Modelling an in-vessel loss of coolant accident in the EU DEMO WCLL breeding blanket with the GETTHEM code

Abstract

One of the accidents to be analyzed for the operation of the EU DEMO tokamak reactor is the in-vessel Loss-Of-Coolant Accident (LOCA), in which a postulated rupture in the First Wall causes a rapid pressurization of the Vacuum Vessel (VV). To avoid rupture of the VV, a VV Pressure Suppression System (VVPSS) is used, which is aimed at removing the coolant from the VV, preserving its integrity and safely storing the coolant together with the radioactive products contained therein. A system-level tool for the analysis of thermal-hydraulic transients in tokamak fusion reactors, called GEneral Tokamak THErmal-hydraulic Model (GETTHEM), is under development at Politecnico di Torino. This paper presents the GETTHEM module developed for the description of the EU DEMO VVPSS, in the case of a water-cooled Breeding Blanket concept; the code validation against experimental data coming from the Ingress of Coolant Event campaign performed in Japan is shown. The tool is then applied to a parametric analysis relevant for an EU DEMO in-VV LOCA, and the results are presented and discussed.