Operation of TEXTOR-94 with tungsten poloidal main limiters

• In TEXTOR-93, experiments have been performed with the upper and lower poloidal limiter blocks made of vapour 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 found no restriction for operation at any density with auxiliary heating. For Ohmic conditions the same density with testlimiters could be reached. Under siliconized conditions no severe accumulation of tungsten in the plasma centre could be detected. The blocks could in general stand surface temperatures below 1700 K. Most of them survived also temperatures above 3000 K without exfoliation. However, some blocks showed severe damage by melting or exfoliation probably due to insufficient contact of the tungsten layer with the graphite.

Nyckelord

coating

high-Z material

limiter materials

TEXTOR 94

tokamak

poloidal limiter

tungsten

heat load

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)