JET

Intelligence Summary: Joint European Torus (JET)

Node Identity: The Joint European Torus (JET), operated by UKAEA at the Culham Centre for Fusion Energy from 1983 to 2023, was the world's most successful fusion facility and the only operational tokamak capable of handling tritium fuel. JET set the world fusion energy record of 69.26 megajoules in its final deuterium-tritium campaign (DTE3) in October 2023, using only 0.21 milligrams of fuel over ~6 seconds with average fusion power of 12.4 MW. Over its 40-year operational life, JET conducted 105,842 plasma pulses and three full-scale DT campaigns (DTE1 1997, DTE2 2021, DTE3 2023).

Strategic Relevance to FRC/Plasma Weapons Context: JET's strategic significance is threefold. First, it is the only facility outside of weapons laboratories that has demonstrated sustained D-T fusion at high power — the 69 MJ record released 20 times the energy of a recent NIF shot, validating that controlled fusion at power-plant-relevant scales is achievable. Second, JET's unique tritium handling capability means the UK has accumulated irreplaceable operational experience in D-T fusion that few other nations possess — expertise directly relevant to both fusion energy and thermonuclear weapons physics. Third, JET's plasma confinement data validates scenarios for ITER and STEP, and its findings on MHD stability, confinement scaling, and alpha particle physics are directly transferable to compact toroidal confinement concepts including FRC/CFR designs.

Technical Focus / Capabilities: JET was a large-aspect-ratio tokamak (major radius ~3m) capable of plasma currents up to 4 MA with additional heating of 25+ MW. Its DTE3 campaign achieved 69.26 MJ from a single discharge and 12.4 MW average fusion power over 5 seconds, with fusion power generation efficiency of 0.36. The DTE2 campaign (2021) previously set a record of 59 MJ. JET's three DT campaigns provided critical data on alpha particle confinement, tritium retention in plasma-facing components, and D-T fusion scaling laws. The UK government secured a record £2.6 billion investment in fusion in 2025/26, building on JET's legacy.

Network Linkage: JET maintains 6 documented connections: validates ITER (provides physics basis and scaling data); validates STEP (UK's next-gen spherical tokamak program); located at Culham/CCFE (physical host facility); operated by UKAEA (institutional operator). JET's decommissioning in December 2023 marks a transition point — UK fusion efforts now pivot to MAST-U (operational) and STEP (in development). JET's European partner network (EUROfusion) ensures its data legacy continues to inform the global fusion enterprise, including ICF weapons programs at NIF, LMJ, and AWE Orion that study related plasma physics regimes.