Question 500Steam Plants - Assistant Engineer

The correct answer is C) Secure the fuel to the burners. In the event of a major flareback to a boiler, the immediate priority is to cut off the fuel supply to the burners. This action will stop the flow of fuel and prevent further escalation of the flareback, which could potentially lead to a boiler explosion or fire. Securing the fuel to the burners is the most critical step to mitigate the emergency situation. The other options are not the correct immediate actions. Securing the ventilation (A) or the forced draft fan (B) would not address the root cause of the flareback, which is the continued supply of fuel. Purging the fuel oil system (D) may be a subsequent step, but it is not the first priority during the emergency.