CFD investigating thermal-hydraulic characteristics and hydrogen generation from graphite-water reaction after SG tube rupture in HTR-10 reactor

► We propose a CFD model to investigate thermal-hydraulic characteristics within the HTR-10 core. ► Four postulated accidents, with ruptures in one and two SG tubes, respectively, are investigated. ► During postulated accidents, the generation amount of H2 is not sufficient to induce the explosion. ► The peak coolant temperatures during transients are also predicted to be lower than the limiting value.