Last year, after the tsunami and reactor meltdown in Fukushima, Japan, many European nations decided to phase out their existing fleets of nuclear power plants. Germany and Belgium are aiming to end all atomic generation by 2030. Switzerland is shooting for 2035.

Not so easy to get rid of. (Jean-Pierre Clatot/AFP/GETTY IMAGES)

In a recent issue of New Scientist, Fred Pearce offered a handy step-by-step guide on how to take apart a nuclear reactor. There are thousands of tons of radioactive material to deal with — not just the spent fuel rods, but also various materials that have picked up lower levels of radioactivity. That includes, potentially, the reactor vessel, the fuel-rod casings, various bits of scrap metal and even old clothing. That waste can’t just be carted off to regular landfills; it needs to be disposed of properly. (Here’s a graphic breaking down the various types of waste.)

Very broadly speaking, there are three main ways (pdf) to decommission a nuclear reactor. The first option is to remove the fuel, disassemble the surrounding structure and find a safe place to store all the different radioactive bits. One problem with this option? Not every country in Europe currently has proper waste facilities set up, Pearce reports.

Alternatively, workers could simply take out the fuel, drain the plumbing and then lock up the reactor, letting the isotopes decay until the plant itself is less radioactive. After 10 to 80 years, the whole structure will be easier to dismantle. The third option, meanwhile, is to bury the reactor in a “tomb” of concrete and hope that no one cracks the structure open for the next 1,400 years. The U.S. Department of Energy took this approach for two old reactors at Savannah River in South Carolina.

All of these methods are time-intensive. As of 2012, some 138 nuclear reactors have been shut down (pdf) around the world, but only 17 have been fully decommissioned. It took England two full decades to finish its decommissioning of the Sellafield site after the nuclear reactor there was shut off in 1981.

What’s more, the process is costly: GlobalData estimates that it will cost at least $81 billion to decommission Europe’s reactors between now and 2030, with the biggest markets in France and Russia. Pearce suggests that some countries, such as Britain, may not currently have enough money budgeted for the task — in part because many of its reactors are custom-built and likely to cost more than expected to tear apart.

These sorts of headaches could be one reason why the United States is taking a different approach to its aging plants. The GlobalData report notes that U.S. utilities and regulators have announced plans to extend the lives of 71 nuclear reactors by another 20 years. Between now and 2030, only five U.S. commercial power reactors are expected to be decommissioned. (That’s in addition to the 28 commercial reactors that the United States has already shut down.)

Granted, the United States still has plenty of challenges — as Matthew Wald recently detailed for the New York Times, funds for decommissioning are lagging here, as well. But those problems are somewhat smaller than what Europe will be facing in the next two decades.