An internal report from NTPC said an “error in judgment” by plant operators led to an explosion at India’s Feroze Gandhi Unchahar Thermal Power Station last year that resulted in the deaths of 45 workers.
Reuters news service on July 23 said it had reviewed a summary of the report on the accident that occurred November 1, 2017. It said three department heads at the 1,550-MW coal-fired plant decided not to shut down a 500-MW boiler at the plant to clear ash that had built up in the unit. The buildup caused the unit to over-pressurize, which caused an explosion that released hot gas, killing several workers instantly. Others died in the days after the accident, which left survivors with severe burns.
India’s Power Ministry in the week after the accident established a committee to investigate the explosion.
Asian News International in November, in a post on its Facebook page, presented a video taken by a worker using a mobile phone after the accident.
Operators Were Experienced
Reuters said the department heads each had 28 years’ experience. It said they were responsible for the plant’s operation, ash handling maintenance, and boiler maintenance. All three reportedly died in the accident.
The Unchahar plant Uttar Pradesh state supplies electricity to nine states—Uttar Pradesh, Haryana, Himachal Pradesh, Jammu and Kashmir, Punjab, Rajasthan, Chandigarh, Delhi, and Uttarakhand—and employed about 870 workers at the time of the accident. The explosion occurred in a unit of the plant that was commissioned in March 2017 and had been operating on a trial basis for about two months before the accident.
Reuters reported that two NTPC officials, who wanted to remain anonymous citing government policy, told the news service the company did not have equipment at the plant that could measure ash buildup and instead relied on physical inspection of the boilers.
According to Reuters, the report said the plant’s operators reduced the unit’s load when they became aware of the ash buildup and as workers began clearing the ash from the bottom of the furnace. But the buildup caused a boiler tube carrying steam to leak, and a buildup of steam pressure in the unit caused it to “trip,” or shut down, Reuters reported. Hot ash and gas were released at high speeds, killing and injuring workers.
The report summary said, “The shut down of the boiler much before the incident would have been prudent.” Reuters said the report was prepared by an internal NTPC group and it was not clear from the summary when the report was submitted for review.
Full Report Still Not Released
Reuters said NTPC, which is India’s largest power generator, has not released the full report and has not commented on its details. Reuters said Bharat Heavy Electricals Ltd., which manufactured the boiler tubes at the Unchahar plant, had not responded to requests for comment.
The news service said a spokeswoman for NTPC in an email said the company is conducting regular safety audits and mock drills in response to the accident and has revised its safety policy. Other utilities in India also announced a review of their safety measures in the wake of the accident.
The death toll from the explosion is the highest from a power-plant accident in recent years. An explosion at a hydropower station in Siberia in 2009 left 75 people dead. There were 74 deaths reported in November 2016 from the collapse of a platform at a coal-fired power plant under construction in China.
Indian officials said the Unchahar explosion is the worst industrial accident in that country since 45 people died when a chimney collapsed during construction at Bharat Aluminum Co.’s Korba thermal plant project in 2009.
—Darrell Proctor is a POWER associate editor (@DarrellProctor1, @POWERmagazine).