2018 | AFC ACCOMPLISHMENTS 29 Figure 4. Westinghouse Ultrahigh Temperature (>2000°C) Steam Test Apparatus for ATF Cladding. tion methods were demonstrated, and SiGA-TM SiC-SiC cladding retains room temperature strength through 1650°C, and >65% strength to 1900°C, performing significantly better than other ATF concepts, that can show substantial strength loss at 600-900°C. Cladding thermal conduc- tivity was measured up to 1300 °C, with values up to ~30 W/m-K at room temperature. In collaboration with the University of South Carolina, methods were developed to locally heat specimens beyond 1000°C to simulate pellet cladding mechanical interactions and/or perform quench testing. High temperature testing to simulate accident conditions are being pursued in the Westinghouse Ultra HighTemperature facility (Figure 4). Approaches are being developed at a variety of universities and national laboratories and tested for increasing the oxidation resistance of U3Si2. The various options will be tested in the leaker rod test apparatus developed by Westinghouse to verify effectiveness. The commercial introduction of coated cladding with U3Si2 is targeted for 2023 and for SiC with U3Si2 for 2027. In order to meet these very aggressive target dates, changes in the way that Westinghouse and the utilities will license ATF with the Nuclear Regulatory Commission (NRC) will be required. Interactions with the NRC have been initiated and a modified licensing approach utilizing advanced modeling and fuel performance monitoring technologies is being pursued.