I always thought it weird China had the smallest arsenal of the world’s five NPT nuclear-weapons states. In broad strategic terms, this would make it very vulnerable to the US, especially given the latter’s development of ABM technologies, which would potentially give it the choice of an annihilating first strike.
In late 2009, China went public with the news that it has a 5,000km system of tunnels, known as the Underground Great Wall (地下长城). This did not get much attention in the West apart from a small article at Jamestown, until a student group at Georgetown University compiled a long report on the 2nd Artillery Division’s tunnels which got wide coverage in the MSM. One of the most critical implications is that the PLA’s nuclear arsenal may well be underestimated by an order of magnitude, numbering about 3,500, with profound consequences for US – Russia disarmament talks. You can read about it, look at photos, or you can watch the video below which has the added bonus of featuring inspiring Chinese patriotic music.
The skeptics such as the Bulletin of Atomic Scientists and FAS* argue that such estimates are alarmist, hurt the case of disarmament, and implausible. China doesn’t have enough highly enriched uranium, and indeed, China’s tunnel system reflects its strategic weakness i.e. the lack of a proper nuclear triad and vulnerability of its land-based forces to an American first strike, hence the need to dig in deep. Project head Karber addresses most of these criticisms, noting that plutonium from civilian reactors hasn’t been converted and remains unaccounted for, and that in any case the Chinese constructed an underground reactor during the Third Front period. As for delivery, missile production isn’t all that technically complex and it is certainly feasible to build them underground far away from prying satellite cameras.