Last October, at the foot of a rocky hillside near here, at a spot known as Degelen Mountain, several dozen Kazakh, Russian and American nuclear scientists and engineers gathered for a ceremony. The modest ribbon-cutting marked the conclusion of one of the largest and most complex nuclear security operations since the Cold War — to secure plutonium (enough to build a dozen or more nuclear weapons) that Soviet authorities had buried at the testing site years before and forgotten, leaving it vulnerable to terrorists and rogue states. The effort spanned 17 years, cost $150 million and involved a complex mix of intelligence, science, engineering, politics and sleuthing. This op-ed is based on documents and interviews with Kazakh, Russian and U.S. participants, and reveals the scope of the operation for the first time.

The Belfer Center’s Eben Harrell and Pulitzer Prize-winning author David E. Hoffman for the first time report the details of one of the largest nuclear security operations of the post-Cold War years — a  secret 17-year, $150 million operation to secure plutonium in the tunnels of Degelen Mountain.

In the past two decades, at least two terrorist groups have made serious attempts at obtaining nuclear weapons or the nuclear material needed to make them. They won't be the last. Foiling terrorists willing to inflict unlimited damage requires the international community to prioritize the nuclear stocks that pose the greatest risks and take immediate steps to eliminate or secure them.

The United States and Russia possess 95% of the world’s nuclear weapons and most of the world’s weapons-usable nuclear material, and so bear a special responsibility for preventing nuclear terrorism. Unfortunately, both countries missed an opportunity in Seoul – neither committed to major new steps to strengthen nuclear security at home beyond the steps they were already taking, nor did they announced any new joint initiatives. That must change.

Following the 2012 Nuclear Security Summit in Seoul, South Korea, Associate Professor Matthew Bunn answered questions from Research Associate Eben Harrell about the successes of the summit and the remaining challenges.

Leaders at the 2010 nuclear security summit agreed on the goal of securing all vulnerable nuclear material in four years, but the factors that drive and/or constrain nuclear security changes are not well understood. Matthew Bunn and Eben Harrell surveyed nuclear security professionals in countries with nuclear weapons, HEU, or separated plutonium to explore this issue. This paper describes the survey, its results, and implications for strengthening global nuclear security.