Development of a systematic, self-consistent algorithm for the K-DEMO steady-state operation scenario

Kang, Junsu; Park, J.M.; Jung, L.; Kim, S.K.; Wang, J.; Lee, Chan-Young; Na, D. H.; Im, Kyongok; Na, Y.-S.; Hwang, Yong Seok

doi:10.1088/1741-4326/aa7072

Cited by 19 publications

(6 citation statements)

References 22 publications

(25 reference statements)

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“…Options include a large, barely advanced EU-DEMO baseline with high recirculating power [13] and the somewhat-advanced 'stepladder' approach [14,15] with longer pulse length and more aggressive technology and physics assumptions. Japan proposes a more advanced SlimCS device [16], while South Korea targets its KSTAR program on the K-DEMO device [17,18]. In the United States, the original ARIES design [6] has been updated with various 'advanced and conservative tokamak' (ACT) versions [19], while proposals are also made for more compact lower power designs with the ARC [20] and ST pilot plant [21] facilities.…”

Section: Introduction-the At Pathmentioning

confidence: 99%

The advanced tokamak path to a compact net electric fusion pilot plant

et al. 2021

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Physics-based simulations project a compact net electric fusion pilot plant with a nuclear testing mission is possible at modest scale based on the advanced tokamak concept, and identify key parameters for its optimization. These utilize a new integrated 1.5D core-edge approach for whole device modeling to predict performance by self-consistently applying transport, pedestal and current drive models to converge fully non-inductive stationary solutions, predicting profiles and energy confinement for a given density. This physics-based approach leads to new insights and understanding of reactor optimization. In particular, the levering role of high plasma density is identified, which raises fusion performance and self-driven ‘bootstrap currents’, to reduce current drive demands and enable high pressure with net electricity at a compact scale. Solutions at 6–7 T, ∼4 m radius and 200 MW net electricity are identified with margins and trade-offs possible between parameters. Current drive comes from neutral beam and ultra-high harmonic (helicon) fast wave, though other advanced approaches are not ruled out. The resulting low recirculating power in a double null configuration leads to a divertor heat flux challenge that is comparable to ITER, though reactor solutions may require more dissipation. Strong H-mode access (x2 margin over L–H transition scalings) and ITER-like heat fluxes are maintained with ∼20%–60% core radiation, though effects on confinement need further analysis. Neutron wall loadings appear tolerable. The approach would benefit from high temperature superconductors, as higher fields would increase performance margins while potential for demountability may facilitate nuclear testing. However, solutions are possible with conventional superconductors. An advanced load sharing and reactive bucking approach in the device centerpost region provides improved mechanical stress handling. The prospect of an affordable test device which could close the loop on net-electric production and conduct essential nuclear materials and breeding research is compelling, motivating research to validate the techniques and models employed here.

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Section: Introduction-the At Pathmentioning

confidence: 99%

The advanced tokamak path to a compact net electric fusion pilot plant

et al. 2021

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“…Here, the normalized beta (β N ) represents the plasma performance, where β N = β • aB T /I p , and β = ⟨p⟩/(B 2 /2µ 0 ). The β N of performance-enhanced plasmas can be compared to whether it approaches the target β N of a demonstration fusion power plant (DEMO) design (2.8 in the K-DEMO first phase [33], 2.6 and 3.8 in the EU DEMO1 and DEMO2 design options [34], and 3.4 in the JA DEMO steady-state plasma [35]). The database analysis indicates that the auxiliary heating power (P heat ) and the RMP coil current (I RMP ) are the two most relevant factors determining β N during the RMP-driven suppression phase.…”

Section: Introductionmentioning

confidence: 99%

Integrated RMP-based ELM-crash-control process for plasma performance enhancement during ELM crash suppression in KSTAR

et al. 2023

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The integrated resonant magnetic perturbation (RMP)-based ELM-crash-control process aims to enhance the plasma performance during the RMP-driven ELM crash suppression, where the RMP induces an unwanted confinement degradation. In this study, the normalized beta (βN) is introduced as a metric for plasma performance. The integrated process incorporates the latest achievements in the RMP technique to enhance βN efficiently. The integrated process triggers the n = 1 edge-localized RMP (ERMP) at the L-H transition timing using the real-time machine learning (ML) classifier. The pre-emptive RMP onset can reduce the required external heating power for achieving the same βN by over 10 % compared to the conventional RMP onset. During the RMP phase, the adaptive feedback RMP ELM controller, demonstrating its performance in previous experiments, plays a crucial role in maximizing βN during the suppression phase and sustaining the βN-enhanced suppression state by optimizing the RMP strength. The integrated process achieves βN up to ~2.65 during the suppression phase, which is ~10 % higher than the previous KSTAR record but ~6 % lower than the target of the K-DEMO first phase (βN = 2.8), and maintains the suppression phase above the lower limit of target βN (= 2.4) for ~4 s (~60 τE). In addition to βN enhancement, the integrated process demonstrates quicker restoration of the suppression phase and recovery of βN compared to the adaptive control with the n = 1 conventional RMP (CRMP). The post-analysis of the experiment shows the localized effect of the ERMP spectrum in radial and the close relationship between the evolution of βN and the electron temperature.

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“…The considered design parameters of these devices, along with those of JA-DEMO and K-DEMO are shown in Table 3. Tobita et al, 2019; data of CFETR largely extracted from Zhuang et al, 2019; data of K-DEMO extracted from Kim et al, 2015;Neilson et al, 2014 andKang et al, 2017. A major difference between the EU DEMO and CFETR (Zhuang et al, 2019) design concepts is that the CFETR design assumes steady-state operation, with a significant current-drive fraction, and hence low-density operation (which is a challenge for the divertor).…”

Section: Demonstration Reactors Based On Extrapolations From Itermentioning

confidence: 99%