmental risk assessment (ERA) was performed to evaluate the impact on non-human biota from liquid and atmospheric radioactive discharges by the Belgian Nuclear Power Plants (NPP) of Doel and Tihange. For both sites, characterisation of the source term and wildlife population around the NPPs was provided, whereupon the selection of reference organisms and the general approach taken for the environmental risk assessment was established. A deterministic risk assessment for aquatic and terrestrial ecosystems was performed using the ERICA assessment tool and applying the ERICA screening value of 10 μGy h−1. The study was performed for the radioactive discharge limits and for the actual releases (maxima and averages over the period 1999–2008 or 2000–2009). It is concluded that the current discharge limits for the Belgian NPPs considered do not result in significant risks to the aquatic and terrestrial environment and that the actual discharges, which are a fraction of the release limits, are unlikely to harm the environment. [Copyright &y& Elsevier]

In April 2020, several wildfires took place in and around the Chernobyl exclusion zone. These fires reintroduced radioactive particles deposited during the 1986 Chernobyl disaster into the atmosphere, causing concern about a possible radiation hazard. Several countries and several stations of the International Monitoring System measured increased Cs137 levels. This study presents the analyses made by RIVM and SCK CEN/RMI during the April 2020 wildfires. Furthermore, more in-depth research was performed after the wildfires. A statistical analysis of Cs137 detections is presented, comparing the April 2020 detections with historical detections. Inverse atmospheric transport modelling is applied to infer the total released Cs137 during the wildfires. Finally, it is assessed whether the Cs137 detections in Belgium and the Netherlands can be attributed to the wildfires., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)