Aaron Larson reports that coal-fired and gas-fired power plants are inherently dangerous. Nuclear power plants are not based on safety records ove rthe past 40 years. Although safety is taken very seriously at all such facilities, every year workers around the world are killed on the job by electrocution, falls, explosions, fires, and while working in confined spaces. Many more are injured through various less-extreme accidents.
On November 1, an explosion and fire at NTPC’s Feroze Gandhi Unchahar Thermal Power Station in India killed 43 people and injured many more. The incident investigation will take some time to complete, but an NTPC official reportedly said pressure inside the boiler reached 70 times normal operating pressure prior to the blast. An emergency shut-off mechanism apparently failed to actuate, causing the explosion, which resulted in pressurized steam and hot flue gases overwhelming dozens of workers. In another incident, this one on June 29 at the Big Bend Power Station in Apollo Beach, Florida, five workers were killed while trying to unplug a slag tank blockage under the plant’s Unit 2 boiler. The workers were water-blasting through a “doghouse door” while the unit was online. Local media sources reported that about 20 minutes into the job, molten slag, which can reach temperatures above 1,000F, burst through the door, burning the workers severely. Two died at the scene and three perished later as a result of their injuries.
For Larson, the news of those incidents brought back memories of near misses in my past. When he was the operations and maintenance manager at a biomass plant in the Midwest, our boiler experienced a significant wall tube rupture that blew the corner of the boiler apart, releasing high-pressure steam and flue gases into the boiler building. Fortunately, the incident occurred on the night shift when only a few operators were onsite. Although one worker had been in the area doing rounds roughly 30 minutes earlier, no one was in the immediate vicinity when the tube ruptured.
The burst was unexpected to say the least. The boiler was relatively new, having only been in service for perhaps a couple of years prior to the incident. The cause was sootblower erosion, which had resulted due to excessive settings being established during commissioning. Wall blowers on the two lowest levels of the furnace were being operated at higher-than-necessary pressures, on a more-often-than-required frequency, performing double sweeps during each actuation in an effort to keep wall tubes spotless. The commissioning contractor believed the extreme level of cleanliness was necessary in order to meet performance guarantees. However, the steam from the wall blowers was reaching the corner tubes, eroding them significantly and causing the premature failure.
Another incident from my past that could have been tragic if someone had been in the wrong place at the wrong time occurred when a boiler gauge glass burst. They didn’t have a good explanation for why it failed, but I can tell you that the noise near the boiler drum following the break could easily have been mistaken for a jumbo jet taking off. Larson personally isolated the gauge, using chain operators from two decks below. Fragments of glass speckled the wall some 25 feet away. Thankfully, no one was nearby when the burst occurred.
Larson's point is that risks abound throughout power plants, even in areas that workers may consider to be reasonably safe. In the military, recruits are often told to “Keep your head on a swivel.” It means to keep your eyes open and be keenly aware of everything that’s going on around you. Those words are worth remembering when a person is in a power plant. Workers must always pay attention to their surroundings and watch for potential danger lurking nearby. Never put yourself in the line of fire, but if necessary, be prepared to move at a moments notice ...and know where to go beforehand.