Ex-Vessel Break in the ITER Divertor Cooling Loop Using the ECART Code

This work is related to the application of the CESI and Edf ECART code on the analysis of a large ex-vessel break in the divertor cooling loop of the ITER reactor. These activities are carried out in the general framework of the validation phase of the ECART code, initially developed by ENEL and EdF for integrated analysis of severe accidents in LWRs, for its application on incidental sequences related to the ITER fusion plant. ECART was originally designed and validated for traditional NPP safety analyses and it is internationally recognized as a relevant nuclear source term code for nuclear fission plants. It permits the simulation of chemical reactions and transport of radioactive gases and aerosols under two-phase flow transients in generic flow systems, using a built-in thermal-hydraulic model. A comparison of the ECART data with the results obtained by NFR Studsvik Nuclear AB (Nyköping, Sweden), utilising the MELCOR code in its fusion version for the same sequence, has been also performed during the present task. This comparison gives a quite good qualitative and quantitative agreement in the results, both for the thermal-hydraulics main parameters and the environmental radioactive releases