Where smokestacks once fed power to millions, an American start-up now wants to build a fusion reactor – and regulators are being asked to treat it like a real power station, not a science project.
From coal to fusion on the Clinch River
The Bull Run Fossil Plant, a 865 MW coal-fired station near Oak Ridge, Tennessee, shut down at the end of 2023 after more than fifty years of operation.
The site comes with heavy industrial infrastructure, a grid connection and a workforce steeped in energy know‑how.
Type One Energy, a US fusion start-up, plans to reuse this exact footprint for a fusion power project called “Infinity”.
Where coal once burned, Type One Energy wants a reactor that produces electricity without combustion, carbon or chain reactions.
The company has just submitted a formal licence application for handling “byproduct materials” linked to its fusion activities, working with the Tennessee Department of Environment & Conservation and the Tennessee Valley Authority (TVA).
No US fusion company had gone this far into the conventional nuclear regulatory process before.
Infinity: a two-stage path to grid power
Infinity One: prototype and training hub
Infinity is designed in two major stages on the Bull Run site.
- Infinity One: a prototype fusion machine and training centre, operated directly by Type One Energy, with first operations targeted for 2029.
- Infinity Two: a 350 MW electric fusion plant intended to run as a baseload power station on the grid.
Infinity One aims to prove that the chosen technology works in a near‑industrial setting while building up a pool of trained operators, engineers and regulators familiar with day-to-day fusion operations.
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Infinity Two, the follow‑up plant, is designed from the start as a commercial-scale generator, with output comparable to mid‑size gas or nuclear fission units.
TVA, the federally owned power authority that dominates electricity generation in the region, has signed a letter of intent expressing interest in developing and building Infinity Two, subject to regulatory and financial approvals.
By linking a prototype and a 350 MW plant on the same site, Type One Energy wants to compress the usual decades-long fusion timeline into a single development arc.
A different flavour of fusion: the stellarator
Why Type One Energy is backing twisted magnets
Most of the headlines around fusion focus on tokamaks, like the ITER project in southern France, which confine plasma in a smooth, doughnut‑shaped magnetic field.
Type One Energy is betting on a different architecture known as a stellarator.
Instead of a symmetrical ring, a stellarator uses a twisted, almost figure‑eight geometry of magnetic coils that shape and hold the super‑hot plasma.
The key idea is stability.
Tokamaks rely on large electrical currents flowing through the plasma itself, which can make them prone to sudden instabilities and shutdowns.
Stellarators create the confining magnetic field mostly with external coils, reducing the need for strong internal plasma currents.
Modern computing and advanced manufacturing allow far more precise coil designs than the clumsy stellarators of the 1980s, which struggled to compete with tokamaks.
The Bull Run project treats the stellarator not as a physics toy, but as the backbone of a 350 MW power station that must run day in, day out.
Fusion steps into regulatory law
A licence that changes the conversation
For decades, fusion experiments sat in national laboratories, shielded from commercial rules and electricity markets.
Type One Energy’s licence application marks a shift: fusion is being nudged into the same legal channels as fission plants and other nuclear facilities.
The application concerns so‑called byproduct materials, a category usually associated with radioactive substances handled in medicine, industry or research.
By working with state environmental regulators and TVA, the company is trying to show that fusion can be governed under existing frameworks rather than waiting for brand‑new legislation.
The goal is to anchor fusion in “normal” industrial law, with safety rules written into the design instead of bolted on at the end.
A plant designed to be licensable anywhere
Infinity Two is being engineered as a product that regulators around the world could, at least on paper, license without tearing up their rulebooks.
That means wide safety margins, clear accident scenarios and transparency about every stage of operation, from fuel handling to waste streams and decommissioning.
Type One Energy wants regulators to focus on predictable, well‑bounded risks, not on exotic plasma physics that only a handful of experts understand.
- High intrinsic safety, with no possibility of runaway chain reactions
- Limited and short‑lived radioactive materials compared with fission
- Design choices that prevent large off‑site releases in credible accident cases
- Modular components to simplify maintenance and upgrades
If this approach holds, future sites – in the US or abroad – could reuse the same licensing logic, cutting time and cost for later plants.
Tennessee as a fusion policy testbed
Tennessee has a long nuclear history, centred on Oak Ridge, a major research hub since the 1940s.
State officials now want to extend that legacy from fission to fusion, positioning Tennessee as an early home for commercial fusion projects.
The Bull Run project brings together a nimble start‑up, a large public utility and state regulators willing to work through novel questions.
This triangle creates a useful test case for other US states and foreign governments watching from the sidelines.
By shaping rules while the technology is still maturing, Tennessee hopes to attract investment and set benchmarks others will copy.
North America’s crowded fusion race
Type One Energy is entering a dense field of North American fusion hopefuls, each pursuing a different technical route.
| Company | Country | Main approach | Key idea | Energy goal | Status |
| Commonwealth Fusion Systems | US | Compact tokamak | High‑temperature superconducting magnets | Grid power | SPARC reactor under construction |
| Helion Energy | US | Pulsed fusion | Electromagnetic compression, direct electricity | Power without turbines | Advanced prototype |
| General Fusion | Canada | Compression fusion | Mechanical pistons and magnetised plasma | Grid power | Demo plant in development |
| TAE Technologies | US | Linear magnetic confinement | Beam‑stabilised plasma | Long‑term power | Advanced research |
| Zap Energy | US | Stabilised Z‑pinch | Self‑confined plasma currents | Compact power | Experimental prototype |
| Princeton Stellarators | US | Compact stellarator | Simplified magnetic geometry | Grid power | Concept phase |
| First Light Fusion | US / UK | Inertial fusion | Hyper‑fast impact on a target | Long‑term power | Physical demonstrations |
| Lockheed Martin | US | Compact fusion | Proprietary magnetic design | Mobile energy | Confidential programme |
Many of these firms grew out of MIT, Stanford or national labs, and tap into deep pools of private capital and federal infrastructure.
The regulatory move in Tennessee sends a signal to all of them: the game is no longer only about physics milestones, but also about who can build a plant that real regulators and grid operators accept.
What fusion could mean for grids and climate
If projects like Infinity Two work, they slot neatly into existing power systems.
A 350 MW fusion plant can run steadily, supporting variable wind and solar without depending on gas peaker plants.
Fusion fuel – typically isotopes of hydrogen – carries no CO₂ emissions at the point of use and needs only tiny volumes compared with coal or gas.
There are still radioactive materials, largely from neutron activation of structural components, but the quantities and lifetimes are far lower than spent fuel from fission reactors.
For coal communities, the Bull Run model offers a tangible scenario: reuse existing grids, cooling systems and some workforce skills, while swapping out boilers and smokestacks for magnets and vacuum chambers.
Key terms and real‑world risks
A few expressions tend to confuse non‑specialists.
- Plasma: a gas so hot that atoms break into charged particles, which can be steered by magnetic fields.
- Confinement: keeping that plasma hot and dense for long enough that fusion reactions outnumber energy losses.
- Q factor: the ratio of energy produced by fusion to the energy put into the plasma; commercial plants need a high Q plus efficient power conversion.
Real risks around early fusion plants are less about fictional “mini suns” and more about mundane industrial issues.
Components face brutal heat loads and neutron damage, raising tough questions over maintenance schedules and replacement costs.
Construction budgets can easily run into the billions, and delays would test investor patience, especially if competing clean technologies keep getting cheaper.
Regulators, meanwhile, must balance caution with flexibility so they do not block safer reactors while leaving ageing fossil assets running for lack of alternatives.
The Tennessee licence push does not mean fusion has arrived, but it shows that the race is shifting from whiteboards and labs to permits and concrete.
