Archive for February, 2008

Radioactive coal

February 13th, 2008 by Gene
 
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There’s radiation all around us. And in some strange places. We’ll look, today on Engineering Works!

First, a question: would you rather live next door to a coal-fired power plant or a nuclear-powered one? You’d probably choose the coal plant. All that radiation from the nuclear plant, right?

Well, if you’re worried about radiation, either place is probably okay. Your risk of health problems in any year from nuclear power plant radiation is tiny. About one in a billion, with a B. But here’s the kicker: the radiation health risk from coal-fired plants is actually higher. About one in 10 million. Still really small, but 100 times higher than the nuclear plant.

Here’s why: When coal comes out of the ground, it has traces of radioactive uranium and thorium in it. No problem. They’re tiny. But most of the coal disappears when it’s burned, and the fly ash that comes out of the stack contains more uranium and thorium than the original coal did. Probably 10 times more.

Of course, you’re more likely to be struck by lightning than get sick from radiation from either kind of power plant. But it’s worth thinking about. We’re building a lot of power plants – both kinds. In China alone, a new coal-fired plant opens every week or two. In the United States, we’ll probably build 30 new nuclear plants over the next several decades.

Coal or nuclear, our power is about ready to be switched off. See you next time.

EngineeringWorks! is made possible by Texas A&M Engineering and produced by KAMU-FM in College Station. Learn more about engineering. Visit us on the World Wide Web. Engineeringworks.tamu.edu.

Outlaw engineers

February 7th, 2008 by Gene

Usually, engineers are the good guys. Sometimes they’re not. We’ll see, today on Engineering Works!

 
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We like to think that engineers do good things, and usually they do — build roads and bridges, design new cars and airplanes, find new materials. But occasionally, engineers turn up on the other side of the law.

Take the engineers that design elaborate tunnels that smugglers use to move bales of marijuana under the Mexico-California border. On the U.S. side of the border, one of these tunnels opened into a semi-trailer-sized shipping container in a warehouse. From there, it dropped 50 feet underground and ran through solid rock half a mile to an office building on the other side of the border fence.

The tunnel appeared to have been dug with professional mining tools and was carefully lit, ventilated and drained.

It’s not a small problem. Investigators have found almost 70 border-crossing tunnels, most under the border with Mexico. One crossed the border between Washington State and Canada. Most of them were pretty crude, but some – like the one we’ve been talking about – are really slick.

If engineers on the wrong side of the law helped the smugglers build the tunnels, other engineers have figured out a good way to put the tunnels out of action. Pour them full of concrete. Works like a charm.

There’s light at the end of our tunnel, so we’ll shut it down and get out. See you next time.

EngineeringWorks! is made possible by Texas A&M Engineering and produced by KAMU-FM in College Station. Learn more about engineering. Visit us on the World Wide Web. Engineeringworks.tamu.edu.