It is actually rather simple: If the world wants to eliminate the threat of nuclear terrorism, it has to eliminate the fissile material—highly enriched uranium (HEU) or plutonium—that the terrorists would need to carry out such an attack. And the most vulnerable holdings of such material are likely to be in facilities like research reactors and commercial reprocessing plants rather than military compounds. Moving toward a world without weapons-usable material in the civilian realm is both possible and necessary.

Indeed, over the last few decades, and particularly since the September 11 attacks, the United States and the international community have taken some important steps in this regard. Thanks to US and Russian efforts and the two nuclear security summits initiated by President Obama, scores of research reactors have been converted from HEU to the safer low enriched uranium (LEU) used in nuclear power reactors; Russia has stopped producing plutonium in commercial reactors; and nearly two dozen countries have been “cleaned out” of dangerous fissile materials. Yet much more needs to be done.

Getting There
The first step is to broaden and deepen the effort to eliminate nonmilitary use of HEU. Diplomatically, that means taking advantage of international forums such as the Nuclear Security Summits—including a third scheduled for 2014 in the Netherlands—to internationalize a recent policy document from the Obama administration that calls for ending HEU civil use rather than merely minimizing it.

South Africa, Argentina, and Australia have taken steps to encourage companies to produce with LEU the rare isotopes used in medical diagnostics and treatment, and more countries need to follow their lead. Eliminating civilian use of HEU means pressuring some countries, such as Belarus, to end use of HEU in research reactors. More than 100 reactors around the world still use the dangerous material. And it calls for some countries that have ended their use of HEU to return their remaining stocks to their countries of origin (as Ukraine, Mexico, and Austria have done recently) to be converted to less dangerous LEU. Most crucially, it requires supporting Russia’s newfound willingness to convert its vast HEU-based civil infrastructure, and tackling the technical issues involved with more difficult conversions of facilities.

The Plutonium Challenge
If the challenge when it comes to eliminating HEU is to make more progress faster, the challenge when it comes to plutonium is to stop making things worse. More and more of this weapons-usable material is piling up around the world. According to the International Panel on Fissile Materials, as of January 2012, there were more than 256 tons of plutonium separated from nuclear power reactor fuel. Given that the International Atomic Energy Agency says only 8 kilograms of such material would be sufficient for a crude nuclear weapon, the current total is akin to tens of thousands of nuclear weapons. Yet the stockpile is still growing—it is 100 tons larger than it was just 15 years ago.

The stockpile continues to grow because countries like the United Kingdom, France, and Russia built up their reprocessing programs and separated tons of plutonium in the belief that uranium would be scarce and expensive, justifying the extra expense of making new fuel from the plutonium, and setting aside the grave security dangers involved. However, that has not proven to be the case. So the result is mountains of plutonium built on a shaky foundation.

A particularly egregious case is Japan. Tokyo continues to insist on advancing its plutonium reprocessing program and opening a massive new multibillion-dollar reprocessing facility even though it already has 44 tons of separated plutonium and no place to put recycled fuel now or in the future. Currently, no reactors in Japan use reprocessed fuel, and Tokyo has indicated that the country is likely to phase out the use of nuclear energy within the next few decades.

International meetings like the Nuclear Security Summits have been blocked from effectively addressing this issue because of the unwillingness of political leaders to challenge influential commercial reprocessors like Japan’s utilities, France’s Areva, and Russia’s Rosatom. But as President Obama said earlier this year, “the smallest amount of plutonium—about the size of an apple—could kill hundreds of thousands and spark a global crisis. We simply cannot go on accumulating huge amounts of the very material, like separated plutonium, that we are trying to keep away from terrorists.” Leaders must be willing to act on this concern at the 2014 summit in the Netherlands.

Finally, materials like cesium-137 and strontium-90 cannot produce the catastrophic damage of nuclear weapons, but terrorists could use them for dirty bombs or other means to produce mass panic, damage public health, and cause billions of dollars in commercial damage. Moving toward using these materials in less-dispersible, less-transportable forms and funding safer alternatives would be important contributions to a world without weapons-usable nuclear and radiological material.