Nuclear power is back!

Usually, discussions of decarbonizing energy production involve solar, wind, tidal and geothermal. But nuclear power generation doesn’t generate greenhouse gas (though the large amount of concrete in nuclear power plants does). Nuclear power generation has gotten a bad name with Three Mile Island, Chernobyl and Fukushima, and the waste products from nuclear power and decommissioning nuclear reactors need to be stored for millions of years before they decay to safe levels.

While there is debate about whether the famous nuclear power reactor accidents to date have really endangered many lives, there’s no doubt that solid fuel light water nuclear power reactors have an image problem. Fortunately, there’s an alternative to current nuclear power reactor design on the shelf, pioneered in the 1960s in Oak Ridge: molten salt reactors. There are a number of advantages to molten salt reactors over conventional solid fuel light water reactors:

Fission products can be removed or added while the plant is operational. Allows for removal of neutron absorbing materials that are produced during fission and for on-line refueling.

Fuel fabrication is limited to chemical processes, rather than the need to manufacture fuel rods, assemblies, tubes, etc.

High temperatures increase efficiency of heat transfer, and low pressures make for safer operation and reduce the size and costs of the reactor building.

Improved safety features such as a drain tank mechanism where the fuel can be passively cooled in the event of overheating, lower pressures and negative temperature coefficient of reactivity meaning if the temperature increases the fuel expands and becomes less radioactive.

So why were molten salt reactors abandoned in favor of solid fuel reactors? Partly because of political pressure (I’m looking at you, Adm. Rickover), and partly because of concerns over corrosion and possible tritium release.

Molten salt reactor technology has been making a comeback in the past decade, and now Bill Gates has fueled the first major commercial investment. Gates’ company TerraPower has announced the siting of a 345 MW demonstration plant in Kemmerer WY. The fuel is sodium-based, which should mitigate the tritium release risk, and the cooling system is internally powered, so not vulnerable to external power loss like what caused the Fukushima failure.

The cost of solar and wind power is declining. If the TerraPower pilot in Wyoming is successful, it should reduce the cost of nuclear power generation, and also address the intermittency issues of solar and wind. It is expected to complement, not displace solar and wind power generation.

So while fusion power is always a decade away, fission power may be experiencing a renaissance now.

https://www.cnbc.com/2021/11/17/bill-gates-terrapower-builds-its-first-nuclear-reactor-in-a-coal-town.html