Simulation of runaway electron generation in the Day-0 scenario of DTT

Formation of Runaway electrons (REs) during tokamak disruptions is a significant challenge in fusion research, as they can locally damage the plasma-facing components by applying thermal loads of tens of MJ per square meter, possibly leading to significant melting. This work investigates the current quench phase of disruptions and the likelihood of RE generation and multiplication in the Day-0 scenario (plasma current I p = 2 MA) of the Divertor Tokamak Test (DTT), using the non-linear magnetohydrodynamic code JOREK. Our results from 2D (toroidally symmetric) simulations indicate that, in this initial low-current scenario, RE generation is minimal to negligible when the impurities injected through disruption mitigation systems are adequately limited. This suggests that DTT’s early operational phase poses a low RE risk, contributing to operational safety in this regard before transitioning to full power scenarios ( I p = 5 . 5 MA). In addition to providing an initial RE safety benchmark for DTT, this study lays the groundwork for further research at higher operational currents and for the estimation of heat loads caused by RE beams on plasma-facing components, essential for guiding the design and strategic placement of mitigation elements such as sacrificial limiters. • Runaway electrons pose minimal risk in DTT’s early low-current operational phase. • Impurity control prevents runaway electron avalanches during plasma disruptions. • Moving to full-current scenarios raises runaway electron risk, requiring mitigation.