Cladding for high performance fuel

Contemporary cladding for commercial Generation III (light water reactor) fuel is made from zirconium-based alloys. This family of materials has evolved dramatically over their ∼50 years of existence, leading to an order of magnitude improvement in corrosion resistance. However, in the perspective of a further increased 235U enrichment, or other modifications leading to a significantly higher fissile content of the fuel, other materials that are even more resistant to irradiation damage and corrosion may be required. Cladding materials which degrade more slowly in a severe accident scenario are also desirable The ongoing development of Generation IV technology includes new cladding materials, e.g., SiC composites, which could be “back fitted” into Gen III fuel, providing enhanced performance, economy and safety.Due to the greater complexity of Gen IV technology, in particular its reprocessing infrastructure, the cost of electricity will be higher than for a Gen III LWR operating on a once-through fuel cycle, comparing the true, un-subsidized economic bottom line. Calculations indicate that this financial unbalance, in favor of Gen III LWRs, may be retained for at least hundreds of years.In this perspective, it appears appropriate and attractive to focus more strongly on evaluating Gen IV cladding materials, e.g., SiCf/SiCm composites, for Gen III fuel.

► All modern cladding for Generation III (light water reactor, LWR) fuel is made from zirconium-based alloys. ► With increasing fissile content of LWR fuel, we need materials even more resistant to irradiation and corrosion. ► There is also a desire for cladding materials which are more resistant to a severe accident scenario. ► Generation IV technology includes new cladding types, e.g., SiC composites, which could be “back fitted” into LWR fuel, providing enhanced performance, economy and safety. ► Given the expected (long) life span of LWR technology, it is suggested to focus more strongly on this aspect.