One of the basic principles of the modern environmental movement is the simple mantra to “reduce, reuse, and recycle”. It is my intention to show in this essay that the technology of the liquid-fluoride reactor, coupled with the energy source thorium, make it possible to achieve these goals to a far greater degree than other nuclear energy technologies.
Introduction
Liquid-fluoride reactors are based upon the use of dissolved actinide fluoride salts in a carrier medium of low-absorption fluoride salt solvents. The most common formulations that have been considered and demonstrated for this mission are solvents based around low-melting point mixtures of beryllium fluoride (BeF2) and lithium fluoride (LiF) isotopically enhanced in the more-abundant component lithium-7. The actinide fluorides most commonly employed are thorium tetrafluoride (ThF4) and uranium tetrafluoride (UF4). LiF-BeF2 salt mixtures have very low neutron absorption properties, excellent heat capacity, stability under intense radiation, and the ability to dissolve appreciable amounts of thorium or uranium tetrafluoride.
Liquid and Solid Fluoride Salt Mixtures
Despite providing some degree of neutron moderation, LiF-BeF2 mixtures are not terribly good neutron moderators, thus liquid-fluoride reactors generally employ solid moderating materials in order to moderate neutrons to thermal energies. Graphite is most commonly employed, being abundant, relatively inexpensive, and chemically compatible with the salt. Graphite is not “wetted” by the fluoride salt and can be sealed in ways that limit the intrusion of fission product gases (especially xenon) into the structure of the graphite. Thorium as a nuclear fuel is not as well-known as uranium, but has properties that have special merit for nuclear use. Thorium also has a number of drawbacks for its use as a common nuclear fuel, but fortunately, by using thorium in fluoride form, nearly all of these drawbacks can be eliminated or strongly mitigated.
Thorium is common in the Earth’s crust, consisting of about 10 parts per million of common continental crust, approximately three to four times more common than uranium. Thorium is not fissile and consists of a single natural isotope (232) but thorium can be converted to a fissile fuel by the absorption of a neutron followed by a short period of beta decay. 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. 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. Uranium-233 produces enough neutrons from fission by a thermal neutron to sustain the continued conversion of thorium to energy, even accounting for normal losses, provided that the reactor is neutronically efficient.
Reducing the Production of Transuranic Nuclear Waste
One of the biggest concerns about today’s approach to nuclear power generation concerns our use of low-enrichment uranium (LEU) in solid-uranium-oxide-fueled light-water reactors. In these reactors, LEU fuel is irradiated by thermal neutrons and a significant amount of plutonium is produced from the uranium-238 that makes up 95-97% of the original fuel. Some of this plutonium is consumed as the solid-oxide fuel rod is further irradiated, but from the plutonium other isotopes of plutonium are formed by neutron capture, and then higher actinides like americium and curium are produced. From the small fraction of U-235 present in the fuel even some long-lived neptunium-237 is produced. After an irradiation period of 3-4 years, the fuel rod can no longer sustain addition irradiation and is removed and placed in a spent fuel pool for cooling as high-heating decay products move inevitably towards stability.
In our current approach to civilian nuclear power, these irradiated uranium oxide fuel rods are not reprocessed to separate and partition their different chemical components, but are instead bound for disposal in a deep geological repository in Nevada. There after several hundred years the transuranic actinides still present in the spent nuclear fuel will generate the bulk of the heating that dictates their spacing in the repository and its ultimate capacity. Furthermore, the transuranic actinides carry the vast majority of the radiotoxicity that repository licensers must deal with as they plan for the performance of the repository over the next ten thousand years. Reducing the amount of transuranic waste that will be sent to any future repository would therefore be an important goal of a future approach to civilian nuclear power generation, and this is eminently doable by using thorium in a liquid-fluoride reactor. Transuranic waste production can be drastically reduced by a clever combination of the inherent properties of the thorium fuel approach and by the flexibility of the liquid-fluoride fuel form. Thorium, with an atomic mass of 232, begins the nuclear energy generation process at least five neutron absorptions removed from the first transuranic isotope that could be generated. As previously mentioned, thorium-232 absorbs a neutron, transmuting to protactinium-233 and then uranium-233, which is fissile. In a thermal neutron spectrum, uranium-233 tends to fission 90% of the time it absorbs a thermal neutron. The other 10% of the time is converts to uranium-234. Another neutron absorption in uranium-234 leads to conversion to uranium-235, which is also fissile and represents another opportunity for destruction through fission. Uranium-235 fissions in a thermal neutron spectrum approximately 85% of the time, and the other 15% of the time is converted to uranium-236. Uranium-236 has a rather low neutron absorption cross-section, and only after absorbing a neutron is the first transuranic isotope of this approach produced: neptunium-237. Neptunium can be removed from the fluoride salt mixture readily by fluorination from NpF4, which is in solution to NpF6 which is gaseous. Thus, unlike our current approach to nuclear power where the majority of the fuel (97% U-238) is a single neutron absorption away from the production of the first transuranic isotope (Pu-239), in the thorium-based approach, the fuel is five neutron absorptions away from the production of a transuranic isotope, and in the course of those absorptions roughly 98.5% of the original fuel is removed by fission. Thus, by using thorium in the fluoride reactor rather than uranium in the solid-oxide reactor, it is possible to REDUCE the amount of transuranic material generated by a very large factor.
Reusing Nuclear Fuel
As previously mentioned, today’s approach to nuclear fuel employs low-enrichment uranium is solid-oxide form in zirconium cladding, cooling and moderated by ordinary water. As an oxide, uranium is quite chemically stable and able to achieve high temperatures without melting down. Unfortunately, as an oxide, uranium is also subject to the low thermal conductivities common to most all oxides, and therefore high temperatures at the centerline of the solid fuel element become an inevitable consequence of heat transfer out the surface of the fuel element. In fact, the centerline fuel temperature of a uranium oxide fuel element, relative to the melting temperature of uranium oxide, is one of the key geometrical constraints.
As uranium oxide fuel is irradiated, fission products and transuranics accumulate in the ceramic oxide matrix. Intense radiation from the fission process and the decay of fission products also damages the fuel structure, causing dislocations and swelling in the crystalline matrix. Especially damaging to the fuel element are in the in-growth of gaseous fission products such as xenon and krypton, which further distend and crack the fuel structure. One of the isotopes of xenon (135) has a huge appetite for thermal neutrons and causes control transients during the changing of power settings within the reactor. After a period of time the uranium oxide fuel element has been depleted of fuel, swollen, cracked, distended, inflated, and compromised by the fission process and must be removed before cladding failure leads to the loss of fission products and other radioactive isotopes to the water loop of the reactor system. Spent solid-oxide fuel rods must be replaced by new fuel rods and are sent to a cooling pond where decay heat can be removed. Although the spent fuel still contains large amounts of unused fuel in the form of both uranium and other actinides, that fuel cannot be accessed until a reprocessing program takes place that involves chemically changing the solid uranium oxide into a liquid uranium nitrate fuel form through the application of strong nitric acid. Then a combination of chemical processes in aqueous and hydrocarbon solvents takes place to separate gaseous fission products, other fission products, transuranics, and uranium from one another. The resulting waste streams from these processes can be utilized productively, but the cost is significant due to the aggressive chemical steps involved and the chemical intensiveness of the new forms. Many, many recycles of the fuel would be needed to “burn-down” the uranium-238 present in the original spent fuel to energy (through fission) and the costs involved in reprocessing dictate that spent nuclear fuel is rarely subjected to more than one or two recycles before it is disposed. Thorium and the fluoride reactor present an entirely different approach to fuel management that makes repeated recycling not only easy but economically advantageous. That is because nuclear fuel in the liquid fluoride form rather than in the solid oxide form has distinct advantages. It is already in a chemically stable form as a fluoride. There is no reagent to treat the fuel that will be favored over its current state. Thus it is protected from chemical attack, combustion, burning, or corrosion. But more importantly, as a fluid is it in a form where chemical processes can be employed directly to remove fission products or to add new fuel to compensate for burnup. Additionally, the ionic nature of liquid-fluoride salt renders the fuel essentially impervious to radiation damage. Despite the passage of large amounts of gamma radiation, neutron radiation, alpha radiation, etc. the fuel remains chemically unaltered and with a complete retention of its physical properties. Gaseous fission products, including the important fission product poison xenon-135, are effortlessly easy to remove from liquid-fluoride salt. They simply come out of solution in the pump bowl during the pumping of the fluid through the loop. This has the additional benefit of keeping pressures low and allowing the reactor to change power states rapidly without concern for the effect of xenon on power changes.
In a modern incarnation of the liquid-fluoride reactor, there are two separate fluoride salts in action in the reactor core: the “fuel salt” and the “blanket salt”. The fuel salt is a mixture of uranium tetrafluoride in the lithium-beryllium fluoride carrier solvent. The uranium consists predominantly of uranium-233 but also contains U-234 and U-236 at equilibrium levels of concentration. Depending on the reprocessing approach it also contains fission products in the form of fluorides. The blanket salt is a mixture of thorium tetrafluoride in the lithium-beryllium fluoride carrier solvent. The blanket salt geometrically surrounds the fuel salt with a graphite barrier between them. Fission in the fuel salt produces neutrons, roughly half of which end up in the blanket salt, transmuting thorium to uranium by neutron absorption followed by beta decay. The uranium formed in the blanket is removed by the simple process of fluorination, whereby uranium as a tetrafluoride in solution is converted to a hexafluoride that is gaseous. Since thorium has no gaseous hexafluoride, it is left behind while uranium is removed in this simple, one-step process. Then the fuel salt is “refueled” by this same stream of fresh uranium hexafluoride by converting it from hexafluoride back into tetrafluoride through contact with hydrogen gas. Thus freshly generated uranium is continuously removed from the blanket salt and added to the core salt, where it subsequently undergoes fission that continues the process all over again. By keeping fissile materials out of the blanket by continuous reprocessing, the blanket fluid can be kept relatively free of fission products. The fuel salt, on the other hand, will accumulate fission products as uranium fission continues. The most troublesome fission product, xenon, is effortlessly removed by pumping action, but other fission products will become of increasing concern. Samarium, neodymium, and other lanthanides are fission products whose neutron absorption cross-sections are significant enough to merit attention. In order to purify the fuel salt, the first step is to remove the uranium fuel by fluorination. Then the carrier salt (LiF-BeF2) can be distilled from fission product fluorides in a high-temperature still. The remaining fission product fluorides constitute the equivalent of “high-level waste” from fluoride reactor reprocessing. The extracted LiF-BeF2 is recombined with the uranium and reinserted into the reactor core for another cycle of power generation.
The fluid nature of the reactor fluids allow them to be used over and over again, removing only the products that have been generated during operation (uranium in the blanket, fission products in the fuel salt). This ability to continually REUSE the reactor nuclear fuels represents a profound advantage over the solid-fueled uranium approach.
Recycling the “Wastes” of Fission
Fission processes inevitably generate a variety of fission product elements and a large number of isotopes, most of which are neutron-rich and radioactive. The familiar double-humped distribution of fission products reflects the physical reality that each fission event results in two fission products, a “heavy” one and a “light” one. As each of these fission products tends to have many more neutrons than is needed for nuclear stability at its new “station” in life, rapid beta decay generally follows fission and most fission products assume a stable form quite quickly. When all of the isotopes of an element reach stability it can logically be asked whether or not they are worth chemical extraction and recycling to other, non-nuclear uses. Consider the case of xenon. Xenon is a noble gas and fission product that accounts for a fair fraction of the mass of fission products from uranium fission. Xenon has a variety of isotopes but the longest lived one (133) has only a half-life of 5.2 days. Therefore, proceeding on the rule-of-thumb that “ten half-lives and you’re gone” after 50 days of storage the xenon remaining from fission would be essentially non-radioactive. In a conventional solid-core reactor the xenon is bound up in the solid-oxide fuel rod and can only be extracted by chopping up and dissolving the fuel element, but in a fluoride reactor it is very easy to extract xenon. In fact, it will come out of solution with essentially no effort at all. Since xenon is a valuable gas, rather than vent the xenon to the atmosphere it can be separated from the krypton by cryogenic distillation and sold. NASA and commercial satellite operators, for instance, use xenon for ion engines for spacecraft. Future NASA missions to Mars that have considered using xenon have had to seriously consider whether the world supply of xenon was sufficient to make such missions possible. Xenon recovered from fission might increase xenon supply. Another valuable material from fission is neodymium. Within the last 20 years, the discovery of a neodymium-iron-boron alloy that can be used to make super-strong, super-light magnets has caused neodymium demand to increase tremendously. Ironically, one of the markets that is in greatest demand for neodymium is the wind turbine market. They need large electrical generators due to the diffuse nature of the wind energy source, and they need these electrical generators to be as lightweight as possible so that they can be mounted on top of large towers. Neodymium magnets are particularly suited to this demanding application. Neodymium is the third-most-common element generated from fission (by mass) and also achieves nuclear stability relatively quickly; its longest-lived isotope (147) has a half-life of 10.9 days. By aging the high-level waste from the distillation process in fluoride reactors appropriately, one could extract the neodymium trifluoride from the other fluorides and convert it to a metallic form through electrolysis or metallic reduction. The neodymium would then be available to sell to the burgeoning market. Xenon and neodymium represent two recycling opportunities where a period of “aging” is needed before the isotopes stabilize and partitioning and marketing is possible. But there are other isotopes in the “waste” stream of a fluoride reactor where the radioactive form of the isotope is the desirable and economic product. An example of this case is the life-saving medical isotope molybdenum-99. Currently, molybdenum-99 is generated in specially-designed medical isotope production reactors in Canada and rushed to medical facilities across North America. Mo-99 decays to technetium-99m, which is then extracted and introduced into human patients in order to facilitate diagnostic procedures. The market for Mo-99 is quite large, but in solid-fueled reactors, the Mo-99 produced by fission is not accessible until the fuel is reprocessed. Since that is an infrequent event in solid-fueled reactors, the overwhelming majority of the Mo-99 produced in such reactors is never productively utilized; rather it simply follows its decay chain to Tc-99. In a fluoride reactor, on the other hand, the fluid nature of the reactor makes it possible to continuously extract Mo-99 along with the other isotopes of molybdenum. Molybdenum forms a volatile hexafluoride much like uranium does, and when the fuel salt is fluorinated, U, Mo, and several other elements come out of solution as gaseous hexafluorides. These can then be separated on from another by distillation at different temperatures, much like crude oil is refined. The molybdenum could then be shipped to medical facilities, where the Mo-99 would decay to Tc-99m that could be chemically extracted and given to patients who need it. Xenon, molybdenum, and neodymium are three of the most common fission products but many others have value too. The fluid nature of the fluoride reactor makes RECYCLING of the so-called waste quite likely to be economically attractive in many circumstances.
Summary: Reduce, Reuse, Recycle
The environmental dictum of “reduce, reuse, recycle” has been considered in terms of the thorium-fueled, liquid-fluoride reactor and found to be a simple and unifying theme for the options that this technology makes available. Relative to a conventional, solid-fueled uranium reactor, one can drastically REDUCE the generation of transuranic actinides, REUSE the thorium and uranium fuel is a way that allows for complete consumption of the energy resources, and RECYCLE three of the most common fission products into economically useful and even life-saving applications. The thorium-fueled liquid fluoride reactor is worthy of significant further attention, investigation, and funding based on these and many other merits.
64 thoughts on “Thorium: Reduce, Reuse, Recycle”
When can I get a 25KW LFTR for my backyard? If I charge the electric power company for my unused power, how soon would I break even on my investment?
very encouraging research. Good luck with further writings! Too bad we wasted so much cash on nuclear fusion when thorium is such a cheap and abundant fuel.
Thanks for such insight and clarity regarding this technology. As an adjunct instructor of Physics I try to encourage my students to be open minded about nuclear power.
It is unfortunate that the media is so biased against nuclear power that the average citizen is afraid of this technology.
Our leaders lack the courage to educate the herd and move forward with technologies that can assure our energy independence. I continue to promote your writings and send letters to my government representatives.
My longstanding objection to nuclear power has always been its inherent danger, not least in the reprocessing or storage of radioactive waste. My daughter alerted me to the possibilities of Thorium by sending me a link to a recent article in The Daily Telegraph, the UK newspaper. It was the first I'd ever heard of this type of reactor, and I can see how important a development this would be. I shall be writing to members of our government to suggest that as we are about to commission new nuclear reactors, this is the way to go. I shall also be writing this month's blog (View From Trevadlock Cross) on the subject, though I don't think many people read it!
I think, though, that if you could come up with a really simple explanation that a baby could understand, it would be helpful in getting the message across.
This sounds like a great idea that solves some of the problems with the current light water technology. However, the devil is in the details, and this idea creates some new problems. For instance, non-recyclable fission products, with high dose rate and long half lives will be created. This material will need to be solidified and stored (where?) using remote handling, shielding, and licensed shipping container.
Injection rate of U233 into the reactor can affect the reaction rate. It needs to be proven that this can be controlled.
Old problems remain, such as the removal of decay heat under all conditions including 9.0 earthquakes and tsunami.
It is important to prove the concept in a methodical way. We need a small, relatively inexpensive, short project(s), find out what the problems and solutions are, and then build from there. Keep it simple using proven technology where ever possible.
I agree with the idea of the retro-fitting of the existing coal-fired powerplants and converting them over to this technology. But, get ready for the fight from to coal industry, as well as the existing nuclear power industries–both generation and support–because you are basically phasing out an antiquated and danger riddled technology (look at the recent reactor disasters in Japan) This alone should be the driving force to move into the 21st century with our nuclear power, as well. I agree with Rod Clemenson–FOR ONCE, LETS BE THE FIRST WITH THE BEST!!!!!
I first caught Kirk Sorensen on Dr. Kiki Science Hour on the Twit Network http://twit.tv. I've completely read read thru this site less some of the ORNL Documents as well as Barton's Nuclear Green Revolution site. I live in West Virginia now so LFTR would surely go over like a Lead Balloon in this Coal Producing State. I am a Navy Veteran who has served on a Nuclear Aircraft Carrier so I'm comfortable LIVING ON A NUKE!!
To address this thread I'm afraid the AEC/ERDA is not the answer especially as Industry/Government will attempt to introduce the Next Generation of Reactors. They will just botch it. Everyday I'm becoming a little more Libertarian, but I haven't drunk all that Cool Aide yet. Kirk's Market Place orientation is a great solution. Since GE and Westinghouse like the Razor / RazorBlade analogy to market and sell their Reactor/Refueling concept they're not in the LFTR game. It would be to their to their benefit to get behind this as Plutonium Breeding is a Multi-Human Generational process time wise and just plain too expensive. If the Westinghouse / GE Mathematical Strategic Business Forecasters plugged into the Sorensen vision they would make a lot more money. Capitalism is a Entrepreneurial process, it punishes the poor Entrepreneurs by failure and rewards the ones who forecast better the use of Capital and the Means of Production. It may very well be a case of Creative Destruction. These companies are just to deep into PWRs. The present/future companies will take on LFTR's for profit. If we go back to the Original Wigner/Weinberg we will see LFTRs as a Chemical Engineering/Company opportunity. (Kirk kudos to you for talking to anyone and everyone about this, so forgive me if I am stating any lobbying you've already done but haven't share with us). I'm talking about Union Carbide, Monsanto and Petroleum Refiners and all their associated Trade Associations. Just the extraction of Fluorine from stockpiles of Uranium Hexafluoride would be a dream business from all the above. Next Potential Brayton Cycle Turbine Manufacturers. Honeywell, Rolls Royce, Pratt & Whitney and Williams. If General Electric/SNECMA Jet Engine group is semi independent to pursue Brayton Cycle Engines they would be wise to jump onto this as well. GE is well known for their Natural Gas Compressor/Turbines to pump Natural Gas. Waste Management to transport the Stockpiles of Nuclear Wastes to Processors. Airplane Manufacturers and their suppliers are Ideal to Build LFTRs as well as General Motors Electro Motive Division, their Locomotive Building Division. Governor Elect Rick Snyder of Michigan an executive from Gateway Computers is open for business(High Tech Guy too). Greens such as Amory Lovins of the Rocky Mountain Institute should love this pitch. Kirk I do know you're not a fan of his. But Lovin's does have a concept of Small is Beautiful in Electric Power Generation. Small efficient generators mass produced for economic reduction of costs and placing them close to their Loads to reduce transition losses and bypass the building of more Transmission Lines. His misguided hate of Nuclear can probably turned around with your LFTR vision. Give Lovin's his due, he's one heck of a Promoter. If the Quads of World Energy Needs, Losses and Efficiency are brought to bare along with the Processing of Nuclear Wastes for LFTR fueling, safe sequestration I'm sure even he will get on board. If we revisit General Electric along with the United States Navy, just think about this. Propulsion Systems on Almost all Large Cruisers Ticonderoga Class, Destroyers Kidd Class,Destroyers Spruance Class are General Electric Gas Turbine with General Electric Reduction Gear Sets to turn the Propellers. Imagine all the JetFuel these ships burn and they burn a lot!!! It's certainly a lot more expensive now. LFTRs on these vessels would revolutionize the Fleet. Kirk in Ship Yards they use torches to open these ships all the time to take Big Things Out and put Big Things in. LFTR anyone!!! Hello GE….. When I was on the USS Nimitz CVN 68 we use to serve JP-7 to some of our gas turbine Destroyer Escorts all the time during underway replenishment, even the steam powered ships. In 1980 when Russian Gas Turbine Combatant Ships were following us around the Indian Ocean our Nuclear Powered Battle Group Rang Up 30 plus knots. Gas Turbine ships can go fast but not far and fast. We ran for 12 plus hour and we ran them out of gas then walked away. Now how's that for fuel/power density! The Nimitz Class has two 500 Megawatt Thermal Output Reactors. The Carrier Enterprise had a Thermal Output of 1.2 Gigawatts using 8 smaller submarine reactors about 140 Megawatts Thermal apiece. Kinda of like a Sorensen mini park of Electric Power LFTRs. A LFTR initial Fissile load would be an improvement by at least 35 times on the Uranium 235 alone not to mention all that Uranium 238 we lugged aroud, the Oxide, the Pressure Vessel that a PWR Nuke has. So the GE business for LFTR Naval Propulsion is compelling, or a GE Competitor. My last point of Naval History. In the 1930's General Motors Bid at a loss to develop and produce Diesel Engines for the United States Navy to put into Fleet Boat Submarines. GM was smart, these same diesels also were perfectly sized to go into the bread and butter business of Diesel Engines for Diesel/Electric Trains. Sooooo…. two-to-three 100 megawatt electric LFTRs retrofitted to a Gas Turbine Cruiser/Destroyer. Fulfill the Naval Propulsion contract. Assembly line the LFTRs for Power Generation.
I failed to see any discussion of reducing our energy requirements through conservation. If the US reduced its energy use to that of Europe, the whole nuclear industry could be shut down tomorrow. However, that is just dreaming; Americans will not voluntarily reduce their energy consumption. "The American way of life is non negotiable" has been the mantra of those who wish to maintain the situation where about 5% of the world population uses 24% of the worlds resources. I am not suggesting that the US reduce its standard of living to that of the Third World, but some perspective is in order. However, I do think that Thorium fueled reactors offer advantages and that they need to be considered.
Rob carroll, while i agree with you that conservation is crucial, I disagree with your statement 'the whole nuclear industry could be shut down tomorrow'. United states energy conservation isnt on trial here; viable energy production is.
Dear Kirk,
I am really amazed about this technology. I discovered it almost 3 years ago and I only want to say, keep up the good work. Will try to get the technology known to friends, neighbours politicians as well.
Greetings from Europe, Brussels.
Roeland
The "american way of life is not negotiable" is for me a political dud. By 1942 your grand-grand parents perfectly succeeded to save energy, materials, recovered scrap and so on. You in US are not only capable to do so but you will perform this when costs will arise. As an ordinary western european I do not feel bad with our local european no-waste pressure: When I live in US for some weeks, living like americans, I do not feel better because I waste far more energy and materials per day as before.
Your economic optimization will simply change towards more efficient tools and ways of life just because of economical pressure. This occurred in Europe because governments imposed this for decades via taxes.
LFReactors, whatever thermal of fast neutron, would anyway face same post-reaction radioactive power decay from fuels.
By th way, all our LWR have the same common weakness, put in evidence during RBMK Tchernobyl accident: Whenever core control is fully lost, only chemical forces govern situation development.
With its 1,700 tons of graphite, this reactor had a built-in reserve of chemical energy about 5 times greater than the overall fuel heat decay (integraed over several months). This is why about 70% of radioactive core content have been dispersed by graphite burning in air.
Now let us look at the two light water reactor accidents, Harrisburg and Fukushima: No graphite, just about 25 tons of zirconium; When burning in steam, there is no further gas volume delivered, just heat therefore there were no significant energy and gas reserves to provide the momentum dispersing more than 6% of cores radioactive content. The best for region's population!
But the story is not closed: zirconium generated hydrogen, equivalent to max 13,000m3, cannot be condensed and HAS to excape, not by breaking a pipe but convincing plant operators to open valves and self-break the second confinement barrier integrity, ie reactor vessel. Thence unlike lucky Harrisburg it has also to escape thru same "convincing power" to break the last barrier integrity and goes in Nature. Subsequent external explosions are of no matter.
So, all our LWR suffer from the same design flaw: they house their own vicious self-destruct power, zirconium.
Imaging a minute, just theoretically, that fuel cladding be made of platinum or af any good-will metal unable to react with water steam whatever temperature is? Fukushima BWR would have been also deprived of water cooling, rods would have fused, temperature would have been rising out of control excepts that external water showering would have been able remove heat without hydrogen pressure: Nett result is that NO contaminated steam would have been released.
Back to our LFReactors: I rise two questions:
1- I am unsafe with graphite moderator inside. Better use really inert moderators even if less performant: magnesium oxyde, ceramic or… none as it has been demonstrated in CEA,
2- Fluoride phase permanent cleaning & processing allows to split fission products, recycle active materials but do not change the global "fuel heat decay" problem, it just splits it into several different parties. Therefore which are the devised processes destinated to cool, store and isolate from outside these very powerful heat generator ? Rather to re-invent a (square!) wheel, I wish someone to explain us, thanks,
Herve Duperray
Dear Kirk,
I have seen some of your videos which are very interesting (i would even say revolutionary)and I have been shocked. It reminds me to the story of FM radio broadcasting versus AM broadcasting in the 30's (which of course was times less important than this issue, but the analogy may be useful).
I am an economist from Spain so I am not a technician on this matter. As far as I can understand one of the main problems here is the reactor piping that has to deal with high temperature molten salts. From my view oxigen from atmosphere is a real fear as it can rapidly oxidize high temperature metal piping. Perhaps xenon is a solution to this as it could remove oxigen from atmosphere in the containment. This reactor should be safer in a xenon containment atmosphere. Additionally xenon seems to be a powerful neutron absorber. It could also isolate hot graphite from oxigen in an emergency situation.
Another drawback may be dealing with a kind of "refining" factory needed to separate/add different elements from/to the salts. As it is widely known refining is an industry where accidents may take place. Human or technical errors are often made and the results are explotions and/or leakages. For example an error dealing with hidrogen or fluorine involve chemical risks in the non nuclear part of the reactor. I can imagine these problems are real chalenges.
Thanks a lot for spreading this knowledge.
Benjamin Serrano.
I do not understand how the Bible does not support responsible, environmentalist behaviour on Spaceship Earth. As one who loves this world and my family – I am a Companion of the Society of St Francis and an environmentalist – I am comforted in the knowledge we may still live quite well without continuing to render our planet uninhabitable by humans. The hard part is going to be getting it all up and running.
==> DOE seems to have become enthusiastic about Small Modular Reactors (SMRs). Here's the very best SMR design: Thorium-Fuel Molten Salt Reactors (TFMSRs), aka LFTRS. A functinal prototype LFTR will be built by Flibe Energy, founded by thorium nuclrear engineer, Kirk Sorensen, with a goal of 1 Jun 2015 for criticality, 50th anniversary of the first Oak Ridge MSR.
Everyone should be aware that as of 25 Jan 2011 the Chinese Academy of Science (CAS) announced a development program for Thorium-Fuel Molten Salt Reactors (TFMSRs). Reps from the CAS visited Oak Ridge Labs last Fall (2010) to make a reality check, and have now decided to eat our collective lunch by going after the IP and patent rights to molten salt reactors. This is a true "Sputnik Moment" for U.S. energy development.
The rest of the world can go their merry way, boiling water, risking explosions, and straining to create reactor designs using solid-fuel uranium or thorium. Flibe Energy […] http://flibe-energy.com/ […] will create a better way to "burn" all the HEU, spent fuel rods, Pu239, and 99% of the TFMSR fuel, while reducing the nuclear waste storage/disposal problems by a factor of 1,000, and max storage time to 300 years. Think U.S. factories manufacturing small (100MWe), modular, standardized TFMSRs for clean nuclear energy. Think jobs!
LTFR don't need moderators including graphite one- the reaction is essentially self controlling due to expansion of the salts. Graphite wouldn't last very long in a fluorine environment as they reprocess the liquid salts using fluorine- carbon tetrafluoride is a gas under these conditions. Only Xe135 is a significant Neutron barrier and that's not the common isotopes of naturally occurring xenon so its no good as a neutron barrier. There is a real deficiency of proposed materials information- only suggested is Hastelloy N, Haynes 242 and a few other Nickel-Molydenum alloys. There is a real shortage of material choices- including ceramics.
Congratulations for bringing out wonderful concept where whole fuel cycle is made so compact, reducing not only seccondary waste generation levels significantly but long half life fp wastes as well.Eliminating prolong cooling and containment requirements seems good however, I am not sure hazards related with Graphite moderator, need to maintain homogeniety of liquid fuel in the solvent all the time to avoid unwarrented criticality hazards and U232 generated hard gamma shielding requirements can be dealt with.
I think it is our responsibility to educate the public about the benefits and safety of LFTR technology. It can be key to energy independence for America. This would be a tremendous benefit to the economy, as the trade deficit, exacerbated by the highs cost of imported oil, could transform to a trade surplus, as the weak dollar increases exports. We need to educate the public and to make elected officials aware that a solution to economic malaise is LFTR technology.
P.S. This is my third attempt to get past the CAPTCHA filter.
I wonder if a LFTR coupled with hydrogen production on a site near an old coal mine (perhaps replacing a coal fired plant) could be used to power a Bergius process. http://en.wikipedia.org/wiki/Bergius_process
Yes there would be CO2 emissions when the fuel was burned but a significant fraction of the fuel value of the resulting liquid fuel would come from the reactor.
What if a similar process could be developed using bio-mass as a carbon source?
Also,I know that oilsands in Alberta (where I live) are not particularly popular right now, especially with all the natural gas that needs to be burned for process steam and upgrading. Again, LFTRs coupled with hydrogen production could provide the hydrogen needed to turn heavy and/or partially oxygenated hydrocarbons into valuable liquid fuels. Not to mention the immense process heat needed for de-sulphuring/de-oxygenation, coking, cracking, etc.
Again a fraction of the heating value of that fuel would be carbon neutral. So it would be of similar carbon-reducing value as current efforts to blend ethanol into gasoline or bio diesel into diesel.
Radioactive Xenon produced in nuclear reactions decays into Caesium, not a stable isotope of Xenon. I supposed you could add an additional "blanket" layer to the reactor to expose the Xenon to neutron bombardment, that would produce stable Xenon, though it would also take neutrons away from the reaction (the whole point of removing the Xenon from the salt in the first place). Neodymium harvesting seems fairly sound (most produced isotopes are stable to begin with), as does the use of any radioactive byproducts, but not Xenon.
Other than that, very nice article. This technology is of great interest to me, and I would very much like to see it utilized.
When can I get a 25KW LFTR for my backyard? If I charge the electric power company for my unused power, how soon would I break even on my investment?
very encouraging research. Good luck with further writings! Too bad we wasted so much cash on nuclear fusion when thorium is such a cheap and abundant fuel.
What is the cost of isotopic seperation of Lithium?
Thanks for such insight and clarity regarding this technology. As an adjunct instructor of Physics I try to encourage my students to be open minded about nuclear power.
It is unfortunate that the media is so biased against nuclear power that the average citizen is afraid of this technology.
Our leaders lack the courage to educate the herd and move forward with technologies that can assure our energy independence. I continue to promote your writings and send letters to my government representatives.
My longstanding objection to nuclear power has always been its inherent danger, not least in the reprocessing or storage of radioactive waste. My daughter alerted me to the possibilities of Thorium by sending me a link to a recent article in The Daily Telegraph, the UK newspaper. It was the first I'd ever heard of this type of reactor, and I can see how important a development this would be. I shall be writing to members of our government to suggest that as we are about to commission new nuclear reactors, this is the way to go. I shall also be writing this month's blog (View From Trevadlock Cross) on the subject, though I don't think many people read it!
I think, though, that if you could come up with a really simple explanation that a baby could understand, it would be helpful in getting the message across.
Japan (FUJI) and China both appear to be pursuing LFTR reactors
This sounds like a great idea that solves some of the problems with the current light water technology. However, the devil is in the details, and this idea creates some new problems. For instance, non-recyclable fission products, with high dose rate and long half lives will be created. This material will need to be solidified and stored (where?) using remote handling, shielding, and licensed shipping container.
Injection rate of U233 into the reactor can affect the reaction rate. It needs to be proven that this can be controlled.
Old problems remain, such as the removal of decay heat under all conditions including 9.0 earthquakes and tsunami.
It is important to prove the concept in a methodical way. We need a small, relatively inexpensive, short project(s), find out what the problems and solutions are, and then build from there. Keep it simple using proven technology where ever possible.
I agree with the idea of the retro-fitting of the existing coal-fired powerplants and converting them over to this technology. But, get ready for the fight from to coal industry, as well as the existing nuclear power industries–both generation and support–because you are basically phasing out an antiquated and danger riddled technology (look at the recent reactor disasters in Japan) This alone should be the driving force to move into the 21st century with our nuclear power, as well. I agree with Rod Clemenson–FOR ONCE, LETS BE THE FIRST WITH THE BEST!!!!!
Kirk and All
I first caught Kirk Sorensen on Dr. Kiki Science Hour on the Twit Network http://twit.tv. I've completely read read thru this site less some of the ORNL Documents as well as Barton's Nuclear Green Revolution site. I live in West Virginia now so LFTR would surely go over like a Lead Balloon in this Coal Producing State. I am a Navy Veteran who has served on a Nuclear Aircraft Carrier so I'm comfortable LIVING ON A NUKE!!
To address this thread I'm afraid the AEC/ERDA is not the answer especially as Industry/Government will attempt to introduce the Next Generation of Reactors. They will just botch it. Everyday I'm becoming a little more Libertarian, but I haven't drunk all that Cool Aide yet. Kirk's Market Place orientation is a great solution. Since GE and Westinghouse like the Razor / RazorBlade analogy to market and sell their Reactor/Refueling concept they're not in the LFTR game. It would be to their to their benefit to get behind this as Plutonium Breeding is a Multi-Human Generational process time wise and just plain too expensive. If the Westinghouse / GE Mathematical Strategic Business Forecasters plugged into the Sorensen vision they would make a lot more money. Capitalism is a Entrepreneurial process, it punishes the poor Entrepreneurs by failure and rewards the ones who forecast better the use of Capital and the Means of Production. It may very well be a case of Creative Destruction. These companies are just to deep into PWRs. The present/future companies will take on LFTR's for profit. If we go back to the Original Wigner/Weinberg we will see LFTRs as a Chemical Engineering/Company opportunity. (Kirk kudos to you for talking to anyone and everyone about this, so forgive me if I am stating any lobbying you've already done but haven't share with us). I'm talking about Union Carbide, Monsanto and Petroleum Refiners and all their associated Trade Associations. Just the extraction of Fluorine from stockpiles of Uranium Hexafluoride would be a dream business from all the above. Next Potential Brayton Cycle Turbine Manufacturers. Honeywell, Rolls Royce, Pratt & Whitney and Williams. If General Electric/SNECMA Jet Engine group is semi independent to pursue Brayton Cycle Engines they would be wise to jump onto this as well. GE is well known for their Natural Gas Compressor/Turbines to pump Natural Gas. Waste Management to transport the Stockpiles of Nuclear Wastes to Processors. Airplane Manufacturers and their suppliers are Ideal to Build LFTRs as well as General Motors Electro Motive Division, their Locomotive Building Division. Governor Elect Rick Snyder of Michigan an executive from Gateway Computers is open for business(High Tech Guy too). Greens such as Amory Lovins of the Rocky Mountain Institute should love this pitch. Kirk I do know you're not a fan of his. But Lovin's does have a concept of Small is Beautiful in Electric Power Generation. Small efficient generators mass produced for economic reduction of costs and placing them close to their Loads to reduce transition losses and bypass the building of more Transmission Lines. His misguided hate of Nuclear can probably turned around with your LFTR vision. Give Lovin's his due, he's one heck of a Promoter. If the Quads of World Energy Needs, Losses and Efficiency are brought to bare along with the Processing of Nuclear Wastes for LFTR fueling, safe sequestration I'm sure even he will get on board. If we revisit General Electric along with the United States Navy, just think about this. Propulsion Systems on Almost all Large Cruisers Ticonderoga Class, Destroyers Kidd Class,Destroyers Spruance Class are General Electric Gas Turbine with General Electric Reduction Gear Sets to turn the Propellers. Imagine all the JetFuel these ships burn and they burn a lot!!! It's certainly a lot more expensive now. LFTRs on these vessels would revolutionize the Fleet. Kirk in Ship Yards they use torches to open these ships all the time to take Big Things Out and put Big Things in. LFTR anyone!!! Hello GE….. When I was on the USS Nimitz CVN 68 we use to serve JP-7 to some of our gas turbine Destroyer Escorts all the time during underway replenishment, even the steam powered ships. In 1980 when Russian Gas Turbine Combatant Ships were following us around the Indian Ocean our Nuclear Powered Battle Group Rang Up 30 plus knots. Gas Turbine ships can go fast but not far and fast. We ran for 12 plus hour and we ran them out of gas then walked away. Now how's that for fuel/power density! The Nimitz Class has two 500 Megawatt Thermal Output Reactors. The Carrier Enterprise had a Thermal Output of 1.2 Gigawatts using 8 smaller submarine reactors about 140 Megawatts Thermal apiece. Kinda of like a Sorensen mini park of Electric Power LFTRs. A LFTR initial Fissile load would be an improvement by at least 35 times on the Uranium 235 alone not to mention all that Uranium 238 we lugged aroud, the Oxide, the Pressure Vessel that a PWR Nuke has. So the GE business for LFTR Naval Propulsion is compelling, or a GE Competitor. My last point of Naval History. In the 1930's General Motors Bid at a loss to develop and produce Diesel Engines for the United States Navy to put into Fleet Boat Submarines. GM was smart, these same diesels also were perfectly sized to go into the bread and butter business of Diesel Engines for Diesel/Electric Trains. Sooooo…. two-to-three 100 megawatt electric LFTRs retrofitted to a Gas Turbine Cruiser/Destroyer. Fulfill the Naval Propulsion contract. Assembly line the LFTRs for Power Generation.
Thanks Mr. Shapiro! LFTR application to naval propulsion has long been an interest of mine and I think it is a compelling application.
I failed to see any discussion of reducing our energy requirements through conservation. If the US reduced its energy use to that of Europe, the whole nuclear industry could be shut down tomorrow. However, that is just dreaming; Americans will not voluntarily reduce their energy consumption. "The American way of life is non negotiable" has been the mantra of those who wish to maintain the situation where about 5% of the world population uses 24% of the worlds resources. I am not suggesting that the US reduce its standard of living to that of the Third World, but some perspective is in order. However, I do think that Thorium fueled reactors offer advantages and that they need to be considered.
Rob carroll, while i agree with you that conservation is crucial, I disagree with your statement 'the whole nuclear industry could be shut down tomorrow'. United states energy conservation isnt on trial here; viable energy production is.
Dear Kirk,
I am really amazed about this technology. I discovered it almost 3 years ago and I only want to say, keep up the good work. Will try to get the technology known to friends, neighbours politicians as well.
Greetings from Europe, Brussels.
Roeland
The "american way of life is not negotiable" is for me a political dud. By 1942 your grand-grand parents perfectly succeeded to save energy, materials, recovered scrap and so on. You in US are not only capable to do so but you will perform this when costs will arise. As an ordinary western european I do not feel bad with our local european no-waste pressure: When I live in US for some weeks, living like americans, I do not feel better because I waste far more energy and materials per day as before.
Your economic optimization will simply change towards more efficient tools and ways of life just because of economical pressure. This occurred in Europe because governments imposed this for decades via taxes.
LFReactors, whatever thermal of fast neutron, would anyway face same post-reaction radioactive power decay from fuels.
By th way, all our LWR have the same common weakness, put in evidence during RBMK Tchernobyl accident: Whenever core control is fully lost, only chemical forces govern situation development.
With its 1,700 tons of graphite, this reactor had a built-in reserve of chemical energy about 5 times greater than the overall fuel heat decay (integraed over several months). This is why about 70% of radioactive core content have been dispersed by graphite burning in air.
Now let us look at the two light water reactor accidents, Harrisburg and Fukushima: No graphite, just about 25 tons of zirconium; When burning in steam, there is no further gas volume delivered, just heat therefore there were no significant energy and gas reserves to provide the momentum dispersing more than 6% of cores radioactive content. The best for region's population!
But the story is not closed: zirconium generated hydrogen, equivalent to max 13,000m3, cannot be condensed and HAS to excape, not by breaking a pipe but convincing plant operators to open valves and self-break the second confinement barrier integrity, ie reactor vessel. Thence unlike lucky Harrisburg it has also to escape thru same "convincing power" to break the last barrier integrity and goes in Nature. Subsequent external explosions are of no matter.
So, all our LWR suffer from the same design flaw: they house their own vicious self-destruct power, zirconium.
Imaging a minute, just theoretically, that fuel cladding be made of platinum or af any good-will metal unable to react with water steam whatever temperature is? Fukushima BWR would have been also deprived of water cooling, rods would have fused, temperature would have been rising out of control excepts that external water showering would have been able remove heat without hydrogen pressure: Nett result is that NO contaminated steam would have been released.
Back to our LFReactors: I rise two questions:
1- I am unsafe with graphite moderator inside. Better use really inert moderators even if less performant: magnesium oxyde, ceramic or… none as it has been demonstrated in CEA,
2- Fluoride phase permanent cleaning & processing allows to split fission products, recycle active materials but do not change the global "fuel heat decay" problem, it just splits it into several different parties. Therefore which are the devised processes destinated to cool, store and isolate from outside these very powerful heat generator ? Rather to re-invent a (square!) wheel, I wish someone to explain us, thanks,
Herve Duperray
Dear Kirk,
I have seen some of your videos which are very interesting (i would even say revolutionary)and I have been shocked. It reminds me to the story of FM radio broadcasting versus AM broadcasting in the 30's (which of course was times less important than this issue, but the analogy may be useful).
I am an economist from Spain so I am not a technician on this matter. As far as I can understand one of the main problems here is the reactor piping that has to deal with high temperature molten salts. From my view oxigen from atmosphere is a real fear as it can rapidly oxidize high temperature metal piping. Perhaps xenon is a solution to this as it could remove oxigen from atmosphere in the containment. This reactor should be safer in a xenon containment atmosphere. Additionally xenon seems to be a powerful neutron absorber. It could also isolate hot graphite from oxigen in an emergency situation.
Another drawback may be dealing with a kind of "refining" factory needed to separate/add different elements from/to the salts. As it is widely known refining is an industry where accidents may take place. Human or technical errors are often made and the results are explotions and/or leakages. For example an error dealing with hidrogen or fluorine involve chemical risks in the non nuclear part of the reactor. I can imagine these problems are real chalenges.
Thanks a lot for spreading this knowledge.
Benjamin Serrano.
I do not understand how the Bible does not support responsible, environmentalist behaviour on Spaceship Earth. As one who loves this world and my family – I am a Companion of the Society of St Francis and an environmentalist – I am comforted in the knowledge we may still live quite well without continuing to render our planet uninhabitable by humans. The hard part is going to be getting it all up and running.
Thanks so much for doing all you have done.
Michael Burns
==> DOE seems to have become enthusiastic about Small Modular Reactors (SMRs). Here's the very best SMR design: Thorium-Fuel Molten Salt Reactors (TFMSRs), aka LFTRS. A functinal prototype LFTR will be built by Flibe Energy, founded by thorium nuclrear engineer, Kirk Sorensen, with a goal of 1 Jun 2015 for criticality, 50th anniversary of the first Oak Ridge MSR.
Everyone should be aware that as of 25 Jan 2011 the Chinese Academy of Science (CAS) announced a development program for Thorium-Fuel Molten Salt Reactors (TFMSRs). Reps from the CAS visited Oak Ridge Labs last Fall (2010) to make a reality check, and have now decided to eat our collective lunch by going after the IP and patent rights to molten salt reactors. This is a true "Sputnik Moment" for U.S. energy development.
The rest of the world can go their merry way, boiling water, risking explosions, and straining to create reactor designs using solid-fuel uranium or thorium. Flibe Energy […] http://flibe-energy.com/ […] will create a better way to "burn" all the HEU, spent fuel rods, Pu239, and 99% of the TFMSR fuel, while reducing the nuclear waste storage/disposal problems by a factor of 1,000, and max storage time to 300 years. Think U.S. factories manufacturing small (100MWe), modular, standardized TFMSRs for clean nuclear energy. Think jobs!
LTFR don't need moderators including graphite one- the reaction is essentially self controlling due to expansion of the salts. Graphite wouldn't last very long in a fluorine environment as they reprocess the liquid salts using fluorine- carbon tetrafluoride is a gas under these conditions. Only Xe135 is a significant Neutron barrier and that's not the common isotopes of naturally occurring xenon so its no good as a neutron barrier. There is a real deficiency of proposed materials information- only suggested is Hastelloy N, Haynes 242 and a few other Nickel-Molydenum alloys. There is a real shortage of material choices- including ceramics.
Congratulations for bringing out wonderful concept where whole fuel cycle is made so compact, reducing not only seccondary waste generation levels significantly but long half life fp wastes as well.Eliminating prolong cooling and containment requirements seems good however, I am not sure hazards related with Graphite moderator, need to maintain homogeniety of liquid fuel in the solvent all the time to avoid unwarrented criticality hazards and U232 generated hard gamma shielding requirements can be dealt with.
I think it is our responsibility to educate the public about the benefits and safety of LFTR technology. It can be key to energy independence for America. This would be a tremendous benefit to the economy, as the trade deficit, exacerbated by the highs cost of imported oil, could transform to a trade surplus, as the weak dollar increases exports. We need to educate the public and to make elected officials aware that a solution to economic malaise is LFTR technology.
P.S. This is my third attempt to get past the CAPTCHA filter.
Hello,
Im in St.Pauls high school and i wanted to ask if i can use this image from your site. https://energyfromthorium.com/essay3rs/
I wonder if a LFTR coupled with hydrogen production on a site near an old coal mine (perhaps replacing a coal fired plant) could be used to power a Bergius process.
http://en.wikipedia.org/wiki/Bergius_process
Yes there would be CO2 emissions when the fuel was burned but a significant fraction of the fuel value of the resulting liquid fuel would come from the reactor.
What if a similar process could be developed using bio-mass as a carbon source?
Also,I know that oilsands in Alberta (where I live) are not particularly popular right now, especially with all the natural gas that needs to be burned for process steam and upgrading. Again, LFTRs coupled with hydrogen production could provide the hydrogen needed to turn heavy and/or partially oxygenated hydrocarbons into valuable liquid fuels. Not to mention the immense process heat needed for de-sulphuring/de-oxygenation, coking, cracking, etc.
Again a fraction of the heating value of that fuel would be carbon neutral. So it would be of similar carbon-reducing value as current efforts to blend ethanol into gasoline or bio diesel into diesel.
Radioactive Xenon produced in nuclear reactions decays into Caesium, not a stable isotope of Xenon. I supposed you could add an additional "blanket" layer to the reactor to expose the Xenon to neutron bombardment, that would produce stable Xenon, though it would also take neutrons away from the reaction (the whole point of removing the Xenon from the salt in the first place). Neodymium harvesting seems fairly sound (most produced isotopes are stable to begin with), as does the use of any radioactive byproducts, but not Xenon.
Other than that, very nice article. This technology is of great interest to me, and I would very much like to see it utilized.