Nuclear Fission for Dummies: Enriched vs Depleted Uranium

We’ve all heard the nuclear jargon thrown carelessly about by both critics and proponents of nuclear technology. Enriched Uranium this and Depleted Uranium that. You might be asking yourself “What does all this mean?”

Here are some of the basics:

Hopefully, you learned in high school science class that all atoms are made up of three subatomic particles: Protons (positive electrical charge), Neutrons (neutral charge), and Electrons (negative charge).

All Uranium atoms contain 92 Protons, hence its home as #92 on the Periodic Table. Different Isotopes of Uranium have different numbers of Neutrons in the nucleus, thus they have a different mass. The two most common Uranium isotopes are Uranium 235 (92 protons + 143 neutrons = 235 AMU of mass) and Uranium 238 (92 protons + 146 neutrons = 238 AMU).

Uranium Ore

Raw Uranium Ore, Uranium dug out of the ground that is, contains 99.284% Uranium 238 and only 0.711% Uranium 235. U-235 is known as fissile Uranium. Fissile Uranium is the type required for Nuclear Fission (the splitting of an atom). In order to make Uranium ore into useful fuel, the Enrichment process is required.

Uranium Enrichment Process

Uranium enrichment is grossly complicated but in a nutshell we put the stuff in a centrifuge and spin the heebie-jeebies out of it. After this process is completed we are left two different materials:

1. Enriched Uranium (higher concentration of U-235) which can be used as Nuclear Fuel, or if enriched far beyond that point can be used for Nuclear Weapons.

2. Depleted Uranium (lower concentration of U-235) which is often used by the military for armor piercing projectiles.

In order for a sample of Enriched Uranium to be considered weapons-grade, the Uranium must be Highly Enriched (85% U-235 or higher). To put this in perspective the most common fuel used in American nuclear power plants is enriched to only 3-5% U-235. This makes the distinction between civilian nuclear fuel and nuclear weapons very simple and easily determined.

Image Credit

Uranium Ore and Uranium 238 images courtesy of Flickr user bionerd published under the CC license.

Gas centrifuges enriching Uranium, Ohio courtesy of Flickr user BlatantNews.com released to the Public Domain.