May 3, 2016 – Silicon carbide-based materials could be a winning alternative to zirconium alloys commonly used in fuel and core structures in today’s light water reactors, according to preliminary findings of a team led by Yutai Katoh of Oak Ridge National Laboratory. “Fuels and core structures in current light water reactors are vulnerable to catastrophic failure in severe accidents,” Katoh said. This is largely because of the rapid oxidation kinetics of zirconium alloys in a water vapor environment at very high temperatures. Continuous silicon carbide fiber-reinforced matrix ceramic composites offer outstanding safety benefits because the material reacts with water vapor about 1,000 times slower and retains its strength at temperatures exceeding 2,000 degrees Celsius. This allows it to proportionately reduce generation of heat and hydrogen. ORNL’s approach features a dual-purpose coating on the silicon carbide composite cladding wall to alleviate corrosion and gas permeation issues.
ORNL’s dual-purpose coating potentially offers key advantages for fuel and core structures in light water reactors.
