The NPCIL said the commercial operation of the first unit is expected to start in May. The physical progress of the project is at 99.85 percent as of March 2014.
The second 1,000 MW unit at the Kudankulam Nuclear Power Project (KNPP) is expected to start commercial operations December 2014 and the physical progress of the project is at 97.03 percent as of March 2014.
In February, the NPCIL said the first unit would commence commercial operations in April 2014.
India's atomic power plant operator NPCIL is setting up two 1,000 MW Russian reactors at Kudankulam in Tirunelveli district, 650 km from here. The total outlay for the project is over Rs.17,000 crore.
The KNPP is India's first pressurised water reactor belonging to the light water reactor category.
The first unit attained criticality July 2013, which is the beginning of the fission process.
In August 2013, the Atomic Energy Regulatory Board (AERB) gave its permission to generate power up to 50 percent (500 MW) of the rated capacity. Subsequently, the regulator allowed the unit to generate power up to 75 percent capacity.
It is learnt NPCIL has applied to the AERB for permission to increase the power levels up to 90 percent.