There have, of course, been new units added at the Kaiga and Tarapur nuclear plants in recent years, but Kudankulam is the first at a fresh site; its reactors of 1,000 MW each are also much bigger in comparison.
This is also the first pressurised water reactor to come up in India - with imported technology; others use the indigenous pressurised heavy water reactor (PHWR) technology.
Embroiled in much controversy, the fate of the plant was uncertain until recently.
What has changed, tilting the scales decisively in favour of the project is Tamil Nadu Chief Minister J. Jayalalithaa's position on the issue: opposed to it earlier, she now supports it. Her immediate priority appears to be addressing the power crisis in the state than pleasing anti-nuke activists.
The local protest against the plant continues, with one of its leaders even starting an indefinite hunger strike immediately after Jayalalithaa's volte face, but this is unlikely to prevent the plant's commissioning.
Kudankulam will also be the first nuclear project to start after the Fukushima Daiichi nuclear plant's meltdown in Japan in March last year, which reopened the global debate on nuclear safety.
The Nuclear Power Corporation of India, whose various plants currently generate 4,780 MW, has so far spent Rs 13,200 crore on the Kudankulam project.
Had it begun generating power, according to its original schedule, Tamil Nadu would have already got its share of 12 million units of electricity daily, or half the plant's production. But it is running six months late, and even in a best case scenario, will take at least another five months to start.
The second 1,000 MW unit should shape up by early 2013. The 3,000-acre site has provision for four more units of similar capacity, and Kudankulam will become India's largest nuclear power complex once the remaining units go critical.
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"We will be using enriched uranium to run the plant. The Russian Federation countries will supply us the fuel throughout the plant's life," says R.S. Sundar, station director at the plant.
By the summer of 2013, Tamil Nadu's share from the project is expected to go up to 1,000 MW, meeting the power needs of four million consumers.
Other nuclear plants currently operating have a lifespan of 30 to 35 years extendable by another 10. But the Kudankulam plant promises a lifespan of 40 years, extendable by another 20, and that is why it will be able to supply power at about Rs 2.50 per unit.
With shortage of coal and natural gas crippling power generation in India, the country is now going in for nuclear plants of high capacities. Two PHWR units of 700 MW capacity each are being built in Rajasthan and Gujarat.