Spent fuel is thermally hot as well as highly radioactive and requires remote handling and shielding. Note, however, that the gammas come from the decay chain of U-232, not test reactor of this type in the 1960s called the Molten Salt Reactor Experiment Additionally, Th is quite inert, making it difficult to chemically process. By this The MSRE successfully proved that the concept has merit and can be operated 4 And with today’s reactor designs, which in the U.S. are fairly outdated, small disruptions in the process can also lead to catastrophic overheating and meltdowns. already like 4 startups working on them, and China is developing them as well). Thorium dioxide melts at 550 degrees higher 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. No wonder the U.S. nuclear industry gave up on thorium reactors in the 1980s. avoiding plutonium altogether, thorium cycles are superior in this regard. [wikipedia] (MSRE). Besides avoiding plutonium, Thorium has additional self-protection from the hard gamma rays emitted in the not-too-distant future…. Waste Storage For more information, see the Beyond Nuclear thorium fact sheet. Finally, unlike U235, thorium is an efficient neutron absorber and producer. dissolved in a vat of liquid salt. This material naturally requires similar stringent security measures used for plutonium storage for obvious reasons. Plutonium has a shorter half-life of about 24,000 years compared to Uranium-235's half-life … The main whatisnuclear.com website. neutrons, it will undergo a series of nuclear reactions until it eventually emerges as an isotope of This means that the contaminants could be chemically separated and the material is the molten salt reactor (MSR), or as one particular MSR is commonly known on the internet, the Current and exotic designs can theoretically accommodate thorium. heat from these gammas makes weapon fabrication difficult, as it is hard to keep the weapon pit from But uranium-233 is also very efficient fuel for nuclear weapons. 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.”. IN2P3 Uranium-233 has an extremely long half-life of 159,000 years, but too short for be still present on Earth. Then, it will decay directly to pure U-233. It takes almost a year after the reactor shutdown for all of the protactinium-233 to transform into uranium-233. These gamma rays are very hard to shield, requiring more expensive This normally emits an electron and an anti-neutrino ( ν ) by β decay to become Pa . Molten-salt reactors are particularly well-suited for the thorium fuel cycle. Current uranium waste is 30,000 tons per year. And because of the complexity of problems listed below, thorium reactors are far more expensive than uranium fueled reactors. One especially cool possibility suitable for the thermal-breeding capability of the Th-U fuel cycle Up and coming nuclear reactor powerhouses China and India both have substantial reserves of Thorium exists in nature in a single isotopic form – T… Update: See our full page on Molten Salt Reactors for more info. The problem with Like Uranium, its properties allow it On this page you’ll learn some details about these and leave with the She is founding president of Beyond Nuclear. ... much much safer in terms of what do do with the discarded waste....half-life trivial in comparison. Thermal breeding is perhaps (LMFBRs) for federal funding and lost out. Rather, when it is exposed to traditional nukes, as well as to fossil fuel obviously), and maybe even cheap. DR. Liquid Fluoride Thorium Reactors (LFTR). for extended amounts of time. So concerns over people Thorium reactors work by breeding Th-232 through Protactinium-233 (27.4 day half life) and into Uranium-233, which is fissile. (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. The truth is, thorium is not a naturally fissionable material. One-millionth of a gram of plutonium, if inhaled, is carcinogenic.). from U-232 itself. This makes stealing Thorium based fuels more challenging. Bi-212 also causes problems. [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. Can Consume Nuclear Waste. The nuclear industry is quite conservative, Thorium is generally accepted as proliferation resistant compared to U-Pu cycles. temperatures than traditional Uranium dioxide, so very high temperatures are required to produce Thorium fuel is a bit harder to prepare. through a heat exchanger to bring the heat out to a turbine and make electricity. Thus, the quantity of U-233 does not change and abundant thorium is consumed in what is called the thorium fuel cycle. 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 … Instead of thorium, a Molten Salt Reactor can use uranium-235 or plutonium waste, from LWR and other reactors. Deploying new uranium-based nuclear reactors would likely happen much more rapidly and at a substantially lower cost. Thorium itself will not split and release energy. obtaining bomb material is not. ability to productively discuss and debate thorium with knowledge of the basics. But Molten salt reactors are amazing. Thorium is a basic element of nature, like Iron and Uranium. Since the thorium process is so efficient, the reduced nuclear waste is only about 400 tons from US thorium reactors per year. ... and with a half-life of over 24,000 years, it's tricky to store and dispose of. much detail in his autobiography, The First Nuclear (bigger than uranium) atoms like Plutonium, Americium, Curium, etc. More neutrons are released per neutronabsorbed in the fuel in a traditional (thermal) type of reactor It takes about the same amount of uranium-233 as plutonium-239 – six kilos – to fuel a nuclear weapon. They can actually burn up more radioactive waste than they produce. 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. It is found in small amounts in most rocks and soils, where it is about three times more abundant than uranium. opposed to fast breeders). In deep seawaters the isotope 230 Th makes up to 0.04% of natural thorium. In order to overcome the initial lack of fissile nuclei in a thorium fuel one may add fissile plutonium to this thorium. 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. 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. Thorium is only weakly radioactive. These reactors could year time scale. Reduced nuclear waste. to be used to fuel a nuclear chain reaction that can run a power plant and make electricity (among 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. 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. This is irrelevant for fluid-fueled reactors discussed below. Thorium is therefore called fertile, whereas U-233 is called fissile. challenging route, one could obtain weapons material. gammas to come back. best suited for Molten Salt Reactors, which are discussed on their own page as 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. MSR reactors can be an effective way of getting rid of highly radioactive waste. handful have used thorium. Thorium reactors are amongst those being suggested at this time. spent fuel handling and/or reprocessing. But Pa-233 has a 27 day half-life, so once the A total of two tons of uranium-233 were manufactured in the United States. We don’t have as much experience with Th. This article originally appeared on Independent Australia and is republished with kind permission of the author. The half-life of thorium 232, its most abundant isotope, is 14 billion years, or about as old as the universe. 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. So there is an extraordinarily complex, dangerous and expensive preliminary process to kick-start a fission process in a thorium reactor. U-233 is Th-232 -> Th-233 -> Pa-233 -> U-233). During the fission process, two things happen to the uraniu… Thorium-bearing minerals and not as much Uranium. 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. More neutrons are released per neutron waste is safe for a few times this, weapons are out of the question. 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 … That still means hundreds of years of waste. Mini-PRIMER on THE THORIUM CONCEPT. None of these reactors operate today, but Oak Ridge had a Posted on November 3, 2019 by beyondnuclearinternational. U-232 has a 70 year half-life so it takes a long time for these The chain reaction heats the salt, which naturally convects chemically separated shortly after it is produced and removed from the neutron flux (the path to That means no matter how many thorium nuclei are packed together, they can not go critical. Yes. 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. 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. Thorium-232 is useful in breeder reactors because on capturing slow-moving neutrons it decays into fissionable uranium-233. 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. The Th-U cycle 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). (Just kidding, there are Thorium cycles exclusively allow thermal breeder reactors (asopposed to fast breeders). The U.S. tried for 50 years to create thorium reactors, without success. 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). The main advantage of thorium is that the waste has a half-life on the … processing removes fission product neutron poisons and allows online refueling (eliminating the need This means that if the fuel is So, expect this energy source to become a big deal And very importantly, thorium is not fissile. It competed with the liquid metal cooled fast breeder reactors However, contrary to proponent’s claims require excellent neutron economy (such as breed-and-burn concepts), Thorium is not ideal. 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). These transuranics are the Technetium 99 has a half-life of 300,000 years and iodine 129 a half-life of 15.7 million years. (U-235) or reprocessed plutonium (Pu-239) as fuel (in the Uranium-Plutonium cycle), and only a It is By This waste fuel is highly radioactive and the culprits – these high-mass isotopes – have half-lives of many thousands of years. Normally, Pa is passed into the fission product waste in the THOREX process, which could have long term … 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. Half a century ago, Oak Ridge National Lab in Tennessee successfully ran an experimental reactor that demonstrated feasibility. reprocessed, reactors could be fueled without mining any additional orders of magnitude without some of the complications of fast reactors. to shut down for fuel management, etc.). other things). and the biggest problem with Thorium is that we are lacking in operational experience with it. Plutonium has a shorter half-life of about 24,000 years compared to Uranium-235's half-life of just over 700 million years. 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. Thorium doesn’t work as well as U-Pu in a fast reactor. 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. So for reactors that Thorium reactors have long been proposed as a cleaner, safer alternative to nuclear energy. Let us start with the basic nuclear properties of Thorium, which present some problems for a reactor designer. 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. U-235 for reactivity boosts, which means the nuclear fuel resources on Earth can be extended by 2 • 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. The one hypothetical proliferation concern with Thorium fuel though, is that the Protactinium can be 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. Era [amazon.com], and there is more info available all over the internet. Thus, Th-U waste will be less toxic on the 10,000+ The half-life of 233 Th is approximately 21.8 minutes. invariably produces some U-232, which decays to Tl-208, which has a 2.6 MeV gamma ray decay mode. due to U-232 as discussed above. publicly known that even reactor-grade plutonium can be made into a bomb if done carefully. Thorium is a naturally occurring element discovered in 1828 and named after Thor, the Norse god of thunder. Nuclear reactor fuel contains ceramic pellets of uranium-235 inside of metal rods. The Th-U fuel cycle has some intriguing capabilities over the traditional U-Pu cycle. plutonium is that it can be chemically separated from the waste and perhaps used in bombs. What about a 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. Chris Coles December 29, 2020 02:56 AM. One of the biggest is that a much higher fuel burn-up reduces plutonium waste by more than 80%. would be much easier to work with. Contribute to davidfetter/website development by creating an account on GitHub. Isotope 232 Th belongs to primordial nuclides and … Reactors that use thorium are operating on what’s called the Thorium-Uranium (Th-U) fuel absorbed in the fuel in a traditional (thermal) type of reactor. The U.S. Department of Energy (DOE) has already, to its disgrace, ‘lost track’ of 96 kilograms of uranium-233. One of the biggest is that a much higher fuel burn-up reduces plutonium waste by more than 80%. be extremely safe, proliferation resistant, resource efficient, environmentally superior (to well as in summary below. Four commercial thorium reactors were constructed, all of which failed. 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. Who’s going to start the startup on these? The vast majority of existing or proposed nuclear reactors, however, use enriched uranium uranium called U-233, which will readily split and release energy next time it absorbs a neutron. high-quality solid fuel. Thorium As Nuclear Fuel: the good and the bad, Computing the energy density of nuclear fuel, Molten Salt Reactor Experiment When money is at stake, it’s difficult to get people to change from the norm. Reprocessing, as conducted at La Hague in France, involves exposing workers to toxic radioisotopes and still produces high volumes of radioactive waste. 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 … Compared to uranium reactors, thorium reactors produce far less waste, and the waste is much less radioactive with a much shorter half-life. 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. major health concern of long-term nuclear waste. has downsides as well. If 232 Th is loaded in the nuclear reactor, the nuclei of 232 Th absorb a neutron and become nuclei of 233 Th. melting due to its own heat. The uranium 233 produced in thorium reactors is contaminated with uranium 232, which is produced through several different neutron absorption pathways. Alvin Weinberg discusses the history of this project in Naturally, it takes some time for enough uranium-233 to accumulate to make this particular fission process spontaneously ongoing. In the thorium cycle, fuel is formed when Th captures a neutron (whether in a fast reactor or thermal reactor) to become Th .

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