‘Kudankulam N-plant equipped to deal with tsunami threats'

The Nuclear Power Corporation of India Ltd has ruled out the probability of the calamitous events at the quake and tsunami-ravaged Fukushima nuclear power plant getting replicated at the Kudankulam Nuclear Power Plant (KKNPP) in Tirunelveli district of Tamil Nadu, not far from here.

This is despite the fact that the two plants, situated half-a-world apart from each other, share the same topographical features and look out into the sea, say NPCIL experts who took part in an awareness seminar here.

‘CORE MELT CATCHER'

They chose to hit the nail head saying that the KKNPP is equipped with a ‘core melt catcher' to deal with the most-feared but equally rare event of a ‘core melt.'

The KKNPP is also largely insulated from the danger of a ‘hydrogen explosion' that seems to have occurred at Fukushima, the experts said.

To convert any hydrogen forming in this unlikely event, passive hydrogen re-combiners are provided for to process the hydrogen back to water.

This precludes the possibility of accumulation of explosive quantity of hydrogen in the containment.

Thus the probability of the events at Fukushima getting replicated at KKNPP is next to nothing, experts said.

The reactors here are designed to be safe in all natural eventualities, such as tsunami and earthquake.

‘HOT RUN' SOON

The system circuits were recently hydro-tested and the results certified and accepted by Indian and Russian specialists as well as the Atomic Energy Regulatory Board of India.

Unit-1 of KKNPP is being readied for a ‘hot run' in a couple of days, when the safety systems will be tested for its design capability during operation.

The NPCIL experts were here to take part in an awareness seminar conducted jointly by the Kerala State Centre of The Institution of Engineers (India) (IEI), the Nodal Centre of Safety and Quality Forum of IEI Kerala, and the National Safety Council. The seminar on ‘Nuclear power reactors - safety aspects and challenges' was held at the Visvesvaraya Bhavan here last Wednesday.

The crisis at the Fukushima had created a world-wide scare about the safety aspects of sea-shore based nuclear power stations.

The KKNPP is one such and expected to go critical soon, said Mr S. Radhakrishnan, Chairman, Kerala State Centre of the IEI.

OPERATIONAL SAFETY

The technical seminar was spread in two sessions. The first session on ‘Safety of nuclear power plants and the recent Japanese experience' was led by Dr B. K. S. Nair, former head, Technical Services of the Department of Atomic Energy.

The second session on ‘Safety aspects of Kudankulam Power Project' was led by Mr Kasinath Balaji, Site Director, KKNPP, and his team.

According to them, the buildings that house the reactor and its auxiliary equipment, reactor safety systems, safety diesel generators and control room and other power generating equipment are all designed to operate safely under seismic activity.

This is despite the fact that Kudankulam falls within ‘Zone 2' representing ‘low damage risk' as per the latest seismic zoning map of India.

All buildings at the facility have been designed to rise from 7.5 m (about 25 ft) above the mean sea level (MSL) to preclude flooding due to any reason whatsoever, including tsunami. These design features got tested and validated during the tsunami event of year 2004. The Kudankulam site has also been provided with a shore protection bund rising to a height of 7.5 m above MSL.

The reactors boast ultra-modern ‘Gen 3+' safety design features in terms of the various passive safety systems backing up the active safety systems.

A number of safety systems are in place to ensure that the reactor core is always filled with boron-treated water and its temperature is kept well below the limits.

Twelve huge capacity water accumulators placed inside the reactor building ensure enough supplies.

In the event of a power supplies to the recirculation pumps tripping, the large-capacity steam generators kept at higher elevation will help cool the reactor through natural circulation.

COOLANT PUMPS

The steam generator water is cooled by a passive air cooling system, which works on the principle of natural convection and needs no external power supply.

This ensures long-term cooling of reactor core in the unlikely event of a lack of power supply to the coolant pumps.

Each reactor is provided with four redundant diesel generators, of which only one is required to keep it in ‘cold state' under ‘shutdown' condition.

The diesel generators at KKNPP are located at higher elevation of about 9 m (30ft) above MSL, which help isolate themselves from tsunami-like floods.

The cooling water pumps for the diesel generators are also kept in secured buildings, capable of withstanding earthquakes.

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