Severe accident simulation has been performed in the past to predict the energy release arising from hypothetical core disruptive accidents (CDA) postulated to occur in liquid-metal reactors (LMRs). This field has developed to a mature state with the creation of computer codes such as SIMMER, but these codes are highly specific to LMR designs. More recent attention has focused on thermal-spectrum criticality accidents. This has resulted in the creation of a new simulator code, A Transient History for Energetic Nuclear Accidents_2D (ATHENA_2D), which solves the transient multigroup space-time kinetics equations, coupled to multichannel thermal hydraulics and computational fluid dynamics. This paper presents results from two-dimensional kinetics simulations performed for a water reflood recriticality accident in a damaged light water reactor, typical of a Three Mile Island end-state core geometry. The accident is initiated by assuming reflood water that is insufficiently borated and a reactivity-optimized debris bed. Reactivity insertion rates analyzed in this study generally are smaller than in LMR CDAs (tens of dollars per second versus up to hundreds of dollars per second), and the energetics are slightly lower. Parametric variation of input was performed, including reactivity insertion rate and initial temperature.