Question: What project was a scientific effort led by Germany to develop and produce nuclear weapons during World War II, and was subject to the Norweigian heavy water sabotage to prevent it?
Sentence (from "Operation Freshman"): The source of the heavy water was the Norsk Hydro plant, which had been occupied in 1940; when the British government learned of the German nuclear developments, it was decided that a raid would be launched to destroy the plant and deny the Germans the heavy water required to develop a nuclear weapon.
Relevant evidence: No