“The reactor prototype at Leshan is the first solid evidence that China is, in fact, developing a nuclear-powered aircraft carrier,” said Jeffrey Lewis, a professor at Middlebury and one of the researchers on the project. “Operating a nuclear-powered aircraft carrier is an exclusive club, one that China looks set to join.”

Drawing on satellite images and public documents including project tenders, personnel files, environmental impact studies - and even a citizen’s complaint about noisy construction and excessive dust — they concluded a prototype reactor for naval propulsion was being built in the mountains of Mucheng township, some 70 miles (112 kilometers) southwest of Sichuan’s provincial capital Chengdu.