China enriched the uranium for its first atomic bomb in 1964 at the Lanzhou gaseous diffusion plant in Gansu province. In the 1970s, a second, much larger, plant was built in Sichuan province. According to conservative U.S. estimates, the two enrichment plants could have produced over 20,000 kilograms of weapon-grade uranium since 1964. This is enough fissile material to fuel more than 1,000 nuclear warheads.
China made its first plutonium for bombs in 1967 at the Jiuquan Atomic Energy Complex, the present-day hub of China’s nuclear weapon material production. The first Chinese bomb believed to incorporate plutonium was a thermonuclear warhead tested in late 1968. China built a second plutonium production reactor in Guangyuan in 1974. Analysts estimate that China’s inventory of weapon-grade plutonium from its two production reactors could be more than 3,500 kilograms, enough for roughly 700 nuclear warheads.