In April 2011 the European Platform on Preparedness for Nuclear and RadiologicalEmergency Response and Recovery (NERIS-TP) decided to expand the two European DecisionSupport Systems JRodos and ARGOS with respect to the new ICRP-103 recommendations. Theextension should be applicable for nuclear accidents and radiological emergencies andcomprise a new screening model, the possibility to optimise dose reducing actions with themodels ERMIN (European Model for Inhabited Areas) and AGRICP (Agricultural CountermeasureProgram), respectively, and scenario preparation tools to support the user in definingcountermeasure strategies. This paper describes the screening model that was developed bythe authors and is foreseen for realisation and inclusion in JRodos and ARGOS in2012/2013.

As part of the ongoing European project NERIS-TP, a revision has been made of someparameters influencing dose estimates in the European emergency management decisionsupport systems RODOS and ARGOS. On the basis of survey data, the estimates of the timefractions typically spent indoors and outdoors over longer time periods have been revised.On the basis of measurement data, also new values for the natural ventilation rategoverning early ingression of contaminants into dwellings have been derived for differentparts of Europe. Other potential parameterisation improvements for the decision supportsystems are discussed.

With the ICRP recommendations Publications 103, 109 and 111 (ICRP, 2007; ICRP 2009a,2009b), new concepts and quantities have been introduced into emergency management andrehabilitation. Two of them will possibly influence national procedures, but for sure theywill influence countermeasure simulation approaches: 1. The concept of a “reference level”for emergency and existing controllable exposure situations that represents the level ofdose or risk, above which it is judged to be inappropriate to plan to allow exposures tooccur, and for which therefore protective actions should be planned in advance. 2. Whendeciding on the optimum course of protective actions, all exposure pathways and allrelevant actions have to be taken into account. The major changes for the simulationmodels result from the second recommendation that all exposure pathways must be consideredwhen deciding on protective actions. So far all countermeasure simulations in the earlyphase of an emergency are carried out by considering individual countermeasures such assheltering or evacuation, if some dose limit for the respective action is exceeded. Thisapproach has to be changed and strategies of several countermeasures analysed andsimulated with the ultimate goal not to exceed the reference level over a given timeperiod, typically one year.