Engineering and design aspects related to the development of the ITER divertor

The adaptation of the high-recycling divertor concept for ITER is not possible because, owing to the increase in fusion power to 1.5 GW, the resulting loads on the divertor target plates are in excess of 35 MW m−2. Therefore a novel concept is proposed, based on observations of power reduction by about one order of magnitude in existing tokamaks at high-density operation. It will allow for a viable approach to the problems of energy and particle exhaust, helium pumping and impurity control at an adequate lifetime of the divertor. ncept is based on radiation and momentum exhaust along the divertor channel, and relies on the fact that a substantial fraction of the incoming power can be radiated as long as the plasma pressure is balanced not only by plasma and neutral particles in front of the target plates but also dynamically by high fluxes of recycling particles. Therefore this operating regime is called the dynamic gas target divertor. aper describes the design and the development of the ITER divertor and shows how the physics requirements have been translated into engineering solutions, and how the additionally existing constraints (such as the space limitations, neutron effects, electromagnetic loads, compatibility with other components, easy maintainability, etc.) have been taken into account.