Unbuilding an atomic giant

Inside the biggest nuclear power plant tear-down in the U.S.

Illustration by Adam Simpson

1. Cool it

At the San Onofre nuclear power plant, workers transfer 2,668 fuel assemblies—holding 1,109 metric tons of radioactive uranium-235—to 17-foot-tall stainless-­steel containers. These sit inside a deep, steel-lined cooling pool for several years, chilling at temperatures around 68 degrees Fahrenheit, until workers can move them to storage.

2. Entomb it

After the fuel cools, workers fit the canisters into 20-foot-deep concrete casks embedded in the ground. The concrete helps trap the fuel's radiation inside, while vents circulate air to keep it cool. These casks, which will be monitored and guarded around the clock, are strong enough to withstand earthquakes, tsunamis, even the impact of a jet crash.

3. Rip it

Remotely controlled tools cut up the highly contaminated equipment (less than .04 percent of the debris). Other robotic machines will remove the most tainted waste. Then workers—using hydraulic hammers, saws, and bulldozers—rip apart the buildings. Mundane office materials like shelving, furniture, and insulation fill out the junk pile.