Magnetic field and power consumption constraints for compact spherical tokamak power plants

Schoofs, Frank; Todd, T.N.

doi:10.1016/j.fusengdes.2022.113022

Cited by 8 publications

(6 citation statements)

References 79 publications

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“…8 and the neutron energy multiplication factor set to f m = 1.24 (consistently with our choice of fusion blanket described below [34] and with typical ranges of f m = 0.9-1.4, depending on the blanket configurations [25,[35][36][37].…”

Section: Thermal Power and Net Electric Powermentioning

confidence: 99%

Economically optimized design point of high-field stellarator power-plant

Prost,

Volpe

2024

Nucl. Fusion

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High Temperature Superconductors expand the design space of stellarator power-plants toward high magnetic fields B, enabling compact major radii $R$. The present paper scans the space of B, R and other design parameters, finding solutions that are promising from a physics and engineering standpoint, while minimizing the capital cost of the power-plant and the levelized cost of fusion electricity. Similarly, it identifies minimum-cost design points for next-step burning plasma stellarator experiments of fusion gain 1 < Q < 10. The study assumes advanced stellarator configurations of reduced aspect ratio, heated by Neutral Beam Injection. Plasma-facing, flowing liquid metal walls protect it from high heat and neutron fluxes. The study relies on analytical first-principle calculations, and established zero-dimensional empirical scaling laws. Power flows are illustrated by Sankey diagrams. Plasma operating contours are used to determine the reactor’s start-up path. Sensitivity analyses are conducted to identify the most critical reactor parameters within physics, engineering and costing, quantifying their influence on the economics of the power plants. Such 0D study suggests that the assumed next generation HTS, flowing liquid metal walls, and advances in compact plasma configurations could lead to an ignited stellarator power-plant of aspect ratio A ~ 4, R ≤ 4 m, B > 9 T, and normalized plasma pressure β ~ 5 % would minimize both the cost of electricity and capital cost while achieving a net electric power of about 1 GW.

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Section: Thermal Power and Net Electric Powermentioning

confidence: 99%

Economically optimized design point of high-field stellarator power-plant

Prost,

Volpe

2024

Nucl. Fusion

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“…The fueling efficiency is defined in [1] as the ratio of the tritium fueling rate to the tritium injection rate 4 :…”

Section: Understanding Fueling Efficiency (η F ) Burn Fraction (F B )...mentioning

confidence: 99%

“…In a recent preliminary study on plasma and FPP parameters for an ST FPP carried out by Schoofs and Todd [4], three possible design variants for an ST FPP are identified: compact, balanced, and conservative. The compact design (R 0 = 3.26 m) exploits a high toroidal magnetic field (B T,max = 23 T) at the expense of a lower predicted toroidal magnet lifetime (1.3 FPY).…”

Section: Step-ebbmentioning

confidence: 99%

“…This tritium is initially extracted by the purge gas (N 2 ). The TES then separates tritium from the nitrogen purge gas and the helium produced by the 6 Li(n, t) 4 He reactions. Furthermore, the HX present in the ARC-class OFC is replaced by a turbine in the STEP-class OFC to enable a direct power generation cycle [3].…”

Section: Step-ebb Fcmentioning

confidence: 99%

“…where τ * p = τp 1−R , τ p is the particle confinement time, R is the particle recycling coefficient, I fus is the fusion reactivity integral defined in equation ( 5) of [85], n 0 is the electron density (in 10 20 m −3 units), and T 0 is the electron temperature (in keV). The same values for R, density, and temperature profile (obtained from [4]) were used for all three variants. Table 8.…”

Section: Tritium Self-sufficiency In Step-ebbmentioning

confidence: 99%

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Modeling and analysis of the tritium fuel cycle for ARC- and STEP-class D-T fusion power plants

Meschini,

Ferry,

Delaporte-Mathurin

et al. 2023

Nucl. Fusion

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The limited tritium resources available for the first fusion power plants (FPPs) make fuel self-sufficiency and tritium inventory minimization leading issues in FPP design. This work builds on the model proposed by M. Abdou et al. \cite{abdou2020physics}, which analyzed the fuel cycle of a DEMO-class FPP with a time-dependent system-level model. Here, we use a modified version of their model to analyze the fuel cycle of an ARC-class tokamak and two versions of a STEP-class tokamak. The ARC-class tokamak breeds tritium in a FLiBe liquid immersion blanket (LIB), while the STEP-class tokamak breeds tritium utilizing either a liquid-lithium blanket design or an Encapsulated Breeding Blanket (EBB). A time-dependent system-level model is developed in Matlab Simulink~\textregistered\hspace{.2em} to simulate the evolution of tritium flows and tritium inventories in the fuel cycle. The main goals of this work are to assess tritium self-sufficiency of the ARC- and STEP-class designs and to determine quantitative design requirements that can be used to analyze the adequacy of a proposed fuel cycle system. These design requirements are aimed at achieving a low tritium inventory doubling time ($t_d$) and a low start-up inventory ($I_{\mathrm{startup}}$) while keeping the required tritium breeding ratio (TBR$_r$) as low as possible. We also consider how improvements in fuel cycle technology and plasma operations affect TBR$_r$ and $I_{\mathrm{startup}}$. The model results show that TBR$_r$ for ARC- and STEP-class FPPs should be achievable if the tritium burn efficiency (TBE) reaches 0.5-1\% (TBR$_r <$ 1.2). This assumes significant, but attainable, improvements over current abilities. However, the model results indicate that a FPP must achieve ambitious performance targets, including FPP availability $>$70\%, tritium processing time $<$4~h, and the implementation of direct internal recycling. If future research yields major improvements to achievable TBE, it may be possible to achieve tritium self-sufficiency while operating at lower availability and without implementing DIR.

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