Core Catcher in a Nuclear Reactor

Moscow based Rosatom state corporation has installed a core catcher or a core melt installation device at the Unit 3 of Kundakulam Nuclear Power Plant at Tamil Nadu.

A core catcher is a device designed to cool and localise the molten core material in case of a meltdown accident. The molten core material or corium is a a lava like material which get formed in the core of a nuclear reactor in case of a meltdown. Such a situation may occur when the nuclear fission reaction taking place inside the reactor is not cooled enough. The result is a buildup of heat which causes the fuel rods to melt down.

Previous meltdown accidents include the Chernobyl disaster in Russia in 1996 and the Fukushima accident in Japan, 2011. The core catcher is a cone shaped metal structure with a weight of around 800 tonnes. It is double waled with a gap between two walls filled with granules of ferric and aluminium oxide, also known as sacrificial material. It is this material which prevents the
molten material from trickling through and also acts as a cooling mechanism.

The core catcher device is installed at the bottom of a nuclear station’s protective shell to save the latter as well as prevent radioactive emission in case of a serious accident.

Usage of the device

It was first installed at Tianwan nuclear power plant in China in 2011. In 2018, a core catcher was installed at Rooppur 1 Nuclear Power plant in Bangladesh. At the Kundakulum plant it has been installed as per the site conditions and safety requirements. The device is well equipped with floor protection and has an improved seismic resitstance.