ASTEC code validation versus ICE P1-P8 experiments: comparison of two different experiences

ASTEC is a system code developed by IRSN for the analysis of Severe Accidents in fission nuclear reactors. In recent years, the code has been extended to cope also with incidental transients in fusion installations. The scope of the present work is to provide a validation of the ASTEC code against the 8 tests performed in the upgraded Ingress of Coolant Event (ICE) facility. This facility is a scaled reproduction of the Pressure Suppression System (PSS) of the ITER machine. The simulations of the different tests have been performed by two different teams, one formed by C.r.e.a.t.e and ENEA researchers and the second one by University of Pisa and IRSN researchers. Main goal of these validation activities conducted by both teams is to confirm that ASTEC is indeed able to globally model the progression and consequence of an in-vessel LOCA in the ITER facility and to identify, through sensitivity analyses, the phenomena for which additional R&D efforts are needed. In both cases the initial ICE experimental data have been treated as boundary conditions. All the assumptions and the nodalization choices have been extensively justified. Interesting outcomes have been obtained because ASTEC demonstrated to fit the most part of the phenomena involved in the accidental transients, but fails to follow some of them, i.e., the jet impingement effect. The two groups verified independently these problems.