Sizing Calculation of the ITER Compressed Air Supply for Tokamak Cooling Water Valve Actuators
M. Szabo (TU Delft - Mechanical Engineering)
Nicolas Schiliuk – Mentor (ITER)
J.W.R. Peeters – Mentor (TU Delft - Energy Technology)
S.A. Klein – Graduation committee member (TU Delft - Energy Technology)
R. Delfos – Graduation committee member (TU Delft - Large Scale Energy Storage)
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Abstract
This thesis presents the design and performance assessment of the Compressed Air System for Tokamak Cooling (26CATC) at ITER, which operates the Tokamak Cooling Water System (TCWS) - a critical component ensuring safe reactor cooling. The research addresses the challenge of ensuring reliable pneumatic valve operation within a highly constrained environment characterized by long piping networks, magnetic field limitations, and strict safety requirements. The main design gaps identified concern valve stroking times, excessive
air consumption at several interface points, and the need for effective overpressure protection. To address these, a steady-state compressible flow model was developed using AFT Arrow, supported by detailed data extraction from 3D CAD geometries and automated processing tools to calculate flow resistances and mass flow rates for over a thousand valves. The methodology incorporated actuator and torque data to compute stroke times and evaluate compliance with safety and operational criteria. Results showed that while most valves meet the required performance, 21 safety-critical valves fail to achieve the necessary stroking times, requiring design modifications such as local pressure tanks or spring-assist systems. Additionally, more than 60% of consumption scenarios exceed predefined flow rate limits, highlighting the need for capacity optimization at several interface points. The network’s overpressure protection was successfully addressed through the integration of 168 Pressure Reducing Valves, ensuring safe operation under all loading conditions. Overall, the study demonstrates that while the current design framework provides a robust foundation for the 26CATC system, targeted design improvements and further validation are required to guarantee full compliance and operational reliability in ITER’s demanding environment.