Technology Update

A New Level of Plant Resiliency

The NuScale power plant offers mission critical facilities a level of certainty for achieving the “Five 9s” (99.999 percent) for highly reliable power. A 924 MWe (gross) NuScale 12-module power plant can assure 154 MWe net power to a dedicated microgrid at 99.95% reliability over the 60-year lifetime of the plant, while 77 MWe (gross) of power can be provided at a remarkable 99.98% reliability. The unique resilience features of the NuScale power plant include:

Black-Start and Island Mode: Following a loss of offsite power event, a single NuScale Power Module™ (NPM) can be black-started from cold conditions and continue to power the entire plant without the plant being connected to the grid. This is referred to as operating in Island Mode.

First Responder Power: If a loss of transmission system grid occurs, the NuScale plant employs variable (0% to 100%) steam bypass so that all 12 modules can remain at power operating in Island Mode and be available to provide electricity to the grid as soon as the grid is restored.

Resilience to Natural Events: In the NuScale plant, the modules and fuel pool are located below grade in a Seismic Category 1 Building that is capable of withstanding a Fukushima type seismic event and can withstand hurricanes, tornados, and floods.

Reactor Barriers Diagram

Resilience to EMP/GMD Events: The NuScale plant has numerous geomagnetic disturbance (GMD) and electromagnetic pulse (EMP) resilience features, including plant safety equipment that is electrically isolated from the main plant distribution system, a reactor vessel shielded by a stainless steel containment vessel, a GMD/EMP hardened concrete reactor building with steel liner and reinforced steel rebar, and widespread use of optical fiber links that are not susceptible to GMD/EMP.

Resilience to Aircraft Impact: The NuScale power plant reactor building is able to withstand aircraft impact as specified by the U.S. Nuclear Regulatory Commission (NRC) aircraft impact rule.

Cybersecurity: Module and plant protection systems are non-microprocessor based using field programmable gate arrays that do not use software and are therefore not vulnerable to internet cyber-attacks.

These resilience features are bolstered by NuScale’s Triple Crown for Nuclear Safety™, which means that even upon loss of grid power, no operator or computer actions, AC or DC power, or additional water is needed to keep the reactors safe—a first for commercial nuclear power that provides an unlimited coping period. Our plant design incorporates several simple, redundant, and independent safety features offering unparalleled system resilience, which we continue to improve upon. To learn more about the level of resilience that the NuScale plant offers, visit our Built for Resilience page.