Jumpstarting Advanced Reactors

With the company’s establishment in 2008, TerraPower jump-started the timeline for advanced nuclear reactor designs and components. TerraPower has made progress by leveraging public-private partnerships, seeking excellence in commercial partners, and forging a new supply chain for fuels and materials. The company aims to achieve startup of a 600 megawatt-electric prototype traveling wave reactor (TWR) in the mid-2020s.

Achievements to Date

  • Determined a path forward for preliminary and final design, licensing and supply chain in order to minimize delays in bringing the initial plant to completion;
  • Established working relationships with a range of private companies and national labs to support design activities; and
  • Began to conduct ongoing experiments to test innovative material and fuel designs.


Phase one simulator
TerraPower’s first phase system-level simulator

TerraPower completed the core concept design for the prototype TWR and defined key equipment and system parameters. The company continues to refine design details and push forward with the commercial TWR plant concept design.

Pairing cutting-edge computing power with real-world data, TerraPower continues to improve the TWR design using advanced simulations. TerraPower is analyzing the design using new seismic, physics and mechanical methodologies.

In addition, the company completed constructing and programming a steady-state model of the first phase system-level simulator for the TWR, a step that puts engineers in the control room of a virtual TWR to study of the reactor’s operation from start-up to full power.


Samples of HT-9, an advanced steel alloy for use in the TWR
Samples of HT-9, an advanced steel alloy for use in the TWR

Working with a variety of partners around the world, TerraPower is establishing a commercial supply of the advanced steel alloy, HT9, for use in the TWR’s fuel cladding and ducts.

Over the past several years, the company has conducted extensive research and development to optimize the chemistry and fabrication process for this type of steel. This effort has involved varied organizations such as Idaho National Laboratory, Japan’s Kobe Steel, the University of Michigan’s Ion Beam Laboratory, and U.S.-based metal fabricators Carpenter Steel and Veridiam.

Thanks to these collaborations, TerraPower has procured a supply of HT9 and is now manufacturing ducts and cladding materials for the prototype TWR.


Working with AREVA, TerraPower has built the largest fast reactor fuel assembly ever built.
TerraPower’s first full-size fuel assembly

TerraPower is restarting U.S.-based development of fast reactor fuel in preparation for the prototype TWR. Working with Idaho National Laboratory, TerraPower commissioned a lab-scale fuel fabrication facility,which is on track to produce the first extrusions of metallic nuclear fuel in the U.S. since the 1980’s. Currently, fuels are also being tested in the Advanced Test Reactor at Idaho National Laboratory.

In partnership with AREVA Federal Services, TerraPower manufactured the first full-size test assembly for the TWR. Additionally, the company is now receiving and analyzing results from its first irradiation experiments, conducted in partnership with the BOR-60 fast reactor in Russia. Along with a large number of U.S. universities, TerraPower finds value in this unique facility for fuel sample testing and fuel test simulations.