The Reliability and Risk Department prepares reliability and risk analyses, which usually serve as input to more complex analyses and optimizations. In Česká rafinérská, a.s., FMEA/FMECA analyses were performed, which were further used in analyses of maintenance optimization using the RCM method. The technical reports evaluating the reliability level of the Dukovany and Temelín nuclear power plants systems include FTA fault tree analyses, which are used to quantify the non-availability values of important safety functions. The FTA analyses were also used to determine the criticality of Net4Gas, s.r.o.'s transit gas network equipment.