Future Zero-Emissions Power Plants: Scientists Collaborate on Development of Commercial Fusion Energy

PPPL physicist Gerrit Kramer with conceptual image of SPARC fusion reactor.
Credit: Collage and Kramer photo by Elle Starkman/PPPL Office of Communications. SPARC image courtesy of Commonwealth Fusion Systems

The U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) is collaborating with private industry on cutting-edge fusion research aimed at achieving commercial fusion energy. This work, enabled through a public-private DOE grant program, supports efforts to develop high-performance fusion grade plasmas. In one such project PPPL is working in coordination with MIT’s Plasma Science and Fusion Center (PSFC) and Commonwealth Fusion Systems, a start-up spun out of MIT that is developing a tokamak fusion device called SPARC.

The goal of the project is to predict the leakage of fast “alpha” particles produced during the fusion reactions in SPARC, given the size and potential misalignments of the superconducting magnets that confine the plasma. These particles can create a largely self-heated or “burning plasma” that fuels fusion reactions. Development of burning plasma is a major scientific goal for fusion energy research. However, leakage of alpha particles could slow or halt the production of fusion energy and damage the interior of the SPARC facility.

New superconducting magnets

Key features of the SPARC machine include its compact size and powerful magnetic fields enabled by the ability of new superconducting magnets to operate at higher fields and stresses than existing superconducting magnets. These features will enable design and construction of smaller and less-expensive fusion facilities, as described in recent publications by the SPARC team — assuming that the fast alpha particles created in fusion reactions can be contained long enough to keep the plasma hot.

“Our research indicates that they can be,” said PPPL physicist Gerrit Kramer, who participates in the project through the DOE Innovation Network for Fusion Energy (INFUSE) program. The two-year-old program, which PPPL physicist Ahmed Diallo serves as deputy director, aims to speed private-sector development of fusion energy through partnerships with national laboratories.

Well-confined

“We found that the alpha particles are indeed well confined in the SPARC design,” said Kramer, coauthor of a paper in the Journal of Plasma Physics that reports the findings. He worked closely with the lead author Steven Scott, a consultant to Commonwealth Fusion Systems and former long-time physicist at PPPL.

Kramer used the SPIRAL computer code developed at PPPL to verify the particle confinement. “The code, which simulates the wavy pattern, or ripples, in a magnetic field that could allow the escape of fast particles, showed good confinement and lack of damage to the SPARC walls,” Kramer said. Moreover, he added, “the SPIRAL code agreed well with the ASCOT code from Finland. While the two codes are completely different, the results were similar.”

MORE of the story / click image TOP of PAGE