Protection against Extreme Events

NuScale's SMR is designed to protect the public, workers, and the environment if an extreme event occurs. For example:

  • Integral reactor design eliminates interfacing pipes and pumps that could potentially fail, eliminating accidents that are traditionally very challenging, such as a large break LOCA (Loss of Coolant Accident)
  • Vacuum inside containment provides significant unique safety advantages in the event of a severe accident
  • Large reactor pool, in which the modules are submerged, provides assured access to ultimate heat sink and radiation shielding under all conditions
  • Passive safety systems provide stable long-term cooling without a need for electrical power or makeup water
  • Complete station blackout protection
  • Operation of all passive safety systems without pumps, AC or DC power, or addition of water
  • Passive cooling of reactor for 30 days with water followed by an unlimited period of air cooling
  • Underground installation provides additional safety and security
  • No Design Basis Accident can cause core to uncover
  • Smaller source term per reactor and longer time periods of potential release.
  • Low CDF below 10-7 per module year
  • Seven Layers of Defense (Three or four more than conventional reactors)
  • Deeply embedded spent fuel pool with 4 times the water volume per MWt of conventional nuclear reactors


Possibility of Core Damage Significantly Reduced
The safety of the plant is enhanced due to a number of key features, such as a simplified design, inherent cooling capabilities, passive engineered safety features, and lower core power density. In the extremely unlikely event that a NuScale core is damaged, consequences would be well below the threshold to warrant off-site evacuations.
Integral Reactor Design Eliminates Traditional Accidents
Core Damage Frequency Significantly Reduced (click to expand)
NuScale and the Future of Nuclear Energy
How NuScale Measures Up to the NRC's Goals (click to expand)