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Tuesday, March 25, 2008

Nuclear Energy, Part I


Mr. Tucker is a veteran journalist whose work has appeared in several major national publications and in four of his books. His honors include the John Hancock Award, Gerald Loeb Award, Amos Tuck Award and Mencken Award for outstanding writing.

One form of alternative energy often is mistakenly grouped with solar: geothermal energy. Geothermal is produced when the natural heat of the earth comes in contact with groundwater. This can produced geysers and fumaroles – steam leaks that are now being harnessed to produce electricity.Where does the heat come from? Temperatures at the earth’s core reach 7,000 degrees Centigrade, hotter than the surface of the sun. Some of this heat comes from gravitational pressures and the leftover heat from the collisions of astral particles that led to the formation of the earth.

But at least half of it (we don’t know the precise percentage) comes from the radioactive breakdown of thorium and uranium within the earth’s mantle. This is terrestrial energy and a nuclear reactor is simply the same process carried out in a controlled environment.

In order to harness terrestrial energy in the form of uranium isotopes, we mine it, bring it to the surface, concentrate it and initiate a chain reaction that releases stored energy in the form of heat – the very same process as that used to harness solar energy from coal.

When Albert Einstein signed the letter to President Roosevelt informing him of the discovery of nuclear energy, he turned to some fellow scientists and said: “For the first time mankind will be using energy not derived from the sun.”This potential (for nuclear energy) is good news in terms of our energy needs and the environment. It means that the amount of fuel required to produce an equivalent amount of energy is now approximately two million times smaller.

Consider: At an average 1,000 megawatt coal plant a train with 110 railroad cars, each loaded with 20 tons of coal, arrives every five days. Each carload will provide 20 minutes of electricity. When burned, one ton of coal will throw three tons of carbon dioxide into the atmosphere. We now burn 1 billion tons of coal a year – up from 500 million tons in 1976. This coal produces 40 percent of our greenhouse gases and 20 percent of the world’s carbon emissions.

By contrast, consider a 1,000 megawatt nuclear reactor. Every two years, a fleet of flatbed trucks pulls up to the reactor to deliver a load of fuel rods. These rods are only mildly radioactive and can be handled with gloves. They will be loaded into the reactor, where they will remain for six years (only one-third of the rods are replaced at each refueling.)
The replaced rods will be removed and transferred to a storage pool inside the containment structure, where they can remain indefinitely (three feet of water blocks the radiation). There is no exhaust, no carbon emissions, no sulfur sludge to be carted away hourly and heaped into vast dumps.

There is no release into the environment.The fuel rods come out looking exactly as they did going in, except that they are now more highly radioactive. There is no air pollution, no water
pollution and no ground pollution.

A spent fuel rod is 95 percent U-238. This is the same material we can find in a shovel full of dirt from our back yards. Of the remaining 5 percent, most is useful, but small amounts should probably be placed in a repository such as Yucca Mountain.

The useful parts – uranium-235 and plutonium (a manmade element produced from U-238) -- can be recycled as fuel. In fact, we are currently recycling plutonium from Russian nuclear missiles. Of the 20 percent of our power that comes from nuclear sources, half is produced from recycled Russian bombs.

Many of the remaining isotopes are useful in industry or radiological medicine – now used in 40 percent of all medical procedures. It is only cesium-137 and strontium-90, which have half-lives of 28 and 30 years respectively that need to be stored in protective areas.

Unfortunately, federal regulations require all radioactive byproducts of nuclear power plants to be disposed of in a nuclear waste facility. As a result, more than 98 percent of what will go into Yucca Mountain is either natural uranium or useful material.Canada, Britain, France and Russia are all recycling their nuclear fuel.

France has produced 80 percent of its electricity with nuclear power for the last 25 years. It stores all its high-level “nuclear waste” in a single room at LeHavre.
(Reproduced by permission from Imprimis, a publication of Hillsdale College.)