Officials said a total of 4,000 policemen had been deployed around the plant and a close vigil would be kept on movement of persons.
District collector Samayamurthy said he had banned assembly of more than four persons within this area
People's Movement Against Nuclear Energy has threatened to picket the plant on Monday.
The Indo-Russian project was scheduled for commissioning in December 2011 but has been delayed following protests by locals citing safety concerns.
The 1000 MW first unit of the project is expected to be commissioned soon.