The Truth About Thorium and Nuclear Power
Thorium has nearly 200 times the energy content of uranium without creating plutonium—an ingredient for nuclear weapons. Is this the nuclear fuel of the future?
By Elizabeth Svoboda
Talk of a large-scale U.S. nuclear renaissance in the post-Three Mile Island era has long been stalled by the high cost of new nuclear power plants, the challenges of safeguarding weapons-grade nuclear material, and the radioactive lifespan of much nuclear waste, which can extend far beyond 10,000 years. But a growing contingent of scientists believe an alternative nuclear reactor fuel—the radioactive metal called thorium—could help address these problems, paving the way for cheaper, safer nuclear power generation.
Three to four times more plentiful than uranium, today's most common nuclear fuel, thorium packs a serious energetic punch: A single ton of it can generate as much energy as 200 tons of uranium, according to Nobel Prize-winning physicist Carlo Rubbia. In the mid-twentieth century, some U.S. physicists considered building the nuclear power landscape around thorium. But uranium-fueled reactors produced plutonium as a byproduct, a necessary ingredient for nuclear weapons production, and uranium ended up dominating through the Cold War and beyond.
Thorium could recapture the lead if a Virginia-based company called Lightbridge (formerly Thorium Power) fulfills its promise. Lightbridge was founded on the vision that the existing fleet of nuclear reactors would continue to function for decades to come, so its proprietary nuclear fuel assembly—which features a small amount of uranium surrounded by a blanket of thorium—is designed to work in light water reactors, the most common variety in service worldwide. The company is also developing an all-metal fuel capable of incorporating thorium. "This is like going from leaded to unleaded fuel for your car—the operation [of the reactors] is the same," says Seth Grae, Lightbridge's CEO.
Examining the reactions inside a thorium-fueled reactor, however, reveals some important differences. In a traditional light water reactor, uranium-235 interacts with uranium-238 to produce plutonium-239 as a byproduct—a radioactive isotope that can be used for weapons. But when thorium is used instead of uranium-238 as a fertile material to kickstart nuclear fission, the thorium eventually "becomes uranium-233, which fissions almost instantaneously in the reactor, generating other isotopes that make power," Grae says. That means usable weapons-grade nuclear material is not produced, which would theoretically eliminate some security issues now associated with nuclear plants. Grae also claims thorium-powered light water reactors produce a much smaller volume of waste products that decay to relatively safe levels in just six to seven hundred years. Lightbridge has completed test runs of its thorium-based fuels in Russia and hopes to conduct tests at Idaho National Labs next year, meaning its thorium-fueled reactors could be up and running here in the U.S. as early as 2015.
Even as Lightbridge hurtles toward commercialization, other researchers are hatching longer-range plans to squeeze even more efficiency out of thorium. "Thorium is a great fuel in light water reactors, but it really excels in molten salt reactors," says David LeBlanc, a nuclear physicist at Carleton University in Ottawa, Canada. The fuel rods used in light water reactors tend to succumb to radiation damage within a few years. In proposed molten salt reactors, by contrast, thorium is dissolved in a mixture of damage-resistant liquid salts, allowing for more plant uptime. Radioactive fission products generated in a thorium-fueled molten salt reactor can also be re-added to the reactor for many successive rounds of power generation, enabling utilities to extract more power from small amounts of fuel. Japanese company IThEMS, which is working on a thorium-fueled molten salt reactor, estimates power generated by such a reactor would cost at least 30 percent less than power from today's light water reactors. In addition, molten salt reactors could potentially burn through hazardous waste stockpiles produced by previous generations of nuclear reactors.
Still, LeBlanc says new test reactors need to be built so that scientists can confirm the practicality of the thorium-molten salt approach (some observers think the corrosion salt inflicts on reactor surfaces could cause problems), so it may not take off commercially for more than a decade. In the meantime, Grae relishes the prospect of being the first to capitalize on thorium's efficiency and waste-management advantages. "We've already gotten results in the reactor in Russia, so what we're doing is very different from a ‘paper reactor,'" he says. "We're very confident that this will prove out."
An answer to the troubled nuclear industry?
I've added some thoughts and comments to the thread already, but I wanted to share some more. I also wanted to post a copy of the letter I sent to Senator Harry Reid. In 2008, he co-sponsored a bill with Senator Orrin Hatch regarding thorium energy. Because the Senators from my state are fiercely conservative and because Senator Reid co-sponsored this bill, I decided to contact him instead of my own Senators. I mentioned several other forms of energy as well. In the last paragraph, I went off topic and mentioned something regarding gay rights.
Dear Senator Reid:
I know I'm not from your state, but it just so happens that, as a liberal, I don't think either Senator from my state fully represent me. That is why I felt the need to contact someone else in the first place. In addition, this is regarding an issue of a bill that you co-sponsored with Senator Orrin Hatch of Utah.
A few years ago you and Senator Hatch sponsored a bill regarding the use of Thorium as a source of energy. I am all for alternative energy. One thing I love about Texas is that it is the state that is the largest producer of wind energy in the nation. However, wind is not enough. Thorium, as you already know, is an abundant and efficient source of energy. Please don't forget about thorium. We cannot ignore the energy needs of this nation. We are one of the largest nations in the world and the largest consumers of energy, at least I think we still are as China will surpass us if it has not already.
Don't forget, however, that even thorium has its limits. Ultimately, we need more research in hydrogen. Water can be used as a hydrogen fuel source, but there needs to be a more efficient way.
Another hydrogen-based energy source is the largest source of energy in the entire solar system. More efficient collection of solar energy is very important. This source of energy has been available for around 4.5 billion years, and we sadly make little use of its energy potential.
The sun is fusion energy. We also need to develop a way to create fusion on a smaller scale but with efficiency. Imagine a whole city powered by a miniature star or even better, through cold fusion. It's even more efficient than any of the forms I've mentioned above.
Anti-matter may be extremely unstable, but when it comes into contact with matter, the energy produced is unfathomable for many. Such a reaction is rare, but with some time and patience, finding a much more efficient way to collect and use anti-matter will allow us to not only have a wonderful energy source that can take care of our energy needs and allow us to travel to other galaxies. Right now, an ounce of anti-matter costs more than the GDP of the United States. This is unacceptable. We must research anti-matter further and learn to produce it efficiently.
Finally, I would like to mention algae. Algae is the most important organism on the planet, yes even more important than humans. It is the largest source of oxygen in the world both in the air we breathe and in the salty and fresh bodies of water in the world. Without algae, we could not survive. Algae also has the potential for being biofuel. In producing this form of energy, we can also increase oxygen levels. By reducing the overall number of plants in the world, including trees, we have reduced the sources of oxygen on this planet. With algae, we can start help reduce or eliminate this trend while creating a fuel source for our automobiles! It's a win/win for us.
We already have some biofuels, but where are they? Why can't I go to most local gas stations and find ethanol pumps along with gasoline and diesel? Some cars, trucks, SUVs, etc. can use both, so why don't we find both everywhere? This also needs to change.
I am sure you've heard of all this energy sources already, but I wanted to express my belief that more needs to be done to reduce and eventually do away with the use harmful and inefficient forms of energy like coal and gasoline.
This last part has no relation to energy. I have never looked up your stance on this issue, but it almost has to be closer to my own when compared to the beliefs of my own Senators. As a gay man, I see so much discrimination, and it makes me mad. I should be free to marry the person I love and to adopt children without any hassle. I know people often hate what they do not understand, but if people are taught more about homosexuality, hearts and minds will change. I hope you will support efforts to make these dreams become reality.
<I am withholding my real name in this copy>