Most enrichment processes involve only natural, long-lived radioactive materials. Uranium is only weakly radioactive, but its chemical toxicity is much more significant. Thus protective measures required for an enrichment plant are similar to those in other chemical industries. When exposed to moisture, uranium hexafluoride forms a very corrosive acid , hydrofluoric acid. Any leakage of this chemical is undesirable and to prevent this almost all areas of an enrichment plant keep the uranium hexafluoride gas below atmospheric pressure.
Additionally, double containment is provided in areas where higher pressures are required and venting gases are collected and treated. Previously enrichment has been the main source of greenhouse gases from the nuclear fuel cycle as electricity used for enrichment was generated using coal.
Although there are associated greenhouse gas emissions , it is only about 0. Fossil Fuels. Nuclear Fuels. Acid Rain. Climate Change. Climate Feedback. Ocean Acidification. Rising Sea Level. Figure 3. Now that President Donald Trump has pulled the United States out of the nuclear deal with Iran, people across the world are wondering if the Middle Eastern country will invest its energies in building a nuclear weapon. But if Iran's leadership does decide to pursue an atomic bomb, how would researchers get enough uranium, the key ingredient?
Uranium enrichment is one of the key steps in building nuclear weapons. Only a certain type of uranium works in nuclear reactors and bombs. Separating that type of uranium from the more common variety requires a great deal of engineering skill, despite the fact that the technology needed to do it is decades old.
The challenge lies not in figuring out how to separate uranium, but in constructing and running the equipment needed for the task. Uranium atoms , like the atoms of every element, occur in nature in varieties called isotopes. Historically, conventional mines e. After mining, the ore is crushed in a mill, where water is added to produce a slurry of fine ore particles and other materials. The slurry is leached with sulfuric acid or an alkaline solution to dissolve the uranium, leaving the remaining rock and other minerals undissolved.
However, over half of the world's uranium mines now use a method called in-situ leaching, where the mining is accomplished without any major ground disturbance. Water injected with oxygen or an alkali, acid or other oxidizing solution is circulated through the uranium ore, extracting the uranium.
The uranium solution is then pumped to the surface. The vast majority of nuclear power reactors use the isotope uranium as fuel; however, it only makes up 0.
Other techniques exist such as laser and aerodynamic processes , but they are still experimental. Gaseous diffusion forces uranium hexafluoride gas through a series of semi-permeable membranes. The lighter, smaller U moves through the membrane easier than the larger heavier U After the UF 6 is enriched by the specified amount, then it condensed into a liquid and then solidified. Gas centrifuges uses centrifugal force rapidly rotating cylinders to separate the two isotopes from the UF 6 gas.
The heavier U atom moves up and outward, and the lighter U atom moves toward the center of the tube.
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