Following the agreement with Iran - everything about nuclear and uranium

From heavy memes to a dirty bomb. The Little Ma'or presents an enrichment course

What is uranium?
Uranium is a silvery white heavy metal. It exists in nature in the form of ore and its largest deposits in nature are found in the USA, Canada, Australia and DRAP. Uranium is one of the heaviest elements in nature, and each of its atoms has 92 protons (positively charged particles) in its nucleus. However, as in many other elements, the number of neutrons in the nucleus is not uniform. In its most common form, the nucleus has 146 neutrons. This form, known as uranium-238 (92 protons + 146 neutrons), is the most stable and most common in nature. However, 0.71% of the uranium in nature exists in another form - uranium-235. This isotope has only 143 neutrons in the nucleus, and is much less stable. If by chance one neutron is added to the nucleus, the business simply collapses: the nucleus fissions, and in fact the uranium turns into two different elements (barium and krypton). Therefore, uranium-235 is also called a fissile material, because its nucleus fissions easily.

What is a nuclear reaction?
When the nucleus of an atom splits, enormous energy is released. On top of that, radiation and three orphan neutrons are released, which do not belong after the two substances created. If there are more uranium-235 atoms in the environment, these neutrons may damage their nucleus, causing them to fission, thus causing the release of more neutrons and creating a chain reaction. If there are enough fissile atoms around, a nuclear explosion may occur. The amount of fissile material needed to create such an explosion is known as "critical mass".

What is enriched uranium?
In natural uranium, more than 99% of the atoms are stable uranium-238, and only about 0.7% is fissile material. To create a substance that can be used in a nuclear reaction - in fuel or in a bomb - the concentration of uranium-235 must be increased, this process is called enrichment. When we speak, for example, of uranium enriched to 20%, it means that 20% of the atoms in the material are uranium-235.

How is uranium enriched?
To enrich uranium, the two main forms need to be separated. Since the only difference between the two types of atoms is their mass (that is, the weight), the most effective method is the use of a centrifuge. It is simply a merry-go-round that spins at enormous speed so that the heavier atoms are pushed farther from the center. However, in order to separate uranium using this method, it is impossible to use a solid, and the uranium must be transferred to a gaseous state. Since pure uranium turns into a gas at a temperature of almost 4,000 degrees, a compound of uranium is usually created with fluorine (yes, the substance that protects the teeth), which evaporates at a temperature of several tens of degrees. However, uranium-fluorine is a very corrosive and dangerous compound, so the centrifuges must be built from special metals. The mass differences between the two forms of uranium are quite small (less than XNUMX percent), so separation in a single centrifuge is not sufficient. To get a high-level enrichment, you take the separated material from one centrifuge, transfer it to another centrifuge, at a slightly different speed, and repeat the process thousands of times. To maintain an efficient process, thousands of hubs are needed, in an array sometimes known as a cascade.

How is uranium used to generate electricity?
As in a normal power plant, energy is produced by burning fuels, in a nuclear power plant, the heat generated in a nuclear reaction is used in a similar way. To create a nuclear reaction to generate electricity, it is enough to enrich the uranium to a level of 3-5 percent. To produce a nuclear bomb, the uranium must be enriched to a level of about 90%. Uranium enriched to a level of more than 20% is considered highly enriched (and subject to stricter control rules).

What is plutonium?
Plutonium is an even heavier element than uranium, and is almost non-existent in nature. It also has a fissile nucleus like that of uranium, and is used in certain types of nuclear bombs. To produce plutonium, uranium atoms are taken, and protons and neutrons are added to their nucleus in a special (and dangerous) process.

What is heavy water?
Just as there are different forms of uranium, which differ in the number of neutrons in the nucleus, hydrogen also has such different forms. The normal nucleus of hydrogen (that is, the common form in nature) does not have any neutrons, but there are forms of hydrogen that have one, or even two, neutrons in their nucleus. Water as we know is composed of oxygen and hydrogen, and if it is composed of heavier hydrogen, it is called heavy water. Unlike normal water, the heavy water almost does not absorb neutrons, so if plutonium production is done inside it, there is a higher chance that the neutrons will be absorbed by the uranium nucleus, and not be swallowed by water molecules.

What are radioactive materials?

There are certain types of atoms that are more prone than others to undergo spontaneous fission. That is, their nucleus disintegrates by itself, without external intervention. Also in this process, as in external fission, radiation is released. During a nuclear explosion, many neutrons are released at a very high intensity, destabilizing other materials, and making them radioactive as well. Atoms formed from the decay of uranium and plutonium may also be radioactive. All these materials are called "nuclear fallout". A bomb consisting of radioactive materials that do not fission (and a conventional explosive) is called a "dirty bomb". It cannot, of course, cause a nuclear explosion, but it can cause local radioactive contamination, and above all, sow a lot of panic.