An Assessment of the Penetrations in the First Wall Required for Plasma Measurements for Control of an Advanced Tokamak Plasma Demo

A demonstration tokamak is an essential next step toward a magnetic fusion-based reactor. One based on advanced tokamak plasmas is especially appealing because of its relative compactness. However, many plasma measurements will be required to provide the necessary signals to feed to ancillary systems to protect the device and control the plasma. This technical note addresses the question of how much intrusion into the blanket system will be required to allow the measurements needed to provide the information required for plasma control. All diagnostics will require, at least, the same shielding designs as planned for ITER, while having the capability to maintain their calibration through very long pulses. Much work is required to define better the measurement needs and the quantity and quality of the measurements that will have to be made, and how they can be integrated into the other tokamak structures.