The importance of nuclei
The alchemists wanted to perform transmutation, transform lead into gold. Seeking this determination, as well as obtaining an elixir that would grant eternal youth, they traveled a path of experimentation in which, until the 18th century, they left numerous discoveries for chemistry, inventing devices and perfecting laboratory techniques. What they did not know is that the transformation of lead into gold, from one element to another, is impossible by chemical methods. What they did not know is that in chemical reactions there are changes on the surface of the atoms, but never deep down, in the nucleus, which is where their identity lies. But we know that now. The identity cannot be changed without changing the core.
The nucleus of atoms was discovered in 1911. Making radioactive particles hit a thin sheet of gold, Ernest Rutherford had to propose an amazing model, which stated that matter is practically empty. He imagined that atoms have all their mass concentrated in a very small place, the nucleus, which also has a positive electric charge that is neutralized by the electrons that are there.
moving like crazy around him. We know that an atom is lead because it has a nuclear charge of 82, and it is gold when its nuclear charge is 79. Each nucleus thus houses the identity of the atom. But then we saw that the core can also be altered. In 1919 Rutherford himself was the first to convert nitrogen into oxygen by bombardment with alpha particles. He had achieved a transmutation. In short, at the beginning of the 30s of the last century, research on radioactivity and the nucleus of atoms caused a furor among physicists and chemists. Enrico Fermi used the novel neutrons (particles without electrical charge) as the ideal projectile to bombard atomic nuclei. The idea was that the nucleus could absorb the neutron, giving rise to a heavier element and becoming radioactive many times. Thus it was thought to obtain even larger atoms than uranium. But then the surprise would come. Otto Hahn and Lise Meitner were working in Berlin studying the interaction of neutrons with uranium nuclei, and when barium was found among the products of that nuclear reaction, Lise indicated that this proved that the nucleus had split in two. Incredible but true. Soon it was also discovered that in this process, which could take place in a chain, a large amount of energy was released. In December 1938, 80 years ago, they had discovered nuclear energy.
And 50 years ago today, on December 12, 1968, Spain inaugurated the first power plant that worked with nuclear energy. It was located on the banks of the Tagus, in Almonacid de Zorita (Guadalajara), and with its pressurized water reactor (PWR) it had an installed capacity of 160 MW. It worked for 38 years at full capacity, until in 2006 the definitive cessation of its activity was decreed. Today we have five nuclear power plants in operation in Spain, and in 2017 this was the second source of energy in our country (22.4%), after renewables (33.7%).