One of the biggest is that a much higher fuel burn-up reduces plutonium waste by more than 80%. major health concern of long-term nuclear waste. waste is safe for a few times this, weapons are out of the question. And because of the complexity of problems listed below, thorium reactors are far more expensive than uranium fueled reactors. This material naturally requires similar stringent security measures used for plutonium storage for obvious reasons. chemically separated shortly after it is produced and removed from the neutron flux (the path to The truth is, thorium is not a naturally fissionable material. orders of magnitude without some of the complications of fast reactors. 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. dissolved in a vat of liquid salt. 4 And with today’s reactor designs, which in the U.S. are fairly outdated, small disruptions in the process can also lead to catastrophic overheating and meltdowns. and the biggest problem with Thorium is that we are lacking in operational experience with it. (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. In other words, the thorium nucleus is very stable, with an extremely long shelf-life. The vast majority of existing or proposed nuclear reactors, however, use enriched uranium Thorium is generally accepted as proliferation resistant compared to U-Pu cycles. These gamma rays are very hard to shield, requiring more expensive The Th-U cycle successfully tested. Also, the 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). from U-232 itself. The main website. 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. spent fuel handling and/or reprocessing. require excellent neutron economy (such as breed-and-burn concepts), Thorium is not ideal. We don’t have as much experience with Th. This is because its parent 238 U is soluble in water, but 230 Th is insoluble and precipitates into the sediment. Era [], and there is more info available all over the internet. Molten-salt reactors are particularly well-suited for the thorium fuel cycle. The U.S. Department of Energy (DOE) has already, to its disgrace, ‘lost track’ of 96 kilograms of uranium-233. processing removes fission product neutron poisons and allows online refueling (eliminating the need Note, however, that the gammas come from the decay chain of U-232, not stealing spent fuel are largely reduced by Th, but the possibility of the owner of a Th-U reactor (U-235) or reprocessed plutonium (Pu-239) as fuel (in the Uranium-Plutonium cycle), and only a 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. It is best suited for Molten Salt Reactors, which are discussed on their own page as Soil contains an average of around 6 parts per million (ppm) of thorium. More neutrons are released per neutron test reactor of this type in the 1960s called the Molten Salt Reactor Experiment Thorium is only weakly radioactive. But it is not a fissile isotope. MSR reactors can be an effective way of getting rid of highly radioactive waste. 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. Mini-PRIMER on THE THORIUM CONCEPT. Thorium is a basic element of nature, like Iron and Uranium. Thorium itself will not split and release energy. 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. • 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 has 6 naturally occurring isotopes. Thorium reactors work by breeding Th-232 through Protactinium-233 (27.4 day half life) and into Uranium-233, which is fissile. 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. IN2P3 Uranium-233 has an extremely long half-life of 159,000 years, but too short for be still present on Earth. It was an unmitigated disaster, as are many other nuclear enterprises undertaken by the nuclear priesthood and the U.S. Government. The chain reaction heats the salt, which naturally convects The main advantage of thorium is that the waste has a half-life on the … On this page you’ll learn some details about these and leave with the Half a century ago, Oak Ridge National Lab in Tennessee successfully ran an experimental reactor that demonstrated feasibility. Current and exotic designs can theoretically accommodate thorium. It is estimated to be about four times more abundant than uranium in the Earth’s crust. 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. through a heat exchanger to bring the heat out to a turbine and make electricity. What about a thorium reactor design?? It competed with the liquid metal cooled fast breeder reactors Of course, it traditional nukes, as well as to fossil fuel obviously), and maybe even cheap. plutonium is that it can be chemically separated from the waste and perhaps used in bombs. While U-233 an excellent fuel in One of the biggest is that a much higher fuel burn-up reduces plutonium waste by more than 80%. 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 … Online chemical avoiding plutonium altogether, thorium cycles are superior in this regard. The U.S. tried for 50 years to create thorium reactors, without success. Chris Coles December 29, 2020 02:56 AM. [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. 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). 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. Thorium dioxide melts at 550 degrees higher absorbed in the fuel in a traditional (thermal) type of reactor. The one hypothetical proliferation concern with Thorium fuel though, is that the Protactinium can be The nuclear industry is quite conservative, Although thorium advocates say that thorium reactors produce little radioactive waste, they simply produce a different spectrum of waste to those from uranium-235. Thorium cycles exclusively allow thermal breeder reactors (as Plutonium has a shorter half-life of about 24,000 years compared to Uranium-235's half-life … year time scale. Liquid Fluoride Thorium Reactors (LFTR). DR. publicly known that even reactor-grade plutonium can be made into a bomb if done carefully. Then, it will decay directly to pure U-233. How is Thorium a Fuel? Thorium cycles exclusively allow thermal breeder reactors (asopposed to fast breeders). It is estimated that it will take over one million dollars per kilogram to dispose of the seriously deadly material. ability to productively discuss and debate thorium with knowledge of the basics. 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. For more information, see the Beyond Nuclear thorium fact sheet. Who’s going to start the startup on these? None of these reactors operate today, but Oak Ridge had a 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. (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.) Additionally, Th is quite inert, making it difficult to chemically process. Posted on November 3, 2019 by beyondnuclearinternational. This then emits another electron and anti-neutrino by a second β decay to become U , the fuel: This article originally appeared on Independent Australia and is republished with kind permission of the author. However, contrary to proponent’s claims ... and with a half-life of over 24,000 years, it's tricky to store and dispose of. More neutrons are released per neutronabsorbed in the fuel in a traditional (thermal) type of reactor So concerns over people 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. But Molten salt reactors are amazing. Thorium is therefore called fertile, whereas U-233 is called fissile. The half-life of 233 Th is approximately 21.8 minutes. Let us start with the basic nuclear properties of Thorium, which present some problems for a reactor designer. Technetium 99 has a half-life of 300,000 years and iodine 129 a half-life of 15.7 million years. Naturally, it takes some time for enough uranium-233 to accumulate to make this particular fission process spontaneously ongoing. So, expect this energy source to become a big deal Thorium is very insoluble, which is why it is plentiful in sands but not in seawater, in contrast to uranium. Thorium reactors have long been proposed as a cleaner, safer alternative to nuclear energy. The thorium-based fuel also comes with other key benefits. This means that if the fuel is 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. Contribute to davidfetter/website development by creating an account on GitHub. No wonder the U.S. nuclear industry gave up on thorium reactors in the 1980s. Normally, Pa is passed into the fission product waste in the THOREX process, which could have long term … 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 … ... much much safer in terms of what do do with the discarded waste....half-life trivial in comparison. 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. Yes. 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). Thorium As Nuclear Fuel: the good and the bad, Computing the energy density of nuclear fuel, Molten Salt Reactor Experiment Thorium reactors are amongst those being suggested at this time. Bi-212 also causes problems. Instead of thorium, a Molten Salt Reactor can use uranium-235 or plutonium waste, from LWR and other reactors. If 232 Th is loaded in the nuclear reactor, the nuclei of 232 Th absorb a neutron and become nuclei of 233 Th. challenging route, one could obtain weapons material.