Organizing Wendelstein 7-X device operation

The super conducing stellarator Wendelstein 7-X (Bosch a al., 2017) started its first operational phase in October 2015 at the Max-Planck-Institute for Plasma Physics in Greifswald with the goal to verify that a stellarator magnetic confinement concept is a viable option for a fusion power plant, i.e. showing confinement comparable to tokamaks and running in steady state operation. Between 2015 and 2018 the first three experimental campaigns (operational phases) OP1.1, OP1.2a and OP1.2b of the W7-X stellarator have been successfully completed. Roughly 13 Months of operational time have been accumulated and have already shown the impressive capability and reliability of W7-X in achieving the physical and technical goals as set by the project. The working group Device Operation (DO) has implemented an organizational structure and workflow to ensure safe and reliable operation of the W7-X device. DO is responsible for planning and executing the commissioning and operation of the W7-X device. The operations plan is based on the physics planning which is a selection of individual physics proposals keeping in mind the technical limitations of W7-X. The operations plan is iterated between the lead physicists and device operation team (DOT). The "technischer Leiter vom Dienst" (TLvD or Engineer in Charge) plays a central role within the DOT in coordinating and supervising the technical operation of W7-X. To ensure safe and reliable operation of W7-X several procedures have been implemented and improved. This involves commissioning templates, checklists, procedures for e.g. plasma heating energy release, operation malfunction cards, logbooks, coordination meetings, duty-on-call and shift-planning. This paper will summarize the organizational aspects of W7-X technical operation as performed in the first three phases. It will also provide an outlook on the upcoming OP2 (actively cooled divertor) with the requirements for technical operation regarding commissioning and operation towards steady state plasma operation.