Revisiting the analysis of passive plasma shutdown during an ex-vessel loss of coolant accident in ITER blanket

In this contribution, the analysis of passive safety during an ex-vessel loss of coolant accident (LOCA) in the first wall/shield blanket of ITER has been studied with AINA safety code. In the past, this case has been studied using robust safety arguments, based on simple OD models for plasma balance equations and 10 models for wall heat transfer. The conclusion was that, after first wall heating up due to the loss of all coolant, the beryllium evaporation in the wall surface would induce a growing impurity flux into core plasma that finally would end in a passive shut down of the discharge. The analysis of plasma-wall transients in this work is based in results from AINA code simulations. AINA (Analyses of IN vessel Accidents) code is a safety code developed at Fusion Energy Engineering Laboratory (FEEL) in Barcelona. It uses a 0D/1D architecture, similar to that used for past analyses. Initial results show good agreement with previous studies, plasma shutdown happens before significant melting occurs in first wall. However, after a parametric survey a new scenario was identified with the potential not only to melt beryllium but also the copper heat sink. If the coolant tubes were compromised in such scenario, the in-vessel radioactive inventory could be mobilized. http://nerg.upc.edu/ (C) 2015 Elsevier B.V. All rights reserved.