Present status of the ITER real-time Plasma Control System development

ITER will be the world's largest magnetic confinement tokamak fusion device and is currently under construction in southern France. The ITER Plasma Control System (PCS) is a fundamental component of the ITER Control, Data Access and Communication system (CODAC). It will control the evolution of all plasma parameters that are necessary to operate ITER throughout all phases of the discharge. The design and implementation of the PCS poses a number of unique challenges. The timescales of phenomena to be controlled spans three orders of magnitude, ranging from a few milliseconds to seconds. Novel control schemes, which have not been implemented at present-day machines need to be developed, and control schemes that are only done as demonstration experiments today will have to become routine. In addition, advances in computing technology and available physics models make the implementation of real-time or faster-than-real-time calculations to forecast and subsequently to avoid disruptions or undesired plasma regimes feasible. A further novel feature is a sophisticated event handling system, which provides a means to deal with plasma related events (such as MIlD instabilities or LH transitions) or component failure. Finally, the schedule for design and implementation poses another unique challenge. The beginning of ITER operation will be in late 2020, but the conceptual design activity has already commenced as required by the on-going development of diagnostics and actuators in the domestic agencies and the need for integration and testing. In this paper, an overview about the functional requirements for the plasma control system will be given. The main focus will be on the requirements and possible options for a real-time framework for ITER and its interfaces to other ITER CODAC systems (networks, other applications, etc.). The limited amount of commissioning time foreseen for plasma control will make extensive testing and validation necessary. This should be done in an environment that is as close to the PCS version running the machine as possible. Furthermore, the integration with an Integrated Modeling Framework will lead to a versatile tool that can also be employed for pulse validation, control system development and testing as well as the development and validation of physics models. An overview of the requirements and possible structure of such an environment will also be presented.