The proposed Jaitapur nuclear power plant in Ratnagiri district will be well shielded from water in case of natural disasters such as flood waves or tsunami.
The Nuclear Power Corporation of India Limited (NPCIL) is going to increase the height of the retention wall, which prevents the tidal waves from entering inland, to 10m, which is 2.5m taller than the stipulated height.
According to the Central Water and Power Research Station in Pune, the safe grade elevation for a retention wall – also called a water-break wall — around a nuclear plant must be 7.5m.
“The water-break wall is the first barrier for protecting the plant when there is turbulence in the water,” said CB Jain, project manager of the coastal plant. “Although the western coast does not have a tsunami threat, we have proposed to increase its height taking into account the worst case scenario.”
Taking lessons from the Japanese nuclear crisis in the aftermath of an earthquake and tsunami, Jain said the design for the European Pressurised Reactors (EPR) that would be used in the Jaitapur plant would be considered.
“Whatever feedback we get from Japan, the EPR design will be upgraded. But, in present condition, the EPR design is adequate,” said Jain.
The corporation will also make changes in the emergency standard procedures, a uniform written document on how a plant should be operated in crisis situation.
While the NPCIL has been getting reports from Japan, officials said it would take about four to six months for a detailed backward minute-to-minute account and
to carry out necessary upgrades.
Associate director, SP Dharne, said Indian nuclear plants were designed for earthquakes measuring between 5.5 and 6.7 on the Richter scale and could withstand ground shakes with 30% to 50% more intensity.
To calculate ground acceleration, experts first consider the seismic zone that the potential site falls under to get an idea on what sort of an earthquake to expect.
Officials then look at the 300-year history of earthquake in the form of documents. Based on the history, the Richter scale for the particular site is reconstructed along with potential destruction. Through standard mathematical calculations, a 100-year forecast is drawn up for the reactor and the location of the reactor is decided.