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| Fig. 1: Bill Gates speaking about the nuclear future. (Source: Wikimedia Commons) |
Terrapower is a startup company founded in 2006 by Microsoft's Bill Gates (Fig. 1) that is looking to solve the current and future world energy crisis through advancements in technology and innovation in nuclear energy. More specifically, they are a nuclear reactor design company that is developing a class of nuclear fast reactors called the traveling wave reactor. Terrapower is a leading nuclear innovation company that strives to improve the world through nuclear energy and science. [1] In most recent news, Bill Gates proposed a plan to the United States government that would solve all of the problems that nuclear reactors typically have i.e. on the environment. He proposed a plan where he would pledge $1 billion of his own money alongside $1 billion of privately raised capital to accompany federal funding to help fund a pilot of his company's never-before-used technology. [1] Gates claims that nuclear energy is the future of the United States because it is the only energy that is carbon-free and available 24/7. However, many experts believe that the technology is something that is flawed and likely to be a failure.
The technology that Terrapower is attempting to develop is called a traveling wave reactors, or TWR. A TWR is a class of reactor that is uniquely designed to operate indefinitely after a startup period using only natural or depleted uranium. [2] The advantage that the TWR has over traditional nuclear reactor designs is that it could have the potential to have a very long core life of nearly 60 years. Designs for commercial TWRs have net power ratings ranging from 600 MW to 1200 MW electric. This range of power levels permits a gradual evolution from the first 600 MW electric prototype plant to larger units that achieve improved economies of scale. Core inlet and outlet temperatures are 360°C and 510&*deg;C, respectively, corresponding to a plant net efficiency of approximately 41%, a significant improvement over the ~33% efficiencies typical of current commercial Light Wave Reactors (LWRs), which is the typical reactor being used today. [3] Furthermore, this lengthened core life allows for nearly 30 times greater fuel utilization than typical reactors. Additionally, because the TWR uses depleted uranium this allows for an easy expansion and implementation of new TWR's in new places because it can use the discharged fuel from the previous TWR's that are already in use. Bottom line, the TWR that Terrapower is attempting to design is more efficient and easier to reproduce and expand than typical LWRs.
As with any startup, there are bound to be challenges faced in the early years of developmentand such is the case for Terrapower. There are four major challenges that Terrapower faces. First, there is the positive coolant temperature coefficient challenge. Because the TWR has such a large active core volume they need to find a way to minimize the neutron leakage because current designs are not feasible because of the depleted uranium core. [2] Second, there is a high peak discharge burnup challenge. Burnup is a measure of how much energy is extracted from a primary nuclear fuel source. Basically, the reactor has a minimum requirement of burnup for operation, but the challenge with meeting this minimum requirement is that minimum requirement is very high and there is a very narrow window in which the burnup can sit. The challenge will be keeping the burnup within the window while still allowing for variability. [2] Third, there is the high cladding and duct fluence challenge. Fluence is defined as a stream of particles crossing a unit area, and the major problem with the TWR is that the fluence with current TWRs is three times greater than what has already been developed. [2] Lastly, there is the overall design challenge of getting everything to work and fit symbiotically. [4] Another challenge, perhaps the hardest one, is getting both sides of the political arena to agree to fund the technology.
Terrapower is a startup company that is looking to make the world a better place. They are attempting to innovate a technology to help fight global warming and although the road ahead of them is long and challenging, it looks promising. Gates is also very passionate about this project and is pledging billions of dollars to its development. The promising upside to this technology is that if the first reactor is successful, it can easily be expanded across the globe in a matter of a few years, giving a sustainable energy option to countries all over the world.
© Brandon Wulff. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] D. Grossman, "Bill Gates's Experimental Nuclear Power Plant Halts Construction in China," Popular Mechanics, 2 Jan 19.
[2] P. Hejzlar et al., "Terrapower, LLC Traveling Wave Reactor Development Program Overview," Nucl. Eng. Technol. 45, 731 (2013).
[3] J. Gilleland, R. Petroski, and K. Weaver, "The Traveling Wave Reactor: Design and Development," Engineering 2, 88 (2016).
[4] M. Cohen, M. Werner, and C. Johns, "Mechanical Model of a Terrapower, Traveling Wave Reactor Fuel Assembly Duct," Terrapower LLC, 18 Aug 13.
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