Simulators are the Key for Large-Scale Instrumentation and Control System Refurbishment Projects

With proper operation and waste management the nuclear fission power is one of the clearest and cheapest energy sources: no gases are emitted during the energy generation and other related preparatory etc. processes. The upcoming nuclear-fusion-based power plants are even more promising; all contamination in these plants will be decayed practically to nil in less than 100 years. Renewable energy sources can play an important, but only a supplementary role, at least for the foreseeable future. In the paper the author summarize the results and practice we used at Paks NPP in Hungary, first in the evaluation of safety studies, then in the working-out of new state-of-art operational procedures, and finally, during reconstruction of the reactor safety system and other I&C Systems, the replacement of which - thanks to the extensive testing and tuning performed using the full-scope replica simulator - was completed during the regular re-fuelling outage of the NPP units.