An air infiltration abatement system for a power plant having a furnace, the air infiltration abatement system comprising: a recirculated flue gas source; a recirculated flue gas supply line connected to the recirculated flue gas source; a power plant component, the power plant component being a sootblower and having a leakage area in fluid communication with the recirculated flue gas supply line; wherein the recirculated flue gas source receives a combustion flue gas from the furnace and provides the combustion flue gas to the recirculated flue gas supply line, and the recirculated flue gas supply line supplies the combustion flue gas as a recirculated flue gas to the furnace via the leakage area of the power plant component; a seal box comprising a sleeve in fluid communication with the leakage area of the power plant component, wherein the recirculated flue gas is supplied to the furnace, via the leakage area of the power plant component, through the sleeve of the seal box; wherein the seal box surrounds a connection area wherein the sootblower passes through the sleeve and penetrates a wall of the furnace to provide a sootblowing steam to an interior space of the furnace, wherein the recirculated flue gas displaces other gases in the connection area; and a pressure regulating part located in the recirculated flue gas supply line and including a seal gas fan, a pressure sensor, and a pressure regulating valve disposed therebetween, wherein the pressure sensor provides a signal to the pressure regulating valve, and the pressure regulating valve regulates a pressure of the recirculated flue gas based on the signal, the pressure regulating part effectively controlling the pressure of the recirculated flue gas at the pressure sensor such that a downstream pressure in the seal box is greater than a pressure in the interior space, wherein the pressure regulating part maintains a pressure differential between the downstream pressure and the pressure in the interior space at a value which effectively prevents the other gases from flowing into the interior space while minimizing power requirements of the seal gas fan. a recirculated flue gas source; a recirculated flue gas supply line connected to the recirculated flue gas source; a power plant component, the power plant component being a sootblower and having a leakage area in fluid communication with the recirculated flue gas supply line; wherein the recirculated flue gas source receives a combustion flue gas from the furnace and provides the combustion flue gas to the recirculated flue gas supply line, and the recirculated flue gas supply line supplies the combustion flue gas as a recirculated flue gas to the furnace via the leakage area of the power plant component; a seal box comprising a sleeve in fluid communication with the leakage area of the power plant component, wherein the recirculated flue gas is supplied to the furnace, via the leakage area of the power plant component, through the sleeve of the seal box; wherein the seal box surrounds a connection area wherein the sootblower passes through the sleeve and penetrates a wall of the furnace to provide a sootblowing steam to an interior space of the furnace, wherein the recirculated flue gas displaces other gases in the connection area; and a pressure regulating part located in the recirculated flue gas supply line and including a seal gas fan, a pressure sensor, and a pressure regulating valve disposed therebetween, wherein the pressure sensor provides a signal to the pressure regulating valve, and the pressure regulating valve regulates a pressure of the recirculated flue gas based on the signal, the pressure regulating part effectively controlling the pressure of the recirculated flue gas at the pressure sensor such that a downstream pressure in the seal box is greater than a pressure in the interior space, wherein the pressure regulating part maintains a pressure differential between the downstream pressure and the pressure in the interior space at a value which effectively prevents the other gases from flowing into the interior space while minimizing power requirements of the seal gas fan.