Defying prohibitory orders, fishermen from Kanyakumari, Tuticorin and Tirunelveli districts came in boats with black flags hoisted atop them and laid siege about 500 metres from the plant.
They also did not venture into the sea to protest the government's move to commission the 1,000 MW Unit-I of the KNPP, an Indo-Russian joint venture.
The protest was planned to coincide with the second anniversary of the Fukushima nuclear disaster in Japan.
The protesters also raised slogans against the Centre and Tamil Nadu government and said the protests would be further intensified if the government went ahead with its decision to commission the KNPP.
S P Udhayakumar, convener of the Peoples Movement Against Nuclear Energy, which is spearheading the stir, said "the government seems to be stubborn in implementing the project. That is great injustice to Kudankulam people and fishermen."
He said while reports said excess sums were spent on the non-functioning nuclear project, the government was "foisting cases" on transfer of funds from abroad (for NGOs).
"At a time when our fishermen are being killed (allegedly by Lankan navy), the government has employed navy and air force to suppress our protest," he charged.
Alleging that national parties including Congress and the Bharatiya Janata Party, and Dravida Munnetra Kazhagam and All India Anna Dravida Munnetra Kazhagam in Tamil Nadu were playing politics on the issue, he said the project was using "outdated and unsafe technology."
The pact signed for the plant was also of no use in case of an accident, he claimed.
Tight security was made in the area with 4000 police personnel being deployed, police said.
Meanwhile, Tamil Nadu government reviewed the law and order situation in the wake of this protest besides those being held across the state by college students in connection with the Sri Lankan Tamils issue.
Tamil Nadu Chief Minister Jayalalithaa chaired a review meeting of top officials, including Chief Secretary Sheela Balakrishnan, Home Secretary R Rajagopal and DGP K Ramanujam, at Chennai.
Image: The Kudankulam Nuclear Power Project in Tamil Nadu
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