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The Uranium Masterclass

Mark Nelson

Tuesday, May 16, 2023

Chris Keefer  0:09  

Welcome back to decouple. And welcome back for another masterclass, featuring the one and only Mark Nelson. So far we have covered natural gas we have covered coal, petroleum is yet to come, but by popular demand. Today, we tackle the magical Stardust, uranium itself. Mark Nelson, it's, it's been a long time coming on this one, you spent a lot of time researching a topic that you're already intimately familiar with. Me, I'm really looking forward to what comes out today. So welcome back.


Mark Nelson  0:40  

Thank you very much. One of the things you you learn, when you learn is that there's always more to learn, however much you think, you know, that's just a substrate for the next set of lessons, in my opinion.


Chris Keefer  0:52  

So I mean, we're calling this a masterclass. We're also calling it the insane Ium uranium explaining them. Mark, where do we get started? I think we, I mean, we can we can go back billions of years here, right. Let's go back just to


Mark Nelson  1:05  

1789 and talk about that. All right, right. So the discovery of uranium was done by a very early chemist, who, like many of the earliest natural scientists didn't start as a scientist, he started as a drug maker and the apothecary keeper. That was William clapper about the German chemist. And in 1789, he discovered uranium, while messing around with samples of the mineral that was then called pitchblende, because it was a very dark, heavy rock. And so we have the irony that, especially considering the recent closure of nuclear plants in Germany, that it was Germans in Berlin, who discovered uranium, the fuel that Once powered much of Germany, and I believe will in the future to


Chris Keefer  1:54  

I mean, it's fascinating to look at the periodic table and to see how it became populated over the years. Uranium the heaviest naturally occurring elements on said table. What's What's so special about it, Mark?


Mark Nelson  2:06  

Well, you said part of it yourself, right there it is the heaviest naturally occurring elements and significant quantities, we used to be able to say the heaviest naturally occurring element. But we've had to add a phrase because it turns out that some tiny amount of plutonium comes to us on the Earth's surface because of bombardment with waves from outer space, but a tiny amount is formed, and it decays quite rapidly. So there's a just a trace quantity of this plutonium being formed and falling away at the same rate, it's uranium, that's by far the most abundant, super heavy element on the earth.


Chris Keefer  2:46  

Now, and when we say abundant, I want to know how abundant because you know, I've, in my community, there's been anti nuclear folks going around, we have a pelleting plant for Canada reactors, just taking natural uranium making little pellets out of them. And one of these factories is, you know, not far from a school and anti nuclear activists have gone by instead of, you know, a single, you know, essentially an atom could wander and find its way into your lung and you know, bombard the surrounding tissue with alpha radiation and kill your child. And so I mean, I was looking into just how abundant uranium is, in general, throughout the condo cross. And we're going to talk about obviously, the hotspots right here in Team Canada. But how abundant is uranium?


Mark Nelson  3:26  

It's about two to four parts per million in the Earth's crust. And about, I think it's something like three parts for a little bit less than that in seawater, but boy, there's a lot of seawater. So although that doesn't sound like much, that actually makes it 50 times more common than silver, and 500 times more common than gold. Admittedly, we do not use up gold for energy. But it's so interesting to compare the amounts.


Chris Keefer  3:53  

So where are we going? Where are we going now, Mark, I'm eager to dive into the deep past. But we started with the discovery, or we haven't do now.


Mark Nelson  4:01  

Well, first, I think we should note that what what's special about uranium that ends up mattering for us on Earth for energy about that stability part, that stable part is interesting. Turns out, most of the elements as heavy as uranium, tend to fall apart quite rapidly. They naturally decay into something else that's either more stable or self decays again. So uranium is kind of special, because although it's thick and chubby with neutrons, in the form of uranium 238. It stays with us for some time, but let's talk about how we got it in the first place. So there are two theories about where much of Earth's uranium comes from. And one is that a tiny amount of uranium that's President something like think there's a one to 1 trillion ratio of uranium to hydrogen and our sun which is dominated by hydrogen and helium fusion reaction. There's a tiniest amount of uranium in normal stars. And when those stars blow up, especially towards the end of their life when they run out of enough lighter elements to fuse, and they start accumulating more and more heavier elements that don't give off much energy when fuse, the heat of the operation of the stars isn't enough to keep the star from collapsing gravitationally, just due to its own mass, which then causes them to energetically blow up. So it's like a sort of a huff and a puff. And then Blam, you've got, you've got uranium headed out, along with quantities of other things like gold and, and the elements heavier than iron. These would be spewed out in Supernova eruptions or supernova events. Now, there's another source of uranium and that's when neutron stars two neutron stars, these are stars that have fully fully burned out and are basically just clumps of matter. ultra ultra, ultra ultra dense. Two of these stars can circle each other circle faster and faster, and then combine and Blan form a immense amount of super heavy elements. It was these, one of these neutron star interactions that was discovered using the gravity wave detector recently, that was one of the most thrilling discoveries in modern physics. So these neutron stars smashing together act as factories for the super heavy elements of which nooch, uranium 235 and 238, those are both referring to the number of protons and neutrons put together, that would have been spewed out into the local areas of space. It's thought by scientists that several of these dumping events, both supernova eruptions, and also the neutron stars collisions could have led to the supply of uranium that we have on the earth. That is, it wasn't just one blip, it wasn't just one moment, the ratio of uranium 235 to Uranium 238 Production supernova, I think it's something like one to 1.4 to one. So at the beginning, there's pretty close in a similar quantities as uranium 235 and uranium 238. Now, uranium 238 is much more stable, it decays at about the rate of the current age of the Earth itself. What that means is, it's got a half life in the order of several billion years. That means after a few billion years, you can expect half of a quantity of uranium 238, two have decayed into other elements on the way to lead basically. Whereas for uranium 235, the decay is much faster meaning at the present moment in time, with the mixture of uranium that we have from various highly violent stellar events, about 99.3% of Earth's uranium is uranium 238, whereas 0.7% of our current uranium is uranium 235. But like I said, it wasn't always that way. We got several dumps of uranium. And several billion years ago, we had uranium pockets with much higher concentrations of uranium 235. In fact, concentrations of uranium 235 That approached the amounts used in today's reactors, which, in extremely special cases, so far only discovered one flow spot on earth, in West Africa, in Gabon, in the mines near the town of Oklo. We actually had naturally occurring nuclear reactors that operated under pretty much the same principle as our present day nuclear reactors. And what's interesting to me is, they were discovered, after the existence of such phenomenon was predicted by a scientist Paul Kuroda about over a decade before. But I think we're still getting ahead of ourselves because although we've gotten Earths supply of uranium from violent star interactions, deaths, collisions, we haven't yet learned how we get our supply of it. So uranium was distributed in the earth, the proto Earth in rock, but it was evenly distributed, and it needed to be concentrated into pockets for us to find in useful quantities, both to discover as an element early on, if it if we hadn't found such large quantities stuck into pitchblende. Mineral then it would have been unlikely that we would have found uranium until much later with much more sensitive equipment and much more thorough specific searches, but also would have struggled to read Cover amounts that would have been useful for nuclear energy, or, for that matter, the original purpose of uranium nuclear bombs. So I'll go ahead and just put it out there. One of the things that scientists have known for a while, but I've basically never seen it put into such a clear story. Uranium is in pockets, uranium was concentrated by life itself. While at the same time, the decay of uranium in the inside of the earth powers much of the convective force in the mantle that keeps volcanism alive, which is considered one of the primary things that helps protect and produce life on Earth.


Chris Keefer  10:40  

And then the magnetic shield, I guess, right, which prevents the atmosphere being stripped away. Or winds. Yeah,


Mark Nelson  10:46  

from a spinning core of the mantle. Yes, but it's quite important for volcanoes to exist because keeps gases circulating and recirculating and drives continental drift and formation. So here's the here's the story. Uranium has to become dissolvable in water, for water to carry it, to then deposit it at one spot. Otherwise, uranium evenly distributed in rocks. And in fact, uranium has somehow found its way into continental rocks, preferentially to its concentration in the magma from the mantle. So uranium was present in the molten rock, magma in the mantle, came out through volcanoes and ended up accumulating at higher concentrations in continental crust. I think that's quite interesting. And it turns out, the reason why it was able to concentrate is because the water soluble versions of uranium compounds required oxidation. And that oxygen was only made possible by hundreds of millions of years of life, giving off mass quantities of oxygen, more oxygen than the minerals in the Earth's crust could absorb through not rusting per se, but oxidation, which the most famous reaction is rust itself.


Chris Keefer  12:09  

This is the time of the cyanobacteria that one of the most disruptive biological organisms on Earth, the banded iron formations, you know, when when all that that iron became oxidized and deposited throughout the world's oceans, and again, into those kinds of commercially viable deposits of iron, I guess. So what you're saying is similar thing happened with uranium and that life enabled the concentration of uranium to sustain future nuclear powered life? Is that what you're getting?


Mark Nelson  12:38  

Exactly, it's kind of a beautiful picture. Uranium came to the earth, it helps protect life on Earth, the life on earth produced oxygen, which allowed the concentrating of uranium into pockets where we can mine it, and then use it to both flourish as a species as a human species while protecting the other life on Earth by reducing our environmental impact, not just in terms of greenhouse gases, but spatially on the Earth's crust.


Chris Keefer  13:06  

Well, I mean, you heard it here, first, folks, on the couple, this is a thesis, you know, I've been paying attention to this space for quite some time. You know, not just, you know, following great people on Twitter, but reading the great books of folks like James Lovelock, and others. But this is a truly pretty novel idea. Mark, you just, again, I think this is something you came up with as your little spiral of death occurred on the black screen of your computer.


Mark Nelson  13:30  

Yeah, I don't, I don't know if somebody else has already made the point. But all the pieces are there, uranium ended up on Earth from supernovas and neutron stars, it powers the Earth's continued heat to avoid it cooling off and becoming sort of a dead rock life on earth, then provided the oxygen needed to concentrate uranium into deposits that let us mine it effectively, to produce nuclear energy.


Chris Keefer  14:00  

And as we move beyond fossil fuels eventually move into a nuclear powered world. And we're going to talk I think about you know, how sustainable that is or not, and about concerns about the finite nature of of uranium as well. But I think we've got other places to visit along our way on this journey. Are we ready to jump a little more into the attributes of uranium as utility? Are we going to get into mining what's what's next mark?


Mark Nelson  14:26  

Well, I think we could go into something about how uranium ends up in those pockets that allow us to mine it. So there are 15 types of nuclear uranium deposits identified by the IAEA. The two by far the two most important are the ones that we're going to discuss. And they include most of the mines in Kazakhstan and in Canada, that are the source of most of the world's uranium.


Chris Keefer  14:50  

So how did the uranium get into these sweet spots in Canada, Kazakhstan, Australia, I mean, how localized are these? These hike? concentration areas and what's special about them.


Mark Nelson  15:02  

Sometimes they're hyper localized, like there's a bubble of uranium that's maybe a few 100 meters long and maybe 100 or 200 meters wide. And it's hyper concentrated right there at concentrations, you know, hundreds of times other mines and 1000s of times that have normal uranium concentrations in the earth. So, the two most common best deposits for mining uranium are on one hand, unconformity deposits. And second sandstone deposits are mentioned sandstone deposits first. So sandstone is a permeable rock fluids can flow through it sandstone is is where we get a lot of oil and gas for example. And in the case of uranium, water flowing through sandstone carries uranium and other metals dissolved in the water hits a patch where the water chemistry alters and the uranium that had been carried along with the water drops out of solution. So rather than the oxidizing environment that allows uranium to form compounds that are water soluble and float along, it hits a reducing environment, and and it loses the ability to stay in the water and starts concentrating. So for example, in sand stones where this occurs, the grains of sand become covered in in a coat of uranium minerals, like Iran tonight. So what does this mean for us, that means that once you find sandstone typically sandwiched between layers that are not permeable to water, you find a sort of a wave front of uranium flowing along, and you need to find that you need to gather that up and harvest is somehow one of the most common ways. In fact, most of the uranium that is now mined around the world as of 2022 2023, comes not from digging up the uranium, burying sandstone in the uranium deposits themselves. But by sinking wells in front of and behind this wave of uranium pumping through fluid that basically does the reverse operation it carries it dissolves out the uranium and flows it up through the another well, then this fluid bearing lots of uranium is pumped to a processing location, the uranium is stripped out and water is pumped back into the formation. Most of these formations have water that is just simply aquifers that are not drinkable. You cannot drink the water the old water from these formations because they're extremely high and well radiation, dissolved heavy metals, sometimes other elements that are just not acceptable for human consumption. So you're not even altering. You're not involving yourself in water that either plants or animals would eventually end up using. But just in case, this so this process called in situ recovery, i s r is very careful about treating the water and putting in test wells in above and below the formation that has held this uranium for millions or billions of years and make sure that you're not leaking the processed water that you put back in or the water with, say the acid you might have used to recover the uranium depending on this specific formation of rock that you're getting the uranium from, make sure you're not leaking it outside of


Chris Keefer  18:33  

this. It's a little bit like you know, this is a big stretch but a bit like no till agriculture not needing to do a big open pit mine or not need to dynamite out tunnels and do it hardrock mining, it sounds like it's less invasive, there's still, you know, environmental concerns to manage in terms of the water treatment, you're not having to move it around a huge amount of rock, which is you know, such a such a huge part of the energy use of mining and the environmental impact.


Mark Nelson  18:57  

Yeah, I mean, there's not a lot to look at it mines like this, to be quite frank, there's no big hole, there's only a few structures on the surface, there's a few little things that look like miniature wellheads that are just the surface pumps. And yeah, the fact that this is over half of the uranium supplies that we're now getting out of the ground, which is approximately, let's say approximately half of uranium power that we're getting around the world which is 10% of global electricity. This means a few 100 million people are getting electricity from mines that don't even wouldn't even be recognized as mines to the public.


Chris Keefer  19:35  

Okay, said sandstone was one of the big deposits I was talking with a Canadian prospector and as you were saying, I mean the concentrations can be very variable Canada has some really incredible or or grades approaching 20% But he was saying there's little pockets within these org raids where you might be 60% uranium and of course we have this burn everything. Reactor you're in Canada called the Canada he was saying you could press these things into pellets and Put them into a candle and you know, wouldn't run as perfectly as if they were, you know, entirely uranium. But I mean, just, I think this this concept of how the ore grade can vary, is pretty incredible, average order around the world of 0.07, Canadian or grade up to about 20%. Now how to things look over in Kazakhstan or other places around the world? How do they compete with Canada,


Mark Nelson  20:21  

Canada's got superlative, or there's nothing like Canada. And that's why I came can't wait to get into this unconformity deposit discussion because I went to cigar Lake mine, the mine currently producing essentially all of Canada's uranium. And I'm going to be able to describe that with first hand knowledge. The deposits elsewhere are between 10 and 100 times less concentrated. So there's means you need to mine 10 to 100 times more material to recover the same amount of uranium. Now with in situ recovery, you're not physically mining it out of the earth, but it's still it still involves, I don't want to say that mine is better Chris and the Canadian mines are better just because the uranium is so concentrated. But it's hard to it's hard not to feel a little bit proud of our North American uranium production if I can say that as an American. So for example, the infamous mines in southwest United States, the ones that were mined with, let's just face it artisanal methods with all the health damages and safety risks associated. These are the, for example, the Navajo uranium miners that worked in horrible conditions, and suffered health problems due to that, well, these were mines that were much lower grade than the Canadian mines, and were only being mined because of the US government's absolute insistence on self sufficiency of uranium supplies for its nuclear weapons programs. Whereas it was okay to get uranium for nuclear power reactors from other sources. The US government was very sensitive as many governments would be about getting essential elements for its its weapons for its nuclear fleet from outside the United States. Otherwise, as soon as the price for uranium fell a bit in the 80s. All those mines shut down and we've been getting uranium from from Canada ever since.


Chris Keefer  22:20  

So discontinue this continue with the deposits that was the


Mark Nelson  22:24  

unconformity. This is a term from geology referring to rocks that were laid down that are sitting next to each other but laid down at different times. And the deposits these ultra high purity deposits in Canada, which so for example of cigar Lake mine, which is the mine I visited last summer that has an average ore grade of 16% uranium with patches, little bits above 70%. If you could see these these are almost pure, you owe to uranium dioxide, which ends up being what you need for nuclear reactors. You just have to processes to get the other stuff out concentrate the you there's steps in between and we'll get to that. So why don't I describe why these unconformity deposits form. What I heard when I visited the good folks up in Saskatoon at Cameco. They say you look for uranium, where water once flowed, you're looking for deposits that concentrated lots of flows of water through a patch a pocket and you need something that trapped that pocket and change the water chemistry at that pocket to precipitate out uranium in a very tight spot over a long period of time. And sure enough, that's where the ore body that makes up the cigar Lake line mine and the ore body that makes up the MacArthur River Mine, which is the largest single deposit of high grade uranium ever discovered was cigar Lake being the largest in current production. So what happened basically is there's a pocket of rock the basement rock that comes from metamorphic rock from a very long time ago above that is sandstone. And those sandstone layers have imperfections that form the features we just mentioned. So like a clay cap that it's impermeable to water flow, but fault fracture lines that allow the water to flow in. And then these bed this bedrock underneath allows a water to carry water chemistry that precipitates out the uranium that's flowing in from the above, basically. And so it's like this pocket traps and filters out the uranium water keeps flowing onwards and the uranium stays. And it just happened over an extremely long period of time. Something like 1.61 point 7 billion years ago. And there's a number of these pockets we know that there's a bunch of these pockets sees orebodies of high grade uranium scattered across the Athabasca basin of formation that underlies, say, northern Saskatchewan and a lot of the Canadian Shield. So we know that there are more of these ore bodies out there, but they're a little bit tricky to find. As you may know, Canada is very big, the formation where this might happen is very big. And it's a little bit like finding a needle in a haystack.


Chris Keefer  25:23  

Alright, well, I think that's, that's going to help our prospecting nerds understand a little bit more about where to find it, how it concentrates. Let's get on to some other exciting material. Well, let's


Mark Nelson  25:33  

harvest it. That's so let's,


Chris Keefer  25:36  

let's talk about the mind the mind visit I love and I love getting descriptions of people that have been on the ground, you've you've described your odd sort of visiting a coal plant and looking through that bit of tempered glass to see what's going on in the belly of the beast. What was it like visiting cigar Lake,


Mark Nelson  25:49  

you know what's terrible. And I complained to my lovely hosts about this, too, I didn't get to see any uranium, I knew that the uranium in such high concentration concentrations would be this gorgeous black, shiny, sparkly mineral, or blend of minerals. And I didn't get to see any Chris. But that tells you something about how I don't know how pristine how clean how self contained this mining operation is. So let me describe first how Cameco attempted to mine cigar Lake and why that failed. So there's this uranium pocket in this waterlogged rock formation, sitting above a hard rock basement. So the first attempt was to dig a big hole down, go right into the ore body and try to gather it up. But they the mind walls kept collapsing in that kept pressing and water kept leaking. And there was nothing they could do to stop the ground literally from shifting, not under their feet, but I guess around their feet down in the tunnels. So this formation is taking place over 400 meters deep. So it's over 1200 feet deep in the earth. And the pressure there is high such that when they gathered up the material out either to make the tunnel or to start mining the uranium, they couldn't keep the tunnel from collapsing. So they had to get that they had to shut down and take a completely different approach. They did invent a new approach just for that hyper concentrated pocket a bore. And to give you a sense of how much uranium is there. There's about 99,000 tons of uranium. If once you concentrated, it's enough to power the world's reactors for a little over a year. Or putting it this way at the current harvesting rates of uranium from cigar lake. I think it's about 4000 4000 tonnes a year. Or I guess about sorry, about 4 million pounds a year. It's enough to power 300 terawatt hours of electricity production from modern reactors. So does that mean it's a big mine? No. I'm about to describe what they did to solve this really tricky collected tunnel collapse problem. But first, I'll say that you can walk across the surface area of cigar Lake mine and just a few minutes to get there. You basically have to fly. So workers fly in for multi day shifts and then fly out to home. And it's still considered an absolutely outstanding job and you're up in really stunning wilderness area. Basically, it is a land of lakes and forests, sort of rolling bumpy hills and lakes as far as the eye can see. It was kind of intimidating to see this landscape because it kept going on and on and on. And I know Canada famously as the most lakes of any country think it's several million felt like you were seeing a bunch of them right there surrounding the mind. So there's a lot of water and that means water quality and water protection is a very high priority. So here's how they solve the mind issue. They sunk a tunnel down below, below the basement bedrock and that gives them the stability to be able to drill tunnels that don't collapse, but then they're stuck under the ore body the ore body is above. Then they put dozens of wells to pump freezing solutions down to freeze the entire ore body into a solid shape to keep it rigid while they mined bits of it. Okay good. So that's going to stabilize the this waterlogged ore body filled with uranium minerals. In fact, we might think of it as a little bit like a frappuccino a mocha chip Brackett Frappuccino a frozen slurry of bits of uranium, water and other rocks and minerals. So we've got our tunnels underneath a frozen frappucino of of uranium above. Then they put in tracks to tunnels that go back and forth under the ore body itself and this ore body. I could rotate it or round for you, it's sort of shaped like the I think it looked like a lizard. But the folks running the mind hadn't noticed that before. And I don't think it's going to stick the lizard. So it also looks a bit like a modern airport arrivals hall like a big arrivals hall a couple of 100 meters long, sort of blob shape. So with the tunnels on board through the hard rock underneath, and little rails installed to bring equipment in, then they drill directly vertically above their own heads up through the little cap of base mat rock into the ore body itself, the frozen ore body, and then they stick in a little internal pipe through this through this tube, and they spray ultra high pressure water, combined with a few other say gritty materials to help cut into this frozen uranium sediment. And then they spray and an arcing pattern. And they just start pressure washing the inside of these cavities basically making a cylinder of, of uranium slurry that is then sucked down through the tube pumped to an area of the mind where it's allowed to settle a little bit. And then they put in thickeners and pump it back up to the surface. So that's that that's the point at which the straw is properly drinking the frozen Frappuccino of uranium up at the surface, then the uranium is concentrated at a mill and is eventually turned into nuclear fuel. So these little tunnels have the drilling machines and I'm putting pipes up spraying with with water and ultra high pressures to wash the uranium down into the straw, and then piped around to the holding pin and then pulled up to the surface. And then finally, finally, each, each sort of straw suction hole is back filled with concrete to stabilize the formation to prevent it from collapsing. So nature did all this hard work putting uranium in that one spot. You don't want it doing any movement or migrating that isn't you harvesting it?


Chris Keefer  32:10  

What are the what are the kind of tailing ponds and things look like at a facility like this,


Mark Nelson  32:14  

there's very little compared to traditional mines. For one, the uranium is in concentrations of 16 17% On average, with spots of up to 70%. That means that relative to most mines, you're barely moving any material at all. So in fact, even though water is used to spray out these tunnels and to to to move the mineral itself, each batch of water is tested for its its purity after being filtered before being released from the mind. And then the tailing ponds themselves are quite they're not even ponds or piles that themselves are tightly monitored. And, and in fact, this makes an interesting situation. I've heard people say, wouldn't it be good if we got more minerals out of the tailings or if we extracted more or if we got different types of substances? Well, I asked the folks at Cameco at cigar Lake about this and they said that the problem is they have such a specific permit and specific balance between the environmental regulators and how they accomplish their mission that they disturbing that by proposing to do anything with the tailings is a bigger paper risk, big paperwork risk than it is worth any minerals you might get out of it. But yeah, the tailings are there in a very specific area. And it's known exactly how big the ore body is and how much is going to be taken out so they can size the tailings holding area very specifically long in advance.


Chris Keefer  33:49  

And I hope to get up there one day and have a look for myself. So what's the next mark where we're gonna move to next I think we'll probably wrap that section up in a bow. Once it gets out of the mind gets milled and gets to a power reactor and does does the magic stuff walk us through


Mark Nelson  34:04  

so we can briefly mention those steps. Once it's coming once the uranium concentrate or once the uranium ore comes out of the mine, it goes to a mill in the mills it's crushed further into very fine into well crushed into small particles than its ground and even finer particles to make a maximum amount of surface area that then a substance that say sulfuric acid as the most common would be used to extract specifically the uranium and then that is dried and concentrated in the form of uranium. Try uranium oxide oxide or you 308 which we know as yellowcake why yellowcake Well, it happens to be yellow at that oxidation state. And then this is the substance that was that can cause panic, for example, occasionally hair you know 50 pounds of yellow cake Miss Seeing from such and such I just a few weeks ago that caused a panic. I remember hearing about yellowcake for the first time in the run up to the Iraq War when it was used as one of the excuses Saddam was getting yellowcake This is uranium, you 308 that is the result of the mill. So it can't go into a reactor yet. I mean, it's nearly ready for CANDU reactors, which are able to use this 99.3% You three are you 238 0.7% you to 35 mix, but in most reactors on planet Earth, we need a higher concentration of uranium 235 to get the reactor going. And that's because uranium 235 is more unstable, more likely to split and start your fission reaction with a lot smaller amount of fuel than is required if you had just uranium 238. And you can also use different substances in your reactor as opposed to a little bit more limited in what how you can run your reactor if you're running it off of natural uranium, you have to scrimp and scrounge every single neutron you can, you can't waste any basically, if you're going to run off of natural uranium. So most reactors in the world include uranium concentration, what happens then is that you 308 yellowcake is turned into a gas, you F six uranium hexafluoride, this is a very heavy gas that goes into canisters and this gas then is fed into gas centrifuges, these gas centrifuges spin very quickly. Now, it's difficult to separate these two things because the chemistry so the electron part is base is the same. It's the nucleus that's different. And to just give you an example of a property of uranium chemistry that has essentially nothing to do with the nucleus, I have a little bit of uranium glass here. So this used to be this is an artifact, a precious artifact that really belongs in a museum. It was in the upstairs office area of environmental progress in Berkeley, California, where the pro nuclear movement was practically launched by Michael Shellenberger from 2016 onwards, and this is what would hold piles of cashew, or pistachio shells, as we worked on a difficult problem for two and then three, and sometimes four hours in a row, trying to untangle history, and culture, and engineering and physics all at once. So this is the dish that used to sit up and gather the pistachio shells when the environmental progress offices closed. Sadly, as one of the many victims of the pandemic, I was ruthless and trying to obtain this, I think Michael may still want it back. But you can take it off my cold dead hands.


Unknown Speaker  37:54  

It's fluorescent, yeah,


Mark Nelson  37:55  

it's fluorescing. And is if I turn off the black light, it stops glowing immediately that differentiates it from phosphorescence, where there's a delay between the absorption of the light and the readmission. It's phosphorescence, that's kind of given the green glow of The Simpsons and of the popular imagination to nuclear waste is really hard to associate the fluorescing of uranium glass like this, which is the electrons in the uranium, absorbing the the UV light, and then immediately remitting them at a very specific energy level. And that's this green wavelength. So it's a cool effect. But it's hard to say I agree with my friend and colleague James Collins senior says that no, it's the phosphorescence of other materials, like radium compounds that gives the gives the popular green glow rather than the fluorescence of this glass. But that's an example of a an aspect of the electron configuration rather than the nucleus. But the nucleus having a mass difference, it's very small, barely 1% is what's giving us the ability to sort uranium 235 from you to 38, which is the essential process, this concentrating process of getting more of the light nucleuses and fewer of the heavy nucleuses more of the light isotopes that is the same element, but just different numbers of neutrons from the heavier ones. So these gas centrifuges spin very fast. We take out the gas with a slightly higher percentage of you to 35 and at the start of the cylinder, and we do this over and over and over through a cascade of multiple gas cylinders. And that's what allows us to get a higher concentration of you 235 How high will higher than the 3.5 3.6 3.7% of the naturally occurring reactors from billions of years ago and Gabon, up to about 4.8% is about the highest levels of enrichment currently being used in reactors today. At those higher levels of enrichment, again, allow a longer residence time of the fuel in the reactor. That means potentially longer times between refueling things, giving nuclear, it's incredible property of just going for years without a stop.


Chris Keefer  40:16  

Right? Right. So you get that gas and then that's that's been turned into, I mean, right now ceramic fuel pellets, maybe metal fuels in the future other other kinds of options down the road, when


Mark Nelson  40:25  

you get the gas back out of the enrichment stage, you now have cylinders of uranium hexafluoride that are just higher concentrations of YouTube 35 versus YouTube 38. These cylinders will then go to a facility sometimes the same facility to be d converted, converted back into the forms of uranium necessary for fuel. So you owe two is the vast majority of this, there's occasionally a little bit of you 308 used to get exactly the right grain properties and density properties and the final pellet. But once you have uranium dioxide, then this needs to be compacted and centered and made into these precisely machined, exactly machined little pellets with Ultra tight tolerances. They're like each one, a little work of art. It's when you hear about each of these steps, it's almost a wonder that we can afford nuclear fuel at all. But that main thing that allows us to compare uranium and this uranium masterclass to the gas and the gas masterclass, and even the coal, and that is about a 100,000 to one ratio of coal to Uranium needed for the same amount of generated heat. And then with gas, the numbers just get ridiculous because gas is several 100 times less dense than coal. At standard temperatures and pressures you need in terms of volume, you need about 600 times more volume than that 100,000 times more coal, when compressed into liquefied natural gas, it's similar, similar to coal. So 100,000 times more LNG than then the little bitty pellet, you would need to power your life for a year,


Chris Keefer  42:15  

which I think which is what makes like the uranium cycle. And this isn't a podcast, we're gonna get into like investment theses and things like that. But because you can stockpile uranium it's not something that's being consumed. So quickly after it's produced, like petroleum or gas, it leads to these kind of cyclical nature. I mean, I guess petroleum is also cyclical in terms of of sales and things like that. But I just I'm struck by this ability because of how concentrated it is to store up large amounts of it to bolster energy security, even for countries that don't produce their own uranium. Like there's something there's something special beyond the energy density here, which speaks to where and why nuclear gets deployed around the world in island nations that are fossil fuel even uranium poor, like Japan or functional islands like South Korea.


Mark Nelson  42:57  

Well, it's said that the greatest energy storage system in the world is the American natural gas pipeline, which holds holds. I believe it's hundreds or even low 1000s of terawatt hours of heat at any given moment. Well, if you want, you can set up a bank for nuclear fuel and you can stockpile at any point of that process. fuel assemblies ready to go. Now that's not as common because fuel assemblies are precisely manufactured for the working conditions inside each nuclear core. So there's people at each power plant that order up an extremely precise recipe and amount of fuel with various specific dimensions from fuel supplier. So there's a tight relationship between a fuel supplier and a nuclear plant supplier doesn't mean there can't be multiple fuel suppliers. And in fact, Western fuel suppliers, Westinghouse in particular, stepped in to provide an alternative to Russian fuel suppliers for fueling Soviet designed reactors around Central and Eastern Europe. When tension started really boiling over, especially in 2014, with the capture of Crimea, people with Russian design plans with Soviet design plans worked hard to make sure that other fuel suppliers could precisely machine exactly the shape and exactly the type of fuel needed for their reactors. So it's not like you can't get alternatives. It's just you if you're stockpiling uranium fuel, best not to do it at the stage where the last bits of machining are done. Now, from the perspective of each plant, sure, you can stockpile more of your own fuel if you know what you want your core loads to be at different times. So where would you stockpile one possibility, probably one of the smartest is uranium dioxide already in an enriched state or you 308 In an enriched state downconverted from UF six uranium hexafluoride or you could store Collins Isn't traded uranium 235 in the form of uranium hexafluoride. And in fact, you could store the enriched part. So at each one of these steps, you could bank an immense amount of the world's energy by just a tiny area dedicated to this, because it's so energy dense, you don't need the entirety of the American pipeline system with all the natural gas storage caverns. To supply that amount of energy, you would just need to ramp up production for a few years above the needs of current reactors, and stockpile the components along that process. The IAEA, the International Atomic Energy Agency has in fact established a Leu low enriched uranium, so between three and 5% fuel bank in Kazakhstan, to give countries the certainty or at least the confidence that they will be able to get fuel, even with disruption of supplies in the case of war. And this is an A gesture by the IAEA to encourage countries to forego their own independent overproduction of different fuel supply components. Because that can lead to issues like say Iran claiming we don't trust the West, we don't trust anyone. We want our own enrichment, our own conversion, we want our own steps to fuel our own reactors, and the same enrichment that gets you from 0.7% uranium 235 Up to three, four or 5%. For today's reactors. That exact same process on the same machines can get you up to 20%, which is the line for for commercially acceptable fuels today, that's considered the halo high assay low enriched uranium is at 5% to 20%. Above that, you start to get to say military grades, where some of the most powerful and effective military reactors are going to be operating above 80%. Enriched Uranium and bomb grade uranium is 90% and above.


Chris Keefer  47:04  

Okay, so get this mark. I was preparing at length for this great Canadian Nuclear debate. You can look back in the show notes a couple of episodes ago, and ended up speaking a lot to folks working in medical and research reactors making isotopes we make them in our big candle reactors at scale, certain ones like cobalt, 60, lutetium 177, but we also have a 59 year old reactor at my alma mater, McMaster University went to medical school. And they make a lot of the worlds I had on 125 used for these bracket therapies for prostate cancer, a number of other cool medical isotopes, and I really deep dived it with them, because I thought this was a really interesting area to draw attention to in the debate, because nuclear technology runs the breadth as we've seen, the reason I'm bringing this up, they in the last decade, they've started to run research reactors on less enriched uranium that come down to the halo level. Up until about 10 years ago, those research reactors were using 90% Plus highly enriched uranium, which I thought was just crazy. We can


Mark Nelson  48:09  

run for a really long time, Chris, without me I'm sure that data fueled you get many decades of great research out of that. Yeah,


Chris Keefer  48:17  

no, absolutely. Absolutely. Is absolutely fascinating. And I don't want to get too sidetracked with it, but absolutely phenomenal that work happening at McMaster research reactor. They do neutron radiography there. Every single blade on every jet turbine made in North America makes its way through that facility for the quality control mechanisms that a required. So really cool stuff happening, get those research reactors and yes, up until recently, they were using 90 plus percent enriched uranium they've converted to to the halal you're just mentioning. Now, you did see something interesting, we've been talking about the stockpiling about national security and stuff. Obviously, we've been big on poking Germany for its reliance on Russian natural gas. But in regards to that question of energy security and Russia, producing I think over about 43% of the world's enriched uranium. How is Russian natural gas dependence any different than Russian uranium enriched uranium dependence for countries like Europe and even the US?


Mark Nelson  49:14  

So first of all, to disentangle something Russia uses about as much uranium as it produces. The issue people have is that there are aspects of the fuel cycle like the conversion and deconversion to and from uranium hexafluoride for use in the enrichment stage and then the enrichment stage itself where German reactors did have contracts for some of this process through Russian entities. Well, here's the big one. If Russia cuts you off today from fuel, you have up to a year and a half or even longer up to two years maybe before that stops your reactor. If you somehow can't get it from anywhere else in the world, which would be doubtful you would almost certainly be able to find quantities of Fuel somewhere. And it's possible to scale up pretty much each of these parts of the process more enrichment, more mining, more conversion pretty rapidly. The reason why companies don't like to scale up their capacity rapidly is because it can completely tank market prices. And once that happens, the industry splits between the people benefiting from the crashing prices and fuel components, that is the nuclear operators, for example, and the folks that that need higher prices to not go bankrupt. That is that people who expanded their factories all of a sudden, so the issue isn't so much can we the issue is, are we offering guarantees to expand that production to the people who would have to invest a lot of money to expand their facilities, if we're needing to prepare for a cut off of Russian fuel. So one issue is that length of time you have which is much longer if the gas stops flowing, your pipelines and your storage, even if your storage was filled, you the clock is ticking, you have a very small amount of time before you burn through your gas stockpiles at the rate that German industry and power plants use them. That is not the case with the uranium in the plants itself. So it's, it's just fundamentally dishonest. Also, the cost of getting uranium fuels into the plant, even if it sharply jumps. If you have to switch from your Russian contracts to other suppliers, it barely affects the cost of production of nuclear energy itself. So one of the basic rules of thumb is that the fuel everything from the mining, milling, conversion, enrichment, deconversion, fuel fabrication delivery, installation and the reactor, that's going to be something between 20% and a third of the cost of generating nuclear electricity. That's just not enough to make nuclear uncompetitive against pretty much any other way of making stable power in Europe.


Chris Keefer  52:00  

Yeah, when you describe the complexity of you know how to actually make enriched fuel, it's astounding that that it's such a small piece of the final kilowatt hour price.


Mark Nelson  52:09  

And that's just the extreme amount of energy you get out of each fission reaction. I think we may have said this on a previous podcast, but just in case splitting, one uranium atom, compared to burning one methane molecule. So ch four, which would be the stuff that that most of what Russia was getting through pipelines from Germany, just tells you this massive difference. So oxidizing or burning, combusting one ch four molecule into co2 and h2o, gives you about 10 electron volts of heat energy to play around with splitting one uranium atom gives you about 200 million electron volts to play around with, with various losses and inefficiencies and, and, you know, issues along the way, you're down to about 100,000 to one difference in the mass of the fuels needed to make similar amounts of electricity. So you don't get you don't get all of that back, you get a lot of it back. That's the difference that allows independence, even when dealing with other people's uranium supplies, even dealing with other people's fuel supplies.


Chris Keefer  53:24  

Well, let's maybe close the loop here by talking a little bit about how much uranium we actually have. I mean, for those of us who are proponents for increasing the share of energy and electricity that we get from nuclear, one of the frequent objections is, you know, that's a great plan, but we're going to run out and 70 years. You know, I've seen different estimates, such as the one I just referenced there, and also Nick terrains done some work on this. This obviously involves talking a little bit about fast neutron reactors. Without getting too far into those weeds. What are your opinions on on the sustainability, the renewability, of of uranium and nuclear,


Mark Nelson  54:04  

it's renewable. So uranium is constantly coming up to the crust going going into crushed rock and being deposited into the oceans, and it's been happening for billions of years. So we have an immense amount of uranium out there, depending on what concentration we decide is acceptable for mining. Because uranium is such a small percentage of the price of fuel, then the price of uranium can go up drastically and make all the uranium investors rich beyond their wildest imaginations, without stopping nuclear energy from being cost effective. And you can do that by not only finding more cigar Lake mines or more MacArthur river mines or Olympic Dam mines like in Australia, you can find more of these deposits. If there was a resource bubble, a resource cycled where a sustained period of higher prices drove aggressive exploring, you would find more Are these pockets, but we can also, in the end, do two major things. One, we can breed more fuel that is used existing uranium hundreds of times more effectively. Even up to 1000s, depending on which processes we're talking about how complete the recycle is of the fuel. So for example, in France, France recycles its fuel once to get about double the energy out per atom of mined uranium. So that's pretty good. But if you were then to run reactors that breed more fuel out of existing 238, then you start to open up a fairly extreme amount of energy, you start looking at current existing proved resources in mines ready to roll if prices were to rise high enough, have several 1000 years of fuel to provide the primary energy for all of human civilization. At a wealthy standard for 10 billion people, you're in the low 1000s of years. If you're using breeder reactors, at the point that you open your resources to include say, thorium. And if you open your resources to say you special sponges and mats actually filter uranium out of the ocean, like these sort of artificial kelp beds of uranium filtering material, that you then squeeze out to get the you get the uranium minerals. Once you do that, and combine it with breeders, you're looking at several billion years of fuel in combination with land based resources. At that point, Chris, you're going to last until the star burns off the Earth's atmosphere, which is our star, the Sun, which if it doesn't give us enough uranium to make it worth our while, I just assumed not prefer to have our atmosphere burned off that at that point, you're going to have issues with say solar panels and wind turbines anyway. So when you add up all these processes, you have dozens of years with no changes hundreds of years with a few changes 1000s of years with a few more changes, and millions to billions of years with harvesting more and being more efficient with your use of those in future reactors. And a number of countries have worked on these fast breeder reactors and are continuing to work today. I myself just a few days ago visited Argonne National Labs where fast breeder technology was really pushed forward earlier. And I saw the test facilities they're going to use to help reactor developers, of which there are many show that their safety shutdown and cooling system passive cooling. natural circulation cooling systems for these fast breeder reactors will work. At which point you need to commercialize the recycling technology that would recycle efficiently recycle the isotopes that can be put back in the reactor to be bred and burned more, and then you're off to the races. You're good for a few billion years at that point.


Chris Keefer  57:59  

Very interesting. Well, we're certainly going to have some episodes to follow up on on this notion of fast reactors that's a bit of a hole in the decoupled archives to this point. But Mark, this is an excellent recap and review I've learned a lot. Anything else that you wanted to touch on today, to put the bow on on this uranium masterclass.


Mark Nelson  58:22  

Just to re emphasize the beauty of this story, stellar collisions and and explosions gave us our uranium. Our Uranium then showed up on Earth and helped make life possible. The Life helped through weathering through through production of oxygen helped concentrate the uranium into the mines, where we can now find it efficiently and easily when we're just a baby species just beginning to get our foothold in nuclear energy that will power us to the stars. And that's going to help us protect the rest of the biosphere. I think that's such an extraordinary story that makes me feel even as somebody who's been involved in nuclear for a decade now makes me feel even better about the rightness the naturalness, but also the agency that uranium has given us to write our own fate environmentally and socially.


Chris Keefer  59:17  

Well, I think no one will question your enthusiasm and and faith in the atom now Mark they ever did before. Thank you for coming back on decouple my friend. I'm sure this one's going to be a big hit. And we got to get to catch up going on the petroleum master class and so much more. So looking forward to to those happy occasions but for now, my friend, good luck and farewell and we'll see you back soon. I'll


Mark Nelson  59:40  

see you again soon.



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