the ITER Vacuum Vessel Pressure Suppresion System Full-scale Test Facility: Numerical Analyses using Relap5

The principal objectives of this thesis are to assess the operability of the VVPSS small loca tank(SLT) following a reverse flow initiated by a an hydrogen-explosion/deflagration therein and to characterize the steam to be used for the VVPSS experiments in full-scale. The transient or the accident of reference in this study is an Ingress of Coolant event(ICE) of category IV. The water mass loss from the SLT during the reverse flow was calculated using a relap5 nodalization of the tank, the sparger system, the check valve and the vacuum vessel. a total water mass of 7231 kg was obtained and is within the design limits of operability. The full-scale facility was modeled in relap5, the steam discharges from the accumulators to the steam line were simulated. the steam throughout the line was characterized. A slight subcooling appeared in the steam and is the subject of further inquiries