Is Thorium Our Energy Future? | Answers With Joe

this video is supported by brilliant org let's set the scene it's May of 1986 and much like Homer Simpson you work at a nuclear power plant a nuclear power plant that just melted down and now a control reaction overheated the cooling tanks causing the water inside to evaporate expand and explode destroying all the water pumps that was in the coolant to the other reactor cores sending those into overdrive and melting down as well the reactors basically turn into a 5,000 degree molten massive steel concrete and enriched uranium and firefighters arrive dousing the building trying to put it all out and stabilize it which they succeed in doing but they all die within hours every town in a 500 kilometer radius is evacuated due to toxic levels of radiation from the blast hospitals are completely overrun with patients so much so that they actually decide to just reclassify what is considered a treatable amount of radiation and just send people home to die so you're doing everything you can to help when authorities come to you and say that they're looking for volunteers because it turns out that all the water that the firemen had doused the building with is now leapt down into the basement level in that giant mass of radioactive goo that's as hot as the center of the earth is melting through the floor above it if that goo manages to get down into the flooded basement the steam explosion that would come out of that would be large enough to contaminate several nearby countries the basement needs to be drained and the only way to do that is to turn a valve in the basement volunteering means almost certain death but not doing it means millions of people could die do you do it the event I'm describing is of course the Chernobyl disaster and believe it or not three men actually volunteered to do that they threw on wet suits they walk through waist high water and pitch-black tunnels and avoided an unimaginable disaster Chernobyl is the poster child for the dangers of nuclear power but despite that and other events like the Fukushima event nuclear powers actually considered pretty safe but what if there was something even safer and cleaner it's also cheaper and more efficient turns out there is [Music] oh mighty Arjun Justin Carmona's Shan said gasps Ian Prado Caleb Robinson and many more asked for a video on liquid fluoride thorium reactors I did a series of videos a while back on renewable energy solutions and a lot of people felt that I should have included nuclear in that but I didn't because nuclear fuel still has to be dug out of the ground and enriched in all that kind of stuff but nuclear energy is still considered to be clean energy because though it does produce waste it's contained waste it's not vented into the atmosphere piped into the ocean or anything at least god I hope not we're reaching a bit of a crisis point right now because we seriously need to reduce our carbon emissions if we're going to avoid the worst effects of climate change of the next hundred years but at the same time our global energy use is increasing mostly due to developing nations that are becoming electrified this is a trend that will continue so although there are some issues with nuclear energy this is one of those things that we can't just shove aside we need to be examining every single resource we have available to us right now and this isn't something we can use wait for AI to solve because well we know what they're gonna do so let's start off by looking at the kind of nuclear energy we've been doing so far so that we have a good starting point traditional reactors use uranium as fuel uranium is one of the heaviest elements on the periodic table with 92 protons and it occurs naturally in the earth in the form of two different isotopes uranium 238 and uranium 235 isotopes are different variations of an element that contain the same number of protons but a different number of neutrons hydrogen for example has one proton but it's isotope deuterium has a proton and a neutron and tritium has one proton and two neutrons do it blah Greenham 238 and 235 correspond to the combined number of protons and neutrons in the nucleus the 238 has 146 neutrons for example which means the 235 has of course 143 nailed it this means uranium-235 has fewer neutrons to hold the nucleus together which means it's more easily split if it's hit by a radioactive particle when the nucleus is split it gives off heat and flings out a few stray neutrons in the process if those neutrons hit other atoms of uranium-235 we can cause them to split which fling off more neutrons which can cause more atoms to split causing a chain reaction this is known as nuclear fission and it produces a lot of heat from a tiny amount of material and nuclear bombs this heat is used to melt cities in a nuclear reactor it's used to boil water and create steam which turns a turbine and creates electricity in order to do this natural uranium has to be refined into uranium fuel and the way they do this is they mine the ore then they dissolve the wringing them out of the ore using acid this creates a uranium oxide concentrate called yellowcake they then take this and convert it into a gas called uranium hexafluoride and from there it's enriched in nature only 0.7% of uranium is the uranium-235 after enrichment it can get it up to 5% after enrichment this is converted into uranium dioxide which is formed into uranium fuel pellets fuel pellets are inserted into rods which helps absorb strain neutrons then that's put into a moderator which absorbs more of the strain neutrons all of this is meant to cool the reaction and keep it from going out of control so while the straight neutrons split the uranium 235 it's actually absorbed by uranium 238 which turns it into the rain 2:39 atoms that are split by a neutron are called fissile in atoms that absorb neutrons are called fertile so the uranium-235 is basically impregnating the 238 in this hot radioactive orgy ooh this uranium 239 quickly decays into neptunium 239 was then decays into plutonium 239 and that's when it runs out of planets to turn into this is known as the uranium plutonium cycle or the upu cycle once the uranium 235 gets down to around 0.3% that's considered spent fuel and what's left over is a radioactive stew of high mast isotopes called trans uronic isotopes that have to be carefully housed for at least 10,000 years or used to melt cities potato potato actually no potato because all of the science was figured out during World War two and at the time they were more interested in melting cities which is why they focused more on uranium and not on another possible fuel source thorium sits two squares over from uranium on the periodic table with 90 protons and it's considered a weakly radioactive metal and yes it was named dr. Thor the Norse god of thunder thorium is a fairly abundant material there's four times more of it in the Earth's crust than there is uranium and all that very trace elements of it are the isotope thorium 232 thorium is stable in non-fissile which means you can put as much of it together as you want and it won't spontaneously burn on you that's good the thorium is fertile which means if you bombard it with neutrons it will absorb a neutron and create thorium 233 thorium 233 is not as stable as 232 and it quickly decays in the protec tinium 233 which then decays down into uranium 233 uranium 233 behaves a lot like 235 and then it's highly fissile in fact it's actually more efficient than 235 233 burns off at 91% 235 burns off at 85% from here you can separate out the uranium 233 into a pure 233 concentrate and then use that in a reactor just like you would normal uranium 235 the difference is you don't have the 238 in there to absorb and turn into plutonium and all these other nasty things and the end result is a spent fuel with a half-life of 300 years 10,000 years and all that explains the physics of the fuel cycle and why it does what it does but that's only half the story the rest of it is an engineering why don't we take these fuel cycles and use that to create electricity well the simplest answer is we use that heat to boil off water and then the pressurized steam is used to turn a turbine which turns a generator which creates electricity and there have been literally dozens of different configurations of this over the years that increase the efficiency and safety of this whole thing way too many to talk about here but I'm gonna focus and break down the most popular one which is the pressurized water reactor or PWR reactor which looks like the word power of course in a pressurized water reactor a highly pressurized loop of water is circulated around the reactor core this serves both as a moderator and a coolant but it also is pressurized so that it can absorb more heat without boiling this loop passes through a steam generator tank which is part of a second closed loop the heat from that first loop boils off the water and the steam generator tank which creates steam which turns the turbines and does all that kind of stuff and now cooler pressurized water is pumped back into the reactor core where it cools off the reaction but also absorbs more heat and start the process all over again and the steam is reconvince down into water and then pumped into the steam generator tank now of course this relies on a constant flow of water to keep the reactor from getting too hot and melting down which is what happened in Fukushima when the tsunami knocked out several of its backup power generators now to clarify Fukushima was not a pressurized water reactor it was actually a boiling water reactor which skips the whole closed-loop thing and just uses the reactor to boil off the water to turn it into steam but it's the same idea now Ithorian you don't have to worry about the reactor overheating because the whole thing the whole fuel cycle revolves around being bombarded with neutrons to begin with so if you cut off the flow of neutrons then you stop the whole process so a pretty brilliant solution is to take the thorium in the uranium and dissolve them into a salt compound with a freeze plug at the bottom of the reactor that way if it gets too hot the freeze plug melts and all of that drains out taking it away from the source of the neutrons and automatically shutting everything down and this is known as a liquid fluoride thorium reactor or LFTR lifter you probably thought I wasn't gonna get there I got there lifter is a type of molten salt reactor which is a very promising technology that there's been a lot of talk about some of it pretty bombastic so let's just break down the pros and cons here first of all they're incredibly efficient uranium reactors only actually burn about 1% of the fuel but because the fuel on the lifter reactor is liquid you can actually process the fuel while it's in use which means you can take out the fissile products that could be absorbing strain neutrons this way all the neutrons are working to continue the chain reaction this is called Neutron economy the assemblies of the reactors are much simpler there's no fuel cells no rods no pressurized water it's basically just a vat the soft compounds allowed to take in a lot more temperature without it being pressurized higher temperatures means more water gets boiled off more steam which creates more electricity and since it's liquid it can be refueled while operating so it's less downtime and the containment is smaller because it's not pressurized this means you can have smaller decentralized modular plants now no system is perfect including lifters so let's talk about the cons which include the corrosive nature of the salt compounds means that there's gonna be a lot more material degradation which means that there's gonna be a lot more maintenance it has to be done especially around the containment vessel and keep in mind this is gonna have to be done remotely because the containment vessel is gonna be highly radioactive now many are saying that you can't make a bomb with the waste product like you can with the uranium reactions and this is true but the process of making the thorium reaction involves creating uranium 233 which is weapons-grade uranium now obviously the point of making that 233 is to use it in the reactor but if a plant owner or we're gonna ferry a third party wanted to get a hold of it and make a bomb out of it they absolutely could and one last thing an inevitable byproduct of the thorium uranium fuel cycle is eventually you're going to create a uranium 232 isotope which can degrade down to thallium 208 which produces a two point six MeV gamma ray burst this is very high-energy radiation which can be hard to shield so while the eventual end product is not as radioactive and the interim it can actually be more radioactive so even though there are no lifter reactors working today we do know that it does work because there was one that was built in the 1960s it was called the molten salt reactor experiment it was carried out at the Oak Ridge National Laboratory in Tennessee it was conceived in nineteen 60 they got it up and online in 1965 and it ran until 1969 all the while they experimented with it they tried out different solutions in the compound different configurations and the reactor and they figured out how to make it work and it did it worked so why didn't it take off well the conspiratorial reason you're gonna see all around the internet is that the United States government wanted to use the uranium process because they could use the waste products from that to make bombs but the thorium process creates uranium 233 which you can totally use for bombs so that's not really the case now you can make the argument that the initial research was being done to create an atomic bomb and all we had at the time was that natural uranium and that's a perfectly valid point but I think ultimately by the time the Oakridge boys figured out how to do lifter the inertia was already behind uranium and that's just how it worked out you know VHS went over beta the best solution doesn't always win but whatever the reason they did choose to focus on uranium and in fact there was a larger version of the molten salt reactor experiment called the molten salt breeder reactor that was going to be going into production but the Atomic Energy Commission defunded it there are however some signs of slow progress out there in Europe there's a reactor called the Mozart reactor that they're working on in Japan there's one called the Fuji MSR that is a joint effort between the US Japan and Russia but more promising China actually has gotten involved and they've invested 350 million dollars in a reactor and they brought in a hundred and forty phd's to work on this with a plan to get it up and running in about 20 years and you can't talk about liquid fluoride thorium reactors without talking about Kirk Sorensen he has been a huge advocate of it he's done TED Talks and he runs a company called Philby energy where his goal is to build modular small reactors for government bases military bases around the world you can find a lot of his videos on youtube he also has a website called energy from thorium comm so with a little luck maybe in the next decade we'll start to see some of these new reactor concepts coming online things that are much easier simpler more efficient and safer so that may be something like Chernobyl will never happen and this is a huge subject there's a lot that I had to leave out and I'm sure plenty of things I got wrong I've been asked about this subject quite a bit so I know you guys are really interested in it you guys ask questions and talk it out in the comments down below by the way if you want to get an idea of how the pressurized water reactor works all you have to do is look at the back of your refrigerator those coils in the back of your fridge are actually pressurized air that was compressed from inside your refrigerator and when it's doing back there is it's radiating out its heat and cooling the pressurized air so the when he gets deep pressurized inside the refrigerator it's far cooler that's what keeps everything cool and you know where I learned that from brilliant dog work they've got of course I'm brilliant org that's all about the physics of the everyday where they explain everyday things around you like your refrigerator and I've got to be honest when I was researching for this one and I saw the whole thing about the pressurized water reactor I was like yeah that's kind of like a fridge to me that's what learning things is all about you know the connections that you make the new understandings that you form in areas that you never would have thought about and brilliant superpowers that part of your brain because they kind of walk you through the process of figuring these things out for yourself which is a much better way to learn things brilliant has entire courses on things like renewable energy physics logic problem solving that can apply in your daily life in ways that you never would have thought before sign up for free at brilliant org slash answers with Joe and get access to their free daily puzzles and brainteasers to kind of help you stay smart and the first 295 people who sign up for a premium membership which gives you access to all of their courses get 20% off your subscription for life I've really been enjoying it I'm sure you will too Brandon org slash answers with Joe links down in the description thanks to brilliant for sponsoring this video and a special thanks to the answer files on patreon who help support this channel keep the lights on around here this is kind of what I do now it really does make a difference and I appreciate it there's been some new people that 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subscribe I come back with videos every Monday alright thanks so much for watching you guys go out have an eye-opening week and I'll see you next Monday love you guys take care

Channel: Joe Scott

Views: 1,017,456

Rating: 4.789341 out of 5

Keywords: answers with joe, liquid fluoride thorium reactors, thorium, thorium 232, uranium 235, yellowcake, uranium enrichment, nuclear energy, nuclear fission, molten salt reactors, uranium hexafluoride, molten salt reactor experiment, kirk sorenson, clean energy, future energy, thorium reactor, radioactive decay, nuclear waste

Id: XMuxjHLLk0E

Length: 16min 58sec (1018 seconds)

Published: Mon Feb 12 2018

Reddit Comments

[u/espresso__patronum]

Some corrections from the video:

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10:01 PWRs release 1% of their fuels energy value.

Actually less than 1%, Light water reactors release about 0.5% of their fuels energy value, and heavy water reactors release about 0.7%, they both do terrible.

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10:49 Corrosion is a major concern holding back LFTRs.

Hastealloy-N is a superior material for resisting corrosion from molten fluoride salts.

http://www.haynesintl.com/alloys/alloy-portfolio_/Corrosion-resistant-Alloys/hastelloy-n-alloy/principle-features

"corrosion attack on HASTELLOY® N alloy in molten fluoride salts at temperatures up to 1300°F (704°C), was less than one mil per year"

Please note:

A mil is a measurement that equals one-thousandth of an inch, or 0.001 inch. One mil also equals 0.0254 mm (millimeter). Thus a mil is not the same thickness as a millimeter. The term "mil" is not an abbreviation but a unit of measure.

http://moltensalt.org.s3-website-us-east-1.amazonaws.com/references/static/downloads/pdf/ORNL-TM-6002.pdf

Neutron embrittlement and cracking of the Hastelloy-n was resolved by the addition of a small amount of niobium.

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11:03 U-233 bred from thorium can be used in weapons.

Yes very pure U-233 with 5ppm or less U-232 contamination could be used in weapons. That however is exceedingly hard to make compared to the proven route of U-235 enrichment or breeding of Pu-239 from U-238.

Any fission reactor's neutron flux can convert U238 to Pu239 or Th232 to U233, but the best designs make that incredibly difficult and expensive.

There is no way to prevent a determined government from building a weapons program from a modified power plant. This is why they are inspected by IAEA. IAEA monitoring (or refusal thereof) makes this public knowledge.

Any government that has the resources would opt to go the proven route of U235 or Pu239, rather than have to deal with potential U232 contamination.

Robert Hargraves is a study leader for energy policy at Dartmouth ILEAD.

Robert Hargraves graduated from Brown University (PhD Physics 1967)

http://www.thoriumenergyalliance.com/downloads/American_Scientist_Hargraves.pdf

"The uranium-233 produced from thorium-232 is necessarily accompanied by uranium-232, a proliferation prophylactic. Uranium-232 has a relatively short half-life of 73.6 years, burning itself out by producing decay products that include strong emitters of high-energy gamma radiation. The gamma emissions are easily detectable and highly destructive to ordnance components, circuitry and especially personnel. Uranium-232 is chemically identical to and essentially inseparable from uranium-233."

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"Only a determined, well-funded effort on the scale of a national program could overcome the obstacles to illicit use of uranium-232/233 produced in a LFTR reactor. Such an effort would certainly find that it was less problematic to pursue the enrichment of natural uranium or the generation of plutonium."

"the proportion of U-232 would be about 0.13% for a commercial power reactor. A year after separation, a weapons worker one meter from a subcritical 5 kg sphere of such U-233 would receive a radiation dose of 43 mSv/hr, compared to 0.003 mSv/hr from plutonium, even less from U-235. Death becomes probable after 72 hours exposure. After ten years this radiation triples."

"resulting weapons would be highly radioactive and therefore dangerous to military workers nearby. The penetrating 2.6 MeV gamma radiation is an easily detected marker revealing the presence of such U-233, possibly even from a satellite."

"For personnel safety, any U-233 material operations must be accomplished by remote handling equipment within a radioactively shielded hot cell. This can be designed to make it very hard for any insiders or outsiders to remove material from the hot cell."

Thorium Energy Cheaper Than Coal - Robert Hargraves

https://www.amazon.com/THORIUM-energy-cheaper-than-coal/dp/1478161299

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13:46 Fill-bee energy.

Flibe energy is pronounced FLY-B Rhymes with Tribe, not fill-be.