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Thorium as a green nuclear solution
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Robert Hargraves discusses the advantages of thorium, particularly the liquid fluoride thorium reactor, as a clean and safe nuclear solution that could compete with coal for inexpensive energy generation. Suggests a 10-year plan for bringing this forward.
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 Robert Hargraves, pictured here at a recent lecture (see video below) he gave for Google Tech Talks, has taken a fancy to the subject of liquid fluoride thorium reactors, becoming a proponent for the technology that would be too expensive for regular corporate interests to develop, but which could become cheaper than coal, once developed, and much cleaner and safer than uranium-based nuclear power. Bob received a graduate degree in physics, Dartmouth, then spent his career in IT industry. He served as CIO at Boston Scientific, doing medical devices, retiring in 2000. More recently, he has been teaching a continuing education course at Dartmouth on Energy Policy and Environmental Choices, Rethinking Nuclear Power. | ||||
Last Monday, I interviewed Robert Hargraves about thorium as a more clean, safe, and affordable alternative to uranium-based nuclear reactors. Though there have already been some plants built over the past decades using Thorium, the technology is still under-developed and under-utilized, according to proponents like Hargraves.
Safety
The safety of Thorium over Uranium-based reactors come from several factors. Liquid fluoride thorium reactors eliminate the possibility of a run-away nuclear reaction. The fuel fluid expands as heated, diluting the fissile material in the critical reactivity zone. If there is ever a problem, the reacting fluid can simply be drained out of the reaction chamber into a pan below the chamber, where it will not react. The decay properties or radiation of the waste product are not as bad with Thorium reactors as they are with uranium-based reactors. Also, the by-products and process involved in making the fissile fuel for Thorium reactors is not so readily weapons-grade-capable as the Uranium-based reactor process. While Uranium-based power was a spin-off of nuclear weapon development, Thorium tends to go in the other direction -- moving nuclear power away from simultaneous nuclear weapons support.
History
Hargraves pointed out several Thorium-based nuclear plants already built, including a 300 MW pebble bed reactor that ran for a decade in Germany. The U.S. Air Force had a program back in 1965 that lasted for around four years, in which they were looking at Thorium to power a nuclear air craft that could stay airborne indefinitely. The advent of missiles and satellite technology made that need subside enough to scrap the program.
Advantages
One of the primary advantages of the Liquid Thorium Reactor, according to Hargraves, is that it is scalable. He envisions 100 megawatt power stations being made for the same cost as an airplane, shipped to a site to generate electricity for under 3 cents per kilowatt-hour -- less than coal power in most places.
Another advantage Hargraves points out is that Thorium reactors operate at higher temperatures, making the energy conversion more efficient, so that less energy is thrown away as waste heat. The higher the heat, the more efficiency because you can get higher pressures of the steam which runs the turbines. Lower heat and thus lower pressures means less efficiency, hence more waste per kw-h produced.
The availability of Thorium is another advantage. Hargraves said there is three times as much Thorium available as Uranium -- enough to last hundreds of years. Furthermore, there are stockpiles of it just sitting around from the Manhattan project days when they didn't know what to do with it.
Mini Manhattan Project
Speaking of Manhattan Project, Hargraves says it would take a major initiative approaching that kind of support for Thorium to get it off to a reasonable start. He proposes a "ten year plan" comprised of two five-year plans. In the first five years, the governments of several nations would work together to bring the technology to prototype stage, at a cost of approximately $1 billion dollars. Then, in the second five years, major corporate players like Westinghouse would take the prototype commercial to the point that one Thorium power plant could be made each week.
The sticker price for the development phase of this technology is beyond the budget for even large businesses, so Hargraves recommends that national labs do the development.
As I heard him describe this, I had a hard time getting excited about Thorium as a viable cleaner alternative to the present mainstream energy sources. I'd rather keep my hope out for something like magnet motors, electromagnetic overunity, cold fusion or other exotic energy modalities to pull through, which could be small, portable, baseload capable 24/7, and inexpensive once developed at far less cost and time.
Aim High
The following presentation was mentioned in the interview, which Hargraves gave at Google Tech Talks on May 26, 2009.
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Hargrave Interview Audio
Contact
- Bob can be reached by email via robert.hargraves@gmail.com
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