Thermal and mechanical behaviour of diagnostic windows subjected to intense heat fluxes

The diagnostic windows of a machine for thermonuclear fusion experiments ar e basically subjected to atmospheric pressure and thermal loads due to plas ma radiation. The glass or ceramic windows capable of withstanding the expe cted design loads become critical components if a highly radiative plasma i s present near the window, as experienced in RFX during pulses with plasma current in the range of 1 MA. The transient thermal and mechanical analyses of windows having different shapes and made from different materials have been carried out. The results in terms of stress distributions showed that high tensile stresses can be present in the window volume shielded from rad iation by the mounting flanges. The calculation of the failure probabilitie s gave a thorough knowledge of the behaviour and safety margins of the diag nostic windows. (C) 2000 Elsevier Science B.V. All rights reserved.