Porcelain based 100kV feedthrough for prototype ITER DNB at INTF

High Voltage Bushing (HVB) of the Indian Test Facility (INTF) of ITER Diagnostic Neutral Beam (DNB) is a porcelain-based 100 kV vacuum feedthrough. This will be used to feed the High Voltage (HV) supplies, coming from the HV deck to the Beam Source (BS) for the production of 100 kV H^- beam under high vacuum, therefore, it has two major functions: 1. Isolate 100 kV feedlines from grounded vessel and 2. Forms vacuum boundary with 25 feedline penetrations of different kinds. INTF HVB has been designed with rigorous iterations of design optimization for vacuum, mechanical, and electrical requirements. After design, the development of INTF HVB required several prototyping activities to address the challenges in establishing the appropriate bonding methodology with high vacuum compatibility, handling procedure of large size (∼800 mm diameter and 530 mm height) insulator, prior assessments of tolerances due to as-built ovality in insulator and testing & qualification at various steps, to establish the implementation plan for manufacturing and assembly. As a result, techniques, based on prototyping, manifest to solve the challenges were utilized in the manufacturing, leading to the successful development of the HVB.