Uranium - The Nuclear Fuel

Uranium is present naturally in all soil, rock and water. It doesn't exist in nature as a metal but as a mineral compound and is distributed through the environment by wind, rain and geologic processes. Rocks break down and turn to soil,  soil is washed away by water and then blown by the wind into rivers and lakes where it settles and again reforms back into rocks.

One ton of uranium can produce 40 million kilowatt-hours of electricity. This is equivalent to burning 16,000 tons of coal or 80,000 barrels of oil. The United States still has stockpiles of uranium from mining and the dismantling of nuclear warheads that can last another 30 years,  after which the uranium mines will be reopened.  There are abundant amounts of uranium in the United States that haven't been mined because there hasn't been any demand.  For this same reason no one has been searching for uranium either and there would be several more uranium deposits undiscovered.

Mined uranium has a series of metallurgical processes to crush, screen, and wash the ore, letting the heavy uranium settle as the lighter debris is funneled away. It then goes to the mill, often situated near the mine, where acid or alkali baths leach the uranium out of the processed ore, producing a bright yellow powder, called ‘‘yellowcake’’ that is about 75% uranium oxide (whose chemical form is U3O8).  This is the basis for fuel for nuclear power plants and it takes around 24 hours to turn the ore into yellowcake. 

In the cases where ores have a concentration of 0.1%, the milling must grind 1000 ton of rock to extract 1 ton of yellowcake. The tailings, remaining rocks or mine dumps,  require treatment and are the largest volume of nuclear waste in the United States but is low level waste.  The tailings are capped with rock and clay to avoid wind blowing the dust that may contain radon,  a byproduct of uranium when it decays.

Most future uranium mines will use "in-situ leaching",  also called solution mining,  which is less damaging to the landscape and requires far less fossil fuels than conventional mining techniques.  It also means there will be no tailings that may leave uranium byproducts to be disbursed.  Solution mining drills holes into the ground with no need for explosives or open pits and requires far less heavy equipment that emit fossil fuels. Today, uranium mining is the cleanest when compared to the other methods. Because of the density and abundant energy of uranium there is also less need for mining it than coal which is the biggest emitter of greenhouse gases. For instance,  one uranium fuel pallet, typically weighing 7 grams, produces the same amount of energy as  807,394 grams of coal (807.39kg or 1,780 pounds of coal).

When a uranium mine is decommissioned it is under strict regulations from the EPA and NRC to return the land to its previous condition,  at the mining companies expense.  All damage done to the terrain and pollution caused to the earth and water must be reversed.  The mining and milling (Front End) processes contributes approximately 25.09gCO2e/kWh out of a total of 66.08gCO2e/kWh emitted from the full life cycle of nuclear power. As mentioned above these estimates should decrease with new mining technologies being used in the future.