Behavior of Falling Pebble for Pebble Divertor

Okui, Toshiko; Matsuhiro, K.; Isobe, Michiro; Nishikawa, Masahiro

doi:10.13182/fst01-a11963360

Cited by 6 publications

(4 citation statements)

References 6 publications

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“…The multi-layered ceramic pebble divertor concept was intensively studied in Osaka Univ. in the early 2000s [15][16][17][18]. The cascading pebble divertor using W-coated SiC pebbles or W-coated graphite pebbles was adopted in the conceptual design of an Spherical Tokamak Power Plant (STPP) [19] and an ST-based CTF [20].…”

Section: Main Features Of the Ffhr-b2mentioning

confidence: 99%

Novel features of the helical volumetric neutron source FFHR-b2

Miyazawa¹,

Goto²,

Hamaji³

et al. 2021

Nucl. Fusion

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The compact helical fusion reactor FFHR-b2 is a multipurpose HElical Volumetric Neutron Source (HEVNS) available as the component test facility to test the divertor and blanket systems. In the latest design, three new technologies of the HTS (High-Temperature Superconducting) conductor, the ceramic pebble divertor, and the cartridge-type blanket are adopted. Tin-based functional liquid metals (FLMs) including lithium are considered as the working fluid for the blanket. The FLMs have multi functions of low vapor pressure, low density, low melting point, low corrosiveness, high tritium breeding ratio, and so on. The target construction cost of the FFHR-b2 has been set to 200 billion JPY. The main target of FFHR-b2 is to demonstrate the fusion gain larger than one. To achieve this in a relatively small device, the tangential Neutral Beam Injection (NBI) heating with a moderate energy of 80 keV is adopted for the FFHR-b2. The beam-plasma fusion with 5 MW of NBI heating can produce a fusion power of 5 MW that is larger than the absorbed power of 3 MW.

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Section: Main Features Of the Ffhr-b2mentioning

confidence: 99%

Novel features of the helical volumetric neutron source FFHR-b2

Miyazawa¹,

Goto²,

Hamaji³

et al. 2021

Nucl. Fusion

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“…Therefore, this scattering can be dealt with the square receiver with the sides of ~510 mm and there is enough space to place the receiver of this size. Because this estimation is based on a quite simple assumption, a similar plasma irradiation experiment with the higher electron density, the lighter pebbles and the pebble flow with the higher number density is required [18] to closely investigate this effect of the Coulomb force.…”

Section: ) After Closing the Ball Valve Open The Top Blank Flangementioning

confidence: 99%

Plasma irradiation experiment on the metal pebble flow in the TPDsheet-U

Ohgo

Goto

Takimoto

et al. 2021

Fusion Engineering and Design

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“…The total electric charge can be estimated using the model given in Refs. [17,18]. Within the plasma sheath, ion density n i and the electron density n e can be described by:…”

Section: Force Balance On a Tin Pebblementioning

confidence: 99%

A New Divertor System Using Fusible Metal Pebbles

Ohgo

Goto

Miyazawa

2019

Plasma and Fusion Research

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A fusible metal pebble divertor system named the REVOLVER-D2 is newly proposed here, based on the molten tin jet divertor REVOLVER-D and the pebble divertor concepts. In the REVOLVER-D2, solid tin pebble flows are used as the divertor target. Molten tin pools receive the falling tin pebbles to mitigate the impact of the heavy metal shower. All pebbles are melted in the molten tin pool and recycled into the tin pebbles again. The solid tin pebbles are formed inside the vacuum vessel by the shot tower method using silicone oil pools. This concept enables simultaneous achievement of a high heat load tolerance and a high evacuation efficiency, while mitigating the MHD effects. A high heat load can be removed by the pebble flow if the pebble size is large enough and the velocity is fast enough as with the molten tin jet. Although the charge up of pebbles affects the pebble motion due to the Lorentz force and the Coulomb force, the Lorentz force is negligible if the injection velocity is fast enough. For example, center-to-center pebble distance due to the Coulomb force will be ∼ 4 mm in the case of the injection velocity of 10 m/s if the molten tin pool is placed 2 m under the point where pebbles enter the ergodic layer.

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Behavior of Falling Pebble for Pebble Divertor

Cited by 6 publications

References 6 publications

Novel features of the helical volumetric neutron source FFHR-b2

Novel features of the helical volumetric neutron source FFHR-b2

Plasma irradiation experiment on the metal pebble flow in the TPDsheet-U

A New Divertor System Using Fusible Metal Pebbles

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