Pre-set valves play a key role in NuScale Power’s recently announced technological breakthrough whereby its module does not require any electrical power to be able to achieve safe cooldown should the need arise. Additionally, NuScale’s technology does not require any on-going operator action or additional water to achieve safe cooldown.

The events of earthquake and tsunami-stricken Fukushima highlighted the importance that traditional reactors have of needing back-up sources of electricity to power the essential valves and pumps needed for long-term cooling to their nuclear power plants.

Dr Jose Reyes, NuScale’s co-founder and chief technology officer, announced at the Nuclear Energy Insider SMR Conference in Columbia, SC (US) that NuScale is introducing a safety system that does not require DC batteries to place the plant in a safe cool-down condition following an extreme event. “This is a revolutionary solution to one of the biggest technical challenges for the current fleet of nuclear energy facilities. Because of our unique design, it allows the NuScale plant to achieve a ‘Triple Crown’ for nuclear plant safety—to safely shut down and self-cool, indefinitely, with no operator action, no AC or DC Power and no additional water.” The patent-pending breakthrough eliminates all of the DC batteries usually needed to align valves and to power systems needed to provide cooling of the nuclear core.

All commercial nuclear power plants currently use large banks of DC batteries as backup power for their Engineered Safety Feature Actuation Systems (ESFAS). Because of the simplicity of the NuScale design, 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. The only safety related DC batteries that will be needed for a NuScale plant would be for the purpose of post-accident monitoring of system conditions.