Underground Nuclear Reactors? Inside Deep Fission’s Energy Solution

Liz Muller is the CEO and Co-founder of Deep Fission, a company pioneering a new approach to the traditional light-water nuclear reactor. Rather than using concrete and constructed containment, Deep Fission places the reactor one mile underground, fundamentally changing the design paradigm.

Liz was on the show over five years ago when she was building a company focused on storing nuclear waste deep underground—a related concept. Now, she’s back with a fresh vision and a new venture. Deep Fission recently raised a pre-seed round led by Eight VC, and we wanted to catch up with her to hear how the idea came together and how she’s approaching the challenge this time around.

In this episode, we cover: 

• [1:37] Liz’s previous venture: Deep Isolation and lessons learned
• [4:19] The origin story of Deep Fission and the core insight that sparked it
• [9:37] Cost comparison between underground and traditional above-ground nuclear reactors
• [12:17] Deep Fission’s modular, scalable reactor design
• [19:10] Plans for maintenance, refueling, and long-term waste disposal
• [22:25] Regulatory engagement with the NRC and path to licensing
• [23:24] Initial commercial partnership with Endeavor Data Centers
• [25:07] Advantages of Deep Fission’s approach vs. traditional nuclear plants
• [28:23] Funding milestones and capital raised to date
• [29:10] Liz’s vision for the future of nuclear energy
• [35:03] Who Deep Fission wants to hear from—and how you can help

Episode recorded on March 27, 2025 (Published on April 10, 2025)

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*Editing and post-production work for this episode was provided by The Podcast Consultant