Nuclear energy
Nuclear energy is that energy released from a chemical reaction that involves changes in the nuclei of atoms.
Most chemical reactions take place involving electrons in the atom’s electrons.
However, there are elements that are capable of transforming into isotopes of the same element (when the number of protons does not change) or even into another element (when the number of protons also changes), through a nuclear reaction .
nuclear reaction
The nuclear reaction involves the emission of a very large amount of energy.
According to Einstein, during a nuclear reaction, mass is transformed into energy. This is what postulates the Principle of Equivalence between Mass and Energy, translated into the mathematical sentence:
E = m. c²
When the mass of an object is multiplied by the square of the speed of light in a vacuum, the result would be the maximum amount of energy that can be obtained in a nuclear reaction.
The speed of light in a vacuum has a very large value (approximately 300,000 km/sec), so even a small mass can produce enormous amounts of energy.
There are two types of nuclear reactions:
Nuclear fusion
Nuclear fusion occurs when atomic nuclei come together to form another element of a higher atomic number.
The nuclear fusion reaction consumes a lot of energy, but still, the amount of energy produced is greater than that consumed.
Science has not yet discovered a way to control nuclear fusion.
Nuclear fission
Nuclear fission is a reaction in which the nucleus of an unstable atom breaks, forming two other atoms of different elements (because they have a lower number of protons than the original element). It is for this reason that nuclear fission is also called nuclear transmutation.
Nuclear fission is achieved through particle bombardment; is a reaction in which energy is released (exothermic reaction)
The principle of nuclear fission is used in atomic bombs (when the chain reaction happens uncontrollably) and in the production of nuclear energy (when the reaction is controlled).
Nuclear energy
Nuclear fission was discovered in 1938 by Hahn and Strassmann in the German nuclear power project ; the process used was the bombardment of neutrons on uranium atoms .
Nuclear power plants
In nuclear power plants, the heat released in the nuclear fission reaction of uranium is used to heat water in a boiler until it reaches its boiling point. The steam will be responsible for moving the turbogenerator, completing the process of transforming nuclear energy into electrical energy.
Advantages and disadvantages of nuclear energy
Advantages of nuclear energy
– does not use fossil fuels;
-does not generate greenhouse gases;
– it is not necessary to flood vast areas, as in the construction of hydroelectric plants, which saves natural reserves, arable land and even inhabited regions;
– does not suffer from climate change;
– uranium (natural fuel used in almost all nuclear power plants) can be reprocessed and, in this way, reused;
-elements from nuclear fission (such as plutonium) can be used for other purposes.
Disadvantages of nuclear energy
-produces highly radioactive waste;
-Waste storage is complex, as it must be done in places where there is no human or nature interference, under the risk of accidents;
– plutonium has a very high toxicity, even if a very small amount is inhaled (0.00000324 grams are enough to lead a person to death from cancer);
-the nuclear reactor requires constant cooling, even when turned off; for this reason, plants are commonly built close to the sea. However, heating the region’s water has an environmental impact;
-Although rare, nuclear accidents have consequences that can extend indefinitely.
Chernobyl and Fukushima
The nuclear accidents at Chernobyl and Fukushima were the only two accidents that received the highest rating in terms of costs incurred and the number of resulting deaths.
Chernobyl
The Chernobyl nuclear accident occurred on April 26, 1986 due to an explosion, followed by a fire, which released large amounts of radioactive material into the atmosphere.
The radioactive particles spread over an area of about 150 thousand square kilometers (an area that covered much of the former Soviet Union – today belonging to Russia, Ukraine and Belarus – and some regions of Western Europe).
The effects of contamination still represent a problem for these countries today and there are regions (distant up to 180 kilometers from the accident site) that will pose a risk for thousands of years.
fukushima
The Fukushima nuclear accident happened on March 11, 2011 due to an earthquake (8.9 points on the Richter scale) that still triggered a tsunami. There was a failure in the cooling systems and consequent explosions, which led to the leakage of radioactive substances.
