"The turbine of the first unit has developed some problem. It seems some component inside the turbine turned loose and damaged the turbine blades," the source said preferring anonymity on Monday.

According to him, discussions are on with the experts whether to replace the faulty equipment from the turbine of the second unit so that the first unit could be run at the earliest.

The first unit stopped operations on 29th September due to turbine problem. The unit was shut down for maintenance in July this year and was restarted in September.

However, senior officials of Nuclear Power Corporation of India Ltd (NPCIL) were not available for clarifications. G.Sundarrajan, an anti-nulcear power activist who has filed a case against KNPP in the Supreme Court questioning the safety, said: "Even before starting its commercial operations the world class third generation plant is on the blink."

India's atomic power plant operator NPCIL is setting up two 1,000 MW Russian reactors at Kudankulam in Tirunelveli district, 650 km from Chennai.

The total outlay for the project is over Rs.17,000 crore. The KNPP is India's first pressurized water reactor belonging to the light water reactor category.

The first unit attained criticality in July 2013, which is the beginning of the fission process. The unit has started power generation and has been connected to the southern grid.

Work on commissioning the second unit is in progress. The unit is expected to start the fission process next month.

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