Image-based deformation measurements of fusion divertor armour under high heat flux loading

Engineering components within a fusion reactor are subjected to extreme environments including high heat flux, strong magnetic fields and neutron irradiation. Simulations are required to predict the in-service lifetimes of fusion components and ensuring credibility of these simulations requires validation over testable domains. Divertors are responsible for extracting heat and ash from the fusion reaction and protecting the vacuum vessel from thermal loads. In this work, we conduct an image-based experimental assessment of a divertor armour component design under a steady-state, high heat flux of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mo>~</mml:mo> <mml:mspace width="0.25em"/> <mml:mn>5</mml:mn> <mml:mspace width="0.25em"/> <mml:mi>MW</mml:mi> <mml:mo stretchy="false">/</mml:mo> <mml:msup> <mml:mrow> <mml:mi>m</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> under vacuum conditions. The heat flux was applied to the water-cooled component using the Heating by Induction to Verify Extremes (HIVE) facility at the UK Atomic Energy Authority. We used digital image correlation (DIC) to measure the surface strain of the component and thermocouples to measure the temperature during the high heat flux pulse. We used synthetic image deformation simulations to analyse sources of random and systematic errors in our DIC measurements and to select DIC processing parameters for subsequent analysis. Our results show that DIC is a valuable tool for the validation of multi-physics simulations by providing information about the geometrical arrangement of components as well as high resolution data indicating areas of disagreement between the simulation and experiment. The results of our study are the first image-based simulation validation dataset for a divertor component under fusion relevant conditions.