B (3:06)

Doctor Jenn Schaefer is a professor at the Colorado School of Mines. And before that she was at ARPA E, the Department of Energy and pnnl. All focused in this area. Here's Jen. Jen, welcome.

D (3:18)

Yeah, thanks. Thanks for having me on.

B (3:20)

So let's talk about nuclear waste. First of all, what is it actually like? What is the waste that we care about?

D (3:27)

Right. So nuclear waste is basically any commercial waste that the US has is uranium dioxide. Basically ceramic is the way that I describe it, what's made out of your coffee mug there. And it has many things from the periodic table and it's a largely second row transition metals, early second row transition metals, as well as lanthanides, as well as basically some actinides heavier than uranium. And what this means is that the uranium composition as far as the actual irradiated meat ends up being about 95% of the material. And then the other 5% are these fission products that grow in over the course of the irradiation as well as what I call the transmutation products. Basically when the uranium gets struck by a neutron, captures that neutron instead of fissioning and that grows into your plutonium, your neptunium, your americium, all these sorts of pieces. Right. So that's largely what it's comprising of. It stays in the fuel. It's a solid. Some people are surprised to learn that it's not a liquid goo. I've just been watching Teenage Mutant Ninja Turtles with the kids recently. So that's not what it is.

B (4:35)

Also the Simpsons. Also the Simpsons Green radioactive goo. Yep.

D (4:39)

Right. So people are surprised when it's just a dry cask sort of material that is very intentionally not liquid.

B (4:46)

Right. And so 95% of it is, as I understand it, 95% of it is the stuff we don't worry so much about, but we worry a lot about that 5%. Right. And that, that 5% is comprised of at least in part a bunch of these isotopes that have various degrees of radioactivity and various half lives. Can you just kind of like break it down a little bit?

D (5:11)

Yeah, so we can get into that a little bit more. So your, your actinides and your minor actinides, so your plutonium, your neptunium, your americium. So all those sorts things are grow in and they basically constitute the long term waste management burden for the nuclear material. And this is something that's very different than what you have Say in fusion nuclear waste. Right. Because fusion nuclear waste is just activation products. It's basically your transition metals and other things that were radiated over the course of that. And so that maybe comprises about 1% of it by volume with respect to that. And then you have this 4% of other material that are your fission products. And so those are things that if you're able to take them out for the most part could generate a waste management timeline of on the order of more like several hundred years. Not talking about something on the order of millions of years. There are exceptions to that. For example, Technetium 99 has a very long waste management burden. Things like iodine one, I believe, I forget if it's 129, 131, that also can have a very long waste management burden. So there are a couple of standouts from that perspective. But it's largely your actinides that drive that waste management challenge over the long haul.

B (6:27)

All right, so I think when we think of nuclear waste, we think of a waste management life, the amount of time that we're going to have to deal with the radioactivity of this stuff as being, I don't know, tens of thousands of years at least, if not millions of years.

D (6:40)

Yeah, the legal limit on Yucca mountain was the 10,000 year management obligation. Practically the waste sticks around for longer than that. But that was what the obligation was legally for Yucca Mountain.

B (6:53)

But I guess I'm just trying to reconcile what you're saying about the vast majority of it being, you know, hundreds of years versus Right. We think about Yucca Mountain as being tens of thousands of years and some things lasting even longer than that. Is it just that like is just a quantity difference? Like there's a lot of a portion of that 5% that is it is 200 year life or whatever, and then a very tiny fraction that is a million year life or I don't know, how do I think about that?

D (7:21)

That's the right way to think about it. There is a very small fraction that comprises a lifetime that's potentially on the order of millions of years that you have to manage and obligate. And really it boils down to the social construct of we decided when it comes to regulating nuclear waste that when we generate it, we are going to manage it for the long haul. And so basically because we don't do anything with respect to separation management, et cetera, that material all stays within there. And as a consequence of that, you take that material and ideally you take it to a geological repository for disposal at some point, and this was something that, not to jump into this too much that we debated quite a bit in the 70s about how we were going to handle and manage this waste. Were we going to do basically a mined repository, which is what we settled on, Were we going to launch it up into space, we going to put it in the Marianas Trench? Like all of these things were considered. And ultimately for a variety of reasons, we decided that deep geological disposal was what made sense with respect to that.

B (8:25)

So which of course we'll come back to, but we have not actually done. It was just the decision that we made.

D (8:30)

Right, we have not actually.

B (8:33)

But okay, so you get this waste product, a lot of it, you know, when people talk about nuclear fuel recycling, just to be clear, that's because as you said, 95% of it is like, or some high portion is unreacted uranium basically. And you could separate that out and then turn that back into fresh fuel. That doesn't, that doesn't end the waste problem. Of course, you still have that 5%. In fact, when you react the unreacted 95%, then you get more waste products. So it's a solution to not needing as much new enriched uranium is not a solution to the waste challenge. And then we, right, we, and then we get this waste and it within that 5% that is radioactive. It's like a cascade of different things that have different degrees of at least shelf life or half life. Is it different degrees of danger as well? There's some stuff that's actually like, you know, in theory, if that's all we had, we could handle it. Like we handle many other toxic or corrosive things. We ship ammonia all over the world. Like is it that level of a type of thing? And then there's some others that are super duper radioactive or is it all pretty consistent?

D (9:42)

Right. So there's lots of different things to touch on with, you know, some of the things that you were observing there. Right. So with respect to recycling the material and that potentially being a pathway to minimize waste versus not, this is something that is really discussed quite a bit. And one of the things that you have to keep in mind is so say you're, you irradiate some fuel and you take that fuel and you pull it back out, right? And then if you don't recycle or you operate what is basically an open fuel cycle, which is what the US does, right. Then you are then taking more fresh material and irradiating it and pulling it out. And so what you have is a Scenario where now you basically have double the amount of material that you potentially needed, as opposed to if you had just taken that material that you originally irradiated, chopped it up, dissolved it, recycling it, now you've got, instead of, you know, in the open fuel cycle scenario where you've doubled the amount of waste that you have just in that example, now you could take that material and basically say, okay, I'm going to take that 95% of the material that I could still irradiate and put into fuel and just put that back into the reactor, right? So you're basically reusing the same material. And so the argument I would present there is you are actually minimizing the amount of radioactive waste that you're generating through that mechanism. But you still have to manage the material that you've developed, right? And then there are a couple of different pieces within that, right? So if you look at the actinides, right, these are the things that are sticking around for anywhere from tens of thousands of years to millions of years. Those are things that you could take back into a reactor, radiate them, split them up into things that are your fission products. The fission products nominally have the shorter half lives, right? And so if you do that cycle enough times, then you'll basically end up in a situation where you've substantially minimized the amount of long term waste that you're dealing with because you've actually been able to do multiple irradiation cycles. And this is most plausible in a scenario where you have deployed fast reactor technologies and we could get into kind of some of those dynamics. It would be very difficult to do this somewhat semi infinite loop that I'm describing on our current light water reactor technology. But so that's at least one way that you could manage the long term waste. However, then you do have this fission product waste that you've generated that's nominally for the most part, shorter term. That becomes now a conversation of not trying to manage something on almost an inner civilization basis, but something, okay, we've demonstrated that we have buildings that could last for several hundred years. We've demonstrated these type of architectures. And then you start looking at something kind of like I was saying, much more like fusion in the sense that this is now going to sit around for much less time. You maybe don't need to have a conversation about deep geological disposal. You could maybe start talking about surface disposal of some of these sorts of things, which is something that we're already doing throughout the United States. And then you can even get a step further into this conversation, which is actually potentially even transmuting some of the things that are already much shorter lived. And this is something that ARPA e's been looking at with the Newton program. Many people have considered this. And this is becoming something that's becoming more relevant because of, funny enough, the advances in fusion technology, where particle accelerators and particle generators are becoming much more efficient. And so now the question of needing to build just a. A giant machine, absolutely massive machine, to, you know, generate and irradiate nuclear waste. It doesn't have the same cost profile as it once did. So it seems possible that you could maybe actually minimize some of these sorts of pieces.

B (13:15)

So here's a basic question. How much nuclear waste have we already accumulated in the United States that is currently sitting there lasting either hundreds of years or millions of years? How much is out there?

D (13:27)

Yeah, it's about 90,000 metric tons. We generate about 2,000 metric tons a year. So that's a relatively straightforward answer.

B (13:36)

Okay, and then let's go back to what we had planned to do with it and what we're actually doing with it. So give me the brief history of the planning. You've talked about deep geologic storage in Yucca Mountain, but we haven't actually addressed it directly. What were we supposed to do with it and what are we actually doing with that? 90,000 metric tons.

D (13:52)

Right. So with respect to that, the plan was to put it in Yucca Mountain. This was something that we decided congressionally, decades ago, basically. And, you know, at the time, it made a lot of sense, frankly. You know, there were many things that we were doing within the state of Nevada that connected to nuclear waste nominally. You know, we were also testing a lot of nuclear weapons within the state of Nevada. So the idea, I can imagine how people looked at this and said, oh, maybe disposal of more nuclear waste is not really that far of a stretch when we're already doing these types of activities in Nevada. And over time, there were a lot of different factors that intersected with this. You know, Las Vegas became its own blooming economy. There wasn't this sort of dependent intersection with the Nevada economy with basically with respect to waste disposal. And so I think people looked at this and started to say, do we actually need to take the nuclear waste? What's in it for us? And this has been basically a long standing dynamic where we've seen repeated time and time again with respect to potentially you can have local support for disposal, then you might have a state disconnect with respect to does the state really want to Necessarily take this waste. We've even seen this with respect to lawsuits that we've seen in Texas and New Mexico, where maybe there is a disconnect there, but then there's strong federal support. To get back to the question of what are we actually doing with the waste now. About 2009, there was a decision to stop funding Yucca Mountain. And so we decided that we weren't going to continue to move forward with it. There were a series of lawsuits, actually many of them at the state of Nevada that, that were basically prohibiting really effectively moving forward with respect to waste disposal there. And so we defunded it. And then what ended up happening though is Yucca Mount is still actually the law of the land in the US this is what is in the Nuclear Waste Policy Act. And so we basically have the stasis where we haven't necessarily taken action with respect to what to do with our nuclear waste next, but this is still basically what's our holding pattern. And so as a consequence of that, what's happening with the nuclear waste now, or I should actually correct myself, I don't think about it as nuclear. I think about it as use nuclear fuel. Because there's actually a lot of energy value with respect to that is it is sitting usually proximate to reactors or in consolidated storage facilities. You can imagine if a utility has shut down many reactors that they don't have a reactor potentially to store it next to, so they consolidate it with potentially with other nuclear material they have. And so it's either in some form of basically being stored at a reactor site or at a consolidated storage facility. And then this has other types of concussion effects because the reality is, courtesy of the Nuclear Waste Policy act, there is actually a small fraction of a fee that was paid by anybody in the state where you have nuclear power being produced that went to go and actually pay for what is Yucca Mountain, but might be a future facility at some point. And there's anywhere from about, we'll say about $50 billion within that fee that's been paid forward. Now, since we are formally not proceeding with taking that material off the hands of the utilities, basically there were several lawsuits where the utilities said, hey, you charged our customers for the nuclear waste management. Now we are taking responsibility for this, the guards, gates and guns, security, everything with respect to that. We think that you should actually be reimbursing us for that. And courts agreed with that. And so now there is basically some fraction of the nuclear waste fund that actually goes to pay utilities for the continued man management of that

A (17:35)

what if everyday devices had the potential to strengthen the grid when it's needed most? Energy Hub helps utilities turn that potential into dependable capacity by coordinating thermostats, EVs, batteries and other devices into virtual power plants that respond to grid needs in near real time. Energy Hub's latest white paper lays out a maturity model for VPPs that can be planned and dispatched with the same confidence as conventional plants, while being 40 to 60% less expensive to build. That's why more than 160 utilities across North America partner with Energy Hub to manage over 2.5 million devices that provide 3.4 gigawatts of flexible capacity. Read the white paper and discover what VPPs can do for your grid at energyhub.com Catalyst is brought to you by

C (18:19)

Antenna Group, the OGs of PR and marketing for climate tech. Is your brand a leader or challenger? Are you looking to win the hearts and minds of customers, partners or investors? Are you ramping up your new biz pipeline? Are you looking to influence policy conversations? Antenna works with leading brands across the energy, climate and infrastructure space to do all of this and more. If you're a startup investor, enterprise or innovation ecosystem that's helping drive climate's age of adoption, Antenna Group is ready to power your impact. Visit antennagroup.com to learn more.

A (18:51)

The grid is changing fast. Data centers, electrification and extreme weather are driving a surge in energy demand. Utilities can meet the moment with existing resources by activating energy customers and their distributed energy resources to create predictable and flexible capacity. With Uplight's integrated demand stack, uplight coordinates energy efficiency rates, demand response, and virtual power plant programs into one cohesive strategy to strengthen grid resilience, improve energy affordability, and make progress toward clean energy goals. Learn how Uplight is helping leading utilities harness over 8 gigawatts of flexible load at uplight.com

B (19:34)

I guess the other thing I want to understand is like paint me a picture. What does storage and handling look like for this? Unreal. I mean, you said it's in these solid casks. Like what is the building? What is the facility? What needs to be done in that facility? Is it just inactive of building or is there stuff happening? What does it look like?

D (19:55)

I mean you can go to these sites and see basically there's a couple of different ways that the material is stored. One of them is you have a spent fuel pool and this is where you take the material when it first comes out of the reactor, right? And this is you can imagine the radioactivity of the material dropping off like an exponential as far as just kind of over time. And what's actually funny about what I was talking about, the fission products and the things earlier is that early on those are some of the most toxic and hazardous because they have such a high specific activity. Right. But they just decay quickly away. Right. So you're waiting all of those fission products decay away. You put that in a spent fuel. Both to manage the radioactive hazard of this water is actually a pretty good shield as well as just thermally you're keeping the material cool and all those sorts of pieces. So you let that happen and that happens maybe for a decade or so and then you're in the position where you can take material out and put it in these dry storage casts. Right. And so these casts, they're pretty tall. I'm trying to conceptualize and think about what a good comparator of them would be with respect to width and things of that nature. But you can fit a decent amount of material in there. They're still movable. That you could move them by something like a semi would maybe be a good way of thinking about the scale of them. But that's basically a concrete cask filled with argon. And it's really pretty unremarkable in its way. You can imagine it sitting in a parking lot with the appropriate security and gates and all those things surrounding it. But that's basically how the fuel exists today.

B (21:32)

And from the facility perspective, does it require like you mentioned, trying to keep it cool from a thermal perspective? Do you need N plus 2 backup power supply? Because if you lose power and you can't cool, it's dangerous. Or is it not quite as fickle? Is that like I'm trying to picture, like, is this a thing that's just like a building? You would never. It like, doesn't it really have to get touched? And you don't worry about it because everything after 10 years is in these concrete casks. Or is it like you.

D (22:00)

Do you do want to be able to maintain cooling? Yeah, well, I mean, the concrete cast, once it cools to that point, that's very passive. That is something that you don't need to actively manage. But when it is in its originally cool original cooling capacity, and this is something that can vary a little bit from site to site, frankly, this was one of the challenges that we had with Fukushima was losing the backup power to actually spend fuel pool and circulating that material so that you keep things moving. And so. Right. You can imagine designs on these things have evolved over time based on trying to improve and minimize risk. But early on, it's something that there can be an active component with respect to managing and helping to keep things cool.

B (22:39)

Okay, so that's kind of the state of affairs today, I guess. I'm curious. You mentioned this before when you talked about if we use fast reactors, there's a difference. We, you know, let's assume we have a resurgence of new nuclear power in the United States coming in the next decade or two. There are various types of reactors and various fuels that those reactors use. Talk to me about how much of a difference that either the reactor type or the fuel type makes in terms of the ultimate challenge of handling the waste.

D (23:11)

Yeah, so there are some actually pretty significant impacts with respect to the fuel type. Not so much the reactor type, but the fuel type and the reactor type can be pretty closely coupled. Right. So there are intersections there. And really it boils down to how good of a quote, unquote, waste form the fuel is. Right. So uranium dioxide, ceramic beautiful waste form. You can imagine water gets in contact with your coffee mug. Your coffee mug holds up very well to that. Right. You know, but if you've got a metallic waste form, right. Rust is not such a good thing. Oxidation is not such a good thing. And you can imagine these materials being susceptible to that. Right. So that's something that you have to think about if you have fuel dissolved in a molten salt. Right. So we've seen their molten salt reactor designs with a couple of different. Some of them just use Trisot, again, is a wonderful waste form for all the reasons that people love it as a fuel form. Right. The radioactive material is not getting out when it's reacting in the reactor, and it's not getting out when it's sitting on the side of the building. However, if you're dealing with something that's fuel dissolved in a molten salt. Right. Well, we know that table salt doesn't hold up very well to water. Right. So this would not be a very good waste form. And, and so you end up in a scenario where for especially things like metallic fuels or even fuel dissolved in molten salts that you need to do some form of waste conditioning in order to prepare it for a repository. And some of it can just be that the waste form is not particularly good. Some of it can actually be that some of the elements within it are actually not appropriate for disposal. For example, sodium bonded fuel. Sodium's a RCRA type element. This comes with additional waste management considerations. And ideally you're not putting that in your repository. And this Becomes another piece, piece of why people open up the conversation with fuel recycling as well sometimes for some of these other materials is because if you're just going, if you have to treat and condition the fuel anyways, you're a significant portion of the way there to actually just recycling the material too. And so it seems kind of that is a logical progression from there.

B (25:15)

Okay, so significant differences, as you said, maybe. Can you help me break it down as I think about all the different reactor types that are currently being pursued to, to come, like which ones present the easiest waste handling challenge, which ones present the hardest?

D (25:32)

Right. So anything that is a high temperature gas reactor that nominally uses Triso and there's a lot of these that are in the mix there. Right. That would not be a challenge. Any of your molten salt reactor designs that use a Triso fuel, that would not be a challenge. If you have a molten salt reactor with fuel dissolved in core, that would be potentially something that you need to address and condition and things of that nature. Any of the sodium fast reactor designs. So your TerraPower, your Oklo, things of this nature. This would be a conversation where you need to have at a minimum a waste conditioning component to this. And if you're a company like oklo, that's very much thinking openly about recycling. Right. You're basically moving down that path anyways. And for any of the light water reactor designs that are being considered, like the ge, Hitachi reactor, Westinghouse. Right. That's not advanced reactor Design when the AP1000. Right. We have very established pathways with respect to managing those types of materials.

B (26:28)

I guess. Final question for you. How do you think about microreactors from the perspective of, I mean, setting aside the fuel type. The interesting thing for me is with, with large systems, large projects, you know, you have this repository of, you have your reactor and your whole system and your project to generate power and then alongside that you have this separate, you have these waste storage pools and you have this separate facility that you're going to use to put everything in concrete casks for tens of thousands of years. If you're a microreactor and the whole point is to be really small or remote, how do you think about waste handling for those types of applications?

D (27:07)

Right. And so generally what most microreactor companies pitch is the idea that they can take the entire reactor back. Right. And so you can put that on a truck, ship it back off site, the company will nominally accept response responsibility with respect to waste management and considerations thereof and not pass this on to whoever was, you know, leveraging the reactor to generate power. And so that's been a lot of the conversation with respect to the microreactor space.

B (27:34)

I know that anytime we are looking to move nuclear waste, especially across state lines, it's a big deal. Do you view that as being more palatable in the context of taking an entire reactor back to some centralized storage repository, or is that going to be equally a challenge?

D (27:53)

If a state does not want you to move nuclear material through the state, it will find a way for you to not move nuclear material through the state. And I think this is something that is, I would consider an emergent consideration. The reality is we are, we. There are approaches and there are precedents for people moving nuclear waste use nuclear material from state to state. There are policies in place with respect to how people do this to facilitate transfer of material from a site to a consolidated central storage facility. Whether or not this is something that perhaps if microreactors gain more profile and people have less comfort with that you can end up with, I'll always say that regulatory frameworks are an extrapolation of social license and a formalization of that social license. And so these are things that I think as we continue to evolve in this space, we'll see, see how much there are issues with any that present in this. But at this time, there are precedents for us moving nuclear material around from state to state.

B (29:01)

Final, final question for you. Do are you optimistic about Yucca Mountain 2.0? Are we, do you think that we will end up with a centralized repository in this country? Or is it just in perpetuity? We're just going to store next to wherever the reactor is or in some centralized site that, you know, a micro reactor company needs to ship back to.

D (29:20)

Right. This is something that I think, well, there's a couple of different things that this actually connects to. One of them is that I would be surprised if Nevada ends up stepping forward into this space again. As far as, you know, there's conversations with respect to that being of consideration, etc. I also think that it can be very hard for a given state to accept the entirety of nuclear material for the nation. Right. Without necessarily all the right incentive structures with respect to that. There have been a couple of very nice studies on this. One of them, Hank Jenkinsmith out of the University of Oklahoma has basically done some surveying work asking people, okay, what if we were to just ask you as a state to take on the nuclear waste, nuclear material for the nation, what are your sentiments about that? And it's kind of like not necessarily all that, great, what if we asked you to do this with respect to not only a nuclear repository, but also a recycling facility? And then it's like, oh, okay, we're potentially more interested in that. And then if you have a conversation about, okay, what about nuclear repository, nuclear fuel recycling facility, as well as a national lab or something like that, and then people, there's even stronger social sentiment and interest for that. And so I do think that there is a component of engagement with respect to what are the things that will really encourage people to come to the table with respect to management of this. We have seen this in other countries like Finland, where they have been able to generate the appropriate social structures that will say, yes, we will do this, this makes sense for us, and we'll go ahead and step forward and accept that material as a community for our nation. And so that's one piece of how these things could set up. I could imagine states moving forward and saying, yeah, we're interested in doing this, but we want a recycling facility and we want all the jobs that come along with that. Because then you're not just a repository, you're also an energy provider. And I think that that's a very different narrative. With respect. Another piece to think about is what is the framework with respect to how many repositories are a consideration thereof right now? If Yucca Mountain was opened, we had a legal limit of yucca Mountain of 70,000 metric tons of material, right? So at 90,000 metric tons, Yucca Mount would nominally be full, right? And so you're in a conversation of, okay, where's our next repository to think about? Now people will talk about. About the. That was the. There's a heat limit in Yucca Mountain that was actually above the 70,000 metric ton. That was more like 140,000 metric ton. And so you could have that conversation about, you know, is there any play in that? But I think if you are having a conversation about expanding nuclear technology, and especially if you're seriously thinking about tripling or quadrupling nuclear, you end up in a scenario where you're not actually talking about 2,000 metric tons of material per year, you're Talking about about 6 to 8,000 metric tons of material per year. And this opens up a very different conversation because if you use Yucca Mountain as a heuristic for saying, I don't know, okay, any given repository will hold 80,000 metric tons, then you're in the business of potentially filling up a repository every decade. And that's going to be something, socially, I think that could be a challenge potentially for people to move forward with. And I think this is how you end up in a conversation where if you are able to recycle material, then you could potentially minimize the repository burden and keep yourself more in a regime of one repository. Another thing that's an emerging bit of technology that connects to all of this is at one point we were talking about just exclusively deep geological excavated disposal. People, of course, are now starting to think more and more about borehole related technology. And with respect to disposal of material, there's. And so I can also imagine a scenario where with boreholes, you maybe don't have some of the same geological constraints and considerations with respect to if you're able to just put the material very deep underground. Could you alternatively be in a scenario where, okay, my state is developing and using nuclear energy and I will manage the material for my state? On some level, I almost feel like this could even be a more socially acceptable situation for a state to just manage its own material. But of course, there's broader conversations with respect to this. And this is one of the reasons why, when we were doing and funding recycling R and D, based on the things that I was pointing out earlier. Right. It seems consistently that you can have disconnects at the state level when it comes to nuclear waste disposal. Frequently local communities will be supportive, the federal government will be supportive, and then the state might be not supportive in that regard. And so to the degree that you can engage with state stakeholders at the right moment to make sure that everybody's brought along, I think that's where your solution exists, regardless of what type of disposal strategy it actually ends up being.

B (34:28)

All right, Jen, this was a lot of fun. Thank you so much for taking the time.

D (34:32)

Yeah, no, thank you so much for having me.

B (34:35)

Jen Schaefer is a professor in the Nuclear Science and Engineering Program at the Colorado School of Mines. This show is a production of Latitude Media. You can head over to latitudemedia.com for links to today's topics. Latitude is supported by Prelude Ventures. This episode was produced by Max Savage Levinson Mixing in theme song by Sean Marquand Stephen Lacey is our Executive editor. I'm Shayl Khan and this is Catalyst.