'DNA' investigations: Kudankulam’s lurking dangers

While the prime minister (PM) accuses NGOs funded from abroad of trying to sabotage the ‘state-of-the-art’ Kudankulam nuclear power plant (KKNPP), various studies carried out by government agencies as well as experts suggest that the site is unsafe for a nuclear project.

The studies reveal potential threats to the nuclear reactor campus from near-shore tsunami, volcanic eruptions, and Karst (vulnerable landscape). DNA has a copy of the reports submitted by the agencies and experts.

A 15-member expert group set up by the Centre cleared the project. “The Kudankulam site is located far off (about 1,500km) from the tsunamigenic fault [where tsunamis originate]. Thus a tsunami would take time and lose some of its energy by the time it strikes Kudankulam,” according to the group’s official document.

However, a 1982 study reported in a noted journal documents the presence of two slumps — the East Comorin and Colombo — in the vicinity of the site. A ‘slump’ is a massive agglomeration of loosely-bound sediment on the sea bed that may suffer large submarine landslides, causing mega-tsunamis.

The expert group’s first report failed to identify the presence of a slump that is about 100km from the plant. After activists brought it to the group’s notice, its second report noted the presence of the slumps and the possibility of a near-field tsunami.

“This is against their earlier position and to that of the Atomic Energy Regulatory Board (AERB) which said near-field tsunamis are not possible at the KNPP site,” People’s Movement Against Nuclear Energy (PMANE) functionary M Pushparayan said.

“It is suggested that large submarine landslides can generate a tsunami and may cause coastal hazard. An attempt has been made to quantify the amount of possible water displacement from the above slump belts in the Gulf of Mannar that may occur during a worst case scenario,” the expert group’s second report said. However, it added that the amount of water displacement will be too small to produce a serious tsunami.

A tsunami hazard study for all reactors on the coast was conducted across the world after the Fukushima disaster in Japan in March 2011. One such study has been attempted for the Kalpakkam nuclear plant site in Tamil Nadu. “However, no such study has been undertaken for KNPP,” Pushparayan said.

The Nuclear Power Corporation of India Limited, too, in an official response to DNA, said it was aware of both slumps and had factored them in. “After ONGC discovered these slumps, scientists from AERB and NPCIL held discussions with ONGC for understanding their implications,” it said.

NPCIL officials said the KNPP site has hard rock at reasonable depth providing good foundation. However, PMANE’s experts say a ground magnetic survey conducted in the area in 2010 showed that the thickness of the rock beneath the reactor was about 4,000 metres, as against the usual 40,000 metres. The crust is the layer of earth between the surface and the mantle.

Another report by A Bhoominathan, professor at the Indian Institute of Technology, Madras, said studies done to verify the suitability of the site had failed to identify weak zones. “Confirmatory geological and geotechnical investigations carried out after excavation of strata to the founding level at various sites for nuclear facilities show the presence of weaker zones which have not (been) identified in the original investigation,” his report said.

“The establishment had to spend a lot of time and money when they found these weak spots in 2001,” said PMANE member VT Padmanabhan. “They excavated these spots and tried to strengthen them by cement grouting. Yet it is not safe to have a nuclear power plant on a rock mass that has been cement-grouted.”

With regard to the possibility of volcanic eruptions in the area, the government’s expert group said no active volcanism had been identified. Samples of rocks collected from Abhishekapati, 50km away, after a minor volcanic eruption in 1998, however, raise questions about the region’s stability.

“The seismic tremors and tectonics in this region also raise a question of stability for the area,” said a report submitted in 2002 by the Tamil University’s department of earth sciences. Lava rock samples were sent for analysis to the department. “Before going for any major structure in Kudankulam, one has to ensure the tectonics of this block,” the report said. “It is lying on a lineament plane. So, it is a must to take up micro-level studies for confirming the tectonic stability of this landmass before launching a major plant in Kudankulam.”

However, the Centre’s expert panel denied this, saying the lava rock was “related to an electrical phenomenon which is seen even today as visible burnt and melt marks on the two electrical poles in Pondicherry based on samples collected 14 years after the event”. Hence, the reported rock melts are no indicators of underground volcanic activity, it felt.

Lastly, the formation of a sill hole at Punnayurkulam after the rain on November 26, 2011, and the occurrence of a similar incident three years ago at Radhapuram, both barely 10km from the plant, suggest that this area might be a Karst region. Karst is a special landscape that is formed by the dissolution of soluble rocks. It is among landscape most vulnerable to natural hazards.

“Extensive studies to understand these events should have been undertaken by NPCIL, but it remains unaware of these events,” said Dr R Ramesh, who has been working to identify the geology of the KNPP site since 2000. According to AERB guidelines, “in case, the potential of such geological hazards exists and no practical engineering solutions are available to mitigate their effects, the site is deemed unsuitable”.

“The Preliminary Safety Analysis Report (PSAR) for the KNPP prepared by the Russians and submitted to the AERB had no idea about all this. This is because the PSAR was completed in the last months of 1998 and submitted to the AERB in early 1999. Since 1998, a series of geological events have occurred in places near the Kudankulam site, and a thorough study should have been done,” he said.