Nathaniel Fisch, the director of the Princeton Program in Plasma Physics, and the team of researchers at the Princeton Plasma Physics Laboratory (PPPL) received $1,499,953 in funding on Feb. 14 from the United States Department of Energy’s Advanced Research Projects Agency–Energy (ARPA-E) for their project on refining an innovative form of fusion energy.
The PPPL’s research holds significant promise for the global effort to develop novel types of clean energy technologies.
Fusion energy is a type of nuclear reaction in which two light atomic nuclei combine and create a heavier nucleus. This class of reactions generate heat that can in turn be channeled to produce vast amounts of electricity. This innovative mode of energy production has typically revolved around the fusion reaction between two distinct forms of hydrogen: deuterium and tritium, or DT fusion. DT fusion produces energy harnessed by a tokamak, a donut-shaped magnetic device.
Fisch’s project, titled “Economical Proton-Boron11 Fusion,” optimizes fusion reactions, but with a novel spin. Instead of relying on the classic DT fusion reaction, his team’s project involves the fusion between a proton (a hydrogen atom nucleus) and a boron-11 nucleus, the latter of which is composed of five protons and six neutrons.
Protons and boron-11 particles are not only ubiquitous and affordable, but the fusion of the two particles — known as a pB11 reaction — generates energy without radioactive waste. This is at the core of what makes Fisch’s work so groundbreaking: Instead of generating radioactive waste, pB11 reactions yield energy in the form of alpha particles, or non-radioactive helium nuclei. In contrast, traditional modes of fusion energy — including DT reactions — produce ample amounts of radioactivity, which can exert detrimental effects on human health and the environment.
Despite the comparative advantages of pB11 reactions, the fusion of protons and boron-11 particles remains rife with challenges, primarily owing to the incredibly high temperatures necessary to execute the reaction. These reaction conditions can be induced under conditions of hundreds of millions of degrees which necessitate vast energy expenditures, according to Fisch.
“To release fusion energy, one needs to confine ions hot enough to undergo fusion for a time long enough to recoup the energy it took to heat them to high temperatures,” Fisch wrote in an email to The Daily Princetonian. “The pB11 reaction has a smaller cross section, so that means that it takes longer to recoup the invested energy, which means that you must confine them somehow for longer.”
“On top of that, if the ions are so hot, then the electrons will become similarly hot, which means they will radiate away in short wavelength light (X-rays) the energy that you are trying to confine,” Fisch wrote, emphasizing that the high temperatures carry their own set of challenges with respect to the preservation of the energy produced by pB11 reactions.
Fisch’s project aims to resolve this predicament by devising fusion reaction designs that minimize the energy losses associated with pB11 reaction conditions while seeking to amplify their reactivity.
For instance, the plasma in the tokamak could be rotated such that the boron-11 ions are confined at a considerable distance away from the lighter protons. This arrangement would enable only the most energetic protons to interact with boron. These circumstances would also provide a cooler environment for pB11 reactions, while reducing the radioactive loss of harvested energy and potentially paving the way toward a cost-efficient method of pB11 fusion.
Ian Ochs, a former Jacobus Fellow and a postdoctoral student on Fisch’s team, previously…
Read More: PPPL receives $1.5M from Department of Energy for Fusion Energy Project