Silicon carbide nuclear fuel cladding tubes that can withstand extreme temperatures and could completely transform future fuel production technologies have been advanced by General Atomics — Electromagnetic Systems (GA-EMS).

Fuel cladding forms a barrier between the reactor coolant and nuclear fuel pellets, and is essential to protecting fuel while also ensuring the safety of a nuclear power plant. GA-EMS has engineered an effective material for this purpose by incorporating silicon carbide fiber into its new SiGA cladding. Its inclusion reinforces the material similar to the way steel rebar is used to reinforce concrete. The durable engineered silicon carbide composite material can withstand temperatures up to 3,800° F, which is about 500° F hotter than the melting point of the zirconium alloy conventionally used for cladding.

The new cladding formulation effectively contains the solid fuel and any gases that are produced during operation and features a novel sealing technology capable of withstanding pressures far beyond that typical of light water reactor conditions. The company has produced 6 inch long SiGA rodlets and 3 foot cladding samples that meet stringent nuclear power reactor-grade requirements and will undergo irradiation testing at U.S. Idaho National Laboratory facilities. The process has been shown to be scalable to full-length 12 foot fuel rods.

Full demonstration and commercial use of SiGa is expected in early 2030.