During the weeks to come we will examine various types of nuclear power plants and explain how the generation of electricity in those plants is possible.

kraftwerk gersteinwerk luftbild - rwe pressebilder
© rwe pressebilder

With the start of the civil use of nuclear power in the mid of the 20th century expectations were high. The electricity from nuclear plants was expected to be “too cheap to meter”. These hopes however could only be fulfilled partly.

Several devastating accidents around the world (Three Mile Island in the US, Chernobyl in the Ukraine, as well as Fukushima in Japan) did not only harm human lives and the environment, but also resulted in the development of ever more cost-intensive security systems for nuclear power plants. Thus, nuclear power today is not “too cheap to meter” after all – resistance in the population, as well as very long procedures for obtaining permits led to increasing costs.

Still, civil use of nuclear power shapes the energy sector until today; and will do so for the years to come. Different countries do however assess the future of nuclear power in diverging ways: While Germany phases out its nuclear power generation until 2022, several new nuclear reactors are being developed and constructed in Finland, France, UK and China.

Two different reactor designs of nuclear power plants exist in Germany:

  • Boiling water reactor (BWR)
  • Pressurized water reactor (PWR)

Both types belong to the group of light water reactors. They utilize light water (common H2O). Uranium is the fuel for both types. While natural uranium consists of 99.3% uranium-239 and only of 0.7% fissile uranium-235, the latter is required to operate nuclear power plants. Depending on the reactor design uranium-235 has to be enriched before being used as a fuel for generating electricity in nuclear power plants.

Nuclear power plants are characterized by high investment costs and low variable electricity generation costs. Due to low operating costs and sluggish start-up and stop behavior, such power plant types are typical base load power plants.

When a reactor is fully fitted with fuel elements, roughly one-third of the elements have to be replaced in intervals of one year. For that end, the power plant will be taken off the grid and a revision is carried through.