Fabrication of ITER Divertor Cassette Body prototypes

Guerrini, L.; Riccardi, B.; Andrade, José Henrique de; Escourbiac, F.; Felip, Montse; Ferrand, L.; Lorenzetto, P.

doi:10.1016/j.fusengdes.2020.112054

Cited by 4 publications

(2 citation statements)

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“…Passive plates like those in figure 8 also appear compatible with current divertor concepts. For example, a structure similar to the ITER divertor cassette [43] could incorporate stabilizers behind the inner and outer vertical targets.…”

Section: Passive Plate Positioningmentioning

confidence: 99%

Assessment of vertical stability for negative triangularity pilot plants

Guizzo,

Nelson,

Hansen

et al. 2024

Plasma Phys. Control. Fusion

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Negative triangularity (NT) tokamak configurations may be more susceptible to magneto-hydrodynamic instability, posing challenges for recent reactor designs centered around their favorable properties, such as improved confinement and operation free of edge-localized modes. In this work, we assess the vertical stability of plasmas with NT shaping and develop potential reactor solutions. When coupled with a conformal wall, NT equilibria are confirmed to be less vertically stable than equivalent positive triangularity (PT) configurations. Unlike PT, their vertical stability is degraded at higher poloidal beta. Furthermore, improvements in vertical stability at low aspect ratio do not translate to the NT geometry. NT equilibria are stabilized in PT vacuum vessels due to the increased proximity of the plasma and the wall on the outboard side, but this scenario is found to be undesirable due to reduced vertical gaps which give less spatial margin for control recovery. Instead, we demonstrate that informed positioning of passively conducting plates can lead to improved vertical stability in NT configurations on par with stability metrics expected in PT scenarios. An optimal setup for passive plates in highly elongated NT devices is presented, where plates on the outboard side of the device reduce vertical instability growth rates to 16% of their baseline value. For lower target elongations, integration of passive stabilizers with divertor concepts can lead to significant improvements in vertical stability. Plates on the inboard side of the device are also uniquely enabled in NT geometries, providing opportunity for spatial separation of vertical stability coils and passive stabilizers.

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Section: Passive Plate Positioningmentioning

confidence: 99%

Assessment of vertical stability for negative triangularity pilot plants

Guizzo,

Nelson,

Hansen

et al. 2024

Plasma Phys. Control. Fusion

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“…Therefore, it is essential to evaluate the engineering and manufacturing approval process of VV to ensure functional needs such as vacuum leak tightness and structural integrity after manufacturing is finished. The VV's functional acceptability verification phase consists of several tests, collectively knowns as the factory acceptance test (FAT) [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the functional acceptability of the ITER vacuum vessel

et al. 2022

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The International Thermonuclear Experimental Reactor (ITER) vacuum vessel (VV) is one of the critical components of the ITER tokamak fusion reactor. The first sector of the ITER VV was delivered to ITER Organization in 2020, and it is ready to assemble into the tokamak system. After manufacturing the ITER VV, an evaluation should ensure that the components are designed and manufactured to meet the functional requirements, such as vacuum leak tightness and structural integrity. The factory acceptance test (FAT) is essential for confirming acceptance in engineering and manufacturing. This paper introduces the engineering process and technical method of the FAT, which is applied explicitly to the first-of-a-kind ITER VV. We establish a visual inspection, pre-pumping assessment, pressure test, helium (vacuum) leak test, and final dimensional inspection for the FAT. The visual inspection revealed no blockages in the cooling channels of the double walls. The pre-pumping assessment conducted to check the vacuum level and residual gas condition, concluded that the inside of the VV was flawless and thus met the leak test requirements of 1 × 10-8 Pa m3/s. We confirmed no leakage or deformation through the pressure test under reduced pressure. The helium leak test demonstrated engineering soundness with leak tightness of 6.08 × 10-9 Pa m3/s, which is more stringent than the allowable limit. Furthermore, three-dimensional metrology was utilized to determine the as-built dimensions of the manufactured sector. Due to unavoidable weld deformation and tight tolerances, the as-built result does not perfectly meet the assigned tolerance level. Nevertheless, it can be considered as advanced information for assembly with in-vessel components and other sectors. Based on the conformance and suitability of the suggested FAT for the first ITER VV sector, we will determine the acceptability of the upcoming VV sectors, which will be manufactured and delivered by Korea shortly.

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