Building a Safer, Cleaner Nuclear Reactor

I had an opportunity to read a copy of Popular Science while waiting for a doctor appointment, and I had forgotten how much I had liked that magazine as a young adult. There were several interesting articles, but the one titled “Revive the Nuclear Dream” was fascinating. Two young scientists, Leslie Dewan and Mark Massie, have been working on nuclear power generation since they found articles about reactor research performed at Oak Ridge at an MIT library in 2009. One subject was molten salt reactors, and it intrigued them that using liquid uranium fuel instead of solid fuel eliminates the chance of a meltdown. “So they dusted off the Oak Ridge design and got to work. Today, their start-up, Transatomic Power, is poised to build a new, even better molten salt reactor.”

The idea has some very compelling possibilities. Fuel rods from light water reactors, the design used at existing U.S. nuclear power plants, have to be replaced when only four percent of the uranium has been converted to energy. The molten salt reactor will convert 96 percent of the uranium into energy and generates 75 times the amount of electricity per ton of uranium. Of course another advantage is there is less waste to manage. Even better is that their reactor could run on spent fuel from those other reactors.

The article describes how the reactor works. Uranium salt is liquefied by heating it to 500 degrees C, and the molten salt is pumped past zirconium hydride to slow down the neutrons and induce fission. The krypton and xenon that poisons light water reactor fuel rods is continuously off-gassed. “You basically simmer the reactor like a Crock-Pot for decades…The fuel salt flows through a loop with a drain that is blocked by a freezer plug, a chunk of electrically cooled frozen salt. If the reactor loses electricity, the plug melts, and the fuel drains into a tank where it cools and solidifies.” That feature makes the design “virtually accident proof.”

The big hurdle for the technology is that the Nuclear Regulatory Commission doesn’t have a framework for licensing “advanced reactors.” The coal and natural gas lobbies see nuclear as a threat and some environmental groups will fight anything labeled “nuclear.” The two young scientists want a regulatory pathway developed, but good luck with that. We may still be developing smart and ambitious entrepreneurs, but we haven’t found a way to make government bureaucracies lobby-proof, efficient, or courageous. China would probably welcome the technology, but Dewan says they want to succeed in the U.S. I think we should think of ways to help them. My first contribution is this commentary.  Meet the two impressive people by watching the video on the home page of their web site.

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