Acondicionamiento de acopladores y cavidades de radiofrecuencia para aceleradores de iones usados en instalaciones nucleares para el estudio de materiales para fusión

Abstract

Nuclear fusion is the energy source of the future and for its development, the International Fusion Materials Irradiation Facility (IFMIF)-DEMO Oriented Neutron Source (DONES) project aims to study the behavior of the first wall materials of future commercial reactors, under similar irradiation conditions. IFMIF-DONES is a neutron source based on the most powerful particle accelerator in the world, whose radiofrequency (RF) cavities and couplers will be state-of-the-art devices that will work in very demanding nominal conditions, so they must be previously prepared through a complex process called conditioning. This thesis adressess all the problems associated with conditioning and presents a proposal to implement the conditioning process affectively and safely. In order to validate the proposal experimentally, a high-power radiofrequency source to supply the RF, a conditioning test bench for the couplers of the Superconducting Radiofrequency (SRF) linear accelerator (Linac), and a clean room for assembly processes have been developed. The central topic of this thesis of the experimental validation of the proposal through the successful conditioning of the two prototype couplers of the SRF Linac of IFMIF, which allowed validating their design and launching the manufacturing of the eight-unit series for the Linear IFMIF Particle Accelerator (LIPAc). This coupler series was also successfully conditioned, improving the execution times of the original proposal by almost 30%. Additionally, also in LIPAc, an adaptation of the proposal likewise served to successfully condition the re-buncher cavities and to reach the nominal voltage in the Radiofrequency Quadrupole (RFQ) cavity. After the analysis of all the results and the presentation of the different possible improvements for the conditioning in the IFMIF-DONES project, a completely optimized process is proposed and an automation algorithm is designed, as well as all the necessary hardware. Finally, it will be essential to have an advanced conditioning laboratory at IFMIF-DONES facilities and for this, a first technical specificaction has been prepared, using the lessons learned during the thesis.