Modeling of Reinforced Concrete for Reactor Cavity Analysis under Energetic Steam Explosion Condition

BackgroundSteam explosions may occur in nuclear power plants by molten fuel–coolant interactions when the external reactor vessel cooling strategy fails. Since this phenomenon can threaten structural barriers as well as major components, extensive integrity assessment research is necessary to ensure their safety.MethodIn this study, the influence of yield criteria was investigated to predict the failure of a reactor cavity under a typical postulated condition through detailed parametric finite element analyses. Further analyses using a geometrically simplified equivalent model with homogeneous concrete properties were also performed to examine its effectiveness as an alternative to the detailed reinforcement concrete model.ResultsBy comparing finite element analysis results such as cracking, crushing, stresses, and displacements, the Willam–Warnke model was derived for practical use, and failure criteria applicable to the reactor cavity under the severe accident condition were discussed.ConclusionIt was proved that the reactor cavity sustained its intended function as a barrier to avoid release of radioactive materials, irrespective of the different yield criteria that were adopted. In addition, from a conservative viewpoint, it seems possible to employ the simplified equivalent model to determine the damage extent and weakest points during the preliminary evaluation stage.