Nuclear energy company placing small modular reactors a mile underground. $FISN
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It's an exciting time for @DeepFission. ⚛️
What if the biggest barrier to expanding #nuclear energy isn't the reactor, but the way we deploy it?
In this overview video, our CEO and co-founder Liz Muller shares about our deployment-first approach and progress toward commercialization, leveraging proven technology in a new way to help meet urgent demand for reliable, affordable power.
Watch ⬇️
“I came back to Parsons to work in our family business, because I believe in this community. When Deep Fission invited me to join the Community Advisory Group, I saw a chance to help make sure the young people who want to build their lives here have real opportunities to do it,” said Zach McCarty, pictured left during our August project site tour.
Zach works in his family’s business, McCarty’s Office Machines in Parsons, and is a member of our Community Advisory Group (CAG).
“Whether you’re thinking about staying or returning home, I want Parsons to be a place where you can build a career and a future. I’m glad to have a seat at the table.”
Other CAG members share his focus on young people. When we asked members during that site visit for project ideas for our future community giving, youth and kids programs topped the list, suggested by 66% of respondents.
Thank you to Zach for keeping the next generation of Parsons part of the conversation, and to all of our CAG members for their time and perspective.
Visit the link in the comments to learn more.
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Learn more —> deepfission.com/sites/parson…
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How do you monitor a reactor a mile underground? Part of the answer is in its water chemistry.
Our Gravity™ Nuclear Reactor is designed with a primary coolant control system that manages the coolant’s volume, pressure, temperature and water chemistry from the surface.
• The coolant is designed to be sampled and analyzed periodically through small-diameter lines that extend from the surface to the reactor depth.
• Sampling is designed to confirm that boron concentration, pH and corrosion product levels remain within specified limits.
• Operators can adjust reactivity by changing the boron concentration.
• Sampling is also designed to detect changes that could indicate fuel cladding degradation or system corrosion.
Coolant sampling is one of several ways the reactor is designed to be monitored. This is the first in a series walking through our DOE-approved Nuclear Safety Design Agreement, the safety framework behind our reactor.
Find the NSDA in the comments. Thanks for following $FISN.
#NuclearEnergy #AdvancedNuclear #NuclearSafety
Same safety standards. Less duplicated paperwork. Here’s what the NRC’s new rule means for advanced nuclear beginning November 25th.
Many new reactors are first tested under the Department of Energy (DOE), then need a separate license from the Nuclear Regulatory Commission (NRC) to sell power. A new NRC rule lets the agency build on DOE’s work instead of starting over. Safety standards stay the same.
Why it matters for Deep Fission:
✅ Our pilot isn’t a test model. It’s the same reactor we plan to use commercially.
✅ In August, DOE approved a key safety agreement for our Gravity™ Nuclear Reactor pilot.
✅ That means the work we’re doing today carries forward to commercial power.
More on our regulatory approach in the comments. 👇
Thanks for following $FISN #NuclearEnergy #AdvancedNuclear #CleanEnergy
“My dad worked in utilities when I was a little girl, so I grew up understanding what it takes to keep the lights on for a community, and the pride that comes with doing that work," said Paula Wyble, pictured second from left alongside Deep Fission staff at our Chickin N Pickin event in August.
Paula is the owner of Edwards Manor in Parsons, KS, and a member of our Community Advisory Group.
"I’ve gotten to know the professionals on the Deep Fission team, and they’re thoughtful, down-to-earth people who take the time to listen and answer questions. As someone who has built a business here in Parsons, I’m excited about what this project could mean for our town and the families who call it home."
Thank you to Paula and all of our CAG members for their time and candor, and for helping us listen to and learn from the Parsons community.
Visit the link in the comments to learn more. Thanks for following $FISN.
A mile underground, gravity can pressurize a nuclear reactor.
Our Gravity™ Nuclear Reactor is designed to sit in a large-diameter, water-filled borehole, cased and cemented from the surface to its full depth. Down there, that mile-long water column creates about 160 atmospheres of pressure, the same pressure the reactor is designed to operate at. Equalizing pressure inside and outside the reactor is intended to enhance the safety of proven pressurized water reactor technology.
Gravity helps with cooling, too. Hot water rises and cooler water sinks, so the water that cools the reactor core is designed to circulate naturally, without pumps, while the surrounding borehole water is expected to keep cooling continuously available. Together, the pressure balance and passive cooling are intended to remove large-break loss of coolant as a credible accident scenario. It’s passive safety by design.
And the mile of rock and water overhead is intended to provide shielding and separation from the surface.
Read more about why we go a mile deep in our FAQ, linked in the comments. Thanks for following $FISN.
Learn more —> deepfission.com/faq
What does a power plant ask of the community around it?
Our Gravity™ Nuclear Reactor is designed to ask for less.
The reactor uses water inside a closed-loop system. At our Parsons pilot, that loop will hold roughly 350,000 gallons, about half the volume of an Olympic-size swimming pool.
The mile-deep column of water in the borehole is designed to provide emergency core cooling without pumps or offsite water sources.
Most U.S. steam power plants use water to cool and condense steam, traditionally drawn from a nearby river or lake. Our design calls for air-cooled condensers instead, which use air to turn steam from the turbine back into water.
Local air quality is part of the picture, too. Nuclear reactors don’t burn fuel, so there’s no combustion-related air pollution. A U.N. Economic Commission for Europe study of 22 electricity technologies also found nuclear had the lowest carbon emissions over its full life cycle.
Read more about how we’re protecting local resources in Parsons in the comments. Thanks for following $FISN.
Read more —> deepfission.com/faq
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View our presentation —>
deepfission.com/investors
Read the article —> breakthroughjournal.org/p/wh…
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Nuclear power hasn’t had a technology problem. It’s had a cost and scale problem.
That’s the problem Deep Fission was built to solve, and it’s why @GoldmanSachs named our Co-Founder and CEO Liz Muller one of the Most Exceptional Entrepreneurs of 2026 at its Builders and Innovators Summit.
“This recognition reflects the ingenuity of our team and our shared conviction that nuclear power can be delivered more affordably and at greater scale,” said Liz.
Goldman Sachs Chairman and CEO David Solomon added that Deep Fission’s leaders “are not simply building a great enterprise; they are redefining what is possible in their industry.”
Congratulations, Liz, and thank you to Goldman Sachs for the recognition.
Full release in the comments. Thanks for following $FISN.
Deep Fission has signed a binding 25-year Master Energy Purchase Agreement with the Great Plains Development Authority in Parsons, Kansas, converting our December 2025 letter of intent into a definitive contract for a planned commercial project at the site of our U.S. Department of Energy pilot.
The initial phase is anticipated to be 150 MW, with a target commercial operation date of September 30, 2028. Later phases could grow the project to a total of 2,000 MW, pending further demand growth.
With Deep Fission’s Gravity™ Nuclear Reactor, we aim to provide reliable, carbon-free, 24/7 power.
Read the full release in the comments. Thanks for following $FISN.
#AdvancedNuclear #NuclearEnergy #CleanEnergy
Read the full release —> deepfission.com/newsroom/pre…
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What comes up tells us what's below.
Before anything nuclear goes in the ground, we characterize the site. A key part of our safety case is the rock itself: keeping the reactor isolated from the surface and behaving predictably over the life of the plant.
In Parsons, Kansas, that work started with our first data acquisition well (G1), drilled to about 6,000 feet earlier this year.
Through geophysical logs, formation pressure testing and fluid sampling, we're learning:
• What the rock is made of and how it's structured
• Where groundwater sits relative to the reactor
• What temperature conditions look like at depth
Above ground, site-specific soil and seismic work completes the picture.
Every hole we drill teaches us something about drilling the next one, and that data feeds directly back into the reactor's design and safety case.
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Can you drill a well wide and deep enough to hold a nuclear reactor?
The answer goes back more than 60 years.
Swipe through the timeline, from the surge in large-diameter drilling in the 1960s, to the injection wells still being drilled today. Our Gravity™ Nuclear Reactor’s deployment plan builds on that record. Our commercial well plan calls for 64-inch casing to 600 feet, 54-inch to 2,300 feet and 44-inch to 6,000 feet, squarely within what the industry has already done.
We are not this hole’s first customer. We are its next one. Read the full white paper in the comments.
Thanks for following $FISN
The White House's National Security Science and Technology Strategy, released in August, calls for "improving energy resilience by establishing microgrids powered by advanced nuclear reactors."
Microgrids keep critical sites running independently of the broader grid. Deep Fission's Gravity™ Nuclear Reactor is designed for exactly this kind of distributed deployment: firm power from a mile underground, sited individually or clustered by the dozens to match a site's demand.
It's also designed to run on standard low-enriched uranium (LEU), the same fuel used in commercial reactors today, and to draw on drilling and manufacturing capabilities that have operated commercially for decades.
As policy prioritizes resilient, distributed power, we're building a deployment model to match.
Thanks for following $FISN
“We are excited to find ways for our students at USD 503 Parsons District Schools to learn more about the work Deep Fission is doing in the nuclear industry," shared Assistant Superintendent Jeff Pegues, a member of Deep Fission's Community Advisory Group.
"I’ve really enjoyed getting to know the Deep Fission team and the professionals working to bring this project to commercialization. I have been thoroughly impressed by everyone I’ve met with the organization—their knowledge, professionalism, and passion for their work are evident. I also appreciate the time and effort they have made to connect with our community and create meaningful opportunities for our students to learn more about the work they are doing.”
Our CAG helps provide a consistent forum for two-way communication between Deep Fission and local community representatives, focused on sharing information, listening to community perspectives, and building mutual understanding.
The group’s objective is to support informed, respectful dialogue on project progress, safety, environmental stewardship, construction activities, and operations.
Visit the link in comments to learn more.
Thanks for following $FISN
Learn more —> deepfission.com/sites/parson…
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