September 17, 2015
TerraPower is working to develop a new type of fast reactor, the traveling wave reactor (TWR), which uses a metallic fuel form to help achieve both the safety and economic benefits inherent in its design. Because such a fuel type has not been manufactured in the United States for more than 30 years, and to make our TWR a reality, TerraPower has engaged a number of suppliers to recreate and improve the processes needed for commercial production. One important supplier, the Idaho National Laboratory (INL), is working cooperatively with us to develop the ability to use extrusion as a way to produce fuel slugs for use in the TWR.
I recently visited INL’s Materials and Fuels Complex to observe one of INL’s first metallic fuel extrusion demonstrations. Specifically, the lab staff performed a depleted uranium extrusion, a process that shapes the material by forcing it through a die. This test served to restore a metallic fuel fabrication capability that has not been used in the United States since the 1980s.
For the uranium extrusion test, I watched INL subject a cylindrical billet of depleted uranium metal to high temperature and pressure to force it through a shaped die. The process produced a thinner, longer form that will be suitable to use as fuel pins for continued experiments and testing of fuels for the TWR. This is a particularly exciting milestone because, by using an extrusion process, we have the potential to reduce both cost and waste compared to the traditional casting process that was employed for producing fuel for previous domestic fast reactors. The extrusion process also requires less follow-up work to ensure the quality and consistency of TerraPower’s final fuel product before it is encased in cladding.
INL’s unique set of facilities, capabilities and resources help demonstrate the feasibility of this key process. The U.S. Department of Energy has placed a priority on collaboration in recent years, which has enabled TerraPower’s cooperation with INL and allowed both teams to achieve more than what TerraPower or INL engineers could have accomplished single-handedly. I look forward to the continued success of both teams!