By Guy Faulconbridge and Anastasia Teterevleva
MOSCOW (Reuters) -Russia's lower house of parliament on Wednesday approved a move to withdraw from a landmark agreement with the United States aimed at reducing vast stockpiles of weapons-grade plutonium left over from thousands of Cold War nuclear warheads.
The Plutonium Management and Disposition Agreement (PMDA), signed in 2000, committed both the United States and Russia to dispose of at least 34 tonnes of weapons-grade plutonium each, which U.S. officials
said would have been enough for as many as 17,000 nuclear warheads. It came into force in 2011.
"The United States has taken a number of new anti-Russian steps that fundamentally change the strategic balance that prevailed at the time of the Agreement and create additional threats to strategic stability," a Russian note on the legislation withdrawing Moscow from the pact said.
After dismantling thousands of warheads after the Cold War, both Moscow and Washington were left with huge stockpiles of weapons-grade plutonium which was costly to store and posed a potential proliferation risk.
The aim of the PMDA was to dispose of the weapons-grade plutonium by converting it into safer forms - such as mixed oxide (MOX) fuel or by irradiating plutonium in fast-neutron reactors for electricity production.
Russia in 2016 suspended implementation of the agreement, citing U.S. sanctions and what it cast as unfriendly actions against Russia, NATO enlargement and changes to the way the United States was disposing of its plutonium.
Russia said at the time that the United States had not abided by the agreement after Washington moved, without Russian approval, to simply diluting the plutonium and disposing of it.
Russia and the United States are by far the world's biggest nuclear powers, and together they control about 8,000 nuclear warheads, though far less than the peak of 73,000 warheads in 1986, according to the Federation of American Scientists.
(Reporting by Guy Faulconbridge and Anastasia TeterevlevaEditing by Andrew Osborn)
