Sample of heavy water from Norsk Hydro

Heavy water contains the isotope deuterium instead of hydrogen and is used to control neutrons during a nuclear reactor's chain reaction. It is 11 percent heavier than ordinary water and has a relative molecular mass of 20, as compared to 18 for ordinary water.

This sample of heavy water is from Norsk Hydro, a Norwegian company, whose Vemork hydroelectric power plant, in Rjukan, Telemark, was famously attacked and sabotaged by Norwegian special forces during the Second World War in an attempt to destroy its stocks of heavy water, along with its heavy water production facilities. This was to deny Nazi Germany from using heavy water in its research and development of nuclear weapons - something which the Allies feared and tried consistently to prevent.

Heavy water contains the isotope deuterium instead of hydrogen and is used to control neutrons during a nuclear reactor's chain reaction. It is 11 percent heavier than ordinary water and has a relative molecular mass of 20, as compared to 18 for ordinary water.

This sample of heavy water is from Norsk Hydro, a Norwegian company, whose Vemork hydroelectric power plant, in Rjukan, Telemark, was famously attacked and sabotaged by Norwegian special forces during the Second World War in an attempt to destroy its stocks of heavy water, along with its heavy water production facilities. This was to deny Nazi Germany from using heavy water in its research and development of nuclear weapons - something which the Allies feared and tried consistently to prevent.