For its part, the US Energy Department, which owns almost 50 tons of excess Cold War plutonium, contracted with the French government-owned nuclear-fuel cycle company, Areva (now Orano), in 2008 to build a MOX fuel fabrication plant. But the United States switched to a “dilute and dispose” policy for its excess plutonium in 2017 after the estimated cost of the MOX plant grew from $2.7 billion to $17 billion.