Fueling control system integration and control simulation for ITER start of research operation

• GIS and PIS fueling models integrated into ITER’s Plasma Control System framework. • Actuator Manager coordinates fueling, enabling smooth gas–pellet transitions. • RAPDENS simulator models plasma density evolution with fueling and actuator failures. • Simulations show robust handling of actuator loss via flow reallocation strategies. • Initial GIS and PIS independent feedback control established. ITER's Start of Research Operation (SRO) operations target the generation of plasmas reaching ∼7.5 MA for durations exceeding 100 seconds. Effective control of fueling, density, impurity dosing, edge-localized modes (ELMs), and H-mode transitions is critical. To enable model-based design, the Gas Injection System (GIS) and Pellet Injection System (PIS) have been developed as models such that a complete fueling control system can be designed to address the complex requirements and challenges unique to ITER. These challenges involve lag-time due to lengthy gas lines, fueling efficiency decay at high plasma temperatures and densities, synchronization of multiple actuators, and balancing ELM pacing with fueling needs. An Actuator Manager (AM) coordinates the GIS and PIS operations to optimize performance. The GIS and PIS models utilize 1-D particle transport models for the gas flow and diffusion through the pipe as well as the pellet transport through the Flight Tubes (FTs), which have been implemented within the Plasma Control System Simulation Platform (PCSSP). Furthermore, the particle deposition into the plasma as well as the plasma-neutral interactions are modeled through the RApid Plasma DENsity Simulator (RAPDENS). The results presented here demonstrate the successful integration of the GIS, PIS, AM, and RAPDENS for modeling the smooth transitions between fueling modes, and effective handling of actuator failures. This paper presents the architectural design, simulation results, and future strategies for optimizing fueling control during ITER's Augmented First Plasma operations.