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Do moderator in nuclear reactor slows down the neutrons emitted during fission?
Wiki User
∙ 9y ago
Yes, it is the main moderator function in what is called "thermal nuclear reactors"
Wiki User
∙ 9y ago
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In a nuclear reactor why does the moderator need to slow down the neutrons?
Nuclear fission of Uranium-235 is more efficient when hit by neutrons with low energy of the order of electron volts. However, neutrons coming from fission are at high energies around 2 megaelectron volt. Accordingly, the moderator is needed to slow down the neutrons coming from fission to low energy values through scattering process with moderator molecules. This is the concept of the so called "thermal nuclear reactors"
Why is the moderator important in a nuclear reactor?
The moderator is used to slow down the neutrons present in the core of the reactor. Normally the neutrons produced as the nuclear fuel (e.g. uranium) is fissioned are travelling too fast to produce a sustained chain reaction. Some examples of moderators are cadmium, heavy water and graphite.
Why moderator is not used in case of fast breeder reactor?
Moderator is not used in case of fast breeder reactor because there is no need to slow down neutron energy. Nuclear fission takes place at high energy of neutrons.
In nuclear reactor heavy water is used as?
Heavy water (deuterium) functions as a moderator. It slows down fast neutrons released by fission reactions in order to allow the reaction to be sustained. Fast neutrons pass through the reactor before initiating another fission reaction.
A neutron is an unstable particle outside a nucleus but to start nuclear fission requires the slowing down of a neutron. How is nuclear fusion carried out in the case of uranium?
The neutrons released from Uranium are fast neutrons. In a reactor they are slowed down by a moderator. The moderator could be water, heavy water, graphite, among others. When the neutron is slowed down, it is more likely to create fission.This is what happens with the U-235. The U-238 does not fission, but it does transmute through a series of neutron absorption and beta decay etc. into plutonium which does fission also.
In a nuclear reactor why does the moderator need to slow down the neutrons?
Nuclear fission of Uranium-235 is more efficient when hit by neutrons with low energy of the order of electron volts. However, neutrons coming from fission are at high energies around 2 megaelectron volt. Accordingly, the moderator is needed to slow down the neutrons coming from fission to low energy values through scattering process with moderator molecules. This is the concept of the so called "thermal nuclear reactors"
What does a moderator do in nuclear power plants?
The moderator slows (moderates their speed/energy) neutrons from the 1 MeV that they have when emitted in fission to less than 1 eV.The reason a moderator is needed in most reactors is that their fuel is still mostly Uranium-238, which easily captures 1 MeV neutrons and potentially stopping the neutron chain reaction but is unable to capture neutrons less than 1 eV which still easily fission the small percentage of Uranium-235 in the fuel.
Why is the moderator important in a nuclear reactor?
The moderator is used to slow down the neutrons present in the core of the reactor. Normally the neutrons produced as the nuclear fuel (e.g. uranium) is fissioned are travelling too fast to produce a sustained chain reaction. Some examples of moderators are cadmium, heavy water and graphite.
How does the role of the moderater work in nuclear power plants?
The moderator in a nuclear reactor slows (moderates) the neutrons that are released during fission, so that they can subsequently cause fission in other atoms. When the neutrons are initially released, they tend to have too much energy, which impacts their ability to cause subsequent fission.
Why you use moderators in a nuclear reaction chamber during a fission chain reaction?
A moderator in a fission chain reaction is a system (usually water) that slows neutrons down (decreases their energy) to the point where they can interact with fissile material, causing the fission reaction to be self sustaining. This is necessary because, without the moderator, the neutrons emitted from fission have too much energy to cause subsequent fission. The design of the moderator is such that it provides automatic control of the reaction. As it heats up, the moderation effect decreases, causing the reaction to decrease. Conversely, as it cools down, the moderation effect increases, causing the reaction to increase. In the event that the moderator fails, such as when a depressurization event causes the water to flash to steam, the loss of moderation causes the fission reaction to stop.
What is the moderator in nuclear power plants?
The moderator in a nuclear power plant is the substance that is used to slow down neutrons that are generated by the fission reactions. When fissile material fissions, fission fragments appear, as do neutrons. These neutrons, which leave the fission reaction with a heap of kinetic energy, might go on to cause more fissions (in a chain reactions) if they can be thermalized (slowed). Slowing (moderating) the neutrons increases the probability that they will be absorbed to cause another fission.Depending on the plant design, a few common ones now are:waterheavy watergraphitenone (in fast breeder reactors)
What is a moderator when it concerns nuclear energy?
A moderator is a material that slows fast neutrons.
The process in which each split atom gives up neutrons?
The act of an atom splitting is called nuclear fission. In nuclear fission where we see neutrons emerge with fission fragments, and we then see those neutrons initiate other fission reactions is called a nuclear fission chain reaction.
Slows down neutrons in a nuclear reactor?
moderator
Why moderator is not used in case of fast breeder reactor?
Moderator is not used in case of fast breeder reactor because there is no need to slow down neutron energy. Nuclear fission takes place at high energy of neutrons.
How is the rate of the fission in a nuclear reactor controlled?
By the control rods and by the moderator.
What is possibly happen to neutrons produce in a fission reactor?
The neutrons produced by fission in a nuclear fission reactor during the process of thermalization to be available for a new generation of fission could be subject to:absorption in fuelabsorption in non fuel reactor components (moderator, clad, structural material, ...)fast leakageresonance capture in U-238fast fission in U-238thermal leakage
