You might get the idea from reading my blog that I have something against thorium. It ain’t so! I consider thorium a very promising candidate for supplying our future energy needs. It’s just that there’s something about the stuff that seems to drive people off the deep end. I actually missed the really bad thorium idea that’s the subject of this post when it turned up on the Internet about a year ago. However, the articles are still out there, and are interesting examples of how really bad science can be promoted as perfectly plausible by people who have impressive credentials, but actually don’t know what they’re talking about.
The idea in question was the use of thorium fueled mini-subcritical reactors to generate power for a new generation of electric cars. It was proposed by an outfit called Laser Power Systems (LPS). Science may not be their strong suit, but their PR people must be top drawer. They actually convinced the people at Cadillac to embarrass themselves by designing a “concept car” around the idea.
Steven Ashley penned an article for GE’s Txchnologist website about the idea entitled, “Thorium lasers: the perfectly plausible idea for nuclear cars.” Ashley, who is described as a contributing editor for Scientific American and whose work has appeared in such venues as Popular Mechanics, MIT’s Technology Review, and Physics Today, does not explain on what credentials or academic background he bases his conclusion that the idea is “perfectly plausible.” Presumably, none, because it isn’t. He tells us, quoting an LPS official, that they are “working on a turbine/electric generator system that is powered by ‘an accelerator-driven thorium-based laser.'” The same individual further assured him that the new technology “would be totally emissions-free, with no need for recharging.” Ashley adds that,
…because a gram of thorium has the equivalent potential energy content of 7,500 gallons of gasoline, LPS calculates that using just 8 grams of thorium in the unit could power an average car for 5,000 hours, or about 300,000 miles of normal driving.
Where, the interested reader might ask, is all this energy to come from? Lasers, after all, are not a source of energy. In general, they are rather inefficient energy sinks. I found several similar articles, and none of them ever gets around to explaining this intriguing mystery. Well, the only possible way that such a small amount of thorium could come close to producing that much energy is via fission, and even if every bit of it underwent fission, it would still produce about an order of magnitude less energy than 7,500 gallons of gasoline. We are assured that, “only a thin layer of aluminum foil is needed to shield people from the weakly emitting metal.” True, but the same doesn’t apply to thorium’s fission products. They would eventually accumulate to become a potentially deadly source of radiation unless heavily shielded. None of the articles ever gets around to explaining where, exactly, the “thorium laser” comes in, what specific atomic transitions it would rely on, how, exactly, it would be pumped, and similar seemingly obvious questions.
What can one do but shake one’s head and congratulate the LPS people on their brilliant success in bamboozling Cadillac and a whole host of ostensibly perfectly respectable science writers into taking seriously an idea that is completely wacky on the face of it? I’m certainly glad that I don’t fall for such pseudo-scientific nonsense. Oh, by the way, would anyone out there like to purchase a slightly used supply of fish oil pills?