In the quest for sustainable and abundant energy, fusion power stands as a beacon of hope. However, the path to harnessing this power is fraught with uncertainties, particularly in the realm of plasma confinement. A recent study published in Nuclear Fusion, led by M. Coleman of EUROfusion and the United Kingdom Atomic Energy Authority, tackles these uncertainties head-on, offering a novel approach that could significantly impact the design and commercial viability of future fusion reactors.
The research focuses on the EU-DEMO, a proposed fusion power plant designed to demonstrate the feasibility of fusion energy. The study introduces a new method for accounting for epistemic uncertainties—those arising from a lack of knowledge—in plasma confinement. This is crucial because plasma confinement directly affects the efficiency and power output of a fusion reactor.
Coleman and his team used the PROCESS code to explore the EU-DEMO design space, considering factors such as aspect ratio, major radius, plasma safety factor, and net electric power. The key innovation is the use of the plasma safety factor at the 95th percentile flux surface, q_95, to apply a design margin on confinement in terms of the H-factor, H. This approach explicitly quantifies the uncertainties, providing a more robust design.
“The inclusion of an explicit and quantified design margin for epistemic confinement uncertainties is a significant step forward,” Coleman explains. “It allows us to insulate the engineering design of future tokamak fusion power plants from these uncertainties, making the design process more reliable and predictable.”
One of the most compelling findings is the impact of this margin on the potential net electric power, $P_{el,net}$, of a reactor. Including a sizeable margin on confinement considerably reduces the potential power output compared to designs that do not account for these uncertainties. However, this trade-off is seen as a necessary step towards ensuring the reliability and commercial viability of fusion power plants.
The study also addresses key shortcomings of previous EU-DEMO designs, particularly the reduction in divertor heat loads during re-attachment. This is a critical aspect of reactor design, as high heat loads can damage reactor components and reduce their lifespan.
The implications of this research are far-reaching. By providing a more robust and reliable design framework, Coleman’s work could accelerate the development of commercial fusion power plants. This, in turn, could revolutionize the energy sector, offering a clean, abundant, and virtually limitless source of power.
As the world grapples with the challenges of climate change and energy security, the need for innovative solutions has never been greater. Coleman’s research, published in the journal Nuclear Fusion, represents a significant step forward in the quest for fusion power, offering a pathway to a more sustainable and secure energy future.
