Vemork
In 1911, the Vemork hydroelectric station in Rjukan started exploiting the tremendous power in the waters that flow from the mighty Hardangervidda down into the narrow Vestfjord valley. Norsk Hydro, Norway´s great industrial adventure, was born here, among the perilous cliffs and deep gorges.
Late in 1938, Lise Meitner, Otto Hahn and Fritz Strassman discovered the phenomenon of atomic fission. Physicists everywhere realized that if chain reactions could be tamed, fission could lead to a promising new source of power. What was needed was a substance that could "moderate" the energy of neutrons emitted in radioactive decay, so that they could be captured by other fissionable nuclei. Heavy water was a prime candidate for the job.
Allied forces were determined to stop Nazi Germany from developing the atomic bomb. Of two materials to control a nuclear reaction -— pure graphite and heavy water -- the Germans chose heavy water because of a mathematical error in calculating the use of graphite. The German nuclear research community relied on a supply of deuterium oxide [heavy water] from the Norwegian Norsk Hydro plant, the only commercial production facility. This plant in Vemork, Norway was the world's major source of heavy water in the early 1940s. In the United States, Heavy water was used as a coolant and moderator in nuclear materials production reactors at the Savannah River Site.
