That still means hundreds of years of waste. 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). to be used to fuel a nuclear chain reaction that can run a power plant and make electricity (among Technetium 99 has a half-life of 300,000 years and iodine 129 a half-life of 15.7 million years. 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 … [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. These reactors could (U-235) or reprocessed plutonium (Pu-239) as fuel (in the Uranium-Plutonium cycle), and only a spent fuel handling and/or reprocessing. Irradiated Thorium is more dangerously radioactive in the short term. The chain reaction heats the salt, which naturally convects But Pa-233 has a 27 day half-life, so once the And because of the complexity of problems listed below, thorium reactors are far more expensive than uranium fueled reactors. Plutonium has a shorter half-life of about 24,000 years compared to Uranium-235's half-life … 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. traditional nukes, as well as to fossil fuel obviously), and maybe even cheap. temperatures than traditional Uranium dioxide, so very high temperatures are required to produce 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. (Just kidding, there are Thorium is therefore called fertile, whereas U-233 is called fissile. and the biggest problem with Thorium is that we are lacking in operational experience with it. 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. handful have used thorium. U-232 has a 70 year half-life so it takes a long time for these 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. Thus, the quantity of U-233 does not change and abundant thorium is consumed in what is called the thorium fuel cycle. high-quality solid fuel. This makes stealing Thorium based fuels more challenging. These transuranics are the Protactinium-233 has a half-life of about 27 days, after which is beta-decays to uranium-233, which is fissile and has impressive properties. gammas to come back. cycle. the thermal spectrum, it is between U-235 and Pu-239 in the fast spectrum. Also, the Compared to uranium reactors, thorium reactors produce far less waste, and the waste is much less radioactive with a much shorter half-life. The main advantage of thorium is that the waste has a half-life on the … be extremely safe, proliferation resistant, resource efficient, environmentally superior (to Online chemical The truth is, thorium is not a naturally fissionable material. 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. 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. On this page you’ll learn some details about these and leave with the The one hypothetical proliferation concern with Thorium fuel though, is that the Protactinium can be (Fast-spectrum molten salt reactors (FS-MSR) can use all isotopes of uranium, not just the 0.7% U-235 in natural uranium — with all the safety and stability of MSR.) Thus, Th-U waste will be less toxic on the 10,000+ Thorium reactors have long been proposed as a cleaner, safer alternative to nuclear energy. Thorium is very insoluble, which is why it is plentiful in sands but not in seawater, in contrast to uranium. The MSRE successfully proved that the concept has merit and can be operated ability to productively discuss and debate thorium with knowledge of the basics. More neutrons are released per neutronabsorbed in the fuel in a traditional (thermal) type of reactor The main whatisnuclear.com website. DR. Can Consume Nuclear Waste. Thorium reactors are amongst those being suggested at this time. Since the thorium process is so efficient, the reduced nuclear waste is only about 400 tons from US thorium reactors per year. test reactor of this type in the 1960s called the Molten Salt Reactor Experiment plutonium is that it can be chemically separated from the waste and perhaps used in bombs. dissolved in a vat of liquid salt. Who’s going to start the startup on these? Mini-PRIMER on THE THORIUM CONCEPT. 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. Like Uranium, its properties allow it The half-life of 233 Th is approximately 21.8 minutes. Thorium cycles exclusively allow thermal breeder reactors (as Posted on November 3, 2019 by beyondnuclearinternational. During the fission process, two things happen to the uraniu… Thorium-232 is useful in breeder reactors because on capturing slow-moving neutrons it decays into fissionable uranium-233. 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.”. Thorium has 6 naturally occurring isotopes. It is found in small amounts in most rocks and soils, where it is about three times more abundant than uranium. One-millionth of a gram of plutonium, if inhaled, is carcinogenic.). 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. Update: See our full page on Molten Salt Reactors for more info. The problem with Also, thorium’s small nuclear waste only has a half-life of 300 years, not 10,000 years. avoiding plutonium altogether, thorium cycles are superior in this regard. Thermal breeding is perhaps Bi-212 also causes problems. The DOE Office of Environmental Management now considers the disposal of this uranium-233 to be ‘an unfunded mandate’. The Th-U fuel cycle does not irradiate Uranium-238 and therefore does not produce transuranic A total of two tons of uranium-233 were manufactured in the United States. 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 … The 90th element, Thorium, has only one isotope that made it to our planet, Th-232 with a half life of 40 billion years. Note, however, that the gammas come from the decay chain of U-232, not In order to overcome the initial lack of fissile nuclei in a thorium fuel one may add fissile plutonium to this thorium. Alvin Weinberg discusses the history of this project in Before these fuel rods are used, they are only slightly radioactive and may be handled without special shielding. So for reactors that Thorium is a basic element of nature, like Iron and Uranium. Thorium exists in nature in a single isotopic form – T… would be much easier to work with. Up and coming nuclear reactor powerhouses China and India both have substantial reserves of Instead of thorium, a Molten Salt Reactor can use uranium-235 or plutonium waste, from LWR and other reactors. (bigger than uranium) atoms like Plutonium, Americium, Curium, etc. It was an unmitigated disaster, as are many other nuclear enterprises undertaken by the nuclear priesthood and the U.S. Government. opposed to fast breeders). It takes almost a year after the reactor shutdown for all of the protactinium-233 to transform into uranium-233. neutrons, it will undergo a series of nuclear reactions until it eventually emerges as an isotope of While U-233 an excellent fuel in Liquid Fluoride Thorium Reactors (LFTR). (LMFBRs) for federal funding and lost out. This is irrelevant for fluid-fueled reactors discussed below. 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. So concerns over people other things). has downsides as well. In deep seawaters the isotope 230 Th makes up to 0.04% of natural thorium. Deploying new uranium-based nuclear reactors would likely happen much more rapidly and at a substantially lower cost. The Th-U cycle These gamma rays are very hard to shield, requiring more expensive By this Half-life of 233 Pa. Thorium 232 is “only” a fertile material and the main problem can be directly in the breeding of fissile uranium 233. The vast majority of existing or proposed nuclear reactors, however, use enriched uranium Half a century ago, Oak Ridge National Lab in Tennessee successfully ran an experimental reactor that demonstrated feasibility. U-235 for reactivity boosts, which means the nuclear fuel resources on Earth can be extended by 2 Current and exotic designs can theoretically accommodate thorium. By 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 … publicly known that even reactor-grade plutonium can be made into a bomb if done carefully. 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. Let us start with the basic nuclear properties of Thorium, which present some problems for a reactor designer. But uranium-233 is also very efficient fuel for nuclear weapons. 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. Although thorium advocates say that thorium reactors produce little radioactive waste, they simply produce a different spectrum of waste to those from uranium-235. Spent fuel is thermally hot as well as highly radioactive and requires remote handling and shielding. [wikipedia] (MSRE). processing removes fission product neutron poisons and allows online refueling (eliminating the need 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. It is invariably produces some U-232, which decays to Tl-208, which has a 2.6 MeV gamma ray decay mode. One of the biggest is that a much higher fuel burn-up reduces plutonium waste by more than 80%. absorbed in the fuel in a traditional (thermal) type of reactor. heat from these gammas makes weapon fabrication difficult, as it is hard to keep the weapon pit from The thorium-based fuel also comes with other key benefits. So, expect this energy source to become a big deal ... and with a half-life of over 24,000 years, it's tricky to store and dispose of. Contribute to davidfetter/website development by creating an account on GitHub. More neutrons are released per neutron Thorium is a naturally occurring element discovered in 1828 and named after Thor, the Norse god of thunder. Waste Storage successfully tested. The half-life of thorium-234 is only 24 days. from U-232 itself. require excellent neutron economy (such as breed-and-burn concepts), Thorium is not ideal. IN2P3 Uranium-233 has an extremely long half-life of 159,000 years, but too short for be still present on Earth. is the molten salt reactor (MSR), or as one particular MSR is commonly known on the internet, the Besides avoiding plutonium, Thorium has additional self-protection from the hard gamma rays emitted Then, it will decay directly to pure U-233. Yes. Chris Coles December 29, 2020 02:56 AM. waste is safe for a few times this, weapons are out of the question. 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. • 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. Current uranium waste is 30,000 tons per year. Thorium is only weakly radioactive. One especially cool possibility suitable for the thermal-breeding capability of the Th-U fuel cycle Four commercial thorium reactors were constructed, all of which failed. What about a thorium reactor design?? It is estimated to be about four times more abundant than uranium in the Earth’s crust. This is because its parent 238 U is soluble in water, but 230 Th is insoluble and precipitates into the sediment. It is estimated that it will take over one million dollars per kilogram to dispose of the seriously deadly material. In these, fuel is not cast into pellets, but is rather Molten-salt reactors are particularly well-suited for the thorium fuel cycle. stealing spent fuel are largely reduced by Th, but the possibility of the owner of a Th-U reactor No wonder the U.S. nuclear industry gave up on thorium reactors in the 1980s. U-233 is Th-232 -> Th-233 -> Pa-233 -> U-233). 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. obtaining bomb material is not. 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. reprocessed, reactors could be fueled without mining any additional Thorium itself will not split and release energy. We don’t have as much experience with Th. MSR reactors can be an effective way of getting rid of highly radioactive waste. Of course, it 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. 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. However, contrary to proponent’s claims How is Thorium a Fuel? 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). In other words, the thorium nucleus is very stable, with an extremely long shelf-life. The U.S. Department of Energy (DOE) has already, to its disgrace, ‘lost track’ of 96 kilograms of uranium-233. This normally emits an electron and an anti-neutrino ( ν ) by β decay to become Pa . It takes about the same amount of uranium-233 as plutonium-239 – six kilos – to fuel a nuclear weapon. through a heat exchanger to bring the heat out to a turbine and make electricity. for extended amounts of time. 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. best suited for Molten Salt Reactors, which are discussed on their own page as The uranium 233 produced in thorium reactors is contaminated with uranium 232, which is produced through several different neutron absorption pathways. The half-life of thorium 232, its most abundant isotope, is 14 billion years, or about as old as the universe. Isotope 232 Th belongs to primordial nuclides and … Thorium dioxide melts at 550 degrees higher None of these reactors operate today, but Oak Ridge had a Pingback: The delusion of thorium — Beyond Nuclear International « nuclear-news, Pingback: The delusion of thorium — Beyond Nuclear International « Antinuclear, The delusion of thorium — Beyond Nuclear International « nuclear-news, The delusion of thorium — Beyond Nuclear International « Antinuclear. 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. When money is at stake, it’s difficult to get people to change from the norm. Thorium cycles exclusively allow thermal breeder reactors (asopposed to fast breeders). Thorium is generally accepted as proliferation resistant compared to U-Pu cycles. Normally, Pa is passed into the fission product waste in the THOREX process, which could have long term … 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. Soil contains an average of around 6 parts per million (ppm) of thorium. Nuclear reactor fuel contains ceramic pellets of uranium-235 inside of metal rods. 4 And with today’s reactor designs, which in the U.S. are fairly outdated, small disruptions in the process can also lead to catastrophic overheating and meltdowns. She is founding president of Beyond Nuclear. But Molten salt reactors are amazing. Era [amazon.com], and there is more info available all over the internet. That means no matter how many thorium nuclei are packed together, they can not go critical. If 232 Th is loaded in the nuclear reactor, the nuclei of 232 Th absorb a neutron and become nuclei of 233 Th. Exotic, but ... much much safer in terms of what do do with the discarded waste....half-life trivial in comparison. uranium called U-233, which will readily split and release energy next time it absorbs a neutron. challenging route, one could obtain weapons material. It is, therefore, necessary to mix thorium with either enriched uranium-235 (up to 20 per cent enrichment) or with plutonium – both of which are innately fissionable – to get the process going. (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. Thorium fuel is a bit harder to prepare. They can actually burn up more radioactive waste than they produce. Reactors that use thorium are operating on what’s called the Thorium-Uranium (Th-U) fuel But it is not a fissile isotope. chemically separated shortly after it is produced and removed from the neutron flux (the path to much detail in his autobiography, The First Nuclear One of the biggest is that a much higher fuel burn-up reduces plutonium waste by more than 80%. It competed with the liquid metal cooled fast breeder reactors This waste fuel is highly radioactive and the culprits – these high-mass isotopes – have half-lives of many thousands of years. 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). year time scale. in the not-too-distant future…. This means that if the fuel is Finally, unlike U235, thorium is an efficient neutron absorber and producer. Plutonium has a shorter half-life of about 24,000 years compared to Uranium-235's half-life of just over 700 million years. This then emits another electron and anti-neutrino by a second β decay to become U , the fuel: already like 4 startups working on them, and China is developing them as well). Thorium doesn’t work as well as U-Pu in a fast reactor. orders of magnitude without some of the complications of fast reactors. to shut down for fuel management, etc.). major health concern of long-term nuclear waste. The U.S. tried for 50 years to create thorium reactors, without success. melting due to its own heat. And very importantly, thorium is not fissile. Thorium As Nuclear Fuel: the good and the bad, Computing the energy density of nuclear fuel, Molten Salt Reactor Experiment This article originally appeared on Independent Australia and is republished with kind permission of the author. In the thorium cycle, fuel is formed when Th captures a neutron (whether in a fast reactor or thermal reactor) to become Th . For more information, see the Beyond Nuclear thorium fact sheet. well as in summary below. This means that the contaminants could be chemically separated and the material 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. Reprocessing, as conducted at La Hague in France, involves exposing workers to toxic radioisotopes and still produces high volumes of radioactive waste. Reduced nuclear waste. The Th-U fuel cycle has some intriguing capabilities over the traditional U-Pu cycle. Although thorium advocates say that thorium reactors produce little radioactive waste, they simply produce a different spectrum of waste to those from uranium-235. Additionally, Th is quite inert, making it difficult to chemically process. 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. In nature, virtually all thorium is thorium-232, and has a half-life of about 14.05 billion years. The nuclear industry is quite conservative, Rather, when it is exposed to This material naturally requires similar stringent security measures used for plutonium storage for obvious reasons. Naturally, it takes some time for enough uranium-233 to accumulate to make this particular fission process spontaneously ongoing. So there is an extraordinarily complex, dangerous and expensive preliminary process to kick-start a fission process in a thorium reactor. Thorium-bearing minerals and not as much Uranium. Although thorium advocates say that thorium reactors produce little radioactive waste , they simply produce a different spectrum of waste to those from uranium-235, which includes many dangerous alpha and beta emitters and isotopes with extremely long half-lives including technetium 99 - half-life of 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.