Triple Crown for Nuclear Plant Safety

Setting New Standards for Safety

The NuScale plant, with its innovative design, has created the new standard for rigorously proven safety through the Triple Crown for Nuclear Plant Safety: to safely shut down and self-cool, indefinitely, with:

  • No operator or computer action
  • No AC or DC power
  • No additional water

NuScale plant does not require DC batteries to place the plant in a safe cool-down condition following an extreme event. This breakthrough eliminates the need for safety related DC batteries usually needed to align valves and to power systems needed to provide cooling of the nuclear core. Safety valves align in their safest configuration on loss of all plant power.

Commercial nuclear power plants use large banks of DC batteries as backup power for their Engineered Safety Feature Actuation Systems (ESFAS). Because these batteries serve a safety function, they are classified as a “1E system.” One of the key functions of the ESFAS is to start the emergency core cooling system (ECCS).

With NuScale design’s simplicity, only a handful of safety valves need to be opened in the event of an accident to ensure actuation of the ECCS. These safety valves have been mechanically pre-set to align to their safe condition, without the use of batteries, following a loss of all station power. No AC or DC power is required for this valve alignment.

Similarly, no pumps or additional water are required to provide core cooling for an indefinite period of time. The only safety-related DC batteries needed for a NuScale plant are for post-accident monitoring of system conditions.

NuScale Power’s complete alternate power system concept eliminates the need for safety grade DC power to accomplish ESFAS functions for shutdown and core cooling. The non-provisional patent was filed in March 2013. NuScale submitted a topical report to the U.S. Nuclear Regulatory Commission, which was accepted for review in January 2016, and in January 2018, the U.S. Nuclear Regulatory Commission concluded that NuScale Power’s novel safety design approach eliminates the need for class 1E power for its small modular reactor (SMR).