There is one center tank and a left and right main tank. All tanks are an integral part of the wing. Each main tank is vented to a vent box in he opposite wingtip.
Each fuel tank has two AC boost pumps installed. A DC powered start pump is installed in he right main tank to provide fuel pressure for start of the APU or an engine if AC power is not available. This switch is placed on Engine starter panel.
During normal operation, he left main tank supplies the left engine and the right main tank supplies the right engine. The center tank fuel is transferred into left and right main tanks.
Later aircraft are equipped with an alternate Fuel Burn system. In these aircraft the center tank pump switches have three positions. The system is designed to reduce the risk of cold fuel reaching the upper part of the wing after landing. Thus reducing the risk of clear ice forming on the upper surface of the wing.