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Nuclear powered aircraft

In the 1950/s the United States Airforce and Navy considered nuclear powered aircraft. Instead of burning fuel to heat air and provide thrust, a nuclear-powered jet engine would heat the air from the heat generated by a nuclear reactor. If it had worked, the aircraft could have remained airborne for months at a time, limited only by the endurance of the flight crew.
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Blast me to the moons!

Once you’ve learned how to tap nuclear energy, what can you do with it? One proposal was to take a couple thousand nuclear bombs, drop them behind a spacecraft, and set them off to push the craft from the Earth’s surface, into orbit, and then around the solar system. Called “project Orion,” it is undoubtedly the most spectacular use of nuclear energy ever seriously considered.
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Nuclear alchemy

The medieval alchemists wanted to change lead into gold. It was, by the methods they were attempting to use, impossible, but modern physics might be able to turn gold into lead. it is possible to change one chemical element into another. In nuclear reactors, with all those neutrons flying about, materials that absorb the neutrons are changed.
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Isotopes and enrichment

A given element can have different numbers of neutrons. While the protons determine an elements chemical properties, the different number of neutrons can have different nuclear properties. Uranium occurs naturally with mostly u238, with only about 0.07 percent of it occurring as u235. It’s the uranium 235 that can support a nuclear chain reaction. For most nuclear power reactors, you need around 4 or 5 percent of the uranium to be u235. If you want a nuclear explosion, it requires more than 90 percent. The process of increasing the percentage of 235 in uranium is called “Enrichment,” and it is a difficult and dangerous process.
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Let’s relax with nuclear physics

I’d like to thank john peacocke for giving me the idea for the next few episodes. We’ve been chatting via email, and he told me about molten salt nuclear reactors. That reactor and the general subject are interesting, and they make a nice break from the if and maybe of things like biology and evolution that we have been and will be talking about. Today, we cover the basics of nuclear fission.