Veni Quid Veniat

     The advantages of a thorium-fueled reactor seem almost too good to be true. Thorium is approximately four times as abundant as uranium, a much higher percentage of the energy inherent in that supply can be extracted, and it is often found in conjunction with, and can easily be separated from, the vitally important rare earth elements, making it an attractive long-term option. In an age when the dangers of nuclear proliferation are glaringly obvious, one feature of thorium which to Admiral Rickover was a negative, has become one of its most highly touted selling points: a liquid fluoride thorium reactor (LFTR) of the sort proposed by most of the thorium lobby does not produce weaponizable byproducts (Hargraves and Moir 2010). An LFTR produces energy, freshwater, and a very small amount of low-grade waste. Due to this fact it could be installed in places a conventional uranium reactor could not, removing the opportunity for endless foreign policy debates about whether a particular partially unhinged petty dictator is pursuing nuclear power for peaceful or military reasons.

     Thorium's case is further advanced by the nature and amount of the waste produced. An LFTR produces less than 10% of the waste a conventional reactor does, and waste from an LFTR has less than 1% of the radiotoxicity of waste from a conventional nuclear reactor. Further, that waste, rather than taking on the order of ten thousand years to become safe, it requires closer to one hundred years to become safe. These advantages are due to the fact that most of the waste produced by an LFTR is reused in the reactor, leaving only a small, relatively innocuous portion to be disposed of.

     Once an LFTR has been built, thorium can also be more than competitive economically. At present electricity in the United States costs between $0.05 and $0.06 per kWh and the potential “clean” energy sources—wind and solar—cost between $0.20 and $0.30 per kWh. In contrast, an LFTR has the potential to produce power at a cost as low as $0.03 per kWh (Hargraves and Moir 2010). The difference per kWh is small, but when one considers that, given that the average home consumes around 10,000 kWh per year, an LFTR could mean the difference between an annual electric bill of $50,000 or $60,000 at current rates and a bill of only $30,000 it suddenly becomes much more meaningful.

     In light of the devastating effects of mismanaged nuclear power at Chernobyl, Three Mile Island, and, more recently, Fukushima, few care about the logistics and viability of a power source if it also carries the potential to irradiate the surrounding countryside. Here thorium continues to shine. A conventional reactor is cooled by pressurized water, creating the potential for a catastrophic leak. Further, when the temperature in a conventional reactor rises the fuel expands, which accelerates the reaction, which heats the reactor, which in turn causes the fuel to expand. A conventional reactor aslo requires active cooling, meaning that if power is shut down such that cooling can no longer take place, as occurred at Fukushima, the reaction will continue to accelerate until the reactor melts down. An LFTR is cooled molten fluoride salt which is not under pressure, removing the single most dangerous feature of conventional reactors. Additionally, an LFTR will simply shut down if power is removed—unlike a conventional reactor, it does not require power to shut down but to stay running (Hargraves and Moir 2010; Shiga 2011). The LFTR thus presents an extremely attractive option as far as safety is concerned.

     Thorium presents an economical, safe, effective, and “clean” energy source. It can compete with and beat coal and oil in cost. It can be used in areas too unstable to sustain conventional nuclear and too poor or incompetent to use other conventional fuel sources. It's waste products are not abundant and are relatively innocuous. Although mining and transportation may be accompanied by some pollutant emissions, the reactor itself is not. Why, then, is thorium still an unknown cousin of uranium? The answer, as one might expect, is money and government. A prototype thorium reactor would cost on the order of $1 billion dollars; a commercial model closer to $5 to $10 billion. Very few people are willing to spend that kind of money on a project which is, whatever its potential, still unproven. Further, any investment of that magnitude would have yield a significant return within a reasonable amount of time. At best, it would take 10 years for an investor to being to see returns on the investment and, crucially, the extent and even the existence of those returns hinges on an uncertain regulatory environment. In countries where the government has demonstrated that it is willing to support investment in thorium research projects to build thorium-fueled reactors have moved ahead. In countries where the government has not shown such resolve thorium research has stalled or has never begun. In any case, it is hard to believe that the obvious benefits of thorium will remain hidden for long: it seems far more likely that in thorium we can see what will one day be unequivocally the fuel of the future.



Hargraves, Robert, and Ralph Moir. 2010. "Liquid Fluoride Thorium Reactors." American Scientist 98, no. 

     4: 304-313.