By William J. Broad, Chris Buckley and Jonathan Corum
In the remote desert where China detonated its first atomic bomb nearly 60 years ago, a drilling rig recently bored a deep vertical shaft that is estimated to plunge down at least a third of a mile. It is the strongest evidence yet that Beijing is weighing whether to test a new generation of nuclear arms that could increase the lethality of its rapidly expanding missile force.
For years, U.S. government reports and independent experts have expressed vague concerns about the old base, Lop Nur. The reports point to possible preparations for year-round operations and a “lack of transparency.”
Now, however, waves of satellite images reveal that the military base has newly drilled boreholes — ideal for bottling up firestorms of deadly radiation from large nuclear blasts — as well as hundreds of other upgrades and expansions.
“All the evidence points to China making preparations that would let it resume nuclear tests,” said Tong Zhao, a nuclear expert at the Carnegie Endowment for International Peace.
Siegfried S. Hecker, a former director of the Los Alamos weapons laboratory in New Mexico, described Lop Nur’s rebuilding as unusual. “The Russians and Americans have continued activity at their test sites,” he said, “but nothing like this.”
Analysts say the activity at Lop Nur signals a wide modernization of China’s nuclear establishment, warning that it could spark a new age of atomic rivalry.
They add that China’s moves, along with those of other nuclear powers, could undermine the global test ban that began in 1996. The world’s atomic powers signed it after the Cold War as a way to curb a costly nuclear arms race.
The new evidence at Lop Nur was uncovered by Renny Babiarz, a former analyst at the National Geospatial-Intelligence Agency, an arm of the Pentagon. An expert on satellite reconnaissance as well as Beijing’s nuclear program, Babiarz says that detonations in the deep shafts could accelerate an effort to perfect new types of nuclear arms for the country’s fast-growing arsenal. Independent experts who have examined the satellite imagery and Babiarz’s analyses share his concerns.
The activity at Lop Nor comes at one of the most sensitive moments in U.S.-China relations. President Joe Biden has said he’s trying to “stabilize” an increasingly contentious relationship and, at a summit meeting last month with Xi Jinping, China’s leader, sought a measure of accord.
U.S. intelligence officials say they’ve followed Lop Nur’s revival for years. While the construction is obvious, they say, its purpose is not. China could be preparing for a nuclear test, they concede. But they add that Xi may not intend to move ahead unless the United States or Russia go first. The officials say Xi could be hedging his bets, drilling the deep vertical shafts so that, if necessary, China can act quickly.
Last week, the Foreign Ministry in Beijing responded to questions about upgrades at Lop Nur, dismissing them in a statement as “clutching at shadows, groundlessly whipping up a ‘China nuclear threat.’” It called such claims “utterly irresponsible.”
The ministry also emphasized Beijing’s commitment to observing the nuclear test ban. China, it said, will spare “no effort to realize the noble aspiration of comprehensively banning and totally eradicating nuclear weapons.”
Lop Nur is a sprawling military base, roughly the land area of Virginia, in the arid Xinjiang region of China’s far west. Chinese accounts say the area was chosen for nuclear tests because it was so barren and isolated, without any permanent residents. But the broader Xinjiang region is home to the Uyghurs, a largely Muslim ethnic group that has recently endured mass detentions and pervasive security controls.
The Uyghurs have long protested health threats from nuclear tests at the site, which began in 1964 after Mao Zedong decided to build the bomb. The early tests were capped by mushroom clouds and radioactive fallout. China conducted its first underground nuclear test in 1969.
At first, China used shallow horizontal tunnels. It was a relative latecomer to drilling vertical shafts that were deep enough to reliably contain the deadly radiation, especially for large blasts. Its first such shaft test occurred in 1978.
After the Cold War, the Lop Nur test site ended its large blasts and became a relative backwater.
That began to change after 2012, when Xi came to power. The Chinese leader saw the Rocket Force, which he created in late 2015, as one of his glories. The elite organization, the custodian of China’s nuclear weapons, embodied Xi’s ambitions to elevate his country as a great power ready to stand up to the United States.
Xi’s political rise, it turns out, coincided with Lop Nur’s rebirth.
Nuclear experts say they see no signs of an imminent Chinese test and argue that Beijing may do nothing. The rebuilding of the military base could simply be a warning to the West, they say. Chinese experts have suggested as much.
Other analysts disagree, arguing that China’s fleets of new bombers, submarines and missile silos herald a push for new armaments.
China could field 1,500 nuclear warheads by 2035 at its current pace of force expansion, the Pentagon has projected. That figure would be a fivefold increase from the “minimum deterrent” that China possessed for more than half a century.
American experts say Chinese scientists are now planning the particular arms they see as best suited for that buildup and may learn much from test explosions.
What China wants most, experts say, is miniaturization. With new, more accurate missiles that pinpoint targets, its scientists can reduce the power, size and cost of warheads.
Experts say miniaturization could make China’s submarine missiles more deadly. Miniaturization could also aid China’s development of hypersonic warheads that would zig and zag to evade U.S. defenses.
American experts cast Lop Nur’s modernization as a sign of just how far the Chinese may be willing to go.
“We have to realize that they had a conservative posture,” said Terry C. Wallace, a former Los Alamos director who has long studied China’s program of nuclear experimentation. “That’s changing.”