Which of the following statements are true regarding the nuclear reactor?
Which of the following statements are true regarding the nuclear reactor?
The correct options are
A A nuclear reactor uses control rods, generally made of Cadmium to switch on or switch off the energy generation process.
B A nuclear reactor uses moderators to slow down the neutrons to continuously generate the energy.
Let's do it one by one.
Control rods are the neutron absorbers. Elements like Cadmium and Graphite have a property of absorbing fast neutrons.
Neutrons are the one who keeps the chain reaction going in a reactor, so if the neutrons are absorbed, there will be no further reaction. So we can say that control rods are used as a switch in a nuclear reactor.
Moderators, as their name suggest are used to "moderate" the energy of a neutron. Why do we need to do that?
Simple. The neutrons emitted as the product of fission of U-236 are fast neutrons. Their energy range is of tens of MeVs. While a U-235 can only absorb a slow neutron, whose energy range is few eVs. So we need to reduce the energy of a neutron and moderators do it.
A fast neutron makes several collisions with the bulk of a moderator (like heavy water, Beryllium etc.) and slows down and hence is reduced to get absorbed by a U-235.
Moderators are not the coolants. No doubt a huge amount of heat is generated in the process as we have already discussed but in a nuclear power plant that heat is used to vaporize water and hence to create steam which on high pressure is used to rotate the turbine to produce electricity.
A A nuclear reactor uses control rods, generally made of Cadmium to switch on or switch off the energy generation process.
B A nuclear reactor uses moderators to slow down the neutrons to continuously generate the energy.
Let's do it one by one.
Control rods are the neutron absorbers. Elements like Cadmium and Graphite have a property of absorbing fast neutrons.
Neutrons are the one who keeps the chain reaction going in a reactor, so if the neutrons are absorbed, there will be no further reaction. So we can say that control rods are used as a switch in a nuclear reactor.
Moderators, as their name suggest are used to "moderate" the energy of a neutron. Why do we need to do that?
Simple. The neutrons emitted as the product of fission of U-236 are fast neutrons. Their energy range is of tens of MeVs. While a U-235 can only absorb a slow neutron, whose energy range is few eVs. So we need to reduce the energy of a neutron and moderators do it.
A fast neutron makes several collisions with the bulk of a moderator (like heavy water, Beryllium etc.) and slows down and hence is reduced to get absorbed by a U-235.
Moderators are not the coolants. No doubt a huge amount of heat is generated in the process as we have already discussed but in a nuclear power plant that heat is used to vaporize water and hence to create steam which on high pressure is used to rotate the turbine to produce electricity.
