Control-oriented core-SOL-divertor model to address integrated burn and divertor control challenges in ITER

Graber, Vincent; Schuster, Eugenio

doi:10.1016/j.fusengdes.2023.113635

Cited by 2 publications

(4 citation statements)

References 20 publications

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“…where e = 1.622 × 10 −19 C and ε 0 = 8.854 × 10 −12 F/m. Similarly to the approaches taken in [13,22], the volume average of P ei was approximated in (14).…”

Section: The Core-plasma Modelmentioning

confidence: 99%

“…Similarly to the SOLPS4.3 parameterizations [12], the two-point model connects conditions at the separatrix to conditions near the divertor. In contrast to the model proposed in this work, the model in [14] relied on phenomenological quantities, such as the divertor retention time, which absorb many unknown relations (similarly to the global energy confinement time but without any widely used scaling laws that can be extrapolated to ITER and other future machines [16]). The values of these phenomenological quantities would have to be obtained by fitting the CSD model to either experimental data or transport simulations.…”

Section: Introductionmentioning

confidence: 99%

“…In prior work [13,14], a core-SOL-divertor (CSD) model was developed by coupling the energy and density response models of the core-plasma region to a two-point model [15] of the SOL-divertor region (the model in [14] also included a neutral-particle response model for the divertor-plasma region). Similarly to the SOLPS4.3 parameterizations [12], the two-point model connects conditions at the separatrix to conditions near the divertor.…”

Section: Introductionmentioning

confidence: 99%

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Divertor-safe nonlinear burn control based on a SOLPS parameterized core-edge model for ITER

Graber,

Schuster

2024

Nucl. Fusion

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For ITER operations, the range of desirable burning-plasma regimes with high fusion power output will be restricted by various operational constraints. These constraints include the saturation of ITER’s various heating and fueling actuators such as the neutral beam injectors, the ion and electron cyclotron heating systems, the gas puffing system, and the deuterium-tritium pellet injectors. In addition to these actuator constraints, the H-mode power threshold, divertor detachment, and the heat load on the divertor targets may apply limitations to ITER’s operational space. In this work, Plasma Operation Contour (POPCON) plots that map the aforementioned constraints to the temperature-density space are used to investigate which constraints are most limiting towards accessing regimes with high fusion power output. The presented POPCON plots are based on a control-oriented core-edge model that couples the nonlinear density and energy response models for the core-plasma region with SOLPS4.3 parameterizations for conditions in the edge-plasma regions (scrape-off-layer and divertor). Using this control-oriented core-edge model, a nonlinear burn controller, which aims to regulate the plasma temperature and density in the core-plasma region, is constructed in this work. This controller is augmented with an online optimization scheme that governs the control references such that the plasma can be guided towards regimes with high fusion powers while protecting the divertor targets from dangerously high heat loads. A closed-loop simulation study illustrates the capability of this burn control scheme.

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“…where e = 1.622 × 10 −19 C and ε 0 = 8.854 × 10 −12 F/m. Similarly to the approaches taken in [13,22], the volume average of P ei was approximated in (14).…”

Section: The Core-plasma Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Divertor-safe nonlinear burn control based on a SOLPS parameterized core-edge model for ITER

Graber,

Schuster

2024

Nucl. Fusion

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“…The vacuum vessel containing the plasma in the ITER tokamak has the divertor located at its bottom, which channels out heat and ash from the fusion reaction and minimizes contamination by plasma while protecting the surrounding walls from thermal and neutronic loads [6]. Tungsten is the preferred candidate material for use in the plasma-facing component (armour material) of the divertor cassette in planned fusion reactors such as ITER [7,8], as it has excellent high-temperature properties such as high melting point (3422 • C), high threshold energy for sputtering (E th ~200 eV for deuterium) i.e., low erosion rate, high thermal stress resistance, high thermal conductivity, low induced activation, low swelling, and low tritium retention [9,10]. Different methods of W armour plate fabrication have been explored in recent years, including rolling [11] and plasma spray [12].…”

Section: Introductionmentioning

confidence: 99%

Effect of He Plasma Exposure on Recrystallization Behaviour and Mechanical Properties of Exposed W Surfaces—An EBSD and Nanoindentation Study

Bhattacharyya,

Thompson,

Hoang

et al. 2023

Metals

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Fusion reactors are designed to operate at extremely high temperatures, which causes the plasma-facing materials to be heated to 500 °C to 1000 °C. Tungsten is one of the target design materials for the plasma-facing diverter components in Tokamak designs, such as ITER, because of its excellent high-temperature strength and creep properties. However, recrystallization due to high temperatures may be detrimental to these superior mechanical properties, while exposure to He plasma has been reported to influence the recrystallization behaviour. This influence is most likely due to the Zener effect caused by He bubbles formed near the surface, which retard the migration of grain boundaries, while at the same time modifying the surface microstructure. This paper reports a study of the effect of plasma exposure at different sample temperatures on the recrystallization behaviour of W at different annealing temperatures. The characterization after plasma exposure and annealing is pursued through a series of post-exposure annealing, followed by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) characterization and nanoindentation to determine the mechanical properties. Here, it is shown that the hardness is closely related to the recrystallization fraction, and that the plasma exposure at a sample temperature of 300 °C slows down the recrystallization more than at higher sample temperatures of 500 °C and 800 °C. Atomic force microscopy (AFM) was subsequently used to determine any changes in pile-up height around the nanoindents, to probe any indication of changes in hardenability. However, these measurements failed to provide any clear evidence regarding this aspect of mechanical behaviour.

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Control-oriented core-SOL-divertor model to address integrated burn and divertor control challenges in ITER

Cited by 2 publications

References 20 publications

Divertor-safe nonlinear burn control based on a SOLPS parameterized core-edge model for ITER

Divertor-safe nonlinear burn control based on a SOLPS parameterized core-edge model for ITER

Effect of He Plasma Exposure on Recrystallization Behaviour and Mechanical Properties of Exposed W Surfaces—An EBSD and Nanoindentation Study

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