JET Sets World Fusion Energy Record of 22 MJ in DTE1 Campaign

During the DTE1 campaign in 1997, the Joint European Torus (JET) at Culham produced 16.1 megawatts of peak fusion power and 21.7 megajoules of total fusion energy in a single discharge — world records that would stand for more than two decades. The achievement also yielded the highest fusion energy gain (Q ≈ 0.67) ever recorded in a magnetic-confinement device at that time.

JET's ITER-relevant geometry, beryllium-tungsten wall environment, and tritium inventory made the DTE1 results directly applicable to the design of ITER, then in its conceptual phase. The European team demonstrated reliable D-T operation in a device shaped, sized, and conditioned to match the conditions ITER would face two decades later.

The DTE2 campaign in 2021–2023 broke JET's own records, producing 59 megajoules of fusion energy in a single five-second pulse — but the 1997 result remains the foundational data point that justified ITER's construction at Cadarache. JET ceased operations in late 2023 after a 40-year run that remains the longest continuous experimental program in the history of fusion energy research.