Heat management for water-hydraulic systems at ITER remote handling

Highlights: • Divertor area water hydraulics temperature management can be performed in ITER. • Waste heat from Cassette Multifunctional Mover can be dumped into the gallery. • No dedicated cooling required for the Cassette Toroidal Mover. • Heat balance calculations suggest the Toroidal Mover can cool down between operations. -- Abstract: The full exchange of the ITER Divertor is performed with the Divertor Remote Handling System during ITER maintenance campaigns. Equipment with high power density are required to transport the 10-tonne cassettes into and out of the vessel. Water hydraulics has proven to deliver the required power and tracking accuracy. The ambient temperature within the Divertor area (in-vessel) is between 15 °C to 55 °C, which is at the upper limit of allowed temperature range for water hydraulic components. As the Cassette Toroidal Mover (CTM) Hydraulic Power Unit (HPU) must be situated within the CTM chassis and power for the Cassette Multifunctional Mover (CMM) hydraulics is supplied from the transfer cask, they are under increased thermal load from the radioactive components. To address this, a project to investigate solutions for heat management of CTM and CMM hydraulics was undertaken. Multiple heat management methods were analysed and the best solutions for these cases were selected after trade-off analyses. As a result, a traditional liquid/air heat management solution was selected for the CMM and no dedicated cooling was selected for the CTM. Whether the solutions proposed herein are applicable to other ITER systems is discussed.