U.S. Approves First Small Nuclear Reactor Design

17:33 minutes

a 3d ariel view rendering of a large oval-shaped complex surrounded by grass, trees, and a river. a road encircles low-lying futuristic-looking buildings in the center, and the complex also includes a small parking lot and two large mirrored teardrop-shaped human-made lakes
A rendering of the NuScale VOYGR SMR power plant. Credit: NuScale Power

Late last month, the U.S. Nuclear Regulatory Commission gave final approval to the first small-modular nuclear reactor design, known in the industry as SMR. It’s not the kind of power plant you might picture when you think of nuclear—gone is the massive cooling tower and tall, domed containment building, in favor of a 15-foot-diameter steel cylinder equipped with passive cooling. 

And instead of being bespoke designs built to order on site, these reactors can be manufactured in a factory and hooked together in the field—an approach that can shave years off the construction time for a new nuclear facility. 

This design, proponents say, could allow straight-forward construction of nuclear plants that replace existing coal-fired power facilities, making use of existing grid infrastructure. Advanced reactors could also be used not just for electricity production, but as a low-carbon means of generating the heat needed for certain industrial and chemical processes. However, any proposed design needs to be safe, reliable, and able to address the persistent issue of long-term nuclear waste. 

Dr. Jose Reyes, co-founder and Chief Technology Officer of NuScale Power, the company behind the recently approved small modular reactor design, and Christine King, director of the Gateway for Accelerated Innovation in Nuclear (GAIN) program at Idaho National Lab, join Ira to discuss the new design, and what the future of nuclear energy might hold.

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Segment Guests

Jose Reyes

Dr. Jose Reyes is the co-founder and Chief Technology Officer at NuScale Power in Oregon.

Christine King

Christine King is the director of the Gateway for Accelerated Innovation in Nuclear (GAIN) at Idaho National Laboratory in Idaho Falls, Idaho.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow.

Last month, the US government okayed the first small-modular nuclear reactor design, SMR as it’s called. It’s a new kind of nuclear power plant. It’s not the kind of plant you might picture when you think nuclear. Gone is that massive cooling tower, in favor of passive cooling. And instead of being bespoke designs, these reactors can be manufactured in a factory and hooked together.

So what does that mean for the use of nuclear energy in the US? Are smaller, more modular power plants the future? Joining me to talk about that are my guests. Dr. Jose Reyes is co-founder and chief technology officer at NuScale Power. That’s the company behind the small-modular reactor design that was just approved by the Nuclear Regulatory Commission. And Christine King. She’s director of the Gateway for Accelerated Innovation in Nuclear at Idaho National Lab. That’s in Idaho Falls. They support R&D for a next generation of nuclear power.

Welcome, both of you, to Science Friday.

JOSE REYES: Thank you. Pleasure to be here.

CHRISTINE KING: The same here. Thank you very much.

IRA FLATOW: You’re both welcome. Jose, tell me about this reactor design, SMR. How small are we talking about? Give me a thumbnail, if you will, please.

JOSE REYES: Sure. Each of the modules will produce about 77 megawatts electric. And physically, it’s about 73 feet in length and about 15 feet in diameter. Now, that includes the containment as well as the reactor vessel. So it’s a very different design in that regard. Instead of the tall concrete containment domes that you typically think of when you look at nuclear power, we’ve gone to a very small steel high-pressure containment vessel, which houses a small reactor vessel. And that whole package is factory manufactured. And like I said, it’s about 15 feet in diameter. So it’s a relatively small cylindrical system.

IRA FLATOW: I see why it’s called modular. Because you make them in the factory and then you might put them together on site.

JOSE REYES: That’s right. Yeah. So we’ve got different design options depending on what the customer wants. A four-module plant would produce about 308 megawatts of electricity. A six-module plant, 462 megawatts electric. And we can go up to a 12-module plant, which will produce 924 megawatts. So almost a gigawatt class-size plant.

IRA FLATOW: Now, I don’t have to tell you that, historically, nuclear power plants take many years to build. Does your design speed up this process at all?

JOSE REYES: It does. And so what we’ve done by going to factory manufacturing, we’ve significantly reduced construction time. So while you’re doing all your civil construction on site, in parallel, you’re doing all your high-quality manufacturing in a factory. This takes us down from a five-year schedule to about a three-year schedule just by doing this in parallel.

IRA FLATOW: And who’s this designed for? Is this going to replace something my power company would have, or is it smaller than that?

JOSE REYES: We size it with the customers in mind. And gosh, since 2008, we’ve been talking to about 28 utilities in the US and Canada. And we kept hearing two things. They said, we have aging coal-fired plants that need to be replaced. We’d like to replace them with clean energy. And we also have the need for grid stability. We have a lot of renewables. We need something to stabilize the grid. So we sized our plants with that in mind. And so we’re getting a lot of interest globally for coal-fired plant replacements in this size range.

IRA FLATOW: As someone who spent a couple of weeks at Three Mile Island in 1979, I am fascinated by no cooling towers, passively cooled. Tell me how that works.

JOSE REYES: Yeah. The secret is in it being small. So in this design, under the worst-case conditions, the reactors will shut themselves down without any operator or computer action, without the need for AC or DC power. And they’ll remain cool for an unlimited period of time without the need to add water. So this is a big breakthrough for commercial nuclear power. It hasn’t been done before. But now it’s approved by the Nuclear Regulatory Commission.

IRA FLATOW: Christine King, you have your finger on all kinds of reactors. What are some of the other possibilities out there? And how does Jose’s reactor fit into this picture?

CHRISTINE KING: So Jose’s reactor is an advancement on the existing fleet that we have. So he’s continuing to use the light water reactor technology– light water being a reference to the coolant that takes away the heat from the nuclear reaction itself. But there’s about two dozen companies working on different advanced reactor technologies. And there’s a variety of different sizes, designs, coolants associated with that.

So right now, the things that are under development span from microreactors, producing less than 50 megawatts electric, to medium-sized reactors in that 300 to 600-megawatt electric sizes. And similar to what Jose was mentioning, this is about tailoring the technology to meet the changing energy system.

The other aspect of these new designs is that we will do more than produce electricity. So a lot of our industrial partners rely on high-temperature process heat from fossil fuels, either coal or natural gas. And to decarbonize and give them clean energy, you need something that can operate in that same temperature range. So some of these other designs will operate at a higher temperature than what the NuScale design does.

IRA FLATOW: And the advantage of that is what?

CHRISTINE KING: Well, the advantage of that is, when you have renewables available, you can actually use your nuclear reactor to produce process heat. You might use that heat to drive high-temperature electrolysis to produce hydrogen and other synthetic fuels to support a clean economy. Or you might use that as a direct input to build close to load. So we’re talking about producing more than electricity with this new class of reactors.

IRA FLATOW: They used to say that nuclear reactors were the most expensive way to boil water because you’re creating steam to drive a turbine. And I hear what you’re saying is that’s different. And Jose, you’re laughing at that.

JOSE REYES: Yeah. No– I mean, that story has been around for a long time. We typically think of nuclear power as producing steam and being a baseload technology. But this new generation of reactors is really looking to be more flexible for the modern grid. And so, as Christine said, you’re looking at hydrogen production. So we currently have a study ongoing with Shell Global. And they’re looking at hydrogen production as a possibility for energy storage as well as for a commodity to sell.

But we’re also looking specifically at something we call the energy imbalance market. We have a lot of renewables, and you need to store some of that energy during the day and then release it in the form of electricity in the evenings, when renewables may not be available. So it’s a very different dynamic that’s occurring for this modern grid. And we’re excited to be part of that.

In one study we did with Idaho National Lab, one of our modules coupled to this high-temperature steam electrolysis could produce almost 50 tons of hydrogen per day. And we’re also looking at desalination. That’s the next big issue that we’re working on. One module produced about 77 million gallons of clean water today. So the opportunities are really endless.

IRA FLATOW: Christine, you mentioned this being a light water reactor. What about other reactors with different cooling approaches, like gas or even liquid metal, like sodium?

CHRISTINE KING: Yeah. So actually there’s two full-scale demonstration projects underway that are building out those technologies and will be operational in the latter part of the 2030s, 2027 and 2030. The Natrium reactor is a sodium-cooled fast reactor that is paired with a molten salt-based energy storage system to do exactly what Jose was mentioning– the ability to peak in the evening, such that you have the power that you need as the sun goes down and the renewables are not available.

This project is being built in Wyoming by TerraPower, and it’s being built adjacent to a coal station. And there’s a lot of good things associated with those particular choices. One, you have that infrastructure to connect to the grid. You also have the workforce from the coal station. So in terms of an energy justice perspective, for those people that have given us reliable power for a hundred years from our fossil fuel plants, nuclear is a way for them to have another career.

The other project that’s under development and co-funded by the DOE is the X-energy Xe-100. And this is a high-temperature gas reactor using TRISO fuel.

IRA FLATOW: Using what?

CHRISTINE KING: TRI-structural ISOtropic particle fuel. Essentially, it is a particle of uranium that’s encapsulated in three layers of carbon and ceramic coating. And so that particle, in and of itself, is a new fuel form. And those layers prevent the radioactive fission products from being released. So the particle itself acts as its own containment.

IRA FLATOW: You have anticipated my next question. Because I can see my email exploding now, asking, what about radioactive nuclear waste disposal, theft, or terrorist attacks? Jose, how do you answer those points?

JOSE REYES: Yeah. So certainly, early on in these programs, you do a safeguards assessment. And that’s something that we’ve done– two assessments with the Pacific Northwest National Laboratory. And we’ve also been working with the International Atomic Energy Agency. The conclusions of those studies was that these reactors, because they’re low-enriched, really don’t present a threat from the standpoint of terrorism or nonproliferation.

In terms of the waste that’s produced, we’re talking about very small quantities of used fuel. For our design, for example– the one that we’re building in Idaho– that’s a six-module plant. For 60 years of operation with that plant, all the used fuel that’s generated could be stored on 0.8 acres of land. So it’s a very small amount of waste that’s being generated from these plants. And that’s over a very long period of time. And the storage is on a very small footprint.

IRA FLATOW: But yet, again, Christine, we haven’t got a permanent storage solution– a central storage solution yet, do we?

CHRISTINE KING: No, sir, we do not. However, the DOE does have active work underway to pursue consent-based siting to look at a central storage solution. I think another exciting aspect of waste for the advanced reactors is the opportunity to recycle the waste from our existing fleet for the fuel for some of these new reactors, as well.

ARPA-E has funded some work to look at the technologies necessary for recycling. And having a centralized facility, where you’re bringing all of our spent fuel together would also be an excellent enabler for a recycling process. Other countries do recycle their spent fuel. They have what’s called a closed-fuel cycle. So we would need to make that decision that we wanted to have a closed-fuel cycle, and then enable the infrastructure by which to do that. But it does start, I believe, with a consolidated facility.

So in the near term, our advanced reactor developers and those buyers of these reactors will need to plan for on-site storage, similar to what we do today with our nuclear waste.

IRA FLATOW: This is Science Friday, from WNYC Studios.

Are there any radical new designs that are waiting to be finished, or testing, or something that we just never thought about before?

CHRISTINE KING: I think one of the more interesting aspects of the class of reactors coming out today are truly in these smaller reactors, these microreactors. And we will see two of them operational by 2025. The Department of Defense, through Project PELE, is looking at having a fully transportable small reactor to support their operations.

The state of Alaska is looking at how a microreactor might help with some of the more remote communities in Alaska, and how to provide them reliable power. I think that is an exciting aspect of what’s going on– I also think these medium-sized reactors and being able to support the decarbonization of our industrial sector.

I think we understand, in a lot of the decarbonization plans, how electricity plays a role. But as a chemical engineer, if I had a highly-tuned chemical process for producing a polymer, so to speak, I don’t think I’d really want to change my process incredibly. I just would like to get the same amount of energy I had before, it just coming from a clean source.

IRA FLATOW: How do you get past the NIMBY part of this, not in my backyard? I think it’s a great idea, but, Jose, I don’t want this one in my backyard. How did you deal with that in Idaho in the new project?

JOSE REYES: Yeah, it’s really a community-based outreach that has to happen. And I think there were over 120 meetings with the community, in terms of town halls and opportunities for the city councils to examine what we were doing and to understand the process that was ahead of them. What was great about those outreach was it also shared what are the different energy options, why is it important to go green in terms of clean energy sources. So I think those outreaches are very, very important. And that’s something that UAMPS in particular has spearheaded, working with NuScale for that first project in Idaho.

IRA FLATOW: So you have the OK to go ahead. When might we see the actual operation? Are you talking three to five years– as you mentioned before– about three years?

JOSE REYES: Yeah. So we’ve got the next steps. Basically, the owner, UAMPS, will be applying for the site permit, the construction operating license application approval. So that’s going at the end of this year. That’s a two-year review. And then, in 2025, when that’s approved, construction could begin at that point. So that’s a three-year build from that point. So we’re looking at sometime in the end of 2029 to get those first modules delivered, and fully operational, all six modules, by 2030.

IRA FLATOW: Christine, what about extending the lifetime of existing installations? I know that– I think it was– Diablo Canyon, in California, was set to go out of business, and now they’ve extended the life of it. Do you think we’ll see more of a trend this way?

CHRISTINE KING: Actually, we already are. So today, we have 92 reactors operating in the United States at 53 different sites. Only 10% of those still have a 40-year license, which is the original license you would have on a nuclear station. 65% of them have already extended their life to 60 years.

Now, if we don’t extend those licenses to 80 years, we will see those plants come offline in the 2040s. And that’s about 60 gigawatts of power. It is important for us to extend that fleet to give us what I would call ramp into the 2060s. We already have six plants with approval to operate to 80 years, and 15 more have either submitted an application to extend or are expected to apply soon.

IRA FLATOW: People are going to be worried about a plant that’s 80 years old.

JOSE REYES: Well, I tend to think about the process of license renewal similar to the process of those milestone birthdays we all have and those doctor visits, where the doctor looks at your own history and looks at your family history, and in some cases, just generally recommends that you do some inspections so that we make sure we understand how to manage you going forward.

Doctors recommend colonoscopies for people when they turn 50. But if you have a family history, they may ask you to do that earlier, and you may need to do that more frequently. Managing the life extension of your nuclear plant is similar to managing your own personal life extension with your doctor.

IRA FLATOW: Well, it’s interesting that you’ve compared nuclear power to colonoscopy.

CHRISTINE KING: Well, hopefully, I don’t go viral for that.


IRA FLATOW: I want to thank both of you for taking time to be with me today. Jose Reyes is co-founder and chief technology officer at NuScale Power, based in Oregon. Christine King, she’s the director of the Gateway for Accelerated Innovation in Nuclear. That’s at Idaho National Laboratory, in Idaho Falls, Idaho. Thank you, both, for taking time to be with us today.


JOSE REYES: Thank you.

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