Monday, July 04, 2011

Want a True Stimulus? Thorium Reactors instead of Oil in Just Five Years

An abundant metal with vast energy potential could quickly wean the world off oil, if only Western political leaders would muster the will to do it, a UK newspaper says. James Quinn of The Telegraph makes the case for thorium reactors as the key to a fossil-fuel-free world within five years, and puts the ball firmly in President Barack Obama's court, see his article Obama could kill fossil fuels overnight with a nuclear dash for thorium.

Thorium, named for the Norse god of thunder, is much more abundant than uranium and has 200 times that metal's energy potential. Thorium is also a more efficient fuel source -- unlike natural uranium, which must be highly refined before it can be used in nuclear reactors, all thorium is potentially usable as fuel. It is so abundant that it's almost an annoyance. Thorium is considered a waste product when mining for rare-earth metals.

Thorium-fueled MSR reactor,
click here for details.
The Telegraph says a $1.8 billion (£1.2 billion) project could lead to a network of tiny underground nuclear reactors, producing about 600 MW each. Their wee size would negate the enormous security apparatus required of full-size nuclear power plants. Thorium also solves the non-proliferation problem. Nuclear non-proliferation treaties (NPT) prohibit processes that can yield atomic bomb ingredients, making it difficult to refine highly radioactive isotopes. But thorium-based accelerator-driven plants only produce a small amount of plutonium, which could allow the U.S. and other nations to skirt NPT.

The Telegraph says Obama needs a Roosevelt moment, recalling the famous breakfast meeting when Albert Einstein convinced the president to start the Manhattan Project. A thorium stimulus could be just what the lagging economy needs.

(Summarized from Rebecca Boyle, Development of Tiny Thorium Reactors Could Wean the World Off Oil In Just Five Years, Popular Science, August 2010)

Newer nuclear reactor designs, collectively called Generation IV, include the thorium-powered molten-salt reactor (MSR). In an MSR, liquid thorium would replace the solid uranium fuel used in today’s plants, a change that would make meltdowns all but impossible.

MSRs were developed at Tennessee’s Oak Ridge National Laboratory in the early 1960s and ran for a total of 22,000 hours between 1965 and 1969. “It was not a full system, but it showed you could successfully design and operate a molten-salt reactor,” says Oak Ridge physicist Jess Gehin, a senior program manager in the lab’s Nuclear Technology Programs office.

The MSR design has two primary safety advantages. Its liquid fuel remains at much lower pressures than the solid fuel in light-water plants. This greatly decreases the likelihood of an accident, such as the hydrogen explosions that occurred at Fukushima. Further, in the event of a power outage, a frozen salt plug within the reactor melts and the liquid fuel passively drains into tanks where it solidifes, stopping the fission reaction. “The molten-salt reactor is walk-away safe,” Kutsch says. “If you just abandoned it, it had no power, and the end of the world came--a comet hit Earth--it would cool down and solidify by itself.”

Because of this efficiency, a thorium MSR would produce far less waste than today’s plants. Uranium-based waste will remain hazardous for tens of thousands of years. With thorium, it’s more like a few hundred. As well, raw thorium is not fissile in and of itself, so it is not easily weaponized. “It can’t be used as a bomb,” Kutsch says. “You could have 1,000 pounds in your basement, and nothing would happen.”

 One ton of thorium: as much energy
as 200 tons of uranium
One nuclear plant provides the energy equivalent of 1,200 windmills or 20 square miles of solar panels.Without the need for large cooling towers, MSRs can be much smaller than typical light-water plants, both physically and in power capacity. Today’s average nuclear power plant generates about 1,000 megawatts. A thorium-fueled MSR might generate as little as 50 megawatts. Smaller, more numerous plants could save on transmission loss (which can be up to 30 percent on the present grid). The U.S. Army is interested in using MSRs to power individual bases, Kutsch says, and Google, which relies on steady power to keep its servers running, held a conference on thorium reactors last year. “The company would love to have a 70- or 80-megawatt reactor sitting next door to a data center,” Kutsch says.

Even with military and corporate support, the transition to a new type of nuclear power generation is likely to be slow, at least in the U.S. Light-water reactors are already established, and no regulations exist to govern other reactor designs. Outside the U.S., the transition could come more quickly.

In January 2011 the Chinese government launched a thorium reactor program. “The Chinese Academy of Sciences has approved development of an MSR with relatively near-term deployment--maybe 10 years,” says Gehin, who thinks the Chinese decision may increase work on the technology worldwide. Even after Fukushima, “there’s still interest in advanced nuclear,” he says. “I don’t see that changing.”

(Summarized from Kalee Thompson, Concepts & Prototypes: Two Next-Gen Nukes, Popular Science, July 2011)

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