China’s Historical Plutonium Production
Authors | Editors: Swegle, J. (National Strategic Research Institute); Yeaw, C. (National Strategic Research Institute)
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In this paper, we reevaluate China’s production of weapons-grade plutonium (WGPu) in order to estimate the maximum number of nuclear weapons using WGPu that China could build.† This WGPu was produced in the 801 Reactor at the 404 Plant in Gansu Province (or the 404 Plant reactor) and the 821 Plant reactor in Sichuan Province. Both are graphite-moderated, light-water-cooled production reactors that began operation in late 1966 and late 1973, respectively, and both have been shut down for decades (with the date of termination at issue between different authors). We know of no openly available information indicating that China has resumed WGPu production elsewhere.
We review two existing estimates of WGPu production with widely varying methodologies and results: Zhang’s 2017 estimate and Esin and Anichkina’s 2013 estimate. In addition, we provide our own estimate based largely on the information in Zhang’s paper, but with a reconsideration of Zhang’s assumptions about the pace of production for 1980 and beyond and on his assumption about the closure date of the 821 Plant reactor.
Our primary findings are the following:
- Zhang and Esin and Anichkina essentially agree on the WGPu production in the 404 Plant reactor, with a small difference largely due to Zhang’s 600 MWt reactor power, based on a 1990 Chinese-language publication, and Esin and Anichkina’s 500 MWt reactor power, based on proprietary conversations with Russian scientists who claim to have worked with the Chinese prior to a break between the Soviet Union and China.
- Zhang and Esin and Anichkina differ dramatically on WGPu production in the 821 Plant reactor. Zhang relied on information from former plant workers and assumptions based on the political context with regard to nuclear power at the time in China. Esin and Anichkina relied heavily on proprietary discussions with Russian scientists who claimed to have personally participated with the Chinese in developing their nuclear complex. Esin and Anichkina’s estimates were more conditional, and they employed a much higher reactor power and the assumption that the reactor continued to produce WGPu well after former Chinese workers claimed production had ended. Ultimately, we found quantitative elements of the Russian estimate, which was much larger than Zhang’s, to be problematic.
- We reevaluated Zhang’s estimate, focusing on his assumptions about production reductions after 1979 and the termination date for military production at the 821 Plant. This reevaluation resulted in a 50 percent increase over Zhang’s estimate, from 3,450 kilograms to 5,200 kilograms. This increase could permit China to build, or have built, over 1,000 plutonium-based nuclear devices.
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