The March/April issue of the Bulletin of Atomic Scientists has an article (unfortunately behind a paywall) about the enormous stockpiles of plutonium and highly enriched uranium (HEU) the United States still retains for weapons purposes, co-authored by GSP Program Director Lisbeth Gronlund and myself. The article is based on chapter 6 of UCS’s recent report, Making Smart Security Choices, and concludes that the United States should immediately declare much more of this material excess and dispose of it in ways that minimize the risk that it could be stolen by terrorists and used to make a nuclear weapon.
After disposing of the material it has already declared excess to military requirements, the United States will still retain enough plutonium for around 10,000 nuclear weapons, and enough highly enriched uranium for 10,000 to 16,000 weapons. (All current U.S. nuclear weapons contain both plutonium and uranium, so these numbers are not cumulative.) The U.S. arsenal, while still much larger than needed, has now fallen to somewhat fewer than 5,000 deployed and reserve weapons. The United States should declare excess all fissile material above the amount needed for an arsenal of this size. This would mean declaring excess an additional 18 metric tons of plutonium and 135 metric tons of HEU. Although a small step, this would be consistent with President Obama’s pledge to move toward a world without nuclear weapons. To reduce the risk that terrorists will acquire nuclear materials, the United States should dispose of its excess plutonium directly, rather than by turning it into mixed-oxide (MOX) fuel to be used in commercial nuclear reactors. Before it is irradiated, MOX fuel does not contain the highly radioactive elements that make the spent fuel dangerous to handle, and the plutonium in the fuel can be separated by a straightforward chemical process, increasing security risks. On MOX, at least, the most recent federal budget request is a step in the right direction, placing the program into cold standby while evaluating alternative plutonium disposal methods.
Declaring additional weapons-usable fissile material excess and moving to dispose of it more quickly would benefit U.S. security by reducing the amount of this material that could fall into terrorist hands. It would have the added benefit of demonstrating that the Obama administration is still committed to its stated goal of reducing the number and role of U.S. nuclear weapons. In the case of fissile material, more is not better. Less—and quickly—would be.