Simulation and Simulators for Nuclear Power Generation

TLDR: This chapter deals with simulation, a very powerful tool in designing, constructing and operating nuclear power generating facilities and the examples mentioned in this chapter originate from experience with water cooled and water moderated thermal reactors, based on fission of uranium-235.

Abstract: This chapter deals with simulation, a very powerful tool in designing, constructing and operating nuclear power generating facilities. There are very different types of power plants, and the examples mentioned in this chapter originate from experience with water cooled and water moderated thermal reactors, based on fission of uranium-235. Nevertheless, the methodological achievements in simulation mentioned below can definitely be used not only for this particular type of nuclear power generating reactor. Simulation means: investigation of processes in the time domain. We can calculate the characteristics and properties of different systems, e.g. we can design a bridge over a river, but if we calculate how it would respond to a thunderstorm with high winds, its movement can or can not evolve after a certain time into destructive oscillation – this type of calculations are called simulation. For simple systems we probably can reach an analytical solution to show that a given system is damped enough to stay stable without oscillation even in very different circumstances. Simulation steps in when the systems are too sophisticated to reach any analytical solution. Unfortunately, if we want to reach correct and accurate results we usually end up with very sophisticated and non-linear system description. This unavoidable leads us to simulation. According to some authors, probably the last engineering achievement made completely without simulation was the Empire State Building. The Boeing 777 was mentioned as the first construction the design of which was completely unthinkable without simulation. (Janosy, 2003) We need simulation if: • The processes are too sophisticated and they have too many physical states just to think about everything • It is too expensive and/or dangerous to build a prototype just for testing – or even if we have a prototype, we are very limited in testing and checking it under very different circumstances due to the costs and unavoidable dangers • We want to check properties and compare different solutions under extreme conditions. All these conditions are present in designing, constructing or operating a nuclear power generating system (Janosy, 2007 November).