NTPC has formed a committee to find out the reason behind the explosion in a boiler at its Unchahar power plant unit, which has led to the death of 32 people till now. Gurdeep Singh, chairman and managing director, NTPC, told reporters in New Delhi on Friday that the committee, headed by SK Roy, executive director, operations, will probe the incident and submit a report in a month. The committee would try to figure out how the incidence took place, even as the safety mechanism was working as planned. Personnel from BHEL—the company which designed, manufactured and commissioned the power plant —have reached the site to review the situation.
NTPC runs 46 such units, the majority of which have been constructed by BHEL, without any major complain.
Singh said that while workers were trying to poke and remove the ash accumulated at the bottom of the boiler, it was observed that the pressure inside had gone up. The protection mechanism made the system trip after the pressure rose beyond a certain threshold inside the boiler, as per the design. The question now at hand is — how did the pressure continue to rise and open up the economiser section? The economiser unit uses the excess heat of the flue gases inside the boiler to heat the water, reducing the energy requirement. Opening up of the economiser led to the release of extremely hot air, gas and ash content in the surrounding area, leading to fatalities and injuries. Casualties increased because people working in the vicinity were blinded by the ash that came out of the economiser. The economiser unit needs to be replaced completely while NTPC hopes that the remaining parts of the 500-MW unit can be repaired.
Discussions are being carried on with BHEL on how soon normalcy can be restored in the unit. Though it is difficult to predict a precise timeline, the company said that it hopes the span would be three to six months. When asked about the potential effect of the incidence on NTPC’s finances, Singh said that “it is too early to determine the total cost incurred”. Refuting allegations that the boiler was put in production in a hurry, Singh said that the commercial operation date (COD) was actually delayed by three months to September to ascertain that all checks and verification were diligently completed. He added that NTPC regularly conducts regional operations performance review to make sure all operational safety standards at all its plants are up to the mark.
Apart from NTPC employees, various other leftover works such as cleaning, painting and cladding of insulators were being carried out by BHEL sub-contractors on that fateful day.