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 rangeatmospheric transport and dispersion calculations. With the start of the EURANOS project,several functionalities of the model at that time should be further enhanced. Thisincluded the better use of the meteorological information available in the numericalforecast 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-marinsnucléaires lanceurs d’engins (SNLE) mettent en évidence une activité corporelle globaleplus faible au retour de patrouille que lorsqu’ils sont à terre. Cette différences’explique par l’absence de radon à bord des sous-marins après plusieurs jours depatrouille. Cette absence de radon conduit à une diminution de l’exposition dessous-mariniers à la principale source de rayonnement naturel. Par ailleurs, les conditionsde plongée conduisent à une très forte atténuation des rayonnements tellurique etcosmique. En somme, les sous-mariniers embarqués sur SNLE présentent une moindreexposition aux principales sources d’exposition naturelle. Cette moindre exposition estglobalement non compensée par un accroissement de l’exposition artificielle.

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

The 12th European ALARA Network (EAN) workshop on “ALARA issues arising for safety andsecurity 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 implementationof 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 equipmentand procedures, there was also the question of whether exposures arising from securityscreening devices can be justified and optimised. This workshop consisted of invited oralpresentations, which highlighted the main issues, and half of the programme was devoted todiscussions within working groups on specific topics. During their discussions, theworking groups identified recommendations dealing with the following topics: theimplementation of the Code of Conduct and HASS – ensuring ALARA; balancing security andsafety – how to achieve an optimum solution; the management of an emergency exposuresituation from an ALARA perspective; the justification and optimisation of the use ofsecurity devices. The objective of this paper is to present the main conclusions andrecommendations produced during the workshop. Individual presentations (papers andslides) as well as the reports from the working groups are available to download on theEAN 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 validationstudies. The aim of the comparison exercise was a harmonisation of the models for a sampleof representative, non-complex dispersion and deposition situations in the distance rangebelow 100 km. Despite of different modelling and parameterisation the models shoulddeliver similar results under these conditions. Furthermore validation studies werecarried out with ATSTEP and DIPCOT using measured meteorological and contamination datafrom tracer dispersion field experiments. After minor model and parameter modificationsfinal 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 nuclearresearch reactors now being decommissioned, Numerical Weather Predictions (NWP) of windspeed and direction have been compared to 10 minute averaged local measurements. For theGerman sites the comparison covers data for approximately three month, January to March2009, for the Risø site for approximately two thirds of the year October 1998 to September1999. For each site the comparison has been made for all measurement levels and both forthe NWP analysis time and for the maximum available forecast time. Means and standarddeviations of NWP minus measured data are given as tables for all measurement levels whilescatter plots are presented for only a single measurement level at analysis time at eachsite. For Risø and for the site close to the North Sea plus for the inland sitePhilippsburg 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, thediscrepancies are substantial.

Contemporary open source JAVA technologies implemented within the EURANOS project for thecross-platform re-engineering of the decision support system RODOS (JRODOS) were used alsoto redesign the Hydrological Dispersion Module (HDM) of this system. JHDM – thehydrological model chain of JRODOS contains models to simulate the radionuclide transportin the system “atmospheric fallout on watershed – river net” and calculate the doses viaaquatic pathways. JHDM used for this purpose a limited number of the input parameters tocharacterize the hydrological properties of the catchment/river network of interest. Thepilot implementation of JHDM for the Vistula river basin carried out by POLATOM andsupported by the national hydrological institute, demonstrated good perspectives of theapproach used in JHDM for the decision support in cases of accidental contamination ofwater systems. Particular needs for further improvements of the JHDM software system havebeen identified.

Within the EURANOS project data assimilation (DA) approaches have been successfullyapplied in two areas to improve the predictive power of simulation models used in theRODOS and ARGOS decision support systems. For the areas of atmospheric dispersionmodelling and of modelling the fate of radio-nuclides in urban areas the results ofdemonstration exercises are presented here. With the data assimilation module of theRIMPUFF dispersion code, predictions of the gamma dose rate are corrected with simulatedreadings of fixed detector stations. Using the DA capabilities of the IAMM package formapping the radioactive contamination in inhabited areas, predictions of a large scaledeposition model have been combined with hypothetical measurements on a local scale. Inboth examples the accuracy of the model predictions has been improved and theuncertainties have been reduced.

In nuclear and radiological emergency and post-accident management decisions oncountermeasures and remediation strategies have to be made. Whereas in the early phasedecisions on emergency actions must be made in a very short time, according to emergencyplans and dose thresholds, in the recovery phase complexity is higher. But there is alsomore time for evaluating alternative countermeasures and remediation strategies withrespect to several goals. In this paper evaluation strategies supporting the decisionmakers throughout all phases are presented. The applied decision support techniques rangefrom graphical presentations of decision relevant information about the alternatives foraction to multi-criteria decision making (MCDM) methods. In particular methods to copewith several types of uncertainties inherent in the different phases are presented. By theintegration of these techniques, the decision support system RODOS is able to providesupport for more conscious, transparent and coherent decision making.

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