think im addicted to these videos

I do want to extend my gratitude providing this information to the public. Even if, we cannot effectively solve the chemical process of thorium breeders, this research should not be buried. Nuclear research has been way too focused on uranium, and we need to be exploring all facets of nuclear research. Even if the end result comes to making existing nuclear reactors more efficient.

0:27 The Basic Idea 💡 4:06 Why Bother Doing This? 11:42 27 Days 12:40 Why Not Bother?

Finally!!!! An information I can trust about thorium!

The thorium breeder cycle in a molten fluoride salt reactor is advantageous because it's the only breeder cycle that can be implemented using thermal neutrons. You can't do this with a U238 -> Pu239 breeder cycle. This allows smaller reactors to be built, as your fissile inventory can be much smaller. From an economic standpoint, this would enable many places in the world to have a reliable, dense energy source.

A civilization is great when old men plant trees they will never sit in the shade of.

I enjoyed watching it again.

Thorium reactors can be used to devour current nuclear reactor waste and convert that to useable energy. Indeed, Thorium reactors will use up over 97% (if memory serves me) of its fuel whereas current Uranium based fuels only utilizes 0.6% and the rest goes into the trash heap. Still, like you said, we'll never run out of Uranium and a lot of the waste may be recycled, but still, Thorium reactors is just the better way to make power, but of course more research has to be done since the work done by Oakridge Labs back in the late 60s/early 70s has to all be be redone, unfortunately (thanks Nixon). :)

If I understand the Thorium reactor correctly, then they are actually able to burn reactor waste from the traditional nuclear reactors. And that might make them an economic viable option for waste management.

15:17 - Exactly .... totally brilliant. I am so tired of people who don't know what they are talking about raving about "thorium" and "molten salt" and how great it would be. IllinoisEnergyProf gives us facts and context to understand them. Thank you very much Prof. Rusic.

I'd say there are a few more advantages of a MSR (especially the LFTR design). For example, the higher temperature of the molten salt offers safety features beyond just the passive freeze plug capability. Unlike water, you don't need very high pressure to keep it from boiling; it can operate at lower pressure than a LWR. And since the fuel is distributed as a fluid, as temperature rises thermal expansion reduces reactivity (passively). The higher temperature also means high thermal efficiency. With a MSR you also don't have the same concern with hydrogen gas build up and potential hydrogen explosions, when comparing with a LWR. A MSR can also be refueled without shutting down the reactor, and doesn't require (very costly) solid fuel manufacture. And there's no xenon poisoning. That's probably just scratching the surface. I understand the economic argument, but I can't help think it's a huge pity. I think the relative simplicity and especially the obvious safety advantages a MSR/LFTR design offers should justify R&D to overcome remaining obstacles. Public perception could make a difference in the economic sphere (not changing the economic cost, but shifting the willingness to pay those costs). Personally, I'd rather advocate for what I think is the best technology in the hopes of shifting both public and government perceptions about nuclear power, its safety (or potential safety), and the best path forward. Futile? Perhaps. Worth advocating? I think so. I'd say you're probably correct that it's more likely to be a long term goal in the current context, but pushing to shorten that lead time (and maybe adjust some of the variables in the current context) can only help, in my opinion.

I don’t think you fully appreciate the value of the passive safety of Molten Salt Reactors (MSRs). The costs of todays nuclear power is approximately 10X that of the 1960s (corrected for inflation). Regulatory Compliance is a big reason why. It could be argued that regulatory compliance is the sole reason why. Today’s Light Water Reactors (LWRs) are safe, but that safety comes with huge costs due to systems and testing to ensure that safety (as per the regulations). The big accident worry of an LWR is the “Loss of Coolant Accident” (LOCA). Water does double duty in an LWR. It is the coolant and the moderator. It is also under pressure (about 100+ atmospheres) and heated to relatively high temperatures (~300 C). If there is any breach in the cooling system, the water will escape, flash to steam and the core, which is expected to be under water, will no longer be under water. Fission will stop, but the decay heat will remain. With no water flowing through the core, the core will melt. This is a meltdown. This will release the highly radioactive fission products. This is a bad accident. There are systems in place to make sure this doesn’t happen. Pumps to move water onto the core. Backups to these pumps. A containment building large enough to capture all the steam that would be produce if the cooling system was breached. Diesel Generators to power the pumps if there is a loss of Grid power. Batteries to power the pumps if the Diesel Generators Fail. Instrumentation to monitor all these systems, and paper trails of documentation to record and communicate everything that ever happens to the authorities. All of these systems dominate the costs of the power plant. Now, compare that with an MSR. A “meltdown” cannot happen! The core is already in a molten state. The analog would be a “boil over”. But Molten Salts do not boil until extremely high temperatures (1200 C). There is no water under pressure to flash to steam in the MSR. The pressure of the core is essentially at atmospheric pressure (plus some pump pressure), nothing at 100+ atmospheres. If the reactor core is breached, it will leak salt that will solidify. The system drains into drain tanks where fission stops, but decay heat continues. However the salt can tolerate much higher temperatures than water, particularly at atmospheric pressure. So, the salt will be able to passively cool in the drain tank. No Herculean effort to keep water on the core and circulating is required. A containment building could be made MUCH smaller (and cheaper). The bottom line is that the cost of any Nuclear Power generating system is very much driven by the INHERENT safety aspects of the reactor design. MSRs are MUCH safer by INHERENT design. If we had NRC regulations in place for MSRs that are much easier (lower cost) to comply with (because these regulations efficiently reflect the MSRs inherent safety advantages) MSRs could be constructed and operated at a much lower cost. The 10X cost increase that has occurred over the years for LWRs could be reduced or eliminated with MSRs. MSRs might even be able to compete with $11 per barrel oil! If energy was this low cost to produce, we can produce MUCH more energy! With energy this abundant we can solve many of the worlds resource limitation problems! The potential advantages of MSRs are stunningly HUGE!

I needed this balanced, well-informed presentation. My sincere thanks.

Whish I had a lecturer as good as you when I was at uni. Love your videos keep them coming.

Great to see a balanced view on thorium. So much of it is overhyped.

Please consider adding to your WHY BOTHER the potential benefits of MSR: 1, Safety associated with low pressure salt coolant 2. Much longer thermal response and the potential for dumping the fuel into a safe configuration. I was involved in the TMI accident from the day it happened to cleanup and hope you guys give the safety advantages as serious look. 3. The tremendous potential benefit of higher temperatures- greater efficiency, use of downstream process - desalination desalination, drying processes, bottoming cycles... There are still questions, but I hope you seriously look at what Weinberg and those guys pulled out of the nuclear plane. We used the hanger for LOFT. But I think there's the potential for more than that!!

You are such a great teacher , sir

That was informative and complete! it's so hard to find anything on Thorium that doesn't toot the horn of one position and completely ignore the other side. This may be the only video I've watched that explains the pros of Thorium without saying it's *impossible* to get bomb-grade fissile fuel out of it.

I really appreciate quality presentations like this, thank you. Difficult material explained well about a topic like this can help open minds. I think Thorium reactors are certainly worth exploring as experiments in some level even if we don't end up scaling production. What we could learn may well be worth the cost even if Thorium itself remains a novelty. I would love a video going into more detail about the economics of reactor construction/operation and ways we could improve costs without taking short cuts on safety (maybe producing more, smaller megawatt reactors and thus scaling production?). Nuclear power will be needed more than ever if we are serious about environmental progress (renewables don't strike me as a serious effort).

Thank you for these videos. I've been binge-watching them and making notes. I had forgot how much I enjoyed physics back in the 90's. You've actually made me look for enrolling to some university courses just so I can learn more.

Seconding the comment below. The compelling economics come from using molten salt. This is done at ATM pressure range (Low pressure, just enough to pump the low viscosity fluid around) which means way less steel and concrete and a dramatically smaller foot print. That is big $. Add up the materials & weights / sizes of the systems and you can realize the major impacts (Thorcon does a god job describing this). Also, the most toxic, short-lived radioactive gases that want to escape from a water pressure system, are kept in the molten salt, so it is way safer from an exposure point of view, even above what you said. There are lots of details, but these are the big practical ones. The high cost of regulations & project delays come from the fears of releases, which just have no way to occur in a molten salt system, there is no motive force to spread things all over & it is passively safe. The economic model is different as there is no expensive fuel prep needed as there is with traditional systems, so you don't make money on the fuel per say. Instead, current models make money on the safe removal and future recovery of the remaining unfissioned fuels. Another important aspect is the degree of utilization. In pellet form, you can't go to high conversion, as the gases build up in the pellets and would fracture & release. In a liquid fuel, you just keep reacting until you reach practical limits on other materials, like the carbon moderator. Current modeling work is working out the details of this, confirming it is safe and controllable with the various byproducts that increase over time. But it is true, there is a high sunken cost to developing a new technology & the existing tech companies have NO incentive to do this, as it doesn't help them extend their current asset base, so only makes sense for a new player. I think we will see some commercial reactors by the 2030s. This seems to be where most all the major players are falling out. But, as you say, with $11 -$20/barrel oil, there is NO incentive to do ANY NUCLEAR, unless you do not have your own fossil fuel resources, then you do have a reason - self sufficiency & political stability. The US was willing to take on cost in order to also have nuclear weapons for security reasons.

I appreciate the effort to communicate rational information concerning things nuclear as knowledge reduces the inherent fear of the unknown in the general public. I totally disagree with the conclusion of no economic driver for a new fuel cycle. The advantages of moving from a solid fuel machine like reactor to a process like molten reactor have not been fully explored or discovered. This movement will involve solving a new set of technological problems to fully exploit the new paradigm. Design of molten salt breeders (breeders are the only future that makes sense) for both thorium 232 and uranium 238 should be explored and developed (they already are..Elysium.....Flibe....ect.) while we are at it. The one limiting factor is the amount of U235 (or Pu239 in spent fuel) as everything starts with something fissile to start breeding. The energy density of nuclear is the only thing that makes it economical for solid fuel reactors to operate at 4-5% fuel efficiency to heat conversion. Molten salt reactors are closer to 95% conversion of fuel to energy.......what do you think that does to the economics?

Ideally we would use LFTR reactors to convert spent rods into shorter lived byproducts as well as creating useful isotopes. By continuously separating out various elements and adding other ones to these outer tanks all kinds of isotopes can be made. like Plutonium-238, and terbium-161, lutetium-177, Bismuth 213

I love this chanel. The intro is brief and the information is densely packed.

Well, I suppose I can like it twice then.

This channel is HUGELY underrated. Thanks for sharing your knowledge with us.

well stated and balanced arguments. i also appreciate the economic view. i was unclear about why no full scale thorium reactors in usa, but this helped clear it up. i know now we have an abundance supply of uranium and 60yrs of technical experience working with it. currently we have a world surplus of uranium, unless uranium becomes extremely expensive there is no reason to do this. thanks!

Glad to see you're back!

Extremely interesting, as usual. 👍❤️

why bother? no pressurization, insane thermal stability.

Thank you for producing both the original video and this revised version a well. You produced a good presentation the first time and now with the second version clarified the advantages and disadvantages even more. Nourishing food for thought.

Another use for these is emergency power systems at existing nuclear.

Watching again. Amazing prof.

I hope other technical video makers will watch your videos and learn how it ought to be done. Keep up the good work.

Thanks a lot for the extra effort. This great lecture is worth every second you invest.

Dear Illinois EnergyProf, I was very disappointed after I watched your video on small modular reactors but after watching this video I was so happy that I no longer had to carry that disappointment with me all of the time and now I have a renewed respect for you and your channel. It would seem , however, that this video preceded the modular reactor video, so I neg'd your lecture before I had all of the information that I needed in order to make a reasonable decision. So, I would like to apologize for my rash reaction to your lecture and opinions. I'm so happy that I can watch your videos again without that burning disappointment constantly simmering in the background.. This video was amazing and I rate it as one of the best on youtube!!! Absolutely fantastic and very impressive. Could you get me a pass, (I have no $$ with which to educate myself and other commitments make it an unreachable goal), so I can come and learn everything from you and get a Phd? Thank you!!

Sir: Thanks for putting out this video. I also note there are some extremely well thought out comments that are well worth reading. There certainly do seem to be a lot of advantages to Thorium coupled with the Molten Salt Reactor. Perhaps a safe prediction would be that we will see one built on this Earth in the next 10 - 15 years?

Fantastic lecture as always. Very informative!

Absolutely fabulous video, if only our governments were smart enough to realise that molten salt reactors, DC interstate power lines and flow batteries (hydro), are our way forward too green base load power production, solar is sweet and wind is wonderful, but neither are predictable.

Great video. Thank you!

This is a phenomenal video. Thank you for sharing!

Thank you for re-uploading.

Thanks for the presentation!

Thanks for another great video, Professor!

Great presentation. Thank you.

Absolutely amazing job explaining this. Thanks again for such a wonderful video.

Thanks for fixing the audio sync!

This is my new favorite channel.

Another excellent presentation, thank you

I'm admittedly the worst student quite possibly of all-time and throughout the history of mankind and probably of anykind. I can't stop watching prof Ruzic, seriously. WTF do I know about reactor this, nuclear that, fissionie stuff etc etc but this dude has me exceeding the speed limit home from work so I have a little bit more time at night to watch videos of him doing his damnedest to explain it in a way even I sort of comprehend.......... There's gotta be some kind prize I can nominate him for, right ? Thank you professor Ruzic, I dig. Advanced Degree School of Life, Bachelor's Degree in dropping out & Summa Louder than Others Greatest Papa of All Time at University of the Hard Headed.

Thank you for this succinct explanation, very useful.

However safe you feel light water reactors are, nuclear power has a bad reputation because of radiation releases from light water reactor accidents. A significant portion of the light water reactor cost is due to safety requirements. The restriction of the light water reactor to low temperatures confine their use to generating electricity without the heat applications available to molten salt reactors.

These lectures are great. Easy to understand basics for non-experts to get interested in science and technology. Thanks for sharing. :)

I'm a big fan of the MSR concept. After all, it was what Admiral Westinghouse recommended for large scale nuclear plants back in the '50s. It's just frustrating that it still hasn't really gotten anywhere, but the reasons given at the end of this brilliant lecture tell you why.

Good video, very nicely explained. Thank you,

Thank you for your contribution.

My favorite professor!!

Second thing, he represents what's important for nuclear reactor: Not U238 but U235 It's U235 that's burned up and that's pnly 0.7% of all Uranium available and has only ~700 Mya half-life. Enrichment means that the relation of U238 / U 235 is "enriched" because "Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction.", the PWR/BWR are made to make bombs, that was the idea behind the creation of these reactors and the deployment in the fleet: "run the submarine and create the bomb material", the Nautilus was a proof of concept for this. U238 is being breed to be Pu239 by Neutron capture. Thus the real fuel is not 3 - 4 times less abundant but more like 300 - 400 less abundant. Aside the fact that Thorium is also found in the same mines where rare earth metals - which are e.g. required for semiconductors - are mined in higher concentration and abundance. "The world's present measured resources of uranium (6.1 Mt) in the cost category less than three times present spot prices and used only in conventional reactors, are enough to last for about 90 years." - world-nuclear.org/information-library/nuclear-fuel-cycle/uranium-resources/supply-of-uranium.aspx - en.wikipedia.org/wiki/Occurrence_of_thorium The next is the "tiny amount of waste on comparision", that is 1st of all gas lighting, and 2nd false equivalence falicy: to 1) a) The mining is far more extensive: 100.000's of tons for 1 ton of Uranium, vs. a few 100's tons for Thorium - mining is not CO2 neutral, as well b) The preperation (e.g. making the yellow cake, then making the fuel rods from which requres encasing in highly accurate zirconium alloys - is chemcially and energy wise extremly demading and hence also taxing the CO2 balance. c) the reprocessing treatment of fuel rods - which is what the industry exxentially make all their money with - is extremely elaborate and expensive as one has to handle highly radioactive materials which are essentially disovled into hydrofluoric acid to then be physically separated in those "centrifuges" and then be re-constituted into non liquids to be made into rods again. to 2) The United States has (2021) 93 operating commercial nuclear reactors that produce 2000 Tonnes per year of "spend fuel" - www.eia.gov/energyexplained/nuclear/us-nuclear-industry.php - www.energy.gov/ne/articles/5-fast-facts-about-spent-nuclear-fuel "In LWR, uranium fuel cycle start with 250 tonnes of uranium, 35 tonnes of enriched uranium contain 1.15 tonnes of useful 235U. From this, the waste produced is 35 tonnes of fuel containing 33.4 tonnes of 238U, 0.3 tonnes of 235U, 1 tonne of fission product and 0.3 tonnes of plutonium [Hargraves & Moir 2010]. By contrast, in thorium fuel cycle 1 tonne of thorium [which represents a 1 GW electrical reactor] is used in its entirety and comes out on the end is a tonne of fission products and 0.0001 tonne of plutonium which needs to be stored for a very long time. The fission products produced 83% are stale in only 10 years and 17% in approximately 300 years [Hargraves & Moir 2010; GBCN. Net. 2013]. Figure 1 below showed the comparison between the amounts of raw material needed and waste production for LWR and LFTR [Hargraves & Moir 2010]." - aip.scitation.org/doi/pdf/10.1063/1.4916861 "The volume of waste products from a LFTR is approximately 300 times less than that of a uranium reactor. " - pubs.acs.org/doi/10.1021/es2021318

The only complaint I have is that some of the products of these reactors, as I've read, can be useful in medical applications. As public backlash against light water reactors keeps new ones from being built and old ones getting shut down more and more frequently, even before paying themselves off in some cases, additional income streams will become more valuable for those that remain, or what new reactors are brought on to the market. Additionally, it could almost be the case that they could be paid to burn away the (~90+%?) unburned 'waste' from light water reactors, which mitigates an expense on both the locations that need to find long term storage for this waste and mitigates the expense of the MSR's fuel source. More pedal, less brake I say. But let's be savvy about it.

Thank you Prof., very beneficial lecture

Once again, I love your calm demeanor and “just the facts” wholistic approach to explaining Thorium based reactors to us mere mortals. :)

Very well presented and said. I was a huge LFTR fanboy for years until I started looking deeper into the details. The pragmatist in me led me to these very same conclusions. Thorium will be an extremely viable and cost-effective fuel for nuclear power. Just not now. We need other GenIV reactors and other bridge technologies to carry the load until we can bring the cost-benefit of thorium into a financially practical option. Until we reach the holy grail of fusion - how many decades away?? - thorium will carry us there, no matter how long that takes. Eventually.

great video

The main reason we should "start over" with thorium for me personally, is because of how the world works, or rather how people work. When we developed uranium reactors we ran into a host of problems, and we solved them one by one until we finally could make a working reactor. Once we got a working reactor development slowed down, now it was new problems which spurred us on. If we start with developing a thorium reactor we will run into new problems that we have to solve, some of those solutions that we find might make reactors safer, more efficient and leave us with less nuclear waste. Which we then could use in normal uranium reactors too. Even better yet now we could use both kinds of reactors depending on what is more economically efficient at that place.

Wow such an awesome presentation. Such a good solution for humanity on so many levels...

The future of nuclear energy is in serious doubt. It is not cost competitive with gas, coal, oil, or even solar. Conventional light water reactors have significant public opposition. First is safety and second is long term handling of radioactive waste products. Both thorium and U238 breeder reactors offer solutions to these issues. In particular, a molten salt U238 fast breeder, (e.g.Elysium industries) can use existing nuclear waste as its fuel (no mining required), reduce the waste storage time by a factor of 1000 (and the quantity of waste by a fact of 25), and be passively safe. Only with a new system does nuclear energy have a future. Otherwise, the existing plants will be allowed to be shut down, and few new ones will be built. None the less, I agree with the prof, the thorium cycle is not needed at this time. But developing a breeder is the future for nuclear power - if there is going to be one.

I enjoy your clear explanations. I am a fan of the MSR reactor theory but for many of the reason you point out they are not a reality. In researching the slow realization of functional MSRs it becomes apparent that one of the real big impediments to actualization is the materials science needed to develop process and reactor materials that can be manufactured and incorporated into these systems that can withstand high temperature salt corrosion. We have been playing with this technology since WWII. There now seems to be some concerted efforts to get a working model. However there are so many “competing designs” globally I question the lack of cooperation and collaboration regardless of politics and political ideology interfering in true efforts to develop the solution rather than a win!

"when oil is 14 per dollar nothing is competitive" lol now it has a literal negative price.

Thorium is already in a lot of rare earth ores, so we already have it coming up.

You have not mentioned the association of thorium with rare earth elements. One of the biggest inhibitions to production of lanthanides is that they all have byproduct thorium. Developing technology to handle thorium - and a place to put lanthanide mining "waste" would be a good thing, overall.

Great presentation! Bravo professor! Thank you from humanity! :-)

i love ur videos. Thks prof

Amazing

We know very well how to make vacuum tubes, they work well and meet our needs, and we've solved a lot of problems with them. Clearly, while it would be nice to explore this "transistor" thing, it may become interesting some 100s of years in the distant future.

Thanks for all your videos, I use them in the college chemistry classes I teach.

Separation of the uranium and thorium is a bit of a gonad pain in a production reactor. Doable, but one can use nitric acid at specific molar levels or a few other tricks with the fluoride salt, but either way leaves one with a scalability issue and rather unpleasant acids in something that's radioactively and thermally hotter than a two dollar pistol. Overcome throughput at creation level meeting separation level safely, we're cooking with gas. While you're at it, try to figure out how to do it under microgravity, we'll be cruising the solar system in style! As for nuclear weapons, spot on. The only thing that's really stopped nuclear weapons usage is a surprising burst of sanity in our species, well, that and expense. The rest of your points, I do agree with. And we can add standard fission waste into the mixture and dispose of it safely. Of course, we have fusion power right around the corner. I hear about that, after a bit of rinsing off and repeating every decade. Like a broken record. Whoops, I just dated myself. That's OK, I'll even locate myself somewhat. I miss seeing TMI's cooling plume out of my window, was great for navigation. BTW, any ideas on expended fuel reprocessing?

I was expecting a wild George Lucas to wander into frame when molten salt reactor was mentioned

When can we expect a lecture on Gen V, VHTR (Very High Temperature gas-cooled Reactor) AKA: Waterless Pebble Bed Reactor. It is my understanding that unlike modern traditional Nuclear power generation schemes, which require a large local water source for cooling, VHTR has all of the benefits of Thorium Molten Salt reactors you mentioned, is small and potentially very cheap, but due to gas cooling, can be located in any location as no water source is needed.

Thanks, I’ve become a fan of these videos recently. Informative and entertaining. The fact that this particular vid on thorium and MSR is from the not too distant past, I’m wondering if recent events have altered your position on the economic viability. In particular China has leveraged enormous amounts of financial and technical resources to revive the thorium MSR concept first proposed by ORNL. Current US advocates Kirk Sorenson of Flibe Energy and ThorCon CEO Lars Jorgenson would probably agree that without the financial and political advantages of China, the near term market for small companies like theirs will rely on their ability to deliver an economically competitive alternative to fossil fuels. Recently they have both given presentations that targets delivery of small modular reactors at a price point competitive with coal. …and China is supposedly very close to completion of a full scale MSR prototype. Has there been any new discoveries from any of the noted thorium proponents to suggest they are moving the technology towards fruition?

Excellent points for and against. I would prefer to see more investment personally.

ThorCon is making a test Thorium Power Plant that can be made and installed in 2 years instead of the 6 years it takes for a Uranium Power Plant. They will be testing for several years yet, but keep an eye out.

Renewable energy just WON'T cut it. Not if we're trying to replace oil with it.

I'd love to see him and Kirk Sorensen discuss thorium.

I like the idea of the kidney separating the actinides and then cleaning out the fission products as an inline process, also breading Thorium in an outer blanket from the core. Although burning up the stockpiles of the higher actinide waste would be a better starting place. I don't think the old guys want to learn the chemistry needed to do this, so I understand the bias displayed. I can't bring myself to write my elected officials in favor of PWR/LWR type reactors, not after learning about MSR/LFTR options. Frankly, there is interest. Unfortunately, economic inertia can not read the room, but unlike actual inertia, it can be starved to reduce its effective mass. I want efficient, clean power that does not cause stockpiles that will become targets in the future.

. A good quick lesson / Thanks

Very good overview. One thing we need to understand about the economics: Gen 4 nuclear would enable the best chance for civilization to withstand a medium size asteroid or a year 536 super volcano event where we could have darkened skies for a decade. A world superconducting power grid that would enable us to keep the lights on under these conditions may be above the level of economics calculations, if it is of such existential value that it would be a key to survival.

Nice lecture professor thanks. Its a shame that a Channel like this has so few subscribers while some kid playing some stupid silly game has 1 millions views. Keep the good work

A long half life means slow decay. Hence why uranium 238, with it's 4.2 billion year half life, can be bare handed completely safely. U238 is routinely used as a radiation shield in sensitive radiation measuring instruments. It's also widely used as armour plating for military combat vehicles due to it's density and ductile nature. Presidential and ministerial reinforced limousines are also built with U238 to stop projectiles.

Thanks for explaining how to get U233 without U232--most videos miss this point! (10:50) In 1998, India's Shakti 2 created a 0.2kt nuclear bomb using U-233. This is small enough to be a fizzle, but large enough to show it can be done. India experimented with Thorium because it has to import Uranium.

Thank-you for this education. I was really scratching my head about why we didn't go the route of thorium.It's unfortunate that countries went with the pathways that make bombs, and lots of them. But from the other videos, it is clear that nuclear energy, in the U.S. is much safer than I thought. At least for the newer plants.

I suppose it doesn't really go on this topic, but the biggest reason to use thorium is economical. Thorium is always found is deposits of rare earth elements, which makes sense, since thorium is the earliest stable actinide, and rare earth elements are their periodic neighbors, the lanthanides. Currently, thorium, a naturally occurring element, is treated as a nuclear waste, and mining companies that find it have to just bury it over. If we just change the classification of how we can use thorium, we (I mean humans, outside the PRC) could make rare earth mining less rare. Even if we don't wind up using it for fuel, just being permitted to collect the ore and sequester it would easily triple the available worldwide supply of neodymium (ironically making wind turbines and fusion confinement magnets cheaper to make). Since thorium is radioactive as an alpha emitter, its radiation is literally shieldable by a piece of paper. Also, thorium oxide is highly insoluble in water, unlike uranium oxide, so get worries about it getting into ground water. Even better, decaying thorium is not only the source for the Earth's internal heat (along with uranium), but being an alpha emitter means that it's a source of helium. Just being able to treat thorium ore with the nuclear care given to, say, granite, would help global production of rare earth elements, which could pay for the research to get both thorium fuel and MSRs going. Because we have such a long history with regards to uranium research, Kirk Sorensen has already been quoted to say in talks that if you aren't planning to specifically build a thermal neutron breeder reactor, you might as well stick with uranium

Thanks very much Professor Ruzic - I was just thinking as space stations develop and get larger a lifter reactor might be ideal for a space environment.

What a BEAUTIFUL explanation with the all-important economic context. Perhaps for a different video - one of the aspects that may make this more attractive sooner than later, is the concept championed by Bill Gates et. al, the NATRIUM system, which is paired with a molten salt storage reservoir (only a slight variation on your diagram) and sized to match "retiring" coal plants, such that the reactor can run at its most efficient 100%, while a separate operation will pull heat from the reservoir to produce steam for the existing power infrastructure taken over from the now formerly coal-fired plant. This combination effectively allows the plant to load-follow, thus better matching the grid for the addition of solar and wind with all their inherent variability.

Hi energyProf! I read an article about high-entropy alloys being used in reactors to limit radioactive damage to the steel. Do you think it has promise?

All the genius comments from the last video are gone now 😱

Jan Michael Vincent post Airwolf days 😏. Cool vid, thanks

I’ve watched every one of your videos. Thank you. Do I get a minor in nuclear physics now?

Regarding the comment that we haven’t had experience with Thorium based reactors and there would be a “learning curve”... “After World War II, uranium-based nuclear reactors were built to produce electricity. These were similar to the reactor designs that produced material for nuclear weapons. During that period, the government of the United States also built an experimental molten salt reactor using U-233 fuel, the fissile material created by bombarding thorium with neutrons. The MSRE reactor, built at Oak Ridge National Laboratory, operated critical for roughly 15,000 hours from 1965 to 1969. In 1968, Nobel laureate and discoverer of plutonium, Glenn Seaborg, publicly announced to the Atomic Energy Commission, of which he was chairman, that the thorium-based reactor had been successfully developed and tested.” Note, the 1960’s.

It's like deja vu all over again.

Its the holy grail of nuclear reactor technology.