The Liquid Fluoride Thorium Reactor: What Fusion Wanted To Be

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Steps to prevent a meltdown in a fusion reactor:

  1. Turn it off

  2. There is no 2, it's off. The magnetic fields needed to contain the molecules so they could fuse are down and now they spread out and stop fusing.

  3. Damnit, there's no 3 either. The thing is powered down. The high temperatures are no longer quite so high and getting less high all the time.

Steps to reduce waste products from a fusion reactor:

  1. Oh come on, is helium really so common that it's trash now?

  2. Oh fine then, just vent it into the atmosphere, it will quickly find its way to the top (because it is light and unreactive) and disappear into space.

Steps to prevent weapons-grade byproducts in a fusion reactor:

  1. Stop setting off a supernova in the reaction chamber. Fusion of heavy elements like U-235 require vastly more energy than you get back. And supernovas usually have a very negative effect on the solar system they occur in.

  2. If you've made it this far, good. You didn't set off a supernova in your reaction chamber.

👍︎︎ 57 👤︎︎ u/Wavicle 📅︎︎ Dec 29 2008 🗫︎ replies

This technology is very promising. It has an essentially proven, working-today technology, physically proved safety, and essentially unlimited fuel supply. Nuclear waste is much less (orders of magnitude) than any current fission plant could offer.

The main point is cost - the same point fusion, assuming it will ever appear as a power source, will have to convince at. In contrast to fusion, I am somewhat confident they will not overrun their initial estimates by more than a factor of three.

👍︎︎ 8 👤︎︎ u/kolm 📅︎︎ Dec 29 2008 🗫︎ replies

Thorium? I used to mine that shit in warcraft

👍︎︎ 23 👤︎︎ u/runrunwootwoot 📅︎︎ Dec 29 2008 🗫︎ replies

Here's his original PPT talk. PDF would be better, of course. I think video is an annoying, low-bandwidth way of transmitting info, unless you actually need a moving picture show.

👍︎︎ 8 👤︎︎ u/anonymous-coward 📅︎︎ Dec 29 2008 🗫︎ replies

Behold the power of Thor! ... ium.

👍︎︎ 3 👤︎︎ u/Codebender 📅︎︎ Dec 30 2008 🗫︎ replies

I'm sold - this is better fission, let's ramp it up.

👍︎︎ 2 👤︎︎ u/cyantist 📅︎︎ Dec 29 2008 🗫︎ replies

As soon as the equilibrium between fuel and pressure/temperature is broken the reaction self terminates. Its too precise to get out of hand, b/c as soon as it does it ends.

👍︎︎ 2 👤︎︎ u/BlazinEurasian 📅︎︎ Dec 30 2008 🗫︎ replies

Thorium Oakenshield !?

👍︎︎ 2 👤︎︎ u/Ferrofluid 📅︎︎ Dec 30 2008 🗫︎ replies

Shouldn't that be "Fission"?

👍︎︎ 2 👤︎︎ u/ortsed 📅︎︎ Dec 29 2008 🗫︎ replies
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>> Welcome everybody. I'm going to be--try to be short because we're running a little bit late and then there is a talk after us. So, today we're going to have a talk about, I don't know, alternative energy. I think it's important. I think if we really want to make a denting CO2, we need to be looking at some serious stuff as well. And for this purpose, we have today Dr. Joe Bonometti and he is a NASA Chair Professorship--he had a NASA Chair Professorship position at the Naval Post graduate School. He worked at NASA for 10 years as a technology manager, lead systems engineer, nuclear specialist and propulsion researcher. He's basically a rocket sciences guy. He--their manage--manage the Emerging Propulsion Technology Area for in-space systems, the Marshall Aero launch team, as well as a variety of auto power and propulsion assignments. After rendering a doctorate degree in mechanical engineering from University Of Alabama in Huntsville, he spent several years as a research scientist and senior research engineer at the UAH Propulsion Result--Research Center, where he served as a principal investigator and manager for the Solar Thermal Laboratory. He has worked as a senior mechanical designer at Pratt & Whitney supporting aircraft engine manufacturing at--and at the Lawrence Livermore National Laboratory within the Laser Fusion program. He's a graduate from the United States Military Academy. I think you'll find out that he knows what he is talking about and I am eager to hear what he has to say. So, please give him a warm welcome. Thank you. >> BONOMETTI: Thank you. That was a great introduction. It's a blessing to be here. I have a lot of material to go over so I'm going to suspend some of my normal comments and jokes and go right to it. I planned to be talking about this in context of fusion but I'm going to hold back some comments for there to get through the material and get to the questions. One note in the beginning, I come here as an individual. I don't represent any agency or organization. There's a loose fitting group of people around the country mainly specialist, technologist. They're interested in this field; both in energy and in particular thorium and that we all have day jobs, fortunately good paying day jobs for the most part. And so, we come to give this information out freely and examine this idea and the use of thorium as an energy source. Outline; I'm just going to mention that I talk about systems engineering because I've taught that as well as my thermodynamics and nuclear background. You only see a little bit there of that. Some assumptions; I'm assuming that most people understand the energy crisis. It's global in nature, it's--nobody's got a quick fix, at least nobody would agree what the quick fix is. Thorium is not going to be commonly known especially as an energy source. Increased electrical capacity is very important to the overall energy consumption. And the last thing is, energy equates the state or the standard of living and one of the last green energy forums I was at listening to, they equated 258 slaves if you will working full time and hard labor, 365 days a year for each person in the United States. You can see that that level of energy is what gives us a standard of living. This slide comes from Lawrence Livemore Laboratories. It's one that I would spend a long time on. I think it has a lot of great points to be made. I just say that if you don't know what quad is 10th of the 9th, BTUs. It's a lot of blot of energy and if you just take all the energy we have in the United States and break it up into 100, you get 100%. So you can see, oil is around 40% and that line is the thickness--equivalent to that. You can see that most people would say we want to increase these desirables, okay. And notice that the desirables are pretty thin and it's kind of hard to increase them. These are the ones we would probably want to phase out more as well as less oil. We have huge energy losses and electricity production, about 25% efficient overall. Conservation is great, we do it at home. Mostly engineers, if they don't have to create any entropy increase percent in the universe; they would like to minimize that. But at the same token, you can see that we've paid the price up here. And that conservation as much as we want to, there's not a whole lot of gains there, in these two areas. The other thing is, if you notice right here, you can't make that line go to zero. Thermodynamics says you always have to have a cold sink. You always have to move energy. One example I talk about is wind; that you can put up a windmill and you can put another windmill behind it and you're going to extract a little more energy and slow that air down but there's a fundamental limit. If you put too many of them in there, you'll not only get the last one to not move because there's no air flow, okay, you've actually affected all the windmills in front of it, until you get no energy. So, there's a fundamental limits to thermodynamics. You always have to have some lost there. And of course, most people would consider that you want to increase the electricity flow into cars or transportation areas as well. So, what you really want to do is, if you can't roll these things fast enough on the order of this size, you really want some new energy source, something big, something, you know, it comes in, it can be readily built and provide that very big, wide line. Something like fusion, right? Everybody would like to see that. Well, I'm here to talk about thorium and whether thorium can be that line. And also, what's the best way to extract that energy? Now, we're now getting to--go out of details, you can take a little bit of thorium, put it in a normal reactor and you get some benefits out of it, okay. But it's not an end-all and it doesn't extract all the energy out of that thorium that you'd like to and it doesn't mitigate all the problems you have with today's nuclear power. Thorium; just for background, is an element. 1828, it was discovered. It is slightly radioactive. It got a very long half-life, that's why it's around and it provides real background radiation along with uranium, most of it comes from that. Just a little bit of thorium that's always around in the soil and in rocks and minerals. The only thing I'm going to say here is that thorium is not really commercially used for anything of much these days. It is a metal. It's got a very wide liquid range, some other interesting properties. I'm not going to go into any other details to know that--commercially, it's not a big deal. Now, this is a log scale of what's available in the Earth's crust and you see that the beginning, you have oxygen, silicone, aluminum. Down here, at a 100 parts per million, in this box here, you have copper in the middle and at--towards the bottom, you got lead and thorium. And you can see I expanded this little area out. Uranium is about four times less than thorium. Boron, which some talks have a--even at Google, we've talked about fusion using boron, all right. It's there. It's readily available but what's interesting is the uranium that you're really interested, the one fissile material, it actually split, is way down here, orders of magnitude less. So, thorium, on theory--theoretical basis; the United States has about 20 % of the world's reserves. To put this in perspective, one would say, if you replaced all the energy--electrical energy generation in the United States that you saw before and I'm not suggesting we do that. A lot of other energy sources will play but that's about 400 metric tons. One mine can produce about 40--500 metric tons per year, you can see that's 10 times the amount. The United States has actually--the government has buried a bunch of thorium. They didn't know what to do with it. After paying for it and storing it, they just put it in the ground literally in these casts. And you can imagine that's--even at this--huge amount energy usage that last 8 to 10 years. In a practical sense, this would last us probably 25 to 50 years. And you've certainly have plenty of thorium available around the world. That's not enough. Like fusion, we can go to moon. The difference is there, we don't have to mine the entire surface looking for it. Thorium gives a nice signal and you can detect that from space and so we can map it and where the hotspots are, you know that there's a pretty good thorium deposit there, same with Mars. So, we know that it's out there and the asteroids, thousands of years worth of power. Now, because of my systems engineering background, a little bit of the flavor I'm going to give you is in the vain of how do you select things or systems engineering criteria. And this comes from the aerospace that about 80% of a projects life cost and benefits are going to be locked in the first initial decisions you make. And that pretty much for all technologies especially hi-tech technologies; that holds pretty well true, 70%-90%, somewhere in there. And the reason is that it sets your theoretical limits, it also--at the time, you have your least real world knowledge of how you're going to build or how you're going to go about doing this project. So you--the thing I try to teach is you look for the inherent balances, something untouchable, at least--reasonably untouchable and a growth factor that your concept will gain and exceed what your goals are. So let's take nuclear technology that we see today. You know list the pros and cons that are shown here. Most people recently have looked at, you know, no green house emissions and that's because in this case, about 3rd comes from electricity and before majority of that is coal. Nuclear doesn't have that. Now, to be very honest, one would have--and analyze, well, how much resources does all this make when I go to build a plant and how much CO2 do I produce? In the case of a nuclear energy, there is some but over the lifetime and the amount of energy a nuclear plant produces, this is probably--pretty a fair game to say it produces no CO2, but it's something you need to be honest about and compare. What if you can take some of the cons out of there, the safety fears and long term sustainability and terrorist or proliferation issues and make them go away or at least minimize them. It sounds like what fusion wants. Another thing on systems engineering is the concept of power density and efficiency. I can't go through all these but obviously land usage, you know, the maintenance cost, anything that you have to deal with, the overall cost of a lifetime a project--smaller is not just convenient. It drives--90% of the time, it drives the cost and therefore--at least, the social cost, maybe not in a particular market but across the board, it usually does. And you'll see that that's very important for power density and efficiency. And example that comes into mind is the cost material labor and then the distance from the end user, and all these other factors that factor in. I'm not going to go into a big detail. This is, you know, information that's available and have been readily been talked about. Natural gas turbine engines is about one-tenth the amount of steel for example in a nuclear plant and a nuclear plant is actually pretty good compared to some of the others. But you see that in recent years, what are we building? We're building these very expensive, difficult gas using machines that are very hi-tech, yet we're building more of those. Why? Well, because overall, the resources necessary to produce that and to meet the demand now makes you go for these things. And that's what--that what's been happening. So, in the light of the--what fusion wanted to be; safe, proliferation resist, et cetera. That was one of the jokes. Today, we have basically large plants although there were a couple of Google talks that's talking about making fusion in a way that's smaller. I would love that to happen but basically, we've got these very large plants and of course they use a lot of it--they produce a lot of energy but they also absorb a lot of energy in producing the energy. So your net gain is not as good as you would want. Kind of get into the history as well as the physics at the same time and talk you through a little bit about thorium and why we ended up with a--the LFTR concept. Three basic nuclear fuels everybody should know, you know, uranium-235 is what's naturally found, that's what we can start with. These two have to come from fertile material, we have to make them, they aren't found in nature. And in history, everybody was working on weapons and so you have an enrichment facility, you need a weapon designed, you need fabrication techniques. For the uranium-238, you need a neutron source which also usually starts with the uranium-235. You chemical separate, you need a new weapon design, new fabricating techniques, you get a slightly better bomb, so I'll say on that. And thorium, well, they discovered, you need the same thing you need with the uranium-238, chemical separation, but then there's some contaminant in this usually and which should go to an enrichment facility but it's a hot enrichment facility. You need yet a new weapon design, a new fabrication techniques to get the same kind of bomb. Well, obviously, these two are what the world has shows in the --to work on. Well, at the same time, most of the people that worked on those projects also were good people trying to say, "What good can we do besides weapons?" An electricity production was one of them early on and they had the same problem. They had the same materials to start with. You need enrichment or heavy water production, a new--a fuel design, okay. A little bit different--but it's still solid fuel, fabrication and then electrical power. I say short-term electrical power because at the time, they really underestimated how much uranium-235 was in the world. It was a little bit more than they actually are accounting for originally. But at world usage at the U.S. levels, it's still a very true statement to say, you know, there will be peak uranium if you--if you base everything on uranium-235. Well, you can go with breeders; fast spectrum breeder reactor, you need some sophisticated controls. We'll talk about that in little bit more. Some fuel design and you get electrical power but you also get a whole lot more production of plutonium which has been used for nuclear power and run other reactors produce electricity or of course, you can use that for weapons. Thorium, on the other hand looks a little different at each time. Thermal spectrum, chemical processing and you get electrical power, it's very hard to get any extra out of it and I'll explain that here. Enrico Fermi argued for the plutonium-based economy essentially. And one of the reasons, you get three neutrons on average per fission and the real key number you want to look at is this blue line and that is the number of neutrons that come for absorption and you need at least two. You need one to spilt, and one to breed your next fuel. And so, in reality, you need a little bit more than that because losses through the reactor, you got to make it reasonable. So you have to work this thing, it doesn't work here at all in thermal spectrum, you have to work up here in the--near the--what I would call the bomb spectrum, okay. You're using now the fast neutrons coming off the reactor from the fission. You're not slowing them down in a thermal--in a thermal sense. And you can see that this number really climbs very good, which means you get a whole lot more than two, which means you get production of plutonium or you can use it for production of plutonium. Well, Eugene Wigner at the time argued, "Well, you know, it's great for weapons but we really want to base our economy on thorium." It's more available and more important. It runs on a neutron spectrum--a thermal spectrum such that it's a lot safer, a lot easier to control and you can, you know, use these reactors. It is--this is a very difficult reactor, very touchy reactor to work. But of course, it doesn't produce much because you see the average from the fission is only two and a half and the actual absorption averages a little bit below that, okay. So you're above two which is enough, but with real, real losses, you're not going to breed a whole lot of extra material out of this--out of this system. Well, historically, what did we do? We went from weapons to--they're not on the list. There is Eisenhower's Atoms-For-Peace program which is trying to say, well, we've spent all this money, we want to look a little bit better in the eyes of the world. Let's produce electricity. But you're using the same infrastructures, the same people, the same needs and desires you poured into here to--Shippingport was our first electrical plant and sure enough, that is the base product for our surface ships. So, a little bit of entangled there, it wasn't exactly Atoms-For-Peace and a conventional sense of what's the best way to produce electricity. Well, is that a good or bad decision? Well, I'm not sure I want to sit here and debate that but, you know, at the time, urgency of war, the fact that the weapons were unsophisticated designs, you needed a lot of material for it, the delivery systems were horrible, okay. And so, you needed a large number to be a credible defense, safety environment; those kinds of things weren't considered as much. Compared to today, obviously, the very efficient designs ICBMs are highly accurate, they need to scale down. We almost have too much material for weapons. And of course, safety environment proliferation issues are [INDISTINCT] concerns. Maybe it was right then, maybe wrong today, people can decide that. Well, in the tale of the nuclear reactor thorium, engineers don't want to give up. When they see a good idea, they dog it, even though programmatically and the money and the funding was completely cut off, they went around and said, "Look, air force, you don't--you don't have ICBMs yet. You need a credible defense to get your weapons out there, something that could fly a long time, how about this nuclear airplane?" Now, the only way that this would ever do in a normal reactor is if you have a liquid reactor. And so, they started a program, they sold air force on it as crazy it is. And I understand that somebody recently has said something in England, I believe about this. I would not like to see nuclear airplanes as our base of commercial flight. I can talk about that at some other time for the reasons for that. When this reactor program started out, they did 100 hours, a high temperature. I believe that maybe the--still a record certainly for the overall reactor running that long, that hot and that's 1,500 degrees Fahrenheit, very much hotter than most reactors can run. Two things that came out of this, one the fission products were naturally removed as you were pumping at it, which was really nice, to get rid of the poisons. And two, the load-following capability which was essential for the airplane application--in fact that you wanted to throttle something without control rods have instant response from the reactor and then throttle back if you needed to, to get your power. This reactor in the fluid method was able to do that on con--unlike on conventional or conventional reactors. Well, that program died pretty quickly as soon as the air force realized they could do the job much better with missiles. A missile program was--went full ahead and that one was cancelled. The engineers still wouldn't give up, okay. They [INDISTINCT] down in--or Oak Ridge National Laboratory in a small program but they ran a small program from '65 to 1969. And the main thing I'll say about this--we're not going to go to the great details of molten salt reactor Experiment was affected. They ran it 24 hours a day, three shifts everyday but nobody wanted--none of the engineers wanted to stay for the weekend. So, they shut it down on Friday night and they started it up regularly on Monday morning. Something that's totally, you know, not even thought about today in nuclear power plants. It is a base load, when it goes down, it goes down for a long time, you don't get to restart it. The end result today, most people think of molten salt as this gigantic reactor, something very large. They even have some control rods that's so large. Single fluid which means your thorium is thrown in with the uranium in the reactor itself. And you do--you do have a processing system; you have a freeze plug which I'll show a little bit later and you have this Brayton Closed-Cycle Turbine System unlike steam that is an advantage to this idea. Well, if this was so good and the common question is why wasn't it done? Well, hopefully I kind of hinted at that along the way the establishment on the plutonium industry and the needs there. The fact that this is a liquid system, it's daunting, it's different than just nuclear energy, it's a lot of chemistry involved, there's an existing mindset that had to be broken. And Dr. Weinberg who also hones the patents for the reactors we have today, who helped basically train Admiral Rickover and suggested what the reactor for the Nautilus, was. He was hoping that this reactor which he worked on for a long time would be the eventual power reactor technology that would use for electricity. Another person--his memoirs, deputy director at Oak Ridge also pointed out that it was an Oak Ridge project and therefore, it was considered just their own pet project and it was very hard to break out of that mold. Again, the existing bureaucracy--I've heard a lot of talks on the fusion as well, the same kind of mindset we are trying to break, what the common large program has in the government. All right, why is it so different? Liquid core, I mentioned that and the fact that it is thorium and that you have this chemical processing system. And you can see at room temperature--this is a crystal, it is a salt and when you heat it up, it becomes a liquid, a little bit thicker than water, you can pop it around. Last thing on the history, Admiral Rickover in his program, he managed to put together a gigantic organization to build not only the Nautilus but the whole nuclear navy and it stands today. He's done a very good job as far as establishing safety record and the navy is excellent in that but understand--inherently, it's not found in the reactor. It's found in the very strict rules, the blind obedience, the very well-trained--long-trained process that you have to do with the sailors that run these reactors. So here's the path that we've taken, the typical nuclear reactor with this giant vessel and the question is have we made the best decision then or are we making the best decision now? And I'm going to--then propose that LFTR is something that is what fusion promises. Some technical details; LFTR is a technology or architecture of a technology, I should say, it's not a specific design but it has certain design characteristics. Two fluids, the fact it's atmospheric pressure, very low pressure on the vessel. It's going to be high-temperature. It's going to have chemical extraction; I'll explain why that's necessary, thermal spectrum and then the Closed-Cycle Brayton System instead of steam. The reason why you have--this is the chart of the nuclides--the reason why we have to have extraction is that thorium with the--this is protons 90, it absorbs the neutron, it becomes thorium 233 which beta decay on 22 and a half minutes. Everybody knows what beta decay is--goes to protactinium. Protactinium, 27 days half-life, it also beta decays and becomes your fissile fuel. Uranium-233, that's what you'd want to get in your reactor fuel. Now what if we leave the thorium--I mean the protactinium in the reactor, this is what happens. You get the same beginning, you get thorium beta decaying the protactinium but now you have the problem of absorbing a second neutron which is fairly highly likely. And seven and a half hour--or seven hour--or half-life, it will also beta decay to uranium-234 which is not fissile. Now, you could absorb yet another neutron here and jump to 235 and with another neutron split the 235 but obviously, that chain is using way too many neutrons and the reactor would stop under that--on those conditions. And there's all this probabilities of how much absorption and there are other decay methods that you have to take into account. So, that's the main reason why you want to take out the protactinium out of the reactor. So, the architecture for LFTR starts out with the minimum core of fissile material that's hot. The four corners just kind of remind you of the--the basic print is what are you trying to--the goals you're trying to get to which is a safe compact reactor, something that--proliferation-resistant, waste reduction, covers that amount of electricity you need, that great big blue line and do it quickly as well as cost-effective being--effective connecting to the grid. So, the core is just hot, you can pump in and out, drives the turbines, you understand that. The blanket around it reflects the neutrons back in or the thorium that's in the blanket absorbs and becomes your protactinium. You have to take out the protactinium, there is the chemistry and let it decay and then that produces the U233. And you can actually extract the products--the fission products and other things out of the reactor as it's running in this liquid state. Look at the inherent advantage, this is against, systems engineering, everybody has desired goals and you kind of just specifically list, well, what are those goals were, the cost. Well, it's a low fuel price, low capital cost, long life, low maintenance so those kinds of things--transportation. You break all those down and you trace out what your inherent properties are to those and you see whether they're--you're matching up or you're getting what you really want to. So, if we pick a couple of these, here's liquid core, you've got homogeneous mixing which means you don't have any hot spots, which is a real concern in conventional reactors. If one spot gets hotter and it continues to get hotter until you have to melt them. You get to burn up all the fuel because it's constantly being moved around in the reactor and no fuel shut down because you can fuel this continuously. The expandability of the fluid gives you a large negative temperature coefficient which is where your safety is at. No separate cooling system, that's one less system and the big thing is the safety; the fact that if you're--there is no coolant to get rid off in order to have a meltdown or a problem. And of course, drainable, you know, I'll give you an example of that. If you have this very small reactor core and you leave a tube out there and this is very hot liquid--as long as you keep that at room temperature by blowing some air across it or in this case, helium--forced helium tubes, that salt will freeze. It'll make a plug, if you got a crack in this thing, actually it will actually leak out and probably seal itself, okay, depending how the design of this is. But the point is if you lose power, if anything happens; somebody throw a grenade in this thing this--or this gets hot, too hot for any reason, that plug will always melt and drain into a passive pan which is going to hold the heat and then the radiation. If everything is okay, you just heat it back up or even turn it right back on and if it's liquid state, it takes a little while for that heat to dissipate and you can pump it back in to start up. So, instead of being like really cautious about shutting down your reactor because you'll black out half the neighborhood or whatever and take days or months, if not years to restart, you can go ahead and shut things down and go, "It was just a mistake." And immediately go back on line. So, actually there's inherent safety in there because you could use your safety system all the time. Actually, I need to go back. All right. Thorium advantages here, that it was abundant, I mentioned that and the fact that it's not fissile, okay, it means it's not weapons usefulness in which case the less terrorist interest again goes to cost and safety, security, can't explode. Look at the uranium cycle compared to the thorium cycle, you start out with a whole lot more mining with the uranium cycle, you have a whole lot of yellow cake that you make, everybody recognize that but then you got to enrich that and then make these pellets. It's a very expensive process; the security to do this process is very expensive much less the actual process. You end up with a whole bunch of depleted uranium, it's still useful in some ways and not useful in others so I don't know what people were doing with that other than letting it sit on the ground, it doesn't go to Yoko Mountain. You need a very big plant, as you saw before, you--a very large reactor with a vessel that can hold a ball of steam or any explosion that can happen here because of the very high pressure. Big turbine plant next to it and you produce a whole lot of spent fuel and you need Yoko Mountain for 10,000 years. The thorium cycle, you need one ton, this is for the same amount of energy, one giga watt for one year and much more plant, low pressure, the Brayton's are much smaller, much more efficient as much as 50% efficient or better compared to about 35% best you can do for steam, one ton of fission products. But the big deal here is that in--within 10 years, most of that, 83% is going to be backed down to safe radio--background levels, which means you can take those products which actually were produced in the reactor, there's some very interesting things you can get out of that and you'd sell some high quality materials. And the remainder only needs 300 years approximately for storage, which you can imagine that--the finding a many places around the world that can handle that and you can imagine making storage vessels that are, you know, casts that can last 300 years. Well, proliferation risk; one of the things that happened with this particular process with the LFTR processes as we see it, there's going to be a little contamination of uranium-232, you just can't help it, I'll show you that in minute. And it has a decay chain; it gets you down to thalium-208 which has a hard gamma emitter which makes it a very nasty stuff to deal with. This is where the uranium gets in--the 232 becomes. There are certain reactions that can happen. I don't have time to go through the details. If you have 1% of uranium-232 in the material and you're holding it, you have about three--or three minutes, I believe--well, less than three minutes before you get your full five rem dose which is considered, you know, your top level. I think it's within a half in it--no, within--yeah, half an hour. You're feeling the effects of radiation poisoning and a couple--and within two hours, you're probably likely to die. So, it's very hard to handle, it also means separation of a nation who wanted to use this as a material for weapons, it would be a hot enrichment environment to deal with. The radiation hurts the electronics as well as the explosive material within the weapon so they don't shift--they do not--their long--not very long half-life as far as the shelf life of the reactor--of the bombs, so. Okay. On the fluoride salt itself, ionic chemical stability is very important. I'll show that in a minute. The fact that it's very high temperature and a little vapor pressure means you run very high temperatures. And again, each one of these things room set, temperature solid, like I explained before leak resistance, et cetera. So, look at the radiation damage in a conventional nuclear reactor. It's going to have cladding, all the temperature and heat is built up within that cladding and that cladding can't break. So--or you lose the noble gases, the krypton and other things that were radioactive. And so, you end up having to pull out this core all the time and not burn up all the fuel because there's physical damage being done to the solid, where is if it's ionically-bonded in a liquid, the ionic bonds don't care. They're going to move around as they need to and reassemble and you always have that ability to withstand a lot of punishment in the reactor. Another point of this is that the salt are actually very low corrosion and the way to briefly demonstrate that, here is a typical salt in the reactor and the larger the number, the better minus 104 and this the freeb--free energy--Gibbs free energy here. A chemist will say you need a difference of 20 between it and let's say a wall material, or a vessel material such as--here's iron and you can see that's about double the difference between those two. So, it's pretty chemically stable, considered almost a noble chemical reaction in the reactor. Internal processing; we have minimal, physical--inventories so if the reactor is small, there is no fuel fabrication, obviously that drives a lot of your cost and the big thing is you can extract both poisons and valuable materials out of the reactor. This is a little more detailed than the one I had before. What you're doing is you're pumping out of the core and your fluoride--just fluoride gas through the salt and all the uranium products are going to come out as uranium hexafluoride, which means it's a gas and you pull it out and it re-introduce any uranium that it has not burned into the reactor. The rest of the salt goes through, you get back some distillation, get out the fission products and what's left here is you can separate this. And this will probably take an economic analysis of how much time and effort would you do to separate these things. You do need a central location plant where you take little bottles every once in awhile out and centrally process or do you incorporate it like you do the actual breathing process within the reactor itself? This would all be self-contained in a reactor vessel. The blanket on the other hand comes out and I'd like to think that is a--it's a reactive extraction column--if a chemist--it's like a catalyst. But they say that's a bad word so don't use it. For me, it's a catalyst in nature. In fact, that you put in the thorium appear and the thorium will go back into the blanket salt and replace the protactinium which can be extracted out and put in the decayed tank. Same thing here, you just flow gas through that, fluoride gas, all the uranium that's produced, whenever it's produced is able to be put in--back into the salt and back into the core. And very quickly on the Closed-Cycle Brayton, just to say that this could be air cooled, heat rejection as wall as verbal impact pressure allows you to play with the size and the efficiency of the system. And this just shows--this is the advanced boiling water reactor typically looked at. And again, a very large building, no matter how you do these things, the LFTR concept would be very much smaller, the whole reactor core would be something that size with the entire Brayton system not much bigger. And it just shows again the difference in size of a comparison of a Brayton system versus steam plant and some of the listing of reasons why you would think that the cost of this whole system would be significantly less than existing nuclear power plants. Okay. Well, the disadvantages, I think I explained some of these. It's unknown; it's going to be different from what the existing infrastructure is going to support. It does need a charge of uranium-233 or some other fissile material but we suggest doing that because it keeps it--the whole reactor clean. And here's a comparison--basically, I've covered most of these, everything from the waist--relative waist 130th, 10,000 years versus 300 years, the fact that you can burn almost 100% versus 1% and the best reactors are planning a couple of percent maybe, two or three of the total fuel usage, as well as being higher efficiency, lower pressure, air, water cooled. And in unique applications, this should scale down as well as scale up if you want to make large plants but it also could spill onto the back of a semi-trailer, that size typical. It would obviously be very advantage to the navy because even in their smaller vessels, they can't build these--their existing reactors to fit into the [INDISTINCT] ships that they have. We like to talk about submerged units because they're really not seen. They put them in rivers and they're very small, very invulnerable to attack or other things. And then if you really want to use other processes, high temperature directly from the reactors, it's very useful for--one is mobile. It can go to a site for shell oil extraction. It's--it couples very well with desalination for water processes, hydrogen production as well because of the high temperature nature of the reactor core. So hopefully, I've covered a--the brief background. These are the main things that we try to achieve with the technology. Those were the driving goals and then how you would actually put the reactor together or so the specific details are driven by what you're trying to get out of it. And the primary reason why most people look at thorium is because of the unique nature of being able to produce a huge amount of energy for a very small amount of resources per mega watt being produced and can readily be put together fairly quickly. So this time, I'll take questions. Yeah? >> The U233 that's re-injected in the core, how do you keep the 232 out of it? I mean, it seems that you introduced 232 and that it's something you don't want to go anywhere near it. >> BONOMETTI: All--the--what happens to the core when you introduce the 233 and the 232 in the reactor core? Well, first of all, a reactor--or any reactor is very, very hot and you can't go near it. It's going to have a lot of radiation going on. So, adding the 232 in there is not making any significance difference in the overall radioactivity in the core itself. Definitely, there is a small poison that sits in there but it's a very small trace amount. It's when you take it out that unless you separate it out, you always have hot uranium and the difference is the separation is chemical separation versus the uranium-233 which is what you want for the weapon and uranium-232 which produces this gamma all the time and it's the key chain. It has to be done with separation techniques that are more common to weapon development. Did I get the question right in it? >> I was just wondering if it makes the design of the reactor [INDISTINCT] because the U233 is actually part of the process? So, you know, if the materials you use for example is part of the pumping, you know, we would run into problems if your plant becomes contaminated with some 232. >> BONOMETTI: No because there's--again, the question, I--it was--is there an issue with the 233, 232 in the reactor core or as it comes out through the piping because of this radioactivity. The decay products in the reactor overwhelm that. There's just one small source. The reason why it's significant for proliferation issues is the fact that it's hard to separate because it's from the stuff you want because it's still uranium, chemically. As far as the reactor itself, any of the pumping of the pipes and everything else is going to see some level of radioactivity just because of the decay products. Those decay products--what's nice about this reactor are always kept in a minimum because you can take them out. The gases, anything like krypton or whatever comes out in the pumping process. So, it's actually a cleaner reactor if you want inside the reactor and it wears and tear radioactivity-wise less. Yes? >> What's your estimated cost for the consumers say, I don't know, a wholesome price or retail price if you were handling--what are the barriers to presume? >> BONOMETTI: What is the price at the meter at the end of all this? We haven't gotten that far in economic development of what that would be. The argument here is that the technology and the research has been done and there is a systems engineering point of view that you will say, "It will be less expensive." Exactly, we're estimating 20 to--or I think it was at 30%-50% less a more specific design. Remember, everything is being done on everybody's own time. This is a grass root effort that, you know, we hope that somebody with the government or somebody else wants to pick this up, it's all free knowledge but that's--it was a great question. Did I answer the other part of the question? There was cost, electricity and then? >> What are your barriers? So basically, [INDISTINCT] >> BONOMETTI: Well, the barriers--to put this together? >> Yes. >> BONOMETTI: Couple of them. One of them would be that, you know, the nuclear industry is run by the--by the government. You're going to have the government blessing on something unless you leave the United States or whatever. There are other countries that are looking into thorium but again, not significantly. And so, I think the barrier is, you know, those types of things. It is a nuclear process and you're going to have to deal with the proper regulations to make--meet that. Yeah, you go. >> [INDISTINCT] and can you explain that [INDISTINCT] >> BONOMETTI: Negative--yeah, let me go back to the slide. The--basically, it's the ability of the reactor to respond in producing less power as the temperature goes up. So, as the reactor core--a normal reactor, when the temperature goes up, okay, there's--usually the core temperature--what do you call it, is moderated with the water and you get less power being produced. Okay. Maybe you flow more water through the reactor, for example. This expands itself, the core being liquid squeezes out and the less density you have, the less fuel you have in the reactor, therefore the less energy you can produce. >> [INDISTINCT] it's thermal [INDISTINCT] >> BONOMETTI: So it's thermal. It's based on thermal expansion on how much fuel you're actually having in your reactor. In the same token, if your generators are producing more electricity because of the higher demand, it sends back that fluid colder which is denser and therefore it will have more energy and it is a natural process within the reactor itself. That's a common nuclear, you know, I guess determination of how safe a reactor is. It's how good that coefficient is. Yes? >> [INDISTINCT] what are the engineering challenges involved? Like, it strikes me that, you know, pumping extremely hot in both senses of the word salt through pipes and pumps and such, it might be a really difficult thing to do. Could we build one of these [INDISTINCT] >> BONOMETTI: The Engineering challenge is--I guess, is the question pumping hot salts to pipes and those kinds of things. We do that on a regular basis in the industry. A lot of processes--a lot of industrial processes use the same kind of hot salt a chemical industry uses. So, there's presidents that would pump manufactures that do that kind of thing. The temperatures are hot but not, you know, something that's not done everyday in commercial industries. The--obviously, the safety requirements for everything--you are talking about a nuclear reactor, it's going have to be really good pumps and the paperwork is a mile high to make sure those pumps are, you know, adequate. But again, even if the pump failed, it doesn't--you can drain the tank and it will naturally get hot if the pump stops pumping. The core will get hot over heat, pour out into your tray and stop it for you. So, if the--there's nothing inherently that the industry can't do. It is a big systems engineering problem to make one that's cost effective, that's safe and meets all requirements and that all the little details were taking care of but nothing that we've seen. Yes? >> Yeah. So, I'm guessing there's some kind of GEN-4 reactor development thing happening, you know, a little brighter or something like this. It looks like six different designs that they're pursuing and this is one of them but can tell us a little bit about what that is, like what expenses get funded, how do [INDISTINCT] bigger, you know? >> BONOMETTI: Okay. The question being, what is the GEN-4 or how does that play in with this. GEN-4 is a department of energy initiative. It's probably a good one in some ways. They're looking for what's the next generation reactor. Technically, malt and salt not LFTR which is slightly different is under their category of GEN-4. My personal take on it when I look at the amount of money they're putting in, I'm not--I'm not sure they're very serious. I think it's--and a round of--and don't quote me, but $40,000 which is enough for one person to go out and write a paper and go to a conference, whereas the other projects are getting much more serious money. You know, I'll let other people decide what the track record of the Department of Energy is in, you know, solving energy problems at this point. >> [INDISTINCT] which is--so Kirk Sorensen had got his blog on the [INDISTINCT] so that's one sort of [INDISTINCT] of work on this kind of thing [INDISTINCT] >> BONOMETTI: Yes. Kirk Sorensen and I are, you know, this is our--LFTR is that. And that thorium forum is probably the key repository in which people all get together and work on. >> So, there was another thing in France and then there was Per Peterson up in Berkeley working on this stuff... >> BONOMETTI: There are several people that--you are asking who else is working thorium? >> [INDISTINCT] still working on this stuff or he--like, results finding and then goes to something else? >> BONOMETTI: I think he's kind of moved on to other things. He was at the Department of the Energy, I believe and so I don't--I don't really know the total status. Everybody's got their little ideas of how to use thorium and some of them are just to add thorium to a reactor--the existing reactor and qualify that fuel. Now qualification of a fuel for any reactor is a long, expensive process and the question is if you're going to spend a lot time and money and put it into the commercial reactors that are running fine or are safe. I would say maybe that's a little too much money, a little risk you're doing trying to add it but that's--that is a solution for thorium. Thorium in a pebble bed is another one that people have talked about. It's a little bit better than maybe the conventional reactor. It's looking more and more like a liquid system. My point is I think you should go to liquid system and burn all the fuel because in a pebble bed or these other concepts, you don't burn all the thorium and you still have a lot of waste that you get rid off. Yes? >> Is this something that you [INDISTINCT] design to build through private funds or is it something that you have to have government funding involved in them? >> BONOMETTI: Private or government funding. Well, that's up to individuals. Again, the organization--the [INDISTINCT] organization that I'm really representing or working with doesn't have any answer to that. It is--it would be daunting for private funding, it could be done for private funding. Certainly, the navy would be a prime example of wanting something like this yet the navy has the same problem that the Department of Energy does. They're kind of fixed in a certain pattern. It's very hard to break that. So, if somebody wants to take it to the next step which is maybe demonstrating the chemistry without the nuclear material, a private company would have to have some backing from the government to say, "Yes. You can use uranium-233." Which there is actually a lot of stored and they want to blend it down and throw it away. That's a said way the government is looking at this. They haven't done it yet but there are plans for it. So, if I was a private company or private funds, the first thing I'd make sure is I had somebody in the government side saying, "Yes. We will hold that fuel. And yes, we will let you utilize that," because you need some kind of seed--fission material in order to start the process. Okay, any other questions? All right, one more. >> So you're not [INDISTINCT] pursuing a path making--I mean, you're obviously making it invisible but is there a free path of, you know, getting the government to go in on this to get research? >> BONOMETTI: I think there are efforts that--I guess, you're question is, you know, what are the paths that we're pursuing or the path that could be pursued to get this going other than the education process that we're attempting to do right now? Yes, there is. There's attempt to talk to people both in the government. When I was Naval Post graduate School, the students that had designed projects found that it was very interesting what it could for the navy as far as capability and ships. We need to do some more studies like that. I suspect that is going to come out, I think in the next six months because of all the energy research that's going to be done or analysis is going to be done just to find out which way we want to go. The thorium will be--and LFTR specifically will be thrown in that mix. What comes out or who stands up and says, "Yes. Let's do this," or provide funds to do this, that remains to be seen. And I have talked to other people, you know, privately about, you know, what specific paths we've done, you know, and share that information. Okay. No--last minute question. One more, okay. >> Okay. So, in considering--yes, it seems like if the problem is kind of just bureaucratic like, you know, mindset, roadblock kind of going to the to but, you know, Obama had said that you [INDISTINCT] anti-nuclear, go to the administration and say, "You know, what can you do to consider this and make it, you know, maybe--you can actually take it seriously?" >> BONOMETTI: Yes, going to the top. Again, not really a question but a statement of going to the top all way, the administration and getting him to look at this and, you know, point the agencies or money in that direction certainly would help. I mean, that's the easy path if we can do that. People are working on those kinds of things. Like I said, I think it's a credible story, enough to keep it in the mix, enough to look at it seriously and enough to seriously look at why has it not been promulgated to this point? What are those roadblocks and is it just, you know, the bureaucratic--bureaucracy that we have? That's a good question. Okay. Thank you very much.
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Channel: Google TechTalks
Views: 358,500
Rating: 4.8427472 out of 5
Keywords: google, techtalks, techtalk, engedu, talk, talks, googletechtalks, education
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Length: 55min 17sec (3317 seconds)
Published: Wed Nov 19 2008
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