Thorium and Molten Salt Reactors
/The latest nuclear power industry proposals focus on smaller reactors and the possibility of thorium fueled reactors. As the nuclear industry explores other fission products, Fairewinds Energy Education has been peppered with hundreds of questions regarding the feasibility and safety of thorium reactors that the nuclear industry is touting as a newer safer form of nuclear power. The Liquid Fluoride Thorium Reactor (LFTR) is being sold as a “market based environmental solution” and advertised by the nuclear industry as cheaper than coal. Molten Salt Reactors (MSR) use a molten salt mixture as the primary coolant, and sometimes the molten salt is even mixed directly with thorium in the reactor fuel.
Since Fairewinds has received so many questions regarding Thorium Reactors, let’s look at the facts about Thorium:
Liquid-Fluoride Thorium Reactor Design
According to questions we have received, proponents claim that thorium reactors produce less waste and its half-life is “only” a few hundred years rather than thousands. That still means hundreds of years of waste. However, contrary to proponent’s claims
If the spent fuel is not reprocessed, thorium-232 is very long lived (half-life: 14 billion years) and its decay products will build up over time in the spent fuel. This will make the spent fuel quite radiotoxic, in addition to all the fission products in it. It should also be noted that inhalation of a unit of radioactivity of thorium-232 or thorium-228 (which is also present as a decay product of thorium-232) produces a far higher dose, especially to certain organs, than the inhalation of uranium containing the same amount of radioactivity. For instance, the bone surface dose from breathing an amount (mass) of insoluble thorium is about 200 times that of breathing the same mass of uranium. 1
And there is still no geologic repository for the waste in the USA and most of the world, and even if there was, the encapsulation process designed to hold the waste has recently been shown to last only 100 years.
On the question of safety, here is how the Union of Concerned Scientists in its Statement on Thorium Fueled Reactors, answers:
Some people believe that liquid fluoride thorium reactors, which would use a high-temperature liquid fuel made of molten salt, would be significantly safer than current-generation reactors. However, such reactors have major flaws. There are serious safety issues associated with the retention of fission products in the fuel, and it is not clear these problems can be effectively resolved. Such reactors also present proliferation and nuclear terrorism risks because they involve the continuous separation, or “reprocessing,” of the fuel to remove fission products and to efficiently produce U-233, which is a nuclear weapon-usable material. Moreover, disposal of the used fuel has turned out to be a major challenge. Stabilization and disposal of the remains of the very small "Molten Salt Reactor Experiment" that operated at Oak Ridge National Laboratory in the 1960s has turned into the most technically challenging cleanup problem that Oak Ridge has faced, and the site has still not been cleaned up. 2
Another claim thorium proponents make is that a thorium reactor is nearer to closing the nuclear fuel cycle. In an interview discussing that topic, Arnie Gundersen said,
The French, and actually the Japanese bought into this. No one has really what we call closed the nuclear fuel cycle. The Japanese tried for years and spent trillions of yen or hundreds of billions of dollars in trying to reprocess fuel and it failed every time. My point is if we had spent that money on alternative energy sources, we would be much more likely to have a solution right at hand that is really cheap. And instead we put all our money on the wrong horse in this race.3
Following a review, even the U. S. Department of Energy has concluded placed Thorium Reactors in the same category as all other nuclear power reactors.
The choice between uranium-based fuel and thorium-based fuel is seen basically as one of preference, with no fundamental difference in addressing the nuclear power issues [of waste management, proliferation risk, safety, security, economics, and sustainability]. Since no infrastructure currently exists in the U.S. for thorium-based fuels, and the processing of thorium-based fuels is at a lower level of technical maturity when compared to processing of uranium-based fuels, costs and RD&D [research, development and deployment] requirements for using thorium are anticipated to be higher. 4
Thorium 232 is not fissile, that means it can't split and create power. Thorium 232 needs a uranium reactor to get it started by sending out neutrons that the thorium 232 can absorb. When that happens, the thorium 232 changes to U233, which is fissile. So behind every thorium reactor there still is uranium and plutonium that must be disposed of.
hargraves-fig2_1
To date, Fairewinds has seen no evidence that Thorium Reactors are ready for prime time. Thorium Reactors face the same environmental risks as the current fleet of nuclear power plants. And as Hurricane Sandy has proven, those issues will be even more challenging as global warming and its subsequent impact on weather patterns throughout the world continues to impact energy production. Nuclear power plants like Thorium Reactors need a stable geological location as well as long-term storage solutions.
As climate change becomes impossible to ignore, the nuclear industry is attempting to market itself as a cleaner alternative to fossil fuels. While nuclear reactors do not generate sooty particles that wind up in the atmosphere, the heavy dependence on cooling water for nuclear power plants makes nuclear power unfeasible as water temperatures rise around the globe. Additionally, mining and transporting uranium are carbon heavy activities. Finally, studies in Sweden have shown that the ceramic encapsulation, the anticipated solution to keep waste secure for hundreds of years will not even last 100 years, so there currently is no long term viable storage solution for nuclear waste.
In a joint project between the Nuclear Policy Research Institute and the Institute for Energy and Environmental Research (IEER), nuclear physicist Dr. Arjun Makhijani has written: Carbon-Free and Nuclear-Free: A Roadmap for U.S. Energy Policy. A former energy policy analysist for President Carter, Dr. Makhijani understands nuclear power and energy forecasting. Read the executive summary and the whole book will give you some of the energy answers you are seeking.
2) Union of Concerned Scientists Statement on Thorium Fueled Reactors
Capital Forums’ Tom Ritter interviews Arnie Gundersen
Roald Wigeland et al, "AFCI Options Study," Idaho National Laboratory, INL/EXT-10-17639, September 2009.
