When Norsk Hydro began producing deuterium oxide (heavy water) in 1934, Norway became the first country with a commercial heavy water plant. The Nazi invasion of Norway in 1940 transferred control of the plant—and most of the world's deuterium oxide—to Germany. In the early 1940s, Allied countries joined the race for heavy water, and by 1944, the Manhattan Project had made 20 tons of the precious liquid, more than enough to fill the first heavy water nuclear reactor.
America's atomic weapons program ultimately relied more on graphite than on heavy water in nuclear reactors, but the United States has continued to produce deuterium oxide for military use ever since the '40s. Today, Canada and India, which both rely on heavy water nuclear power plants for electricity, make the most heavy water. Other countries with heavy water production facilities include Argentina, Iran, Romania, and Russia.
Fig 1. Norsk Hydro – Norwegian heavy water facility
Fig 2. Iran heavy water production plant
Source:
http://www.pbs.org/wgbh/nova/hydro/water.html
