This Standard establishes requirements for the supplementary control points provided to enable the operating staff of nuclear power plants to shut down the reactor and maintain the plant in a safe shut-down state in the event that control of the safety functions can no longer be exercised from the main control room, due to unavailability of the main control room or its facilities. It also establishes requirements for the selection of functions, the design and organisation of the human-machine interface, and the procedures which shall be used systematically to verify and validate the functional design of the supplementary control points.