The plan on a hot summer day was to liquefy highly flammable lithium at a temperature of more than 750 degrees and then pump it into a special chamber for cooling, as part of a research project at Sandia National Laboratories in New Mexico. But what happened instead in August 2011 was a near-catastrophe that could easily have killed two workers. The experiment was designed to help learn more about lithium’s potential use in an advanced nuclear reactor. But it went awry when someone turned the wrong valve and the heater holding the lithium cracked, causing the molten liquid to leak and spray abruptly onto a pipe holding the coolant. The result was a steam explosion, a hydrogen explosion — or likely both — in the lab’s Plasma Materials Test Facility.
In mid-2013, four federal nuclear safety experts brought an alarming message to the top official in charge of America’s warhead production: Los Alamos National Laboratory, the nation’s sole site for making and testing a key nuclear bomb part, wasn’t taking needed safety precautions. The lab, they said, was ill-prepared to prevent an accident that could kill lab workers, and potentially others nearby. Some safety infractions had already occurred at the lab that year. But Neile Miller, who was then the acting head of the National Nuclear Security Administration in Washington, says those experts specifically told her that Los Alamos didn’t have enough personnel who knew how to handle plutonium so it didn’t accidentally go “critical” and start an uncontrolled chain reaction. Such chain reactions generate intense bursts of deadly radiation, and over the last half-century have claimed nearly two dozen lives.
Technicians at the government’s Los Alamos National Laboratory settled on what seemed like a surefire way to win praise from their bosses in August 2011: In a hi-tech testing and manufacturing building pivotal to sustaining America’s nuclear arsenal, they gathered eight rods painstakingly crafted out of plutonium, and positioned them side-by-side on a table to photograph how nice they looked. At many jobs, this would be innocent bragging. But plutonium is the unstable, radioactive, man-made fuel of a nuclear explosion, and it isn’t amenable to showboating. When too much is put in one place, it becomes “critical” and begins to fission uncontrollably, spontaneously sparking a nuclear chain reaction, which releases energy and generates a deadly burst of radiation. The resulting blue glow — known as Cherenkov radiation — has accidentally and abruptly flashed at least 60 times since the dawn of the nuclear age, signaling an instantaneous nuclear charge and causing a total of 21 agonizing deaths.