The Nuclear Power Corporation of India Limited (NPCIL) has stated that the European Pressurised Reactor (EPR) reactor planned at the Jaitapur nuclear power plant in Maharashtra meets the highest safety requirements of the world’s leading regulatory authorities and offers in-depth protection against both external and internal accidents.
In a statement issued here, NPCIL said the Fukushima accident in Japan has revived the debate on nuclear energy and raised questions about the safety of nuclear power plants and their ability to withstand extraordinary events.
“As an evolutionary design, the EPR reactor planned at Jaitapur combines proven safety systems inherited from its highly efficient parent reactors, the French N4 and the German Konvoi, which total more than a hundred years of safe and effective operation and have generated over 1,160 TWh of electricity so far, and incorporates innovative features that integrate the return on experience from past industry events,’’ the statement said.
The statement further said the EPR reactor meets the highest safety requirements of the world’s leading regulatory authorities and offers in-depth protection against both external and internal accidents. “It is not accurate to compare the seismic risks of different countries as they are not using the same scale and the same terminology to qualify the different seismic zones. Each country establishes its own categorisation,’’ it said.
What is seismic zone 1 in a particular country might be categorised as seismic zone 2 in another, depending on the natural geography of the country. “It is broadly agreed that India, and Jaitapur in particular, is in a significantly lower seismic zone than Japan and Fukushima. An earthquake of the same magnitude is thus more than unlikely to happen here,’’ he added.
It said the EPR reactor has been designed according to certain standards as well as the site-specific seismic data making it able to endure even more severe conditions that those ever registered on site. It said the most severe event ever observed at the closest fault located 64 km from Jaitapur site was the 1967 Koyna earthquake, which reached a 6.5 magnitude (3,000 times less powerful than the one that just occurred in Japan).
Preliminary studies have been carried out on the Jaitapur site and revealed that the Peak Ground Acceleration to be considered on site is well under the 0.25g the EPR is designed to withstand. The most important feature to ensure high seismic resistance of the EPR is that its main nuclear buildings are all on a unique large and thick concrete slab.
Also, snubbers or equivalent equipment are implemented to reduce vibrations. The reactor and its safety systems, the safety diesel generators, the fuel building and the control room would all remain under control and operate safely under seismic condition.
Furthermore, the average natural elevation of the Jataipur site being at 25 meters above the Mean Sea Level (MSL), the lowest site-point, after groundwork, is set to be at 10 meters above the MSL. This positions the plant way above the safe grade elevation calculated for the site and, therefore, naturally protects the plant from the impact of a tsunami. “If an earthquake should occur, control rods that stop the nuclear reaction would fall automatically into the core, shutting down the reactor while the cooling system would remove the residual heat,’’ the statement added.