Question 269Steam Plants - 1st Asst/Chief

The correct answer is D) Secure the fuel to the burners. In the event of a major flareback to a boiler, the immediate action that should be taken is to secure the fuel supply to the burners. This is because a flareback is an uncontrolled ignition of fuel vapors, which can lead to a dangerous situation. By securing the fuel, the source of the problem is eliminated, preventing further flare-ups and potential damage to the boiler or the surrounding equipment. The other options are not the correct immediate actions to take. Purging the fuel oil system (A) or securing the forced draft fan (C) would not address the immediate risk of the flareback. Securing all fire room ventilation (B) could potentially worsen the situation by limiting the air supply, which could lead to incomplete combustion and further flare-ups.