The ABCs of Nuclear Weapons: Understanding Uranium Enrichment – Why Israel Attacked Iran’s Site’s

Late last week, Israel carried out airstrikes on three of Iran’s major nuclear sites—Natanz, Isfahan, and Fordow. These sites are known to be well-protected and mostly located underground. During the attacks, several Iranian nuclear scientists were reportedly killed. However, there are mixed reports about the extent of the damage caused by the strikes, and it’s still unclear how badly the facilities were affected.

Natanz and Fordow are the places in Iran where uranium is processed to make it more powerful, a key step in making nuclear weapons. Isfahan is where the basic materials needed for this process are prepared. So, if these sites are damaged, it would slow down or weaken Iran’s ability to develop nuclear weapons. But what does “uranium enrichment” actually mean, and why is it a big deal?

To understand this, we first need to know a bit about the different types of uranium (called isotopes) and how nuclear energy is produced by splitting atoms in a process called nuclear fission.

What is an isotope?

Everything around us is made of atoms, and atoms are made up of protons, neutrons, and electrons. The number of protons in an atom decides which element it is—like hydrogen, oxygen, or uranium. Isotopes are simply different versions of the same element. They have the same number of protons but a different number of neutrons. This small difference can affect how the atom behaves, especially in nuclear reactions.

Atoms usually have the same number of protons and electrons. For example, a uranium atom has 92 protons, and a carbon atom has 6. But the number of neutrons in an atom can be different, even for the same element. When this happens, these different forms are called isotopes. So, isotopes are just versions of the same element that have more or fewer neutrons.

This difference in neutrons doesn’t really affect normal chemical reactions. But when it comes to nuclear reactions, it can make a big difference. Some isotopes can be used to create powerful energy or even nuclear weapons, while others cannot.

The difference between uranium-238 and uranium-235

When uranium is mined from the earth, almost all of it—about 99.27%—is a type called uranium-238, which has 92 protons and 146 neutrons. A very small amount—only 0.72%—is uranium-235, which also has 92 protons but only 143 neutrons. The rest, just 0.01%, is made up of other rare types of uranium.

To use uranium in nuclear power plants or weapons, we need to change the amounts of its different types (isotopes). This is because, out of the two main forms of uranium, only uranium-235 can keep a chain reaction going. In this process, one neutron splits a uranium-235 atom, releasing energy and more neutrons. These new neutrons then split other atoms, creating a repeating cycle that produces a lot of energy.

This chain reaction gives off an enormous amount of energy. In the case of a nuclear bomb, the aim is to make this reaction happen almost instantly—within a tiny fraction of a second—so that all the energy is released at once, causing a powerful explosion.

In civilian nuclear power plants, the chain reaction is carefully controlled to make sure it produces energy safely. Today, nuclear power provides about 9% of the world’s electricity. Another important peaceful use of nuclear technology is in the field of medicine. Special isotopes created through nuclear reactions are used to help diagnose and treat different health conditions, such as cancer and heart diseases.

How Nuclear Fission Happens : Explained

Nuclear fission is like breaking a big ball into smaller pieces—and getting a lot of energy in the process.

Start with a heavy atom – like uranium-235. Think of it like a big, unstable ball.
Hit it with a neutron – this is like throwing a small object at the ball.
The atom splits – when hit, the uranium atom breaks into two smaller atoms.
Energy is released – this split gives off a lot of heat and light energy.
More neutrons are released – when the atom splits, it also throws out more neutrons.
These neutrons hit other uranium atoms – starting the process again, like a chain reaction.

This chain reaction is what powers nuclear reactors (slow and controlled) and nuclear bombs (fast and uncontrolled).

So, What Does Uranium Enrichment Mean?

Uranium enrichment is the process of increasing the amount of uranium-235 — the part of natural uranium that can be used for nuclear energy or weapons. Natural uranium mostly contains uranium-238, which isn’t very useful for these purposes.

To enrich uranium, scientists separate out some of the uranium-238 and keep more of the uranium-235. The most common method used today is a machine called a centrifuge, which spins the uranium at high speeds to help with this separation. Countries like Iran also use this technique.

There are also newer methods being explored, like laser-based enrichment, with some recent developments coming from Australia.

Centrifuges are machines used to separate two types of uranium — uranium-235 and uranium-238. Uranium-238 is slightly heavier than uranium-235. To separate them, scientists turn uranium into a gas and spin it extremely fast — up to 70,000 times per minute — using a device like a spinning cylinder.

This spinning creates a strong force that pushes the heavier uranium-238 toward the outer edge, while the lighter uranium-235 stays more toward the center. By collecting the gas near the center, they get more of the uranium-235, which is needed for nuclear power and weapons.

It works kind of like a washing machine’s spin cycle: the heavier stuff moves outward, and the lighter stuff stays closer to the middle. This method doesn’t separate uranium-235 all at once, so the gas has to be spun many times in different machines to slowly increase the amount of uranium-235.

Most nuclear power plants don’t need a lot of uranium-235. They use what’s called “low enriched uranium,” which means only about 3% to 5% of the uranium in the fuel is uranium-235. That small amount is enough to keep a steady chain reaction going — which is what’s needed to produce electricity.

How much enrichment is needed for nuclear weapons?

To create a powerful explosion, uranium-235 must be enriched to a much higher level than what is used in power plants or for medical purposes.

While it’s possible to make a nuclear weapon using uranium that has been enriched to 20% (called “highly enriched uranium”), most countries that have nuclear weapons go much further. They usually enrich the uranium to around 90%, which is known as “weapons-grade” uranium. The higher the enrichment, the smaller and lighter the bomb can be — which makes it easier to deliver.

The International Atomic Energy Agency (IAEA) has reported that Iran has already enriched a large amount of uranium up to 60%.

Once uranium reaches 60%, it’s actually much easier to push it further to 90%, which is the level needed for nuclear weapons. That’s because by then, most of the heavier uranium-238 has already been removed, so there’s less left to separate out.

This is why Iran’s actions raise serious concerns about the possibility of making nuclear weapons. Also, because uranium enrichment is such a sensitive process, the technology behind it — especially centrifuges — is kept secret to prevent misuse.

In the end, the same centrifuge machines used to make fuel for nuclear power plants can also be used to make material for nuclear weapons.

It all depends on how much the uranium is enriched. If the machines keep running longer and increase the percentage of uranium-235, they can create material suitable for bombs instead of just electricity.

Inspectors from the International Atomic Energy Agency (IAEA) regularly check nuclear sites around the world to make sure countries are following the rules of the global nuclear non-proliferation treaty — an agreement that aims to stop the spread of nuclear weapons.

Iran says it is only enriching uranium for peaceful uses, like producing energy. However, just last week, the IAEA board decided that Iran has broken the rules of the treaty, raising concerns about its true intentions.

——– E.O.M

(Girish Linganna is an award-winning science communicator and a Defence, Aerospace & Geopolitical Analyst. He is the Managing Director of ADD Engineering Components India Pvt. Ltd., a subsidiary of ADD Engineering GmbH, Germany. Contact: girishlinganna@gmail.com )

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