Full nuclear weapons tests would backfire on US

Resuming full testing of nuclear weapons — as President Donald Trump called for last week — would be unnecessary, costly, undermine nonproliferation efforts, and empower the nation’s adversaries to use their own tests as intimidation, experts told Defense News.

Trump’s unexpected announcement, which came in the form of an Oct. 29 social media post, surprised many nuclear specialists — and sparked concerns that the United States may end its 33-year moratorium on nuclear weapons testing.

“Because of other countries testing programs, I have instructed the Department of War to start testing our Nuclear Weapons on an equal basis,” Trump posted on TruthSocial.

“That process will begin immediately,” he wrote.

When asked for comment about nuclear testing plans, the Pentagon’s public affairs office pointed to an Oct. 31 video of Defense Secretary Pete Hegseth in Malaysia, in which he said testing nuclear weapons is a responsible way to ensure the country has “the strongest, most capable nuclear arsenal so that we maintain peace through strength.”

“The president was clear: We need to have a credible nuclear deterrent,” Hegseth said, “That is the baseline of our deterrence.

“Having understanding and resuming testing is a pretty responsible — very responsible — way to do that. I think it makes nuclear conflict less likely, if you know what you have and make sure it operates properly,” he said.

Hegseth also said the military would work with the Energy Department on this testing.

Energy Secretary Chris Wright said on Fox News Nov. 2 that tests focusing on the subsystems of new nuclear weapons are already in the works, but he said the tests would not result in a full nuclear detonation.

“The tests we’re talking about right now are system tests,” Wright said. “These are not nuclear explosions. These are what we call non-critical explosions. So you’re testing all the other parts of a nuclear weapon to make sure they deliver the appropriate geometry and they set up the nuclear explosion.”

Fox News host Peter Doocy said it sounded like “this is not something where people who live in the Nevada desert should expect to see a mushroom cloud at some point.”

“No, no worries about that,” Wright said.

From ‘Trinity’ to ‘Divider’

The United States carried out 1,054 nuclear tests over nearly half a century. The first such explosion took place at the Trinity site in New Mexico in 1945 and is widely viewed as one of the pivotal moments of the 20th century. The final U.S. test — an underground detonation dubbed Divider — took place in September 1992 at the Nevada Test Site west of Las Vegas.

Then-President George H.W. Bush issued a temporary moratorium on nuclear testing following that detonation, which his successor, President Bill Clinton, extended indefinitely.

At the time, said John Erath, the senior policy director for the Washington-based Center for Arms Control and Non-Proliferation, a global movement against nuclear testing was on the rise. The United States joined that effort in part because it did not want other nations causing that kind of ecological damage, he said, but also because the U.S. was far ahead of the rest of the world.

“The U.S. had conducted over 1,000 nuclear tests,” Erath said Monday in an interview with Defense News. “We had all the data necessary to know how nuclear weapons work, to verify that U.S. nuclear weapons would work, and other people didn’t. So by stopping testing when we did, we sort of locked in an advantage in knowledge that persists to this day.”

Since then, U.S. nuclear testing has relied on computer simulations designed to predict how a weapon would respond if triggered.

Wright said on Fox News that the United States’ advanced laboratories and computing power devoted to nuclear weapons provide a major advantage over other nations.

“We can simulate incredibly accurately exactly what will happen in a nuclear explosion,” Wright said. “And we can do that because in the ’60s, ‘70s and ‘80s, we did nuclear test explosions. We had them detailedly instrumented, and we measured exactly what happened. Now we simulate what were the conditions that delivered that, and as we change bomb designs, what will they deliver?”

Hans Kristensen, director of the nuclear information project at the Federation of American Scientists, speaking Monday to Defense News, pointed to the Lawrence Livermore National Laboratory’s National Ignition Facility in California as an example of the kind of state-of-the-art facilities that the U.S. developed for safe nuclear testing purposes.

According to its website, the National Ignition Facility uses the largest and highest-energy laser system in the world to create controlled thermonuclear reactions and study them to ensure the U.S. nuclear stockpile will function as intended.

Its laser focuses more than 2 million joules of ultraviolet energy and up to 500 trillion watts of power onto a target the size of a pencil eraser, creating temperatures multiple times hotter than the sun, and massive pressures.

“These extreme conditions cause hydrogen atoms in the target to fuse and release energy in a controlled thermonuclear reaction,” the website reads.

As the government modernizes and extends the life of aging weapons in its nuclear stockpile, through efforts such as the W80-4 life extension program, it uses experiments at places such as the NIF to determine whether the weapons will still react properly if used.

Those simulation capabilities obviate the need for any testing of existing, upgraded, or new weapons, Kristensen said.

“It’s just a fundamentally different situation for the United States,” he said.

The U.S. now is modernizing its nuclear forces by creating a new gravity bomb, the B61-13, and new warheads to go on the upcoming LGM-35A Sentinel intercontinental ballistic missile and the Trident II D5 missile.

Part of that work will involve tests of the warheads’ critical subsystems, Erath said.

He said, though, that is it not necessary to go through the entire process and trigger the nuclear reactions that create devastating blasts to know whether the weapon will work.

“What happens after the plutonium goes critical is well known,” Erath said, “So you don’t need to do an explosive mushroom cloud-and-crater kind of nuclear test.

“You can do the smaller-scale subcritical testing, and that has been happening.”

Rattling a house of dynamite?

If the United States shatters the taboo against nuclear tests it helped create, other nations are sure to follow with their own tests, Erath said. Once that happens and they start to gather more detailed information on their own nuclear devices, he said, they will start to catch up to America.

It was not immediately clear what Trump was referring to when he referred to other nations’ testing programs.

In an interview with 60 Minutes that aired Sunday, Trump claimed without evidence that China and Russia have conducted clandestine nuclear weapons tests deep underground.

“Russia’s testing nuclear weapons and China’s testing them too,” Trump said. “You just don’t know about it. … You make nuclear weapons, and then you don’t test. How are you going to do that? How are you going to know if they work?”

China, which conducted its last known nuclear explosion in 1996, denied Trump’s claim. CBS reported that a Chinese Foreign Affairs Ministry spokeswoman told reporters Monday that China has “abided by its commitment to suspend nuclear testing,” and called on the United States to do the same.

In response to Trump’s comments, the AP reported Russian President Vladimir Putin on Wednesday ordered his nation’s defense and foreign ministries to analyze the United States’ intentions on nuclear testing and submit proposals for a resumption of Russia’s nuclear tests.

The only nation known to have conducted nuclear tests in the 21st century is North Korea, which detonated six devices underground between 2006 and 2017.

Russia announced Oct. 26 that it had successfully tested a cruise missile, called Burevestnik, that uses a nuclear-powered propulsion system and could carry a nuclear payload. Experts have played down Russia’s launch of the missile, saying Burevestnik’s technologies are not new and mainly geared toward intimidation and deterrence.

“Nuclear-powered cruise missiles are not innovative — the U.S. looked into this technology in the 1940s and 1950s, but ultimately decided that ballistic missiles were better at guaranteeing penetration of enemy defenses,” said William Alberque, who previously led a NATO analysis center devoted to arms control and nonproliferation.

Lukas Kulesa, director of proliferation and nuclear policy at the London-based Royal United Services Institute, said the Russian missile would not be effective for potential first or retaliatory strikes, primarily because it is slower than intercontinental ballistic missiles.

Meanwhile, Erath said it is possible the nuance of the difference between a nuclear-powered missile test and a nuclear weapon test was lost as word traveled through the White House.

“It’s not the actual nuclear weapon, it’s a delivery system – assuming it works, and that’s a big ‘if,’” Erath said.

The United States regularly conducts tests of its own nuclear-capable ICBMs, the Cold War-era Minuteman III, without nuclear warheads.

The latest test occurred early Tuesday morning, when an unarmed Minuteman III launched from Vandenberg Space Force Base in California and flew about 4,200 miles to a military test site in the Marshall Islands. An array of advanced sensors collected data throughout the missile’s terminal phase to determine if it performed correctly.

However, there is a significant difference between the two nations’ tests, Erath said.

The U.S. tests its ICBMs to maintain an effective nuclear deterrent and test its equipment, he said. Russia’s recent test, he said, was timed to ramp up pressure on the West over the Ukraine war.

“Russia was sending a message that they have nuclear capabilities and they’re not afraid to use them, in order to put more pressure [on allies] to resolve the Ukraine war, which is not going very well for Russia at present, … in such a way that will lock in Russian gains,” Erath said.

If the U.S. government were to proceed with full tests that explode nuclear weapons, Erath said, it would likely happen underground. That would minimize the environmental impact, he said, but not eliminate it entirely, because leaks can happen.

The diplomatic consequences and harm to nonproliferation efforts would be far more severe, Erath said. The United States would likely receive a storm of condemnation from other nations, he said.

With the global moratorium on nuclear weapons testing broken, Erath said, nations such as Russia, China, North Korea, India and Pakistan would likely follow Washington’s example.

“The dominoes would fall,” Erath said. “It would not be advantageous to U.S. foreign policy in any way.”

Kristensen agreed.

“They have comparatively more to gain from this than the United States,” Kristensen said.

“For countries like China, India and Pakistan, they have real interest in conducting more nuclear tests, because it would enable them to develop more advanced capabilities or check things they didn’t quite get to check the way they wanted to do when they did their nuclear test series.”

Kristensen said India and Pakistan, which are not believed to have perfected the two-stage thermonuclear bomb, would particularly benefit from a resumption of testing.

“They would absolutely start testing weapons,” Kristensen said.

Erath said he doubts a resumption of nuclear tests would simultaneously erode the taboo against using them against an enemy in war.

He said, though, that nuclear weapons are a tool of intimidation and that Moscow has repeatedly rattled its nuclear saber in recent years to discourage Western nations from providing more arms or other support to Ukraine. Russia in particular could use resumed nuclear tests to amplify its nuclear threats, he said.

Kristensen said the worldwide reaction to Trump’s social media post showed how volatile the issue is, and how care is needed when discussing it.

“This one ran around the world like a firestorm,” Kristensen said. “That helps indicate the severity of raising this issue. … If the United States were to go back on [its nuclear testing moratorium], that would have significant consequences around the world.”

Kristensen also noted that it took days after Trump’s post for Energy Secretary Wright to clarify what the nuclear testing would entail, and said Trump’s comments seem to have been made without advance coordination with government officials and agencies who could quickly address what the president meant.

“This kind of confusion and uncertainty undermines U.S. credibility with its allies,” Kristensen said. “They need to know if they can trust U.S. policies. … If the U.S. president now begins to signal that he’s interested in [nuclear testing] in some shape or form … it’s going to add to the pool of uncertainties [allies] have about what kind of partner the United States is now, and will be in the future.”

Carrying out these tests would also be difficult, Erath said, largely because the facilities designed to carry out such tests haven’t been used in more than three decades.

“They would need a lot of work and a lot of money to be made ready to test again,” Erath said. “That’s got to come from somewhere.”

Using money from preexisting nuclear modernization programs, Erath said, could, ironically, diminish U.S. military nuclear forces readiness.

He said it is hard to say how much getting nuclear test sites and equipment ready might cost but that it “would not surprise me if it topped a billion” dollars.

“Nuclear facilities don’t come cheap,” Erath said. “There’s a lot of specialized equipment involved that isn’t made anymore, so you’re going to have to reengineer some of that.”

Kristensen said he visited the former Nevada Test Site west of Las Vegas — now called the Nevada National Security Site — a few years ago and saw equipment used for tests decades ago, exposed to the elements out in the open and “rusty.”

“Behind a fence was equipment that used to be used in these instrumented tests,” Kristensen said. “Trailers where you would have the equipment and personnel, long, long, thick cables that were used to lower in [the warheads]. All this stuff would have to be replaced and geared toward this particular test.”

Replacing outdated or nonfunctioning measurement equipment would likely be expensive, he said.

Digging a hole deep enough for a nuclear bomb test would take months, Kristensen said — and finding the right digging equipment would be another challenge, since not many organizations have needed to dig such holes in the desert for a long time. Once the nuclear device is in there, it has to be sealed properly with materials such as gravel and concrete to keep radioactive materials from venting.

“They would have to build a whole tower over the hole in which they have this instrument package that would be lowered in there,” Kristensen said. “Those instruments would have to be designed by the nuclear laboratories to be able to do what it is that they want to record. There’s so many levels of this that have to fall into place.”

Elisabeth Gosselin-Malo in Milan contributed to this story.