Speaking to Press Trust of India over the phone, Sundar said power production is expected to resume in the next two or three days after the problem is fixed.

"The power generation from KNPP’s first unit stopped at 12.41 pm today as the reactor stopped functioning while we were carrying out some checks," Sundar added.

The unit, which was considerably contributing to Tamil Nadu’s power needs, since October 2013, was generating 400MWe of power before the reactor stopped functioning, according to the site director.

Located in the Tirunelveli district of Tamil Nadu, the Kudankulam NPP is scheduled to supply electricity to both Tamil Nadu, and the entire south India.

The unit 1 reached critical condition in July 2013, while the construction of the second power unit is nearing completion, according to the news agency.