Analysis of a Loss-of-Flow Accident (LOFA) in a tokamak superconducting toroidal field coil

The ITER tokamak is under construction in France and the EU hopes to produce the first kWh from the magnetically-confined fusion reactor DEMO by mid of this century. The superconducting magnet system guarantees the plasma confinement and is the most expensive component of the reactor. Here we present a first step in the analysis of accidents, which may occur in a tokamak magnet system. An undetected Loss-of-Flow Accident (LOFA) in the ITER Toroidal Field (TF) magnets during a standard plasma pulse is simulated with the validated 4C thermal-hydraulic code. The evolution of the most relevant thermal-hydraulic variables is computed and compared with the nominal operation to show deterministically the consequences of the LOFA. The accident can lead to a quench of the magnet, a transient which can cause a damage of the component—with consequent loss of plasma confinement and reduced availability of the machine.