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Why does cadmium absorb neutrons during nuclear fission in a nuclear reactor?
Different elements absorb neutrons to different extents. The measure of this is called the neutron absorption cross section, you can visualise this as the size of a scoop collecting water from a stream, or something similar. Cadmium just happens to have a very large cross section for slow neutrons which are the main cause of the fission chain reaction in a reactor. Boron has similar properties. The precise reason for this involves study of nuclear physics, which you will have to read up in a scientific book on the subject, to get some understanding.
Why nuclear fission take high temperature for a raection?
Not at all, the temperature of U-235 or Pu-239 which are used for nuclear energy production by fission, has no effect on the fission reaction, which is driven only by the capture cross-section for neutron capture. Slow neutrons are captured more strongly than fast ones, so it is an advantage for the moderator not to be at a high temperature.
Is nuclear cross section is measured in barn?
Yes, crosssections are measured in barns.
Is energy released from uranium 238 when the atom splits?
1. Energy (heat) 2. Fast neutrons 3. Fission products (atoms of other elements of lower atomic weight, often very radioactive). All three are produced simultaneously, for every fission that occurs.
Fast neutron detection by helium 3 ionization chamber?
Helium-3 has a high cross section for thermal neutron absorption. For fast neutrons you must either thermalize the neutrons for use with boron or helium-3 based proportional counters or use a fast fission chamber based on fast fission of uranium. It's worth noting that a uranium based fast fission detector is really only useful in extraordinarily high neutron fluxes like that of a reactor.
Why does cadmium absorb neutrons during nuclear fission in a nuclear reactor?
Different elements absorb neutrons to different extents. The measure of this is called the neutron absorption cross section, you can visualise this as the size of a scoop collecting water from a stream, or something similar. Cadmium just happens to have a very large cross section for slow neutrons which are the main cause of the fission chain reaction in a reactor. Boron has similar properties. The precise reason for this involves study of nuclear physics, which you will have to read up in a scientific book on the subject, to get some understanding.
What is mearnt by fission cross-section?
In nuclear physics, a cross section is essentially the probability that a nucleus will interact with something. An isotope with a high fission cross section, like U-235, is very likely to absorb a thermal (slow) neutron and undergo fission. The cross section has units of area, usually cm2, which is where the name comes from. When the cross section is multiplied by the neutron flux, the product is the fission rate, or number of fissions per second.
What is the function of the control rods in a nuclear reactor?
They are used in nuclear reactor to control the rate of fission of uranium and plutonium. Because these elements have different capture cross sections for neutrons of varying energies, the compositions of the control rods must be designed for the neutron spectrum of the reactor it is supposed to control.
What is the function of the control rods in a nuclear reactors?
They are used in nuclear reactor to control the rate of fission of uranium and plutonium. Because these elements have different capture cross sections for neutrons of varying energies, the compositions of the control rods must be designed for the neutron spectrum of the reactor it is supposed to control.
Why nuclear fission take high temperature for a raection?
Not at all, the temperature of U-235 or Pu-239 which are used for nuclear energy production by fission, has no effect on the fission reaction, which is driven only by the capture cross-section for neutron capture. Slow neutrons are captured more strongly than fast ones, so it is an advantage for the moderator not to be at a high temperature.
Why the concept of nuclear cross section is so frequently used in nuclear physics?
A nuclear cross section is a "technical" way of saying how large a "target" a given atomic nucleus presents to an incoming neutron. And we need to know that about different elements, and about the different isotopes of those elements. There are some other applications, but this is the "biggie" for the use of the term nuclear cross section. And we need to start with the idea that fission begins with a neutron entering an atomic nucleus to cause fission. If your model of nuclear fission is a cue ball breaking a rack of billliard balls, we need to refine it. Get you from the "B" grade to an "A" grade in physics. A neutron doesn't "smash" an atomic nucleus. It is captured by it (neutron capture) and an instability results. A neutron released in the fission process comes away from the fission event like a bullet out of a gun. Because it is moving so "fast" it has a low probability of being captured. It needs to undergo some scattering (little "collisions" with other atomic nuclei) to slow it down (thermalize it). The thermal neutron has a higher probability of being captured by a given nucleus and causing another fission, if it is captured by a fissionable atom. We've seen how the energy of the neutron affects its probability of being captured, but it turns out that different elements present a different sized "target" for the neutron. The size depends on the energy of that neutron, but also on the element being targeted, and which isotope of that element is under consideration. To repeat, each element has a different nuclear cross section (target size) for a neutron (of a given energy), and each isotope of a given element has a different nuclear cross section (for that same given neutron energy). Three things are at work. The energy of the neutron aside, the element and the different isotopes of each element have different probabilities of capturing a neutron of a given energy. The nuclear cross section is a measure of the "receptivity" of a given nucleus to an incoming neutron. It's that probability of capture. That's it in a nutshell. Links can be found below.
Is nuclear cross section is measured in barn?
Yes, crosssections are measured in barns.
Is energy released from uranium 238 when the atom splits?
1. Energy (heat) 2. Fast neutrons 3. Fission products (atoms of other elements of lower atomic weight, often very radioactive). All three are produced simultaneously, for every fission that occurs.
What does the word fast refer to in the term liquid metal fast breeder reactor?
In a fast reactor there is no moderator, which in most (almost all) fission reactors used for power production is provided to slow down the neutrons produced in the fission reaction. This is because the capture cross-section of U-235 and PU-239 is much larger for slow neutrons, enabling the use of low enrichment fuel, or even natural uranium fuel with a graphite or heavy water moderator. In a fast reactor the fission chain reaction is sustained by fast neutrons, ie as produced by the nuclear fissions. This requires a higher enrichment of the fuel. Typically this could be 20 percent Pu-239, and the remainder Uranium. This type of reactor can actually breed more plutonium from the U-238 in the fuel and in a blanket around the reactor, since neutrons are absorbed into the U-238 turning it into Plutonium. However liquid metal (sodium or sodium/potassium) is nasty stuff to handle and the costs of the engineering involved have not been attractive enough for commercial use so far.
Fast neutron detection by helium 3 ionization chamber?
Helium-3 has a high cross section for thermal neutron absorption. For fast neutrons you must either thermalize the neutrons for use with boron or helium-3 based proportional counters or use a fast fission chamber based on fast fission of uranium. It's worth noting that a uranium based fast fission detector is really only useful in extraordinarily high neutron fluxes like that of a reactor.
What is the source of energy in nuclear reactor?
The source of energy in a nuclear reactor is the release of binding energy, i.e. the binding energy that hold protons and neutrons together in the nucleus of the atom. Heavy nuclides, such as uranium, are split into lighter nuclides, such as cesium and barium (and many others, in a semi-random cross section). The binding energy required to hold the original uranium together is less than the daughter products and is released to the system in the form of heat and other radiation.
Do you have a humorous speech?
why did the chicken cross the playground? Two get to the other slide!! why did the chicken cross the road? TO GET AWAY FROM THE EVIL LORD CHASING HIM DOWN THE STREET AFTER HE DESTROYED HIS NUSUN NUCLEAR REACTOR AND ATE THE BACON WITHOUT BLABLABLABLABLA
