Most nuclear electricity is generated with two different types of nuclear reactors evolved from 1950 designs, namely the boiling water reactor (BWR) and the pressurized water reactor (PWR). The fuel for these types of reactors is similar, consisting of long bundles of 2 to 4 percent enriched uranium dioxide fuel pellets stacked in zirconium-alloy cladding tubes. In comparison, the electric power industry uses three different types of fossil fuel power plants, all generous producers of green house gases and other even more dangerous pollutants.
The BWR design consists of a single loop in which the entering water is turned directly to steam for the production of energy. The PWR design is a two-loop system that uses high pressure to maintain an all-liquid-water primary loop. Energy is transferred to the secondary steam loop through two to four steam generators. The PWR also uses a wet steam turbine.
Schematic representation of a pressurized water reactor (PWR)