The proton linac for the MYRRHA project

International audience; One mail goal of the European MYRRHA Project is the demonstration of the feasibility of thetransmutation of long-living radioactive nuclear waste. MYRRHA is designed as an acceleratordrivensystem (ADS) using a high-power cw proton accelerator coupled with a subcritical reactorwith a thermal power of up to 100 MW. The linac has to deliver 600 MeV protons with a nominalbeam current of 4 mA resulting in a beam power of 2.4 MW. The challenge of the linac developmentis the very-high reliability of the accelerator to limit the thermal stress inside the reactor. Whileparallel redundancy will be used in the injector, the required reliability in the main linac can beachieved by serial redundancy.The injector consists of an ECR source, a 1.5 MeV 4-Rod RFQ and a chain of CH drift tube structures.All injector structures are driven by 176 MHz solid state amplifiers. The medium energy sectionbetween 17 and 85 MeV consists of superconducting single spoke cavities operated at 352 MHz.The main acceleration is provided by 2 groups of superconducting elliptical 704 MHz 5-cell cavities.The MYRRHA linac layout has a very robust beam dynamics design with low emittance growth ratesto avoid excessive particle losses and machine activation.The project will be staged in three phases: The construction of the 100 MeV linac with firstexperimental stations, the energy upgrade to 600 MeV and the construction of the reactor. The RFQis presently under construction and will be tested with the already operational ECR source and LEBTsection. In a further step the construction of the whole injector and medium energy section isforeseen. This paper describes the linac design, prototype tests as well as the status of construction.