Power Unit No. 5 of the Kudankulam NPP constructed in India under the Russian WWER-1000 reactor-type NPP design saw the first component of the nuclear reactor core melt localisation device (CMLD, core catcher), 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 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 localization pit, an embedded part was installed in the pit, and the reactor cavity was concreted from elevation point +1.700 to elevation point +6.300. Direct catcher installation work started after a permit from the Indian regulator had been obtained.

‘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’, intimated Mikhail Novikov, Director of Indian Projects, Atomstroyexport JSC. ‘Such moments vividly display the results of our activities and the progress of the Kudankulam NPP construction’.

The Power Unit 5 core catcher was delivered by the Russian Party to the Kudankulam NPP by a cargo vessel in January 2023.

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.