The History of Plutonium Production in China

China has kept information about its stocks of fissile materials and nuclear weapons secret. Based on new public information, it is believed China halted its plutonium production for weapons in 1987. This paper further reconstructs the history of China’s plutonium production at its two plutonium production complexes. Also the paper updates significantly estimates on China’s stockpile of plutonium for nuclear weapons. The new estimate is significant higher than other recent estimates.

China has produced plutonium for weapons at two sites: 1) Jiuquan Atomic Energy Complex (Plant 404) in Jiuquan, Gansu province. This site includes China’s first plutonium reactor (reactor 801) and associated reprocessing facilities. 2) Guangyuan plutonium production complex (Plant 821), located at Guangyuan in Sichuan province. This “third line” site also included a plutonium reactor (reactor 821) and reprocessing facility. While China has not declared officially that it has ended HEU and plutonium production for weapons, it appears that China halted its HEU and plutonium production for weapons in 1987.1

The Jiuquan plutonium production reactor reached criticality in October 1966, and reached its design power in the mid-1975.2 A great deal of effort went into increasing its plutonium production rate, which was increased by 20 percent by 1979. During the 1980s, after China pursued the “military to civilian conversion” policy, plutonium production decreased rapidly and the reactor was closed by November 1986. The Guangyuan reactor achieved criticality in December 1973 and its design power by October 1974. Subsequently, the plutonium production rate was increased 30 percent by 1978. However, under the “military to civilian conversion” policy, the reactor was shut down in 1984.

Based on then-available information, this author estimated in 2010 that China could have a stockpile of about 1.8±0.7 tons of plutonium for weapons.3 Based on newly available public information, this study estimates China’s current stockpile as about 2.9±0.6 tons of plutonium for weapons. The new estimate for plutonium stockpile is at the high end of a U.S. Department of Energy estimated range, reported in 1999, of 1.7–2.8 tons of weapon plutonium4 and significantly higher than other recent estimates.5