Status of PRIMA, the Test Facility for ITER Neutral Beam Injectors

To experimentally demonstrate the sustainability of the fusion reactions with a Q factor ranging from 5 to 10 in stationary conditions, the ITER project requires additional heating by two neutral beam injectors (HNB). Each HNB will accelerate to 1 MV a 40 A beam of negative deuterons delivering to the plasma a total power of 33 MW up to one hour. These requirements have never been experimentally met; hence a strong demonstration activity has been endorsed by ITER to optimise the crucial components and systems. A test facility, PRIMA (Padova Research on ITER Megavolt Accelerator), is presently in the starting phase of construction and procurement at Consorzio RFX (Padova, Italy) in the CNR research area. The facility requires the construction of new buildings (2 ha) and the adaptation of the existing 400 kV power substation. A full-size negative ion source, SPIDER (Source for the Production of Ions of Deuterium Extracted from Rf plasma), will be operated in the facility to demonstrate the creation and extraction of a D?/H? current up to 50/60 A on a wide surface (more than 1 m2) with uniformity within 10 %. The ITER diagnostic beam injector, to be built by the Indian Domestic Agency, shares some requirements and components with SPIDER and close collaboration exists. All SPIDER plant systems and components are ready for the procurement phase. The second experimental device is the prototype of the whole ITER injector, MITICA (Megavolt ITer Injector and Concept Advancement), aiming to develop the knowledge and the technologies to guarantee the successful operation of the two injectors to be installed in ITER, including the capability of 1 MV voltage holding at low pressure. The Japan Domestic Agency will contribute to the construction of MITICA. Many MITICA plant systems and components are well developed and close to be ready for procurement. The experimental effort is supplemented by numerical simulations devoted to the optimisation of the accelerator optics and to the estimation of heat loads and currents on the various surfaces. Laboratories, such as KIT-Karlsruhe, IPP-Garching, CCFE-Culham, CEACadarache and other European research institutions are also cooperating to the success of the PRIMA enterprise. In the paper the main requirements will be discussed and the design of the main components and systems will be described. Finally the status and planning of PRIMA will be presented. This work was set up in collaboration and financial support of F4E.