Building A Nuclear Plant That Can’t Melt Down
FYI - For Your Innovation
October 1, 2026
In this episode of FYI, Daniel Maguire and Tasha Keeney speak with J. Clay Sell, CEO of X-energy, about the company’s approach to reinventing nuclear power with advanced small modular reactors.
Speakers Clay Sell, Tasha Keeney, Daniel Maguire
TopicsInvestingBusinessTechnology
Clay Sell (0:00)
I'm a firm believer that the facts always ultimately win. Nuclear power is the safest form of generation that has ever been deployed at scale around the world. Let's call it the way it is. We're getting killed by a charm. We're gonna do what the US economy does best, which is innovation. What if we can bring to market a plant that is impossible to melt down?
Tasha Keeney (0:32)
Welcome to FYI, The For Your Innovation Podcast.
This show offers an intellectual discussion on technologically-enabled disruption because investing in innovation starts with understanding it. To learn more, visit arkinvest.com.
SPEAKER_3 (0:50)
ARK Invest is a registered investment advisor focused on investing in disruptive innovation. This podcast is for informational purposes only and should not be relied upon as a basis for investment decisions. It does not constitute either explicitly or implicitly any provision of services or products by ARK. All statements made regarding companies or securities are strictly beliefs and points of view held by ARK or podcast guests and are not endorsements or recommendations by ARK to buy, sell or hold any security.
Clients of ARK Investment Management may maintain positions in the securities discussed in this podcast.
Daniel Maguire (1:24)
So today on our podcast, we have Clay Sell, the chief executive officer of X Energy, a nuclear company developing high temperature gas, cool, advanced, small modular reactors. In April of this year, X Energy raised just over $1.1 billion in the largest nuclear IPO on record. The company has amassed a massive pipeline of over 144 reactors across both the United States and the UK, including an agreement with Amazon to deploy five gigawatts of nuclear capacity by 2039
Previously, Clay served in various US government positions for 14 years, most notably as the deputy secretary of energy under President George W. Bush. We had a great discussion with Clay touching on many topics, including the regulatory environment for nuclear, how X Energy's advanced nuclear design will help the US get back onto its previous cost-declined trajectory that we have spoken about at length at ARK thanks to Wright's Law and also the convergence across energy, AI, and the role that nuclear can play in the national security race against China. So with that, we will leave you to enjoy our conversation with Clay Sell.
Clay, thanks for joining us today on ARK's FYI podcast. It's great to have you here.
Clay Sell (2:40)
Danny, it's great to see you again, and what a pleasure for me to be on your podcast.
Daniel Maguire (2:45)
So it would be great maybe for at the start for those viewers who have never heard of X-Energy, just to give a brief overview of the company's story, and then also your background too and how you became involved in X-Energy.
Clay Sell (2:58)
X-Energy is a company dedicated to completely reinventing the way nuclear power is deployed into the economy.
My particular background is a mix of both government and private sector. I was in the government early in my career and became Deputy Secretary at a relatively young age, at 37 That's the number two person at the Department of Energy. That was 20 years ago. So you now know how old I am now.
And then when I left government in 2008, I went into business. Well, first in the oil and gas and renewable sector. And then about eight years ago, I decided to join up with the founder of X-Energy, Cam Gaffarian, because we held two things very much in common.
We both happen to love this technology, which I want to tell you about. The technical term in our sector is it's called a pebble bed, a high-temperature gas-cold reactor, but I can explain it in layman's terms more effectively. So Cam and I both believed in this technology, and we both believed that a massive bow wave of power demand was going to hit the sector that would absolute require the need for baseload, carbon-free, affordable, super safe nuclear power. Like we believe those two things, and I think now those beliefs are quite in vogue, as evidenced by the 100 SMR companies that have been created in the last few years. But when Cam created the company in 2009, and even when I joined him seven years later, those views were still contrary to the conventional wisdom. But that's my background and that's how we got hooked up.
Daniel Maguire (4:59)
And you kind of touched on the technology, and I think that would be a great place to start for the viewers. So when people think of nuclear, a lot of people think about the large reactors that have water as coolant. But your approach differs with helium, and it's a lot smaller, and you touched on being a small modular reactor. Could you maybe just elaborate on the technology and what are the benefits to Xenergi's approach versus maybe others in the industry?
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