WASHINGTON – Russia has likely been secretly carrying out nuclear tests with very low explosive power to help it upgrade its nuclear arsenal, according to a new US intelligence assessment that challenges Moscow’s claims that it is faithfully adhering to an international treaty banning nuclear tests.
The assessment, which was reported by The Wall Street Journal before being made public on Wednesday, marks the first time the US has said the Kremlin hasn’t strictly observed its commitments under the Comprehensive Nuclear Test Ban Treaty. It comes as the arms-control framework constraining military competition between the US and Russia has begun to crack and the two sides are pursuing ambitious programs to field new nuclear weapons.
An official at the Russian Embassy in Washington said his government strictly observes the provisions of all international treaties it has joined, including the nuclear test ban treaty, which Moscow ratified in 2000.
At issue are activities at Novaya Zemlya, a remote archipelago above the Arctic Circle where Russia conducts nuclear tests. There, Russia likely has tested nuclear weapons with very low yields, as part of its push to develop new nuclear weapons, US intelligence analysts said.
Negotiations for the Comprehensive Nuclear Test Ban Treaty, which bans nuclear test explosions of any size, concluded in 1996. The treaty hasn’t been ratified by enough countries to take effect, but the world’s major powers have agreed to abide by its terms.
The treaty allows a range of activities to assure the safety and reliability of nuclear weapons, including experiments involving fissile material, as long as they don’t produce a nuclear explosive yield.
“The United States believes that Russia probably is not adhering to its nuclear-testing moratorium in a manner consistent with the ‘zero yield’ standard,” Lt. Gen. Robert Ashley, the director of the US Defense Intelligence Agency, said in a speech on Wednesday at the Hudson Institute think tank in Washington.
Other administration officials declined to specify the size of the suspected Russian tests – whether they involve tiny blasts equivalent to the explosive power of a few pounds of TNT, or were substantially larger.
Appearing with Gen. Ashley at the Hudson Institute, Trump administration officials provided the vaguest of descriptions of the activities at the Russian nuclear-testing site.
“We believe they have the capability to do it, the way that they’re set up,” Gen. Ashley said.
Senior State Department official Thomas DiNanno said Russia is “probably engaged in that sort of testing,” citing Gen. Ashley’s remarks. Tim Morrison, of the National Security Council, said Russia had undertaken “actions,” not merely preparations, to improve its nuclear-weapons capabilities that run contrary to the zero-yield testing standard.
The US has been observing a moratorium on nuclear tests since 1992 and has said its experiments are designed to not produce a nuclear yield. The US was the first nation to sign the treaty but it never ratified it.
Groups favoring arms controls expressed concern that the administration might be exaggerating the still-classified evidence.
“The most effective way for the United States to enforce compliance with the zero-yield standard is for the US to ratify the treaty and help bring it into force, which would allow for intrusive, short-notice on-site inspections,” said Daryl Kimball, the executive director of the Washington-based Arms Control Association.
The new concerns about Russia’s adherence to the treaty come at a critical moment in arms control. In February, the Trump administration said it would withdraw from a treaty on intermediate-range nuclear forces, alleging Moscow had violated the agreement.
In February 2021, the US-Russian treaty reducing long-range nuclear arms is due to expire. The Trump administration is reviewing whether it will extend the accord, seek to modify it or jettison it altogether in favor of a new negotiating approach, a prospect that concerns arms-control advocates.
“The Comprehensive Test Ban Treaty, unratified though it is by the US but with 184 signatories, may be the last remaining cornerstone in the arms-control order,” said Steve Andreasen, who was the top National Security Council official on arms control during the Clinton administration.
The nuclear test ban agreement was the subject of sometimes difficult negotiations, a history that has a bearing on the question of whether Russia is acting in bad faith.
At first, the US, UK, France, China and Russia favored an agreement that would enable them to conduct low-yield nuclear explosive tests to maintain the viability of their nuclear arsenals.
But then-President Clinton later pressed for a ban on all nuclear tests, while allowing computer monitoring, certain types of nuclear experiments and other steps to maintain the safety and reliability of nuclear arsenals – as long as they didn’t produce a nuclear yield.
In drafting the treaty, the Clinton administration decided it was unnecessary and potentially problematic to try to negotiate a technical definition of the nuclear explosions that would be banned, US officials told Congress at the time.
But the US, UK, France, Russia and China exchanged still-confidential letters on the activities they agreed wouldn’t be prohibited, according to a June 18, 1997, presidential directive signed by Clinton that was that hasn’t been made public but was reviewed by the Journal.
Stephen Ledogar, the chief US negotiator on the treaty, told Congress in 1999 the Russians had been surprised by Clinton’s insistence on the zero-yield issue but had “slowly and painfully” agreed to it during the talks.
But the absence of a technical definition that spelled out what was a prohibited nuclear explosion led some members of a 2009 congressionally mandated commission on US nuclear strategy to question whether Russia and China had fully embraced the same zero-yield standard that was being observed by the US.
One important question is whether low-yield tests would be militarily significant. Siegfried Hecker, a former director of the government’s Los Alamos National Laboratory, said extremely low-yield tests – equivalent to a blast of 4 pounds of TNT or less – would help to assess the safety of nuclear weapons, but not to design new arms.
“It would be unfortunate if they were doing something at Novaya Zemlya that was not in the spirit of a zero-yield CTBT,” he said. “But would the Russians somehow be able to gain an advantage for new systems if they were doing something slightly more than that? My general sense is no.”
Without indicating their size, Gen. Ashley said the alleged tests at Novaya Zemlya could help the Russians design new weapons.
“Our understanding of nuclear-weapon development leads us to believe Russia’s testing activities would help it to improve its nuclear-weapons capabilities,” he said.