Environment source terms for a few NET plant reference accident sequences

The paper presents the environment source terms (EST) associated with some reference accident sequences (RAS) for the Basic Performance Phase of the Next European Torus (NET). Only activated materials have been taken into account as radioactive inventory (RI). The activation products have been estimated via the ANITA code, using an updated neutron cross section library based on REAC-ECN-5 and EAF3 evaluation files. Various materials in the inboard and outboard zones of NET design (AISI 316L, carbon fiber compound, tungsten, and boron carbide for the PFC, and water as coolant) and operating conditions (normal running and conditioning) are considered and assessed. The process source terms (PST) related to some RAS are identified and estimated, by considering the mechanisms leading to RI mobilisation for the RAS of concern (e.g. corrosion/erosion). The FUMO code has been used to estimate the thermal-hydraulic conditions inside the containment for the accident sequences in-vessel and ex-vessel LOCA. The PST transport and deposition in the containment are evaluated by using the NAUA code, running on personal computers, in order to define the released fraction from the last containment