In September 2009, a group of masked men armed with automatic weapons and explosives arrived on the roof of a cash depot in Vastberg, Sweden in a helicopter. The men blasted their way through a skylight and hoisted millions of dollars up to the hovering aircraft — the operation took less than 20 minutes. When police rushed to respond they discovered a bag with the word “bomb” at their heliport — a diversion planted by the thieves — and caltrops (road spikes) near the depot to slow down their response on the ground. While many of the thieves were caught after an investigation, most of the money was never recovered.

The Vastberg heist was not a nuclear event, but a new report from my colleagues at Harvard University makes the case that the incident should have deeply troubling implications for the leaders from over 50 countries convening in the Netherlands on March 24-25 for a summit on nuclear security. The stark truth is that many locations around the world that store highly enriched uranium (HEU) and plutonium — the essential ingredients of nuclear weapons — would not be able to repel an attack from adversaries using tactics and weapons as sophisticated as those used by the Vastberg thieves. . An amount of plutonium that would fit in a soda can would be enough for terrorists to construct a crude nuclear bomb capable of reducing the heart of a major city to rubble (it wouldn’t require much HEU, either). Today, there are approximately 1440 tons of HEU and 500 tons of separated plutonium in hundreds of buildings in dozens of countries around the world; the theft of only .001 percent of this stockpile could lead to hundreds of thousands of deaths………

In the U.S. in 2012, an 82-year old nun and two other peace protestors broke into Y-12, a facility in Tennessee that contains the world’s largest repository of highly enriched uranium (HEU) in metal form and until the incident was colloquially known as “the Fort Knox of HEU” for its state-of-the-art security equipment. The nun bypassed multiple intrusion-detection systems because faulty cameras had not been replaced and guards at the central alarm station had grown weary of manually validating sensors that produced frequent false alarms.  When the protestors started hammering on the side of a building that contains enough HEU for hundreds of weapons, the guards inside assumed the noise was coming from construction workers that they had not been told were coming. She and her fellow protestors were eventually challenged by a single guard……….