By Walter Sorochan Emeritus Professor San Diego State University Posted April 20, 2012; Updated November 13, 2021. Disclaimer The information displayed herein is intended to simplify the complexity of the nuclear power plants. The nuclear power plant disasters at Three Mile Island, Chernobyl and Fukushima have made all of us aware of the dangers inherent in using uranium to generate electricity. Overlooked in the heat of these catastrophes has been thorium, a safer alternative to uranium. The mass media has given no attention to thorium. But this may be changing as countries the world over are attempting to harness thorium as a safer substitute energy for uranium. Countries like India and China, where air pollution has become a crisis death, are endeavoring to implement thorium power plants to generate clearner electricity. Purpose of article: Awareness that there is a safer alternative fuel to current nuclear power plants. Kirk Sorensen discuses in U-tube: Thorium as an alternative power supply to nuclear radiation: 10 mns long Switching from uranium to thorium as our primarily energy fuel could lead to cheaper, safer and more sustainable nuclear power. If you haven't heard of thorium or this idea, you are not alone! This article looks into this well kept secret. So .... what is thorium? Thorium: "is a natural radioactive chemical element with the symbol Th and atomic number 90. It was discovered in 1828 and named after Thor, the Norse god of thunder. In nature, virtually all thorium is found as thorium-232, and it decays by emitting an alpha particle, and has a half-life of about 14.05 billion years (other, trace-level isotopes of thorium are short-lived intermediates of decay chains). It is estimated to be about four times more abundant than uranium in the Earth's crust and is a by-product of the extraction of rare earths from monazite sands. Thorium was formerly used commonly as the light source in gas mantles and as an alloying material, but these applications have declined due to concerns about its radioactivity." Wiki: Thorium Monazite, the most common and commercially most important thorium-bearing mineral, is widely distributed in nature. Monazite is chiefly obtained as a sand, which is separated from other sands by physical or mechanical means. Robert Hargraves and Ralph Moir explore the early days of decisions about selecting a nuclear power plant technology --- uranium vs thorium. Enrico Fermi argued that the uranium-plutonium breeder made more weapons faster in the Manhattan Project. Atomic physicist Edward Teller promoted the LFTR to the last month of his life. Thorium LFTR: LFTR = Liquid Fluoride Reactor Reduce Advantage of thorium vs. uranium & coal:
Dr. Robert Hargraves, Why thorium is cheaper, safer than coal; Length= 39:14 mns. Differences between thorium and uranium: Thorium is much different than uranium when used as a nuclear fuel. It is not fissile; meaning it cannot go critical and generate a nuclear chain reaction. This is referred to as thorium's safety valve by Sorensen. It must undergo neutron bombardment to produce a radionuclide that can sustain a nuclear reaction. A thorium-fueled reactor must be jump-started with a fissile isotope such as uranium (U235) and/or plutonium (Pu239; Pu241). Neutron bombardment of thorium results in this reaction: Th232 + Neutron = U233. Uranium233 is a man-made fissile isotope with a half-life of 160,000 years, and is well-suited for use in nuclear reactors. After Th232 is converted, U233 can be unloaded and then fed to the core of another reactor to be used as fuel in a closed cycle. Alternatively, U233 can be bred from thorium in an outer blanket surrounding a plutonium and/or uranium core, the U233 separated, and then fed back into the core. These are called "breeder reactors" because thorium is the fertile fuel that breeds a fissile radionuclide. Radioactive materials are recycled so there is little waste left behind. There are other significant advantages to the use of thorium in nuclear reactors. The raw material, thorium, is much more abundant than uranium and emits only low-level alpha particles. It has one isotope and therefore, does not require an enrichment cycle to be used as fuel. It is many times more energy efficient than uranium. A thorium reactor produces no plutonium that can be made into atomic weapons and less longer-lived radionuclides than a uranium-based reactor. Because there is no chain reaction, there is no chance of a meltdown. Fissile means it cannot go "critical" and generate a nuclear chain reaction. Nuclear waste from past operations that contain fissile uranium and plutonium can be used as start-up fuel. Conclusions about thorium as a substitue for uranium:
This LFTR reactor engine is made up of the following components:
Molten Salt Reactor: In 1952, in response to a radical scheme to develop a reactor-powered aircraft, a revolutionary reactor was built using a liquid fuel. This led to the Molten Salt Reactor(MSR), which was designed, built and operated for five years. Capable of burning any nuclear fuel, the MSR forms the fissile, energy producing part of the LFTR (shown here in orange). Thorium conversion: To convert the Thorium into a reactor fuel, it must be exposed to a neutron source. After absorbing a neutron from the reactor core, the Thorium is removed to a decay tank where it converts to Uranium 233, the primary fuel for the reactor. Due to the withdrawal of funding, the thorium blanket (shown in green) was never added to the MSR. What if there is a melt down? You can't have a meltdown in a molten salt reactor, the core is already molten. In a standard reactor, a meltdown is a potential disaster. In a fluid fueled reactor, its normal operating procedure. What if there's a leak? All the salts are solid at room temperature. If any salt leaks out, it will solidify. What if there is an explosion? There is no internal pressure in the LFTR. In fact, there is a slight negative pressure. If anything were to break open the reactor, the salts would simply solidify. What if the reactor overheats? If the fuel salt overheats, the salt expands, which makes the reaction slow down and eventually stop. If the temperature of the salt rises too high, a solid plug of salt in a drain pipe would melt and the fuel would drain to a dump tank where a nuclear reaction is not possible. This 'freeze plug' can also be used to simply switch the reactor off. What about proliferation of nuclear weapons? A LFTR is a very poor option for making nuclear weapons. No weapon has ever been made from U233, the LFTR's main fuel. In fact, it could burn up old weapons along with waste from solid fuel reactors. "Advantages of thorium/uranium fuel cycle compared to the uranium/plutonium cycle have mobilized a community of scientists and engineers who have resurrected the research of the Alvin Weinberg era and are attempting to get thorium based power into the mainstream of research, policy and ultimately, production.
Nuclear engineers can extract 100% of thorium’s usable energy, compared to just 0.7% for uranium. So, as this illustration demonstrates, it takes much more raw material and leaves much more dangerous waste to generate 1,000 MW of electricity in a year using uranium than it does using thorium. Article by Sorensen: thorium machine design is no longer active. Thorium Schedule & Benefits --- A Thorium LFTR could be working in 5 years… Thorium activity in world: There is a lot of international interest in building a thorium power plant that would replace the uranium one.
There are significant forces which stand to loose big if LFTR [ thorium reactor ] becomes a commercial reality. GE makes significant money on nuclear fuel rod manufacture and handling. The coal lobby is huge in this country and hauling coal is one of the most lucrative jobs for the railroads. Factor in big oil too. Fossil fuel corporations aren't worried about fusion becoming reality any time soon hence plenty government funding for that big corps. LFTR, on the other hand, is a real competitor! Safety of nuclear power plants "There are more than 400 nuclear reactors operating in the world. A nuclear power station has 35-40 years of operating life. After that it must be dismantled and the area must be cleaned up [ the decommissioning process ]. Clean-up means getting rid of used up uranium rods and other radioactive materials! But so far, only a few nuclear power stations have been completely decommissioned in the world. Germany has stopped building nuclear power plants, while California has stopped using San Onufre power plant on the west coast. It has been estimated that decommissioning could last about 50 years and it would cost more than the construction cost." MacPherson: decommissioning nuclear reactors 2011 The other big "no speak" issue is storing nuclear wastes from current operating nuclear power plants. Uranium wastes have a very long half-life; like 160,000 years. At this time, most nuclear plants store waste materials on site. When there is a nuclear disaster, as occurred in Three Mile Island, Chernobyl and Fukushima, the highly radio-active and toxic waste materials are at extreme risk of being released into the environment and poison-radiate people. The world has not found a safe place, nor a way to store toxic radioactive materials. Inability to solve this catrostrophic problem makes use of uranium in today's nuclear power plants a colossal mistake! Al Gore has commented on the historical record and reliability of nuclear power in the United States:
Amory Lovins, USA physicist, commented on the historical record of nuclear power in the United States: "Of all 132 U.S. nuclear plants built (52% of the 253 originally ordered), 21% were permanently and prematurely closed due to reliability or cost problems, while another 27% have completely failed for at least a year or more. The surviving U.S. nuclear plants produce ~90% of their full-time full-load potential, but even they are not fully dependable. Even reliably operating nuclear plants must shut down, on average, for 39 days every 17 months for refueling and maintenance, and unexpected failures do occur too." Wiki: Nuclear power USA 2011 Summary: "The safety and efficiency of nuclear power is hotly disputed; and both advocates and opponents have at times tended to overstate their case. What cannot be disputed is that all forms of power generation are inherently dangerous [ especially coal ]; all technologies are particularly accident prone and carry huge financial risks during the pioneer stage of their development." Chater: history nuclear power Ever wonder why insurance carriers refuse to insure nuclear [ uranium ] power stations? Instead the national governments are taking the risks! Nuclear power plants are not as reliable or safe as they are espoused by power companies. The use of uranium to generate electric energy has major hazardous flaws. The numerous nuclear power plant disasters, and especially the latest Fukushima disaster, support this observation. Inability to get rid of nuclear radiation emitting wastes in a safe manner is a colossal and ignored issue! MacPherson: decommissioning nuclear reactors 2011 Continuing concern about the lurking danger of existing use of uranium power plants has encouraged scientists to consider thorium as alternative source of electric energy power. Reference: Beissmann Tim, "The thorium-powered car: Eight grams, one million miles," Car Advice, August 16, 2011. Beissmann: thorium driven car 2011 Chater James, "A history of nuclear power," Focus on Nuclear Power Generation, 2005. Chater: history nuclear power Clark Duncan, "Thorium nuclear power," The Manchester Guardian. July 12, 2009. Clark: Thorium nuclear power Fan-Chiang Liona, "Fusion Basic Economics," 21st CENTURY SCIENCE & TECHNOLOGY, August 2014. Fan-Chiang: Fusion economics 2014 Fissile: Unlike natural uranium, natural thorium contains only trace amounts of fissile material (such as 231 Th), which are insufficient to initiate a nuclear chain reaction. Fissile means it cannot go "critical" and generate a nuclear chain reaction. Thorium fuel cycle Ghunawat Virendrasingh, "Design of world's first Thorium based nuclear reactor is ready," IndiaToday, Mumbai, February 14, 2014. Ghunawat: world's first thorium plant Hargraves Robert and Ralph Moir, "Liquid Fluoride Thorium Reactors - An old idea in nuclear power gets reexamined," American Scientist Reprint, July-August, 2010. Article by Hargraves: Thorium reactors pdf is no longer active. India developing thorium reactor: "Thorium: Green Friendly Nuclear Power." March 06, 2011. Original article taken off the internet.
LeBlanca David, "Molten salt reactors: A new beginning for an old idea," Elsevier Nuclear Engineering and Design 240 (2010) 1644–1656 Article by LeBlanca: Molten salt reactors is no longer active. List of thorium-fueled reactors [ From IAEA TECDOC-1450 "Thorium Fuel Cycle - Potential Benefits and Challenges", Table 1: Thorium utilization in different experimental and power reactors. ] Wiki: Thorium fuel cycle
MacPherson Christina, "The eternal cost of dealing with dead, but radioactive, nuclear reactors," Nuclear News, September 15, 2011. MacPherson: decommissioning nuclear reactors 2011 "There are more than 400 nuclear reactors operating in various countries. A nuclear power station has 35-40 years of operating life. After that it must be dismantled and the area must be cleaned up (the decommissioning process). But so far, no nuclear power station has been completely decommissioned in the world. It has been estimated that decommissioning could last about 50 years and it would cost more than the construction cost." Pentland William, "Is Thorium the Biggest Energy Breakthrough Since Fire? Possibly," Forbes, September 11, 2011. Pentland: Thorium energy breakthru' 2011 Sazawal Vijay, "India Slashes Plans for New Nuclear Reactors by Two-Thirds," Neutron Bits, April 6, 2018. Sazawal: India cuts back on power 2018 Sorensen Kirk, "Thinking Nuclear? Think Thorium," [ Thorium, a Readily Available and Slightly Radioactive Mineral, Could Provide the World with Safer, Clean Energy ] Machine Design, March 16, 2010. Article by Sorensen: thorium machine design is no longer active. Sorensen Kirk, "Thorium," Ted U-tube, April 22, 2011. Sorensen: thorium Ted Utube Kirk Sorensen is founder of Flibe Energy and is an advocate for nuclear energy based on thorium and liquid-fluoride fuels. For five years he has authored the blog "Energy from Thorium" and helped grow an online community of thousands who support a renewed effort to develop thorium as an energy source. He is a 1999 graduate of Georgia Tech in aerospace engineering and is also a graduate student in nuclear engineering at the University of Tennessee. He has spoken publicly on thorium at the Manchester International Forum in 2009, at NASA's Green Energy Forum in 2008, and in several TechTalks at Google. He has been featured in Wired magazine, Machine Design magazine, the Economist, the UK Guardian and Telegraph newspapers, and on Russia Today. He also taught nuclear engineering at Tennessee Technological University as a guest lecturer. He is active in nonprofit advocacy organizations such as the Thorium Energy Alliance and the International Thorium Energy Organization. He is married and has four small children. SSTAR, "Small, sealed, transportable, autonomous reactor," Wikipedia. SSTAR portable nuke reactor Thorium Energy Alliance [ John Kutsch director ], "T.E.A. Resources," TEA: thorium info 2012 Thorium engine power plant cost: Article about Thorium engine power plant cost is no longer active.
Worrall Eric, "India: We will build our own ITER Fusion Reactor," The Times of India, April 10, 2015. Worrall: India builds fusion reactor 2015 Westenhaus Brian, "One Step Closer to a Thorium Fueled Power Plant," New Energy and Fuel, May 3, 2010. Westenhaus: Norway-Sweden activity 2010 Wikipedia, "Molten Salt Reactor." Wiki: MSR Wikipedia, "Nuclear power in the United States," 2011. Wiki: Nuclear power USA 2011 Wikipedia, Thorium. Wiki: Thorium World Nuclear Association, "Outline History of Nuclear Energy," June 2010. World Nuclear Assoc: history Worthington Bryone, "Post-Fukushima world must embrace thorium, not ditch nuclear," The Manchester Guardian Uk, March 09, 2012. Worthington: thorium activity internationally 2012 The man whose inventions led to nuclear power proliferation knew thorium was preferable to uranium – it's time we caught up. |