Thermal-Spectrum Recriticality Energetics

Large computer codes have been created in the past to predict the energy release in hypothetical core disruptive accidents (CDA) postulated to occur in liquid-metal reactors (LMRs). These codes, such as SIMMER, are highly specific to LMR designs. More recent attention has focused on thermal-spectrum criticality accidents such as for fuel storage basins and waste tanks containing fissile material. This paper presents results from recent one-dimensional kinetics simulations, performed for a recriticality accident in a thermal spectrum. Reactivity insertion rates generally are smaller than in LMR CDAs, and the energetics generally are more benign. Parametric variation of input was performed, including reactivity insertion and initial temperature.