Nuclear Power Corp to review all safety norms

Anil Sasi New Delhi | Updated on April 01, 2011

A file picture of Turbine Generator Erection at the Koodankulam plant.   -  THE HINDU

'A nuclear accident anywhere is a nuclear accident everywhere', is an oft-used aphorism in the nuclear business. The explosions and partial meltdown concerns playing out at Japan's Fukushima atomic power plant have cast a shadow over proposals for new nuclear reactors around the world.

India has joined a bevy of major nuclear nations, including China and even the US, which plan to reassess safety aspects of atomic projects in the wake of the events unfolding in Japan.

NPCIL (Nuclear Power Corporation of India Ltd) plans to comprehensively reassess safety aspects after carrying out a complete analysis of the Japanese incident, a senior official with the State-owned utility said. Besides, the nuclear regulator, the Atomic Energy Regulatory Board (AERB), plans to take a fresh look at beefing up emergency preparedness guidelines, especially for new imported reactors.

Indian nuclear operators are also in constant touch with the World Association of Nuclear Operators (WANO) in Tokyo and the International Atomic Energy Agency in Vienna for updates on the situation on a real-time basis.

Apart from safety design reviews by both equipment manufacturers and nuclear plant operators, the immediate impact could be in the form of insurance/reinsurance costs that are likely to skyrocket for new projects.

From NPCIL's point of view, the four new imported reactor design choices made by India offer safety features that considerably lower the chances of a repeat of a Japan-type incident.

Unlike the dated, 40-year-old Fukushima Daiichi plant which withstood the magnitude 9 earthquake but whose generators and backup systems were severely damaged in the ensuing tsunami, affecting their ability to cool the reactors, the safety features on the newer, third-generation units are much more robust.

French firm Areva's EPR reactor series and the Russian State-owned Rosatom's VVER reactors have core-catchers under the pressure vessel which allow collection and retention of the molten core should the reactor vessel fail in the unlikely event of a core melt.

The two American reactor designs - Toshiba-owned Westinghouse's AP1000 design and GE-Hitachi's ESBWR - have provisions for enhanced water cooling. The crisis at the Fukushima plants stemmed from the failure of the cooling systems in the reactors, leading to temperature and pressure build-up in the containment building in the station, prompting concerns of multiple meltdowns at two of the reactor units.

The Koodankulam power station, for instance, where two Russian VVER 1000 MWe units are in an advanced stage of construction, incorporates special devices that intercept, cool and localise core melt in case of an accident ? a kind of concrete trap situated under the reactor. Besides, the two structures, located on the Indian Ocean coast, survived the 2004 tsunami, the tidal waves being stopped by a special wave cutter.

The French EPRs, which are being considered for the Jaitapur site, promise an outer shell covering the reactor building that provides protection against a large commercial or military aircraft crash, apart from the provision for a 'core catcher'.

Besides, Indian sites fall in a much lower seismic activity range (maximum of zone three, except for Narora in zone four), as against zone five for Japanese sites such as Fukushima. The Fukushima reactors are BWR or boiling water reactors, the same as the two Tarapur units in India. Of the 20 operating reactors in India, 18 are Pressurised Heavy Water Reactors while there at the two BWRs at Tarapur.

Published on March 14, 2011

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