A 350 GHz, 0.25 MW Robust Gyrotron Optimized for High Volume Production for Net Electric Fusion Reactors

As work continues on the design and fabrication of ITER experimental fusion reactor there is new focus on the next generation commercial fusion reactors. Several design concepts have been put forward including the DEMOnstration power station followed by the PROTOtype power station and other concepts for compact reactors. Electron Cyclotron Resonance Heating (ECRH) and Electron Cyclotron Current Drive (ECCD) will be vital tools in all these reactors both for plasma control and heating. Based on the preliminary designs most of these reactors will require 20 – 40 MW of power in the 250 – 350 GHz range (depending on chosen magnetic field) for ECRH and ECCD. We propose the development of a 350 GHz, 0.25 MW gyrotron as a robust, reliable and economical alternative to a 1 MW system at 350 GHz. The development of a reliable product that can be mass produced will eventually pave the way for an overall cost reduction of the EC system. While we have not performed a complete trade-off analysist to accurately determine if a 0.3 MW or a 0.25 MW would be optimal from a production point, a 1 MW device at 350 GHz would be prohibitively expensive just considering a 220 mm bore, 15 T superconducting magnet. Though the initial cost of four 0.25 MW units will likely be ~1.5 times the cost of a single 1 MW unit, the increase in reliability, and lower repair cost per tube will eventually lead to a lower total ownership cost. We propose to fabricate key parts of the gyrotron using Additive Manufacturing to reduce the time and cost of part fabrication achieved by minimizing the number of joints and other machining operations. The proposed system will advance the state of the art significantly and pave the way for successful adoption of such compact systems in commercial reactors. This successful demonstration of the key physics and engineering aspects will pave the way for the fabrication and testing of a continuous wave device with funding support from a sponsor. Summary for members of Congress: Bridge 12 Technologies proposes to develop a high frequency gyrotron (microwave generator) for heating nuclear fuel in a fusion reactor for clean energy production.