The first approach to criticality in the second unit of the Kudankulam Nuclear Power Plant near here started at 7.52 PM today, KKNPP site director R S Sundar said.
The Atomic Energy Regulatory Board had already given its nod to the Nuclear Power Corporation of India (NPCIL), a PSU under the Department of Atomic Energy that operates the plant, to go ahead with the criticality process.
The reactor would attain criticality gradually during the next 48 hours, KKNPP sources said.
Unit 1 and 2 of the KKNPP VVER reactors are being built with the collaboration with Russia. Each reactor has the capacity to generate 1000 MW of electricity.
The first unit started generating power in October 2013. But the plant saw several breakdowns during its operation following which it had to be shut down for sometime to undertake repairs work.