•A global background radiation source and cesium threat source were simulated in the Fort Indiantown Gap training facility model
•Excellent agreement was found between Shift and MAVRIC and various detector locations throughout the model
•This validation builds confidence in Shift’s simulation capabilities and prepares Shift to be used more frequently in homeland security applications in the future
•An LEU-fueled core was simulated in a detailed HFIR model for a full fuel cycle in both Shift and VESTA
•Shift was found to agree well with VESTA, to within 100 pcm at all timesteps
•Shift high-performance parallel decomposition enables this simulation to be completed in ~21.5 hours, versus ~252 hours for VESTA
