Uranium is a radioactive chemical element found in nature and used mainly for the production of electricity. In addition to energy, uranium is used in medical procedures and, unfortunately, in nuclear bombs.
Uranium is represented by the symbol "U" and is composed mostly of the U-235 and U-238 isotopes. 99.7% of uranium is composed of isotope 238 and only 0.7% of isotope U-235.
This element was discovered in Germany in the year 1789 and its name was a tribute to the planet Uranus, discovered 8 years earlier. Its radioactivity, however, was only discovered in 1896.
Uranium is the last natural element on the periodic table and has the heaviest atomic nucleus in nature. It is from the fission of its core that electrical energy is produced.
Electric energy produced from uranium is an alternative to fossil fuels such as oil and coal. Today, 16% of the world's electricity comes from uranium.
Uranium ore.
Understand what the radioactivity.
Uranium Characteristics
- Under normal conditions of temperature and pressure, it is solid.
- It has a silvery gray coloration.
- It is a radioactive metal and its reactivity increases as the temperature rises.
- It has high density and hardness.
See also the meaning of natural resources.
Uranium in Brazil
Brazil is the 7th largest uranium reserve in the world, but it can move up in that position, as only 30% of its territory has been researched. This means that there may be uranium mines in Brazilian territory that are still unknown.
The main uranium mines in Brazil are Caetité in Bahia and Santa Quitéria in Ceará. Altogether, they are produced 276,000 tons of uranium per year in the country.
From the mines, the extracted uranium is transported to the city of Rezende, in Rio de Janeiro, where the Angra I and Angra II nuclear plants are located.
In Brazil, 99% of uranium is used for energy generation, the remaining 1% is used in medicine and agriculture.
Uranium in the World
The largest uranium reserves in the world are located in Australia, followed by Kazakhstan, Russia, Canada, Niger, South Africa and Brazil.
In terms of electricity production, Canada, Kazakhstan and Australia are the world leaders and together produce more than half of the planet's nuclear energy.
Check the reserves and production of each of these countries in the table:
| Parents |
Uranium Reserve Thousand tons/year |
Enriched Uranium Production Tons/year |
|---|---|---|
Australia |
1.661 | 7.743 |
| Kazakhstan | 629 | 7.994 |
| Russia | 487 | 3.239 |
| Canada | 468 | 10.485 |
| Niger | 421 | 3.355 |
| Brazil | 276 | 238 |
Uranium and nuclear energy
The isotope that can produce energy from the fission of the core is U-235, which is available in lesser quantity, so the uranium is enriched.
For the production of electrical energy, the concentration of U-235 must be between 3% and 4%. Uranium enrichment can be done through two different processes: ultra centrifugation and gaseous diffusion. Both processes separate isotopes to increase the concentration of U-235.
THE nuclear energy is considered an energy clean, as it does not emit greenhouse gases and generates little waste. Other advantage of this energy is the transport and storage, as it takes up little space.
An enriched uranium wafer is 1 centimeter long by 1 centimeter in diameter and its efficiency energy is very high: with two tablets it is possible to generate energy for a house with 4 people for a month whole.
Therefore, it is an excellent alternative to oil and coal, which in addition to the negative effects on the environment, occupy more space: 1 kg of uranium produces electricity equivalent to 10 tons of oil and 20 tons of coal.
the uranium cycle
After being taken from nature and enriched, the uranium is crushed and grouped into small tablets. At this stage, the inserts are fragile and are subjected to high temperatures to become more resistant.
The hardened inserts are placed on strong alloy steel rods. Each rod holds 335 inserts and the set of 236 rods forms a metallic structure called fuel element, which will supply the reactor for power generation.
Once the fuel element is in the reactor, the fission process starts. The fission of the nucleus is caused by the bombardment of neutrons in the nucleus of uranium atoms.
When the neutron hits the nucleus, it splits in two and releases a lot of energy and other neutrons, which will bombard other nuclei, triggering a chain reaction.
This process generates heat that heats the water in the system. The steam from this water activates the turbines that, in operation, start to generate electricity.
understand more about nuclear fission.
Disadvantages of nuclear energy
One of the main disadvantages in relation to nuclear energy is the risk of nuclear accidents and the possibility of contamination of the environment. Areas contaminated by uranium become uninhabitable.
O nuclear waste it is also a negative consequence. Process residues cannot be reused and must be properly disposed of, as if they enter contact with humans, can cause diseases such as cancer, genetic mutations and even death immediate.
know more about nuclear energy and energy matrix.
Uranium and nuclear bombs
While for electricity generation, uranium must be enriched until it reaches 3% or 4% of uranium 235, to produce an atomic bomb, the proportion of this isotope must be at least 90%.
When enriched to these levels, the fission of the nucleus after being bombarded by neutrons is absurdly large, capable of causing tremendous damage.
The bomb dropped by the United States on the city of Hiroshima, in Japan, at the end of World War II, called little boy, was made with 50 kg of uranium 235. This bomb had the destructive potential equivalent to 15 thousand tons of TNT.
Cloud over Hiroshima after atomic bomb drop.
little boy produced heat waves of up to 4 thousand degrees and winds with a speed of 440 meters per second.
At the time of the explosion, the bomb killed 80,000 people and the radiation contaminated thousands more in the city. In addition to the deaths that still happen today, genetic damage caused by radiation will be felt by countless generations of victims.
