Axisymmetric toroidal magnetic confinement using external coils and plasma current.
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Magnetic Confinement Fusion • Detailed Family
Tokamak Fusion
Tokamaks use an axisymmetric toroidal magnetic configuration, combining external field coils with substantial plasma current. They have the deepest experimental database among magnetic-confinement systems, while disruption control, exhaust, component life, fuel-cycle closure, maintainability, and whole-plant efficiency remain unresolved power-plant challenges.
Toroidal Magnetic ConfinementLarge Experimental BaseResearch & DemonstrationNo Commercial-Readiness Claim
ADS 43.9 • Phase 4B • Rev 1.0Phase 4B • Concise Comparison
Engineering comparison
Most near-term plant studies assume deuterium-tritium fuel and a neutron-intensive blanket environment.
Major experiments and an international burning-plasma demonstration program; no commercial fusion-electricity plant.
Plasma-science experiments, burning-plasma demonstrations, pilot-plant studies, and possible future electricity or industrial heat.
Disruptions, exhaust and plasma-facing heat loads, magnets and cryogenics, neutron damage, tritium systems, remote maintenance, availability, and recirculating power.
Phase 4 • Technical Education + Terminology + Accuracy
Learn the System
This learning layer explains the system in public engineering language. Definitions are intentionally conceptual: they teach terminology and relationships without providing operating procedures, design set-points, construction dimensions, or protected implementation details.
Maturity checkpoint: Established experimental fusion platform; no tokamak currently supplies commercial electricity.
System walkthrough
How it works — at a safe public level
- Toroidal-field coils create the dominant magnetic field around a doughnut-shaped vacuum vessel.
- A central solenoid and poloidal-field coils induce and shape plasma current.
- External heating systems raise plasma temperature while feedback control maintains position and shape.
- The divertor exhausts heat, helium ash, and impurities from the plasma edge.
- Future power plants must integrate blankets, tritium systems, heat extraction, remote maintenance, and electricity generation.
Key distinction: A tokamak is a plasma-confinement device, not by itself a complete power plant. The most difficult remaining tasks include sustained high-performance plasma, materials lifetime, tritium fuel cycle, maintenance, and integrated plant availability.
Technical vocabulary
Terms worth knowing
Tokamak
A toroidal magnetic-confinement configuration that uses external magnets plus a large plasma current to shape and confine the plasma.
Toroidal field
Magnetic field directed around the long way of a torus, produced by toroidal-field coils in tokamaks and related devices.
Poloidal field
Magnetic field directed around the short way of the plasma cross-section, contributing to plasma shaping and equilibrium.
Central solenoid
A transformer-like magnet used in many tokamaks to induce plasma current and assist plasma startup and control.
Plasma current
Electric current flowing through a plasma. In tokamaks it helps create the poloidal field and contributes to equilibrium and heating.
Divertor
A plasma-facing system in many magnetic-confinement devices that exhausts heat, helium ash, and impurities from the edge of the plasma.
Bootstrap current
A self-generated plasma current arising from pressure gradients and particle orbits in toroidal confinement systems.
Disruption
A rapid loss of tokamak plasma confinement and current. Avoiding and mitigating disruptions is a major engineering and control challenge.
Neutral beam injection
A plasma-heating and current-drive technique that injects high-energy neutral atoms which become ionized inside the plasma.
Radio-frequency heating
Use of electromagnetic waves at selected frequencies to transfer energy to plasma particles and, in some systems, help drive plasma current.
Fusion gain Q
A ratio comparing fusion power produced to external heating power delivered to the plasma or target. Definitions must state the system boundary.
Burning plasma
A plasma in which fusion-produced alpha particles provide a substantial fraction of the heating needed to maintain fusion conditions.
Phase 2 • System Interface Review
System Elements & Interfaces
The primary rendering above provides the visual system context. The callouts below identify major subsystem roles and interfaces without duplicating the hero image or implying a buildable plant layout.
- Toroidal-field magnet system
- Central solenoid and poloidal-field coils
- Vacuum vessel and plasma-facing components
- Heating, current-drive and diagnostic ports
- Divertor and exhaust region
- Cryogenic, power-supply and remote-maintenance interfaces
Subsystem roles are family-level and intentionally qualitative. Exact geometry, operating parameters, materials, controls, maintenance boundaries, and licensing basis are design-specific.
Applications
Where this family fits
Research facilities
Supports plasma-physics, materials, control, and burning-plasma experiments.
Pilot-plant studies
A reference path for studying integrated blankets, maintenance, fuel cycle, and electricity production.
Future energy systems
Electricity or industrial heat only after integrated plant performance and availability are demonstrated.
Engineering Reality Check
Maturity and claims boundary
What the artwork shows
A generalized public-facing concept intended to communicate architecture and subsystem relationships.
What it does not show
No proprietary geometry, device settings, operating windows, safety calculations, fuel-cycle recipes, procurement specifications, control logic, or construction instructions.
Public boundary: Technology classification and public research context only. Advanced fuels and direct conversion remain clearly labeled frontier research; neither is presented as commercially ready.
10-Phase Reactor Program • Phase 2
Standardized fusion technical specification
Standardized public-safe fields support comparison across every fission and fusion family. Values are intentionally qualitative; licensing data, dimensions, operating windows, calculations, control logic, and build instructions remain offline.
Axisymmetric toroidal magnetic confinement using external fields and plasma current
High-field HTS magnets, optimized plasma shape, stronger exhaust control, and integrated maintenance
REBCO-class magnets; tungsten/divertor materials; reduced-activation structures; breeding blanket candidates; tritium barriers
D-T is the conservative plant reference. Helium is the fusion product, but energetic neutrons activate structures and require shielding, component replacement, tritium control, and waste planning.
Thermal blanket and turbine cycle are the conservative reference; direct conversion is not assumed
Major experimental and burning-plasma programs; no commercial electricity fleet
The plasma chamber may shrink with field strength, but neutron shield, blanket, cryostat, divertor, power supplies, hot cells, and turbine systems remain substantial.
Specification boundary: Family-level technology classification and lifecycle context—not a vendor datasheet, safety analysis, procurement specification, or construction package.
Ten-Phase Reactor Program · Phase 5
Safety, licensing, lifecycle & public trust
Phase 5 treats safety as a full lifecycle obligation: site and license basis, fuel/material supply, operation, environmental controls, safeguards, emergency preparedness, waste, decommissioning, and disciplined public claims.
Magnet stored energy and quench, plasma disruptions, heat exhaust, vacuum, cryogens, tritium confinement, activated components and dust, coolant boundaries, remote maintenance, and occupational dose are key safety topics.
U.S. fusion regulation is evolving under the byproduct-material framework. The NRC published a proposed fusion-machine rule in February 2026 and draft possession-license guidance; exact jurisdiction may involve the NRC or an Agreement State depending on location and material authority. A research milestone is not a commercial operating license.
Evaluate site electricity demand, heat rejection, tritium or other radioactive inventories, activated components, coolant and chemical systems, cryogens, magnets, pulsed-power systems, construction, waste storage, and decommissioning. Fusion avoids a fission chain reaction but is not automatically impact-free.
Fuel-cycle obligations depend on the fusion reaction and facility. D-T concepts require tritium inventory control, processing, confinement, accountability, and potentially breeding-system integration. Other fuel concepts have different materials and performance constraints.
Fusion does not create spent fission fuel from the plasma, but neutron-producing concepts can activate structural materials and generate radioactive components, tritium-bearing waste, contaminated maintenance equipment, and decommissioning waste. Waste classification and disposal remain design- and jurisdiction-specific.
Apply graded material control and accounting, physical protection, cybersecurity, transport controls, insider-risk controls, and international safeguards as applicable to the material, facility, mission, and jurisdiction. Public pages must not reproduce Safeguards Information, sensitive security layouts, response tactics, or adversary-useful detail.
Emergency planning should be based on actual radioactive inventories, credible energy releases, chemical and cryogenic hazards, activated material, and site conditions under the applicable materials/facility framework. Lower source terms cannot be translated into 'no emergency plan' without analysis and regulatory acceptance.
State the maturity actually achieved, name the applicable authority, separate family-level evidence from project approval, and distinguish demonstrated performance from projections or marketing.
May describe achieved plasma, target, magnet, driver, materials, or subsystem milestones and the emerging U.S. materials-based regulatory framework. Keep physics gain, target gain, engineering gain, net electricity, plant availability, and commercial licensing as separate claims.
Do not claim radiation-free, waste-free, self-sustaining, commercially licensed, net-electric, maintenance-free, or 'just a small sun.' A Q or ignition milestone does not prove a power plant, grid export, economic competitiveness, or licensing readiness.
Phase 5 evidence:NRC — Fusion ↗NRC — Fusion Machine Rulemaking Status ↗NRC — Draft Fusion Possession-License Guidance ↗DOE — Fusion Energy ↗
Public classification only: This is not a safety finding, licensing opinion, environmental permit, emergency plan, security plan, safeguards determination, waste-acceptance decision, or legal advice. Exact obligations belong to the applicable regulator and project authority.
Phase 7 • Release Certification & Production Integration
Release certification
This page has passed the Reactor Programs Phase 7 branch-level release review for internal routing, asset references, canonical metadata, maturity and terminology controls, source-authority links, accessibility essentials, responsive markup, and release traceability.
Production boundary: this certification covers the Reactor Programs branch package. Parent-site shared CSS, navigation, search, logo, and global assets remain controlled by the Aurora website root and must already exist in production. Live deployment is not implied until the package is uploaded and the production URLs are rechecked.