In the lush, misty valleys of southwest China, satellite images show the country’s increasing nuclear arms buildup, a force poised for a new age of superpower rivalry.
One such valley is called Zitong in Sichuan Province, where engineers have built new bunkers and ramparts. A new complex full of pipes suggests that the facility is processing highly dangerous materials.
In another valley is a double-fenced facility called Pingtong, where experts believe China produces plutonium-filled cores for nuclear warheads. The main structure, dominated by a 360-foot-tall ventilation chimney, has been renovated in recent years with new vents and heat diffusers. Additionally, further construction work is underway.
Above the entrance to the Pingtong facility appears a signature exhortation from Chinese leader Xi Jinping in characters so large they are visible from space: “Stay true to the founding mission and always remember our mission.”
These are several secret nuclear sites in Sichuan Province that have been expanded and modernized in recent years.
China’s construction is complicating efforts at revival Global arms controls after the expiry of the last remaining nuclear weapons treaty between the United States and Russia. Washington argues that any successor agreements would also have to bind China, but Beijing has shown no interest.
“The changes we are seeing on the ground at these sites are consistent with China’s broader goals of becoming a global superpower. Nuclear weapons are an essential part of this,” he said Renny Babiarza geointelligence expert who analyzed satellite images and other visual evidence of the sites and shared his findings with The New York Times.
He likened each nuclear site across China to a piece of a mosaic that, taken as a whole, shows a pattern of rapid growth. “There has been development in all of these locations, but broadly speaking that change has accelerated from 2019 onwards,” he said.
China’s nuclear expansion is causing increasing tensions with the USA. Thomas G. DiNanno, Under Secretary of State for Arms Control and International Security at the State Department, publicly this month accused China of carrying it out secretly “Nuclear explosive testing” in violation of a global moratorium. Beijing has rejected the lawsuit as untrue, and Experts have debated this how strong the evidence is for Mr. DiNanno’s claims.
China had more than 600 nuclear warheads by the end of 2024 That number is expected to reach 1,000 by 2030, according to the Pentagon’s latest annual estimate. China’s stockpiles are much smaller than the many thousands of stocks held by the United States and Russia, but their growth is still problematic, he said Matthew Sharpa former State Department official who is now a senior fellow at the Center for Nuclear Security Policy at the Massachusetts Institute of Technology.
“I think without real dialogue on these issues, which we lack, it’s really hard to say where we’re going, and that to me is dangerous,” he said, “because now we’re forced to react and plan based on the worst-case interpretation of a worrying trend line.”
The locations in Sichuan were built six decades ago as part of Mao Zedong’s “Third Front,” a project to protect China’s nuclear weapons laboratories and facilities from attack by the United States or the Soviet Union.
Tens of thousands of scientists, engineers and workers worked in secret to carve into the mountainous interior what Danny B. Stillman, an American nuclear scientist who visited the area, later called “an inland nuclear empire” in a book he co-authored.
As China’s tensions with Washington and Moscow eased in the 1980s, many of the Third Front’s nuclear facilities were closed or downsized, often moving their scientists to a new weapons laboratory in the nearby city of Mianyang. Sites such as Pingtong and Zitong remained operational, but changes in subsequent years were piecemeal, reflecting China’s policy at the time of maintaining a relatively small nuclear arsenal, Dr. Babiarz.
This era of restraint has been over for about seven years. China quickly began building or modernizing many nuclear weapons facilities, and construction at the Sichuan sites also accelerated, Dr. Babiarz. The structure includes a huge laboratory for laser ignition in Mianyang, which could be used to study nuclear warheads without having to detonate real weapons.
The design of the Pingtong complex suggests that, according to Dr. Babiarz is used to make the pits of nuclear warheads – the metal core that usually contains plutonium. He noted that its architecture was similar to that of mining facilities in other countries, including the Los Alamos National Laboratory in the United States.
At Zitong, the new bunkers and ramparts will likely be used to test “high explosives,” experts say, referring to the chemical compounds that explode and create the conditions for a chain reaction in nuclear material.
“You have a layer of high explosive and the shock wave simultaneously implodes into the middle. Explosive testing is required to perfect it,” he said Hui Zhanga physicist who researches China’s nuclear programs at Harvard University’s Kennedy School of Government and the results of Dr. Babiarz examined.
The complex covers an oval area about the size of 10 basketball courts.
The exact goal of these upgrades remains controversial. Dr. Zhang said satellite images alone provide limited information. “We don’t know how many warheads have been produced, but all we see is the expansion of the plant,” he said.
Some of the recent changes may simply reflect safety improvements, Dr. said. Zhang, the Author of a new book“The Untold Story of China’s Nuclear Weapons Development and Testing.” Chinese nuclear engineers may also need more facilities and testing areas in Zitong to modify warhead designs for new weapons such as submarine missiles, he said.
A major concern for Washington is how this larger, more modern arsenal could change China’s behavior in a crisis, particularly with regard to Taiwan.
China wants to be “in a position where it believes it is largely immune to nuclear coercion by the United States,” he said Michael S Chasea former U.S. assistant secretary of defense for China who is now a senior political scientist at RAND. “I think they probably assume that this could play a role in a conventional conflict over Taiwan.”
Note: Research into the sites by Renny Babiarz’s company AllSource Analysis was funded by two organizations – the Open Nuclear Network and the Verification Research, Training and Information Center – which received support for the work from the Government of Canada. The New York Times acquired its own additional satellite images of the sites and shared those images and Dr. Babiarz with other nuclear weapons experts for assessment.
Top image sources: Airbus satellite images, September 9, 2022 and February 5, 2026
