Advocates of thorium to power nuclear plants say that the element is safer than uranium, and that its waste cannot -- like the plutonium waste of uranium fission -- be re-formulated for nuclear weapons. Thorium plants, they say, also wouldn't need containment domes like those pictured here because the reactors can't "melt down" and release radiation. (iStock)

Thorium, a naturally occurring radioactive element found in abundance in the Earth’s crust all around the world, might well be a better fuel source than uranium for nuclear power generation for a variety of reasons. First and foremost, just one ton of the silvery metal can produce as much energy as 200 tons of uranium or 3.5 millions tons of coal, according to Nobel laureate Carlo Rubbia of the European Organization for Nuclear Research. Another advantage is that it comes out of the ground as a 100 percent pure, usable isotope. Unlike uranium, which contains only 0.7 percent fissionable material, thorium doesn’t require enrichment to be used in nuclear reactors. Also, the spent-fuel waste from thorium fission cannot be re-formulated for nuclear weapons like plutonium, the waste product of uranium-based fission.

Also, proponents say that thorium doesn’t require the high temperatures and mitigation equipment of uranium-based reactors. “The plants would be much smaller and less expensive,” Kirk Sorensen, a former NASA rocket engineer and now chief nuclear technologist at Teledyne Brown Engineering, told the UK’s Telegraph last year. “You wouldn’t need those huge containment domes because there’s no pressurized water in the reactor.” With no high temperatures, thorium reactors can’t “melt down” and release radiation.

“Once you start looking more closely, it blows your mind away,” adds Sorensen. “You can run civilization on thorium for hundreds of thousands of years, and it’s essentially free.” The advocacy-oriented Thorium Energy Alliance reports that there is “enough thorium in the U.S. alone to power the country at its current energy level for over 1,000 years.”

Nuclear researchers in the U.S. first contemplated using thorium as a nuclear energy feedstock back in the 1940s, but its lack of feasibility in making nuclear weapons put it on the back burner, where it has sat for the last six decades despite various attempts to revive the technology for practical use. In Russia, China and India, thorium reactors represent the next generation of nuclear power. India possesses about a quarter of the world’s thorium reserves. The country is working to develop a network of large thorium-based reactors, and plans to meet 30 percent of its electricity needs with thorium by 2050.

Many nuclear advocates and environmentalists alike don’t see thorium as the savior its supporters make it out to be. For one, uranium is still relatively easy to come by and inexpensive, and the nuclear industry is set up to run on it. Changing over to thorium would be expensive, and who knows what unforeseen problems may arise with full-scale deployment. Perhaps most important, some analysts worry that putting more eggs into humanity’s nuclear basket will surely further delay the transition to a truly green economy that runs on clean renewable energy from the sun, wind and other so-called alternative sources.

CONTACTS: CERN, www.cern.ch; Thorium Energy Alliance, www.thoriumenergyalliance.com; Teledyne Brown Engineering, www.tbe.com.

Dear EarthTalk: With plug-in hybrid and electric cars due to hit the roads sometime soon, will there be places to plug them in besides at home? And if so, how much will it cost to re-charge?

– Nicole Koslowsky, Pompano Beach, FL

Gasoline-electric hybrids, like the Toyota Prius, are all the rage due to their fuel efficiency, and consumers have been clamoring for carmakers to up the ante and give these vehicles a plug. This way the batteries can be charged at home and not just by the gas engine and other on-board features, thus greatly reducing the need for gas except for long trips. And purely electric cars, like the Tesla Roadster already on the market, will be making more appearances on the streets as greater production brings the costs down.

So what’s an electric or plug-in hybrid driver to do when they need a charge and they’re nowhere near home? Plug-ins are expected to reach up to 60 miles on a charge (great for a commute but not for a longer trip); and though the Tesla reportedly went 241 miles on a charge in a recent European road rally, its everyday stop-and-go efficiency will likely be less and drivers will need “pit stops” far from home.

A few forward-thinking large companies have installed electric outlets accessible to employee parking, but most plug-in hybrid and electric car drivers will be looking for help well beyond the scope of their commutes. In the U.S., several cities in California, as well as Seattle, Chicago, Phoenix and others are now setting up recharging infrastructures. Paris, where Toyota is testing plug-in hybrids, already has over 80 recharging stations throughout the city and suburbs. Across the channel, London is working with the nonprofit Environmental Defense to install upwards of 40 electric recharging stations around town.

According to the California Cars Initiative (CalCars), which promotes plug-in hybrids, Americans recharging their plug-ins via a regular 120V outlet should expect to pay about $1 per gallon equivalent. “Using the average U.S. electricity rate of nine cents per kilowatt-hour (kWh), 30 miles of electric driving will cost 81 cents,” the group maintains. “If we optimistically assume the average U.S. fuel economy is 25 miles per gallon, at $3.00 gasoline this equates to 75 cents a gallon for equivalent electricity.”

For its part, Toyota has already released a few hundred plug-in Priuses in the U.S. to university and commercial fleet customers. The company will monitor the vehicles’ performance and use the data to tweak the design for a consumer-friendly version sometime after 2010. Pricing on the vehicles, which get 65 miles per gallon or more in combined gas/electric mode and can run on electricity alone, is as yet undecided. But chances are the car will command a premium of several thousand dollars over the cost of a regular hybrid Prius. The fact that such a feature might obviate the need for gasoline entirely-save for long trips away from charging facilities-may well make it worth the extra up-front cost for some buyers.

Those unwilling to wait for a mass-market plug-in can have their existing Prius or Ford Escape hybrid converted accordingly by any of several “aftermarket” companies at a cost of $6,000 and up. CalCars provides a comprehensive listing of vendors across the U.S. and elsewhere that can do the conversions, and also offers its own instructions for those engineering-savvy hybrid owners who can do it themselves.

CONTACTS: Tesla Motors, www.teslamotors.com; Environmental Defense, www.edf.org; California Cars Initiative, www.calcars.org; Toyota, www.toyota.com.

Dear EarthTalk: Are plans to mine uranium near the Grand Canyon, as proposed by the Bush administration in 2008, still underway? -- Denton Chase, Half Moon Bay, CA

The Obama administration has been quick to overturn several anti-environmental moves ushered in during the 11th hour of George W. Bush’s presidency, but halting uranium exploration and mining near the Grand Canyon has not been one of them.

Last fall, Bush’s Secretary of the Interior, Dirk Kempthorne, circumvented a prohibition on mining activities by authorizing uranium exploration within a million acre buffer zone around Grand Canyon National Park. Recent spikes in the price of uranium-perhaps due to renewed interest in nuclear power as an alternative to fossil fuels as global warming makes its presence felt-have led to a surge in applications for new uranium mining permits on otherwise protected federal lands.

Green groups fear that once mining starts near the Grand Canyon, similar destructive plans will also get the green light in and around other protected areas, including Arches National Park, Capitol Reef National Park, Canyonlands National Park and the proposed Dolores River Canyon wilderness area.

When Kempthorne first proposed opening up the land to uranium mining, several concerned parties-including dozens of elected officials, public utilities and Native American tribes-complained about potential threats to surface and ground water from such activities. They fear that uranium mining in the area could lead to the release of radioactivity and heavy metals like selenium into the Colorado River and its watershed, including within Grand Canyon National Park.

In lieu of federal action on the issue, green groups have taken up the cause. Some, like the Pew Environment Group, are lobbying President Obama to overturn the mining allowances; others are working the judicial angle. Three organizations-the Center for Biological Diversity, Grand Canyon Trust and Sierra Club-filed suit in federal court in October 2008 to block the Bureau of Land Management, which manages the area, from allowing uranium mining in what they consider risky and nationally significant areas. “This is an agency in dire need of leadership from the new administration,” says Taylor McKinnon, public lands program director at the Center for Biological Diversity. “The Grand Canyon deserves it.”

The battle over uranium mining near the Grand Canyon sheds light on an even larger issue: the 1872 Mining Law, enacted under President Ulysses S. Grant and still in effect today. Long a bone of contention along partisan lines, the law has so far opened up of some 350 million acres of public land across the western U.S. to virtually unchecked mining. Green groups maintain that the law, put in place to encourage westward expansion, no longer makes sense in the modern era of dwindling natural resources.

“Current federal policy that allows the mining industry to operate next to America’s national icons and against the will of local communities must be changed,” said Jane Danowitz, Pew’s U.S. public lands program director. “It’s time to modernize the nation’s 1872 mining law.”

CONTACTS: Center for Biological Diversity, www.biologicaldiversity.org; Sierra Club, www.sierraclub.org; Pew Environment Group, www.pewtrusts.org.

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