New Fuel Source

Nuclear waste could be the new fuel source. There is a tantalizing amount of energy in all that nuclear waste that was slated to sit in Yucca Mountain for eons. Now that it won't be sitting there, some think it should be used. All of the electricity used by a typical American in a year can be generated by just three inches of one of the 14-foot rods of uranium dioxide used to power nuclear reactors. Yet when that rod, which has the diameter of a Bic pen, is "spent" and set aside as nuclear waste, less than 10% of the energy in the rod has been turned into electricity.

"Waste is just too gross of a term for it," says Sherrell Greene, director of Nuclear Technology at Oak Ridge National Laboratory. "I'm trying to get to the 90% of the fuel in that rod."

It's a difficult thing to do, but these days there's much more incentive to try. This spring the Obama administration effectively ended the long-tortured idea of storing the nation's spent nuclear fuel deep under Yucca Mountain in south-central Nevada. At the same time, the nation seems to be inching toward adding new nuclear reactors, creating more waste that we don't know what to do with. (When Yucca Mountain was conceived, it was assumed that the nuclear reactors in the United States would be shut down as they aged and not replaced.)

There is already a method used by countries like France and Japan to reprocess spent nuclear fuel. It has a long list of nasty problems associated with it, however. It's very expensive--the cost of uranium would have to jump by a factor of six to match the price of reprocessed fuel. Though reprocessing nuclear fuel shrinks the amount of waste, it doesn't eliminate it. And, worst of all, it results in the creation of plutonium, which could be used to make nuclear weapons.

For all of these reasons, the U.S., which invented the process as part of its nuclear weapons program in the 1940s and 1950s then pushed it as a recycling method up until the early 1970s, never built a reprocessing plant and has strongly discouraged other nations from doing so.

But the politics of reprocessing have been heating up. Pro-nuclear energy Sens. John McCain, R-Ariz., and Lamar Alexander, R-Tenn., pushed Energy Secretary Steven Chu on the issue in the spring. McCain and others suggest one big reason new nuclear reactors are not being built is the uncertainty around where the spent fuel is going to go.

In June, the House Science and Technology Committee held a hearing asking experts for suggestions about how reprocessing should be approached. Mark Peters, of Argonne National Laboratory, said that because the U.S. never invested in a big, current-generation reprocessing plant, the country has the opportunity to instead design and build a safer system.

The hope is that researchers can develop a method that extracts the usable portion of the spent fuel without isolating the plutonium. Left behind would be very poisonous nuclear waste, but waste that would degrade in tens of years instead of tens of thousands of years, making the need for very long-term storage less acute.

(When nuclear waste includes extremely radioactive elements, it is said to be "self-protecting"--the gamma rays that it emits would cook a person so fast that it's all but impossible to do something nefarious with it. Plutonium on its own, while very dangerous if inhaled, emits comparatively weak alpha radiation, which can be easily shielded.)

At Oak Ridge, Greene's team last year demonstrated a method by which it removed the uranium and the plutonium together. The team processed just 45 pounds of material, and Greene admits that they are far from proving it can be done on an industrial scale. "But it is now an established fact that we know a new set of processes to produce a new fuel without having to produce plutonium," he says. "It may very well be that it doesn't end up being the best method, but if there is one set of processes to do it, there are others. I'm confident we can find a way to do this."

Argonne National Laboratory has developed a method called pyroprocessing that uses molten salt to separate the materials instead of a water-based approach, like the methods used abroad and at Oak Ridge. Some so-called Generation IV nuclear reactors being researched eliminate the need for reprocessing or include pyroprocessing. And some suggest using nuclear fission to help transform nuclear waste into fuel. (See "Reinventing Nuclear Power.")

Many, though, are adamantly opposed to reprocessing. They argue that though some methods, new and old, do reduce the volume of waste, they actually complicate waste disposal by creating different types of radioactive waste. They also remain extraordinarily expensive. And while methods like the one being explored at Oak Ridge do protect the plutonium slightly, it's not nearly enough to eliminate the threat of proliferation.

"It's an oxymoron to talk about proliferation-resistant reprocessing," says Frank von Hippel, a physicist and professor of public and international affairs at Princeton University's Woodrow Wilson School. "Nobody has a good idea at the moment."

Another critic: John Holdren, Obama's science adviser, who argued against nuclear reprocessing in a 2003 paper.

In the meantime, nuclear waste in the U.S. is being stored at nuclear plants. The spent rods are cooled in pools of water for at least a year and then transferred to thick casks of steel and concrete.

No one seems to think this method is ideal, but both proponents and opponents of reprocessing agree that the method is acceptable for the next few decades. Which may give us time to either come up with better reactors or better reprocessing technologies.

"The vision in this country is that as long as we have nukes, we have an assumption that there will always be nuclear waste so we should learn to deal with it," says Oak Ridge's Greene. "Well, maybe there are other nuclear fuel cycles and reactors and processes that can minimize creation of problem."

(Source: www.forbes.com )