The Rajasthan Atomic Power Project’s Unit-7 (RAPP-7), a 700 MW Pressurized Heavy Water Reactor (PHWR) located in Rawatbhata, Rajasthan, achieved criticality on September 19, 2024, at 9:42 PM. Criticality refers to the point at which a nuclear reactor begins a stable, controlled chain reaction of nuclear fission, marking a key milestone in the reactor’s transition from construction to operation.
RAPP-7 is the third of sixteen reactors being constructed in India, part of the country’s effort to expand its nuclear energy capacity. The reactor’s criticality was approved by the Atomic Energy Regulatory Board (AERB) on September 10, 2024, following assessments of its design, construction, and operational readiness. This approval allowed for the controlled addition of heavy water to the reactor’s system and the initiation of a controlled fission reaction, leading to low-power physics experiments.
The reactor is operated by the Nuclear Power Corporation of India Limited (NPCIL), which manages 24 reactors across seven power plants with a total capacity of 8,180 MW. In addition to RAPP-7, eight reactors are currently under construction, projected to add another 6,800 MW to India’s energy grid. RAPP-8, located at the same site, is expected to begin operations in 2025, with a combined capacity of 1,400 MW between the two units.
Nuclear power, as a zero-emission energy source, supports the country’s goal of generating 500 gigawatts of non-fossil fuel energy by 2030. This program aims to reduce consumers’ reliance on coal and other fossil fuels, contributing to its environmental targets.
Ten additional reactors are in the planning stages, with completion targeted by 2031-32. The criticality of RAPP-7 marks an important step in India’s strategy to increase domestic power generation and enhance its energy security.