A hydraulic system designed to provide power to all closure elements of the rig's blowout preventer stack. Hydraulic oil is forced into one or more vessels by a high-pressure, small-volume pump and Its charge of Inert gas, usually nitrogen. The gas is compressed and stores potential energy. When the system is actuated, the oil under high pressure is released and opens or closes the valves on the BOP stack.

The following video provides you with the correct English pronunciation of the word "ACCUMULATOR SYSTEM", to help you become a better English speaker.