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U.S. Researcher Preparing Prototype Cars Powered by Heavy-Metal Thorium
By Keith Nuthall -

Thorium has highest
melting point of all
oxides at 3,182° F.

A U.S. company says it is getting closer to putting prototype electric cars on the road that will be powered by the heavy-metal thorium.

Thorium is a naturally occurring, slightly radioactive rare-earth element discovered in 1828 by the Swedish chemist Jons Jakob Berzelius, who named it after Thor, the Norse god of thunder. It is found in small amounts in most rocks and soils, where it is about three times more abundant than uranium.

However, the use of thorium is controversial because, as with uranium, it is used as a nuclear power source. Indeed, the internal heat of the Earth largely is attributed to the presence of thorium and uranium.

The key to the system developed by inventor Charles Stevens, CEO and chairman of Connecticut-based Laser Power Systems, is that when silvery metal thorium is heated by an external source, it becomes so dense its molecules give off considerable heat.

Small blocks of thorium generate heat surges that are configured as a thorium-based laser, Stevens tells Ward’s. These create steam from water within mini-turbines, generating electricity to drive a car.

A 250 MW unit weighing about 500 lbs. (227 kg) would be small and light enough to drop under the hood of a car, he says.

Jim Hedrick, a specialist on industrial minerals – and until last year the U.S. Geological Survey’s senior advisor on rare earths – tells Ward’s the idea is “both plausible and sensible.”

Because thorium is so dense, similar to uranium, it stores considerable potential energy: 1 gm of thorium equals the energy of 7,500 gallons (28,391 L) of gasoline Stevens says. So, using just 8 gm of thorium in a car should mean it would never need refueling.

Stevens’ prototype systems generate electricity within 30 seconds of firing a laser. This can feed power into a car, without the need for storage.

If his technology were to become successful on a commercial scale, one advantage would be that thorium is fairly common throughout the world. However, the distribution of thorium resources is poor because of relatively low-key exploration efforts arising out of insignificant demand.

The U.S. Geological Survey’s estimated thorium reserves in 2010 shows the U.S. leading with 440,900 tons (440,000 t), followed by Australia with 333,690 tons (300,000 t). However, several world organizations conclude India may possess the lion's share of the world's thorium deposits, with estimates ranging from 319,667 to 716,490 tons (290,000-1650,000 t).

Natural thorium has little radioactivity, Stevens says. What isotopes there are could be blocked by aluminum foil, so the power unit’s 3-in. (7.6-cm) thick stainless-steel box should do the trick.

“The issue is having a customized application that is purpose-made,” he says, admitting that developing a portable and usable turbine and generator is proving to be a tougher task than the laser-thorium unit.

“How do you take the laser and put these things together efficiently?” he asks rhetorically. But once that is achieved, “This car will run for a million miles. The car will wear out before the engine. There is no oil, no emissions – nothing.”

Stevens says his company should be able to place a prototype on the road within two years. The firm has 40 employees and operates out of an in-house research workshop.

Hedrick, the industrial minerals expert, says 7,500 gallons is “way more gasoline than an average person uses in a year. Switching to thorium-driven cars would make the U.S. energy self-sufficient, and carbon emissions would plummet.

“It would eliminate the major need for oil,” he says. “The main (remaining) demand would be for asphalt for roadways, natural gas, plastics and lubricants.”

Stevens’ research is part of growing efforts to develop thorium as an energy source. Scientists in India, for example, long have tried to heat thorium sufficiently to cause a self-sustaining fission reaction that can run major power plants, without the nuclear waste problems of uranium-based generators. Some North American companies are doing the same thing.

Canon Bryan, CEO of Vancouver, BC, Canada-based Thorium One, knows Stevens’ work and agrees thorium-based fuel sources are “scalable and energy efficient. There’s no reason why it should not be able to power cars.”

Thorium has unique properties that make it useful as such a source, he says. For instance, it has the highest melting point of all oxides.

So if thorium would be a safe and abundant fuel source for vehicles, other devices and even power stations, why is it not being utilized widely?

Stevens, Hedrick and Bryan all have the same answer: After World War II, a strategic decision was undertaken by industrialized nations to pursue uranium-driven energy instead, because its by-product – plutonium – could be weaponized. By contrast, it is almost impossible to make a bomb out of thorium.

However, a recent International Energy Agency report accepts there is widespread interest in thorium-power sources, with research being conducted in India, Russia, Germany, France, the Netherlands and elsewhere.

The IEA notes research from Switzerland-based physics institute CERN that proposes “the use of thorium as the feed material in accelerator-driven systems, which could serve as an energy source with minimum long-term waste production,” although this is for power generation.

But there still is skepticism in the nuclear-energy research world about using thorium as a power source, especially in mobile applications.

Reza Hashemi-Nezhad, director of the Institute of Nuclear Science at the University of Sydney, Australia, says nuclear power plants already run submarines and could operate oil tankers, “but they are not small enough to fit in the boot (trunk) of a car.”

And amid widespread concerns about terrorism, would governments allow scores of nuclear sources to roam the freeways? Processed thorium can produce uranium 233 as a byproduct. Would governments allow charging an electric vehicle using radioactive material in private garages? “Nobody will allow that to happen,” Hashemi-Nezhad says. Hedrick thinks such concerns are overblown, stressing thorium’s by-products are very hard to turn into weapons-grade material, requiring an immense amount of work and energy. Stevens agrees, emphasizing his system is “subcritical.” This means no nuclear reaction occurs within the thorium. It remains in the same state and is not turned into uranium 233, which happens only if thorium is sufficiently super-heated to generate a fission reaction. “It’s very safe,” he says.

U.S. Researcher Preparing Prototype Cars Powered by Heavy-Metal Thorium

Technical Poseur
23,313 Posts
This could play out well. Now will this have a water source that will need refilling or is it basically a scaled back nuclear reactor?

16,623 Posts
Discussion Starter #3
This could play out well. Now will this have a water source that will need refilling or is it basically a scaled back nuclear reactor?
If I'm interpreting the article correctly, it's basically a scaled-back nuclear reactor.

16,623 Posts
Discussion Starter #4
Thorium lasers: The thoroughly plausible idea for nuclear cars
by Steven Ashley - Txchnologist

Some proposed technological innovations seem so far out that they are easy to reject out of hand. But sometimes, a new idea has a kernel of plausibility. Such is the case with a new project to develop a thorium laser power generation system that its creator says could provide electricity for the grid, stand-alone power applications and even cars.

Charles Stevens, an inventor and entrepreneur, recently revealed that his Massachusetts-based R&D firm, Laser Power Systems (LPS), is working on a turbine/electric generator system that is powered by “an accelerator-driven thorium-based laser.” The thorium laser does not produce a beam of coherent light like conventional lasers, but instead merely heats up and gives off energy.

Thorium, a silvery-white metal, is a mildly radioactive element (with an atomic weight of 90) that is as abundant as lead. It is present in large quantities in India and is a much-touted stand in for uranium in nuclear reactors because its fission is not self-sustaining, a type of reaction called “sub-critical.”

The idea has energized the small but active thorium community, which holds that it is the answer to our clean energy needs because it could, effectively, power a car forever. The new technology “would be totally emissions-free,” Stevens said, “with no need for recharging.”

Laser Heating
The LPS power plant, for all its whiz-bang properties, isn’t a complete departure from traditional power generation: the thorium is lased and the resulting heat flashes a fluid and creates pressurized steam inside a closed-loop system. The steam then drives a turbine that turns an electric generator.

A 250-kilowatt unit (equivalent to about 335 horsepower) weighing about 500 pounds would be small and light enough to put under the hood of a car, Stevens claims. And 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.

Stevens isn’t the only one who believes thorium could power cars. In 2009 Cadillac introduced a thorium-powered concept car at the Chicago Auto Show. Designed by Lorus Kulesus, the sleek World Thorium Fuel Concept did not contain a working thorium-fueled nuclear-fission reactor that could generate the electricity to power it. But somebody at General Motors thought the idea to be sufficiently interesting to build a vehicle to show it off.

Thorium as a Power Source
Researchers in Russia, India and more recently, in China and North America, have studied using thorium as fuel for nuclear reactors, partly because it is more difficult to use in atomic weapons than uranium or plutonium. In addition, only a thin layer of aluminum foil is needed to shield people from the weakly emitting metal.

Although prototype thorium-fueled nuclear reactors have been developed, the technology has never been adopted for commercial use because the nuclear powers opted after the Second World War to focus on uranium-based atomic energy. (Incidentally, the major powers chose to focus on Uranium reactors precisely because it could be weaponized, Stevens has said).

Thorium-Based Laser
Stevens’ innovation is to use thorium to make a laser, not a nuclear power reactor.

Indeed, the use of radioactive materials in lasers is not unheard of either. After all, when Bell Labs researchers demonstrated the second laser ever in 1960, they used a flashlamp (a very bright light) to excite a crystal of uranium-doped calcium fluoride to lase in the infrared light spectrum. Because of the need for a cryogenic (ultralow-temperature) system to cool the hot laser-gain medium during operation, however, uranium lasers never found much practical use.

The key twist to Stevens’ thorium-laser power concept is that it would use a radioactive element-based laser to produce heat, not a beam of coherent light.

Remaining Technical Hurdles
Stevens says that developing a compact turbine and generator set is proving to be more difficult than making the thorium laser itself. “We can build the laser, but the biggest problem has turned out to be integrating it efficiently with the turbine and generator,” he notes. LPS’ thorium laser itself is simply an adaptation of the MaxFeLaser, a design Stevens built in 1985.

Stevens said his company has fabricated a modified Tesla turbine (no relation to the car company) to convert steam pressure into rotary motion. Unlike more familiar turbine types, a Tesla turbine is a bladeless centripetal-flow unit with a set of smooth disks that are placed in motion by directing moving gas, via nozzles, at the edges of the disks. The viscous (boundary-layer) drag on the disk surfaces that is produced by the gas flow causes them to rotate.

Further, after having found no off-the-shelf high-speed generators that fit his special application, his team has had to design a custom unit to efficiently produce electricity for his one-of-a-kind power plant.

Whether authorities will allow thorium-powered cars to roam the streets is another question. Stevens has not set a date for a prototype version.

Thorium lasers: The thoroughly plausible idea for nuclear cars | Txchnologist
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