ITER Design Handbook

By, Piers Letcher

The contributions that ITER is making to fusion physics and engineering—through decades of decisions and implementation—are delivering insights to the fusion community that likely could never have been learned in any other way. Pioneering activities in design, integration, manufacture, assembly and operation not only drive the ITER Project forward, but help to advance future generations of nuclear fusion devices. At the direction of the ITER Director-General, a new initiative is underway to safeguard ITER’s legacy and prevent the loss of knowledge.

ITER is a huge, truly multi-dimensional project, already spanning decades. The wealth of technical information, the lessons learned, and the evolutionary design narrative of ITER is contained across a multiplicity of platforms and sources—including the multi-generational knowledge and experience detained by those who have been involved in the project.

The new project is being spearheaded by Gianfranco Federici, who was involved in ITER back in the 1990s, and is currently working at EUROfusion. Between now and the end of 2026, Federici is leading the editorial board charged with building a comprehensive compendium to consolidate the information and accrued knowledge in an accessible and understandable manner.

“It’s an exciting, complex and also somewhat daunting project,” says Federici. “Our objective is to deliver a single, stand-alone publication detailing the design methodologies and principles, the underlying technical design basis for ITER, and its evolution from the years of conception to the start of construction. We also want to detail the technical, scientific, and regulatory rationale behind major decisions.”

The project delivery team will comprise an editorial team, a coordination unit, and specific chapter authors, together with subject matter experts from numerous affiliations and senior retired experts. Acting as the bridge between ITER and the editorial board are Akko Maas, Science Coordination Officer in the Office of the Director-General, and Jesús Izquierdo, Deputy Head of the ITER Central Integration Division.

The ITER Document Control group has already started work on compiling existing documentation, and retrieving, scanning and digitizing old paper-based documents going back to the very beginnings of ITER.

“In retrospect, we have to admit that we have done an incomplete job in publishing ITER engineering decisions,” says Izquierdo. “We need to catch up now, to ensure that the vital legacy of ITER isn’t lost when that first generation of ITER engineers and physicists disappears. Part of the problem is that engineers, unlike physicists, tend to focus on projects rather than publishing, and aren’t always 100% documentation focused. So we need to go back and make sure we understand how everything was done, and record that.”

“We’re going to document not just when technical decisions and fundamental technology choices were made, but why they were made,” adds Federici. “A huge amount of research and development was required, and was done, and we need to show the lessons learned—both bad and good.”

As Director-General Barabaschi has pointed out repeatedly, the scholarly tendency is to publish good results, not the lessons learned from avenues that were ultimately abandoned. But both are important: both the “know-how” and the “know-how-not” so to speak.

The collaborative inclusion of senior retired experts alongside next-generation engineers is an essential part and key strength of the project.

“Indeed, it’s one of the most exciting parts of the project, for me,” continues Federici, “We’re going to talk to as many as possible of the senior people who were there back when we designed ITER. This is the very last chance we have to capture their first-hand expertise, as the first generation gets older. And it’s wonderful to see the passion these engineers and physicists still have for ITER, even though some of them are now long-retired.”

The scope of the ITER Design Handbook project is itself ambitious, and it will be a challenge for the team to consolidate everything into a succinct publication that can facilitate accessibility and understanding both for stakeholders involved in ITER today and the wider fusion community. One of the main goals is to make the information available and easily accessible to those who are being asked—or who will be asked—to take informed decisions on ITER’s evolution moving forward.

“Organizing data and information is its own skill,” says Izquierdo. “In the old days, the challenge used to be in simply getting hold of the data in the first place. But the new challenge, with data absolutely omnipresent, is to screen out what’s useful from all the noise surrounding it. We clearly need to move up the value chain from data to information to knowledge, and that’s really our job here, in building the ITER Design Handbook.”

There’s a lot of ground to cover in ensuring a full understanding of the complexities, from the project genesis and the design evolutions, from conception right through to today. It needs to include a full description of the device—and the reasoning behind the many technical choices that were made along the way to ensure that systems meet the established project specifications and requirements in terms of performance and operation. These choices will encompass everything from the magnet design and vacuum systems to the safety and confinement process, and the shape of the plasma itself. All of this must be done in a clear stand-alone manner that doesn’t require privileged access to a document management system.

The goal is full transparency—so that the Design Handbook can serve as a valuable tool for all ITER stakeholders, as well as being a useful reference across the private sector, and a global educational resource for those studying within the nuclear fusion domain.

“I think it’s important also to help bring some realism and engineering sense to both private and public enterprises,” says Federici. “We’ve seen a lot of extremely optimistic statements. The promise of fusion energy is so great that it is easy to over-hype, by neglecting to add the caveats and remaining hurdles. And this is partially our fault. But now we need to share the knowledge we have—so that everyone truly understands the challenges and possible pitfalls.”

“We want this to be a useful and important contribution of the ITER Project,” adds Izquierdo, in closing. “By its very nature, ITER is meant to be a gift to humanity and to society, and we feel that sharing the knowledge we have is an important part of that. After all, knowledge—just as much as megawatts—is power.”

Knowledge and experience have been accumulating since the earliest design and engineering efforts for the ITER Project. (This photo dates from the mid-1990s; notice the early ITER logo.) Capturing and disseminating this legacy will help advance future generations of nuclear fusion devices.