The death toll in the boiler blast at state-run NTPC Ltd’s Unchahar power plant in Raebareli, Uttar Pradesh, has risen to 32, NTPC CMD Gurdeep Singh said on Friday.
The NTPC CMD said “a panel headed by executive director S.K. Roy looking into the cause of the accident, and will submit his report in a month.”
The 1,550 mega watt (MW) coal-fuelled plant (about 110km from state capital Lucknow) that supplies electricity to Uttar Pradesh, Haryana, Himachal Pradesh, Jammu and Kashmir, Punjab, Rajasthan, Chandigarh, Delhi and Uttarakhand has 840MW capacity available for generation.
“An unfortunate accident struck NTPC-Unchahar in the boiler of Unit #6 (500MW) yesterday…Twenty nine persons have succumbed to injuries and 85 are being treated at hospitals in Raebareli and Lucknow,” India’s largest power generation utility said in a statement on Thursday.
The Uttar Pradesh government has ordered an inquiry to determine within seven days the cause of the blast in the Unchahar plant. “Blockages in the flue gas pipe in a unit led to the blast. Hot fuel gases and steam let out by the blast severely injured several workers,” Sanjay Kumar Khatri, the top government official of Raebareli district where the plant is located, told Reuters on Thursday. “A magisterial inquiry has been initiated. This two-member technical team will submit findings within seven days,” Khatri said.
The National Human Rights Commission (NHRC) has served a notice to the Uttar Pradesh government over the death of more than 20 people in blast, an official said on Thursday evening.
The blast occurred in the boiler area of the recently commissioned 500MW unit. The equipment for the plant was supplied by state-run Bharat Heavy Electricals Ltd. “There was clinker formation that choked the bottom ash outlet,” said an NTPC executive requesting anonymity.
While boiler cleaning operations are automated, there are instances when it needs manual cleaning in the case of clinker formation. Clinkers are lumps formed after burning of coal at high temperature in the furnace. “With the clinkers choking the bottom ash outlet, the pressure in the boiler went up thereby melting the water valves surrounding the boiler. This created a vent, with hot flue gases and steam at high temperature escaping. This got mixed with ash (around 200°C) present and injured and killed the personnel present,” said the executive.
NTPC has set up an enquiry under executive director, operations, S.K. Roy to investigate the accident.
“Unit#6 (500MW) of the plant is under shutdown after the accident; however, the other units of the station are operating normally,” the NTPC statement added.
Of India’s installed power generation capacity of 329,298.27MW, NTPC projects account for 16%, or 51,635MW.
“It is a very uncommon incident. The economizer duct blew releasing flue gas and steam. There was a pressure buildup. Due to the impact, people who were working there were thrown back a distance of 10-20m,” said a second NTPC executive who also didn’t want to be named.
Experts believe that the incident points to a serious safety issue.
“There has either been instrumentation failure or compromise on operational safety,” said a former power ministry official requesting anonymity.
“One has not heard of major accidents in NTPC plants over the last 20 years. Investigations have to be done to find out why this has happened. I am very sure that NTPC would reinforce their safety standards and protocol in the light of findings of the enquiry committee,” said P. Uma Shankar, India’s former power secretary.
Power and new and renewable energy minister Raj Kumar Singh reached the plant site on Thursday morning, accompanied by Shrikant Sharma, UP’s energy minister. Congress vice-president Rahul Gandhi also met the injured who are admitted at the district hospital on Thursday morning. The constituency is important because it is represented by Congress chief Sonia Gandhi.
Meanwhile, the Union health ministry has arranged to treat some of the blast victims at All India Institute of Medical Sciences and Safdarjung Hospital trauma centres in New Delhi. “About nine patients are likely to be shifted there today (Thursday). The Union health minister is in regular contact with the state authorities,” the health ministry said in a statement.