TOWARDS A MONITORING FRAMEWORK FOR THE SOURCE-TERM ESTIMATION DURING THE EARLY PHASE OF AN ACCIDENTAL RELEASE AT A NUCLEAR-POWER-PLANT

In the RODOS project data assimilation methods are under development t o assess the radiological situation in real time in case of an acciden t at a nuclear power plant. Due to the short time available to take de cisions during the early phase a judicious combination of model predic tions and monitoring data will have to be used. It is shown that actua l site-specific monitoring strategies in Europe are not adapted to thi s new method. A new site-specific monitoring framework is proposed. As similation of simultaneous on-line gamma dose rates from detectors loc ated around an installation constitutes the first and principal source of information to assess the magnitude of the release. Complementary mobile monitoring of particulates, iodine and noble gases can then dir ectly be correlated to the gamma dose rates. The information about the exact monitoring location is not used, provided the three components are sampled simultaneously in a beta field.