The Kudankulam Nuclear Power Plant (KKNPP) is the single largest nuclear power station in India, an institution for power generation located in the Tirunelveli district of Tamil Nadu. Its origin traces back to an Indo-Soviet agreement signed on November 20, 1988, between Prime Minister Rajiv Gandhi and Soviet leader Mikhail Gorbachev. The project was stalled after the collapse of the Soviet Union but was revived through a supplementary agreement in 1998 with the Russian Federation. Construction on the first unit began on March 31, 2002, with the purpose of expanding India's nuclear energy capacity to meet its growing energy demands.
The plant is a joint effort between the Nuclear Power Corporation of India Limited (NPCIL), which owns and operates it, and Russia's Atomstroyexport. KKNPP utilizes Russian-designed VVER-1000/V-412 model Pressurized Water Reactors (PWRs), which are distinct from India's indigenous Pressurised Heavy Water Reactors (PHWRs) as they use imported enriched uranium. Each reactor unit has a gross electrical capacity of 1,000 MW. Units 1 and 2 are currently operational, having been commissioned on October 22, 2013, and October 15, 2016, respectively, giving the plant a current operational capacity of 2,000 MW.
The KKNPP connects to the NPCIL, the Department of Atomic Energy (DAE), and the Atomic Energy Regulatory Board (AERB), which provides regulatory clearances. The plant is undergoing significant expansion, with Units 3, 4, 5, and 6 currently under construction, which will bring the total planned capacity to 6,000 MW. Construction for Units 3 and 4 began on June 29, 2017, and for Units 5 and 6 on June 29, 2021. A recent development was the commencement of 'Spillage to Open Reactor' for Unit 3 on April 25, 2026, a crucial milestone involving the flushing of safety systems in preparation for commissioning.