Dec 22, 2009

Uranium Is So Last Century... Enter Thorium

Little progress in 50 year old theory - reinventing cold war energy
WIRED- Published in 1958 ....what caught Sorensen's eye was the description of Weinberg's experiments producing nuclear power with an element called thorium.
..., during which he became convinced that thorium could solve the nuclear power industry's most intractable problems. After it has been used as fuel for power plants, the element leaves behind minuscule amounts of waste. And that waste needs to be stored for only a few hundred years, not a few hundred thousand like other nuclear byproducts.

Because it's so plentiful in nature, it's virtually inexhaustible. It's also one of only a few substances that acts as a thermal breeder, in theory creating enough new fuel as it breaks down to sustain a high-temperature chain reaction indefinitely. And it would be virtually impossible for the byproducts of a thorium reactor to be used by terrorists or anyone else to make nuclear weapons.

Weinberg and his men proved the efficacy of thorium reactors in hundreds of tests at Oak Ridge from the '50s through the early '70s. But thorium hit a dead end. Locked in a struggle with a nuclear- armed Soviet Union, the US government in the '60s chose to build uranium-fueled reactors — in part because they produce plutonium that can be refined into weapons-grade material. The course of the nuclear industry was set for the next four decades, and thorium power became one of the great what-if technologies of the 20th century.

The concept of nuclear power without waste or proliferation has obvious political appeal in the US, as well. The threat of climate change has created an urgent demand for carbon-free electricity, and the 52,000 tons of spent, toxic material that has piled up around the country makes traditional nuclear power less attractive. President Obama and his energy secretary, Steven Chu, have expressed general support for a nuclear renaissance. Utilities are investigating several next-gen alternatives, including scaled-down conventional plants and "pebble bed" reactors, in which the nuclear fuel is inserted into small graphite balls in a way that reduces the risk of meltdown.

Those technologies are still based on uranium, however, and will be beset by the same problems that have dogged the nuclear industry since the 1960s. It is only thorium, Sorensen and his band of revolutionaries argue, that can move the country toward a new era of safe, clean, affordable energy.

CEO Seth Grae thinks it's better business to convert existing reactors than it is to build new ones. "We're just trying to replace leaded fuel with unleaded," he says. "You don't have to replace engines or build new gas stations."...For Sorensen, putting thorium into a conventional reactor is a half measure, like putting biofuel in a Hummer. But he acknowledges that the seed-and-blanket design has potential to get the country on its way to a greener, safer nuclear future. "The real enemy is coal," he says. "I want to fight it with LFTRs — which are like machine guns — instead of with light-water reactors, which are like bayonets. But when the enemy is spilling into the trench, you affix bayonets and go to work."

The thorium battalion is small, but — as nuclear physics demonstrates — tiny forces can yield powerful effects.

Please read full at WIRED