Introduction
All the things have certain energetic stage or level of static energy. They always want to find the lowest energetic stage, which is called basic stage and it is stage of highest stability. In the most of cases this includes recombination done by adding or loosing item and in all cases it leads to release extra energy - in big amounts if particles are atoms, and in huge amounts if particles are nuclei. If bonding energy of atom or nuclei increase, the stability increases too, it means that its chance to change is lower. Bonding energy ( Ev ) - added amount of energy needed to split given atom or nucleus to its items. Static energy of atom or nucleus is lower than whole static energy of its particles when they are alone. It happens because when particles are together they are in lower energetic state so they have lower energy. Bonding energy is the scale of this difference of potential energies - it is energy needed "to come back by other way" - how much it is bigger, the potential energy of atom or nucleus is lower, and their stability is bigger. Bonding energy depends on atom and nucleus.
Nuclear power
Nuclear power is strong attractive force, which holds parts of nucleus (nucleons) together and overcome electric power between protons. Its influence depends on the greatness of nucleus, because force occurs only between neighbouring nucleons. If attractive effect of nuclear power is greater, the bonding energy is also bigger (it means that more energy was released when particles have joined).
Radioactivity
Radioactivity is property of some unstable nuclei, which are spontaneous changing themselves to nuclei of other elements and emits radiation, process is known as radioactive decay. We know 3 types of radiation emitted by radioactive elements - flow of particles (called rays), flow of particles ( rays) and rays.
Radioisotope (radioactive isotope) - whatever radioactive substance (all substances are isotopes). The most of them exist always, because they have very long half-life (e.g.: uranium-238), however one, carbon-14, is still produced by cosmic radiation (background of radiation). Other radioisotopes are produced splitting of nuclei and even more are produced in research centres, where very fast particles (from protons up to uranium nuclei) hit them. They are speeded by stimulants of particles (e.g.: cyclotrons).
particles
Positive charged particles got from some radioactive nuclei ( decay). They are quite heavy (2 protons + 2 neutrons), they move quite slowly and have small penetrating power.
Penetration: several cm of air, thick sheet of paper
particles
These particles got from some radioactive nuclei by speed close to the speed of the light. We know 2 types - electrons and positrons - these have the same mass as electrons, but positive charge ( decay).
Penetration: 1m of air, 1mm of metal e.g.: copper
rays
Invisible electromagnetic waving. They had the highest penetrating power and are ordinary, but not always, emitted from radioactive nucleus after or particle.
Penetration: intensity reduced to 50% by 120m of air or 13mm layer of lead.
Radioactive decay
It is spontaneous splitting of radioactive nucleus. It emits or particles, usually followed by radiation. When nucleus release that particle, it means that nuclear decay occurs, energy is released and another nucleus (and atom) is formed. If it is also radioactive, decaying process continue, until stable (non-radioactive) atom is formed. This series of decays are called decaying queue, decaying chains, radioactive queues or transforming queues.
Half - Life of decay (change) (t1/2)
Time in which half of atoms in sample decays. It is all, what can be exactly predicted, it is impossible to predict decay of whatever simple atom, because atoms are decaying individually and randomly. Each substance have different half-life and its range is wide.
Examples: stroncium-90, 9 minutes;
uranium-238, 4.5x109 years.
Nuclear power plants
Nuclear power plants utilize radioactive materials and the process of nuclear fission to generate the heat and steam needed to run the electrical generators and produce electricity. Because nuclear plants doesn't cause the air pollution, which is associated with the burning of coal or petroleum products, this means that nuclear generating of power is considered as alternative energy source. However, the toxic nature of by-products produced by nuclear fission creates serious problems. And also the method of safely disposing of this radioactive/toxic waste haven't been found. Also volatile fission reaction can lead to a meltdown of the reactor core if the radiation is not properly controlled (e.g.: Chernobyl). Because of these serious problems, the future of nuclear power (nuclear plants ) is uncertain.
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