Today’s landscape around nuclear fusion R&D has a unique structure. Since the 1980s, a great deal of attention and resources have been directed to one major, enormous project: ITER, a multinationally backed facility currently under construction in southern France. While ITER will not itself produce usable energy, it is considered important for studying how to ignite and control burning plasmas, which produce more energy than it takes to create and maintain them.

Yet, even as work continues on ITER, the momentum has arguably shifted elsewhere. Within the last decade, dozens of efforts have sprouted up globally to drive more quickly toward a smaller-scale commercial fusion reactor using newer technologies. According to the Fusion Industry Association’s latest survey of the startup landscape, about $10 billion has now been invested in such efforts. One standout privately funded project is the SPARC and follow-on ARC machines being built by Commonwealth Fusion Systems, a spinoff from MIT, which operated the “Alcator” series of experimental fusion devices between 1972 and 2016.

The United Kingdom is also a major player. The Culham Centre for Fusion Research near Oxford was established in 1960 by the UK Atomic Energy Authority (UKAEA) and operated a major, internationally supported facility called the Joint European Torus (JET) from 1983 to 2023. A subsidiary of UKAEA is now developing a prototype fusion plant called STEP. China is likewise making a hard charge in fusion, as it is in many other areas. Currently, it is operating a high-performing experimental reactor called EAST, building a compact experimental reactor called BEST, and planning an energy-generating facility called the China Fusion Energy Test Reactor.

John Adams’s push for work on fusion

While some parts of the fusion landscape are quite new, other aspects can be traced to decisions made as far back as the 1950s. In an open-access article in the British Journal for the History of Science, historian Barbara Hof focuses on an early, unadopted proposal to create a unified European fusion research program at CERN (then still known as the European Organization for Nuclear Research). While something of a footnote in CERN’s history, it is still a significant episode that bears on the flourishing of fusion research in the UK and the proliferation of fusion research labs at universities and national research institutes before the emergence of more integrated efforts like JET and ITER.

Research on controlled fusion originated in the hydrogen bomb development programs of the US, UK, and the Soviet Union. While initially shrouded in secrecy, much of the work was made public as part of the Second United Nations International Conference on the Peaceful Uses of Atomic Energy in 1958. This shift immediately opened the question of how civilian fusion research programs might be structured, including their scale, the intensity of international cooperation, and to what extent they would be basic research programs in plasma physics or applied research programs aimed at actually building a reactor.

And these questions were not only tricky in themselves; they were entangled with preceding and contemporaneous developments in the organization of atomic weapons programs, civilian nuclear energy programs, and international efforts to collaborate on major research projects, not to mention broader currents in international relations.

As Hof relates, the key figure in Europe in attempting to navigate this landscape was British engineer John Adams —who had an absolutely remarkable career, given he had no university education. Starting in industry, he worked in Britain’s radar development program during World War II, and afterward joined the new UKAEA’s nuclear energy research establishment at Harwell. In 1953, he moved to CERN, which was just being set up in Geneva, as part of the division building the lab’s Proton Synchrotron particle accelerator. He became the division’s director in 1954.

By 1958, with completion of the Proton Synchrotron in sight, the question arose of what was next for CERN. It was at that time unclear that the lab would build additional accelerators, and it faced a potential exodus of talent. Adams was still in contact with his colleagues at Harwell, which had been working on a highly publicized fusion device called ZETA. He advocated that CERN become involved in fusion and plasma research, and he gained support from CERN’s director-general, Cornelis Bakker, and the president of the CERN’s governing council, François de Rose.

Supporting fusion at CERN made a certain amount of sense in that there were similarities between the physics and engineering problems involved in accelerating particles and controlling plasmas, and in fact CERN already supported some small-scale plasma research. Moreover, if the UN conference signaled that fusion was an area for international collaboration in atomic energy, then CERN—created explicitly to foster international research—would be a logical place for it.

The push at CERN against fusion

At the same time, as an international institution, making decisions at CERN was a complicated matter of interpersonal and international diplomacy, and Hof documents the significant opposition that arose against fusion. Werner Heisenberg, the German representative on CERN’s Scientific Policy Committee, raised the concern it would require investment in costly new machines. The UK representative, Patrick Blackett, argued that fusion research was inappropriate for an institution that was supposed to work only in basic research. This latter point was answered by Bakker and the committee’s chair, Edoardo Amaldi, who argued it would be possible to work on the subject without venturing into practical applications.

Probably the most serious opposition arose from the UK delegation to the CERN Council, joined by several other countries’ delegations. Here the main issue was that the CERN effort was poised to be done under contract with the European Atomic Energy Community (EURATOM). EURATOM had just been set up in 1957 to fund and coordinate work on nuclear power in Europe, and it did not include the UK, among other CERN member states. And ultimately, the UK’s reluctance to collaborate closely with other European countries on nuclear energy proved an insurmountable barrier to collaborating on fusion via CERN. CERN decisively dropped the idea of continuing work in the area in 1960 as it turned to follow-on work in particle physics.

John Adams’s push to work on fusion at CERN did result in the establishment of a study group aimed primarily at examining the research made available through the 1958 UN conference. The overarching message to be gleaned was that the near-term prospects for controlled nuclear fusion were discouraging, contributing to the dampening of interest in a cross-European laboratory. The study group ultimately met ten times before disbanding in 1964. Though a meager effort that Adams later called “more or less a private club,” Hof credits it with establishing a foothold for international collaboration in fusion.

For Adams’s part, he returned to the UK in 1961 to direct what was then called the Culham Laboratory. The same year, Jirka Linhart, who led a nascent plasma research effort in CERN’s accelerator division, departed to lead a EURATOM-funded fusion group at the Frascati Laboratory near Rome. These were two of the first centers in what became a more disaggregated civilian fusion research community.

The climate for more integrated efforts improved in the 1970s, as the UK joined the European Community and EURATOM, paving the way for Culham to host JET. By that time, Adams had long since moved on from Culham, passing through high-level positions at the UK’s Ministry of Technology and UKAEA before returning in 1969 to CERN, where he would serve as executive director-general from 1976 to 1980.

Related work

Hof’s article is one of a series of pieces she has recently written on CERN. These also include an article in Physics Today exploring CERN’s motivations for hosting general-education lectures for staff members in the 1960s, and another article in Physics in Perspective, written with Gerardo Ienna and Simone Turchetti, on attempts to suppress political activism at the laboratory.

Hof’s work on fusion is also parallel to the work of a multidisciplinary project on European cooperation in fusion called FusEUrope, which is running from November 2023 to February 2026. Led by historian Roberto Lalli, FusEUrope encompasses four Italian universities and is attempting to integrate computational history of science, social epistemology, history of international relations, oral history, archival research, and public policy analyses.

William Thomas
American Institute of Physics
wthomas@aip.org

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