GLOWING, GLOWING, GONE: Because of the high radiation levels around the stricken Fukushima Daiichi nuclear power plant work must be done via remotely-operated machines and workers must wear full protective gear, including breathing apparatus. Image: Courtesy of TEPCO
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Twenty-five years after the tragic runaway fission and fire at Chernobyl, tons of concrete shield workers and visitors from the dangerously radioactive puddle of melted fuel that lurks in the basement of the building housing reactor No. 4. Similarly, more than 30 years after the partial meltdown at Three Mile Island in Pennsylvania, concrete shaved 2.5 centimeters deep guards a hollow reactor vessel, its partially melted down fuel rods having been taken out over the course of a decade and shipped to Idaho National Laboratory (INL) for study. And now, nearly two months after the serial partial meltdowns in the reactors and spent-fuel pools at Fukushima Daiichi, Tokyo Electric Power Co. (TEPCO) has announced at least nine months of work to control the nuclear accident—the initial part of a cleanup that could last for decades.
"It's like mining," says nuclear physicist Douglas Akers of INL of the Three Mile Island cleanup effort. "Go in and remove the previously molten fuel, pack it up in shipping containers, and remove it to Idaho."
What happens when nuclear reactors reach the end of their useful lives—either accidentally as in the cases above or as a planned shutdown for a series of power plants throughout the U.S. and the world, more and more in coming decades? The answer to that question ranges from a green field suitable for farming to sacrificial zones that, in effect, become nuclear parks, such as the 25-square-kilometer Rocky Flats National Wildlife Refuge in Colorado—a former bomb-making site—or the 30-square-kilometer "exclusion zone" surrounding Chernobyl, respectively.
"Today we know that about 77,000 square miles of territory in Europe and the former Soviet Union was contaminated with radioactive fallout, leaving long-term challenges for flora, fauna, water, the environment and human health," wrote Mikhail Gorbachev, the Soviet premier at the time of the Chernobyl explosion, in Bulletin of the Atomic Scientists's March/April 2011 issue. "Tens of billions of dollars have been spent in trying to contain and remediate the disaster," including a massive sarcophagus currently being constructed to re-entomb the melted radioactive fuel.
The cleanup at Fukushima Daiichi will face similar challenges, including ascertaining how much of the nuclear fuel melted down and how bad is the radioactive contamination on the power plant grounds—as well as in surrounding areas. That challenge is exacerbated by the fact that three reactors and two spent fuel pools have been affected by the crisis but are also surrounded by five further spent fuel pools and two more unaffected reactors—and the fact that the fuel rods remain uncooled even today. Step one will therefore be cooling the nuclear fuel, a process that could take at least three months per TEPCO's current plan, which involves entirely filling the stricken reactors with seawater—although leaks may foil this plan.