The ITER power and particle control system is designed to exhaust the 300 to 400 MW of alpha and auxiliary heating power and the 5 × 1020 He atoms per second created by the fusion reactions, to control the density and to fuel the plasma. The power and particle control system consists of a single null poloidal divertor, a set of active pumps with a total pumping speed of ~ 200 m3/s, and gas puffing and pellet fuelling systems. Atomic processes are used to spread out the heating power over the first wall and divertor walls, thereby reducing the peak heat loads on the divertor plates to acceptable levels. The divertor has a “vertical target” plate configuration and tight baffling to maximize the effectiveness of the atomic processes for energy losses in the divertor and to maximize the neutral pressure in the divertor and minimize the backflow of neutrals from the divertor to the main chamber.