NPCIL Achieves Commissioning Milestone at Kudankulam Nuclear Power Project Unit-3

In a statement on Monday, NPCIL said, "A significant stride in India's journey towards energy security and sustainability! Nuclear Power Corporation of India Limited (NPCIL) has achieved a major commissioning milestone at Kudankulam Nuclear Power Project, Unit-3 with the successful commencement of 'Spillage to Open Reactor' on 25 April 2026."

The Kudankulam Nuclear Power Plant Unit-3 has inched closer to commissioning with the start of 'Spillage to Open Reactor', a crucial step in preparing reactor systems, Nuclear Power Corporation of India Limited (NPCIL) said.

The term 'Spillage to Open Reactor' refers to the use of water to flush and clean the reactor's coolant systems and pipelines in preparation for safe operation.

The company said the activity is a crucial step in preparing the reactor systems for operation. "This critical activity ensures flushing and conditioning of safety systems and main coolant pipelines using light water, establishing the required cleanliness for advanced commissioning stages. It marks the start of individual functional testing of primary system equipment, a decisive step towards bringing Unit-3 closer to operation," the statement said.

The milestone was inaugurated by NPCIL Chairman and Managing Director B C Pathak in the presence of Mikhail Novikov of Atomstroyexport, underlining ongoing India-Russia cooperation in the nuclear sector.

Located in Tamil Nadu's Tirunelveli district, the Kudankulam project is central to India's clean energy plans. NPCIL had previously said Units 1 and 2 have already generated more than 121 billion units of electricity, preventing nearly 104 million tonnes of carbon dioxide emissions. Once all six units are completed, the site will have a total installed capacity of 6,000 MW.

NPCIL said it "remains committed to the highest standards of safety, quality, and environmental stewardship, powering a cleaner, stronger, self-reliant India."

India's civil nuclear partnership with Russia continues to play a key role in expanding capacity. Earlier, in March, External Affairs Minister S Jaishankar had highlighted Moscow's role in India's nuclear programme while speaking at the "India and Russia: Towards a new bilateral agenda" conference. He said, "Russia is our foremost partner in civil nuclear energy and the Kudankulam nuclear project is a stellar example. As India aims to increase its nuclear energy generation capacity to 100 gigawatt by 2047, I am confident that it will find a trusted and reliable partner in Russia for peaceful uses of nuclear energy."

The issue was also discussed during Russian President Vladimir Putin's visit to India in December last year. In a joint statement after the 23rd India-Russia Annual Summit with Prime Minister Narendra Modi, both sides agreed to deepen cooperation in nuclear energy, including fuel cycles, localisation, and joint manufacturing of equipment.

Putin said, "We're conducting a flagship project to build the largest Indian nuclear power plant, Kudankulam. Two out of six reactor units have already been connected to the energy network, and four are still under construction. Getting this nuclear power plant to full power output will make an impressive contribution to the energy requirements of India."

The two sides also agreed to speed up discussions on setting up a second nuclear power plant site in India and expand cooperation in peaceful uses of atomic energy, in line with India's target of achieving 100 GW of nuclear power capacity by 2047.

India has also made progress in indigenous nuclear technology. Recently, the Prototype Fast Breeder Reactor at Kalpakkam in Tamil Nadu achieved first criticality, a major step in reactor operations. In his 'Mann Ki Baat' address, Prime Minister Modi said, "A few days back, our Nuclear Scientists brought glory to India through a major achievement. In Tamil Nadu's Kalpakkam, the Fast Breeder Reactor has achieved Criticality. This is a stage in which the reactor achieves success in a self-sustaining nuclear reaction for the first time. The stage means the beginning of the reactor's operation phase."

He added, "This is a historic milestone in India's nuclear energy journey. And the big thing is that this nuclear reactor is built with entirely indigenous technology. I congratulate all those who have made invaluable contributions to India's nuclear program. Their efforts to make the lives of countrymen better and easier are really commendable. This will give new energy to our resolve of Viksit Bharat."