In the last 20 years the Work Group on Severe Accidents has participated to the main international research programmes in this nuclear safety field, focusing on the development and assessment of simulation models for booth the “in-vessel” and “ex-vessel” phase of a severe accident. In particular, for the “in-vessel” phase, “ad hoc” original model (TCM) for the hydrogen production during the core quenching in the reflood phase of a severe accident has been developed. Furthermore, international codes, as SCDAP/RELAP5, MELCOR and FLUENT, have been widely utilised.
The research activities have been carried out inside EU Projects, with international partners as CEA (F) and FZK (D).
These new models and tools are a fundamental part of the DIMNP methodology for the safety analysis of a nuclear plant, recently applied for advanced reactors in severe accident conditions. The results of these DIMNP safety analysis have been utilised by Westinghouse and GE for the licensing of the AP600 and SBWR. For the European EPP and EPR, these evaluations are a part of the Italian contribution in the two projects. For these new reactors, DIMNP started the “integrated” approach by upgrading the FUMO code, developed to analyse containment transients, with the introduction of a simplified PS module and validating the new code. This new version allows the containment loads evaluation in various accident conditions and its several models covers a wide spectrum of physical processes as the hydrogen combustion and the corium-water interaction.
A realistic evaluation of radionuclide transport has required the participation at the development of the ECART code, for an integrated evaluation of system thermalhydraulic, fission products retention and chemical equilibria. CESI/EdF promoted the code, aimed at unifying primary and containment analyses, validated by DIMNP on the PHEBUS FP tests, analysed also using the CFD FLUENT code.


Contact persons
Prof. F. Oriolo E-mail This e-mail address is being protected from spambots. You need JavaScript enabled to view it
Prof. S. Paci E-mail This e-mail address is being protected from spambots. You need JavaScript enabled to view it