Nuclear security

As Putin Swipes At U.S. Over Plutonium Disposal, Nuclear Cooperation Takes A Hit

Plutonium has been produced in the United States and Russia for decades. In its enriched form, it is valued as fuel for nuclear weapons; in a less-pure state, it can be used to fuel power plants.

The two countries together hold the world’s largest stockpiles. The most recent inventory by the U.S. Energy Department showed the United States had around 95 tons, most of which was weapons grade.

Russia, for its part, is estimated to have around 128 tons of weapons-grade plutonium.

In 2010, Moscow and Washington recommitted themselves to a deal signed a decade earlier called the Plutonium Management and Disposition Agreement.

That deal, which was negotiated in the 1990s, called for turning a chunk, though not all, of the countries’ weapons-grade plutonium stockpiles into other forms, such as fuel for nuclear power plants.

Though the amount involved was just a fraction of the overall stockpiles -- 34 tons -- the deal has been widely viewed as a barometer of U.S.-Russian nuclear cooperation.