The NuScale Advanced Passive Safety Design

NuScale Power is designing an advanced passive nuclear power plant that does not rely on any external sources of power or coolant for safety. Accordingly, the NuScale design inherently prevents the types of issues which led to fuel damage at the Fukushima Daiichi facility. This paper presents an overview of the advanced passive safety systems implemented in the NuScale nuclear power plant. During normal operation, each NuScale containment is fully immersed in a water-filled stainless steel lined concrete pool that resides underground. The pool, housed in a Seismic Category I building, is large enough to provide 30 days of core and containment cooling without adding additional water. After 30 days, the decay heat generation is sufficiently small that natural convection heat transfer to air on the outside surface of the containment coupled with thermal radiation heat transfer is completely adequate to remove core decay heat for an indefinite period of time. These passive safety systems can perform their function without requiring an external supply of water, power, or generators.