JET-R(96)02

High Heat Flux Exposure Tests on 10mm Beryllium Tiles Brazed on Actively Cooled Vapotron made from CUCRZR

10 mm thick Beryllium tiles brazed to a CuCrZr vapotron have been shown to withstand power densities of 20 MW /m2 for up to 2 seconds without catastrophic failure of the braze. Some of the tile surface was above liquidus temperature for up to 900 ms. A strong Be I line intensity is observed approximately 500 ms after the start of surface melting. The emissivity of the surface shows strong variations with time and location once the surface has been above liquidus. The surface damage is quite limited, however cracks are observed after several exposures above liquidus. The reflectivity for wavelengths to which the CCD camera is sensitive changes strongly once the surface has been above melting. This might cause saturation effects leading to misinterpretation. The experimental results are being used successfully by ITER and NET to benchmark numerical models.
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JETR96002 2.53 Mb