David Kirtley is a nuclear engineer, fusion expert, and CEO of Helion Energy, a company developing nuclear fusion reactors with ambitious timelines that could revolutionize clean energy. Helion has made remarkable progress building seven successive fusion prototypes and securing a 2028 contract with Microsoft to deliver grid-connected fusion power.

The conversation explores the fundamental differences between nuclear fusion and fission, with fusion combining light hydrogen atoms (the same reaction powering stars) while fission splits heavy uranium atoms. Fusion offers inherent safety since reactions simply stop when fuel input ceases, produces no long-lived radioactive waste, and uses abundant fuel from seawater.

Helion uses a unique approach called pulsed magneto-inertial fusion, creating Field Reverse Configuration (FRC) plasmas that self-organize when magnetic fields are rapidly reversed. This differs from traditional tokamaks and stellarators, potentially enabling direct electricity generation at much higher efficiency than steam turbine systems.

Nuclear Fusion vs Fission: The Physics of Energy Creation

Fusion powers the universe by combining lightweight hydrogen isotopes, releasing energy through Einstein's E=mc² when the resulting nucleus weighs slightly less than its components

Fission uses naturally occurring heavy elements like uranium and plutonium that are 'fundamentally unstable' and break apart when struck by neutrons, also releasing energy through mass conversion

Fusion fuel (deuterium) exists in all water on Earth, providing 100 million to 1 billion years of energy at current consumption levels - 'It's everywhere' - David

Fusion requires extreme conditions: 100+ million degree temperatures where particles move at 'million miles per hour' velocities to overcome electromagnetic repulsion between nuclei

Field Reverse Configuration: Self-Organizing Plasma Physics

Helion's approach reverses magnetic fields in under a microsecond, faster than million-degree particles can move, causing plasma to 'self-organize into a closed field'

The plasma becomes its own electromagnet with electrical current flowing inside, generating magnetic fields that trap itself - 'it traps itself' - David

FRC stability requires the parameter S-star over E, like spinning a top fast enough to stay upright, achieved through high particle velocities and elongated geometry

Systems operate at plasma beta equals one, meaning particle pressure equals magnetic pressure, enabling maximum energy extraction efficiency

Direct Electricity Generation: Beyond Steam Turbines

Traditional fusion uses neutrons to heat water for steam turbines at 30-35% efficiency, while Helion's charged particle approach enables 80-95% direct electrical conversion

Deuterium-helium-3 fuel produces only charged particles that push back on magnetic fields, 'recharging the capacitors where we started this whole process'

Helium-3 requires higher temperatures (200-300 million degrees) but eliminates neutron activation and enables the high-efficiency direct conversion pathway

Pulsed operation allows power output adjustment from 1-10 times per second, with demonstrated capability up to 100 Hz for grid load following

Rapid Prototyping: Seven Generations in Record Time

Helion built seven fusion systems from IPA through Polaris, with Trenta achieving 100 million degrees and demonstrating deuterium-helium-3 fusion in 2020

The company prioritizes speed over perfection: 'We spend a lot of time on eBay' to avoid 9-month supply chain delays for vacuum pumps and other components

Manufacturing philosophy emphasizes mass-producible components: 'by making a hundred of a thing, you can actually make it faster than if you go make one of a thing'

Team composition is 50% technicians rather than scientists, with vertical integration including conveyor belt manufacturing for power supplies

Microsoft Partnership and 2028 Timeline

Microsoft contracted Helion to deliver a grid-connected fusion power plant by 2028, creating 'a very, very tough, ambitious timeline' that drives daily decision-making

The power plant will generate electricity for Microsoft data centers, with potential for direct DC power delivery to avoid AC conversion losses

Helion is already building manufacturing infrastructure and conducting environmental/regulatory analysis for the commercial deployment

Data centers represent ideal fusion applications due to high power density needs and compatibility with DC electrical output from fusion reactions

Fusion Safety and Proliferation Resistance

Fusion systems contain only 'one second of fuel' at any time and cannot sustain reactions without continuous fuel input, making meltdowns physically impossible

Nuclear Regulatory Commission analysis showed that even if 'a meteor strikes' a fusion plant, no population evacuation would be required

Fusion cannot be used for weapons production, with proliferation experts telling Helion: 'please, please go develop fusion power plants absolutely as fast as possible'

Hydrogen bombs still require uranium fission primaries, with 90% of energy from fission reactions rather than fusion components