General Atomics Electromagnetic Systems (GA-EMS) just announced that it has completed preliminary development of four individual performance models in support of its SiGA silicon carbide composite nuclear fuel cladding technology. One of the four individual models utilized to analyze the fiber architecture within SiGA cladding.
GA-EMS is approaching completion of a thirty-month contract with the U.S. Department of Energy (DoE) to deliver individual models for nuclear-grade SiGA materials to serve as the basis of a future digital twin. This modelling and simulation capability is intended to help accelerate the process of qualifying nuclear fuel and licensing for current and next generation reactor materials.
SiGA is a silicon carbide (SiC) composite material that has great hardness and the ability to withstand extremely high temperatures. It has been used for industrial purposes for decades. It is now used as the basis for the development of nuclear reactor fuel rods that can survive temperatures far beyond that of current materials.
GA-EMS said that the four individual physics-informed models it has developed are able to capture the complex mechanical response of SiGA fuel-rod cladding while exposed to irradiation. A multi-scale modelling approach was utilized where each individual model covers a different length scale – from a mechanism-based microscale model to a reactor system level model. In the future, these individual models will be combined into one integrated model which is called a digital twin.
Scott Forney is the President of GA-EMS. He said, “A digital twin is a virtual representation of a physical object or system - in this case our SiGA cladding nuclear fuel system. When complete, this digital twin will allow researchers to predict SiGA performance inside a nuclear reactor core. This will reduce fuel development and testing costs and shorten the time it will take to get regulatory approval for this revolutionary technology, without sacrificing safety.”
Christina Back is the vice president of GA-EMS Nuclear Technologies and Materials. She said that “We have been able to expedite development and verification of the individual models by leveraging the expertise at Los Alamos National Laboratory and Idaho National Laboratory. Our work integrally involves dedicated laboratory testing as we develop each performance model. We look forward to continuing to the next phase to bring these individual models together and incorporate them into a greater digital twin framework. Utilization of the framework to apply the separate effects models appropriately will bring a new level of sophistication and accuracy to efficiently predict fuel performance.”
GA-EMS has successfully made silicon carbide nuclear fuel cladding tubes. The company's technology incorporates silicon carbide fiber into its cladding tubes. The combination creates an incredibly tough and durable engineered silicon carbide composite material which can withstand temperatures up to three thousand degrees °F. This is about five hundred degrees hotter than the melting point of zirconium alloy currently in use.
Last July, General Atomics announced it had manufactured the first batch of full-length twelve-foot SiGA silicon carbide composite tubes designed for conventional pressurized water reactors. Previously it had created six-inch long SiGA rodlets and three-foot cladding samples that meet the stringent nuclear power reactor-grade requirements and will undergo irradiation testing at DoE's Idaho National Laboratory.
GA had originally developed its SiGA composite for its Energy Multiplier Module (EM2) small modular reactor (SMR) design. This is a modified version of its Gas-Turbine Modular Helium Reactor (GT-MHR) design.
In February 2020, Framatome and GA agreed to evaluate the possibility of using SiGA in fuel channel applications through thermomechanical and corrosion testing. Their long-term goal is to demonstrate that the irradiation of a full-length fuel channel in support of licensing and commercialization.