Main outcomes relative to iodine behaviour from the VERDON/ISTP programme

Abstract : Following the TMI-2 accident in 1979, numerous programmes have been launched in France and abroad, in order to quantify the release or fission products (FP) from irradiated fuel and to better assess the source term under severe accident conditions. In France, the CEA has conducted the VERCORS programme, composed of 17 separate effect tests (SET), which is considered to be complementary to the integral-type PHEBUS-FP tests programme. After the successive shutdowns of the VERCORS (2002) and PHEBUS-FP (2004) facilities, a thorough identification of the remaining uncertainties in source term assessment and modelling was established by CEA, EDF and IRSN. This work led to the launch of the International Source Term Programme (ISTP)