In mid-October, the Department of Energy selected TerraPower to demonstrate the Natrium™ reactor and energy system with its technology co-developer GE Hitachi Nuclear Energy. An innovative and cutting-edge aspect of this technology is the inclusion of a molten salt energy storage system. It builds on the technology used in solar thermal generation and has 10 times more storage capacity than the biggest lithium ion battery storage project in the world today.

In fact, TerraPower recently joined the Energy Storage Association as part of efforts to share information related to energy storage development and innovation.

What is the Natrium reactor and energy system?

The Natrium technology uses a sodium fast reactor to produce heat, which can be used to generate electricity immediately or be contained in thermal storage reserves for hours. This unique combination with energy storage allows the reactor to operate at a steady state, supporting the increased use of renewables and helping utilities capture more daily electricity revenue. As more renewables are integrated into the grid, the demand for gigawatt-hour-scale energy storage will continue to increase.

How does the Natrium energy storage system work?

The sodium fast reactor will run at 100% power, 24 hours a day, seven days a week. However, when power demand is low, the heat produced by the reactor will be stored in the molten salt tanks. That stored heat can be turned into electricity upon demand from the grid when need peaks or wind and solar sources are unavailable. When demand is high, the turbines will ramp up to produce up to 150% of the nominal reactor power.

How does the Natrium technology’s energy storage system build on those used in solar thermal generation?

Molten salt storage has been used in the solar industry since 2008 at the Andasol 1 plant. Approximately 180 such plants have been built around the world and companies have had success when combining molten salt storage with parabolic trough solar plants.

There are numerous technical developments that enable a nuclear reactor to charge the molten salt energy storage system. The Natrium technology leverages the equipment and system design from solar thermal facilities in the U.S. and around the world, and applies the best practices and lessons learned to its own unique application. 

Notably, the Natrium technology’s application of molten salt storage is far less demanding in terms of the frequency and magnitude of temperature variations compared to solar applications. This is because the heat source is the reactor, which produces heat at a constant level, 24 hours a day, seven days a week.

Learn more about the Natrium technology and how it will provide flexible clean energy at a competitive cost.