News » Cover Stories

Back to the future with thorium

Former Times editor's book on thorium power, the new/old 'green' nuke.



With the meltdown at the Fukushima Nuclear Power plant less than a year old and Japan sure to be feeling the effects of the radiation released in the accident for years or even decades to come, convincing somebody of the necessity and safety of nuclear power is a pretty hard sell right now. But what if you learned that there was a way to make a safer nuclear reactor, with virtually no risk of catastrophic meltdown — a reactor that could produce electricity so economically that energy might even be too cheap to meter? As an added bonus, what if that reactor could produce only a fraction of the radioactive waste that's currently a bi-product of even the most efficient modern nuclear power plant, and that waste could shed its deadly radioactivity in hundreds of years instead of hundreds of thousands?

In his new book, "Super Fuel: Thorium, the Green Energy Source for the Future," author Richard Martin reveals that not only does a technology to accomplish all those futuristic, pie-in-the-sky ideas exist, we've known about it for decades. The story of why your home isn't powered by that technology right now is a tale of Cold War necessity, political jockeying, and a future where a complacent U.S. could be playing technological catch-up — or even be beholden — to countries like China and India.

The element that could power that new, greener nuclear plant is a dull, slightly radioactive metal called thorium. One of a family of very dense elements called actinides, it shares the basement row of the periodic table with more well-known radioactive kin like uranium and plutonium.

Richard Martin, a former editor of the Arkansas Times who is now a contributing editor at Wired Magazine, began thinking about thorium after running across a blog post online by the son of a former colleague of Alvin Weinberg, an early proponent of thorium power who had been the director of the Oak Ridge National Laboratory in Tennessee from 1955 to 1973. Martin eventually wrote a story for Wired about the promise of thorium in December 2009. When he expanded that piece into a manuscript, Martin said Weinberg emerged as "kind of the hero of the book." A prophet of the risks of nuclear energy — who famously called nuclear power a "Faustian bargain" between near-limitless electricity and the long-term public vigilance needed to avoid a nuclear disaster — Weinberg was one of the first to begin seriously exploring the use of thorium as a safer source of fuel for nuclear reactors.

The reasons why thorium might be a better choice are fairly easy to understand, even for someone without a PhD. For one thing, the U.S. has at least 175,000 tons of the stuff, enough to power the country for a thousand years. For another, Weinberg and his colleagues at Oak Ridge realized that when thorium is dissolved in a molten fluoride salt solution and poured into tubes, it creates a self-regulating reactor core (called a Liquid Fluoride Thorium Reactor, or LFTR), with virtually no chance of melting down. Unlike a solid-fuel uranium reactor, if an LFTR overheats due to a lack of coolant, the liquid fluoride/thorium solution simply expands and boils out of the tubes, releasing the pressure, slowing down the nuclear chain reaction and cooling things down automatically — a process Martin likens to doubling the area of a pool table full of zinging billiard balls. More area means fewer atomic collisions, which means less heat.

As an added bonus, LFTRs could be up to 50 percent more efficient than current reactors, and would produce a tiny amount of waste compared to the amount produced by a uranium reactor. The waste produced by a thorium reactor (while radioactively "hotter," and thus more dangerous) decays in only a few hundred years.

Even with all that going for thorium and Weinberg's constant cheerleading, uranium eventually won out as America's nuclear fuel of choice, largely due to one very deadly factor: uranium-powered reactors produce the plutonium needed for nuclear bombs. At a time when the U.S. was scrambling to build nukes to keep up with the Soviets, a nationwide grid of constantly-bubbling plutonium stills was considered a fair trade-off even when weighed against some of the nastier side effects of solid-fuel uranium reactors, including the potential for meltdown and tons of deadly waste that would have to be stored for so long there might not even be any human beings left by the time it's safe to touch.

Weinberg's constant harping on the need for nuclear safety and the promise of thorium-based nuclear power eventually bugged the Atomic Energy Commission and the Pentagon enough that he was replaced by the Nixon administration as head of Oak Ridge in 1973. Martin said that while some of his papers are archived at the University of Tennessee, he found most of them inexplicably stored in a closet at the Children's Museum in Oak Ridge, Tenn.

Since Martin wrote his story for Wired in 2009, the interest in thorium as a technology has picked up — but not within the nuclear power industry in the U.S. "What was once this kind of rag-tag movement of outsiders and guys who were mostly technicians or scientists has really become a worldwide, more business-oriented, more technology-oriented phenomenon," Martin said. "China is building these reactors. India has a program to shift their entire nuclear fleet over to thorium in the next 20 years." China, Martin said, is actively stockpiling thorium, and announced last February that it will build its first full-scale LFTR plant. Meanwhile in this country, Martin said that the interviews he had with the powers that be in the U.S. nuclear industry find a "malign neglect" when it comes to the topic of changing the status quo.

"They're like: 'Why would we change? If it ain't broke, why fix it?' " Martin said. "But the fact is, it IS broke. We need to transition away from burning coal and other forms of carbon emitting energy, and the only way to do it is with natural gas and nuclear power."

The energy race for thorium power, Martin said, is already underway, and the U.S. risks being left behind, a situation that could leave us at the mercy of countries like China someday ("I tell people: 'If you like being dependent on Saudi Arabia for oil, you'll love being dependent on China for nuclear power technology,' " he said).

"A hundred years from now, when we're all dead," Martin said, "there is going to be a vibrant, renewable power industry that's going to supply a significant percentage of our power. The question is: how are we going to get from here to there? Starting to build thorium reactors now will help us bridge that divide."

Comments (4)

Showing 1-4 of 4

Add a comment

Add a comment