Guys everything is based on estimate nobody know for sure how many nuke China has since they didn't disclose it. Here it is how they estimate the Pu production interesting article
ESTIMATING CHINA’S MILITARY PLUTONIUM PRODUCTION The range of published estimates of China’s military plutonium production is very broad. In their first book estimating fissile material stockpiles, Albright, Berkhout, and Walker32 estimated that China had produced from 1 to 4 tonnes of plutonium. On the other hand, Norris, Burrows, and Fieldhouse33 give an estimate of roughly 4 to 7 tonnes with an upper bound of 15 tonnes. The difference in these estimates appears to result primarily from estimates of the power of the production reactors, as we discuss below. We attempt in this section to develop an independent estimate.
(1) where XPu is the amount of plutonium produced annually (in kilograms per year); C is the capacity factor, which is typically between 0.5 and 1; Pth is the thermal power of the reactor (in megawatts); and β is the amount of plutonium produced per megawatt-day of operation, which depends on the specific burnup of the fuel and thus on the fraction of Pu-240 in the extracted plutonium. For burnups that give a Pu-240 content in the range of 3–6%, the value of β is in the range 9.0–8.5 × 10−4 kg/MWd, or just under 1 gram per megawatt-day (see Appendix A; the value of β for U.S. plutonium production at Hanford was34 8.2 × 10−4 kg/MWd). TJ715-04 SGS.cls April 15, 2003 21:50
Estimating China’s Weapons Plutonium Production 67 The reactor power, the capacity factor, and the specific burnup of the fuel will, in general, change over the lifetime of the reactor. We estimate these quantities based in part on the history of the Jiuquan reactor sketched above, as well as on knowledge of the U.S. and Soviet production programs. Estimating the Reactor Power at Jiuquan There is little reliable information about the power of either of China’s production reactors. For the Jiuquan reactor, Albright et al.,35 assume a reactor in the range of 400–600 MWth. Norris et al.,36 on the other hand, state that the reactor may have been able to produce 300–400 kg of plutonium annually, which would require a maximum power of 1400–1900 MWth, assuming a capacity factor of 70% and 6% Pu-240 content.
This figure appears to be based on a U.S. Defense Intelligence Agency (DIA) estimate from 1972, which likely came from satellite photos of the facility. Several other references also give estimates of reactor size or annual plutonium production, but the reliability of these figures is uncertain. A 1969 Sunday Times of London article, written by a journalist who visited China, states that a Chinese source told him that the Jiuquan facility could produce more than 300 kg of plutonium annually.37 A 1985 article in The China Business Review states without giving a source that this plant could produce about 400 kg annually.38 On the other hand, a German study gives a lower figure, stating that the Jiuquan reactor power is 600 MWth and produces 200 kg weapon-grade plutonium per year.39 We note that a 600 MWth reactor could only produce 200 kg of plutonium annually if it operated with a capacity factor of 100%. Assuming a capacity factor of 70% and 6% Pu-240, a 600 MWth reactor could produce only 130 kg of plutonium annually; alternately, producing 200 kg annually would require a 900 MWth reactor.
Jeffrey Lewis is the one who proposed 300 nuclear warhead count
Based on this Now this guy Xue Litai, China Builds the Bomb (Stanford, CA: Stanford University Press, 1988) and John Lewis Actually work in Chinese nuclear facility in 80 's and he went to MIT for further study and coauthor with Jeffrey lewis the estimate.
Estimating China’s Production of Plutonium for Weapons David Wright and Lisbeth Gronlund1 January 16, 2003 This paper discusses the history of China’s production of plutonium for nuclear weapons, and uses that history and analogies to the production process in the United States and Russia to estimate the amount of plutonium China produced at its two known facilities. That analysis leads to an estimate that China produced 2 to 5 tonnes of plutonium at these facilities before it ceased production around 1990. The paper describes how the analysis was done and what assumptions were used so that a reader can understand how the results are affected by different assumptions or by new information that might become available.
Given the lack of information available about most aspects of China's nuclear-weapon program, the estimate of plutonium production developed in this paper is necessarily rough. However, even a rough estimate is interesting since the size of China’s fissile material stockpiles will influence China's willingness to join a multilateral “cut-off” convention to ban future production of fissile material for weapons or outside of safeguards. History of Chinese Plutonium Production Plutonium is produced by irradiating uranium-238 with neutrons in a nuclear reactor and then extracting the plutonium from the mixture of plutonium, uranium, and fission products that result from the fission of the uranium and plutonium. Thus a production complex must contain a production reactor and a reprocessing facility to separate the plutonium.
China is believed to have produced plutonium for weapons at two facilities: (1) the Jiuquan Atomic Energy Complex (also referred as Plant 404 or the Yumen or Subei facility, after a nearby cityand county), where the first production reactor began operating in late 1966, and (2) the Guangyuan facility (or Plant 821), one of the so-called "Third Line" facilities, which probably began operating in the mid-1970s. Below we first describe the history of the facilities and then estimate their output.
Our discussion of the Chinese production complex draws heavily on information available in the official Chinese history of its nuclear industry,2 and on the work of Lewis and Xue.3 1 David Wright and Lisbeth Gronlund are Co-Directors and Senior Scientists in the Global Security Program at the Union of Concerned Scientists, and Research Scientists in the Security Studies Program at MIT. 2 Li Jue, et al., eds., Tang Tai Chung-kuo Ti Ho Kung Yeh [China Today: Nuclear Industry] (First Edition) (Beijing, 1987). Selections are translated in Foreign Broadcast Information Service, US Department of Commerce Joint Publications Research Service, JPRS Report—Science and Technology: China, JPRS-CST-88-002, 15 January 1988 and JPRS-CST-88-008, 26 April 1988. 3 John Lewis and Xue Litai, China Builds the Bomb (Stanford, CA: Stanford University Press, 1988) and John Lewis
