High Efficiency Gyrotron Technology Development

Gyrotrons are required for electron cyclotron heating of plasmas in fusion power plants. Key requirements are low cost and high efficiency. Government agencies indicate that efficiency must exceed 55% with cost reductions exceeding half the current cost. The cost reduction and efficiency must be achieved to make fusion power plants viable replacements for carbon-base power plants. Smart power supplies will also be required to ensure optimum gyrotron performance under all operating scenarios. Calabazas Creek Research Inc. (CCR) developed direct couplers that convert the circuit mode into a low loss mode in waveguide inside the gyrotron. This reduces the cost of each gyrotron installation by more than $600K. CCR also developed multi-stage depressed collectors that are predicted to increase gyrotron efficiency by more than 60%. This program will integrate these two technologies into gyrotrons needed for fusion power plants. Multi-stage depressed collector requires smart power supplies able to optimize multiple voltages and currents in real time to achieve high efficiency. This program will develop machine learning for gyrotron power supplies. The Phase I program will install and upgrade computer codes for designing multi-stage depressed collectors. These will be used to convert an existing two-stage collector design to three stages to increase efficiency. The program will also modify existing gyrotron direct output couplers for compatibility with depressed collectors. Machine learning programs will be investigated to optimize gyrotron efficiency during operation. It is estimated that 200 ľ 300 gyrotrons will be required for each fusion power plant. These must operate non-stop for months at a time and use dramatically less power than current gyrotrons. Fusion power offers the promise of clean, unlimited power for the future, eliminating carbon- based power sources.