On 27 October 2025 the President of Russia signed a federal law that denounced the US-Russian Plutonium Management and Disposition Agreement. This law ended another chapter in the history of US-Russian cooperation. The factual account, with links to documents, is on the IPFM blog. I will mention two important points here, though.

One is that the obligation not to use the PMDA material (which is 34 tonnes of weapons-grade plutonium) for any military purpose remains in place. When Russia suspended its participation in the PMDA in 2016, it did so by a presidential decree that clearly stated that the PMDA material "shall not be used for the purposes of manufacturing nuclear weapons or other nuclear explosive devices, for research, development, design, or testing related to such devices, or for any other military purposes."

The denunciation law did not revoke this obligation and we should assume that it is still in force unless a new presidential decree revokes the 2016 one. But, of course, the real reason we can be certain that neither Russia nor the United States will use PMDA material for weapons is that they don't need to -- they have much more weapons-grade plutonium than they know how to use.

Another point worth making is that even though it may seem insignificant--who cares about PMDA plutonium?--the way the United States handled the PMDA did a lot of damage to the US-Russian relations. Back in the day, I wrote an article in the Bulletin of the Atomic Scientists where I tried to describe the problem. In brief, the PMDA is one of the (relatively) rare cases when the US was at fault for violating an agreement. When the United States decided to change the plutonium disposition method, it decided that it did not want to wait for Russia's explicit approval despite a clear requirement to do so. Russia didn't really care about the plutonium, but it had reasons to be concerned about this disregard of a legally binding obligation. Where is the respect of your treaty obligations when you need it?

Image: A mock-up of a container that is used to store weapon-origin plutonium at the Mayak Plant Fissile Material Storage Facility.