U.S. Conducts Test Ban Verification Experiment

November 2023

A team led by the U.S. National Nuclear Security Administration (NNSA) conducted an experiment using chemical high explosives and radiotracers in an underground tunnel on Oct. 18 to “validate new predictive explosive models” to improve the U.S. ability to detect low-yield nuclear explosions around the world.

In a statement issued shortly after the experiment, Corey Hinderstein, NNSA deputy administrator for defense nonproliferation, said, “These experiments…will help reduce global nuclear threats by improving the detection of underground nuclear explosive tests.”

According to the NNSA, seismic data collected from such experiments are made available to researchers around the globe.

The experiment at the government’s former nuclear test site in Nevada took place as Russia announced that it would withdraw its ratification of the 1996 Comprehensive Test Ban Treaty (CTBT), which prohibits nuclear test explosions.

As reported by Interfax, the deputy speaker of Russia’s upper house of parliament, Konstantin Kosachyov, said on Oct. 20 that there should be an international assessment to determine whether the NNSA’s announced experiment was compliant with the CTBT. “We do not know what exactly the Americans have blown up underground,” he said.

In response to a question about the experiment, Russian Deputy Foreign Minister Sergei Ryabkov said on Oct. 20 that if the experiment was an underground explosion using chemical explosives and “if this information is true—it is presently being verified—this does not involve a nuclear weapons testing, and this blast does not contradict either the U.S. moratorium on nuclear tests or the provisions” of the CTBT.

Senior U.S. officials, including NNSA Administrator Jill Hruby, have said that they are open to working with others to develop a regime that would allow reciprocal observation with radiation detection equipment at each other’s subcritical nuclear experiments to allow confirmation that the experiment was consistent with the CTBT. To date, such a dialogue has not begun.—DARYL G. KIMBALL