Capturing ITER’s engineering journey
Several chapters of the first volume of the ITER Engineering Basis Handbook have been released, marking an important milestone in preserving the engineering memory of the world’s largest international fusion experiment in the advanced stages of construction in Cadarache, in the South of France. Under the editorial lead of EUROfusion and its Programme Manager, Gianfranco Federici, this handbook brings together ITER’s design principles, the underlying technical design basis and its evolution from conception to construction.
Conceived as a stand-alone reference work, the handbook explains not only what ITER looks like today, but also why it was designed this way. It documents the scientific, technical and regulatory rationale behind key choices and highlights the alternatives that were considered and set aside along nearly four decades of planning and construction.
The main purpose is to secure the lessons learned, return of experience and knowledge transfer from the largest fusion project, drawing from the direct experience of knowledgeable experts who have worked on ITER, for the benefit of fusion professionals inside and outside of the ITER project and the next generation.
A compendium for fusion’s next steps
When launching the handbook project in 2023, ITER Director-General Pietro Barabaschi set a clear objective: to capture the full breadth of ITER know-how from engineering and fabrication to assembly, safety and licensing before it risks being lost as experts retire or move on.
Some of the roughly 80 authors who contribute to the handbook were already involved in the Conceptual Design Activities (CDA) and Engineering Design Activities (EDA) in the late 1980s and 1990s. Others joined later in the project, taking on key technical and management roles within the ITER Organization. What they share is first-hand experience at the moments when crucial engineering decisions were taken — experience that is difficult to reconstruct from formal documents alone.
By consolidating information scattered across reports, design descriptions and internal notes, the handbook makes ITER’s technological journey easier to access and understand. It is designed to serve fusion professionals inside and outside the ITER project, as well as the next generation of engineers and scientists who will design, build and operate devices beyond ITER.
EUROfusion at the editorial helm
The handbook is being developed in close partnership between ITER and EUROfusion. An editorial board led by EUROfusion Programme Manager Gianfranco Federici coordinates the structure and content, working with chapter authors, subject-matter experts and senior retired experts from across the ITER community.
The project delivery team brings together:
- An editorial team responsible for the overall narrative and consistency of the two volumes
- A coordination unit linking ITER’s internal knowledge base with the external contributors
- Specific chapter authors and reviewers covering areas from plasma physics to magnets, blanket systems, safety and licensing
What is available today
Volume 1 of the handbook, titled “Genesis, Design and Evolution”, provides the global context and high-level description of ITER. The first chapters now available include:
- Foreword (Chapter 1) – introducing the purpose of the handbook and its role in the broader fusion landscape
- Acknowledgements (Chapter 2) – recognising the many contributors behind ITER’s design
- Introduction (Chapter 3) – outlining the structure of the two volumes and how to navigate them
- The role and distinctive features of ITER (Chapter 4) – explaining how ITER differs from present-day devices and why its parameters were chosen
- ITER key historical events (Chapter 5) – describing the main historical events and major milestones on the road to ITER, from its inception until today.
- Gaps to fill beyond ITER (Chapter 9) – explaining the prospects fusion and common issues and technology challenges remaining with emphasis on the low readiness of some enabling core fusion technologies
Additional chapters of Volume 1, including Ch. 6 – Project genesis & evolution, Ch. 7 – ITER design evolution and technology maturation, and Ch. 8 – Managing the design & construction of ITER will be published soon. Volume 2, “Anatomy of the Plant”, will then describe in more detail the individual systems that make up the ITER facility, with publication of its seven chapters expected by the end of 2026.
The first chapters can be downloaded from the dedicated ITER Engineering Basis Handbook page under ITER Technical Reports on the ITER website.
Access the handbook:
ITER Technical Reports – ITER Engineering Basis Handbook (searchable under Scientists → ITER Technical Reports).
An open invitation to contribute
The handbook is conceived as a living document that will evolve alongside the project. Readers are explicitly invited to share comments and suggestions that can help improve future versions of the chapters and identify gaps or topics that deserve additional attention.
Feedback can be sent directly to the ITER library at library@iter.org.
By opening the editorial process in this way, ITER and EUROfusion aim to ensure that the handbook reflects not only the history of decisions taken so far, but also the needs of the broader fusion community that will use this knowledge.
Securing knowledge for future fusion power plants
ITER is designed to be a bridge between today’s experimental devices and tomorrow’s fusion power plants. Beyond generating megawatts of fusion power, it will generate a large body of practical engineering knowledge—from materials performance to maintenance concepts and licensing approaches—that is highly relevant for devices such as EU-DEMO and future commercial plants.
By documenting this knowledge in a structured and accessible way, the ITER Engineering Basis Handbook supports one of EUROfusion’s core objectives: to enable efficient knowledge transfer from current flagship projects to the next generation of European and international fusion facilities.
