A New Divertor System Using Fusible Metal Pebbles

Ohgo, Takeru; Goto, Takuya; Miyazawa, J.

doi:10.1585/pfr.14.3405050

Cited by 7 publications

(6 citation statements)

References 17 publications

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“…In parallel with the research on the use of LM for the diverter, [15][16][17][18][19][20][21] the use of LM for the blanket has been extensively studied and, as one of the LM candidates for the blanket use, Sn-Bi(bismuth)-Li-Er(erbium) alloy (SBLE) has been considered. SBLE is mainly composed of Sn-Bi, which has a low melting point and is admixed with Li and Er; those are used for tritium breeder and stainless steel corrosion suppressor, respectively.…”

Section: Introductionmentioning

confidence: 99%

Bubbling phenomenon of liquidized Sn–Bi–Li–Er alloy under hydrogen plasma exposure

Tamura

Miyazawa²,

Masuzaki³

et al. 2022

Jpn. J. Appl. Phys.

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A laboratory-scale inductively coupled plasma apparatus investigated the behavior of liquid Sn–Bi–Li–Er alloy (SBLE) under hydrogen (H2) plasma exposure. By exposing the liquid SBLE to H2 plasma, the bubbling of liquid SBLE and pulsive H2 pressure increase were observed. Moreover, plasma density, i.e., ion flux, increased both bubble size and H2 pressure-spike. The simultaneous measurement of a high-speed camera and mass spectrometry concluded that the bubble was formed by H2 accumulation, and ~38% of hydrogen ion flux contributed to the H2 accumulation. Lithium hydride may be considered the bubble sphere’s origin from X-ray photoelectron spectroscopy measurement of droplets produced from the ruptured bubble sphere. From the experimental results, the bubble formation mechanism was discussed.

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Section: Introductionmentioning

confidence: 99%

Bubbling phenomenon of liquidized Sn–Bi–Li–Er alloy under hydrogen plasma exposure

Tamura

Miyazawa²,

Masuzaki³

et al. 2022

Jpn. J. Appl. Phys.

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“…It should be noted that this <GHD> is estimated for the case without the pebble divertor. In this study, 70 % of the divertor heat load is assumed to be absorbed by the pebble divertor and the rest of 30 % goes to the helical divertor, as in the former studies [8,9]. With the pebble divertor, <GHD> can be reduced to 6.3 ´ 0.3 ~ 1.9 MW/m 2 .…”

Section: Device Parameters Of the Ffhr-b3mentioning

confidence: 99%

Coordinated design of the cartridge-type blanket and the ceramic pebble divertor for the helical reactor FFHR-b3

Miyazawa¹,

Goto²,

Hamaji³

et al. 2021

Nucl. Fusion

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The cartridge-type blanket for the helical reactor has been updated and named the CARDISTRY-B3. Together with this, the ceramic pebble ergodic limiter/divertor system named the REVOLVER-D3 has been adopted in the design. There was a difficulty in fabricating the blanket cartridges due to the first wall shape with three-dimensional surface. This difficulty has been removed by introducing the slit first wall, where the first wall surface is formed by alternately stacking solid metal plates and porous plates made of metal or ceramic. The liquid metal flowing inside the blanket cartridge oozes out through the porous plates and forms the surface flow covering the first wall. Solid target plates for the helical divertor has been omitted, because the divertor region is already covered and protected by the liquid metal surface flow. The liquid metal freely falls inside the blanket cartridges by the gravity force and then exhausted to the pool set on the lower port. The ceramic pebbles, which are dropped to the inboard-side ergodic layer to form the flowing limiter divertor, also flow into the liquid metal pool. The pebbles and liquid metal are individually elevated again by screw conveyers. Since the free surface of the liquid metal is exposed to the plasma, the vapor pressure of the working liquid metal should be low enough. Ternary or quadruple alloys, which include Li, Sn, Pb (or Bi), and Er, have been selected as the candidates of the functional liquid metal for the CARDISTRY-B3 that satisfies the requirements of low vapor pressure, low density, low melting point, and high tritium breeding ratio. In this study, the coordinated design of CARDISTRY-B3 and REVOLVER-D3 for the FFHR-b3 is presented. The FFHR-b3 is one of the design options that aims at demonstration of 100 MW net electricity with two times larger devise size than LHD.

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“…The REVOLVER-D3 is a newly proposed limiter/divertor system using falling massive ceramic pebbles as the Plasma Facing Material (PFM). This concept is based on the former concepts of the REVOLVER-D [12] and the REVOLVER-D2 [13,14], which adopt the melted tin shower jets and the solid tin pebbles, respectively, for the PFM. The multi-layered ceramic pebble divertor concept was intensively studied in Osaka Univ.…”

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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A New Divertor System Using Fusible Metal Pebbles

Cited by 7 publications

References 17 publications

Bubbling phenomenon of liquidized Sn–Bi–Li–Er alloy under hydrogen plasma exposure

Bubbling phenomenon of liquidized Sn–Bi–Li–Er alloy under hydrogen plasma exposure

Coordinated design of the cartridge-type blanket and the ceramic pebble divertor for the helical reactor FFHR-b3

Novel features of the helical volumetric neutron source FFHR-b2

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