Metal oxide material for electrorefining is being tested by chemist Laurel Barnes in a glove box.

Argonne’s spent-fuel recycling may reduce nuclear waste storage shortage

Argonne’s spent-fuel recycling may reduce nuclear waste storage shortage.

Argonne’s new approach to recycling spent fuel from commercial nuclear reactors could help solve an expected international shortage of repository space for disposing of nuclear wastes.

In a single step, commercial fuel, which is a ceramic, can be converted to a metallic form for processing with Argonne’s pyroprocessing technology. This technology can greatly reduce the amount of waste that needs disposal in a repository.

"There’s a strong international consensus that nuclear energy will play an increasing role around the world in meeting the energy needs of growing economies, while minimizing the use of technologies that emit greenhouse gases," said John Sackett, Argonne’s associate laboratory director for engineering research. "Recent studies indicate that the main constraint on expanding nuclear power over the next 50 years will be a shortage of repositories to hold nuclear waste."

To address the problem, the U.S. Department of Energy’s Advanced Fuel Cycle Initiative (AFCI) will develop fuel recycling technologies to reduce the amount and toxicity of reactor waste.

"The world will still need repositories," Sackett said, "but we can reduce the amount of waste that has to go in them, and we can manage the waste so it decays to safe levels in hundreds of years instead of hundreds of thousands."

Argonne and other DOE laboratories have proposed an Advanced Recycle Facility (ARF) as a key component of the AFCI. The facility will:

• Process spent fuel from today’s commercial nuclear plants,
• Recast fissile materials into fuel suitable for irradiation in yet-to-be-developed Generation IV reactors (see Argonne, INEEL lead U.S. role in planning the next generation of nuclear reactors), and
• Package high-level nuclear waste for safe placement in a repository.

The ARF would remove uranium and plutonium from spent fuel along with the long-lived reactor wastes, such as americium and neptunium, which take thousands of years to decay, and recycle them into new fuel.

Burning the recycled fuel to make electricity destroys the long-lived wastes. With that gone, only the short-lived wastes will need to be stored in a repository. "The total amount of waste in the repository is reduced," Sackett said, "and in less than 1,000 years, the short-lived wastes decay until they are safer than the natural ore the original fuel came from."

Revolutionary new process
One technology expected to get close consideration for the facility is a revolutionary new process developed at Argonne to ease the burden of safely and economically disposing of thousands of tons of spent nuclear fuel now in temporary storage at commercial nuclear power plants across the United States.

In one step, the technology converts spent commercial fuel, which is a ceramic oxide, into metal. Then it can be treated with Argonne’s pyroprocessing technology to recover the uranium and plutonium for recycling into new fuel.

Pyroprocessing reduces the waste’s toxicity by removing the long-lived radioactive elements. This technology could also cut the cost and technical burden of building, licensing and maintaining a repository to isolate the remaining waste from the environment.

According to the U.S. Department of Energy, civilian nuclear reactors have produced more than 40,000 metric tons of spent fuel, about enough to cover one football field four yards deep. By 2010, DOE expects this figure to exceed 60,000 metric tons.

Argonne’s new process for converting oxide fuel to its metallic form offers a number of advantages over earlier processes, which also were developed at Argonne.

"The new electrochemical process is less complex than the earlier conversion processes," said Argonne scientist Mark A. Williamson. "It has the potential for high throughput, and its product is of higher quality with more metal and less oxide contamination, which makes it more compatible with our pyroprocessing technology."

"We’ve shown that the basic, one-step conversion works reliably on a small scale in the laboratory, where we’ve achieved complete conversion of uranium dioxide to uranium metal," he said. "Now we’re concentrating on learning more about the fundamental details of the process so we can design and test larger-scale systems."

"Over the next three years," Williamson said, "we plan to scale up to batch sizes in the tens-of-kilograms range, followed by a small-scale demonstration of the technology at Argonne-West. A logical next step would be to build a pilot plant and test it on a near-commercial scale."

For more information, please contact David Baurac.

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