Future Nuclear Reactors Could Rely on Graphite

IDAHO FALLS, Idaho—Researchers at the Idaho National Laboratory say graphite could play a key role in developing the next generation of nuclear reactors.

In the quest to develop new reactor technology, scientists say few problems are as vexing as the lack of materials that can withstand intense heat the reactors would produce. Temperatures inside such reactors would reach as high as 1,000 degrees Celsius, three times hotter than today's commercial nuclear reactors. That's hot enough to compromise present-day core materials in a matter of days.

But scientists at INL say the answer could lie on the tip of their pencils: Graphite is extremely resistant to heat and has some of the other properties the researchers are looking for.

Will Windes, a lead researcher on the project, and his team are working with grades of graphite that can absorb heat up to 3,000 degrees Celsius without any consequences whatsoever, the Post Register reports.

Graphite is also a good conductor of heat, making it a prime candidate for components used in heating nuclear fuel and in the cool-down process.

INL technology development director David Petti says other materials have been examined, but none so far offers the same advantage as graphite.

The use of graphite in nuclear reactors is nothing new.

Windes said Great Britain has been using reactors with designs similar to what his team is proposing since the 1950s. The United States researched graphite for nuclear purposes for decades, but with oil prices and enthusiasm for nuclear power plunging, the program was shut down in the 1980s, Windes said.

Windes' team in Idaho Falls is now dusting off that old research.

"We're trying to improve upon those old designs," he said. "In some ways, we're just reinventing a wheel that's already been invented, which is the price you pay for dropping something."

But Windes' team is working with some significant advantages. Scientists today have the benefit of perspective when they revisit old experiments, as well as better instruments and access to much more advanced grades of graphite, he said.

Graphite isn't a perfect solution to all nuclear problems. Over time, exposure to radiation causes it to shrink, distort and ultimately crack, Windes said. The INL team is conducting experiments largely focused on how to solve this problem.

The team placed a graphite sample in INL's Advanced Test Reactor in September, where it is exposed to similar conditions as a next-generation nuclear reactor, Windes said. The sample is scheduled to be removed in May 2011 and tested for thermal, physical and mechanical changes.

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Information from: Post Register, http://www.postregister.com

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