The Babcock & Wilcox Company (B&W) and TerraPower have signed a Memorandum of Understanding (MOU) to support the development of TerraPower’s Generation IV traveling wave reactor (TWR). Unlike B&W’s Generation III++ small modular reactor (SMR) mPower which is based on PWR technology and standard fuel enriched to 5% (earlier post), TerraPower’s TWR is a larger reactor based on Generation IV technology and designed to use depleted uranium as fuel.
Nuclear fission power plants produce electricity by utilizing the heat resulting from splitting large atoms, such as U-235, into smaller atoms. Each time an atom splits (or “fissions”) it releases neutrons and heat. In turn, released neutrons cause other fissions, creating a sustained chain reaction.
TWRs, also known as a breed-and-burn reactors or nuclear-burning-wave reactors, are a variety of fast reactor that uses an initial mass of low-enriched fuel to initiate a wave of fission that can then continue propagating through fertile fuel, such as natural or depleted uranium.
As described in a 2012 paper by TerraPower staff, the TWR is of the “standing wave” type, meaning that assemblies are shuffled to keep the power producing region in one place.
The TWR commercial reactor plant design is a 1,150 MW liquid-sodium-cooled fast reactor that uses depleted uranium as fuel. The novel design allows for the use of depleted uranium generated by the enrichment process used for existing light water reactors fueled with enriched uranium.
|Source: TerraPower. Click to enlarge.|
The TWR’s economic benefits stem from its ability to breed and burn metallic fuel comprising initial starter fuel of U-235 and U-238. Conventional nuclear energy plants use U-235 because U-238 is considered too weak of an energy source.
TerraPower’s ability to develop new fuels and materials that can breed and burn U-238 could enable a TWR to get up to 50 times more energy out of every pound of mined uranium than can a conventional light water reactor, the company says.
With the conceptual design phase under way, B&W will provide support to TerraPower as the project enters the preliminary design phase.
B&W will provide TerraPower with services and program support in multiple areas, which may include design and fabrication of engineered components; fuel fabrication process development, prototype fabrication, fuel services; reactor design engineering; reactor operations support; staff augmentation, both US and foreign assignment; engineering services; flow loop testing; licensing support; and materials testing.
Through this MOU and the agreement on which the parties are currently working, B&W will be recognized as a strategic technology supplier, while TerraPower continues its design work and prepares to commercialize the reactor globally.
R. Petroski, J. Cheatham, et.al. (2012) “Traveling Wave Reactor Core Design Using Massively Parallel Precomputation,” Trans. Am. Nucl. Soc. 106, 830-833
K. Weaver et al. (2009) “Extending the Nuclear Fuel Cycle with Traveling-Wave Reactors,” Proc. Global 2009, Paris, France, September 6-11, 2009, No. 9294