TECHNOLOGY R&D FOR HCD POWER SUPPLIES FOR DEMO

My thesis regards the technology R&D and integration studies for the power supplies of the Electro Cyclotron Resonant Heating (ECRH) and Neutral Beam Injector (NBI) systems of DEMO power plant, the last stand in fusion research towards an industry and technology driven fusion reactor. Despite the actual HCD for DEMO is ECRH-focused, the NBI is still in the framework of the “Perspective R&D task” of Eurofusion, as a good candidate to be included in the HCD final mix, relying in particular on the achieved performance of the ITER HNBI. The performances required to the ITER HNBI have never been achieved so far and they are so demanding that it was deemed necessary to realize a test facility (NBTF) with prototypes in scale 1:1 of the negative ion source and the accelerator, namely SPIDER and MITICA. In this respect, I contributed to the development and integration studies for the substitution of the RF oscillator supplying the negative ion sources of SPIDER and MITICA experiments with RF solid-state amplifiers. These studies aim to develop the conceptual design of the overall RF circuit, to define a special load mimicking the real load of the ion source of SPIDER and MITICA and a set of special tests under conditions similar to the ones experience during SPIDER experimental campaigns to verify at best its reliability and strength prior the installation on site, to follow-up the Supplier’s activities for the system detailed design, manufacturing and test. Regarding the ECRH system of DEMO, the aim of my thesis was to investigate the suitability of the actual technology foreseen for the high voltage power supplies of the gyrotrons and on the possible optimization that could be provided to the system. During the review of DEMO ECRH system the proposal for a new, simpler and cost-saving solution able to meet the desired system operating requirements has been advanced. The conceptual design of this power supply and the integration within the DEMO ECRH system is analyzed and discussed with respect to the current technology.