Simulation Based Availability Optimization Of Dynamic Fault Compensation For Particle Accelerator RF Systems Applied To The MYRRHA Accelerator Driven System

The availability is a key performance indicator of modern accelerators. This is particularly the case for the MYRRHA linear accelerator, which needs to consistently deliver a particle beam to the MYRRHA reactor with minimal interruptions, each lasting no more than a few seconds, throughout a span of three months. This linear particle accelerator relies on a series of radiofrequency (RF) systems to accelerate the particle beam. These highly complex systems may prove to be a challenge for achieving high availability. A dynamic compensation scheme provides a remedy by allowing to continue beam operation despite the failure of individual RF systems, provided that they have sufficient power margin. The beam physics aspects of dynamic compensation have been studied in detail. However, its availability gains have only been quantified conceptually. An availability simulation model is introduced, which allows to quantify the availability gain of dynamic compensation whilst considering the findings of beam physics studies for optimizing power margins versus availability gain. For the MYRRHA linear accelerator, it is shown that a scheme of using four compensating per one faulty RF system provides a good balance between availability and power margin. Using more than four compensating RF systems would lead to a reduction in required power margins but also reduced fault-tolerance effectiveness and worse accelerator availability. Immediate repair of RF systems instead of repair during beam stops would only marginally improve availability under the foreseen operational scenarios of MYRRHA. These findings have been made possible due to improved and more detailed modelling. The study results highlight the importance of powerful availability simulation models and tools to maximize the effectiveness of advanced redundancy schemes. The developed model can be applied to optimize RF dynamic compensation schemes and helps advancing availability of particle accelerators.