Even as a debate rages over the safety and future of nuclear power plants in the wake of the devastating earthquake and tsunami that triggered a nuclear crisis in Japan and raised concerns the world over, the Nuclear Power Corporation of India Limited (NPCIL) on Monday said Indian nuclear plants have remained safe during two natural calamities in the last decade but there was no room for complacency.

“We cannot be complacent and therefore we are closely observing the experiences of the rarest event that is taking place in Japan where nuclear plants in the Northeast part are affected following the severe and devastating earthquake and tsunami,’’ NPCIL said, in a statement, adding that it was monitoring all the developments in Japan.

It further stated that despite a major earthquake in Bhuj on January 26, 2001, the Kakrapar Atomic Power Station near Surat in Gujarat continued to operate safely. Similarly, during the tsunami in Tamil Nadu in December 2004, the Madras Atomic Power Station (MAPS) was safely shut down without any radiological consequences. The plant was restarted in a matter of days after regulatory review, it added.

The Koodankulam Nuclear Power Plant (KKNPP) in Tamil Nadu, where two new reactors of 1000 MW capacity each are under construction, also remained unaffected by the Tsunami because of the higher than sea-level site of the plant. It said all the 20 operating plants of NPCIL undergo periodical safety review and upgradation of required safety features with clearance from the Atomic Energy Regulatory Board.

NPCIL currently operates 20 reactors with installed capacity of 4780 MW. Of these, two are Boiling Water Reactors (BWRs) of 160 MW each (units 1 and 2), while others are Pressurised Heavy Water Reactors (PHWRs). The safety of these BWR plants was reanalysed a few years ago and was reviewed further by Atomic Energy Regulatory Board (AERB).

Following this, the two BWRs at TAPS-1&2 have been renovated, and upgraded with additional safety features to meet the latest safety standards, NPCIL said.

The PHWRs are of different design than BWRs and have multiple, redundant and diverse shutdown systems as well as cooling water systems. It said an in-depth review of events such as the earthquake and tsunami have been made for all the plants and necessary reinforcement features based on the outcome of these reviews have been incorporated.

It said the developments in Japan will be reviewed in detail in due course as the detailed information becomes available. NPCIL is gathering information from various agencies such as the World Association of Nuclear Operators (WANO), International Atomic Energy Agency (IAEA) and Tokyo Electric Power Company (TEPCO) in this regard, the statement added.