Fusion and advanced nuclear

The companies building fusion devices and advanced reactors.

238 companies, 146 fusion devices and 161 fission reactors. A company page lists its machines and any funding on record. A device page lists what has been measured on it, with the date and the source.

Companies Devices

A tokamak, one way to hold a fusion plasma · Drag to orbit

Gain

National Ignition Facility · shot N221204 · 5 December 2022

The same shot, two gains. They differ by a factor of about 190. The first asks whether the fuel physics worked. The second asks whether the facility as a whole came out ahead. A headline that reports one while implying the other is the most common way fusion results are overstated, so this dataset has no field for a gain without its denominator.

1.5

Target gain (Q_target)

Total fusion energy yield of the implosion ÷ Laser energy delivered to the target, including hohlraum losses

3.1 MJ ÷ 2.05 MJ

Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment independent · Achieving Fusion Ignition | National Ignition Facility & Photon Science operator

achieved
0.0078

Wall-plug gain

Total fusion energy yield ÷ Total facility grid energy drawn for the shot

Power Conditioning System operator · Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment independent

claimed

All 20 gain figures The 6 kinds of gain

Fusion triple product (nTτ_E)

The top 5 of 21 ranked devices, in 10²¹·m⁻³·keV·s. Triple product is the one figure comparable across tokamaks, stellarators and laser fusion. Planned values never enter a ranking.

Fusion triple product (nTτ_E), top 5
#	Device	Operator	Value	Status
1	Tokamak Fusion Test Reactor	Princeton Plasma Physics Laboratory	0.79	claimed1995-02-17
2	Joint European Torus	UK Atomic Energy Authority	0.61	claimed1991-11-02
3	JT-60U	JAEA	0.56	claimed1998
4	DIII-D	General Atomics	0.37	claimed1997
5	Alcator C	MIT Plasma Science and Fusion Center	0.12	claimed1984

All 4 leaderboards

Method

Sourced: Each captured page is stored with its SHA-256 hash, so a page that later changes cannot change what was recorded. Every source is labelled by independence: a peer-reviewed paper or a regulator docket is marked apart from the subject describing itself. Coverage
Denominator stated: There is no field for a bare gain. Gain is held as 6 separate kinds, each with its numerator and denominator written into the metric registry. Gain
Status kept apart: Every figure is marked achieved, claimed or planned. Achieved means measured on a dated shot and checked against its source. Planned targets and design values never appear in a ranking. Benchmark
Rejections published: 12 figures are disputed or superseded, and each is shown with its reason. Corrections are appended to a hash-chained ledger rather than overwritten. Disputed and superseded Changelog

Methodology in full

Uses

Journalists: Check which gain a headline means, and whether a record was measured on a shot or is a target. Gain Check a source
Analysts and investors: 98 funding deals, split by instrument. Grants, milestone awards and offtakes are never added into one "total raised". Investment Companies
Policy staff: 30 licensing milestones, anchored to docket and application numbers, with denials and withdrawals recorded alongside approvals. Licensing Modular reactors
Researchers: Every record with its sources, status and confidence, on its own page. Cite the page and the date you read it; every later change is in the changelog. Devices Changelog

Dataset

9of 149 recorded results and targets are achieved: measured on a dated shot and checked against the source. Most of the rest are claims.Benchmark
584of 733 figures are design values: what a machine was built to do, not what it has done. They never enter a ranking.Devices
59of 1,264 sources are independent of what they describe, such as peer-reviewed papers and regulator dockets.Coverage

What the dataset holds
Record	Count	Where
Companies	238	Companies
Fission	115	Fission companies
Fusion	90	Fusion companies
Supply chain	53	Supply chain companies
Fuel cycle	26	Fuel cycle companies
Fusion devices	146	Fusion Devices
Fission reactors	161	Fission Modular reactors
Figures	733	Benchmark Leaderboards
Licensing milestones	30	Licensing
Funding deals	98	Investment
Countries	72	Countries
Sources	1,264	Coverage Changelog

A company can sit in more than one sector, so the sector rows add up to more than the company count. Counted from the records at build time, 2 October 2026.