A NEW WAY?
Depleted Uranium as Fuel Cuts Path to Less Waste
TerraPower's traveling wave reactor (TWR) will offer a path to zero-emission, proliferation-resistant energy that produces significantly smaller amounts of nuclear waste than conventional nuclear reactors. After an initial start-up with a small amount of low-enriched material, this innovative reactor design can run for decades on depleted uranium – currently a waste byproduct of the enrichment process. An established fleet of TWRs could operate without enrichment or reprocessing for millennia. TerraPower has explored the advanced physics of this concept in detail with 21st-century computational tools and is moving forward with the overall plant design.
Huge amounts of depleted uranium, useless to today's reactors, already exist in stockpiles around the world. Stocks of this material grow as uranium is enriched for the refueling of conventional reactors. The TWR directly converts depleted uranium to usable fuel as it operates. As a result, this inexpensive but energy-rich fuel source could provide a global electricity supply that is, for all practical purposes, inexhaustible.
There are currently 700,000 metric tons of this low-level nuclear leftover product in the United States. Using a TWR, an 8-metric-ton canister of depleted uranium could generate 25 million megawatt-hours of electricity – enough to power 2.5 million U.S. households for one year.
The traveling wave reactor uses the simplest nuclear energy fuel cycle – a once-through cycle. The reactor converts fissile material to its own nuclear fuel where it needs it, when it needs it. Once a wave is started with enriched material, a traveling wave reactor never needs fissile material and will continue producing power as long as depleted uranium is supplied. This means more stable and sustainable nuclear power than exists today.
A TWR can sustain a fission chain reaction given only non-fissile fuel such as depleted uranium because it sets up a slow-moving wave in which neutrons produced by fission reactions in the power-producing region convert adjacent fuel from fertile isotopes (such as U-238) into fissile isotopes (such as Pu-239).
In this video, TerraPower CEO John Gilleland gives a basic explanation of the traveling wave reactor (TWR) technology and how the TWR turns depleted uranium into fuel.