Uranium enrichment: Death technology

According to experts, 1kg of uranium is enriched equivalent to 15,000 tons of TNT. The threat of an atomic bomb made of uranium for humans is no longer a story on books.

The fateful Uranium bomb

Sixty years have passed, but humanity, and first of all, the Japanese people have never been able to and never forget that horrifying Monday of 1945.

Photographs from Hiroshima City plane before and after the atomic bomb explosion on August 6, 1945. After the explosion (right photo), Hiroshima is only a plain. ( Photos from the internet ).

At 8:15 am on Monday morning, August 6, 1945, an atomic bomb was dropped on Hiroshima.

It was a bomb made of uranium fuel.

Little boy - The first atomic bomb in the world.The "core" of the bomb is 1kg of "rich" uranium with U-235 isotope constituents accounting for over 90%.The bomb exploded in Hiroshima (Japan) on August 6, 1945 and caused more than 20,000 deaths.

Although it is only 3.3 meters long, 0.7 meters in diameter, weighs 4 tons, it is called the "Little Boy" (Little Boy), but is as destructive as the 15,000 tons of conventional explosive TNT, it turned 92% of Hiroshima city into rubble and ash, killing more than 20,000 people.

In fact, that 4-ton bomb contained only 1 kilogram of net fuel, or in other words, only 1kg of uranium explosives with isotope components U235 accounted for over 90%.

So far, in the arsenals of nuclear nations there have been atomic bombs with tremendous destructive power greater, dozens and even hundreds of times than "The Young Boy" devastated Hiroshima in the past. .

But, whether small bombs or large bombs all require uranium enrichment technology to produce the necessary amount of rich uranium, that is, uranium has a very high U235 isotope composition.

So, how is U235 rich and enriched with uranium?

Rich uranium

Uranium element, discovered more than 200 years ago (in 1789) by chemist MG Klaporoot (German).

And this elemental name is the name to celebrate the discovery of Urani star, or Uranus in our solar system.

From the beginning, many common characteristics of Urani were discovered.

For example, it is heavy metal, silvery white, melting temperature 1133 degrees Celsius and boiling temperature of 3,500 degrees Celsius.

There is nothing worth noting if the Uranium element does not have a very important attribute - radioactivity.

Enrico Fermi (1901-1954). (Photo : cfo.doe.gov).

It was with the invention of natural radioactivity emitted from Uranium and Roman ore, Marie Curie and her husband (Pierre Curie) and his teacher (Henry Becquerel) were awarded the Nobel Prize in Physics in 1903.

Non-stop there, Marie Curie spent eight years searching for radioactive substances hidden in Uranium ore and giving mankind a precious tool to be used in medicine, geology, etc. And glory came to her again: A second Nobel Prize was honored with a special award for Marie Curie (1911), the Nobel Prize in Chemistry for inventing new elements never before known - Radium and Polonium.

But the most important and most significant for Urani is the fission nature of the U-235, made by prominent scientists E. Fermi (Italy), O. Hahn and Ph. Strassman (Germany) discovered in the 30s of the last century.

Under neutron action, the U -235 nucleus is split into two pieces, simultaneously releasing two to three new neutrons and emitting a large energy of 200 MeV (200 million electrons).

As mentioned above, only 1kg of rich Uranium in 'Little Brat' emitted enormous energy equivalent to 15,000 tons of TNT!

Nuclear fission: The neutrons that fire at the Uranium nucleus cause the Uranium nucleus to break out into many smaller nuclei and release an extremely large source of energy.(Source: ffden-2).

It is this property that turns uranium into an ideal fuel for military purposes, which is to produce nuclear explosives or peaceful applications for the construction of nuclear power plants (using nuclear energy. make electricity).

Geological documents indicate that natural uranium exists in the form of a mixture of U2O8 uranium oxide in pebble ore.

This ore is the starting material to prepare pure metal or other compounds.

Natural uranium.(Source: web.em.doe.gov).

They also determined that the amount of uranium present in the earth is relatively small, the average content in the rock accounts for only about three parts per million (3.10 4%), almost the same amount of other rare elements as Bo, Mliplip , Ytecbi and Tali.

Uranium metal consists of two major isotopes, U-238 and U-235.

In particular, U-238 accounted for 99.7% overwhelmingly. The U-235 isotope is too poor, accounting for only 0.3% (3 thousand). The rare thing is rare, but precious U-235. Because only the new U-235 joins a nuclear chain reaction, a reaction is needed to maintain the heating supply for the power plant's operation or to create the necessary explosion.

In other words, only this U-235 nucleus is the fuel of a nuclear power plant or 'explosive' of the atomic bomb.

In fact, it is difficult to extract an absolute amount of U-235.

U-235 isotope can only be enriched in the uranium metal mixture to a certain ratio. With about 5% richness (or 5% U-235), uranium mixed metal can be used as a fuel for nuclear power plants.

But as an atomic bomb, the U-235 must account for more than 90% of the uranium metal mixture. It is called "rich" uranium.

"Uranium enrichment" technology

Thus, the process of increasing the composition of U-235 in uranium mixed metal is called uranium enrichment technology.

This process becomes very important, if not the decision to transform uranium into such a rare material.

Currently, there are many methods for enriching uranium such as: Electromagnetic Isotope Separation , Thermal Diffusion , Gaseous Diffusion , Aerodynamic Processes , Copper Separation Laser Isotope Separation , Ionizing and Chemical Exchange ( Chemical and Ion Exchange ), Splitting Plasma ( Plasma Separation ) and Centrifugal Gas ( Gas Centrifuge ).

The common method for enriching Uranium is now the centrifugation method (Iran currently uses this method).

Want to achieve higher U-235 richness and gain a large amount of fuel, need more centrifuges, hundreds, thousands and even tens of thousands of machines.

Clearly, with hundreds of super centrifuges working at full capacity, Iran already has uranium enrichment technology.

Internationally, first of all the superpowers in the UN Security Council, are deeply concerned, which is understandable.

Not only that, Iran also increased the crisis of crisis by declaring its intention to build a heavy water nuclear reactor.

The centrifugation method for separating the isotope U 235 from U-238 is based on the difference in centrifugal force of lighter and heavier gas molecules. Separation by centrifugation is carried out in rotating cylinders. Combining different types of molecules when entering rotary cylinders is split into two lines. The heavier molecules are removed from the periphery of the centrifuge and move downwards along the outer wall, but those molecules are lighter but pushed into the center upwards along the axis of the cup. center. In this method, U 238 and U 235 only achieve complete separation when the gas mixture passes through the machine continuously thousands of times. (According to Mendeleep's "Circulatory Law and Circulatory System of Elements ". NPAgaphosin, Science and Technology Publisher, Hanoi-1981).

Tran Thanh Minh