The United Kingdom's national fusion research laboratory, operated by the UK Atomic Energy Authority, home to the record-setting JET tokamak and the pioneering MAST Upgrade spherical tokamak.
The Culham Centre for Fusion Energy (CCFE), located at the Culham Science Centre in Oxfordshire, England, is the UK's national laboratory for fusion energy research. Operated by the United Kingdom Atomic Energy Authority (UKAEA), CCFE has been at the heart of European and global fusion efforts since the 1960s, hosting the world's most powerful tokamak — the Joint European Torus (JET) — and developing the technologies needed to move from experimental devices to commercial power plants.1
JET, operational since 1983, was built as a collective project of the European fusion community and has been the flagship of the European programme for four decades. With a major radius of 2.96 meters and a plasma volume of approximately 100 cubic meters, JET remains the only operational tokamak capable of using tritium fuel, making it an indispensable test bed for ITER-relevant experiments.1
JET's landmark achievements include the first controlled release of deuterium-tritium fusion power in 1991 (producing 1.7 MW), a record 16 MW peak fusion power in 1997, and the 2021-2022 campaigns that demonstrated sustained fusion output with an ITER-like beryllium-tungsten wall. These final D-T experiments provided irreplaceable data on fuel retention, plasma-wall interactions, and isotope effects that will directly inform ITER operations.2
The Mega Amp Spherical Tokamak Upgrade (MAST-U), which achieved first plasma in October 2020, is CCFE's other major experimental facility. A spherical tokamak with a uniquely compact geometry and an aspect ratio near 1.4, MAST-U is designed to explore the physics of spherical tokamak plasmas and to test the innovative Super-X divertor concept — a novel exhaust geometry that spreads the plasma heat load over a much larger area, potentially solving one of fusion's most challenging engineering problems.3
Early MAST-U results have demonstrated a tenfold reduction in target heat flux using the Super-X configuration, a result with far-reaching implications for the design of future fusion power plants.
Beyond its experimental programme, UKAEA Culham leads the Spherical Tokamak for Energy Production (STEP) initiative, the UK government's plan to design and build a prototype fusion power plant. STEP would produce net electricity from fusion, employing a spherical tokamak design informed by decades of MAST and MAST-U research. The programme received initial government funding in 2019 and selected West Burton, Nottinghamshire, as the construction site in 2022.4
CCFE operates extensive facilities for remote handling, materials testing, and tritium processing. Its remote handling expertise, developed for JET maintenance in activated conditions, is recognized as world-leading and informs the design of maintenance systems for ITER and future reactors. The Materials Research Facility at Culham studies the behavior of structural materials under neutron irradiation relevant to fusion conditions.5
Culham's combination of JET's D-T record, MAST-U's divertor innovation, and the STEP power plant programme makes it one of the most comprehensive fusion research sites in the world. As JET completes its scientific mission, CCFE's focus shifts decisively toward the engineering and technology challenges of building an actual fusion power station.