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Uranium produces spontaneous fissions in small numbers, and each fission releases two or three free neutrons, so there is always a source of neutrons present in any assembly of uranium fuel. If enough fuel is assembled, in a geometrical array with a moderator, the conditions are there to start a chain reaction, and this will happen whenever the reactor approaches what is called criticality, which is when the number of free neutrons present starts to reach a high level. The approach to criticality is controlled by slowly withdrawing the control rods, and if at stages the rods are held steady, the neutron flux also steadies out. As criticality is approached, the flux gets higher and when the rods are pulled a bit more beyond the critical point it will start to increase exponentially, the reactor is then said to be supercritical and the neutron flux will go on increasing with a certain doubling time. So with a nuclear reactor there is no need to do anything to cause "ignition" as in a coal furnace, it is just a matter of getting the amount of neutron absorber reduced to the point where the reactor is critical. Note that often a neutron source is loaded into the reactor as a permanent feature, this is done to enable the flux measuring instruments to see a reading during the approach to critical, but even without this the reactor will still start itself, if the rods are withdrawn.
What else can I help you with?
Do chain reaction takes place in nuclear reactor?
Yes, chain reactions take place in nuclear reactors. In a nuclear reactor, the chain reaction involves the splitting of uranium atoms (fission) which releases energy and more neutrons, leading to further fission reactions. Control rods are used to regulate and maintain the chain reaction at a steady rate.
Who invented chain reaction?
The concept of a chain reaction was first described by Hungarian physicist Leó Szilárd in 1933. He later patented the idea of a nuclear reactor based on a self-sustaining chain reaction. The first controlled nuclear chain reaction was achieved by a team of scientists led by Enrico Fermi in 1942 as part of the Manhattan Project.
What is meant by chain reaction in nuclear reactor?
Basically a chain reaction (nuclear or chemical) is a self sustaining auto-catalytic reaction.In a nuclear reactor it is a neutron chain reaction, where each neutron released in every fission event can trigger another fission event. In a nuclear reactor the excess neutrons must be disposed of, which is the purpose of the control rods so that the reaction can be kept at some desired constant rate.
How are nuclear chain reaction to controlled in nuclear power plants?
Nuclear chain reactions in nuclear power plants are controlled by inserting control rods made of materials like boron or cadmium into the reactor core. These control rods absorb neutrons, reducing the number available to sustain the chain reaction. By adjusting the position of the control rods, operators can regulate the reactor's power output.
What is meant by TNT in nuclear reaction?
TNT (trinitrotoluene) is a conventional explosive used to trigger the beginning of a nuclear reaction in some nuclear weapons. When the TNT detonates, it generates the high temperatures and pressures needed to initiate the fission process in the nuclear material, causing a chain reaction to occur.
What starts the nuclear chain reaction in a nuclear reactor?
The nuclear chain reaction in a nuclear reactor is started by the splitting of uranium atoms, a process known as nuclear fission.
What particle is needed to begin nuclear chain reaction?
Neutron particle is needed to begin nuclear chain reaction.
What particles maintain a nuclear chain reaction?
In most cases neutrons are emitted and capable of maintaining a nuclear chain reaction
What controls the chain reaction in a nuclear reaction?
moderator
What particle is used to start nuclear fission?
In actuality, a spontaneous fission event begins a nuclear chain reaction. It kick starts a nuclear chain reaction. And a neutron from that fission will initiate another fission to continue and rev up that nuclear chain reaction.
What is it called when nuclear fission is repeated?
It is called nuclear chain fission reaction.
What emitted particles maintain a nuclear chain reaction?
In most cases neutrons are emitted and capable of maintaining a nuclear chain reaction
Is Nuclear bomb is a chain reaction?
Yes.
What causes the nuclear reaction to keep going once it has started?
The nuclear reaction in nuclear power plants continues because of a self-sustaining chain reaction. In this process, neutrons produced by fission cause further fission in other uranium or plutonium nuclei, releasing more energy and more neutrons. This chain reaction is controlled and moderated by control rods to maintain a stable and controlled release of energy.
What was the year of the first nuclear chain reaction?
1942
Is nuclear fission a chain reaction?
Not of itself, but it can be made to be.
What is the meaning of nuclear reactor?
It is a device where a controlled nuclear fission chain reaction occurs.
