spikey_richie
04-24-2007, 05:51 AM
I snagged this via Google Translate:
Zaragoza City of the Knowledge. ZIVIS
Zivis: First Great Citizen Supercomputador >>Aplicaciones >> the Fusion
The obtaining of energy is one of the main problems to which the world entrenta nowadays. The consumption was increased enormously during the past century XX and everything indicates that in this century it will continue growing. Nevertheless, the main main power plants that we used, the fossil fuels, will begin to be scarce and in addition its indiscriminate use is contributing of decisive way to the climatic change. The challenge consists therefore of finding other power plants that are able to face that increase in the demand and which they respect environment. The fusion appears like one of the great alternatives, but its enormous technical complexity does necessary to develop projects as ZIVIS for its study. TYPES DE ENERGY FUENTES
In order to resolve the problem of the power plants, one has been going away proposing different options for some time. On the one hand we found the energies renewable, that they present/display like better endorsement the respect to environment, factor that in the present circumstances has become very important. Among them they emphasize Aeolian, hydraulic, geothermal, mareomotriz energy solar, or biomass. Nevertheless, the two first, for example, have the disadvantage of their great dependency with the meteorological conditionses. Another great alternative has been, for half century, the nuclear energy based on the fission. Able to generate great amounts of energy by itself, it has the disadvantage of the radioactive remainders that produces, that lasts during long periods of time. Before this routes of investigation of new sources are opened: the great trick would be the fusion since it combines great productivity, abundance of raw material and respect to environment. But the technology to be able to use it still is being developed.
WHAT IS THE FUSION?
The nuclear fusion consists of uniting two light nuclei to form one heavier, freeing energy in the process. Nevertheless the nuclei are loaded positively and all we know that the loads of he himself sign are repelled. Then how is possible that two nuclei are united if they are repelled mutually? Other fundamental forces exist, in this case the nuclear force hard, that attracts protons and neutrons to each other (the constituent elements of the atomic nucleus). But this force is of very short reach, that is to say, that the nuclei will have to be very together so that it can feel, so still we need to solve the problem to approach much two elements that are repelled. This is obtained giving sufficient energy them: that the nuclei are moving so quickly that the electromagnetic force of repulsion among them is not able to prevent that they approach much. For it the temperature is increased of the gas, that when being constituted by loaded particles (nuclei and electrons) gives rise to a plasma. This temperature is of tens or even of hundreds of million degrees. But not only this is necessary, in addition it is essential that the number of encounter between nuclei is great, and it is obtained increasing the density of the plasma. In these circumstances the fusion could be carried out and, if they are able to maintain during sufficient time, extract energy of this process. But this generates a technical problem to us how we maintain during the necessary time a plasma of sufficient density to so high temperature? This one is the problem of the confinement.
CONFINEMENT
No container can contain a plasma to so high temperatures: the walls would be deteriorated immediately and would emit impurities to the plasma, which would be far from the necessary conditions for the fusion. In order to solve this problem we could pay attention to how it has solved it the nature. The nuclear fusion is carried out of natural way inside stars. In this case, it is the gravity the one that is in charge to create the necessary conditions inside the star and is a system that obvious maintains them during long time. Nevertheless it is not a viable solution to make it in the Earth. We have to look for another method, and the most advanced at the moment it is the magnetic confinement. This one is based on which, in the presence of a magnetic field, the loaded particles follow the direction of the lines of field (describing helices around them). Therefore, if we created a magnetic field whose lines are contained in a toroidal region (with life-guard form) particles of the plasma will stay as well in this region. Thus one is able to have the plasma to the high temperatures that are necessary without it is in contact with the enemy with the materials of the housing of the reactor. But there are other factors to consider that harm the confinement of the plasma: the particles of the plasma interact among them. Thus, after a collision they can leave this region and hit the walls of the reactor. In addition to the electric field, the curvature and the inhomogeneidades in the magnetic field make that the plasma tends to escape of the zone of confinement, in a called phenomenon transport. In the study of the transport, that involves a great number of particles (trillones by each square meter) is where the simulations by computer enter. In order to carry out them, a great power of calculation is necessary, reason why project ZIVIS has been created. In him, we calculated the trajectories of million ions inside the plasma, and studied the behavior of these particles based on the excellent parameters of the plasma. One of the amounts to measure will be the time of confinement of the plasma in certain conditions of temperature and density, that is one of the magnitudes to optimize.
FUELS AND OBTAINING OF THE ENERGY
Until now we have only said that the fusion could be carried out with slight elements, but which have seted out to use? It is not tried to copy the complicated cycles of reactions that occur inside stars, as the chain proton-proton or the cycle of carbon-nitrogen-oxygen (the this last most important one in stars more massive than the Sun). In the reactors that consider at the moment it tries to react deuterium with tritium to give like result helium-4 and a neutron of high energy, that most of takes the energy of the reaction. This it is the process: D T - > 4He n. The deuterium and the tritium are isotopes of hydrogen. First one is in the nature: he is present in the water in a proportion of about 30 grams by each cubic meter of water. The tritium nevertheless is not in the nature and is necessary to obtain it from lithium. He is radioactive, but it has a short average life and in addition it will be obtained directly in the own plant of a future reactor of fusion. The products of the reaction are the helium-4 and neutrons of high energy, that to the being neutral no longer stay in the region of the magnetic field and they escape towards the outside of the reactor. For that reason the reactor with a structure is surrounded by a material with lithium the sufficiently heavy thing like restraining neutrons. In addition the lithium reacts with neutrons to give tritium, that is reused in the reactor. As the process releases to energy the wall is warmed up and this heat is used to produce water steam and to generate electricity of conventional way.
The option studies to use other processes like reacting deuterium with deuterium, obtaining helium-3 and a neutron or tritium and a proton. Of this form the necessity would be eliminated to obtain tritium and it would as well be avoided to work with this radioactive substance. Finally also the reaction between deuterium and helium-3 is very interesting, that a proton gives rise to helium-4 and, although has the disadvantage of the little amount of present Earth helium-3.
Unlike the nuclear reactors based on the fission, a future reactor of fusion would not have the disadvantage of the long life of the radioactive substances since while it was in single operation it would use tritium as radioactive element and would take place inside the plant. In addition, the elements that have been able to activate in the walls of the reactor will have let be dangerous in a period of about 100 years after the desmantelación of the reactor.
All the saying previously causes that the fusion like one of the most important future power plants is considered that allow to finish with the present dependency of fossil fuels, although still it is being investigated to solve the technical problems that there are to confront for being able to use it. In particular, the study of the transport by means of numerical simulations by computer has special importance like which they will be made in ZIVIS.
Zaragoza City of the Knowledge. ZIVIS
Zivis: First Great Citizen Supercomputador >>Aplicaciones >> the Fusion
The obtaining of energy is one of the main problems to which the world entrenta nowadays. The consumption was increased enormously during the past century XX and everything indicates that in this century it will continue growing. Nevertheless, the main main power plants that we used, the fossil fuels, will begin to be scarce and in addition its indiscriminate use is contributing of decisive way to the climatic change. The challenge consists therefore of finding other power plants that are able to face that increase in the demand and which they respect environment. The fusion appears like one of the great alternatives, but its enormous technical complexity does necessary to develop projects as ZIVIS for its study. TYPES DE ENERGY FUENTES
In order to resolve the problem of the power plants, one has been going away proposing different options for some time. On the one hand we found the energies renewable, that they present/display like better endorsement the respect to environment, factor that in the present circumstances has become very important. Among them they emphasize Aeolian, hydraulic, geothermal, mareomotriz energy solar, or biomass. Nevertheless, the two first, for example, have the disadvantage of their great dependency with the meteorological conditionses. Another great alternative has been, for half century, the nuclear energy based on the fission. Able to generate great amounts of energy by itself, it has the disadvantage of the radioactive remainders that produces, that lasts during long periods of time. Before this routes of investigation of new sources are opened: the great trick would be the fusion since it combines great productivity, abundance of raw material and respect to environment. But the technology to be able to use it still is being developed.
WHAT IS THE FUSION?
The nuclear fusion consists of uniting two light nuclei to form one heavier, freeing energy in the process. Nevertheless the nuclei are loaded positively and all we know that the loads of he himself sign are repelled. Then how is possible that two nuclei are united if they are repelled mutually? Other fundamental forces exist, in this case the nuclear force hard, that attracts protons and neutrons to each other (the constituent elements of the atomic nucleus). But this force is of very short reach, that is to say, that the nuclei will have to be very together so that it can feel, so still we need to solve the problem to approach much two elements that are repelled. This is obtained giving sufficient energy them: that the nuclei are moving so quickly that the electromagnetic force of repulsion among them is not able to prevent that they approach much. For it the temperature is increased of the gas, that when being constituted by loaded particles (nuclei and electrons) gives rise to a plasma. This temperature is of tens or even of hundreds of million degrees. But not only this is necessary, in addition it is essential that the number of encounter between nuclei is great, and it is obtained increasing the density of the plasma. In these circumstances the fusion could be carried out and, if they are able to maintain during sufficient time, extract energy of this process. But this generates a technical problem to us how we maintain during the necessary time a plasma of sufficient density to so high temperature? This one is the problem of the confinement.
CONFINEMENT
No container can contain a plasma to so high temperatures: the walls would be deteriorated immediately and would emit impurities to the plasma, which would be far from the necessary conditions for the fusion. In order to solve this problem we could pay attention to how it has solved it the nature. The nuclear fusion is carried out of natural way inside stars. In this case, it is the gravity the one that is in charge to create the necessary conditions inside the star and is a system that obvious maintains them during long time. Nevertheless it is not a viable solution to make it in the Earth. We have to look for another method, and the most advanced at the moment it is the magnetic confinement. This one is based on which, in the presence of a magnetic field, the loaded particles follow the direction of the lines of field (describing helices around them). Therefore, if we created a magnetic field whose lines are contained in a toroidal region (with life-guard form) particles of the plasma will stay as well in this region. Thus one is able to have the plasma to the high temperatures that are necessary without it is in contact with the enemy with the materials of the housing of the reactor. But there are other factors to consider that harm the confinement of the plasma: the particles of the plasma interact among them. Thus, after a collision they can leave this region and hit the walls of the reactor. In addition to the electric field, the curvature and the inhomogeneidades in the magnetic field make that the plasma tends to escape of the zone of confinement, in a called phenomenon transport. In the study of the transport, that involves a great number of particles (trillones by each square meter) is where the simulations by computer enter. In order to carry out them, a great power of calculation is necessary, reason why project ZIVIS has been created. In him, we calculated the trajectories of million ions inside the plasma, and studied the behavior of these particles based on the excellent parameters of the plasma. One of the amounts to measure will be the time of confinement of the plasma in certain conditions of temperature and density, that is one of the magnitudes to optimize.
FUELS AND OBTAINING OF THE ENERGY
Until now we have only said that the fusion could be carried out with slight elements, but which have seted out to use? It is not tried to copy the complicated cycles of reactions that occur inside stars, as the chain proton-proton or the cycle of carbon-nitrogen-oxygen (the this last most important one in stars more massive than the Sun). In the reactors that consider at the moment it tries to react deuterium with tritium to give like result helium-4 and a neutron of high energy, that most of takes the energy of the reaction. This it is the process: D T - > 4He n. The deuterium and the tritium are isotopes of hydrogen. First one is in the nature: he is present in the water in a proportion of about 30 grams by each cubic meter of water. The tritium nevertheless is not in the nature and is necessary to obtain it from lithium. He is radioactive, but it has a short average life and in addition it will be obtained directly in the own plant of a future reactor of fusion. The products of the reaction are the helium-4 and neutrons of high energy, that to the being neutral no longer stay in the region of the magnetic field and they escape towards the outside of the reactor. For that reason the reactor with a structure is surrounded by a material with lithium the sufficiently heavy thing like restraining neutrons. In addition the lithium reacts with neutrons to give tritium, that is reused in the reactor. As the process releases to energy the wall is warmed up and this heat is used to produce water steam and to generate electricity of conventional way.
The option studies to use other processes like reacting deuterium with deuterium, obtaining helium-3 and a neutron or tritium and a proton. Of this form the necessity would be eliminated to obtain tritium and it would as well be avoided to work with this radioactive substance. Finally also the reaction between deuterium and helium-3 is very interesting, that a proton gives rise to helium-4 and, although has the disadvantage of the little amount of present Earth helium-3.
Unlike the nuclear reactors based on the fission, a future reactor of fusion would not have the disadvantage of the long life of the radioactive substances since while it was in single operation it would use tritium as radioactive element and would take place inside the plant. In addition, the elements that have been able to activate in the walls of the reactor will have let be dangerous in a period of about 100 years after the desmantelación of the reactor.
All the saying previously causes that the fusion like one of the most important future power plants is considered that allow to finish with the present dependency of fossil fuels, although still it is being investigated to solve the technical problems that there are to confront for being able to use it. In particular, the study of the transport by means of numerical simulations by computer has special importance like which they will be made in ZIVIS.