How NuScale Technology Works

Each NuScale Power Module™ is a self-contained module that operates independently of the other modules in a multi-module configuration. However, all modules are managed from a single control room.

The reactor (1) measures 65 feet tall x 9 feet in diameter. It sits within a containment vessel (2). The reactor and containment vessel operate inside a water-filled pool that is built below grade. The reactor operates using the principles of natural circulation; hence, no pumps are needed to circulate water through the reactor. Instead, the system uses a convection process. Water is heated as it passes over the core (3). As it heats up, the water rises within the interior of the vessel. Once the heated water reaches the top of the riser (4), it is drawn downward by water that is cooled passing through the steam generators. The cooler water has a higher density. It is pulled by gravity back down to the bottom of the reactor where it is again drawn over the core. Water in the reactor system is kept separate from the water in the steam generator system to prevent contamination. As the hot water in the reactor system passes over the hundreds of tubes in the steam generator, heat is transferred through the tube walls and the water in the tubes turns to steam. The steam turns turbines which are attached by a single shaft to the electrical generator. After passing through the turbines, the steam loses its energy. It is cooled back into liquid form in the condenser then pumped by the feed water pump back to the steam generator where it begins the cycle again.

NuScale Power Module details include:

  • Thermal capacity – 160 MWt
  • Electrical capacity – > 50 MWe (gross)
  • Capacity factor – >95 percent
  • Dimensions – 76' x 15' cylindrical containment vessel module containing reactor and steam generator
  • Weight – ~ 700 tons as shipped from fabrication shop
  • Transportation – Barge, truck or train
  • Cost – Numerous advantages due to simplicity, off-the-shelf standard items, modular design, shorter construction times, <$5,000/KW
  • Fuel – Standard LWR fuel in 17 x 17 configuration, each assembly 2 meters (~ 6 ft) in length; 24-month refueling cycle with fuel enriched less than 4.95 percent

Read more about the benefits of NuScale's small modular reactor.
NuScale Power System Operation
Reactor Diagram
NuScale Reactor Diagram