US-based start-up Commonwealth Fusion Systems (CFS) announced that the results of rigorous performance tests of its toroidal field (TF) magnet, a key component of the company’s planned SPARC fusion power plant, have been successfully validated by an independent panel of reviewers under the US Department of Energy’s (DOE’s) Milestone-Based Fusion Development Program.
CFS has raised almost $3bn in capital since it was spun-out from the Massachusetts Institute of Technology (MIT) in 2018. It will use the funds to complete its SPARC demonstration tokamak under construction in Devens, Massachusetts. It will also progress development work on its planned 400 MWe ARC fusion power plant in Chesterfield County, Virginia, with grid connection expected in the early 2030s.
In April, CFS said it had begun assembling its SPARC tokamak, which had been under development for years. CFS began by manufacturing SPARC’s superconducting magnets based on large-scale prototypes. CFS has already installed ancillary equipment around SPARC. This includes the systems to power and cool the tokamak’s super-strong magnets, the diagnostic sensors to monitor the fusion process, and the heating system to turn SPARC’s hydrogen fuel into a plasma for the fusion process. However, this may not be enough for CFS to meet its target of producing first plasma in 2026 and net fusion energy shortly after.
DOE‘s Milestone programme leverages public-private partnerships to catalyse the development of a new commercial fusion power industry. The milestones and completion criteria that are selected represent key achievements to de-risk the technologies, and to demonstrate real and tangible progress towards the advancement of commercial fusion. The milestones are assessed by an independent board of technical experts from national labs, and DOE reimburses costs only upon satisfactory technical milestone achievement.
The recent award to CFS provided confirmation that the company’s first production high-field D-shaped TF magnets passed a battery of acceptance tests for inclusion in the SPARC machine. These magnets use proprietary design and manufacturing processes and are based on High Temperature Superconductors (HTS). Over a month of rigorous performance tests were performed that mimic operational modes in SPARC; the results were reviewed and validated by a team of DOE magnet experts experienced in fusion, high energy accelerator, and material science magnets.
As a result, DOE awarded CFS $8m, the biggest amount given to any company to date in its Milestone programme. CFS is also now eligible to receive $15m from the first budget period of the DOE Milestone programme. The programme currently has $46 million appropriated for the first budget period. The TF magnet award is the third milestone that CFS has achieved in the programme.
The magnet technology was previously validated in a series of TFMC tests in 2021, and these tests showed that the full production magnets installed in the SPARC demonstration fusion machine are meeting requirements. The magnets are now in regular serial production at the manufacturing facility. The same design is anticipated for the ARC power plant.
“DOE’s Milestone programme is designed to promote progress in the development of commercial fusion energy through a rigorous review process of key technical milestones that will build confidence in this nascent industry,” said CFS CEO and Co-founder Bob Mumgaard. “Fusion will ultimately help to define the future of global energy security, economic competitiveness, and human development for generations to come. American ingenuity has helped lay the groundwork, and ongoing DOE support will help to accelerate the full realisation of this groundbreaking technology.”
Following the successful completion and validation of the TF milestone, US Secretary of Energy Chris Wright visited the CFS headquarters in Devens, Massachusetts, where the company is manufacturing their high-temperature superconducting (HTS) magnets and completing construction of SPARC.
“Fusion has the potential to be transformative for the world’s energy security,” said Wright. “The Department of Energy is committed to ensuring American leadership in fusion power by accelerating innovation and collaboration across the government, our National Labs, and the private sector.”
