Evaluation of high-temperature behavior of sacrificial concrete in nuclear reactor core containment structures

摘要

Sacrificial concrete is a cement-based material used for fire protection purposes. It is commonly used as a protective layer in nuclear reactor core containment structures in nuclear power plants. Its purpose is to act as a protection material only. Sacrificial concrete is particularly effective in protecting nuclear reactor core containment because it possesses high temperature stability and high melt capability that can reduce or help avoid the deterioration due to ultra-high temperature exposure from nuclear reactor core accidents or meltdowns. Sacrificial concrete is used in European pressurized reactors (EPRs), as an example, to contain molten core melts by melting a sacrificial concrete layer within the containment, which helps to cool the molten core and assists in avoiding a hot melt on the load-bearing containment structure. The study of performance of sacrificial concrete in ultra-high temperature exposures is in its early stages. To investigate the behavior and properties of sacrificial concrete at the ultra-high temperature of 5430°F (3000°C), numerical modeling simulating the same environment of a nuclear accident is established. Results indicate that the water-cementitious materials ratio (w/cm) and mineral admixtures have a significant impact on compressive strength, water loss, and water content of sacrificial concrete. Mixture proportions presented in this paper possess outstanding spalling resistance and melting behavior. Even at ultra-high temperatures, the sacrificial concrete possesses good melting behavior, and the melt depth of sacrificial concrete increases proportionally with time, which can effectively reduce the detriment of a nuclear accident.