It is well known that the electrical-power generation is the key factor for advances in industry, agriculture and level of living. In general, electrical energy can be generated by 1) non-renewable-energy sources such as coal, natural gas, oil, and nuclear; and 2) renewable-energy sources such as hydro, wind, solar, biomass, geothermal and marine. However, the main sources for electrical-energy generation are 1) thermal primary coal and secondary natural gas; 2) "large" hydro and 3) nuclear. The rest of the energy sources might have visible impact just in some countries. The presentation will be related to the current status of nuclear-power industry in the world and a comparison of nuclear-energy systems to other energy systems.