Reactor pressure vessel installed at Indian nuclear plant

The pressure vessel, which was manufactured at the Atommash plant of Rosatom's Machine Building Division in Volgodonsk, in Russia, was delivered to the construction site in 2025. The installation was carried out using the "open top" method, using a heavy-duty crane to lift it into the building before the reactor dome is closed, the Russian company said. This method was previously used by the Russian-Indian team during the construction of Kudankulam units 3 and 4.

With the reactor vessel installed, the main equipment of the nuclear steam supply system - steam generators, main circulation pumps, main circulation pipeline units, pressure compensator, and emergency core cooling system tanks - can now be installed. 

“А recipe for the success of the Kudankulam NPP project is the long-standing and efficient cooperation between India and Russia. Indian specialists are constructing and commissioning four power units based on the Russian design, with two more power units generating electricity for over 10 years," Mikhail Novikov, Atomstroyexport Director of Projects in India said.

_{The vessel was lifted into place in a precision operation (Image: Rosatom)}

The Kudankulam nuclear power plant project is being implemented under an intergovernmental agreement between India and Russia dating back to 1988. The first two Russian-supplied VVER-1000 pressurised water reactors, which are owned and operated by the Nuclear Power Corporation of India Ltd (NPCIL), were connected to the Indian grid in 2013 and 2016, respectively. According to Rosatom, by April 2026 they had generated more than 127 billion kWh of electricity.

Four further VVERs are under construction: work started on the second phase of the Kudankulam project, units 3 and 4, in 2017, and on units 5 and 6 in 2021. Once all six units are in operation, Kudankulam's output will cover a significant share of the electricity demands in Tamil Nadu, a state of 72 million, as well as being distributed in other states on India's southern grid, according to Rosatom.

"The milestone reflects the strong collaboration and coordinated efforts between NPCIL and Atomstroyexport ... Kudankulam stands as a cornerstone of India’s clean energy ambitions. With Units 1 & 2 already generating power at rated capacity and having produced nearly 130 billion units of electricity, the project has already helped avoid approximately 112 million tonnes of CO₂ emissions -a significant contribution to environmental sustainability," NPCIL said.

A fourth phase comprising two VVER-1200 reactors - Kudankulam 7 and 8 - has been proposed.