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You attain stability in nuclear fission by exactly balancing the number of fission events with the number of neutrons that go on to produce fission events. This is done by using a moderator that responds to temperature in such a way as to self regulate the reaction.
In a typical light water moderated reactor, the density of the water affects how it moderates the neutrons. As temperature goes up, density goes down, which decreases moderation, which slow the reaction. Density is actually a process of the number of voids in the water, voids where there is no water, i.e. no moderation. Even though pressure increases in this case, the void density decreases, making this a self regulating response.
If the turbine, for instance, were to suddenly demand more steam, the reactor coolant would drop in temperature, decreasing the number of voids, and increasing reactivity, which would bring the reactor up in power to match the load change.
If, on the other hand, a depressurization event were to occur, ignoring, for now, the control rods, the coolant would flash to steam, and the voids would essentially drastically increase. Moderation would plummet, reactivity would go negative, and the reactor would go sub critical, shutting down the reactor, essentially, in the blink of an eye.
Back to the control rods. They provide a gross reactivity control, and are used to startup, shutdown, and trim the reactor for changing conditions. They also respond in abnormal conditions, providing emergency shutdown when needed, but that was not really the question.
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How does nuclear fusion different to nuclear fission?
Fastern your seatbelt. We've got some ground to cover. But it won't be too difficult to grasp the fundamentals. In either fission or fussion, we are taking about nuclear processes, i.e., the physics of nuclear structure and construction/destruction of that nucleus. The big difference is fusion is the "building" of atomic nuclei, and fission is the "breaking" or "splitting" of atomic nuclei. Fusion is the bonding of atomic nuclei or nuclear particles (nucleons - protons and neutrons) to make "bigger" or "heavier" atomic nuclei. Fission, on the other hand is the splitting of the atom. As the atoms fuse or split they release energy. Lots of it. And most of it is heat energy. In nuclear weapons, the energy is released "all at once" to create a blast. If the energy is released in a "controlled" way, we can release heat at a "useable" rate and apply it to boiling water to make steam. In fusion, protons or neutrons or the nuclei of atoms are forced together and are fused to make a new atomic nucleus. The release of lots and lots of energy accompanies this reaction. That's what powers stars. Currently we can't really do any fusion reactions to make useful power. There are a few agencies working on fusion devices, but the high temperatures required to attain fusion require very special materials and controls. The current "state of the art" fusion facility is the International Thermonuclear Experimental Reactor (and a link is provided). Fusion is unlikely to become a useful source of power for many years. But what about fission? Nuclear fission involves the splitting of large atoms, usually uranium (or sometimes plutonium). When large atoms fission they produce two smaller atoms or fission fragments (and a couple of neutrons and lots of energy). The total mass of the products is less than the mass of the original atom. This mass difference is turned into energy in accordance with the Einstein equation E=mc2. Most of the energy appears in the recoil of the fission fragments, and the heat that is generated is considerable. It is that heat that we capture to turn water into steam to generate electricity. Nuclear Fission: Basics When a nucleus fissions, it splits into several smaller fragments. These fragments, or fission products, are about equal to half the original mass. Two or three neutrons are also emitted. Nuclear Fission The sum of the masses of these fragments is less than the original mass. This 'missing' mass (about 0.1 percent of the original mass) has been converted into energy according to Einstein's equation. Fission can occur when a nucleus of a heavy atom captures a neutron, or it can happen spontaneously. = Nuclear Fusion = Nuclear Fusion Nuclear energy can also be released by fusion of two light elements (elements with low atomic numbers). The power that fuels the sun and the stars is nuclear fusion. In a hydrogen bomb, two isotopes of hydrogen, deuterium and tritium are fused to form a nucleus of helium and a neutron. This fusion releases 17.6 MeV of energy. Unlike nuclear fission, there is no limit on the amount of the fusion that can occur. Nuclear fusion is taking two different atoms and combining them in to one atom, while nuclear fission takes one atom and seperates it into two atoms. Fission and fusion Fission is splitting the atom, and fusion is combining two or more atoms into one atom.
What atoms can form an ion?
an atom which readily losses or gains electrons to attain stability forms an ion.
Why the metal is very reactive?
Metals , generally, have electronic configuration: with outermost electron having 1,2 or 3. Since, they can easily attain noble gas configuration to attain stability; they readily loose electron.
Compare and contrast nuclear fission and nuclear fusion?
The process of combining two nuclei to form a heavier nucleus and thereby releasing energy is nuclear fusion. When a neutron strikes an atom of uranium-235, the atom captures the neutron, becoming an atom of uranium-236 with an excited nucleus. The U-236 nucleus vibrates rapidly and cannot hold itself together; it splits into several pieces (smaller atoms, free neutrons, etc.) in a process called nuclear fission (fission means "division"), releasing an enormous amount of heat energy and gamma rays.
Why do elements need to attain a noble gas configuration?
All the elements in their normal state are reactive and unstable. In order to attain stability i.e. a state of minimum energy, they tend to form ions by loosing or gaining electrons. By doing so, they achieve stable electronic configuration or noble gas configuration. However, some elements do not form ions. Instead of that, two such atoms share electrons with each other and achieve this noble gas configuration. At the end, the main reason for attaining a noble gas configuration is to attain max. stability and min. energy.
What does group 18 become when it is attain in the periodic table?
Group-18 belongs to inert elements. The elements attain stability.
What are the nuclear transformations to be exercised by a nuclide to attain stability?
AnswerNuclear transformation is what happens to an unstable atom nucleus when exercising changes to attain stability. The stability of a nucleus depends on the ratio of neutrons to protons in this nucleus and on the absolute number of protons that should not exceed certain limit. For a nucleus with neutron/proton ratio higherthan the corresponding stability ratio, two nuclear transformations may occur to decrease the ratio in the nucleus in order to reach stability:neutron transformation to proton plus electron where the proton remains in the nucleus and the electron is emitted from the nucleus as beta radiationemitting neutron from the nucleus as neutron radiation (this transformation is relatively rare. Example of this transformation is the unstable Krypton-87For a nucleus with neutron/proton ratio lower than the corresponding stability ratio, two nuclear transformations may occur to increase the ratio in the nucleus in order to reach stability:proton transformation to neutron plus positron where the neutron remains in the nucleus and the positron is emitted from the nucleus as positive beta radiationproton attraction of one electron from the nearest orbit to the nucleus to form neutron that remains in the nucleus.For an unstable nucleus with with number of protons exceeding the stability limit, it may reach stability with one or more of the above four nuclear transformations and/or by:fission (or splitting) of the nucleus into two or more smaller nuclei (called fragments) with emission of one or more neutrons (as the spontaneous fission of some heavy nuclei).
How does nuclear fusion different to nuclear fission?
Fastern your seatbelt. We've got some ground to cover. But it won't be too difficult to grasp the fundamentals. In either fission or fussion, we are taking about nuclear processes, i.e., the physics of nuclear structure and construction/destruction of that nucleus. The big difference is fusion is the "building" of atomic nuclei, and fission is the "breaking" or "splitting" of atomic nuclei. Fusion is the bonding of atomic nuclei or nuclear particles (nucleons - protons and neutrons) to make "bigger" or "heavier" atomic nuclei. Fission, on the other hand is the splitting of the atom. As the atoms fuse or split they release energy. Lots of it. And most of it is heat energy. In nuclear weapons, the energy is released "all at once" to create a blast. If the energy is released in a "controlled" way, we can release heat at a "useable" rate and apply it to boiling water to make steam. In fusion, protons or neutrons or the nuclei of atoms are forced together and are fused to make a new atomic nucleus. The release of lots and lots of energy accompanies this reaction. That's what powers stars. Currently we can't really do any fusion reactions to make useful power. There are a few agencies working on fusion devices, but the high temperatures required to attain fusion require very special materials and controls. The current "state of the art" fusion facility is the International Thermonuclear Experimental Reactor (and a link is provided). Fusion is unlikely to become a useful source of power for many years. But what about fission? Nuclear fission involves the splitting of large atoms, usually uranium (or sometimes plutonium). When large atoms fission they produce two smaller atoms or fission fragments (and a couple of neutrons and lots of energy). The total mass of the products is less than the mass of the original atom. This mass difference is turned into energy in accordance with the Einstein equation E=mc2. Most of the energy appears in the recoil of the fission fragments, and the heat that is generated is considerable. It is that heat that we capture to turn water into steam to generate electricity. Nuclear Fission: Basics When a nucleus fissions, it splits into several smaller fragments. These fragments, or fission products, are about equal to half the original mass. Two or three neutrons are also emitted. Nuclear Fission The sum of the masses of these fragments is less than the original mass. This 'missing' mass (about 0.1 percent of the original mass) has been converted into energy according to Einstein's equation. Fission can occur when a nucleus of a heavy atom captures a neutron, or it can happen spontaneously. = Nuclear Fusion = Nuclear Fusion Nuclear energy can also be released by fusion of two light elements (elements with low atomic numbers). The power that fuels the sun and the stars is nuclear fusion. In a hydrogen bomb, two isotopes of hydrogen, deuterium and tritium are fused to form a nucleus of helium and a neutron. This fusion releases 17.6 MeV of energy. Unlike nuclear fission, there is no limit on the amount of the fusion that can occur. Nuclear fusion is taking two different atoms and combining them in to one atom, while nuclear fission takes one atom and seperates it into two atoms. Fission and fusion Fission is splitting the atom, and fusion is combining two or more atoms into one atom.
How are ionic bonds and covalent bonds solve the problem of achieving stability in atoms?
according to octect rule , an atom need to complete the octect to attain stability . The atoms forms ionicbond by donate or accept electrons . And also atoms forms covalent bond by shearing oe electron . The two types bonds are help to attain stability
What atoms can form an ion?
an atom which readily losses or gains electrons to attain stability forms an ion.
Why the metal is very reactive?
Metals , generally, have electronic configuration: with outermost electron having 1,2 or 3. Since, they can easily attain noble gas configuration to attain stability; they readily loose electron.
What is the reason for chemical bond?
The basic reason for chemical bonding among elements is to attain the maximum possible stability. For instance we make relationship bonds among nations to remain in peace or to attain stability!!
Compare and contrast nuclear fission and nuclear fusion?
The process of combining two nuclei to form a heavier nucleus and thereby releasing energy is nuclear fusion. When a neutron strikes an atom of uranium-235, the atom captures the neutron, becoming an atom of uranium-236 with an excited nucleus. The U-236 nucleus vibrates rapidly and cannot hold itself together; it splits into several pieces (smaller atoms, free neutrons, etc.) in a process called nuclear fission (fission means "division"), releasing an enormous amount of heat energy and gamma rays.
Self-actualization is the process through which people attain their?
full potential
Explain the process by which a territory became a state?
The process by which the United States territories attain full statehood is, at best, an inexact art.
Why do elements need to attain a noble gas configuration?
All the elements in their normal state are reactive and unstable. In order to attain stability i.e. a state of minimum energy, they tend to form ions by loosing or gaining electrons. By doing so, they achieve stable electronic configuration or noble gas configuration. However, some elements do not form ions. Instead of that, two such atoms share electrons with each other and achieve this noble gas configuration. At the end, the main reason for attaining a noble gas configuration is to attain max. stability and min. energy.
How and why element combine?
elements combine to attain more stability, generally by attaining the electronic configuration of the nearest noble gases. they do so by donating electrons, accepting electrons or by sharing electrons
