Chennai, Sep 2 (IANS): The Nuclear Power Corporation of India Ltd (NPCIL) has begun the process to restart the first 1,000 MW unit at its Kudankulam Nuclear Power Project (KNPP) following the sectoral regulator's permission, said a senior official.

"We have got AERB's (Atomic Energy Regulatory Board) permission to restart the unit Sunday. The process of restarting the unit is on," R.S. Sundar, site director, KNPP told IANS over phone Tuesday.

He said following the restarting of the unit, it has to increase the power levels and synchronise with the grid.

According to him, it would take around a week for the unit to operate at its full capacity.

The unit was shut down for annual maintenance in mid-July this year.

Sundar is hopeful of the unit going commercial this month but said it is for the head office to decide on that.

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.

As on July 2014, the physical progress of the unit stands at 99.95 percent.

The second 1,000 MW unit is expected to start commercial operations in March 2015, a date which is under review.

The physical progress of the unit stands at 97.44 percent as on July 2014.