The interaction between off-site decision making, decision support systems, modelling and monitoring in a nuclear emergency situation

The interaction and inter-dependence between decision making, Decision Support Systems (DSS) and measurements in a radiological emergency situation is discussed. Data and DSS products of importance are identified in different phases of an accident. Planning of decision making must focus on comprehensible and clear concepts. In the early phase, clear and unambiguous model prognoses are needed for fast decision making. However, the input data are highly uncertain and disputable. During cloud passage the options for decision making are limited. After cloud passage, decision making and monitoring are highly interactive and the efficacy of countermeasures requires that both DSS and measurement programmes be well tailored. Data must be representative and of sufficient number where decisions refer to Derived Emergency Reference Levels (DERL for food and feed). In the late phase, the DSS should enable decision makers to balance cost, environmental impact, averted dose and adverse psychological effects.