ASTEC - RAVEN coupling for uncertainty analysis of an ingress of coolant event in fusion plants

Abstract

The integrated ICE (Ingress-of-Coolant Event) facility, scaled 1/1600 with respect to the ITER-FEAT design, was built at JAERI with the aim of reproducing the phenomenology occurring in an ICE accident. An ICE occurs when a rupture in the coolant pipes causes the pressurized coolant to enter into the Plasma Chamber, which is held under high vacuum condition. A suppression system is used to mitigate the overpressurization and to prevent mechanical damages to the structures. The CPA module of the ASTEC severe accident code (Study carried out with ASTEC V2, IRSN all rights reserved, [2020]), has been adopted for the modelling and the simulation of a test conducted in the ICE facility. The experimental results of the main thermal-hydraulic parameters have been compared to the code results to characterize the ASTEC capability to predict the phenomenology of a low-pressure two-phase flow transient occurring in a fusion reactor. By coupling the ASTEC code with the uncertainty tool RAVEN, developed by Idaho National Laboratory, an uncertainty analysis has been conducted on the transient. The aim of the present activity is to investigate the dispersion and the sensitivity of the code response to the variation of selected uncertain input parameters, which could influence the simulation of an ICE. The activity also provides a first application of uncertainty analysis through the RAVEN-ASTEC coupling.