Bill Gates stops chasing nuclear 'wave', pursues variety of reactors

His fission company, TerraPower, alters its "traveling wave reactor," explores thorium, liquid fuel and alternative designs.

Slasher. Bill Gates believes that nuclear power can slash the world's CO2 emissions. His fission firm, TerraPower, is now investigating several reactor technologies. That's Gates with guitar hero Slash.


TerraPower, the Bill Gates-chaired nuclear company, has altered the design of its so-called traveling wave reactor and has begun exploring other fission technologies as well, including thorium fuel and molten salt reactors.

The traveling wave reactor breeds fuel by burning a long cylinder of uranium that yields a "wave" of plutonium. In TerraPower's original design, the uranium would burn like a candle, with the wave moving slowly along the cylinder.

But that required a tricky engineering challenge: the reactor's cooling system had to follow the wave through the reactor. So TerraPower has redesigned the reactor so that the wave stays put, CEO John Gilleland told me in a phone interview, as I first reported on my Weinberg Foundation blog.

"It's just the practical considerations associated with making the most of every neutron, and the engineers' love of keeping the cooling system in one place, and not chasing the wave," he said.

In a fission reactor, a coolant absorbs heat from nuclear reactions and uses the heat to drive a turbine. TerraPower's coolant is liquid sodium.

Gilleland said the change "didn't set us back at all." Despite the alteration - made about two years ago - TerraPower still calls the reactor a "traveling wave" (TWR). It's working with partners in Russia, China, Japan, South Korea and the U.S. in hopes of building a prototype by 2022 and a commercial reactor by the mid-2020s. The TWR is a type of "fast reactor," a technology that Russia is pursuing vigorously and for which China has big plans. Fast reactors do not slow down - or "moderate" - neutrons the way today's "thermal reactors" do.

At the same time, TerraPower has quietly begun exploring alternative nuclear technologies , including thorium fuel and "high temperature reactors" such as molten salt reactors (MSRs) and others. Each of the alternatives offers a different set of advantages, including improved safety, reduced waste, less risk of weapons proliferation, and improved operating efficiencies. High temperature reactors can also serve as clean sources of industrial heat .

“We are an innovation house, so we like to look at other approaches,” Gilleland said. “Our big bet is on the traveling wave reactor because it fulfills so many of the goals that we would like to see nuclear achieve. But we’re always looking for innovations that lead to better safety or minimization of waste and so forth and so we have several things going there. Although those activities are small, that’s the way large activities get started.”

Gilleland described the innovation initiative as a framework to facilitate new ideas that could lead to a project.

“It’s like Google and other places – the best ideas sometimes came from the person doing the backstroke in the swimming pool, or at home thinking,” said Gilleland. “So we want to just make sure that people have a certain fraction of their time for free thinking.”

The company has hired Jeff Latkowski as director of innovation. Latkowski is a former chief scientist for commercialization at the National Ignition Facility fusion project at Lawrence Livermore National Laboratory. "My job at TerraPower is everything outside the traveling wave reactor," Latkowski told me after we attended the same Thorium Energy Alliance Conference in Chicago last month.

TerraPower is not developing fusion. For more on what it's doing, see my Weinberg blog.

Photo of Bill Gates and Slash at the 2008 Consumer Electronics Show is a screen grab from a YouTube video posted by Daniel Espelid Pedersen.

NOTE: Story updated around 10:10 a.m. PDT adding that TerraPower made the change from "traveling" to "standing" wave about two years ago. (Will they ever change its name to reflect the design alteration?).

Some fast links to more nuclear stories, on SmartPlanet:

You can find a rich archive of alternative nuclear stories here, including thorium, molten salt, pebble beds, fast reactors, modular reactors, fusion and more.

This post was originally published on


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