Olivia Columbus [00:00:58] We are here today with Sander de Groot, who is the CTO and co-founder of Thorizon. Sander, welcome to Titans of Nuclear. 

Sander de Groot [00:01:05] Thank you. 

Olivia Columbus [00:01:06] So Sander, how did you originally get into the nuclear industry? 

Sander de Groot [00:01:10] So, I graduated as a mechanical engineer, and after a short while in an engineering company, I moved to NRG. NRG is a nuclear research organization and medical isotope producer in the Netherlands and operator of High Flux Reactor in Petten. I've been working there since 2000, for over 22 years. 

Sander de Groot [00:01:27] And in the last few years at NRG, I initiated the molten salt reactor program at NRG. Molten salt reactors became very popular in that period. Of course, these reactors have been operated in the '50s, and after that, basically stopped any developments in this field. But I thought the technology was hugely interesting. So I decided, "Let's initiate a program at NRG."

Sander de Groot [00:01:52] Within that program, an idea emerged for a molten salt reactor, to design and build it in certain way. And within NRG, there was not really a possibility to develop this further, so with the agreement of NRG, we started Thorizon and picked up that concept. We developed it further in my own time, at my own risk, with a number of people who were interested in this. We submitted the patents, got in contact with nuclear industry parties, for example, Orano, which is a major partner for us. And then, we got in contact with investors and we closed a financing round last year's summer. And since then, I'm full time working for Thorizon. 

Olivia Columbus [00:02:38] Very exciting. We will dive into all of that in just a moment, but I want to talk a little bit more about NRG and the work you did there. So just for our audience who may be less familiar with NRG... The Dutch NRG, because there is another NRG which is completely separate. They operate the PALLAS Reactor, which the high-temperature flux reactor in the Netherlands. They also provide other support for organizations in terms of things like licensing, is that correct? 

Sander de Groot [00:03:05] Yes, yes. 

Olivia Columbus [00:03:09] Did you work at all on the PALLAS Reactor or were you just very specifically focused on the molten salt program? 

Sander de Groot [00:03:13] No, when I started to work, I was working in this consultancy department of energy. So, I was in the computational engineering field doing structural mechanic analysis, fracture mechanics, safety analysis, and also designed facilities that were put in the High Flux Reactor. And after that, I moved to more project management of irradiations. So, fuel material, irradiations in the High Flux Reactor. And I was a lot involved in high-temperature reactors, basically, at that time. And after that, moved more into the business development side. And from that position, I initiated the molten salt reactor program. 

Olivia Columbus [00:03:47] Got it. And so, you guys are doing a lot of the medical isotopes, is that correct? Are they primarily for the Netherlands? Are you guys producing them broadly across Europe? I know in the United States, Canada produces quite a few of our medical isotopes. Are you guys sort of doing that same support in Europe? 

Sander de Groot [00:04:04] Yes. Well, NRG is basically providing 30% of the world demand. So, it's a lot.

Olivia Columbus [00:04:10] Wow. That's really interesting because I know that the Netherlands has, obviously, a fabulous nuclear regulator and nuclear history, but they only have one commercial operating reactor right now. We just had Carlo Wolters on the podcast recently. 

Sander de Groot [00:04:27] Ah, okay. Yes. 

Olivia Columbus [00:04:27] I think he was last week's episode. So, that was wonderful. Carlos from EPZ, for anyone who's not familiar, which is the the nuclear utility in the Netherlands. And then, is the PALLAS Reactor the only other research facility or are there other research reactors in the country as well? 

Sander de Groot [00:04:45] PALLAS is basically a reactor that is currently being constructed. So, it's a replacement of the High Flux Reactor, which is the existing material test reactor and medical isotope production facility. So, yeah, it's a replacement; that's what PALLAS is. 

Olivia Columbus [00:04:59] But that's the only other research reactor in the Netherlands, or do you have others? 

Sander de Groot [00:05:02] There's also a smaller university research reactor at Delft University. 

Olivia Columbus [00:05:07] Got it. Okay, interesting. Interesting. Well, hopefully we see more commercially operating reactors come online soon in the Netherlands. 

Sander de Groot [00:05:13] Yeah, of course. Carlo has a lot of ambitions, and that's wholeheartedly supported. I think we need it.

Olivia Columbus [00:05:18] Yes, absolutely. Yes. So, back to Thorizon and the work you're doing there. It's a molten salt reactor, right. And about how big is it? 

Sander de Groot [00:05:30] The size that we're currently focused on is 250 megawatt thermal. And with that, we can produce 250 megawatts of steam, which can be then converted into electricity, about 100 megawatts electric. 

Olivia Columbus [00:05:41] Okay, so about 100 megawatts. How large of a plot size are you targeting? 

Sander de Groot [00:05:47] Well, we are currently looking at that. Generally, the core is really compact, so it's not that big. So, let's say that the nuclear island should be 30 to 30 meters type of square. But then of course, the turbine island and anything connected to it. But what we are looking at is that the core is this reactor, of course, and then you can connect to many types of different processes that are connected to. For example, so investigating that the energy that's produced is stored in salt. 

Olivia Columbus [00:06:18] Oh, right. Yes. 

Sander de Groot [00:06:18] So, our primary system is salt. The secondary system is salt. We can connect to a tertiary cycle of salt where we can store energy. And then in that sense, with all the renewable energies coming up, we can compensate and make use of the flow in demand and supply. 

Olivia Columbus [00:06:34] And so, are you guys just designing the reactor system? And then, would you partner with a company like a Malta or something who are doing those storage systems, or are you guys also looking to develop the additional systems as well? 

Sander de Groot [00:06:47] I mean, we're a startup company. So, to be able to build a reactor like that you need thousands of people and we want to do it quickly. So, you cannot do that by just growing as a startup company. At least, we think that is unreasonable. So, what we're trying to do is to team up with partners that have the expertise and people to grow really quick. So typically for something like this, which is outside of the nuclear island, we would team up with somebody else. And also, within the nuclear island we are looking for partnerships within nuclear industry to speed up our progress and accelerate as much as we can. 

Olivia Columbus [00:07:18] Absolutely. So, have you built any of those partnerships that you can publicly announce yet? 

Sander de Groot [00:07:22] Well, one of the partnerships that we are working with is Orano. And that's a very important one because we were looking at the reactor, and Orano's particularly interested in molten salt fuel production and also taking molten salt fuel back after use and incorporating that into their reprocessing facilities. So, that is really important because it takes away our concerns in producing the fuel and we can focus on our reactor design. So, that is a very important partnership. 

Olivia Columbus [00:07:49] Yeah. And so, are you targeting initial deployment in the Netherlands or are you looking at a lot of different markets? Where are you looking to build your first facility? 

Sander de Groot [00:08:29] We're looking at everything, and then we move with the wave. So, where is the largest interest? So, we're talking to Carlo as well and EPZ. They have a very large site with a nuclear destination, and we're also discussing with them, "Is your site not interesting for a system like ours?" And they're interested, but of course, we're not in any committing stage at the moment. 

Sander de Groot [00:08:49] But for them, with the ambitions to build light-water reactors, they also have concern about how to manage the fuel cycle, how to manage the waste streams that come from it. And our reactor is particularly suited to be able to take the long-lived elements out of spent fuel, using it as a fuel, and in the meantime, reducing all the long-lived waste streams that could come from light-water reactor operation. 

Olivia Columbus [00:09:10] Absolutely. Well, that's very exciting. And so, what types of customers... I mean, you mentioned storage as an option, but are you guys looking to deploy at a grid scale or are you guys thinking that you'll have industrial behind the meter customers? What are you looking at for your early deployment? 

Sander de Groot [00:09:30] Basically, what we try to do is to have that reactor operating as long as possible just to keep the economy high. So, one of the customers that could be interesting is an industrial end user that basically needs a 24/7 supply of heat. That's one of the customer directions that we're looking into. And it's the easiest one, because heat is what we produce in any case. If we produce electricity, that can also be used for a certain site, especially if industry starts to electrify hydrogen production, for example. Then, we could also support that 24/7. 

Sander de Groot [00:10:00] If we come to more like the grid, grid stability or customers that have fluctuating demand in combination with the fluctuating supply from renewables, then you come into this idea of keeping a reactor operating continuously but store the heat and use it when the demand is there. So, we're looking at all these options, basically. But the core of the system doesn't change because of that. We're stuck to the 250 megawatt thermal. It's based on our technology. This is what we think we can maximally achieve in a reasonable way, and we stick to that. 

Olivia Columbus [00:10:36] Yeah, absolutely. The Netherlands is interesting geographically because you have some neighbors that are not big fans of nuclear, especially Germany being the biggest one; Belgium as well. What challenges does that pose? But also, what opportunities are there to provide energy generated in the Netherlands to countries that do not have clean baseload power? 

Sander de Groot [00:11:03] Well, at the moment, politically, it's of course a complication. Like, Germany is really anti-nuclear and sticking on that route, so they have influence on European frameworks, on how to implement. So, it's not something that we are actively trying to change. We can't, and it doesn't help the European framework for nuclear. 

Sander de Groot [00:11:24] So we connect to France, we connect to Orano, and we have also set up an office in Lyon to strengthen this relation and make sure that we make the most out of what is present in the Netherlands and in France to accelerate our development. But we're basically not having any ambitions to start talking in Germany and try to convince them that this is really good idea. 

Olivia Columbus [00:11:47] Yeah, absolutely. And how many team members do you guys have at this point? How large is your team? 

Sander de Groot [00:11:54] We're now with 20 people in Amsterdam, and we have hired 5 people in Lyon. And we are continuously to hire. We aim for having also a 20 person team in Lyon and grow from there. So, every opportunity we can get to accelerate our program and our development, we try to pick up. 

Olivia Columbus [00:12:15] Absolutely, absolutely. Well, we like to finish these off by looking at the future, so I want to give you the opportunity to talk about what you see as the future of nuclear and where you see nuclear energy playing a role in the global energy mix going forward. 

Sander de Groot [00:12:36] Well, I think the challenges of this energy transition are so enormous that without nuclear energy, this will not work. And we also need to be quick about it. That also means that a development like what we are doing will take too long. So, we need to establish light-water reactors which are off the shelf. Build them, please, everywhere you can; we need it. And for many reasons. It's climate, it's independence, it's emissions. It's just something that you should do. 

Sander de Groot [00:13:08] Complementary to that... And this is also how we basically position ourselves. We also need to take the responsibility in the nuclear sector to look at the waste streams, to look at how do you use your resources effectively. And I think molten salt is the ultimate technology that can make the most out of nuclear materials. Both in reduction of waste, long-lived waste, and in getting the most energy out of these resources that we have. So, I see this complementary role. 

Sander de Groot [00:13:35] And with molten salt reactor technology, there are many ways you can develop this technology. You can look at moderated system, you can look at fast spectrum systems. And it's all based on molten salt. So, once we have those systems operational, I think there's a very large future for this. But as said, complement to light-water reactors. 

Olivia Columbus [00:13:56] Absolutely. Sander de Groot, thank you very much for joining us on Titans of Nuclear. 

Sander de Groot [00:13:59] Thank you.