The Decision Support System of PSI, and how it Meets the Needs of the Users

Four categories of users of a decision support system (DSS) are characterised particularly with respect to their know-how and needs: scientists, technicians, radiation safety officers and decision makers. The capabilities of a modern DSS of high performance lie in reliability, flexibility and user-friendliness. These features are put into perspective of the potential user needs, which are not necessarily compatible. Missing know-how has to be compensated either by expert judgement or by more complex monitoring and modelling. The DSS structure at PSI allows capabilities of different performance to be grouped in basically to levels of problem complexity with two operational levels (interactive or automatic) each to four modes, which are compatible with different users' needs. The system is designed to simulate the atmospheric transport of radioactive effluents in flat and complex terrain in real time. The automatic operation of a DSS - with all its limitations - is an important step to a better overall performance of the system even for difficult problems such as atmospheric transport in complex terrain; particularly, in connection with data assimilation for unknown releases. So far, the challenge of meeting the needs of most DSS users is achievable.