800-tonnne core catcher, a critical safety device, installed at reactor 5 of KKNPP

The under-construction reactor 5 of Kudankulam Nuclear Power Project crossed a major milestone on Thursday as core catcher of the reactor, the most critical safety equipment, was placed in its position, amid wild cheers from Indian and Russian experts. Tirunelveli

The under-construction reactor 5 of Kudankulam Nuclear Power Project crossed a major milestone on Thursday as core catcher of the reactor, the most critical safety equipment, was placed in its position, amid wild cheers from Indian and Russian experts.

The core catcher, also known as nuclear reactor core melt localisation device (CMLD), is an essential part of the prevention system ensuring safety from beyond-design-basis accidents. The core catcher installed on supports under the reactor vessel is made as a globe-bottom container that weighs more than 156 tonnes. The total weight of the entire device exceeds 800 tonnes. 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 localisation pit, an embedded part was installed in the pit, and the reactor cavity was concreted. The core catcher installation work was started after due permission from the Atomic Energy Regulatory Board.

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

“Such moments vividly display the results of our activities and the progress of Kudankulam Nuclear Power Project (KKNPP) construction,” he added.

The core catcher was delivered by Russia to the KKNPP site by a cargo vessel in January. The core melt localisation device is a Russian invention, which is 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 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 the people. The core catcher installation is one of the critical path activities in the schedule and its completion makes it possible to construct the reactor cavity further.