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What is the function of moderator and control rods in fission reactors?
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How is the rate of the fission in a nuclear reactor controlled?
By the control rods and by the moderator.
What are the functions of the moderator and the control rods in a fission reactor?
Moderator: slows fast fission neutrons (several MeV energy) to slow "thermal" neutrons ( <5eV energy), making it less likely for Uranium-238 to capture them and more likely for them to cause fission of Uranium-235. Breeder reactors don't use moderator. Control rods: absorb excess neutrons to allow the operating reactor to be kept EXACTLY critical and under control. They are equivalent to the accelerator & brake in a car. SCRAM rods: absorb neutrons for emergency shutdown. They are equivalent to emergency brake in a car. Did I answer more than you asked?
What is fission temperature?
Fission of U-235 or Pu-239 is not very sensitive to temperature, but neutrons are absorbed better if they are slowed down after production, this is the function of the moderator.
What are the three main advantages of a fusion reactor compared to a fission reactor?
Nuclear fusion reactors do not exist yet as we don't know how to build them. All nuclear reactors are nuclear fission reactors.
Is nuclear energy effective?
Yes, nuclear fission reactors are very effective and can generate a lot of power. That is why nuclear fission reactors are very effecive
Do moderator in nuclear reactor slows down the neutrons emitted during fission?
Yes, it is the main moderator function in what is called "thermal nuclear reactors"
What are the functions of the deuterium and tritium atoms in nuclear reactors?
All current nuclear reactors are fission reactors, tritium has no function in a fission reactor, in standard water moderated reactors deuterium also has no function, in heavy water moderated reactors deuterium is the moderator. If we are ever able to make a fusion reactor, deuterium/tritium mix will be used as fuel.
How is the rate of the fission in a nuclear reactor controlled?
By the control rods and by the moderator.
What are the functions of the moderator and the control rods in a fission reactor?
Moderator: slows fast fission neutrons (several MeV energy) to slow "thermal" neutrons ( <5eV energy), making it less likely for Uranium-238 to capture them and more likely for them to cause fission of Uranium-235. Breeder reactors don't use moderator. Control rods: absorb excess neutrons to allow the operating reactor to be kept EXACTLY critical and under control. They are equivalent to the accelerator & brake in a car. SCRAM rods: absorb neutrons for emergency shutdown. They are equivalent to emergency brake in a car. Did I answer more than you asked?
A nuclear reactor produces energy from uncontrolled fission?
False, the fission in nuclear reactors is controlled with the movable control rods.
What nuclear reaction does the us use?
All thermal reactors, that is those using a moderator to slow down the fission neutrons, use the same reaction. In the US all commercial reactors (104 of them) are either PWR or BWR types.
What is fission temperature?
Fission of U-235 or Pu-239 is not very sensitive to temperature, but neutrons are absorbed better if they are slowed down after production, this is the function of the moderator.
Which are needed in fission reactor?
nuclear fuelcoolantneutron moderator (if needed)control elementsshieldingmeasurement instrumentationemergency systemssupport structures
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 are the basic feartures of a fission reactor?
The fission reactor is composed of:Nuclear fuel,reactor coolants,neutron moderator (optional)control elementsshieldingmeasurement instrumentssupporting structures... etc
What are the uses of carbon heavy water and concrete in the nuclear reactor?
Carbon in the form of graphite is used in some types of reactors as the moderator*.Heavy water is used in some types of reactors as the moderator*.Light water is used in some types of reactors as the moderator*.Light water is used in most current types of reactors as coolant and in the form of steam to drive the turbines.Liquid metals (Sodium, NaK, Mercury, etc.) are used in some types of reactors as coolant.Concrete, often borated concrete to absorb neutrons better, is used in reactors as radiation shielding.*Moderator: a material that slows highly energetic fission neutrons rapidly to thermal energies to prevent their capture by Uranium-238 and increase their chance of causing more fissions of Uranium-235 to keep the reactor running.
Do fusion powers nuclear reactors?
No. Our reactors are fission reactors. We haven't yet mastered fusion reactors for power.
