Maintenance of in-vessel components in NET

The maintenance requirements for NET in-vessel components are concisely stated and discussed. The general maintenance scheme based on an oblique handling of first wall/blanket segments from the top of the machine, and the use of an in-vessel handling unit (IVHU) for intervention on smaller internal parts such as first wall protection tiles is described. Mean maintenance times are estimated assuming both scheduled and unexpected maintenance of components. Finally, required handling equipment is defined and ongoing or envisaged development described. (author)