Molten-Salt reactor running on ThoriumJune 2011’s Popular Science covers our future in energy (as they are wont to do) with a series of articles on various energy systems that might power our future. In the first part of the article on nuclear power, PS does a good job of describing the next generations of traditional nuclear plants, Generation IV, and how they will be more meltdown-proof than their predecessors (although they don’t even try to explain where all the radioactive waste is going to go).

However, the second part of the same article describes another type of nuclear reactor, a Molten Salt Reactor (MSR), powered by thorium instead of uranium, and goes on to list its plusses compared to traditional uranium-powered plants.  (For details, see the article.)  In a nutshell:

  • MSR is a tested design, actually built and run for 22,000 hours without a problem in 1965-69;
  • MSR reactors use very simple means to shut down the reaction in the event of a problem, making it more meltdown-proof than any other existing reactor design;
  • Thorium is four times as abundant as uranium and is easier to mine, in part because of its lower radioactivity;
  • One pound of thorium produces as much power as 300 pounds of uranium–or 3.5 million pounds of coal;
  • Thorium is 99% burned in a nuclear reaction, compared to 3% of uranium, creating significantly less waste;
  • Thorium is not fissionable after use in a reactor, making it useless for weapons;
  • Thorium waste radioactivity lasts a few hundred years, versus uranium’s tens of thousands of years.

Which begs the question: Why aren’t we switching to thorium plants?  Are we insane?

The PS article suggests that, because no actual MSR power plants are actually running, the U.S. has no regulations in place for them, and as a result, no one is likely to want to build one.  Well, everything has to start somewhere, and as thorium-run MSRs can be very small and produce power for local uses, replacing existing plants of all kinds with small local thorium-run MSRs would seem to be a smart move.  I can think of a location right off: Washington, D.C., to replace the coal-powered Capitol Power Plant that powers the Capitol building and Congress’ chambers.  If one can be placed there, and prove its worth to the federal government in daily use (not to mention easing the city’s pollution levels), it would pave the way for others nationwide.

Thorium-based MSRs, being safer in the event of catastrophe, are natural choices for areas of the world where climate or natural disasters like earthquakes threaten the operability or safety of traditional uranium-based plants.  They are designed to be a smaller reaction, and do not operate under pressure, making an explosive accident unlikely, and making containment easier.  After the recent accident at Fukushima, and past accidents at Chernobyl and Three Mile Island, the public needs to know that nuclear reactors can be made much safer than their predecessors… and MSRs are it.

And finally, the risk of waste material is significantly lessened, as less waste is generated by the plants, and remains radioactive for a much shorter time, making storage and disposal a more realistic prospect than burying uranium in facilities that must remain isolated and secure for longer than civilization has existed on Earth… by a factor of ten.

The amazing thing is, thorium-based MSRs were originally experimented with in the 1960s!  With all of the safety and security problems inherent in uranium-based traditional nuclear plants, and the desperate need for cleaner energy and a reduction of carbon pumped into the atmosphere… one can only ask: What the ever-lovin’ hell are we waiting for?