Lev Feoktistov, 74; Soviet Nuclear Weapons Designer

Lev Feoktistov, a leading Soviet nuclear weapons designer who later joined a wave of scientists urging nuclear disarmament, died Thursday--his 74th birthday--in Moscow of an apparent heart attack, Russian news agencies reported.

He was a member of the Russian Academy of Sciences and a department chairman at the academy’s Lebedev Physics Institute.

Feoktistov worked from 1951 until the late 1970s designing nuclear warheads in the Soviet Union’s Arzamas-16 and Chelyabinsk-70 facilities, according to “Nukes Are Not Forever,” a book he published in English in 1999.

He later moved to Moscow to work on civilian research. He became an active participant in the international Pugwash movement of scientists campaigning to eliminate nuclear weapons.