The hallmarks of the approach to safety embodied in the Integral Fast Reactor (IFR) are: Large margins between the operating conditions and physical safety limits; reliance on passive processes to hold power production in balance with heat removal; and totally passive removal of decay heat, independent of the equipment and structures in the balance-of-plant. Should equipment in the balance-of-plant or control system fail, IFRs will passively regulate their own power so as to remain undamaged for all such initiators, even in the anticipated transient without scram (ATWS) scenarios. Decay heat is removed through a heat-transport path that operates at ambient pressure, is contained along with the reactor core in a double-walled top-entry tank of coolant, has large thermal inertia, is driven by natural convection, is completely independent of the balance-of-plant equipment, and is always in operation.The resulting level of safety exceeds the already acceptable levels attained in current-generation reactors now licensed and operating safely throughout the world.Even for accidents of extremely low probability, lying far beyond the design basis and not even considered in licensing reactors of the current generation, the IFR system has an inherent, designed-in response that prevents release of radioactivity. Processes that are innate consequences of the materials and geometry cause dispersal of fuel early enough to avoid prompt criticality and its accompanying energy release, and assure subcriticality and coolability inside an intact reactor vessel should significant fuel pin failures cause an accumulation of debris.