Deep Fission CEO Liz Muller on New, Underground Nuclear Reactors

Summary

Bloomberg Businessweek: Deep Fission CEO Liz Muller on New, Underground Nuclear Reactors

Date: June 22, 2026
Host(s): Carol Massar, Tim Stenovec
Guests: Liz Muller (Co-founder & CEO, Deep Vision/Fission), Will Wade (Bloomberg News Energy Reporter)

Episode Overview

This episode centers on the transformative potential of Deep Vision’s underground modular nuclear reactors, featuring an in-depth interview with CEO Liz Muller. The discussion covers how Deep Vision is advancing nuclear deployment by combining proven pressurized water reactor tech with deep borehole drilling, positioning the company to quickly supply clean energy—particularly for the rapidly growing AI and data center sectors. The conversation also touches on going public, project timelines, market challenges, public perceptions, and the future of nuclear’s role in the U.S. energy mix.

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Key Discussion Points & Insights

The Deep Vision Model: Why Nuclear, Why Underground?

[02:35–03:43]

• Liz Muller: Deep Vision uses “currently available advanced reactor technology” (pressurized water reactors) in a “borehole a mile underground,” enabling “much faster” and “significantly lower cost” deployment compared to traditional, above-ground reactors.
• Core Rationale: Underground siting leverages natural rock structures and uses a mile-long water column for pressure—eliminating the need for expensive and time-consuming above-ground containment structures.

“When you deploy it in a borehole a mile underground, you can deploy it much faster. You don’t have all the construction that you, you would have for a conventional above ground nuclear reactor.”
— Liz Muller [02:37]

What Problems Does Underground Deployment Solve?

[03:03–04:42]

• Construction Complexity: Traditional nuclear projects are “too expensive” due to complex, massive constructions.
• Underground Solution: The rock and water column provide inherent containment and pressure, reducing the need for costly systems—lowering both cost and time to deployment.

“You’re able to take advantage of a column of water above you in the borehole that is creating pressure through the force of gravity...we’re much lower cost and much faster in order to build.”
— Liz Muller [03:13]

Using Proven Technology in Novel Ways

[04:05–05:50]

• Deep Vision leverages standard pressurized water reactor technology and “standard commercially available fuel,” combined with deep borehole drilling.
• Muller emphasizes this is not speculative tech: “This is using proven technology that already exists...combining that with deep borehole drilling.”
• Safety Profile: Already safe above ground, but “when you put it a mile below ground the safety profile is extraordinary.”

“When you put it in a reactor a mile below ground, the safety profile is extraordinary.”
— Liz Muller [04:23]

• Public/Expert Reactions: Responses are mixed at first—“a little bit of disbelief”—but the safety and engineering advantages start to win people over.

“It does start off with a little bit of disbelief. Why are we the only reactor company that is taking this approach...But the more people start to understand what we’re doing and that we’re using existing proven technologies, the more people start to appreciate the benefits.”
— Liz Muller [05:00]

Faster, Cheaper, and More Predictable Builds

[05:50–06:46]

• Time & Cost Savings: Conventional containment domes take “years to construct...where you can have significant cost overruns.” Deep borehole drilling “you measure in weeks, not years.”
• Schedule Reliability: Underground deployment reduces project risk and accelerates the path to operation.

“That drilling time, you measure it in weeks, not years. And so it’s really a much, much faster build time.”
— Liz Muller [06:10]

Project Status, Scale, and Roadmap

[06:46–07:55]

• First Project: Construction underway in Parsons, Kansas, as part of a Department of Energy pilot, enabling faster-than-normal regulatory progress.
• Timeline: First deployment for grid connection targeted for “late 2027 or early 2028.”
• Commercial Vision: The Kansas pilot is not just a test but intended for commercial power generation soon after demonstration.

“We are targeting late 2027 or early 2028 for that first deployment and putting electricity onto the grid.”
— Liz Muller [07:14]

Competing in a New IPO Environment

[08:29–09:52]

• IPO Details: Originally aimed for $150M at ~$25/share, but IPO executed at $16/share, raising ~$40M.
• Next Milestone: Funds will go towards “commercial borehole proof of concept”—showing the drilling and emplacement work at scale by fall.

“Our big milestone is the commercial borehole proof of concept, which we are looking to do this fall...proving out that we can build the borehole to our specifications...”
— Liz Muller [09:03]

Demand: Data Centers, AI, and Growth Markets

[09:52–10:47]

• Surging demand for electricity driven by “AI and data centers”—with Deep Vision seeing “15 gigawatts of allies” (customers in queue), “more than half of that from data center developer companies.”
• Competitive Edge: Speed to market (2028–2029 installations) is compelling for customers who can’t afford to “wait into the 2030s.”

“We’ve got 15 gigawatts of allies for Deep Vision reactors...more than half of that is from data center developer companies...our ability to meet that demand and do it quickly...is much more attractive than having to wait into the 2030s.”
— Liz Muller [10:05]

Public Perception and Community Response

[10:47–11:23]

• Community Attitudes: Initial surprise evolves into “really excited” as residents and stakeholders learn more about speed, safety, and proven technology roots.
• Messaging Challenge: “The first response is, well, why are you doing it a mile underground? But...I think people start to get really excited about our ability to get this done and to get it done quickly.”

The Future of Nuclear in the U.S. Energy Mix

[11:23–12:15]

• Nuclear currently supplies about “20%” of U.S. power, and Liz sees that as likely to at least hold, possibly rise, “because we need all the electricity that we can get...”
• Energy Security: Urgent need for new builds to support AI, grid stability, climate, and U.S. leadership.

“While a few years ago people were talking more about energy transition...what we have right now is we just need to build, we need to make sure that we remain the leaders when it comes to not just AI, but also the production of energy and nuclear can help us get there.”
— Liz Muller [11:45]

---

Notable Quotes & Memorable Moments

• On Safety Underground:
  “When you put it in a reactor a mile below ground, the safety profile is extraordinary.” — Liz Muller [04:23]

• On Industry Perception:
  “It does start off with a little bit of disbelief...But the more people start to understand...the more people start to appreciate the benefits.” — Liz Muller [05:00]

• On Speed:
  “That drilling time, you measure it in weeks, not years.” — Liz Muller [06:10]

• On Demand:
  “More than half of that [demand] is from data center developer companies.” — Liz Muller [10:08]

• On the Urgency of Electrification:
  “What we have right now is we just need to build...nuclear can help us get there.” — Liz Muller [11:45]

---

Timestamps of Important Segments

• [02:35] — Elevator pitch: Why Deep Vision’s model is different
• [03:13] — What putting reactors underground solves
• [04:05] — Using proven technology in a novel way
• [05:00] — Public and expert reactions, initial skepticism
• [06:00] — Project cost, speed, and predictable schedules
• [06:59] — Project status: where, when, and DOE pilot details
• [07:55] — How Deep Vision is moving faster than competitors
• [08:29] — IPO outcome and its implications
• [09:52] — Demand drivers: data centers and AI impact
• [10:47] — Community reactions and public response
• [11:23] — Longer-term vision: nuclear’s U.S. energy share and urgent need

---

Conclusion

Liz Muller provided a compelling look at how Deep Vision’s underground nuclear reactors aim to rapidly increase clean electricity supply—especially for the booming AI/data center economy—by leveraging proven technologies in a novel deep-borehole format. The approach promises faster, safer, and more cost-effective nuclear builds, with strong early demand. Despite IPO market challenges and initial public skepticism, Deep Vision positions itself at the intersection of energy innovation and infrastructure urgency, creating a possible template for the future of American clean power.

Transcript

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[Bloomberg Host Carol Massar]

You're listening to Bloomberg businessweek with Carol

[Liz Mueller]

Massar and Tim Stanvik on Bloomberg Radio.

[Interviewer Tim Stanvik]

We can't talk about artificial intelligence without talking about the energy that you need to power the AI build out. Isabel Growing electricity demand for from AI and data centers is prompting a global need for different forms of energy. One company seeking to meet that need is Deep Vision. It's an advanced nuclear energy company developing small modular pressurized water reactors installed one mile underground. We're going to learn what all of this means. The company began trading on the nasdaq priced at $16 per share under the ticker FISN. Pleased to say we're now joined by Liz Mueller, co founder and CEO of Deep Vision. She joins us from our San Francisco bureau. We're also joined by Will Wade, Bloomberg News energy reporter here with us back in New York. But Liz, let's start with you. Just give us the elevator pitch for Deep Vision. What is the company and why did you guys go public now?

[Liz Mueller]

Yeah, Deep Vision, as you noted, is a different deployment model using currently available advanced reactor technology. So pressurized water reactors are the most common type of nuclear reactor we have today. But when you deploy it in a borehole a mile underground, you can deploy it Much faster. You don't have all the construction that you, you would have for a conventional above ground nuclear reactor. And so you can build it faster and at a significantly lower cost.

[Interviewer Will Wade]

So for viewers just hearing about this, what problem does putting reactors a mile underground actually solve in nuclear deployment today?

[Liz Mueller]

Yeah, it's really two issues. The first one is nuclear has historically been too expensive. There's just too much construction, too many parts that need to get built. When you build it underground, you're able to take advantage of the rock that already exists. You're able to take advantage of a column of water above you in the borehole that is creating pressure through the force of gravity. And so you don't need big expensive pressurizers. And so the result is we're much lower cost and we're much faster in order to build.

[Interviewer Tim Stanvik]

So, Liz, what I kind of like about your company is that it's taking existing technologies that we already have. We know how to dig holes, we know how to build reactors, and, and it puts them together in a way that nobody's done before. You haven't done it before either. Of course. It's still new. We're waiting to see it happen. But can you talk a little bit more about how that can save money?

[Liz Mueller]

Yeah. So you're exactly right. This is using proven technology that already exists. So pressurized water reactor technology and standard commercially available fuel. But combining that with deep borehole drilling, which is also something that is commercially available and we know how to do. And when you combine those two, that's where you get something really special. And a different deployment model. Nuclear is already very safe above ground, but when you put it in a reactor a mile below ground, the safety profile is extraordinary. And that means that you can take out a lot of the cost as well as a lot of the time to build.

[Interviewer Tim Stanvik]

It's an interesting idea. What sort of reaction have you had since you came up with this idea? Because I feel like it can go two ways. You can get people saying, oh my God, that's crazy. I've never heard of anything like this. Or you can get people saying, oh my God, I've never heard of anything like this. What a brilliant idea.

[Liz Mueller]

Yeah, I think we get both. So I think it does start off with a little bit of disbelief. Why are we the only reactor company that is taking this approach and doing something so different, which is building a mile underground? But then the more people start to understand what we're doing and that we're using existing proven technologies, the more people start to appreciate the Benefits of being surrounded by billions of tons of rock so that nothing can get out of the borehole. Having that column of water that is a mile long above you in the borehole, that is creating the pressure on your reactor. But it's also your emergency core cooling system. And when you're a mile underground, there's nowhere for that water to go. And so the safety profile, I think, also grows on people as they start to appreciate the differences and the benefits of building a reactor a mile underground.

[Interviewer Will Wade]

So, Liz, nuclear projects are known for delays and cost overruns. Why does this, why does going underground make execution easier rather than more complicated, in your view?

[Liz Mueller]

Yeah. I'll give you an example of the containment structure. So typically for above ground nuclear. Nuclear power, you require a containment structure to make sure that nothing gets out into the environment. And that can take years to construct. And because it's all quality maintained, there's maintenance required, you need to make sure there's no degradation. So that can be where you can have significant cost cost overruns and delays in schedule. But when we're doing it, we're drilling for that equivalent containment underground. And that drilling time, you measure it in weeks, not years. And so it's really a much, much faster build time to get something like the containment dome. And then it's similar for other parts of the reactor.

[Interviewer Tim Stanvik]

Liz, give us a sense of scale so far. How many reactors do you have? What regions in the country are they currently deployed in and then plans for maybe future future projects?

[Liz Mueller]

Yeah, so we are building our first reactor right now in Parsons, Kansas, and we're able to participate in the Department of Energy reactor pilot program, which is allowing us to build a reactor faster than we otherwise would have been able to do. Now, importantly, as part of this program, we are actually deploying a few first commercial reactor. So it is a test reactor under the Department of Energy program, but our intent is once we've built it, to then use it for the commercial generation of electricity. And we are targeting late 2027 or early 2028 for that first deployment and putting electricity onto the grid.

[Interviewer Tim Stanvik]

2027, 2028 for a new commercial nuclear power plant. That's just really fast. I'm amazed to hear you say that. There's so many other companies that are working and they don't have schedules anywhere near that fast. What can you. How can you do this faster than they can do it?

[Liz Mueller]

Yeah. Again, this is when we're able to leverage technology that has already been proven and that is well understood and is even commercially available. So we don't need to build a manufacturing facility or a fuel fabrication facility. We're able to go so straight to building the reactor itself using dozens of commercial vendors who can, who can build to our specifications. So that means that we can deploy within these timeframes. Again, it's proven technology and we're just able to change the deployment model so that we can get it built faster.

[Interviewer Tim Stanvik]

Can we talk a little bit about the market reaction that you've had? I know you were trying to get this IPO out the door a few weeks ago and that was aiming for about $150 million at a 24 to $26 valuation. Today we saw that it was actually closer to $40 million and the pricing was closer to 16. And today it's even down just a little bit. So what does that say about how the world sees you?

[Liz Mueller]

Yeah, I mean, what I think is we price this, this IPO to give most, most possible investor confidence and we are going to be able to reach that next milestone. Our big milestone is the commercial borehole. Commercial borehole proof of concept, which we are looking to do this fall. And that's a significant milestone because we are going to be proving out that we can build the borehole to our specifications, that we can emplace a non nuclear reactor in that borehole, that we can get the sensors down there and that we can see start to measure the heat generation and all of these things that are new when it's in a different environment. So even though we're using the proven technology, the deployment model is something that we can prove out. And the 40 million that we're raising now is enough compared to combined with the 60 million that we raised previously to reach this next milestone.

[Interviewer Will Wade]

Liz, how dependent is your story on the surging demand for AI and data centers when it comes to the future growth of your company?

[Liz Mueller]

Yeah, we're definitely seeing demand from data centers and for AI. So we've got 15 gigawatts of allies for Deep Vision reactors. That's very strong demand. I would say that probably more than half of that is from data center developer companies. So these are the groups that are building data centers. They need electricity and they understand that Deep Vision has an advantage when it comes to time to market. So our ability to meet that demand and do it quickly, we're talking about 2028, 2029 time frame is much more attractive than having to wait into the2030s, at which point, you know, the demand, the demand is there now and the need to build is, is now what

[Interviewer Tim Stanvik]

kind of public response have you had to the idea. What are people saying about the idea of a nuclear power plant buried in their, in their neighborhood?

[Liz Mueller]

Yeah, I think initially people are a little bit surprised. This is very different from all of the other advanced reactor companies that are out there. And so the first response is, well, why are you doing it a mile underground? But the more we expand on the technology, the more we explain that this is proven technology that we are just deploying differently, I think people start to get really excited about our ability to get this done and to get it done quickly.

[Interviewer Tim Stanvik]

Liz, before we let you go, I'm curious if we could zoom out a little bit. When you think about the future of energy in the United States, let's say five, ten years from now, what percent of the total country's energy use do you think is coming from nuclear?

[Liz Mueller]

Well, it's about 20% now, and I think that's going to at least hold and potentially increase. What we're seeing right now, which is really remarkable, is that we need all the electricity that we can get. And so while a few years ago people were talking more about energy transition and there are clean energy benefits from transitioning from, from dirtier types of electricity to nuclear, but what we have right now is we just need to build, we need to make sure that we remain the leaders when it comes to not just AI, but also the production of energy and nuclear can help us get there.

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