China is a nuclear weapon state member of the Non-Proliferation Treaty. Its nuclear arsenal is estimated to include 240 nuclear weapons, of which about 180 are believed to be operationally deployed. China's stockpile of fissile materials is estimated to include 16±4 tonnes of HEU and 1.8±0.5 tonnes of weapon-grade plutonium.
China has not declared officially that it has ended HEU and plutonium production for weapons, but it is believed to have done so. Production of HEU was stopped in 1987 and that of plutonium by about 1990.
China has produced highly enriched uranium (HEU) for weapons in two complexes: the Lanzhou gaseous diffusion plant (Plant 504) and the Heping gaseous diffusion plant (Plant 814). China used these enrichment plants also to produce HEU for its research reactors and LEU for naval reactors. The plant in Lanzhou began operations in 1964 and ended HEU production in 1979. The Heping plant produced HEU from 1975 to 1987. Both plants have been shut down.
Together, the Lanzhou and Heping gaseous diffusion plants therefore produced roughly 3.8 million SWU, enough to make abut 20 tons of weapon-grade HEU. Taking into account HEU and separative work consumed by research and naval reactors, tritium production reactors, used in nuclear tests, and lost in waste, the total amount of weapon-grade HEU in China's stockpile is estimated to be 16±4 tonnes.
China operates two centrifuge enrichment plants at Hanzhong (Shaanxi province), and at Lanzhou (Gansu province) to produce LEU for civilian purposes. There are also reports of a new plant using Chinese centrifuges near Lanzhou that began operating in 2010.
China has produced plutonium for weapons at two sites: the Jiuquan Atomic Energy Complex (also referred as Plant 404) near Yumen in Gansu province and the Guangyuan plutonium production complex (Plant 821), located at Guangyuan in
Sichuan province. The first plutonium production reactor at Jiuquan, which used graphite as moderator and water as the coolant, went critical in October 1966 and went into full operation in 1967. This reactor is believed to have been shut down in 1984. The reactor at Guangyuan, which appears to be similar in design and power to the one in Jiuquan, achieved criticality in December 1973 and design power by October 1974. It probably stopped plutonium production by 1989.
China’s two plutonium production reactors produced an estimated 2±0.5 tonnes of weapon-grade plutonium. Of this amount, about 200 kg of plutonium is estimated to have been consumed in China’s nuclear tests. The current inventory of weapon-grade plutonium is therefore estimated to be 1.8±0.5 tonnes.
China reports no inventory of separated civilian plutonium in its declaration to the IAEA, the most recent of which was for the end of 2007.