As U.S. President Donald Trump said he would resume nuclear testing, the U.S. Secretary of Energy stepped in personally, saying it was not a nuclear explosive test but a subcritical test.
U.S. Secretary of Energy Chris Wright defined the nature of the nuclear test Trump mentioned in a Reuters interview on the 2nd. Minister Wright said, "The test under discussion now is a system test," adding, "This is not a nuclear explosion, and it is what we call a subcritical explosion."
"Non-critical explosions" mean experiments that do not reach a critical state that triggers a nuclear fission chain reaction. It is closer to a performance test to check whether nuclear weapon components are working properly. Since signing the Comprehensive Nuclear-Test-Ban Treaty (CTBT) in 1992, the United States has steadily conducted subcritical tests. According to the Department of Energy, there are clear differences in how they are conducted compared with experiments involving actual nuclear explosions. Experts assessed that the energy minister personally dialed back Trump's bombshell remarks and added explanations to minimize diplomatic fallout.
On the 30th, after a summit with Chinese President Xi Jinping, President Trump strongly hinted at the possibility of resuming nuclear testing on his way home. Before boarding his presidential plane (Air Force One) at Gimhae Air Base in Busan, he met with reporters and said, "With other countries conducting (nuclear) tests, I think it is appropriate for us to do so as well." He also hinted at plans to restart a nuclear test site, saying, "We have a nuclear test site, and (an actual test plan) will be announced."
His remarks about nuclear testing came just one hour after the meeting with Xi ended. Because of this, some interpreted them as a strong pressure message toward China and Russia. In fact, immediately after Trump's comments, Russia and China moved to respond strongly. Kremlin spokesperson Dmitry Peskov warned, "If anyone violates the declaration halting nuclear tests, Russia will take corresponding measures." China's Ministry of Foreign Affairs also treated nuclear nonproliferation as a serious issue on par with the "one China" principle. Ministry of Foreign Affairs Spokesperson Guo Jiakun urged the United States to uphold the international nuclear disarmament regime.