Monday, October 25, 2010

New Nukes

From Whole Earth Discipline: Why Dense Cities, Nuclear Power, Transgenic Crops, Restored Wildlands, and Geoengineering Are Necessary by Stewart Brand, pp. 81-82:

As to footprint, Gwymeth Cravens points out that “A nuclear plant producing 1,000 megawatts takes up a third of a square mile. A wind farm would have to cover over 200 square miles to obtain the same result, and a solar array over 50 square miles.” That’s just the landscape footprint. [....]

More interesting to me is the hazard comparison between coal waste and nuclear waste. Nuclear waste is miniscule in size—one Coke can’s worth per person-lifetime of electricity if it was all nuclear, Rip Anderson likes to point out. Coal waste is massive—68 tons of solid stuff and 77 tons of carbon dioxide per person-lifetime of strictly coal electricity. The nuclear waste goes into dry cask storage, where it is kept in a small area, locally controlled and monitored. You always know exactly what it’s doing. A 1-gigawatt nuclear plant converts 20 tons of fuel a year into 20 tons of waste, which is so dense it fills just two dry-storage casks, each one a cylinder 18 feet high, 10 feet in diameter.

By contrast, a 1-gigawatt coal plant burns 3 million tons of fuel a year and produces 7 million tons of CO2, all of which immediately goes into everyone’s atmosphere, where no one can control it, and no one knows what it’s really up to. That’s not counting the fly ash and flue gases from coal—the world’s largest source of released radioactivity, full of heavy metals, including lead, arsenic, and most of the neurotoxic mercury that so suffused the food chain that pregnant women are advised not to eat wild fish and shellfish. The air pollution from coal burning is estimated to cause 30,000 deaths a year from lung disease in the United States, and 350,000 a year in China.

As for comparing full-life-cycle, everything-counted greenhouse gas emissions, a study published in 2000 by the International Atomic Energy Agency shows total lifetime emissions per kilowatt-hour from nuclear about even with those of wind and hydro, about half of solar, a sixth of “clean” coal (if it ever comes), a tenth of natural gas, and one twenty-seventh of coal as it is burned today.

And what can we do with the nuclear waste? Lawrence Livermore National Laboratory has an interesting idea: the Laser Inertial Fusion Engine (LIFE), a combined fusion/fission reactor in which the high-energy neutrons produced by fusion “burn” fissile material, like “depleted uranium; un-reprocessed spent nuclear fuel (SNF); natural uranium or natural thorium; or [...] plutonium-239, the minor actinides such as neptunium and americium, and the fission products separated from reprocessed SNF.” The result? “The LIFE engine extracts more than 99 percent of the energy content of its fuel, compared to less than 1 percent of the energy in the ore required to make fuel for a typical LWR [Light Water Reactor]. Higher fuel utilization means that far less fuel is required to generate the same amount of energy. A 1,500-megawatt LIFE power plant could operate for 50 years on only a small roomful of fuel.” The “remaining waste has such a low actinide content that it falls into DOE’s lowest attractiveness category for nuclear proliferation.” Securing the waste apparently won’t be much of a problem, because “the waste is self-protecting for decades: its radiation flux is so great that any attempt at stealing it would be suicidal.” OK, that gives me pause for thought, but, then, that’s part of why nobody in their right mind would try to steal it. And for those not in their right minds, there’s the actual suicidally lethal radiation that sounds like it would kill them before they could steal the material. Fortunately, the volume of waste produced is relatively low: “[...] approximately 5 percent of that required for disposal of LWR SNF.”

Intriguing. All things being equal, I prefer pure fusion, but putting our nuclear waste to good use makes a lot of sense, since we have to do something with it one way or another, and extracting vast amounts of energy from it, while reducing its volume, seems like a good start. And dealing with that waste looks like a much smaller and more tractable problem than dealing with the wastes we’ve been spreading over the planet by burning coal.

The possibilities of fusion and/or LIFE reactors aside, I think Stewart Brand makes points concerning the desirability of current, and near-term, methods of fission power production that deserve careful consideration from everyone, especially my fellow environmentalists.

Thursday, October 7, 2010

Climate Change

From Whole Earth Discipline: Why Dense Cities, Nuclear Power, Transgenic Crops, Restored Wildlands, and Geoengineering Are Necessary by Stewart Brand, pg. 9:

Climate is so full of surprises, it might even surprise us with a hidden stability. Counting on that, though, would be like playing Russian roulette with all the chambers loaded but one.