Consideration of Vacuum Vessel Properties Required for PFRC-type Fusion Reactors

The fourth Princeton Reversed Field Configuration (PFRC-4) is a device designed to produce net power output through the fusion of deuterium and helium-3. Its inner walls would be bathed by 2.45 MeV neutrons as well as synchrotron and Bremsstrahlung radiation. The PFRC-4 device’s vacuum vessel must serve several purposes including: shielding its magnets and any nearby human operators from neutron radiation; extracting useful energy from the incident radiation; and providing compatibility with RF heating. To find a suitable wall material, we report on nuclear, thermal, electrical, optical, and mechanical properties and fabrication techniques for the vessel. Neutron shielding, combined with weight and thickness requirements, strongly support the use of pure B-10 and its light compounds, e.g., boron carbide, and boron nitride. The variability of these properties with temperature and prolonged neutron exposure is described. We identify data not currently available for the materials considered. The dimensions of the vessel, the design of the cooling channels and how their geometry will affect thermal gradients and stresses in the vessel, and methods of manufacturing and assembling the vessel are also discussed. A multi-layer wall which separates the required functions is described.