Inside the country's biggest nuclear power plant tear-down

Unbuilding an atomic giant.

atomic giant

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.

4. Ship it

Demolition produces more than 25 million cubic feet of debris—rebar, concrete, and piping—enough to fill a decent-size college-­football stadium. The San Onofre site hosts up to 60 rail cars at a time, waiting to cart off the low-level radiation debris. Trucks haul the nontainted stuff—75 percent of the total—to landfills in Texas and Arizona.

5. Bury it

Freight cars carry the low-level radioactive debris—now packed in drums, bags, and large containers—to a nuclear-­waste landfill in the Utah desert. Workers there check and document radiation levels, then bury the stuff in "embankments," from 8 feet below grade to 38 feet above grade, in sedimentary rock and covered in clay and rock.

This article was originally published in the January/February 2018 Power issue of Popular Science.