Control system design considerations for myrrha ADS

The accelerator is the first step of the accelerator driven system (ADS). A high power continuous wave accelerator is required for ADS applications. An essential aspect of accelerator for ADS is beam availability. It must be an order of magnitude better than current best systems. High availability may be achieved by fault tolerance and redundancy of the accelerator. Three factors play a key role here: use of components in a high MTBF regime, parallel and serial redundancy of components, ability to repair failing elements. In terms of accelerator controls system (CS) EPICS and Linux is chosen as proven technology. High availability will be achieved through making parts of the CS redundant. Subsystems shall be redundant by design. If failure of a subsystem is detected, pre-defined scenarios should kick-in. System model or "virtual accelerator" can be implemented to predict effects of parameter change, determine required configuration of set points for optimal performance or re-configuration in case of sub-system failure. Implementation of predictive diagnostics can harvest large amount of data created by archiving service. Prediction of failure allows for controlled shutdown as opposed to abrupt stop.