WHY WERE THE GERMANS INTERESTED IN HEAVY WATER?
" A few weeks before the war broke out in 1939, Professor Otto Hahn discovered the fission of Uranium at Kaiser Wilhelm Institute in Berlin. The combination of Uranium and D20 could make an atomic pile possible and produce plutonium. Plutonium is an artificial element. Before the war, heavy water was produced only in one place in large quantities, and that was at Vemork, in the Rjukan valley in Norway."
(Haukelid, Skis Against the Atom p. 70.)
(Haukelid, Skis Against the Atom p. 70.)
What is Heavy Water?
Picture Courtesy
Journal of Chemical Education,
"Heavy water is a form of water with a unique atomic structure and properties coveted for the production of nuclear power and weapons. Like ordinary water—H20—each molecule of heavy water contains two hydrogen atoms and one oxygen atom. The difference, though, lies in the hydrogen atoms. In ordinary water, each hydrogen atom has just a single proton in its nucleus. In heavy water, each hydrogen atom is indeed heavier, with a neutron as well as a proton in its nucleus. This isotope of hydrogen is called deuterium, and heavy water's more scientific name is deuterium oxide, abbreviated as D20."
(Hitler's Sunken Secret, PBS Nova)
(Hitler's Sunken Secret, PBS Nova)
Why is it dangerous?
Picture Courtesy U.S. Department of Energy;
"In its natural state, common uranium (U-238) can't generate destructive nuclear explosions. It either must be enriched—made more concentrated in a rare form of uranium (U-235)—or converted into plutonium (Pu-239). Heavy water can play a role in breeding weapons-grade plutonium from common uranium. In a heavy-water nuclear reactor, when neutrons bombard U-238, some uranium atoms absorb an additional neutron and are transformed into Pu-239.
On the eve of World War II, scientists both in Germany and Great Britain realized that heavy water could be used in this way to make nuclear weapons. And because this potential still exists today, the International Atomic Energy Agency and various national governments monitor the production and distribution of heavy water."
(Hitler's Sunken Secret, PBS Nova)
How was it Made?
Picture Courtesy of Norsk Industriarbeider Museum
"Heavy water is naturally present in ordinary water, so it's more accurate to speak of "isolating" rather than "making" it. Separating out significant quantities, though, is no easy trick because heavy water constitutes only one part in 4,500. Gilbert Lewis isolated the first samples in 1933 using electrolysis—sending an electric current through water to separate it into its elements. His technique relied on the fact that H20 breaks apart more readily than D20, and the residual water left after electrolysis is relatively rich in D20. By reprocessing the residual water over and over again, he could eventually purify heavy water. With his lab equipment, however, Lewis's process was time-consuming and expensive.
Norsk Hydro, which already used electrolytic cells in the early 1930s to make fertilizer, seized the chance to make heavy water on an industrial scale. By 1935, the Norwegian company was shipping heavy water to scientists throughout Europe who wanted it for physics, chemistry, and biomedical research."
(Hitler's Sunken Secret, PBS Nova)