The moderator is a component that is part of nuclear reactors. It is located in the reactor core. The function of the moderator is to reduce the speed of neutrons in nuclear fission reactions.
During fission nuclear reactions, neutrons collide with fissile atoms (uranium and plutonium) present in the nuclear fuel causing fission. With each fission reaction, one or two neutrons are released at high speed.
The objective to maintain a chain fission reaction is that these neutrons hit other fissile atoms but at such a speed it is very difficult. The objective of…
Nuclear fission is the physical-chemical reaction through which the nucleus of an atom is split. In the main interest of the fission reactions is that by this operation a large amount of energy is obtained. Nuclear energy is the energy contained in the nucleus of an atom and the energy that is obtained is thermal energy, energy in the form of heat.
The other form of exploitation is through nuclear fusion reactions. In this case, the process is inverse, fusing two different nuclei forming a single atomic nucleus.
After the fission of the atomic nucleus we obtain…
Isotopes are atoms whose nuclei have the same number of protons but different numbers of neutrons. Not all atoms of the same element are identical and each of these varieties corresponds to a different isotope.
Each isotope of the same element have the same atomic number (Z) but each has a different mass number (A). The atomic number is the number of protons in the atomic nucleus of the atom. The mass number is the sum of neutrons and protons of the core. This means that different isotopes of the same atom differ from each other only by the number of neutrons.
The items that can…
A nuclear reactor is a facility capable of initiating, controlling and maintaining nuclear reactions (usually nuclear fission) in chain that occur in the core of this installation.
The composition of the nuclear reactor is formed by the nuclear fuel, the refrigerant, the control elements, the structural materials and, in the case of a nuclear reactor, the nuclear moderator.
To build a nuclear reactor it is necessary to have enough nuclear fuel, which we call critical mass. Having enough critical mass means having enough fissile…
The basis of everything related to nuclear energy lies in the atom, since nuclear technology is based on the use of the internal energy contained in atoms. For this reason, to understand how nuclear reactions occur (nuclear fission or nuclear fusion) it is useful to understand how an atom is structured.
An atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element.
The atom is composed of a nucleus and one or more electrons linked to the nucleus. The nucleus is made of one or more protons and, typically, a similar number of…
Uranium is the most commonly used nuclear fuel in nuclear fission reactions. It is a natural element that can be found in nature. However, in order to be able to use uranium in a nuclear reactor it must undergo some treatment.
To know the peculiarities that make uranium so different from the other substances we must first consider some basic nuclear physics. Basic physical considerations of uranium
An atom of a nucleus and electrons surrounding this nucleus. In turn, a nucleus consists of protons and neutrons. A proton has a positive charge. A neutron has no electric charge…
A neutron is a subatomic particle that is part of the atom (along with the proton and the electron). Neutrons and protons form the atomic nucleus. Neutrons have no net electric charge, unlike the proton that has a positive electric charge.
The difference in the number of neutrons in the nucleus of an atom does not imply the variation of the nature of the atom itself, but it does determine the isotope to which it is a part.
In nuclear energy the concept "uranium enrichment" refers to the alteration of the number of neutrons in the atomic nucleus in order to obtain another…
The atomic nucleus is the small central part of the atom, with positive electric charge and in which most of the mass of the atom is concentrated. It was discovered by Ernest Ruthenford in 1911. After the discovery of the neutron, in 1932, the atomic nucleus model was quickly developed by Dmitri Ivanenko and Werner Heisenberg.
The main subatomic particles of the nuclei of atoms are protons and neutrons or nucleons (except that of ordinary or own hydrogen, which contains only one proton). The same chemical element is characterized by the number of protons in the nucleus that…
The atom is a structure in which matter is organized in the physical world or in nature. The atoms form the molecules, while the atoms in turn are formed by subatomic constituents such as protons (with positive charge), neutrons (without charge) and electrons. (with negative charge).
In a graphical way, what is an atom? Let's imagine that we have a piece of iron. We split it. We still have two pieces of iron but smaller ones. We will start them again, again ... Each time we will have more smaller pieces until a moment will come, in which if we go back to…
In physics and chemistry, the atomic theory is a scientific theory of the nature of matter, which states that matter is composed of units called atoms. Atomic theory began as a philosophical concept in ancient Greece and entered the mainstream of the nineteenth century when discoveries in the field of chemistry showed that matter really behaves as if it were an atom.
The word atom originates in the atomic adjective of the ancient Greek, which means "indivisible". As explained in the history of nuclear energy. Nineteenth-century chemists began to use the term in relation to the growing…
Atomic energy comes from the atom, it is the energy that holds together neutrons and protons of the nuclei of atoms. It is also known how nuclear energy, which comes from the nucleus. The name nuclear energy is used because most of the energy of an atom resides in its nucleus.
Two parts of the atom, the nucleus and the crust are differentiated. In the cortex, an indeterminate number of electrons orbit around the nucleus. The nucleus is composed of an indeterminate number of neutrons and protons. The amount of protons in the nucleus will determine the element that the atom is treated,…
Definition of proton
A proton is a subatomic particle with positive electric charge that is inside the atomic nucleus of atoms. The number of protons in the atomic nucleus determines the atomic number of an element, as indicated in the periodic table of the elements.
The proton has charge +1 (or, alternatively, 1.602 x 10 -19 coulombs), exactly the opposite of the charge -1 that contains the electron. In mass, however, there is no competition - the mass of the proton is approximately 1,836 times greater than that of an electron.
The pressurized water nuclear reactor is the type of nuclear reactor more used worldwide in the nuclear power plants of generation of electricity. At present, there are more than 230 nuclear reactors in the world made with the pressurized water system. Also known by its abbreviations PW. Its main feature is the use of water under high pressure in the primary circuit to prevent it from boiling.
Within the naval engineering the pressurized water nuclear reactor (PWR) is widely used. In fact, this model was originally designed to be used on a nuclear submarine.
A nuclear power plant is a facility for obtaining electrical energy using nuclear energy.
Its operation is similar to that of a thermal power plant or that of a solar thermal plant: from a source of energy thermodynamics is used to obtain heat, with the heat to get steam and with the steam to drive a turbine that will generate electricity.
The difference between the different types of electrical installations is in the energy source: a nuclear power plant uses the heat released in the nuclear fission reactions of certain atoms, in a thermal power station the heat source (thermal…
A coolant in a nuclear reactor is a liquid or gaseous substance that passes through the reactor core and removes heat from the nuclear fission reaction.
In the double-circuit power reactors, the reactor coolant enters the steam generator, which produces steam that drives the turbines, and in the single-circuit reactors the coolant (steam or gas) can serve as the working fluid of the cycle of the turbine. In research (for example, materials science) and special reactors (for example, in reactors for the accumulation of radioactive isotopes) the coolant only cools the reactor, the…
We define radioactivity as the spontaneous emission of particles (alpha particles, beta particles, neutrons) or radiations (range, K capture), or both at the same time, coming from the disintegration of certain nuclides that form them, due to an arrangement in its internal structure.
Radioactive decay occurs in unstable atomic nuclei, that is, those that do not have enough binding energy to keep the nucleus together due to an excess of protons or neutrons.
Radioactivity can be natural or artificial. In natural radioactivity, the substance already has it in the natural state. In…
Alpha particles or alpha rays are a form of radiation with high ionizing, corpuscular energy and with a low penetration capacity due to the high cross section. Alpha particles consist of two protons and two neutrons joined by a strong force. From a chemical point of view, alpha particles can also be identified with the symbol 4 He ++. Along with the 3 He isotope, the alpha particles belong to the elion family. The beta decay is mediated by a weak force, while the alpha decay is mediated by a strong force. Definition of alpha particle
An alpha particle is a…
Nuclear reactors can be classified according to different criteria. One of the criteria is the purpose for which they will be used. In this regard we distinguish the types of nuclear reactors used for civilian purposes, for military purposes or for research purposes.
Civil nuclear reactors use nuclear energy to generate power for electricity; military reactors create materials that can be used in nuclear weapons such as the atomic bomb; and research nuclear reactors used to develop weapons or energy production technology, for development purposes, for nuclear physics…
To explain the history of nuclear energy we could distinguish three major stages:
- Physical and chemical scientific studies of the elements.
- The development of the nuclear bomb during World War II.
- Use of nuclear energy in the civil field.
Scientific studies cover this whole period since the first Greek philosophers began to define atoms, until the development of the first nuclear bomb. In this process, different scientists discover the presence of electrons, neutrons and protons and properties that make one atom more radioactive than another.…
The nuclear accident in Chernobyl (1986) is by far the most serious nuclear accident in the history of nuclear energy. It was classified as level 7 (severe nuclear accident) of the INES scale, the highest value. Although it is the same level at the Fukushima nuclear accident was classified, the consequences of the Chernobyl accident were still far worse.
The Chernobyl nuclear power plant is located near the town of Prypyat, 18km from the city of Chernobyl.
At the time of the Chernobyl nuclear power plant accident provided 4 reactors in operation and two more were under construction.…
Nuclear fusion is a nuclear reaction through which two light nuclei of atoms, usually hydrogen and its isotopes (deuterium and tritium), are combined forming a heavier nucleus. This binding is usually accompanied by the emission of particles (in case of deuterium nuclei one neutron is emitted). This nuclear fusion reaction releases or absorbs a lot of energy in the form of gamma rays and kinetic energy of the emitted particles.This large amount of energy transforms matter to a plasma state.
The nuclear fusion reactions can emit or absorb…