The first wall in JET - status and perspectives

The problems of the wall facing the plasma, of the vacuum vessel and of the limiters, among the most difficult ones that have to be faced in high power machines are discussed. Operating for longer times than a few seconds demands solutions compatible with continuous operation. The problem of the erosion of the first surface will limit the life time of the elements used and necessitates remote handling replacement if working in active conditions is envisaged. The erosion is obviously the main cause for the impurities accumulating in the plasma and may be one of the major obstacles to ignition and thermo-nuclear power. (author)