Project Sapphire was a successful 1994 covert operation of the United States government in cooperation with the Kazakhstan government to reduce the threat of nuclear proliferation as part of the Cooperative Threat Reduction Program. A warehouse at the Ulba Metallurgical Plant outside Ust-Kamenogorsk housed 1,322 pounds (600 kg) of weapons grade enriched uranium to fuel Alfa class submarines (90% U-235).