July 25, 2023
Reliable, high-performance operation of present-day tokamaks relies on proper conditioning of the plasma facing components. A common method, known as boronization,
involves the application of thin boron coatings to in-vessel surfaces. These boron films improve plasma performance. However, boron has been found in present-day devices and laboratory experiments to retain non-negligible amounts of hydrogen isotopes. This is of significant concern since it projects to high tritium retention estimates. Tritium retention in-vessel is a concern for two reasons: (1) it prevents manned access of the device for maintenance; (2) it limits the amount of tritium in circulation as part of the fuel cycle and reduces the amount available for injection during plasma pulses. In addition, boron dust is not easily removed, and will continue to accumulate over the operational lifetime. No data exists on boron dust tritium retention. This proposal studies deuterium retention in boron dust, using deuterium as a surrogate for experimental simplification, and describing the operational and safety profile of boronization as a tool for fusion power plants.