For years, some scientists and policymakers have worried that the reliability of U.S. nuclear warheads could diminish as their plutonium components age. Such concerns have led some to argue the United States should resume nuclear testing, rebuild its older warheads, or both. Most recently, plutonium aging has been used by the Bush administration to justify an ambitious new proposal for remaking the weapons complex and the nuclear arsenal.

Think again. A new set of government studies finds that the plutonium primaries, or pits, of most U.S. nuclear weapons “will have minimum lifetimes of at least 85 years,” which is about twice as long as previous official estimates. The findings have led the National Nuclear Security Agency (NNSA) to admit that “the degradation of plutonium in our nuclear weapons will not affect warhead reliability for decades.” (Continue)