Progress in the engineering design and assessment of the European DEMO first wall and divertor plasma facing components

Barrett, T.; Ellwood, G.; Pérez, Germán; Kovari, M.; Fursdon, M.; Domptail, F.; Kirk, Simon; McIntosh, S.; Roberts, Sigrid C.; Zheng, S.; Boccaccini, Lorenzo Virgilio; You, J.-H.; Bachmann, Christian; Reiser, J.; Rieth, M.; Visca, E.; Mazzone, G.; Arbeiter, Frederik; Domalapally, Phani Kumar

doi:10.1016/j.fusengdes.2016.01.052

Cited by 81 publications

(27 citation statements)

References 19 publications

(32 reference statements)

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“…The supporting substructure is assumed to be steel, in keeping with divertor cassette designs for ITER [7] and the current DEMO baseline for first wall components, although the design is still evolving and alloys based on zirconium, chromium, and vanadium have also been discussed [14].…”

Section: Why Focus On the Structural Material?mentioning

confidence: 99%

Refractory metals as structural materials for fusion high heat flux components

Hancock

Homfray

Porton

et al. 2018

Journal of Nuclear Materials

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Tungsten is the favoured armour material for plasma facing components for future fusion reactors, but studies examining the use of tungsten or other refractory metals in the underlying cooled structures have historically excluded them, leaving current concepts heavily dependent on copper alloys such as copper chrome zirconium. This paper first outlines the challenge of selecting an appropriate alternative material for this application, with reference to historical selection methodology and design solutions, and then reexamines the use of refractory metals in the light of current design priorities and manufacturing techniques. The rationale for considering refractory alloys as structural materials is discussed, showing how this is the result of relatively small changes to the logic previously applied, with a greater emphasis on high temperature operation, a re-evaluation of current costs, a relaxation of absolute activation limits, and the availability of advanced manufacturing techniques such as additive manufacturing. A set of qualitative and quantitative assessment criteria are proposed, drawing on the requirements detailed in the first section; including thermal and mechanical performance, radiation damage tolerance, manufacturability, and cost and availability. Considering these criteria in parallel rather than sequence gives a less binary approach to material selection and instead provides a strengths and weaknesses based summary from which more nuanced conclusions can be drawn. Data on relevant material properties for a range of candidate materials, including elemental refractory metals and a selection of related alloys are gathered from a range of sources and collated using a newly developed set of tools written in the python language. These tools are then used to apply the aforementioned assessment criteria and display the results. The lack of relevant data for a number of promising materials is highlighted, and although a conclusive best material cannot be identified, refractory alloys in general are proposed as worthy of further investigation.

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Section: Why Focus On the Structural Material?mentioning

confidence: 99%

Refractory metals as structural materials for fusion high heat flux components

Hancock

Homfray

Porton

et al. 2018

Journal of Nuclear Materials

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“…FEM were indeed performed in the most conservative case for which no compliant layer is used. It is noted that the elastic criterion is generally known to be conservative and that the implementation of a FGM as an interlayer would increase this reserve factor [12].…”

Section: Design Optimizationmentioning

confidence: 99%

Status on the W monoblock type high heat flux target with graded interlayer for application to DEMO divertor

Richou

Gallay

Chu

et al. 2017

Fusion Engineering and Design

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The divertor is the key in-vessel plasma-facing component being in charge of power exhaust and removal of impurity particles. In DEMO, divertor target must survive an environment of high heat fluxes (~Up to 20 MW/m² during transient) and neutron irradiation. This paper presents an advanced actively cooled concept aiming to reduce the thermal stress at the bond interface due to distinct difference in thermal expansion between tungsten and CuCrZr which may cause a mismatch during thermal cycling. This concept is based on the use of a W/Cu functionally graded material (FGM) interlayer instead of the copper interlayer. Mock-up geometrical definition was performed based on available technology to manufacture FGM in a monoblock configuration, with regard to Eurofusion divertor DEMO project specifications and minimizing as much as possible thermomechanical stresses during operation. The interlayer (~25 µm) is made with PVD (Plasma Vapor deposition) and composed of continuous gradient of W from 100% at the interior part of the tile to 0% at the external part while Cu varies from 0% to 100%. Hot isotactic pressure is realized to assemble the CuCrZr tube to W tile equipped with graded material. With Infrared (SATIR) and US nondestructive examinations, mock-ups show good interface quality. Relevancy of low thickness FGM as a bonding solution between armour and structural materials for divertor application will be checked in a near term future with high heat flux tests.

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“…Tungsten and low activation ferritic-martensitic steels (EUROFER) have been selected as reference material for plasma facing material and structural materials, respectively. The former has been chosen due to its excellent thermophysical properties (high thermal conductivity, high melting point, sputtering resistance) and the latter due to the lack of active elements and its strength under the neutron flux given in the reactor [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

“…This sacrificial layer will be held up by an Eurofer structure, which also supports in turn the breeding blankets on the other side [3]. Therefore, it is necessary to develop WEurofer joints capable to withstand the conditions given in the reactor.…”

Section: Introductionmentioning

confidence: 99%