testing

Nov. 6 (UPI) — President Donald Trump’s calls to ramp up nuclear weapons testing last week have put nuclear watchdogs and world leaders on alert while experts say the United States has little to gain.

In a post on Truth Social on Oct. 29, Trump said he is ordering the Department of Defense to immediately begin testing nuclear weapons “on an equal basis.” What this means remains unclear, though Energy Secretary Chris Wright said in an appearance on FOX News these would not be full-scale explosive tests.

“These are not nuclear explosions,” Wright said. “These are what we call non-critical explosions.”

The comment by Wright echoes the stance Brandon Williams, under secretary of energy for Nuclear Security in the Department of Energy, shared during his Senate confirmation hearing in May. Williams said testing nuclear weapons above the criticality threshold would not be advisable.

According to the International Campaign to Abolish Nuclear Weapons and Nuclear Weapons Ban Monitor, the United States possesses more than 5,000 nuclear weapons. It has performed 1,054 explosive nuclear tests, more than any other country.

The type of testing the president is calling for is an important distinction to make, Dylan Spaulding, senior scientist for the Union of Concerned Scientists, told UPI. The delivery systems of nuclear weapons and the components of the weapons are commonly tested.

Subcritical tests are also performed. These are tests that do not yield a sustained nuclear reaction that would cause an explosion.

“He did mention testing on an equal basis,” Spaulding said. “If that’s the case, in fact the United States already does conduct all the kinds of tests of our nuclear delivery systems and even the components of the weapons themselves that other countries do.”

The United States and most of the rest of the world, aside from North Korea, have refrained from full-scale nuclear weapons testing for more than 30 years. In 1993, the United States signed a unilateral moratorium on explosive testing under the Comprehensive Nuclear Test Ban Treaty.

Breaking from the treaty is likely to open the door to escalation in the form of other countries, including adversaries like China and Russia, openly testing nuclear explosives, Henry Sokolski, executive director of the Nonproliferation Policy Education Center, told UPI.

“What if those countries decided that maybe this is a cue for them to test?” Sokolski said. “Would that provoke any of the larger states that signed [the treaty] but didn’t ratify to test?”

The only country to break from the agreement in this treaty is North Korea, conducting six nuclear tests concluding in 2017.

Sokolski argues that the United States has the least to gain by breaking the moratorium and setting off a precedent for open nuclear weapons testing. The United States’ research in the field is extensive, beyond that of any other country. Other countries, such as Russia, China, India, Pakistan and North Korea stand to benefit the most from more explosive research while the United States would likely gain little more knowledge.”

“I spend a lot of time talking to weapons designers about this. You don’t test for reliability testing generally,” Sokolski said. “That requires 10 to 20 datapoints. That means 10 to 20 tests of each design. That seems kind of wasteful. You don’t design to prove things you’ve already proven.”

“If you’re doing a design that is totally radical, that’s something different, but we’re not,” he continued. “We’re fiddling with yield-to-weight ratios. There are countries like Israel who have tested once, in 1979, one test. Are you telling me their stockpile is unreliable and doesn’t work? If you want to make weapons you can do it very cheaply and quickly without testing.”

Spaulding agrees that full-scale testing is not necessary, adding that scientists continue to analyze data from the repository of the United States’ nuclear weapons testing history.

“We are still learning from those underground tests,” he said. “Other countries don’t have that advantage right now but we would be essentially giving them permission to catch up by returning to testing.

The argument for more live-testing of nuclear weapons capabilities is that it can insure and assure that the stockpile of weapons is reliable.

The United States has the Stockpile Stewardship Program that already tests the reliability and safety of its nuclear weapons. Daryl Kimball, executive director of the Arms Control Association, told UPI the scientific community is “very confident” in the program.

While the United States is one of only nine countries that have not ratified the treaty, it is legally bound as a signatory to not violate the object or purpose of the agreement, Kimball said. He is doubtful that this will deter Trump.

Of the 1,054 explosive nuclear tests performed by the United States, 928 have been conducted at the Nevada Nuclear Site in south-central Nevada about 65 miles outside of Las Vegas. The site is the only candidate for hosting further nuclear testing, according to experts.

The last explosive test was conducted in 1992 before the United States began observing the international moratorium.

Past tests at the site yielded observable health and environmental impacts on residents of the region and beyond.

“Anyone born in ’63 or earlier, they were exposed to some level of strontium 90, which was showing up in the baby teeth of American children in the 50s and 60s,” Kimball said. “It accumulates in the teeth because you drink milk and it gets concentrated in the teeth.”

The United States joined the Soviet Union and United Kingdom in the Limited Test Ban Treaty in 1963, in part because of the baby teeth study. The treaty banned nuclear weapons testing in the atmosphere, outer space and underwater.

Subjects of the baby teeth study were children in the St. Louis area, more than 1,600 miles from the Nevada nuclear test site.

With the atmospheric testing ban in place, explosive testing was moved underground in deep boreholes. This was meant to limit nuclear fallout, lessening environmental and health implications.

The vertical testing shafts are reinforced to limit geological impacts but the powerful explosions still generate fractures in the earth and the leakage of radionuclides, a hazardous radioactive material.

People who lived downwind of the Nevada test site, known as downwinders, have experienced higher than average rates of cancer.

“These downwinders, in their second generation, they’re still suffering from some of these adverse health effects,” Kimball said. “They are particularly angry. Trump’s announcement is a slap in the face to them as they see it. They want to see all forms of testing, above and below ground, concluded.”

Restarting full-scale testing would be no small task, Sokolski said. What he refers to as a “quick and dirty” test, one that provides an explosion but little in the way of research, would take months and millions of dollars to prepare.

“To get data, depending on how much data, we could be talking about one to two years and much, much more money, maybe approaching a higher order of magnitude, a billion [dollars],” Sokolski said. “Those stumbling blocks are the ones of interest.”

ABOARD AIR FORCE ONE — President Trump declined to say Friday whether he plans to resume underground nuclear detonation tests, as he had seemed to suggest in a social media post this week that raised concerns the U.S. would begin testing nuclear weapons for the first time in three decades.

The president told reporters “You’ll find out very soon,” without elaborating when asked if he means to resume underground nuclear detonation tests.

Trump, who spoke to reporters aboard Air Force One as he headed to Florida for a weekend stay, said, “We’re going to do some testing” and “Other countries do it. If they’re going to do it, we’re going to” but then refused to offer more details.

His comments on nuclear testing have drawn confusion inside and outside the government when the president seemed to suggest in a brief post that the U.S. would resume nuclear warhead tests on an “equal basis” with Russia and China, whose last known tests were in the 1990s. Some of Trump’s comments seemed to refer to testing missiles that would deliver a warhead, rather than the warhead itself. There has been no indication that the U.S. would start detonating warheads.

The U.S. military already regularly tests its missiles that are capable of delivering a nuclear warhead, but it has not detonated the weapons since 1992. The Comprehensive Nuclear Test Ban Treaty, which the U.S. signed but did not ratify, has been observed since its adoption by all countries possessing nuclear weapons, North Korea being the only exception.

The Pentagon has not responded to questions. The Energy Department, which oversees the U.S. nuclear stockpile, declined to comment Friday.

Trump’s post on nuclear tests came as Russia this week announced it had tested a new atomic-powered and nuclear-capable underwater drone and a new nuclear-powered cruise missile.

Russia responded to Trump’s post by underscoring that it did not test its nuclear weapons and has abided by a global ban on nuclear testing. The Kremlin warned though, that if the U.S. resumes testing its weapons, Russia will as well — an intensification that would restart Cold War-era tensions.

Vice Adm. Richard Correll, Trump’s nominee to lead the military command in charge of the nation’s nuclear arsenal, struggled to interpret the president’s comments when he testified before senators during a Capitol Hill hearing Thursday, telling them, “I’m not reading anything into it or reading anything out of it.”

Price and Ceneta write for the Associated Press. Price reported from Washington.

Tehran rebukes US plans for nuclear tests, citing hypocrisy over peaceful nuclear programme accusations.

Iranian Foreign Minister Abbas Araghchi has condemned calls by United States President Donald Trump for the Pentagon to resume nuclear weapons testing, calling the move both “regressive” and irresponsible”.

“Having rebranded its ‘Department of Defense’ as the ‘Department of War,’ a nuclear-armed bully is resuming testing of atomic weapons,” Araghchi wrote in a post on X late Thursday.

“The same bully has been demonising Iran’s peaceful nuclear program and threatening further strikes on our safeguarded nuclear facilities, all in blatant violation of international law,” he said.

Trump made the surprise announcement in a Truth Social post on Thursday shortly before meeting with Chinese President Xi Jinping in South Korea on the sidelines of the Asia-Pacific Economic Cooperation (APEC) summit.

Trump said he had instructed the Pentagon to immediately resume nuclear weapons testing “on an equal basis” with other countries like Russia and China, whose nuclear weapons arsenal will match the US in “five years”, according to Trump.

Ankit Panda, a nuclear security expert and senior fellow at the Carnegie Endowment for International Peace, told Al Jazeera that Trump’s decision was likely a response to recent actions by Russia and China rather than Washington’s ongoing dispute with Iran over its nuclear programme.

Russian President Vladimir Putin announced this week that Moscow had tested its Poseidon nuclear-powered super torpedo, after separately testing new Burevestnik nuclear-powered cruise missiles earlier in the month, according to the Reuters news agency.

China also recently displayed its nuclear prowess at a military parade in September, which featured new and modified nuclear weapons systems like the Dongfeng-5 nuclear-capable intercontinental ballistic missile.

Having rebranded its “Department of Defense” as the “Department of War”, a nuclear-armed bully is resuming testing of atomic weapons. The same bully has been demonizing Iran’s peaceful nuclear program and threatening further strikes on our safeguarded nuclear facilities, all in… pic.twitter.com/ft4ZGWnFiw

— Seyed Abbas Araghchi (@araghchi) October 30, 2025

Despite these public displays of firepower, neither Russia nor China has carried out a nuclear test – defined as a nuclear explosion above ground, underground, or underwater – in decades, according to the United Nations.

Nuclear testing is banned by the Comprehensive Nuclear Test-Ban-Treaty of 1996. The US, China, and Iran all signed but have not ratified the original treaty, while Russia withdrew its ratification in 2023.

Moscow carried out its last nuclear test in 1990 while still the Soviet Union, and China carried out its last nuclear test in 1996, according to the UN. The last nuclear test by the United Kingdom was in 1991, followed by the US in 1992 and France in 1996. North Korea is the only country that has carried out nuclear tests in the past two decades, with its last test in 2017.

Trevor Findlay, a nuclear security expert and honorary professional fellow at the University of Melbourne, told Al Jazeera that it was unclear what type of testing Trump was referring to in his post.

“My assumption is that he means missile launches of nuclear-capable missiles, as North Korea and Russia have been doing very publicly. These do not carry an actual nuclear warhead [but likely a dummy], nor do they create a nuclear explosion,” he said.

“The US already tests its own missiles periodically, both existing ones and ones in development, often splashing down in the Pacific. It does announce them but tends not to make a big deal of it, like North Korea and Russia,” he said.

Trump, meanwhile, has called for the “total dismantlement” of Iran’s nuclear programme and says he does not want Tehran to obtain a nuclear weapon. In June, the US and Israel also carried out air strikes on Iranian military and nuclear facilities in part to slow its progress.

Tehran has maintained that its nuclear programme is for civilian purposes only, and it has never carried out a nuclear test, according to the Carnegie Endowment’s Panda.

“Iran has never done any nuclear tests. They’ve constantly been saying they are not intending to make a nuclear bomb,” Panda told Al Jazeera. “The only thing that Iran has which might be taken seriously is some highly enriched uranium. That’s it. They have not even tested a nuclear ballistic missile.”

DUBAI, United Arab Emirates — President Trump’s comments Thursday suggesting the United States will restart its testing of nuclear weapons upends decades of American policy in regards to the bomb, but come as Washington’s rivals have been expanding and testing their nuclear-capable arsenals.

Nuclear weapons policy, once thought to be a relic of the Cold War, increasingly has come to the fore as Russia has made repeated atomic threats to both the U.S. and Europe during its war on Ukraine. Moscow also acknowledged this week testing a nuclear-powered-and-capable cruise missile called the Burevestnik, code-named Skyfall by NATO, and a nuclear-armed underwater drone.

China is building more ground-based nuclear missile silos. Meanwhile, North Korea just unveiled a new intercontinental ballistic missile it plans to test, part of a nuclear-capable arsenal likely able to reach the continental U.S.

The threat is starting to bleed into popular culture as well, most recently with director Kathryn Bigelow ‘s new film “A House of Dynamite.”

But what does Trump’s announcement mean and how would it affect what’s happening now with nuclear tensions? Here’s what to know.

Trump’s comments came in a post on his Truth Social website just before meeting Chinese leader Xi Jinping. In it, Trump noted other countries testing weapons and wrote: “I have instructed the Department of War to start testing our Nuclear Weapons on an equal basis. That process will begin immediately.”

The president’s post raised immediate questions. America’s nuclear arsenal is maintained by the Energy Department and the National Nuclear Security Administration, a semiautonomous agency within it — not the Defense Department. The Energy Department has overseen testing of nuclear weapons since its creation in 1977. Two other agencies before it — not the Defense Department — conducted tests.

Trump also claimed the U.S. “has more Nuclear Weapons than any other country.” Russia is believed to have 5,580 nuclear warheads, according to the Washington-based Arms Control Association, while the U.S. has 5,225. Those figures include so-called “retired” warheads waiting to be dismantled.

The Stockholm International Peace Research Institute further breaks the warhead total down, with the U.S. having 1,770 deployed warheads with 1,930 in reserve. Russia has 1,718 deployed warheads and 2,591 in reserve.

The two countries account for nearly 90% of the world’s atomic warheads.

U.S. last carried out a nuclear test in 1992

From the time America conducted its “Trinity” nuclear bomb detonation in 1945 to 1992, the U.S. detonated 1,030 atomic bombs in tests — the most of any country. Those figures do not include the two nuclear weapons America used against Japan in Hiroshima and Nagasaki at the end of World War II.

The first American tests were atmospheric, but they were then moved underground to limit nuclear fallout. Scientists have come to refer to such tests as “shots.” The last such “shot,” called Divider as part of Operation Julin, took place Sept. 23, 1992, at the Nevada National Security Sites, a sprawling compound some 65 miles from Las Vegas.

America halted its tests for a couple of reasons. The first was the collapse of the Soviet Union at the end of the Cold War. The U.S. also signed the Comprehensive Nuclear Test-Ban Treaty in 1996. There have been tests since the treaty, however — by India, North Korea and Pakistan, the world’s newest nuclear powers. The United Kingdom and France also have nuclear weapons, while Israel long has been suspected of possessing atomic bombs.

But broadly speaking, the U.S. also had decades of data from tests, allowing it to use computer modeling and other techniques to determine whether a weapon would successfully detonate. Every president since Barack Obama has backed plans to modernize America’s nuclear arsenal, whose maintenance and upgrading will cost nearly $1 trillion over the next decade, according to the Congressional Budget Office.

The U.S. relies on the so-called “nuclear triad” — ground-based silos, aircraft-carried bombs and nuclear-tipped missiles in submarines at sea — to deter others from launching their weapons against America.

Restarting testing raises additional questions

If the U.S. restarted nuclear weapons testing, it isn’t immediately clear what the goal would be. Nonproliferation experts have warned any scientific objective likely would be eclipsed by the backlash to a test — and possibly be a starting gun for other major nuclear powers to begin their own widespread testing.

“Restarting the U.S. nuclear testing program could be one of the most consequential policy actions the Trump administration undertakes — a U.S. test could set off an uncontrolled chain of events, with other countries possibly responding with their own nuclear tests, destabilizing global security, and accelerating a new arms race,” experts warned in a February article in the Bulletin of Atomic Scientists.

“The goal of conducting a fast-tracked nuclear test can only be political, not scientific. … It would give Russia, China and other nuclear powers free rein to restart their own nuclear testing programs, essentially without political and economic fallout.”

Any future U.S. test likely would take place in Nevada at the testing sites, but a lot of work likely would need to go into the sites to prepare them given it’s been over 30 years since the last test. A series of slides made for a presentation at Los Alamos National Laboratories in 2018 laid out the challenges, noting that in the 1960s the city of Mercury, Nevada — at the testing grounds — had been the second-largest city in Nevada.

On average, 20,000 people had been on site to organize and prepare for the tests. That capacity has waned in the decades since.

“One effects shot would require from two to four years to plan and execute,” the presentation reads. “These were massive undertakings.”

Gambrell writes for the Associated Press.

For the first time since Russia’s full-scale invasion of Ukraine, a NATO member has formally invoked Article 4 of the alliance’s founding treaty after a major airspace breach. Estonian Foreign Minister Margus Tsahkna tells Talk to Al Jazeera why repeated Russian provocations are more than isolated incidents – they’re a test of NATO’s credibility. As United States President Donald Trump questions the value of collective defence, Tsahkna warns that Europe’s security consensus is fraying and hesitation could invite danger.