A core catcher is a device provided to catch the molten core material (Corium) of a nuclear reactor in case of a nuclear meltdown and prevent it from escaping the containment building.
A core catcher is made from a special concrete ceramic to prevent material from trickling through; it also uses material of cooler construction to cool down the core material.[1][2] The core catcher of the European Pressurized Reactor (EPR) has 170 m² expansion area and a mass of 500 t.[3]
Reactor types with core catchers, besides the EPR, are: the "Fast Breeder" SNR-300,[4] VVER-1000/428,[5] SWR1000, ESBWR, and Atmea I.[4]
The AES-91, a project of Atomstroyexport, will be the first type of nuclear plant that has a core catcher as standard equipment.[6] Thus, in early 2011, the two reactors of the Chinese Tianwan Nuclear Power Plant are the only working nuclear reactors with core catchers.