With the nuclear industry in a bit of a post-Fukushima funk right now, advocates of clean energy are dusting off plans to use the lesser-known metal thorium to run power plants and vehicles as an alternative to fossil fuels.
Supporters say thorium — an element named for Thor, the Norse God of Thunder — is more abundant, produces less waste and is less dangerous than uranium, while at the same time a great source of energy that won’t add to greenhouse gas emissions.
"We are spreading the word and reacting to an amazing amount of interest," said John Durham, an entrepreneur and co-founder of the London-based Weinberg Foundation, which launched last month to promote thorium as a fuel source.
Durham points to China, which announced earlier this year that it was building a new thorium-based molten-salt reactor, a significant step in technology development. India, too, is on track to do the same.
"Thorium is a tremendous alternative to uranium fuel cycle," Durham said. "We want to pull together a forum for discussing thorium with robust and truthful conversations."
The Weinberg Foundation is pushing utilities in the United Kingdom and elsewhere to invest in thorium projects. It's serving as a sort of clearinghouse and is funded by Baroness Worthington, a member of the House of Lord and a leading European climate-change activist.
In the United States, thorium advocates are meeting next week in New York City to network, hear new research developments and strategize about how to pry loose funding from private industry. Kirk Sorensen is one of them. Sorensen is a NASA engineer who started his own firm, Flibe Energy, to develop a small thorium-powered reactor using a liquid salt core.
"We recognized this is a new and different technology and developing it is significantly different from the existing nuclear industry," Sorensen said.
The technology doesn't require using cooling water under high pressure to transfer the heat of the reaction into steam to drive a turbine. That, Sorensen explains, means the reactor core is less complex than a traditional uranium-fueled reactor.
"The most fundamental difference is that it uses a salt as a coolant," Sorensen said. "It's chemically stable and can operate at high temperature and low pressure. Water cooled reactors have to be operated at high pressure, and only make moderately high temperatures."
Another advantage is that waste produced by thorium reactors can't be used to make nuclear weapons — at least it’s an advantage if the goal is to stop nuclear proliferation across the globe. Thorium reactors are also easier to shut down, he said.
Sorensen said that his design is similar to ones that existed in the late 1960s and early 1970s when the Oak Ridge National Laboratory ran a thorium reactor. Sorensen said the biggest obstacle is unearthing technical know-how that was lost when the project was canceled in 1974.
He's been hunting down engineers who worked on the reactor and posting old technical documents on the Energy for Thorium website.
Sorensen said his firm does have interest from several investors, but he expects that even a small demonstration reactor will take several hundred million dollars to build. He's not counting on the government for help.
Lightbridge Corp., a McLean, Va.-based energy firm, is also developing a thorium reactor, but its design is more like a current uranium-based reactors. The Lightbridge thorium-based nuclear fuel uses a seed and blanket fuel assembly where the central region of the fuel assembly (seed) can be separated from the outer (blanket) region where a mixture of thorium and uranium oxide mixture sits, according to Lightbridge's website.
"The seed and blanket design offers several benefits, including more efficient utilization of the thorium component and decreased used fuel inventory," the company said.
Despite a growing buzz about thorium technology, not everyone is convinced of a thorium-fueled future.
"There are a small boatload of fanatics on thorium that don't see downsides," said Dan Ingersoll, senior project manager for nuclear technology at the Oak Ridge National Laboratory.
"I'm looking for something compelling enough to trash billions of dollars of infrastructure that we have already and I don't see that."
Ingersoll said that the waste produced by thorium reactors is easier to track, making it more difficult for terrorists or others to reprocess it. He cautioned, however, that it is still a radioactive material.
"It doesn't eliminate the (nuclear waste) product, it's just not as bad," Ingersoll said.
Ingersoll admits that thorium-powered reactors make sense for countries such as India, which doesn't have access to uranium supplies as does the United States.
"A thorium-based fuel cycle has some advantages, but it’s not compelling for infrastructure and investments," Ingersoll said.
That outlook isn't shared by inventors such as Charles Stevens, who heads up the Massachusetts-based Laser Power Systems. Stevens believes he can build a thorium-powered laser, as well as a small thorium-powered car, something Cadillac considered back in 2009.
Stevens says he's talked to French authorities and kit car makers about entering a thorium powered car in the LeMans auto race. Now that would be a race I'd pay to watch.