World's most advanced nuclear reactor is now under construction

Bill Gates leads the way yet again. Cleaner, safer, cheaper energy, here we come!

Bill Gates (center) breaking ground on the world’s first operational Natrium plant

Most reasonable plans to decarbonize the world’s power generation advocate for all types of renewable energy, each used where it’s most appropriate: solar, wind, hydro, and nuclear. Advocacy for nuclear has long been hampered by the fact that all reactors currently operating are of desperately antiquated designs, and the general public’s lack of understanding of the fact that the designs currently being developed have almost nothing in common with them. The well-known nuclear accidents such as Three Mile Island, Chernobyl, and Fukushima would not be possible with Generation IV reactors (of which there are a number of different designs).

But that hasn’t stopped leading advocates from continuing their charge. Most attention in the “next gen reactor enthusiast community” has been focused on Liquid Fluoride Thorium Reactors (LFTRs), and even I have raved about these. They’re great.

Bill Gates, however, was looking at a different model, one that is much less well known. It’s called the Traveling Wave Reactor (TWR), which is a very different kind of design. Gates founded a company called TerraPower in 2008 to actually build an operational TWR in Kemmerer, Wyoming. They broke ground this week. It is on track to begin operations by 2030.

TerraPower’s partners include the US Department of Energy, Los Alamos National Laboratory, Lawrence Livermore National Laboratory, ITER (which is interestingly a fusion project), and tons of investors including Warren Buffett’s Berkshire Hathaway.

The TWR is an interesting design. You only fuel it once, and then it runs for decades — 30 to 60 years. It’s loaded with fertile material that is cheap and widely available: depleted uranium (think of existing old-school nuclear waste) and/or natural uranium. The “traveling wave” concept refers to the progress of the reaction through the fertile material: converting it to fissile Pu-239, and burning it up in situ. It takes those long decades for the fission reaction “wave” to progress all the way through the core. At the end of those decades, what’s left is waste which is far, far less than you would have had from a conventional nuclear reactor, lower level, safer, and much of it will have industrial applications.

It is a closed system. That means that during the core’s operational lifetime, nothing goes in and nothing comes out except heat. There is nothing to break or go wrong. The slow progress of the reaction is immune from going “out of control” or melting down. In many ways it is a lot simpler than a LFTR.

TerraPower’s plant is called Natrium — an obsolete name for sodium. This is because the Natrium plant pairs the TWR with a great heat storage reservoir of liquid sodium (which is separate from the TWR and never radioactive). Since the TWR puts out a constant amount of heat but the grid’s power needs change throughout the day, Natrium uses the liquid sodium heat storage as a sort of battery, sending as much of it as is needed to the steam turbines to generate electricity.

When completed and operational, the Kemmerer plant will produce 345 megawatts of power, enough for a quarter of a million households — think of a city the size of Orlando, Florida... 100% carbon free.

It’s important not to confuse this with other systems, like fusion reactors (which have been a decade away for nearly a century and remain largely speculative), cold fusion (pseudoscience as far as we know), and other older reactor designs. It’s really its own thing and deserves to be known for its own merits and not for the failings of other technologies.

Here is a great page on the TerraPower website to learn more.

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