Assessment of Beryllium Tile Size in ITER EHF First Wall

This research reveals the results of a thermo-mechanical stress analysis of the beryllium and CuCrZr components of the Enhanced Heat Flux (EHF) First Wall (FW). Under the EHF thermal load, differential thermal expansion at the Be/CuCrZr interface can potentially lead to failure of the beryllium tiles. We have shown that the stress profile in both beryllium and CuCrZr can be improved by reducing the dimensions of the beryllium tiles covering the FW panels.In addition, our research investigated a failure condition for the FW finger’s design. Specifically, we assessed the temperature profile at the CuCrZr/water interface of the EHF FW finger in the event of a single failed tile. This was done in order to determine whether or not the critical heat flux condition occurs in the coolant channel after a single tile failure. Assuming the failure of a single tile between 11.75mm and 50mm in size, temperature profiles were generated assuming flat, rectangular water cooling channels. It was found that tile failure from the edges of the finger resulted in considerably higher temperatures than tile failures at the middle of the finger. Failure of a tile along the edge of the finger may cause catastrophic failure, as the critical heat flux condition occurred at the CuCrZr/water interface even for tiles as small as 11.75mm in size.