Risk modelling of ageing nuclear reactor systems

A nuclear reactor is expected to function for extensive periods, during which, coolant circulation and core reactivity must always be maintained safely. Understanding the risks associated with operation of such systems requires proper consideration ageing components effects preventative maintenance. The traditional methodologies, as Fault Trees Event Trees, have limitations in their abilities model processes complex maintenance strategies. Petri Nets been used this research a more suitable alternative. case study presented demonstrate capability. were developed five key subsystems: primary circulation, shutdown condensation, emergency injection, shutdown, control monitoring, building representation which considers failure modes, reaction system faults, ongoing component actions. These models reveal statistics timing these subsystems relative frequencies outcome categories.