Critical safety equipment core catcher installed at Kudankulam nuclear plant

CHENNAI: The fifth 1,000 MW nuclear power plant being built by the Nuclear Power Corporation of India Ltd (NPCIL) at Tamil Nadu's Kudankulam reached a major milestone with the installation of the "core catcher".

According to Russia’s integrated nuclear power global major Rosatom, the first component of the nuclear reactor core melt localisation device (CMLD, core catcher) has been installed.

The core catcher is an essential part of the prevention system ensuring the safety of beyond-design-basis accidents, installed in the design position.

The core catcher installed on supports under the reactor vessel is made as a globe-bottom container that weighs more than 156 metric tons. The total weight of the entire device exceeds 800 metric tons.

Apart from a casing, the main CMLD components include: cartridge units filled with special non-metallic materials, maintenance platform, cantilever truss, and a bottom plate. As part of preparations for the device installation, a significant scope of work was completed, in particular, the second concrete layer and sealing liners were placed in the melt localisation pit, an embedded part was installed in the pit, and the reactor cavity was concreted.

Direct catcher installation work started after a permit from the Indian regulator had been obtained, Rosatom said.

“It brought us an exceptional pleasure when, during expert discussions currently taking place at the construction site, the Indian party invited all participants to come to a large window and to observe the catcher being raised before the installation,” said Mikhail Novikov, Director of Indian Projects, Atomstroyexport JSC.

The core catcher for Unit 5 was delivered to the NPCIL at Kudankulam in January. The core melt localisation device is a Russian invention, part of the passive safety system, it is intended to prevent radioactive substances from entering the environment in case of a severe accident followed by the reactor vessel destruction.

The core catcher is able to contain liquid and solid fragments of the core and structural materials of the reactor for an indefinitely long time, keeping a nuclear power plant safe for the environment and people.

The core catcher installation operation is one of the critical path activities in the schedule, the completion of which makes it possible to construct the reactor cavity further.

India's atomic power plant operator NPCIL has two 1,000 MW plants (Units 1 and 2) at Kudankulam, while four more (Units 3, 4, 5 and 6) are under construction. All the six units are built with Russian technology and equipment supplied by Rosatom.

Major equipment for building the third and fourth units have reached Kudankulam from Russia and a sizable number of components for the fifth and sixth units are to come.