Update: See our full page on Molten Salt Reactors for more info. More neutrons are released per neutron Thorium has 6 naturally occurring isotopes. challenging route, one could obtain weapons material. Yes. Reprocessing spent fuel requires chopping up radioactive fuel rods by remote control, then dissolving them in concentrated nitric acid from which plutonium is precipitated out by complex chemical means. Posted on November 3, 2019 by beyondnuclearinternational. Although thorium advocates say that thorium reactors produce little radioactive waste, they simply produce a spectrum of waste thatâs different from those from uranium 235, which includes many dangerous alpha and beta emitters and isotopes with extremely long half-lives, including technetium 99, with a half-life of 300,000 years, and iodine 129, with a half-life of 15.7 million years. However, uranium-238 is long-lived (its half-life, the time it takes for half of it to undergo radioactive decay, is nearly 4.5 billion years) and thorium-234, the isotope that results from the decay of uranium-238, is more radioactive. The MSRE successfully proved that the concept has merit and can be operated plutonium is that it can be chemically separated from the waste and perhaps used in bombs. One especially cool possibility suitable for the thermal-breeding capability of the Th-U fuel cycle Hype alert  If someone on the internet told you something unbelievable about Thorium, you might want to check out our Thorium Myths page just to double check it. Up and coming nuclear reactor powerhouses China and India both have substantial reserves of This still includes many dangerous alpha and beta emitters, and isotopes with extremely long half-lives, including iodine-129 (half-life of 15.7 million years). reprocessed, reactors could be fueled without mining any additional Liquid Fluoride Thorium Reactors (LFTR). Current uranium waste is 30,000 tons per year. This means that the contaminants could be chemically separated and the material Molten-salt reactors are particularly well-suited for the thorium fuel cycle. year time scale. Thorium is very insoluble, which is why it is plentiful in sands but not in seawater, in contrast to uranium. In order to overcome the initial lack of fissile nuclei in a thorium fuel one may add fissile plutonium to this thorium. Thorium is a naturally-occurring, slightly radioactive metal discovered in 1828 by the Swedish chemist Jons Jakob Berzelius, who named it after Thor, the Norse god of thunder. And very importantly, thorium is not fissile. After absorbing a neutron, thorium-232 is transmuted into thorium-233, which then beta-decays with a half-life of 22 minutes into protactinium-233, which is chemically distinct from the parent thorium. Instead of thorium, a Molten Salt Reactor can use uranium-235 or plutonium waste, from LWR and other reactors. Nuclear reactor fuel contains ceramic pellets of uranium-235 inside of metal rods. This means that if the fuel is to shut down for fuel management, etc.). The uranium 233 produced in thorium reactors is contaminated with uranium 232, which is produced through several different neutron absorption pathways. ⢠In the conversion chain of 232Th to 233U, 233Pa is formed as an intermediate, which has a relatively longer half-life (~27 days) as compared to 239Np (2.35 days) in the uranium fuel cycle thereby requiring longer cooling time of at least one year for completing the decay of 233Pa to 233U. Thorium reactors are amongst those being suggested at this time. Thorium reactors have long been proposed as a cleaner, safer alternative to nuclear energy. U-233 is Th-232 -> Th-233 -> Pa-233 -> U-233). The half-life of thorium 232, its most abundant isotope, is 14 billion years, or about as old as the universe. This material naturally requires similar stringent security measures used for plutonium storage for obvious reasons. Of course, it gammas to come back. The Th-U fuel cycle has some intriguing capabilities over the traditional U-Pu cycle. This normally emits an electron and an anti-neutrino ( ν ) by β decay to become Pa . And because of the complexity of problems listed below, thorium reactors are far more expensive than uranium fueled reactors. U-232 has a 70 year half-life so it takes a long time for these IN2P3 Uranium-233 has an extremely long half-life of 159,000 years, but too short for be still present on Earth. When non-fissionable thorium is mixed with either fissionable plutonium or uranium-235, it captures a neutron and converts to uranium-233, which itself is fissionable. In deep seawaters the isotope 230 Th makes up to 0.04% of natural thorium. A total of two tons of uranium-233 were manufactured in the United States. In these, fuel is not cast into pellets, but is rather Thorium doesnât work as well as U-Pu in a fast reactor. Contribute to davidfetter/website development by creating an account on GitHub. This isotope is more hazardous than the U-235 used in conventional reactors, he adds, because it produces U-232 as a side effect (half life: 160,000 years), on top of ⦠The 90th element, Thorium, has only one isotope that made it to our planet, Th-232 with a half life of 40 billion years. How is Thorium a Fuel? obtaining bomb material is not. Since the thorium process is so efficient, the reduced nuclear waste is only about 400 tons from US thorium reactors per year. But Molten salt reactors are amazing. The main advantage of thorium is that the waste has a half-life on the ⦠Pingback: The delusion of thorium â Beyond Nuclear International « nuclear-news, Pingback: The delusion of thorium â Beyond Nuclear International « Antinuclear, The delusion of thorium â Beyond Nuclear International « nuclear-news, The delusion of thorium â Beyond Nuclear International « Antinuclear. Also, thoriumâs small nuclear waste only has a half-life of 300 years, not 10,000 years. absorbed in the fuel in a traditional (thermal) type of reactor. Bi-212 also causes problems. dissolved in a vat of liquid salt. The nuclear industry is quite conservative, This is because its parent 238 U is soluble in water, but 230 Th is insoluble and precipitates into the sediment. The longstanding effort to produce these reactors cost the U.S. taxpayers billions of dollars, while billions more dollars are still required to dispose of the highly toxic waste emanating from these failed trials. Deploying new uranium-based nuclear reactors would likely happen much more rapidly and at a substantially lower cost. The DOE Office of Environmental Management now considers the disposal of this uranium-233 to be ‘an unfunded mandate’. By Thorium is therefore called fertile, whereas U-233 is called fissile. Mini-PRIMER on THE THORIUM CONCEPT. This is irrelevant for fluid-fueled reactors discussed below. That means no matter how many thorium nuclei are packed together, they can not go critical. in the not-too-distant futureâ¦. It was in poor condition. Investigators reported an environmental release from many of the 1,100 containers could ‘… be expected to occur within the next five years because some of the packages are approaching 30 years of age and have not been regularly inspected.’, The DOE determined that this building had “Deteriorated beyond cost-effective repair and significant annual costs would be incurred to satisfy both current DOE storage standards, and to provide continued protection against potential nuclear criticality accidents or theft of the material.”. Synthetic isotopes have been prepared; thorium-229 (7,880-year half-life), formed in the decay chain originating in the synthetic actinoid element neptunium, serves as a tracer for ordinary thorium (thorium-232). So for reactors that Reprocessing, as conducted at La Hague in France, involves exposing workers to toxic radioisotopes and still produces high volumes of radioactive waste. neutrons, it will undergo a series of nuclear reactions until it eventually emerges as an isotope of successfully tested. The vast majority of existing or proposed nuclear reactors, however, use enriched uranium best suited for Molten Salt Reactors, which are discussed on their own page as Then, it will decay directly to pure U-233. Thorium reactors work by breeding Th-232 through Protactinium-233 (27.4 day half life) and into Uranium-233, which is fissile. Thorium-fueled reactors, on the other hand, are fuel-efficient, almost perfectly so, but that comes at the end of a three-phase process, with the first phase shared by thorium ⦠cycle. publicly known that even reactor-grade plutonium can be made into a bomb if done carefully. So there is an extraordinarily complex, dangerous and expensive preliminary process to kick-start a fission process in a thorium reactor. That still means hundreds of years of waste. avoiding plutonium altogether, thorium cycles are superior in this regard. ... much much safer in terms of what do do with the discarded waste....half-life trivial in comparison. well as in summary below. Dr. Helen Mary Caldicott is an Australian physician, author, and anti-nuclear advocate who has founded several associations dedicated to opposing the use of nuclear power, depleted uranium munitions, nuclear weapons, nuclear weapons proliferation, and military action in general. But Pa-233 has a 27 day half-life, so once the [wikipedia] (MSRE). Note, however, that the gammas come from the decay chain of U-232, not All of the remaining thorium isotopes have half-lives that are less than thirty days and the majority of these have half-lives that are less than ten minutes. (bigger than uranium) atoms like Plutonium, Americium, Curium, etc. Let us start with the basic nuclear properties of Thorium, which present some problems for a reactor designer. This waste fuel is highly radioactive and the culprits â these high-mass isotopes â have half-lives of many thousands of years. During the fission process, two things happen to the uraniu⦠Additionally, Th is quite inert, making it difficult to chemically process. As Australia is grappling with the notion of introducing nuclear power into the country, it seems imperative the general public understand the intricacies of these technologies so they can make informed decisions. She is founding president of Beyond Nuclear. has downsides as well. It takes about the same amount of uranium-233 as plutonium-239 â six kilos â to fuel a nuclear weapon. Whoâs going to start the startup on these? Technetium 99 has a half-life of 300,000 years and iodine 129 a half-life of 15.7 million years. ability to productively discuss and debate thorium with knowledge of the basics. stealing spent fuel are largely reduced by Th, but the possibility of the owner of a Th-U reactor It is estimated to be about four times more abundant than uranium in the Earthâs crust. handful have used thorium. uranium called U-233, which will readily split and release energy next time it absorbs a neutron. waste is safe for a few times this, weapons are out of the question. These gamma rays are very hard to shield, requiring more expensive major health concern of long-term nuclear waste. Normally, Pa is passed into the fission product waste in the THOREX process, which could have long term ⦠Thorium cycles exclusively allow thermal breeder reactors (asopposed to fast breeders). be extremely safe, proliferation resistant, resource efficient, environmentally superior (to Plutonium has a shorter half-life of about 24,000 years compared to Uranium-235's half-life of just over 700 million years. However, contrary to proponentâs claims processing removes fission product neutron poisons and allows online refueling (eliminating the need So, expect this energy source to become a big deal It takes almost a year after the reactor shutdown for all of the protactinium-233 to transform into uranium-233. Isotope 232 Th belongs to primordial nuclides and ⦠One of the biggest is that a much higher fuel burn-up reduces plutonium waste by more than 80%. While uranium enrichment is already very expensive, the reprocessing of spent nuclear fuel from uranium powered reactors is enormously expensive and very dangerous to the workers who are exposed to toxic radioactive isotopes during the process. much detail in his autobiography, The First Nuclear opposed to fast breeders). Thorium is a naturally occurring element discovered in 1828 and named after Thor, the Norse god of thunder. The half-life of thorium-234 is only 24 days. Four commercial thorium reactors were constructed, all of which failed. Reactors that use thorium are operating on whatâs called the Thorium-Uranium (Th-U) fuel Spent fuel is thermally hot as well as highly radioactive and requires remote handling and shielding. The spent U-235 from the reactor contains very radioactive isotopes with a half-life of thousands of years, so the waste has to be stored safely for up to 10,000 years. Thus, Th-U waste will be less toxic on the 10,000+ heat from these gammas makes weapon fabrication difficult, as it is hard to keep the weapon pit from They can actually burn up more radioactive waste than they produce. Plutonium has a shorter half-life of about 24,000 years compared to Uranium-235's half-life ⦠But uranium-233 is also very efficient fuel for nuclear weapons. The problem with already like 4 startups working on them, and China is developing them as well). Uranium 232 has a half-life of 68.9 years, and its daughter radionuclides emit intense, highly penetrating gamma rays that make the material difficult to handle. Thorium fuel is a bit harder to prepare. Current and exotic designs can theoretically accommodate thorium. It is It is, therefore, necessary to mix thorium with either enriched uranium-235 (up to 20 per cent enrichment) or with plutonium â both of which are innately fissionable â to get the process going. U-235 for reactivity boosts, which means the nuclear fuel resources on Earth can be extended by 2 Besides avoiding plutonium, Thorium has additional self-protection from the hard gamma rays emitted Half a century ago, Oak Ridge National Lab in Tennessee successfully ran an experimental reactor that demonstrated feasibility. Thermal breeding is perhaps Thorium As Nuclear Fuel: the good and the bad, Computing the energy density of nuclear fuel, Molten Salt Reactor Experiment But it is not a fissile isotope. Thorium-bearing minerals and not as much Uranium. It is estimated that it will take over one million dollars per kilogram to dispose of the seriously deadly material. ... and with a half-life of over 24,000 years, it's tricky to store and dispose of. Pa-233 is a pretty strong neutron absorber, so the MSBR (basically the LFTR) has to extract it from the core once it is produced and let it ⦠Also, the test reactor of this type in the 1960s called the Molten Salt Reactor Experiment All of these isotopes are unstable (radioactive), but only 232 Th is relatively stable with half-life of 14 billion years, which is comparable to the age of the Earth (~4.5×10 9 years). Thorium is generally accepted as proliferation resistant compared to U-Pu cycles. through a heat exchanger to bring the heat out to a turbine and make electricity. Online chemical None of these reactors operate today, but Oak Ridge had a (Photo: Jean-Marie Taillat for WikiMedia Commons), Vast quantities of highly acidic, highly radioactive liquid waste then remain to be disposed of. (Only 6 kilograms of plutonium-239 can fuel a nuclear weapon, while each reactor makes 250 kilos of plutonium per year. invariably produces some U-232, which decays to Tl-208, which has a 2.6 MeV gamma ray decay mode. Thorium itself will not split and release energy. If 232 Th is loaded in the nuclear reactor, the nuclei of 232 Th absorb a neutron and become nuclei of 233 Th. For more information, see the Beyond Nuclear thorium fact sheet. This week, Dr. Caldicott will receive a Lifetime Achievement Award from the U.S. based Physicians for Social Responsibility, one of the organizations she founded. Thorium reactors also produce uranium-232, which decays to an extremely potent high-energy gamma emitter that can penetrate through one metre of concrete, making the handling of this spent nuclear fuel extraordinarily dangerous. Irradiated Thorium is more dangerously radioactive in the short term. The chain reaction heats the salt, which naturally convects Thorium dioxide melts at 550 degrees higher Thorium is only weakly radioactive. Although thorium advocates say that thorium reactors produce little radioactive waste, they simply produce a different spectrum of waste to those from uranium-235. The truth is, thorium is not a naturally fissionable material. It competed with the liquid metal cooled fast breeder reactors Later, the radioactive fuel would be removed from the reactor and reprocessed to separate out the uranium-233 from the contaminating fission products, and the uranium-233 will then be mixed with more thorium to be placed in another thorium reactor. Waste Storage (U-235) or reprocessed plutonium (Pu-239) as fuel (in the Uranium-Plutonium cycle), and only a Soil contains an average of around 6 parts per million (ppm) of thorium. orders of magnitude without some of the complications of fast reactors. Thorium cycles exclusively allow thermal breeder reactors (as High-level radioactive waste primarily is uranium fuel that has been used in a nuclear power reactor and is "spent," or no longer efficient in producing electricity. On this page youâll learn some details about these and leave with the Rather, when it is exposed to high-quality solid fuel. traditional nukes, as well as to fossil fuel obviously), and maybe even cheap. In the thorium cycle, fuel is formed when Th captures a neutron (whether in a fast reactor or thermal reactor) to become Th . This makes stealing Thorium based fuels more challenging. Alvin Weinberg discusses the history of this project in for extended amounts of time. By this Naturally, it takes some time for enough uranium-233 to accumulate to make this particular fission process spontaneously ongoing. Half-life of 233 Pa. Thorium 232 is âonlyâ a fertile material and the main problem can be directly in the breeding of fissile uranium 233. Thorium is a basic element of nature, like Iron and Uranium. chemically separated shortly after it is produced and removed from the neutron flux (the path to While U-233 an excellent fuel in This still includes many dangerous alpha and beta emitters, and isotopes with extremely long half-lives, including iodine-129 (half-life of 15.7 million years). due to U-232 as discussed above. Thorium exists in nature in a single isotopic form â T⦠These reactors could The U.S. tried for 50 years to create thorium reactors, without success. More neutrons are released per neutronabsorbed in the fuel in a traditional (thermal) type of reactor According to questions we have received, proponents claim that thorium reactors produce less waste and its half-life is âonlyâ a few hundred years rather than thousands. The half-life of 233 Th is approximately 21.8 minutes. [wikipedia], Molten Salt Reactor Experiment [wikipedia], Nuclear Power is our gateway to a prosperous future, Liquid Fluoride Thorium Reactor [wikipedia], Special May 2016 Edition of Nuclear Technology on Thorium. Era [amazon.com], and there is more info available all over the internet. When money is at stake, itâs difficult to get people to change from the norm. In nature, virtually all thorium is thorium-232, and has a half-life of about 14.05 billion years. spent fuel handling and/or reprocessing. Can Consume Nuclear Waste. An Energy Department safety investigation recently found a national repository for uranium-233 in a building constructed in 1943 at the Oak Ridge National Laboratory. Although thorium advocates say that thorium reactors produce little radioactive waste, they simply produce a spectrum of waste that's different from those from uranium 235, which includes many dangerous alpha and beta emitters and isotopes with extremely long half-lives, including technetium 99, with a half-life of 300,000 years, and iodine 129, with a half-life of 15.7 million years. other things). Compared to uranium reactors, thorium reactors produce far less waste, and the waste is much less radioactive with a much shorter half-life. Chris Coles December 29, 2020 02:56 AM. Finally, unlike U235, thorium is an efficient neutron absorber and producer. It is found in small amounts in most rocks and soils, where it is about three times more abundant than uranium. melting due to its own heat. Before these fuel rods are used, they are only slightly radioactive and may be handled without special shielding. One-millionth of a gram of plutonium, if inhaled, is carcinogenic.). This article originally appeared on Independent Australia and is republished with kind permission of the author. to be used to fuel a nuclear chain reaction that can run a power plant and make electricity (among require excellent neutron economy (such as breed-and-burn concepts), Thorium is not ideal. (Just kidding, there are The one hypothetical proliferation concern with Thorium fuel though, is that the Protactinium can be Thorium-232 is useful in breeder reactors because on capturing slow-moving neutrons it decays into fissionable uranium-233. and the biggest problem with Thorium is that we are lacking in operational experience with it. MSR reactors can be an effective way of getting rid of highly radioactive waste. (LMFBRs) for federal funding and lost out. (Fast-spectrum molten salt reactors (FS-MSR) can use all isotopes of uranium, not just the 0.7% U-235 in natural uranium â with all the safety and stability of MSR.) Thus, the quantity of U-233 does not change and abundant thorium is consumed in what is called the thorium fuel cycle. Thorium advocates say that thorium reactors produce little radioactive waste, however, they simply produce a different spectrum of waste from traditional reactors, including many dangerous isotopes with extremely long half-lives. temperatures than traditional Uranium dioxide, so very high temperatures are required to produce These transuranics are the is the molten salt reactor (MSR), or as one particular MSR is commonly known on the internet, the So concerns over people We donât have as much experience with Th. 4 And with todayâs reactor designs, which in the U.S. are fairly outdated, small disruptions in the process can also lead to catastrophic overheating and meltdowns. In other words, the thorium nucleus is very stable, with an extremely long shelf-life. It was an unmitigated disaster, as are many other nuclear enterprises undertaken by the nuclear priesthood and the U.S. Government. The main whatisnuclear.com website. The U.S. Department of Energy (DOE) has already, to its disgrace, ‘lost track’ of 96 kilograms of uranium-233. Although thorium advocates say that thorium reactors produce little radioactive waste, they simply produce a different spectrum of waste to those from uranium-235. Exotic, but Reduced nuclear waste. What about a thorium reactor design?? from U-232 itself. No wonder the U.S. nuclear industry gave up on thorium reactors in the 1980s.
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