Diagnostic neutral beam for ITER - Concept to engineering

Following the allocation of procurement of the DNB to the Indian DA, a series of tasks have been undertaken to first assess the DNB configuration and arrive at an optimal beam line configuration folding in the requirements of gas feed and vacuum pumping requirements. Specific emphasis is placed on the thermal, structural and electrical design of beam line components, in order to ensure their compatibility with the criteria specified for ITER in vessel components (Structural Design Criteria for In-vessel Components-SDCIC). Detailed assessment of manufacturing technologies and their compatibility with the ITER standards forms an integral part of the design. A common approach to manufacturing for DNB and H&CD NB components shall be undertaken through a comprehensive prototyping phase which shall lead to Built to Print (BTP) specifications. In addition to safety and remote handling issues, the design also addresses the requirements of interfaces related to other systems such as cryo, hydraulic, pneumatic, vacuum pumping, gas feed, civil, power supplies and transmission, CODAC etc. Successful delivery of DNB is dependent on two critical R&D aspects - (1) production of a uniform, low divergence beam from the beam source and (2) a well controlled transmission through lengths of ~ 22 m. The first shall primarily be a subject of the Ion Source Test Facility - ISTF (part of Neutral Beam Test Facility - NBTF in Padova), where India is involved as a collaborator and the Indian test bed, where issues for DNB Beam Source which were not resolved in the ISTF would be taken up. The second shall form one of the primary objectives of the Indian Test Bed to characterize the DNB. The paper presents the progress in DNB from the concept level to an engineered system along with the plans for system integration and an R&D intensive implementation.