Laser Cladding Applied to the Construction of PFCs with Integral Tritium Diffusion Barriers

Selection of the Plasma-Facing Component (PFC) material composition is a primary consideration in future fusion reactor design. The PFC materials must not only withstand the harsh operating conditions of the reactor, but the amount of tritium uptake experienced by the PFC during operation is a significant factor. Proper operation, safety and environmental impact mandate that tritium uptake be minimized. Traditional reactor designs include carbon matrix composite (CMC), beryllium (Be) and tungsten (W) as the PFC fabricated as discrete tile units which line the reactor interior surface. Lower Z materials such as C and Be primarily build up tritium by co-deposition with eroded materials while W buildup comes from implantation, trapping and diffusion. For the proposed effort, Nanohmics Inc., an early-stage technology development company (Austin, TX), working in collaboration with Professor Y. C. Shin of Purdue University (West Lafayette, IN) and Drs. Bruce Lipschultz, Dennis Whyte and Graham Wright of MITs Plasma Science Fusion Center (PSFC), are proposing to design new PFC materials that make a significant impact toward minimizing tritium uptake. The proposed effort will be based on recent accomplishments by the Nanohmics/ Purdue partnership in the area of Laser Engineered Net Shaping (LENS) of W clad PFCs. The team successfully demonstrated the ability to clad tungsten on both copper and Inconel substrates with the inclusion of tritium barriers within the tungsten cladding. The success of these recent efforts warrants submission of the current proposal for consideration as a fast track application. The impact of improvements in Plasma Facing Components (PFC) as well as scaling up manufacturing would be significant in realizing the promise of inexpensive power generation from fusion power plants. Billions of dollars are being spent on fusion power as it promises a clean, safe and reliable source for providing energy. The benefits to the public are enormous in terms of less impact to the environment, lower cost per watt of power and significantly safer than todays nuclear fission reactors. Today, PFC researchers have made significant advances in material selection and application. However, as with most early stage research efforts, scaling the concepts to a commercial manufacturing level presents a unique set of challenges and obstacles and there are still significant technical failings of current PFC choices, including but not limited to their weakness in preventing Tritium absorption. However, Nanohmics has the commercial experience and materials manufacturing expertise to present a clear path to the production of high performance PFCs in a reliable and repeatable manner during the Phase I and Phase II effort.