Liquid tin limiter for FTU tokamak

Vertkov, А.V.; Lyublinski, I.E.; Zharkov, M. Yu.; Mazzitelli, G.; Apicella, M. L.; Иафрати, М.

doi:10.1016/j.fusengdes.2017.01.041

Cited by 40 publications

(13 citation statements)

References 6 publications

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“…Such set-ups retain the tin melt inside a porous matrix (e.g., a fine tungsten mesh) by capillary forces. The CPS arrangement is also proposed to hinder, e.g., melt splashing due to magneto-hydrodynamic forces that would occur in a fusion reactor or a high-flux linear plasma device [1,2,9] by subdividing the melt into small compartments. Due to the orders of magnitude lower currents and weak magnetic fields in the plasma source used here, a CPS was also considered unnecessary for the experiments presented in this article.…”

Section: Sample Preparation and Crucible Designmentioning

confidence: 99%

“…It might be possible to discern these processes by only varying the plasma flux while keeping in particular the D 2 gas pressure constant. Unfortunately, with the plasma source used here, it is currently not easily possible to vary those parameters independently (see also [9]). Strong roughening of the sample surface (i.e., formation of the spongelike layers shown in Figure 4) should in principle increase the active surface for chemical erosion.…”

Section: Sn Erosionmentioning

confidence: 99%

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Deuterium retention in solid and liquid tin after low-temperature plasma exposure

et al. 2020

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Recently, plasma-facing components based on liquid metals were proposed for a prospective nuclear fusion reactor in order to circumvent challenges that occur for solid metal components, such as erosion lifetime, neutron embrittlement or transient overloading. One candidate material is liquid tin. We present a systematic study of the behavior of solid and liquid tin exposed to a lowtemperature deuterium plasma at temperatures between 300 and 515 K, focusing on deuterium retention and thermal release as well as on tin erosion and re-deposition. We find strong variations of deuterium depth profiles, release spectra, and erosion rates, which are correlated to dramatic changes in the surface morphology. In particular, we find evidence for massive gas bubble formation in tin, which can lead to the evolution of a thick, sponge-like layer for tin exposed to deuterium plasma just below the melting point, and to the rapid formation of a macroscopic gas pocket below liquid tin. We present evidence for strongly temperature-dependent chemical erosion of tin by deuterium plasma in the solid state. In the liquid state, a high tin erosion rate occurs, which is apparently induced by ejection of tin microdroplets. Furthermore, we observed strong plasmaassisted, low-temperature wetting of tin on tungsten near the melting point of tin. We tentatively propose the hypothesis that all of the observed effects may be influenced by tin-deuterium chemistry, e.g., the formation and de-composition of stannane molecules.

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Section: Sample Preparation and Crucible Designmentioning

confidence: 99%

Section: Sn Erosionmentioning

confidence: 99%

Deuterium retention in solid and liquid tin after low-temperature plasma exposure

et al. 2020

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“…For the fusion reactor, such coolants as water, liquid metal (lithium), and gas (argon) are usually considered as heat-transfer agents [1]. At present, it has been proposed to use fine water mist spray carried by the gas flow as a coolant [33,34]. For a singlephase coolant (lithium, water, helium), the convective heat transport is determinant, and the heat conduction of coolant is of primary importance.…”

Section: Choice Of Heat-transfer Agentmentioning

confidence: 99%

Comparative Analysis of Lithium First Wall Concepts for Tokamak with Reactor Technologies

et al. 2021

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When developing the stationary fusion reactor, an unresolved issue is the design of its intra-chamber plasma-facing elements. It has now become obvious that among the materials conventionally used for intra-chamber elements, there are no solid structural materials that would meet the requirements for the long-term operation under the effect of the flux of fusion neutrons (14 MeV) with a density of ~1014 cm–2 s–1 and the heat flux with a power density of 10–20 MW/m2. An alternative solution to this problem is the use of liquid metals as a plasma-facing materials, and, first of all, the use of lithium, which has a low atomic number (low charge number Z). Other easily-melting metals are also considered, which have higher Z number, but lower saturation vapor pressure than lithium. This will make it possible to create the long-lived, heavy-to-damage and self-renewing surface of the intra-chamber elements, which will not contaminate the plasma. The main ideas of the alternative concept of the intra-chamber elements can be formulated based on the comprehensive analysis of the problems and requirements arising during the development of intra-chamber elements of the stationary reactor, for example, the DEMO-type reactor. The article presents the analysis of the possible design of the lithium-coated intra-chamber elements and discusses the main ideas of the lithium first wall concept for the tokamak with reactor technologies.

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“…Due to the Sn corrosion, a thin W coating in the order of few hundred microns is mandatory to protect all the surfaces in contact with the LM. The limited literature on the topic suggests good compatibility between W and Sn [9][10][11].…”

Section: Geometry and Materialsmentioning

confidence: 99%

CPS Based Liquid Metal Divertor Target for EU-DEMO

et al. 2020

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Power exhaust is a key mission in the roadmap to the realization of a future fusion reactor. Among the different solutions, the use of liquid metals as plasma facing materials are of interest due to their potential increased lifetime. Several liquid metal limiters have been successfully tested in the Frascati Tokamak Upgrade over the last 10 years. Liquid materials such as lithium and tin have been investigated using capillary porous systems (CPSs), and their impact on plasma performance has been explored. From such experience, a liquid metal divertor (LMD) concept design, CPS-based, is here proposed. Tin has been preferred as plasma facing material. The proposed LMD would operate, in low evaporative regime, with matching heat exhausting capabilities to those of the baseline ITER-like divertor. Continuous refilling of the CPS is guaranteed with a reservoir at the back of the unit, where the metal is kept liquid through a gas heating circuit. The study has been carried out using ANSYS and the thermal results will be shown. All the design choices are compatible with the current materials and the constraints adopted for the DEMO W divertor. Using such configuration, thermal loads up to 20 MW/m2 are exhausted while keeping the surface temperature below 1250 °C. The design foresees values of pressure, temperature and flow rate of the water coolant in the same range expected for the W DEMO divertor, thus facilitating the integration of such solution in the current cassette design. Technological and practical aspects are addressed, i.e. tin corrosion and CPS wettability. Possible solutions to prevent tin corrosion, and its compatibility with structural materials, will be outlined.

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Liquid tin limiter for FTU tokamak

Cited by 40 publications

References 6 publications

Deuterium retention in solid and liquid tin after low-temperature plasma exposure

Deuterium retention in solid and liquid tin after low-temperature plasma exposure

Comparative Analysis of Lithium First Wall Concepts for Tokamak with Reactor Technologies

CPS Based Liquid Metal Divertor Target for EU-DEMO

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