In the wake of President Donald Trump’s announcement that the United States would test nuclear weapons “on an equal basis” with other countries, Secretary of Energy Chris Wright clarified this did not mean explosive tests.
“I think the tests we’re talking about right now are systems tests,” Wright said in the interview last week on Fox News. “These are not nuclear explosions. These are what we call noncritical explosions. So you’re testing all the other parts of the nuclear weapon to make sure they deliver the appropriate geometry.”
Wright is referring to subcritical, zero-yield experiments, where chemical explosives are used to shock nuclear materials like plutonium in a confined environment, but the quantity of nuclear material and the chemical release of the reaction is too small for a nuclear reaction to begin the way it would in a critical nuclear test. The national labs then collect data from the experiment and compare it to data from pre-1992 nuclear tests using supercomputers, like the ones NVIDIA and HPE are building for Los Alamos National Laboratory.
There should be “no worries” from the people in Nevada about seeing a “mushroom cloud” in the desert, Wright said, The tests would be on “new systems” instead of on nuclear weapons.
But the National Nuclear Security Administration (NNSA) already conducts subcritical experiments underground at Nevada National Security Site (NNSS). While the last publicly known subcritical experiments were done in May 2024, test site officials told the Exchange Monitor in December 2024 that the next subcritical experiment was slated for April 2025. The previous acting administrator of NNSA Teresa Robbins did not comment to the Monitor this year when asked whether the April 2025 experiment happened.
Meanwhile, in an interview on CBS’s 60 Minutes with Norah O’Donnell, Trump gave differing information to Wright. He said he wanted the U.S. to conduct tests on nuclear weapons for “denuclearization” purposes, and “to see how they work.” He also said Russia and China were doing tests that were not public knowledge.
When O’Donnell asked Trump why the U.S. needed to test nuclear weapons, Trump responded, “Russia announced that they were going to be doing a test. If you notice, North Korea’s testing constantly. Other countries are testing. We’re the only country that doesn’t test, and I want to be— I don’t want to be the only country that doesn’t test.”
When O’Donnell responded that “the only country that’s testing nuclear weapons is North Korea. China and Russia are not,” Trump said “Russia’s testing nuclear weapons— And China’s testing them too. You just don’t know about it.”
“That would be certainly very newsworthy,” O’Donnell said in response. “My understanding is what Russia did recently was test essentially the delivery systems for nuclear weapons, essentially missiles, which we can do that but not with nuclear warheads.” Trump just repeated that Russia and China were testing, and did not clarify whether the U.S. would be testing warheads or not.
Meanwhile, China’s foreign ministry responded in a press conference Monday that China, as a “responsible nuclear weapons state,” has always “upheld a self-defense nuclear strategy and abided by its commitment to suspend nuclear testing.” The ministry also said Beijing hopes the U.S. will “maintain global strategic balance and stability.”
The U.S. stopped testing nuclear weapons aboveground and underwater in 1963 through the Limited Test Ban Treaty, along with the U.K. and the then-Soviet Union. The U.S. has not tested nuclear weapons at full yield since 1992 in a self-imposed moratorium that roughly mirrors the provisions of the Comprehensive Test Ban Treaty, which Congress has not ratified.
China’s last publicly-known nuclear test was in 1996, and Russia’s was in 1990, though Moscow withdrew from the Comprehensive Test Ban Treaty in 2023. However, a 2022 report by the State Department accused Russia of conducting critical nuclear tests in violation of the zero-yield standard, and a 2019 Defense Intelligence Agency report made similar allegations. There have also been satellite images of Russia expanding its Novaya Zemlya nuclear facilities.