DTT – the Divertor Tokamak Test facility – is a compact superconducting fusion device designed to explore how best to handle the extreme heat loads expected in ITER and future demonstration fusion power plants. With EUROfusion’s support, DTT has recently completed testing key power supply components and finished winding the first toroidal field coil, paving the way for full operations by the end of this decade.
The DTT facility is a breakeven-class, superconducting tokamak with a toroidal magnetic field of up to 5.85 T and a plasma current of 5.5 MA. Thanks to its compact dimensions (major radius 2.2 m, minor radius 0.7 m) and up to 45 MW of combined heating power (in its final configuration), DTT aims to replicate and study the challenging power exhaust conditions foreseen in ITER and in the European DEMO. Its in-vessel components, made of tungsten, will be actively cooled to sustain long plasma pulses of up to 100 seconds.
Main aim
In line with EUROfusion’s roadmap to fusion electricity, DTT’s principal mission is to address the urgent problem of heat exhaust and the need for a robust solution that balances high-power loads in the plasma core and divertor regions. By operating in conditions representative of future devices and by leveraging expertise from EUROfusion partners across Europe, DTT will test advanced divertor concepts and magnetic configurations such as conventional, X-divertors, and negative triangularity plasmas.
Recent highlights
- First Toroidal Field Coil Winding Pack Completed: ASG Superconductors, under contract for supplying 18 DTT Toroidal Field Coils, has finished the first winding pack (WP-01). This milestone confirms that critical manufacturing steps and quality tests are proceeding on schedule. The remaining 17 winding packs will follow at a rate of roughly one every 1.5 months, with final completion expected by mid-2027.
- Power Supplies for In-Vessel Coils Successfully Tested: The first components of the power supplies for 27 Non-Axisymmetric (NAS) in-vessel coils have passed factory acceptance tests. Each coil, designed to correct error fields and suppress Edge Localized Modes (ELMs), will be independently powered by tailor-made inverters. The power supply system is on track to be delivered to the DTT site by October 2025.
Future plans
DTT’s construction phase is well underway, with close to one third of the budget committed to industrial contracts. Supported by EUROfusion’s investment in the first divertor and continued collaboration among European institutes, plasma operations are slated to begin by the end of 2030. These initial experimental campaigns will provide critical data for ITER and EU-DEMO, focusing on a “core-edge integration” approach – acknowledging that divertor physics, core plasma performance, and external heating and control systems must be studied together.
Beyond its initial mission, the DTT Research Plan (involving around 100 scientists from 20 institutes and 10 different European countries) lays out both near-term and long-term objectives. This plan will be periodically updated during the device’s construction and operation, ensuring that DTT’s scientific programme remains aligned with the needs of ITER, EU-DEMO, and the global fusion community.
By bringing a new dimension of advanced divertor and power exhaust testing to Europe’s fusion research capabilities, DTT is ready to make major contributions to ITER and DEMO – a vital step toward the shared goal of demonstrating fusion as a viable, clean, and sustainable energy source.