United Kingdom · Magnetic confinement (spherical tokamak)
Mega Amp Spherical Tokamak Upgrade
Operated by UKAEA · Culham · First operation 2020
Status: Operational
A spherical tokamak testing the Super-X divertor concept — critical for managing exhaust heat in compact fusion power plants.
MAST-U upgrades the original MAST device with the world's first Super-X divertor — a magnetic configuration that spreads heat exhaust over a larger area, potentially solving one of the hardest problems for compact tokamaks like SPARC and STEP.
Key specifications
- Major radius
- 0.85 m
- Aspect ratio
- ~1.4 (low)
- Plasma current
- 2 MA
Milestones
2020
First plasma post-upgrade
2022
Super-X divertor validated — 10× reduction in target heat flux