The Norwegian heavy water sabotage (Bokmål: Tungtvannsaksjonen; Nynorsk: Tungtvassaksjonen) was a series of Allied-led efforts to halt German heavy water production via hydroelectric plants in Nazi Germany-occupied Norway during World War II, involving both Norwegian commandos and Allied bombing raids. During the war, the Allies sought to inhibit the German development of nuclear weapons with the removal of heavy water and the destruction of heavy-water production plants. The Norwegian heavy water sabotage was aimed at the 60 MW Vemork power station at the Rjukan waterfall in Telemark.