The problem with nuclear energy in the US, is with the 99% of people totally ignorant on the subject, but the same 99% think they know everything on the subject. Try having a logical discussion with most people on the use of nuclear power to solve the energy problem (and CO2 problem) and they start talking loudly, waving their arms frantically and shouting "Three Mile, Fukushima, Chernobyl". No matter how safe, clean, and efficient nuclear reactors can be made, we will always be confronted by the 99% , and that includes politicians. Your video here was fantastic, but you are preaching to the choir. How do we chip away at the 99% ignorance factor when millions of smart phones blast electromagnetic misinformation faster than they do truth and logic ???
Build a pilot plant, like they did at Oak Ridge in the 1960s. Use public funds, like they did with PWRs. Re-structure the regulations to suit a low pressure, thermally negative co efficient, passively safe design, then make all that IP publicly available, as was done in the 60s. No private company will take on the total FINANCIAL risk. No regulator will trust a private company to demonstrate the framework needed to build new regulations. No company will share its hard won IP with the regulator and others. Therefore, make it a national project, like the moon shot, like the Manhatten project, like the national highway system. Then you will get the benefits of a national project, with transparent research and regs, and build public confidence in the technology. Some things are better done by the whole of a nation in the open, than by the private sector. The greatest leaps in public knowledge and technical advances were funded by the public... Then the private sector came in and built on that knowledge. Seriously... The Dr.
Making that a publicly funded project is good in theory, but it's probably not going to happen because politicians are ignorant about nuclear power and cower to the ignorant masses. It will ultimately take someone like Elon to make it happen and probably not in the USA.
At oak Ridge when they wanted to go home for the weekend they would just dump the reactor into it's holding tank and Monday morning they use electrical heaters, pump it back in and fire it up again. You don't get a fission in the tank because it is a flat sheet, not in a form that will keep fissioning.
Thankyou, CanDu (Canadian deuterium moderated reactor) one of the best Gen 3 reactor designs aimed at addressing safety, fuel cost and non-proliferation. It can also be fuelled with a U-Th mix. The plants are costly to build but have had a good operational record and many lifetime benefits.
There are also molten salt reactor designs where the load following feature is achieved by another process. If the temperature of the salt increases it will expand, this will cause the density of the fuel to decrease, causing the fission reactions to go down, reducing the temperature. If there is a lot of demand of the electricity grid, more heat is extracted from the salt, causing the temperature to go down and the fission to increase.
Ed Pheil (Elysium MCSFRs) talks a lot about this on TH-cam. His fast reactors use this principle. Completely and easily scalable, and as you say naturally load following. Very simple - no moderator, cheap, clean, burn nuclear waste as fuel.
@@bhakta_joe It is technically called "Negative Temperature Coefficient of Reactivity". Many advanced reactors are designed so that this property is much higher than in current thermal reactors. It was tested in EBR-II/Integral Fast Reactor in the mid-80s by shutting down all cooling and safety systems at full power. The core heated up and just as predicted, it reached a plateau lower than the boiling point of the coolant (sodium) and then slowed to idle with zero intervention or moving parts based solely on physics with no damage to the core. There are multiple different properties that produce feedback loops, Temperature Coefficient of Reactivity is only one of them.
@@richardbaird1452 Well said. However, the load following idea is relatively slow compared to variations in demand. Hence peaking plants. This function can better be handled by renewables and storage systems from batteries to pumped hydro. Short duration and rapid response to grid variations. Best of both worlds and no carbon!
@@drstrangelove296 Not sure which comment you are replying to, as I didn't mention peaker functionality in this part of the thread. Gas peaker plants provide two different functions on many grids. One for rapid short duration stabilization which you point out and yes, batteries are the fastest way to do that stabilization function as it is essentially instant but VERY expensive for large capacities. Another is for more coarse grain fluctuations such as load peaks in for example morning/evening, where the quantity of storage required can make batteries cost prohibitive. Stored solar thermal can ramp up/down by 10% per minute, which is what MOLTEX's and Natrium's systems are based on. That is plenty fast enough for the second function and might even be enough for the first most of the time. Different places in the world (or even within large countries) can have drastically different requirements vs resources available, so having a multitude of no carbon options is a good thing. It allows designers/operators to choose based on the best solution for the specific situation, which for some places might be batteries/pumped solar and others might be a heat storage scheme like Natrium/MOLTEX have proposed. Having multiple options is truly the best of both worlds. Lacking a solution for a specific situation is not.
Fast MS reactors create fewer neutron absorptions (and therefore fissions) per amount of fuel, so they compensate for this by always having a larger amount of fuel in the reactor. They are load following and can still have quite low power, and heat exchanger capacity, but always the same (critical) size reactor vessel.
Around 13:00, this gets really confused, and confusing. A fast neutron reactor can fission some useful amount of U-238, because the neutrons are fast. But the CANDU reactor uses THERMAL neutrons, because of its (BTW very expensive) heavy water moderation. That's an ENTIRELY different thing. It can use un-enriched uranium, 99.3% U-238. But that doesn't mean it's making any effective use of U-238 as a fuel. Clear as mud, this discussion at this point.
Neither fission a useful amount of U238 (near if not zero). Both can convert it to Pu239 and fission that. The presenter was confused on a lot of items IMO. Several times he mentioned modertor not being as important in fast reactors...there is NO moderator in a fast reactor, so it isn't just "not as important" it is absent. He also lumped all solid fuels together, however the negatives he mentions mostly don't apply to metallic solid fuel, only to oxide solid fuel.
The hot side of your heat pump isn't the sodium chloride temperature. You would use a second loop of water to drive a turbine. The cold side is approximately the temperature of the body of water you use to dump the heat into. The hit side is the temp of your water boiler so maybe around 300 centigrade for typical steam turbine or maybe 400 centigrade for a supercritical turbine
Use the same molten salt for both the primary (fuel) loop and the secondary loop, to keep the temperature high and pressure low, with a slightly higher pressure in the 2ndary loop to prevent radioactive leakage into the 2ndary, then exchange down to steam or whatever for turbines.
@@red-baitingswine8816 Carbon Dioxide gas turbines can be very efficient, smaller, and don't have the phase change issues that water at high pressure has.
@@drstrangelove296 Sounds good. Some say that for MCSFR (and FLiBe?), since fuel is so cheap (or you get paid to burn waste!), whichever turbine is overall cheaper to operate is best.
The nuclear presentation was excellent thank you. However, the waste disposal in deep bores is perhaps not as simple as you seem to suggest. This might be a subject for some future presentation perhaps?
If you had read one sentence further on the first Wikipedia page you'd have come across the sentence, "These nuclear materials have other categorizations based on their purity," and that would have linked you to the "Special nuclear material" page that may have been helpful also.
Future self: Developing country purchases Thorium reactor, subs out Thorium for U238. Processing plant now processes out Plutonium, makes bombs. Value stream for manufacturers is patents, plant building and export. Developing countries need energy, their leaders want bombs. What is there to prevent this scenario?
@@shawnnoyes4620MSRE used something similar, Bechtel says it was there most challenging cleanup, still underway I believe. Politicians want bombs and that is where the government money comes from.
@@rogermorey You will not do anything, unless it is a military intervention in the country, which will lead to the development of atomic weapons by other countries, i.e. escalation. It just depends on the promise of the country itself, for example, like South Korea.
Some issues that might be of concern for deep bore nuclear waste disposal might be cooling, accumulation of flammable gases and risk of explosion, accessibility should there be a problem etc. What do you think?
I think in a fast reactor you could just let Pa 233 sit in the reactor vessel until it beta decays, then fissions, as long as the net fissions from total fissile material are enough. (?)
CO2 is gaseous at room temperature. Imagine the pressure at 100°, 200°, 1300°C... At the temperatures desired to maximize carnot efficiency, your supercritical CO2 is effectively a bomb waiting to go off. The moment that Murphy's law strikes, you have a nuclear incident.
Yes but what happens to the water that leaks into the deep bores it becomes contaminated. The deep bores fill up until they join the water table and then!!!!??? what?
Can Elysium's MCSFR burn natural Uranium (U238) or Th232, by just leaving them in the reactor vessel until they breed, then fission, and just regularly adding more U238/Th232?
In a fast breeder reactor wouldn't most of the actinides eventually break down inside the reactor after a long period? Like 20 years? Or would they negatively affect the fissioning process too much?
19:00 Woh, was this presentation in **1985**?! If so, I must say, the video quality is pretty good. But I have to question its relevance now, almost 40 years later.. 31:00 OK, around now it's obvious this must be much more recent. IAC he's been talking about thorium all along, so clearly this is recent.
52:50: What processes can be switched off and on cheaply to use excess nuclear power? How about desalination? Manufacturing hydrocarbons from CO2 and water? . Since some MSRs are inherently load following, could the electricity generation apparatus (exchangers, turbines, etc.) be governed, and the change in exchanger temperatures be conducted back to the reactor, to slow/speed the nuclear reaction?
Most industrial processes are designed to be efficiently run at a constant pace so switching them on/off is usually undesirable. Inherent load following via Negative Temperature Coefficient of Reactivity (NTCR) is not a great idea IMO, because the temperature swings will have an effect on the metal. Just as you can only bend a paperclip so many times before it breaks, the same applies to reactor vessels, piping, heat exchanges, etc... with regard to temperature swings. The more the temperature swings or the more times it swings, the lower the lifespan of those components, or the more expensive they are to design/build to accommodate. Very high NTCR as demonstrated in the solid metallic fueled EBR-II and adopted by most Gen IV designs including most MSRs is a great feature, but mostly from a safety standpoint. Relying on it as the primary reactor control function is a bit dicey unless you intend to replace the entire component regularly, which some MSR designs propose (again, not a great idea as that significantly increases the mass of activated materials that need to be dealt with). IMO, a better approach is to store the generated heat and use it as needed. That way the reactor always run full out at a constant temperature, but it is decoupled from the final use of the energy and all the components that constantly vary in temperature (Steam generators, turbines, etc...) are outside the nuclear island and can be easily repaired/replaced since they are not activated by neutron bombardment.
Couldn't a fast MSR (e.g. MCSFR) with an initial supply of fissile material, run on natural U (ie. U238) as a breeder reactor, just leaving everything in the reactor and adding U238, for, like, 50 years?
Constructive Criticism; Please deal better with your self corrections. Protons, I mean Neutrons, I mean 238, no I mean 235?? The way you left both parts hanging left Me thinking, so wait; is he talking about 238 or 235... I used to understand the difference, now I am confused. It makes what you are saying very confusing, especially if you do not pause after a correction. If you are talking at full speed, and make a correction, you should pause slightly to allow for the listener to catch up and after digesting the correction (after you have corrected yourself) or possibly you could immediately present an example which is particularly important when trying to grasp this stuff. But really, you should start again; you have a camera. If you say something wrong, stop the camera and start again, don't just say "I mean" and then keep going, but offer half a sentence that only makes sense if the listener knew exactly what you were saying. It actually sounded like you were answering a question for a test, rather than explaining to an arbitrary listener. Thanks
If a phrase like "the Early Universe" is relevant to the design and function of a safe Reactor, (maybe the Equivalence Principle applies because a Stopwatch must be used to measure elapsed time), then the reasoning.., Mach's Principle and such like, ..needs to be demonstrated by application to functional standards, (ie in particular, we all want to know why a Big Bang reasoning is relevant?). I'm attempting to make an Amateur Metastudy and plead for actual Sciencing Re-search to validate the theory or theology of what is REAL Actuality, save the planet, please. Otherwise, this is another great lecture when on topic.
10:05 "All the deuterium that we have was created in the first three minutes..." Not exactly true because deuterium is created in a light water reactor. You said that 2 minutes ago. ;-)
Wikipedia tells me that after a week the spent fuel produces 0.2% of the power it did in the reactor. That's still a lot of heat in many contexts, but it is probably not worth the trouble to design a capturing mechanism in order to increase power plant efficiency by 0.2%. So, using the fuel on site isn't worth the trouble. (The decay heat is ~6% the moment the reactor shuts down, so presumably it is capturing that decay heat when it is actually running.) This leaves the possibility of using the fuel in some application away from the power plant (e.g. in some sort of district heating setup). I can see two problems with this. First, the heat that you want to harvest from the fuel will make the fuel difficult to transport. Second is that each of these use locations now has the potential to have a spent fuel meltdown if cooling fails (similar to Fukushima). Much better to keep the waste in power plants that have to prepare for those kinds of eventualities anyway. From what I understand, there is TRISO fuel which can withstand much higher temperatures without melting and releasing vaporised fission products (to the point it can reject enough heat directly to the air to prevent melting). But the point of TRISO fuel (which is more expensive than other forms) is to be able to deploy an entire (small) reactor for your use case in the first place. Strontium 90 and Caesium 137 could be extracted from the spent fuel after a few years and used for some heating purpose after the hottest fission products decay away (perhaps some kind of Stirling Engine). However, this has to be balanced against the risk of loosing track of the material. There have been a couple incidents of people dying from "orphaned" radioactive sources for medical purposes. Almost by definition, the decay heat becomes more valuable the further you are from the power plant that produced the fission products in the first place. However, that also increases the risk of accidental exposure.
42:50: Both fast (Elysium, Ed Pheil) and slow (Thorcon) MS reactors can do this, and use all of the contaminated fuel (including, for Elysium's reactors, weapons grade Plutonium and depleted Uranium) to around 100%, since the molten salt (unlike in solid fuel reactors) continuously recycles the fissionable materials, and fission products and transuranics can be removed easily, in concentrated form, when necessary. Check these sources out on TH-cam! The Thorium fuel cycle is somewhat more complex and requires more R&D, but also works quite well.
With a fast reactor, can't the transuranics just be left in the reactor until they eventually absorb neutrons and beta decay into Pu239? How could a U isotope tbat's neither fertile nor fissile be radioactive?
If the neutron energy is high enough, then most TRUs are directly fissionable in a fast spectrum. In the Integral Fast Reactor/EBR-II, all the TRUs including the higher actinides were recycled through the reactor and most were "burnt" directly rather than decaying to Pu first as that takes too long to happen due to extremely long half-lives. That said the concentration needs to be managed so the reactivity of the fuel isn't changed too much. An isotopes doesn't need to be fertile or fissile to be radioactive. Cs137 is highly radioactive, but neither fertile nor fissile. You are confusing two different things I think. Radioactivity has to do with half-life of the isotopes and it's descendants, not whether it is fertile/fissile.
@@richardbaird1452 . Once a fast MSR gets going, is it feasible to fuel it with unenriched Uranium, or some combination of that with nuclear waste or weapons-grade Plutonium, etc.?
Ed Pheil says gas turbines would work fine, and are more efficient than steam, but are more expensive, therefore not useful for MCSFR, for which fuel costs are negative when burning nuc waste.
Cheap, clean, simple, and safe compared to solid fuel PWRs. But non- breeder fast MSRs can also just burn every kind nuclear waste as fuel, and at the very least 20 times as efficient as solid fuel reactors.
@@red-baitingswine8816 The Presenter needs to differentiate between soild fuel types. What is said in the vid applies to solid "oxide" fuels, but mostly not to solid "metallic" fuels.
@@richardbaird1452 I had no idea. I read a little on metallic fuel rods. How do they compare with Ed Pheil's MCSFR's? Japan has a process to convert Oxide wastes to Chlorides, and his MSR's use all previously used materials. From what I read metallic fuel rod utilization is 20% or less.
@@red-baitingswine8816 Enrichment of metallic fuel is typically 20%, but that is very different than utilization within an entire system. In both cases you need to do some fuel conditioning/reprocessing to get the utilization numbers up high. For MSR this can be done online or offline. For metallic fuels they dissolve them in salts by applying electrochemical separation techniques (similar to electroplating) not too different than fuel salt conditioning used in MSRs. The FPs remain in the salt and the plated out metallic TRU fuel mixture is re-melted, adjusted for enrichment and cast into new fuel pins and run through the reactor again. Neither is fully developed, however the metallic fuel route has had long run prototype (30 years) in the form of ANL's EBR-II/Integral Fast Reactor. Most of the research on non-aqueous fuel reprocessing was done as part of the IFR. Both Japan and South Korea's non-aqueous programs were based on IFR research. The ORNL MSR prototype only ran for a few years, so is far less mature tech at this point and we haven't seen another MSR since until China's recent small engineering test reactor. Since the reprocessing techniques are very similar, so is the overall fuel utilization and much shorter radio toxicity of the waste streams.
Here's an error. If you build a molten salt reactor, you can store molten salt and use it on demand. That means you can store vast quantities of power as well as use coal and better than natural gas. So no, you don't just turn on a nuclear reactor and use the power as you go.
Not that a MSR shouldn't be connected to a TES or anything, as I can only assume running the fuel salt at a steady state will be desirable. However wouldn't a fuel salts burn-up (heat generation) depend on flow rate across the moderator (up to an extent). Couldn't you simply run a VFD, and just forget about using TES for load following renewables?
@@mr_happygolucky7095 Just remember, MSRs will have limited application due to their excessive cost. Solar and wind will smoke them as their price continues to drop. Then again, you still have to have baseline power. Geothermal will be the only competition to MSRs.
Very good talk, but i would have like to have the issues with reprocessing mentioned and i don't mean proliferation. The problem right now is that reprocessing turned out to be a very dirty business. In fact the chemical reprocessing releases more than two orders of magnitude of radiation more in the environment than the current light water reactors, so it smears the nuclear waste around the environment creating more trouble than they are use. Will pyroprocessing really solve this terrible track record of purex reprocessing?
This is so interesting! Thank you. I've also watched the MIT nuclear course and Scott Manly's, and this is very engaging 😀
My favorite non-fiction is Atomic Accidents by James Mahaffey. Great book I always recommend.
"I don't know about Cannotdo Reactors". We have one of those here in Austria.
The problem with nuclear energy in the US, is with the 99% of people totally ignorant on the subject, but the same 99% think they know everything on the subject. Try having a logical discussion with most people on the use of nuclear power to solve the energy problem (and CO2 problem) and they start talking loudly, waving their arms frantically and shouting "Three Mile, Fukushima, Chernobyl". No matter how safe, clean, and efficient nuclear reactors can be made, we will always be confronted by the 99% , and that includes politicians. Your video here was fantastic, but you are preaching to the choir. How do we chip away at the 99% ignorance factor when millions of smart phones blast electromagnetic misinformation faster than they do truth and logic ???
Build a pilot plant, like they did at Oak Ridge in the 1960s. Use public funds, like they did with PWRs. Re-structure the regulations to suit a low pressure, thermally negative co efficient, passively safe design, then make all that IP publicly available, as was done in the 60s. No private company will take on the total FINANCIAL risk. No regulator will trust a private company to demonstrate the framework needed to build new regulations. No company will share its hard won IP with the regulator and others. Therefore, make it a national project, like the moon shot, like the Manhatten project, like the national highway system. Then you will get the benefits of a national project, with transparent research and regs, and build public confidence in the technology. Some things are better done by the whole of a nation in the open, than by the private sector. The greatest leaps in public knowledge and technical advances were funded by the public... Then the private sector came in and built on that knowledge. Seriously... The Dr.
Making that a publicly funded project is good in theory, but it's probably not going to happen because politicians are ignorant about nuclear power and cower to the ignorant masses. It will ultimately take someone like Elon to make it happen and probably not in the USA.
At oak Ridge when they wanted to go home for the weekend they would just dump the reactor into it's holding tank and Monday morning they use electrical heaters, pump it back in and fire it up again. You don't get a fission in the tank because it is a flat sheet, not in a form that will keep fissioning.
Thanks for the depth
I truely believe nuclear is the future
So many solutions
Thankyou, CanDu (Canadian deuterium moderated reactor) one of the best Gen 3 reactor designs aimed at addressing safety, fuel cost and non-proliferation. It can also be fuelled with a U-Th mix.
The plants are costly to build but have had a good operational record and many lifetime benefits.
There are also molten salt reactor designs where the load following feature is achieved by another process. If the temperature of the salt increases it will expand, this will cause the density of the fuel to decrease, causing the fission reactions to go down, reducing the temperature.
If there is a lot of demand of the electricity grid, more heat is extracted from the salt, causing the temperature to go down and the fission to increase.
Ed Pheil (Elysium MCSFRs) talks a lot about this on TH-cam. His fast reactors use this principle. Completely and easily scalable, and as you say naturally load following. Very simple - no moderator, cheap, clean, burn nuclear waste as fuel.
@@bhakta_joe It is technically called "Negative Temperature Coefficient of Reactivity". Many advanced reactors are designed so that this property is much higher than in current thermal reactors. It was tested in EBR-II/Integral Fast Reactor in the mid-80s by shutting down all cooling and safety systems at full power. The core heated up and just as predicted, it reached a plateau lower than the boiling point of the coolant (sodium) and then slowed to idle with zero intervention or moving parts based solely on physics with no damage to the core.
There are multiple different properties that produce feedback loops, Temperature Coefficient of Reactivity is only one of them.
@@richardbaird1452 Well said. However, the load following idea is relatively slow compared to variations in demand. Hence peaking plants. This function can better be handled by renewables and storage systems from batteries to pumped hydro. Short duration and rapid response to grid variations. Best of both worlds and no carbon!
@@drstrangelove296 Not sure which comment you are replying to, as I didn't mention peaker functionality in this part of the thread. Gas peaker plants provide two different functions on many grids. One for rapid short duration stabilization which you point out and yes, batteries are the fastest way to do that stabilization function as it is essentially instant but VERY expensive for large capacities. Another is for more coarse grain fluctuations such as load peaks in for example morning/evening, where the quantity of storage required can make batteries cost prohibitive. Stored solar thermal can ramp up/down by 10% per minute, which is what MOLTEX's and Natrium's systems are based on. That is plenty fast enough for the second function and might even be enough for the first most of the time.
Different places in the world (or even within large countries) can have drastically different requirements vs resources available, so having a multitude of no carbon options is a good thing. It allows designers/operators to choose based on the best solution for the specific situation, which for some places might be batteries/pumped solar and others might be a heat storage scheme like Natrium/MOLTEX have proposed. Having multiple options is truly the best of both worlds. Lacking a solution for a specific situation is not.
Fast MS reactors create fewer neutron absorptions (and therefore fissions) per amount of fuel, so they compensate for this by always having a larger amount of fuel in the reactor. They are load following and can still have quite low power, and heat exchanger capacity, but always the same (critical) size reactor vessel.
Around 13:00, this gets really confused, and confusing. A fast neutron reactor can fission some useful amount of U-238, because the neutrons are fast. But the CANDU reactor uses THERMAL neutrons, because of its (BTW very expensive) heavy water moderation. That's an ENTIRELY different thing. It can use un-enriched uranium, 99.3% U-238. But that doesn't mean it's making any effective use of U-238 as a fuel. Clear as mud, this discussion at this point.
Neither fission a useful amount of U238 (near if not zero). Both can convert it to Pu239 and fission that. The presenter was confused on a lot of items IMO. Several times he mentioned modertor not being as important in fast reactors...there is NO moderator in a fast reactor, so it isn't just "not as important" it is absent. He also lumped all solid fuels together, however the negatives he mentions mostly don't apply to metallic solid fuel, only to oxide solid fuel.
The hot side of your heat pump isn't the sodium chloride temperature. You would use a second loop of water to drive a turbine. The cold side is approximately the temperature of the body of water you use to dump the heat into. The hit side is the temp of your water boiler so maybe around 300 centigrade for typical steam turbine or maybe 400 centigrade for a supercritical turbine
Use the same molten salt for both the primary (fuel) loop and the secondary loop, to keep the temperature high and pressure low, with a slightly higher pressure in the 2ndary loop to prevent radioactive leakage into the 2ndary, then exchange down to steam or whatever for turbines.
@@red-baitingswine8816 Carbon Dioxide gas turbines can be very efficient, smaller, and don't have the phase change issues that water at high pressure has.
@@drstrangelove296 Sounds good. Some say that for MCSFR (and FLiBe?), since fuel is so cheap (or you get paid to burn waste!), whichever turbine is overall cheaper to operate is best.
The nuclear presentation was excellent thank you. However, the waste disposal in deep bores is perhaps not as simple as you seem to suggest. This might be a subject for some future presentation perhaps?
If you had read one sentence further on the first Wikipedia page you'd have come across the sentence, "These nuclear materials have other categorizations based on their purity," and that would have linked you to the "Special nuclear material" page that may have been helpful also.
Thank you for making this video!!
Future self: Developing country purchases Thorium reactor, subs out Thorium for U238. Processing plant now processes out Plutonium, makes bombs. Value stream for manufacturers is patents, plant building and export. Developing countries need energy, their leaders want bombs. What is there to prevent this scenario?
Mix Uranium 238/Pu239 and Thorium 232 and Uranium 233 Fuel Cycle
@@shawnnoyes4620Politicians want bombs, will fund a power plant to make them. Hard to get make a bomb out of mixed fuel products.
@@shawnnoyes4620MSRE used something similar, Bechtel says it was there most challenging cleanup, still underway I believe. Politicians want bombs and that is where the government money comes from.
@@rogermorey
You will not do anything, unless it is a military intervention in the country, which will lead to the development of atomic weapons by other countries, i.e. escalation.
It just depends on the promise of the country itself, for example, like South Korea.
Some issues that might be of concern for deep bore nuclear waste disposal might be cooling, accumulation of flammable gases and risk of explosion, accessibility should there be a problem etc. What do you think?
I think in a fast reactor you could just let Pa 233 sit in the reactor vessel until it beta decays, then fissions, as long as the net fissions from total fissile material are enough. (?)
It would really be nice to know the date of the presentation, and the name of the presenter.
I believe I've read that pressurized CO2 is more efficient than water.
CO2 is gaseous at room temperature. Imagine the pressure at 100°, 200°, 1300°C... At the temperatures desired to maximize carnot efficiency, your supercritical CO2 is effectively a bomb waiting to go off. The moment that Murphy's law strikes, you have a nuclear incident.
16:15 This is the sequence: U-238 + n --> U-239 --> Np-239 --> Pu-239.
1/4 through, I don't like the way this is going.
Yes but what happens to the water that leaks into the deep bores it becomes contaminated. The deep bores fill up until they join the water table and then!!!!??? what?
Nice, very informative video.
Can Elysium's MCSFR burn natural Uranium (U238) or Th232, by just leaving them in the reactor vessel until they breed, then fission, and just regularly adding more U238/Th232?
In a fast breeder reactor wouldn't most of the actinides eventually break down inside the reactor after a long period? Like 20 years? Or would they negatively affect the fissioning process too much?
19:00 Woh, was this presentation in **1985**?! If so, I must say, the video quality is pretty good. But I have to question its relevance now, almost 40 years later..
31:00 OK, around now it's obvious this must be much more recent. IAC he's been talking about thorium all along, so clearly this is recent.
52:50: What processes can be switched off and on cheaply to use excess nuclear power? How about desalination? Manufacturing hydrocarbons from CO2 and water?
.
Since some MSRs are inherently load following, could the electricity generation apparatus (exchangers, turbines, etc.) be governed, and the change in exchanger temperatures be conducted back to the reactor, to slow/speed the nuclear reaction?
Most industrial processes are designed to be efficiently run at a constant pace so switching them on/off is usually undesirable. Inherent load following via Negative Temperature Coefficient of Reactivity (NTCR) is not a great idea IMO, because the temperature swings will have an effect on the metal. Just as you can only bend a paperclip so many times before it breaks, the same applies to reactor vessels, piping, heat exchanges, etc... with regard to temperature swings. The more the temperature swings or the more times it swings, the lower the lifespan of those components, or the more expensive they are to design/build to accommodate. Very high NTCR as demonstrated in the solid metallic fueled EBR-II and adopted by most Gen IV designs including most MSRs is a great feature, but mostly from a safety standpoint. Relying on it as the primary reactor control function is a bit dicey unless you intend to replace the entire component regularly, which some MSR designs propose (again, not a great idea as that significantly increases the mass of activated materials that need to be dealt with). IMO, a better approach is to store the generated heat and use it as needed. That way the reactor always run full out at a constant temperature, but it is decoupled from the final use of the energy and all the components that constantly vary in temperature (Steam generators, turbines, etc...) are outside the nuclear island and can be easily repaired/replaced since they are not activated by neutron bombardment.
@@richardbaird1452 Thank you!
@@richardbaird1452
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So then a MSR that's more or less load-following also loses efficiency as the load changes.
Couldn't a fast MSR (e.g. MCSFR) with an initial supply of fissile material, run on natural U (ie. U238) as a breeder reactor, just leaving everything in the reactor and adding U238, for, like, 50 years?
124 years
What to do with nuc waste? Obviously, burn it in a MCSFR. Cheap, safe, energy producing.
Interesting presentation, not sure about the sketching though
Yeah, and having said that, the math skills are very sketchy
Constructive Criticism;
Please deal better with your self corrections.
Protons, I mean Neutrons, I mean 238, no I mean 235??
The way you left both parts hanging left Me thinking, so wait; is he talking about 238 or 235... I used to understand the difference, now I am confused.
It makes what you are saying very confusing, especially if you do not pause after a correction. If you are talking at full speed, and make a correction, you should pause slightly to allow for the listener to catch up and after digesting the correction (after you have corrected yourself) or possibly you could immediately present an example which is particularly important when trying to grasp this stuff.
But really, you should start again; you have a camera. If you say something wrong, stop the camera and start again, don't just say "I mean" and then keep going, but offer half a sentence that only makes sense if the listener knew exactly what you were saying.
It actually sounded like you were answering a question for a test, rather than explaining to an arbitrary listener.
Thanks
If a phrase like "the Early Universe" is relevant to the design and function of a safe Reactor, (maybe the Equivalence Principle applies because a Stopwatch must be used to measure elapsed time), then the reasoning.., Mach's Principle and such like, ..needs to be demonstrated by application to functional standards, (ie in particular, we all want to know why a Big Bang reasoning is relevant?).
I'm attempting to make an Amateur Metastudy and plead for actual Sciencing Re-search to validate the theory or theology of what is REAL Actuality, save the planet, please.
Otherwise, this is another great lecture when on topic.
@ 13 minutes you talk about Candu while pointing to the fast end of the fission cross section diagram- somewhat irritating...
10:05 "All the deuterium that we have was created in the first three minutes..." Not exactly true because deuterium is created in a light water reactor. You said that 2 minutes ago. ;-)
why aren't we converting decaying, spent nuclear waste into usable energy ?
Wikipedia tells me that after a week the spent fuel produces 0.2% of the power it did in the reactor. That's still a lot of heat in many contexts, but it is probably not worth the trouble to design a capturing mechanism in order to increase power plant efficiency by 0.2%. So, using the fuel on site isn't worth the trouble. (The decay heat is ~6% the moment the reactor shuts down, so presumably it is capturing that decay heat when it is actually running.)
This leaves the possibility of using the fuel in some application away from the power plant (e.g. in some sort of district heating setup). I can see two problems with this. First, the heat that you want to harvest from the fuel will make the fuel difficult to transport. Second is that each of these use locations now has the potential to have a spent fuel meltdown if cooling fails (similar to Fukushima). Much better to keep the waste in power plants that have to prepare for those kinds of eventualities anyway.
From what I understand, there is TRISO fuel which can withstand much higher temperatures without melting and releasing vaporised fission products (to the point it can reject enough heat directly to the air to prevent melting). But the point of TRISO fuel (which is more expensive than other forms) is to be able to deploy an entire (small) reactor for your use case in the first place.
Strontium 90 and Caesium 137 could be extracted from the spent fuel after a few years and used for some heating purpose after the hottest fission products decay away (perhaps some kind of Stirling Engine). However, this has to be balanced against the risk of loosing track of the material. There have been a couple incidents of people dying from "orphaned" radioactive sources for medical purposes. Almost by definition, the decay heat becomes more valuable the further you are from the power plant that produced the fission products in the first place. However, that also increases the risk of accidental exposure.
@@lacklustermathie thank you
42:50: Both fast (Elysium, Ed Pheil) and slow (Thorcon) MS reactors can do this, and use all of the contaminated fuel (including, for Elysium's reactors, weapons grade Plutonium and depleted Uranium) to around 100%, since the molten salt (unlike in solid fuel reactors) continuously recycles the fissionable materials, and fission products and transuranics can be removed easily, in concentrated form, when necessary. Check these sources out on TH-cam! The Thorium fuel cycle is somewhat more complex and requires more R&D, but also works quite well.
@@red-baitingswine8816 thank you. i'm severely ignorant on the subject but believe everything can be recycled.
Helion will surpass all that
With a fast reactor, can't the transuranics just be left in the reactor until they eventually absorb neutrons and beta decay into Pu239? How could a U isotope tbat's neither fertile nor fissile be radioactive?
If the neutron energy is high enough, then most TRUs are directly fissionable in a fast spectrum. In the Integral Fast Reactor/EBR-II, all the TRUs including the higher actinides were recycled through the reactor and most were "burnt" directly rather than decaying to Pu first as that takes too long to happen due to extremely long half-lives. That said the concentration needs to be managed so the reactivity of the fuel isn't changed too much.
An isotopes doesn't need to be fertile or fissile to be radioactive. Cs137 is highly radioactive, but neither fertile nor fissile. You are confusing two different things I think. Radioactivity has to do with half-life of the isotopes and it's descendants, not whether it is fertile/fissile.
@@richardbaird1452 (Thank you!) Yes I see, that's logical. An isotope that can decay needn't necessarily decay into something fissile or fertile.
@@richardbaird1452
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Once a fast MSR gets going, is it feasible to fuel it with unenriched Uranium, or some combination of that with nuclear waste or weapons-grade Plutonium, etc.?
Ed Pheil says gas turbines would work fine, and are more efficient than steam, but are more expensive, therefore not useful for MCSFR, for which fuel costs are negative when burning nuc waste.
Breeder reactors are a hot mess and expensive. Expensive to build, operate, maintain and clean up after.
Cheap, clean, simple, and safe compared to solid fuel PWRs. But non- breeder fast MSRs can also just burn every kind nuclear waste as fuel, and at the very least 20 times as efficient as solid fuel reactors.
@@red-baitingswine8816 The Presenter needs to differentiate between soild fuel types. What is said in the vid applies to solid "oxide" fuels, but mostly not to solid "metallic" fuels.
@@richardbaird1452 I had no idea. I read a little on metallic fuel rods. How do they compare with Ed Pheil's MCSFR's? Japan has a process to convert Oxide wastes to Chlorides, and his MSR's use all previously used materials. From what I read metallic fuel rod utilization is 20% or less.
@@red-baitingswine8816 Enrichment of metallic fuel is typically 20%, but that is very different than utilization within an entire system. In both cases you need to do some fuel conditioning/reprocessing to get the utilization numbers up high. For MSR this can be done online or offline. For metallic fuels they dissolve them in salts by applying electrochemical separation techniques (similar to electroplating) not too different than fuel salt conditioning used in MSRs. The FPs remain in the salt and the plated out metallic TRU fuel mixture is re-melted, adjusted for enrichment and cast into new fuel pins and run through the reactor again. Neither is fully developed, however the metallic fuel route has had long run prototype (30 years) in the form of ANL's EBR-II/Integral Fast Reactor. Most of the research on non-aqueous fuel reprocessing was done as part of the IFR. Both Japan and South Korea's non-aqueous programs were based on IFR research. The ORNL MSR prototype only ran for a few years, so is far less mature tech at this point and we haven't seen another MSR since until China's recent small engineering test reactor.
Since the reprocessing techniques are very similar, so is the overall fuel utilization and much shorter radio toxicity of the waste streams.
bye bye
Here's an error. If you build a molten salt reactor, you can store molten salt and use it on demand. That means you can store vast quantities of power as well as use coal and better than natural gas. So no, you don't just turn on a nuclear reactor and use the power as you go.
Not that a MSR shouldn't be connected to a TES or anything, as I can only assume running the fuel salt at a steady state will be desirable. However wouldn't a fuel salts burn-up (heat generation) depend on flow rate across the moderator (up to an extent). Couldn't you simply run a VFD, and just forget about using TES for load following renewables?
Yes you do.
@@mr_happygolucky7095 that’s pretty interesting stuff
@Jordan Howe thanks, I'm a nuclear engineering PhD student. I do Moten Salt, as well as lanthanide-actinide separations, research
@@mr_happygolucky7095 Just remember, MSRs will have limited application due to their excessive cost. Solar and wind will smoke them as their price continues to drop. Then again, you still have to have baseline power. Geothermal will be the only competition to MSRs.
Very good talk,
but i would have like to have the issues with reprocessing mentioned and i don't mean proliferation.
The problem right now is that reprocessing turned out to be a very dirty business.
In fact the chemical reprocessing releases more than two orders of magnitude of radiation more in the environment than the current
light water reactors, so it smears the nuclear waste around the environment creating more trouble than they are use.
Will pyroprocessing really solve this terrible track record of purex reprocessing?