Conceptual design of a liquid metal limiter/divertor system for the FFHR-d1

Miyazawa, J.; Goto, Takuya; Murase, Takuhei; Ohgo, Takeru; Yanagi, N.; Tanaka, Hirohiko; Tamura, H.; Tanaka, Teruya; Masuzaki, S.; Sakamoto, R.; Yagi, Juro; Sagara, A.

doi:10.1016/j.fusengdes.2017.07.003

Cited by 35 publications

(32 citation statements)

References 35 publications

(44 reference statements)

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“…In the case of the REVOLVER-D, on the other hand, the flow velocity of ∼4 m/s is needed to assure the heat load tolerance [3]. To bridge this gap, numerical simulation has been conducted.…”

Section: Methodsmentioning

confidence: 99%

“…However, it is difficult to sustain divertor detachment in steady state. In the fusion reactor, higher neutron and γ-ray irradiations than in LHD make the performances of measurements and actuators for divertor detachment poor [3]. Instead of the conventional solid divertor, the liquid metal divertor concept is attracting attention.…”

Section: Introductionmentioning

confidence: 99%

“…A new concept named the REVOLVER-D (Reactor oriented Effectively VOLumetric VERtical Divertor) consisting of liquid metal shower jets has been proposed for the helical fusion reactor FFHR [3,11]. The REVOLVER-D consists of molten tin shower jets inserted into the ergodic region of the plasma as a limiter/divertor.…”

Section: Introductionmentioning

confidence: 99%

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Study on Jets Stabilized by Inserting Internal Flow Resistances for the Liquid Metal Divertor in the Helical Fusion Reactor

Ohgo

Miyazawa

Goto

et al. 2018

Plasma and Fusion Research

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The stabilization effect of the Internal Flow Resistances (IFR) inserted into water jets has been investigated in order to apply the liquid metal divertor to the helical fusion reactor, FFHR. A high heat load exceeding 20 MW/m 2 is one of the important issues for the divertor in the nuclear fusion reactor. A new concept of ergodic limiter/divertor called the REVOLVER-D has been proposed for FFHR. This divertor is expected to tolerate a high heat load larger than a few tens of MW/m 2 . Jets narrow after acceleration by gravity and transform to droplets due to the surface tension instability. Stabilization of jets is an important issue for realizing the REVOLVER-D. In this paper, stabilization of jet by various IFR has been examined. Here, the "sheath jet" is defined as a jet with an IFR inside. Experiments on sheath jet have been carried out and the stabilization effect of IFR has been confirmed. Numerical simulations on sheath jet using ANSYS have been carried out. It is shown that the velocity of the sheath jet reaches the terminal velocity, which is proportional to 0.36 ± 0.01 power of the flow rate and −0.26 ± 0.01 power of the outer circumference of the IFR.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Study on Jets Stabilized by Inserting Internal Flow Resistances for the Liquid Metal Divertor in the Helical Fusion Reactor

Ohgo

Miyazawa

Goto

et al. 2018

Plasma and Fusion Research

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“…Therefore, estimation of impurity flux released from the limiter and its transport in the plasma are critical issues. REVOLVER-D uses tin because of its much lower vapor pressure than other metallic materials with low melting point [1,9]. A rough estimation of vapor flux is given by P v / √ 2πmkT under the assumption of an equilibrium of particle flux on the surface.…”

Section: Influence Of Impuritymentioning

confidence: 99%

“…New concepts of tokamak divertor systems have been proposed utilizing modifications of the magnetic field structure and the divertor plates. A concept design of an advanced divertor, REVOLVER-D, for a helical fusion reactor has been proposed based on Large Helical Device (LHD) [1]. This concept design uses a shower of melting tin as a plasma-facing component.…”

Section: Introductionmentioning

confidence: 99%

Application of EMC3-EIRENE to Estimation of Influence of a Liquid Metal Limiter on an LHD-Type Fusion Plasma

Kawamura

Miyazawa

Goto

et al. 2018

Plasma and Fusion Research

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Recently, a new limiter concept with liquid metal for a helical fusion reactor was proposed. This work present a modeling study to understand the influence of the limiter to the plasma and to find critical parameters for the liquid limiter concept. EMC3-EIRENE code is applied to a limiter configuration of a vertical column formed with plane surfaces at the inboard side of the Large Helical Device (LHD). The calculation results indicate that heat load on the helical divertor plates is significantly reduced when the limiter is inserted into the ergodic layer even without impurities. However, the influence of impurity radiation is too large in some cases. In order to achieve a large reduction of divertor flux and to avoid a large reduction of core electron temperature, parameter scans with limiter position and sputtering yield were performed. The results suggest that the limiter position is a critical parameter for acceptable degradation of the core and sufficient reduction of divertor flux.

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Progress in the Conceptual Design of the Helical Fusion Reactor FFHR-d1

et al. 2018

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The LHD-type helical fusion reactor FFHR has been studied to realize steady-state fusion power generation without a need for current drive and free from disruption. The conceptual design studies of FFHR are steadfastly progressing based on the presently ongoing experiments in the Large Helical Device (LHD). In order to enhance the attractive features of the base option of FFHR-d1A, which is similar to LHD, configuration optimization is being considered for FFHR-d1C. Slight modification of the helical coil trajectory gives an improved condition both for the plasma confinement and the MHD stability. In order to overcome the difficulty for construction and maintenance associated with the three-dimensional structure, innovative ideas are being explored for the superconducting magnet, divertor, and blanket. For the superconducting helical coils, the joint-winding method confirms a fast manufacturing process. The helical divertor is reexamined and practical feasibility is discussed. The maintenance method of the helical divertor and the helically-segmented breeder blanket is a serious issue and a plausible solution is proposed.

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Conceptual design of a liquid metal limiter/divertor system for the FFHR-d1

Cited by 35 publications

References 35 publications

Study on Jets Stabilized by Inserting Internal Flow Resistances for the Liquid Metal Divertor in the Helical Fusion Reactor

Study on Jets Stabilized by Inserting Internal Flow Resistances for the Liquid Metal Divertor in the Helical Fusion Reactor

Application of EMC3-EIRENE to Estimation of Influence of a Liquid Metal Limiter on an LHD-Type Fusion Plasma

Progress in the Conceptual Design of the Helical Fusion Reactor FFHR-d1

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