The decontamination of a site like Fukushima Daiichi isn't truly complete until the radioactive material from the site is safely disposed of. Spent nuclear fuel rods, for instance, remain dangerous for thousands of years after they've been removed from a power plant [source: U.S. EPA]. And while scientists and researchers are working tirelessly to find ways to neutralize the danger from the ever-growing amounts of nuclear waste generated every year, for now the only option we have is to store it. But where? After all, the volume of radioactive waste increases every second, with experts predicting the generation of an additional 400,000 tons (363,000 metric tons) over the next two decades [source: World Nuclear Association].
In the case of waste-emitting low-level radiation, the disposal process isn't markedly different from taking trash to the local landfill. While engineers have to be careful that such materials won't disperse under any circumstances or contaminate the local water supply, these disposal sites are typically located close to the surface.
Facilities designed to hold high-level radioactive waste, on the other hand, are much more robust. The Yucca Mountain facility in Nevada, for instance, cost more than $13 billion to construct and would store radioactive materials 1,000 feet (300 meters) underground in a network of shielded tunnels, but scientists and policy makers still debate its ability to safely contain its cargo [sources: Associated Press, Eureka County].
Constructing a nuclear waste repository is just the first step toward disposing of high level radioactive material. Next, the material must be placed into specially designed metal casks for transport. Because all manner of accidents can occur during transport, the casks are designed to withstand everything from 30-foot (9-meter) drops to 1475 degree Fahrenheit (802 degrees Celsius) fires [source: Eureka County]. These casks, constructed of stainless steel, titanium and other alloys, then make the journey from the site of origin to the nuclear waste repository where the casks can remain for thousands of years.
Not all countries choose to store high-level nuclear waste like the United States does, instead reprocessing the fuel and reusing it to generate more power. Still, reprocessing doesn't eliminate the need to store nuclear materials, making disposal a critical issue for every country using nuclear power
As you might imagine, cleaning up and disposing of nuclear waste is a costly endeavor. Britain's Nuclear Decommissioning Authority estimated the cost of cleaning up all 20 of the country's radioactive sites would top $160 billion, for instance [source: Macalister]. Still, proponents of nuclear energy say access to a reliable, clean and abundant energy source more than justifies the costs associated with maintaining and cleaning nuclear facilities.