Operation of TEXTOR-94 with a Tungsten Poloidal Main Limiter System

In TEXTOR-94 experiments have been performed with the upper and lower poloidal limiter tiles made of vapor sprayed (VSP) tungsten (about 0.5 mm) deposited on graphite with a Rhenium interlayer. A series of discharge conditions have been performed (density scan, scan of the auxiliary heating power, radius scan). There has been no restriction for operation at any density with auxiliary heating. For Ohmic conditions the same density with testlimiters - and even higher - could be reached. At high discharge power losses by radiation no severe accumulation of tungsten in the plasma centre could be detected. The blocks could in general stand surface temperatures below 1700 K. However, most of them survived also temperatures above 3000 K without exfoliation. However, some blocks showed severe damage by melting or exfoliation probably due to not sufficient contact of the tungsten layer with the graphite.