The remote maintenance of mechanically attached first wall armour tiles in NET

Abstract Protection of a substantial proportion of the NET First Wall (FW) with low-Z armour is envisaged for at least the early operating period of the machine. This armour will take the form of carbon tiles directly attached to the FW. Complete coverage of the FW will require the installation of 20 000–40 000 tiles. The uncertainties existing in FW operating conditions make it difficult to predict the lifetime of the armour components. However, based on present experience, a number of component failures is to be expected in addition to the general wear by plasma erosion. Bearing in mind the hostile environment within the machine, the remote maintainability of these components is thus of fundamental importance and has strongly influenced their design. Mechanical attachment is considered to be the only viable approach for remotely maintainable armour tiles. A series of tools for mounting and demounting such tiles is currently under development at KfK, Karlsruhe. Handling trials are being carried out on a local FW mock-up to optimise the tile attachment designs for efficient remote handling, to provide input to the overall system design and to facilitate the progressive evolution of effective remote handling tools. Such, tools will subsequently be tested in conjunction with The NET Articulated Boom prototype articulated boom transporter [A. Suppan et al., The Net Articulated Boom] to prove their fitness for purpose. The paper reports the current status of this work and outlines the design and principles of operation of the tools developed. The results and conclusions of the investigations to date, including any practical modifications considered necessary to either the original tile attachment arrangements or the preliminary tool designs, are presented. The philosophy behind the attachment and detachment procedure envisaged is also described.