Highly enriched uranium (HEU) is usually regarded as the fissile material most desirable to terrorists, given the relative ease with which it could be used to manufacture a simple nuclear explosive device. For similar reasons, it’s also worrisome from a state-level proliferation viewpoint.

Highly enriched uranium (HEU) is usually regarded as the fissile material most desirable to terrorists, given the relative ease with which it could be used to manufacture a simple nuclear explosive device. For similar reasons, it’s also worrisome from a state-level proliferation viewpoint.

But thanks in part to U.S. leadership, a diverse and increasing number of countries now recognize the risks associated with the civilian use, storage, and trade in HEU and have taken steps to reduce their reliance upon this dangerous material. In fact, an international scientific consensus agrees that there is no technical reason to continue to use HEU in research reactors, in medical isotope production, or in other civilian applications.

What is clear is that without an international norm of some sort, phasing out the use of HEU in the civilian sector will prove to be quite difficult.”

Nonetheless, political and economic obstacles continue to hamper efforts to achieve a global clean out of civilian HEU, despite the Obama administration’s plans to sharply increase spending in pursuit of such an objective. In fact, nearly 800 kilograms of HEU continue to be used annually in research reactors and to produce medical isotopes–enough for 40 Hiroshima-type bombs.

The obstacles vary from Russian fears that parting with such material will reduce the prestige of the country’s research facilities to South African objections that calls for non-nuclear weapon states to part with their HEU is “disarming the disarmed” to Canadian concerns that converting domestic medical isotope production facilities to less dangerous low-enriched uranium (LEU) targets will cost too much.

A consistent theme is a sense of complacency about the danger posed by HEU stockpiles, with many developing countries in particular attaching little urgency to U.S. concerns about nuclear terrorism. What is clear is that without an international norm of some sort, phasing out the use of HEU in the civilian sector will prove to be quite difficult.

To be sure, some steps forward have been taken in recent years. U.N. Security Council Resolution 1887, adopted unanimously last fall, calls upon all states to “manage responsibly and minimize to the greatest extent that is technically and economically feasible the use of highly enriched uranium for civilian purposes, including by working to convert research reactors and radioisotope production processes to the use of low enriched uranium fuels and targets.”

Unfortunately, this phrasing, although politically necessary to win support from countries such as France and Russia, doesn’t attach much urgency to HEU elimination. Moreover, although the HEU provision hasn’t received much attention in and of itself, the resolution as a whole has been criticized by many developing countries as inappropriate “legislating” by the U.N. Security Council.

President Barack Obama’s upcoming Nuclear Security Summit will likely endorse some form of HEU minimization, but almost certainly with a caveat regarding economic and technical feasibility. The Obama administration should also use the occasion to encourage countries to sign a voluntary code of conduct in relation to HEU. Such a code could be adopted by countries, nuclear operators, universities, and other stakeholders.

A potential code drafted by the James Martin Center for Nonproliferation Studies and already supported by some governments would commit its adherents to:

Eliminating or converting installations from HEU to LEU as soon as technically feasible;

Ending transfers of HEU except on an interim basis to facilities actively pursuing conversion to LEU;

Maintaining security at levels concomitant with the risks;

Undertaking activities that would help make conversion possible; and

Developing and maintaining a strategy for the management and eventual elimination of HEU.

Taken together, adoption in the final summit communique of such a code and a commitment to HEU reduction (and eventual elimination) in the civilian sector represents a major step forward in reducing the danger of terrorists acquiring crude, but real, nuclear explosives.

Editor’s note: The coauthors of this column are William Potter, the director of the James Martin Center for Nonproliferation Studies, and Miles A. Pomper, a senior research associate at the center.