The Multi-scale Atmospheric Transport and Chemistry Model (MATCH) is used in the RODOS (Real-time On-line decision Support) system since more than 10 years for the long range atmospheric transport and dispersion calculations. With the start of the EURANOS project, several functionalities of the model at that time should be further enhanced. This included the better use of the meteorological information available in the numerical forecast data and the coupling to the source term data base of the RODOS system.

Les spectres d’anthroporadiamétrie des sous-mariniers français embarqués sur sous-marins nucléaires lanceurs d’engins (SNLE) mettent en évidence une activité corporelle globale plus faible au retour de patrouille que lorsqu’ils sont à terre. Cette différence s’explique par l’absence de radon à bord des sous-marins après plusieurs jours de patrouille. Cette absence de radon conduit à une diminution de l’exposition des sous-mariniers à la principale source de rayonnement naturel. Par ailleurs, les conditions de plongée conduisent à une très forte atténuation des rayonnements tellurique et cosmique. En somme, les sous-mariniers embarqués sur SNLE présentent une moindre exposition aux principales sources d’exposition naturelle. Cette moindre exposition est globalement non compensée par un accroissement de l’exposition artificielle.

La présente note a pour objet d’exposer succinctement les techniques de scanners corporels pouvant être utilisés dans le cadre de la sûreté aéroportuaire. Les résultats d’études et d’expertises sur ces appareils ainsi que l’expérimentation en cours sur un scanner à ondes millimétriques sont également abordés. Elle présente la réglementation française en matière de protection des personnes contre les rayonnements ionisants déclinée à l’utilisation de scanners corporels à rayons X.

The 12th European ALARA Network (EAN) workshop on “ALARA issues arising for safety and security of radiation sources and security screening devices” took place in Vienna (Austria) in October 2009. The aim of that workshop was to consider how the implementation of ALARA, in terms of planned and emergency situations, involving worker and public doses, is affected by the introduction of security-related measures. In the case of new equipment and procedures, there was also the question of whether exposures arising from security screening devices can be justified and optimised. This workshop consisted of invited oral presentations, which highlighted the main issues, and half of the programme was devoted to discussions within working groups on specific topics. During their discussions, the working groups identified recommendations dealing with the following topics: the implementation of the Code of Conduct and HASS – ensuring ALARA; balancing security and safety – how to achieve an optimum solution; the management of an emergency exposure situation from an ALARA perspective; the justification and optimisation of the use of security devices. The objective of this paper is to present the main conclusions and recommendations produced during the workshop. Individual presentations (papers and slides) as well as the reports from the working groups are available to download on the EAN website (http://www.eu-alara.net).

During the EURANOS project three atmospheric dispersion models ATSTEP (ATSTEP, 2007), RIMPUFF (RIMPUFF, 1999), and DIPCOT (DIPCOT, 2009) used in the RODOS (Ehrhardt and Weis, 2000) decision support system were subject of comprehensive comparison and validation studies. The aim of the comparison exercise was a harmonisation of the models for a sample of representative, non-complex dispersion and deposition situations in the distance range below 100 km. Despite of different modelling and parameterisation the models should deliver similar results under these conditions. Furthermore validation studies were carried out with ATSTEP and DIPCOT using measured meteorological and contamination data from tracer dispersion field experiments. After minor model and parameter modifications final comparison calculations of the models with realistic numerical weather prediction (NWP) data have shown satisfactory consistency of the results.

For four German nuclear power plant sites and for Risø, the site of the Danish nuclear research reactors now being decommissioned, Numerical Weather Predictions (NWP) of wind speed and direction have been compared to 10 minute averaged local measurements. For the German sites the comparison covers data for approximately three month, January to March 2009, for the Risø site for approximately two thirds of the year October 1998 to September 1999. For each site the comparison has been made for all measurement levels and both for the NWP analysis time and for the maximum available forecast time. Means and standard deviations of NWP minus measured data are given as tables for all measurement levels while scatter plots are presented for only a single measurement level at analysis time at each site. For Risø and for the site close to the North Sea plus for the inland site Philippsburg the predictions of wind speed are on average rather close to the measured, but for sites not far from the latter two, Krümmel respectively Obrigheim, the discrepancies are substantial.

Contemporary open source JAVA technologies implemented within the EURANOS project for the cross-platform re-engineering of the decision support system RODOS (JRODOS) were used also to redesign the Hydrological Dispersion Module (HDM) of this system. JHDM – the hydrological model chain of JRODOS contains models to simulate the radionuclide transport in the system “atmospheric fallout on watershed – river net” and calculate the doses via aquatic pathways. JHDM used for this purpose a limited number of the input parameters to characterize the hydrological properties of the catchment/river network of interest. The pilot implementation of JHDM for the Vistula river basin carried out by POLATOM and supported by the national hydrological institute, demonstrated good perspectives of the approach used in JHDM for the decision support in cases of accidental contamination of water systems. Particular needs for further improvements of the JHDM software system have been identified.

Within the EURANOS project data assimilation (DA) approaches have been successfully applied in two areas to improve the predictive power of simulation models used in the RODOS and ARGOS decision support systems. For the areas of atmospheric dispersion modelling and of modelling the fate of radio-nuclides in urban areas the results of demonstration exercises are presented here. With the data assimilation module of the RIMPUFF dispersion code, predictions of the gamma dose rate are corrected with simulated readings of fixed detector stations. Using the DA capabilities of the IAMM package for mapping the radioactive contamination in inhabited areas, predictions of a large scale deposition model have been combined with hypothetical measurements on a local scale. In both examples the accuracy of the model predictions has been improved and the uncertainties have been reduced.

In nuclear and radiological emergency and post-accident management decisions on countermeasures and remediation strategies have to be made. Whereas in the early phase decisions on emergency actions must be made in a very short time, according to emergency plans and dose thresholds, in the recovery phase complexity is higher. But there is also more time for evaluating alternative countermeasures and remediation strategies with respect to several goals. In this paper evaluation strategies supporting the decision makers throughout all phases are presented. The applied decision support techniques range from graphical presentations of decision relevant information about the alternatives for action to multi-criteria decision making (MCDM) methods. In particular methods to cope with several types of uncertainties inherent in the different phases are presented. By the integration of these techniques, the decision support system RODOS is able to provide support for more conscious, transparent and coherent decision making.

One key issue in the EURANOS project was the methodological and technological improvement of decision support systems, in particular the RODOS system, with respect to the practical application in operational emergency centres. The development process was mainly driven by the result of demonstration activities and responses obtained from the end-users in the emergency centres. The intention of this article is to give an overview of all major work items which have been performed within EURANOS with the aim of improving decision support systems. More details about several of these activities can be found in separate articles in this issue.