This is very clear.

Maybe not every of you understands well the concepts and terms, we use, in this conversation with you. We would avoid to confuse you and to load your memory by different “odd” things.

Nevertheless, it is necessary to explain facts; you will need to understand clearly the message of this book. We shall try to explain these odd things absolutely clearly. You can read this now. We hope that it will be useful to you. But it is also possible to come back to it when in the text of the book there will be something unfamiliar to you. Choose. Meanwhile we shall start with “trifles”.

The Atom. Once, the atom was considered the smallest particle of in our universe. The name ”atom” of this particle means “indivisible” in the Greek language Later it was possible to divide the atom in smaller “indivisible” parts. The atom consists of a nucleus and electrons. The nucleus represents a kind of centre of a “nuclear system”, around of which very small particles, the electrons, move on orbits. It resembles somewhat to the solar system: the nucleus plays the part of the Sun, and the electrons, that of planets. One speaks even of the planetary structure of the atom.

The Electrons are very small particles comparing to the nucleus. In an atom of hydrogen, the weight of an electron is almost 2.000 times smaller than the weight of a nucleus. This particle has a negative charge, identical for all electrons, which has been accepted as the unit for an electric charge.

The Nucleus of the atom is very heavy in comparison with its electrons. When speaking about “nuclear weight”, one means the weight of the nucleus. The nucleus of an atom has a positive electric charge equal in size to the charge of all its electrons. Therefore, the atom appears as neutral, which means that his full charge is equal to zero.

The structure of a nucleus. The nucleus of the simplest element, hydrogen (we shall designate it H 1), consists of one single particle, a proton, which has a positive charge equal on size to that of one electron. Hydrogen has one electron and one proton. In heavier atoms, there are many electrons. Their nucleus should contain as many protons. But in a nucleus of such atoms, besides protons, there are also neutrons. These are particles with the same weight as protons, but with no electric charge. For example, in natural Uranium, the nuclear weight is 238, which means that his atom is 238 times heavier than an atom of hydrogen. Its symbol is U-238. It has 92 electrons and as many protons. And the missing quantity of nuclear weight is made up by neutrons, which amount to 238-92=146.

The neutron – it is not such an important particle with no charge of its own. But is very artful: it can leave the nucleus or accept in its company additional neutrons, which have left other nucleus. Such atoms with “non-standard” quantities of neutrons, turns to be the isotopes given atoms.

The isotope is an atom where the quantity of neutrons differs from their quantity in its normal condition. In such an isotope, the number of protons and of electrons remains the same, but the nuclear weight because of the new neutrons, differs. Uranium-238, which has lost three neutrons, can turn to an isotope Uranium - 235, which form the basis of the fuel of a nuclear reactor. The isotopes differ in stability and can spontaneously release or absorb neutrons.

The Isotopes of Hydrogen and heavy water. Usual water represents a chemical compound composed by two atoms of hydrogen and one atom of oxygen. We already spoke about hydrogen (H-1), but there exist also isotopes of hydrogen: Deuterium (H-2) and Tritium (H-3). In their nucleus, they possess respectively one and two neutrons. Therefore, their nuclear weight is not one, but two and three respectively. These isotopes are unstable and can spontaneously break up. But in water basins of the Earth, due to the energy of solar rays, a certain quantity of isotopes of hydrogen is constantly formed, and some balance in their concentration is established. These isotopes exist always in water, though in very small concentration. On their basis, there are also molecules of heavy water, formed by the H-1 isotope deuterium and oxygen. Such heavy water is also used in the Canadian reactor “Candu”. It is necessary to note, that contrary to usual water, heavy water is a dangerous poison.

Fast and thermal neutrons. When the neutron leaves the nucleus, it “hastens” to leave him, as fast as possible. Its speed can be very fast. At such speed, it manages to fly unnoticed by the nucleus of other atoms. Such neutrons are referred to fast neutrons. If we need to catch neutrons in order to let them be swallowed by other nucleus, it will be almost impossible with fast neutrons, the most part of them simply flying by. It certainly is possible “to catch and return them back”, or to use them for any other purposes. But it is very difficult. It is only possible in so-called “fast neutron reactors”. In other reactors, it is necessary “to slow down” fast neutrons, to such speeds where it is difficult for them to evade a nucleus on its way. For these purpose, moderators substances are used.

Moderator substance, at passage through which are substances where the speed of neutrons slowed down when passing through. Atoms of moderators act like playing the role of supernumeraries on a movie platform. They crowd the scene, constantly crossing the way of “hastening” neutrons and compel them to reduce their speed. Such moderators can be water, heavy water, and graphite. Neutrons, whose speed is reduced to the state allowing them to be absorbed by nucleus meeting by them on their way, are referred to, as slow or thermal neutrons. The overwhelming majority of nuclear reactors work today with such neutrons. Therefore, for such reactors neutrons moderators are an important part.

Splitting of nucleus. Nucleuses of heavy elements possess the ability to be split, that is to form “splinters”, being nucleus of lighter elements. Such splitting occurs under the action of a neutron striking a nucleus. At division of a heavy nucleus into splinters releases energy, this is called atomic energy.

Atomic energy. During the splitting of nucleus of heavy elements, for example Uranium or Plutonium by the nuclear reaction occurring in a reactor, a great quantity of energy, which can be named atomic, or nuclear energy is produced.

Nuclear synthesis. With light nucleus, something opposite can happen. Light nucleus such as hydrogen, its isotopes and lithium produce huge energy not by splitting (there is no mean to split further), but by their merging or synthesis. This phenomenon is also referred to as nuclear synthesis. The energy produced by it, is thousand times greater, than by splitting heavy nucleus. Due to such a process occurring inside it, the Sun manages to maintain such a high temperature that the warmth of its beams reaches us. On the Sun this process proceeds at “star” temperatures reaching hundred millions degrees. On Earth, such conditions were created only in the mass of hydrogen of thermonuclear bomb. But there is a doubt that industrial processes can proceed at so high temperatures.

Cold nuclear synthesis. Many scientists today declare that this process is possible. Even the creation of installations, producing a high output of energy, which they explain by cold synthesis. For this, water in which as you already know, is some Deuterium can provide a reaction of synthesis, which is used. It is extremely important that at reaction of synthesis, no harmful substances to humans and to nature are formed. The existing unlimited resources of isotopes of hydrogen in the water basins of the Earth, could transform cold synthesis into a practically inexhaustible energy source for Humankind. Give God that this would be the truth!

Chain reaction. In a given volume of nuclear fuel, a certain quantity of neutrons takes off from some nucleus. Part of them is absorbed by other nucleus. These «excited» nucleuses, indignant because of the intrusion by uninvited visitors, can throw out one or several neutrons. Only part of those can be absorbed by other nucleus, which again can release a certain quantity of neutrons. The most important question is whether the stream of moving neutrons will fade away or will made multiple copies. If the stream remains constant, it is already a chain reaction. If it starts to expand and there is no way to stop this expansion, there is an explosion. Such a process of an unlimited increase of the intensity of a neutron stream also occurs in nuclear bomb. But not only there. The Chernobyl reactor could also not stop the process of “expansion”, and there was an explosion! In a normal operating mode of a nuclear reactor, it is necessary to keep the stream of neutrons in a balance. For this purpose in reactors, various systems of regulation and protection are installed. With their help, a certain average condition between “diminishing” stream and mode of nuclear bomb is maintained. It is possible to feel the close “related communication” of a nuclear reactor and a nuclear explosive. These “relatives” are only divides only by thin wall in a public apartment. Balancing on this sharp edge is also the main task of “peaceful” atomic lobbyists. This problem not simple, and sometimes it is impossible to solve. In fact, they also force us to balance together with them. And the price in this risky game is our lives!

MOX Fuel (mix oxide) is a fuel for nuclear reactors, representing a mix of plutonium and uranium. It is used more and more in the French nuclear reactors (PWR).

Types of reactors. Nuclear reactors can be divided into two groups: reactors with thermal neutrons and reactors with fast neutrons. The overwhelming majority of reactors concern to the first group. In this group, reactors can be divided into subgroups according to the form of moderator and the heat-carrier.

The heat-carrier is the substance, which transports the heat produced by the fuel elements. It can be water, carbonic gas, helium and even liquid metal natrium (in reactors on fast neutrons). We shall concentrate only on the basic types of reactors.

Reactor such as WWER. Its name means “pressurized waterpower reactor”. Water is both the moderator and the heat-carrier. This type of reactor, with various modifications, (boiling water reactor, BWR) is the most widespread in the world. One part of the Russian reactors also concerns to this type.

Reactor such as RBMK - uranium-graphite reactors. The moderator in it is graphite which units fill totally the interior of reactor, except for vertical channels, where the heat producing fuel (TVS) is placed, and through which the heat carrying water passes, producing heat. Such reactors are constructed only in Russia. Chernobyl reactors concern this type.

Reactor such as BN - the reactor on fast neutrons. The heat-carrier in it is liquid metal natrium. The specificity of this type of reactor is that it produces significant amounts of Plutonium, which can be used, as nuclear fuel for other reactors, and as material for nuclear bombs. Such reactors are named “fast breeder reactors”.

Canadian reactor “Candu” differs from the reactor type WWER mainly in that “heavy water” and not usual water is used.

Radioactivity - spontaneous transformation (decay) of atomic nucleus of some elements (radionuclides), accompanied with radiation.

Radionuclides - unstable isotopes in which spontaneous transformations occur, accompanied with radiation.

Physical half-life period - time in which half of all radionuclides of a given type decay. During the following same period, the half of the rest will decay. Half-life period (HLP) is different for different radionuclides. For Iodine - 131, which has been thrown out from the Chernobyl reactor, HLP=8 day. This means, that its dangerous influence lasts about two months, during which the intensity of its radiation decreases almost in 200 times. With Caesium - 137, one of the basic radionuclides, released by the explosion of the reactor, the situation is much worse. It has a HLP=30 of years. Therefore, hundreds of years are necessary before the decay of this radionuclide. And one more released element, Plutonium - 239, is one of the most dangerous, its HLP=24.000 years. It is even called “eternal” radionuclide.

Ionising radiation is the radiation (radioactive, x-ray, etc.) which influence on substances (the body of the person, animal, plant) results in the decomposition of molecules in ions (positively and negatively charged parts of molecules).

Irradiation. The influence of ionising radiation is divided in external and internal.

External irradiation - the irradiation of body from external sources of radiation. This kind of the irradiation influences organisms present in radiocontaminated territories or near to other sources of radiation.

Internal irradiation is the irradiation from sources, which are incorporated inside of the body of the person. These sources enter the organism through respiratory ways (with dust in air) and with foodstuffs contaminated by radionuclides. The internal irradiation is especially dangerous for the organism, as it continues to operate irrespective of the place, “clean” or “dirty” where a person or other organisms live. There exist special products, or food additives (pectin), which accelerate the elimination of radionuclides from the organism.

The absorbed dose is the quantity of energy received by the organism during irradiation (external and internal).

The Roentgen is a unit of measurement of the absorbed dose.

The REM is the biological equivalent of the roentgen, the unit of measurement of an equivalent dose that is taking into account different influences of a same irradiation in different kinds of organism.

The dose limit is the highest permissible value of the absorbed doze for one calendar year.

Allowable irradiation of the population - 0,5 Rem/year.

Allowable irradiation of the personnel of nuclear installations - 5 Rem/year.

Allowable emergency irradiation of the population - 10 Rem (during the same period).

Allowable emergency irradiation of the personnel - 25 Rem (during the same period). This dose has been accepted as maximum permissible dose for the participants in the work on liquidation of the consequences of Chernobyl accident.

IAEA is the International Agency on the Atomic Energy. The headquarters of this organization is in the capital of Austria, Vienna. IAEA is an organisation of the Organization of the United Nations accountable directly to the UN Security Council carries out the control over the NPP worldwide and carries out the account of their construction and conditions of operation.

NPP – Nuclear Power Plant.

NHPP – nuclear heat and power plant, this is a nuclear power plant, producing electric power and heat or only heat.

Дата добавления: 2015-11-14