Based on the updated ITER-EDA design information from ITER Joint Central Team, some accident scenarios previously defined have been reviewed and updated.

So far, the Environmental Source Terms (EST) associated to small and large ex-vessel loss of coolant accident sequences in ITER divertor primary heat transfer system (DV LOCA accidents) have been firstly assessed. The success of the Fusion Safety Shutdown System (FSSS) has been considered in assessing those accident sequences. The activated materials (tritium and corrosion products) contained in the DV primary loop have been considered as the potential mobilizable inventories. The transient thermal-hydraulic analysis has been studied using the ATHENA code and the INTRA code has been used to assess the containment response to the accident. Finally, the NAUA Mod 5M code has been used to obtain the environmental releases associated to the radioactive inventories mobilised. Soil and stack releases are evaluated, both for tritium and activated materials, up to seven days from the accidents. The radioactive inventories, tritium and activated corrosion products (ACP) in the failed cooling loop, provided by ITER JCT, and those assessed by the PACTOLE code (for ACP only), have been considered to evaluate the EST.

The environmental releases have been estimated also for accident sequences initiated by a loss of flow (DV LOFA accidents) in a DV PHTS loop. In case of plasma burn stop due to the success of the FSSS, the primary boundary of the heat transfer system maintains its integrity. Therefore no radioactive inventory is mobilised and no environmental release results from that accident. On the contrary, the failure of the FSSS provokes an in-vessel LOCA from the divertor primary cooling loop and this results in a mobilisation of radioactive inventories towards the lower an upper vaults. The accident sequence analysis has been performed using the three codes ATHENA, INTRA and NAUA. The radioactive inventories (tritium and ACP in the failed cooling loop, and the tritium and the activated dust inside the plasma chamber) have been considered to evaluate the EST. Finally, the environmental release has been evaluated for a loss of primary vacuum accident (LOVA accident). The tritium and the activated dust contained inside the plasma chamber have been considered as potential mobilizable inventories for that accident. The INTRA and NAUA codes have been used for the EST evaluation.