Inside the reactor vessel, the fuel rods are immersed in water which acts as both a coolant and moderator. The moderator helps slow down the neutrons produced by fission to sustain the chain reaction. Control rods can then be inserted into the reactor core to reduce the reaction rate or withdrawn to increase it.
What is the function of moderator?
Moderators are the substance that slows down the neutrons in nuclear reactors. Moderators are made up of materials with light nuclei that do not absorb the neutrons but slow down the speed of neutrons by a series of successive collisions.
What is moderation in nuclear reactor?
A material, such as ordinary water, heavy water, or graphite, that is used in a reactor to slow down high-velocity neutrons, thus increasing the likelihood of fission.
What is the function of moderators in nuclear reactor 1 point?
In nuclear reactors, moderator is used to slow down the fast moving neutrons.
Which is used moderator in nuclear reactor?
Water (sometimes called “light water” in this context) is the most commonly used moderator (roughly 75% of the world’s reactors). Solid graphite (20% of reactors) and heavy water (5% of reactors) are the main alternatives.
Why graphite is used as a moderator in nuclear reactor?
The graphite bricks act as a moderator. They reduce the speed of neutrons and allow a nuclear reaction to be sustained.
How do moderators work in nuclear reactor?
Slow neutrons strike nuclei of uranium-235, causing the nuclei to fission, or split, and release fast neutrons. The fast neutrons are absorbed or slowed by the nuclei of a graphite moderator, which allows just enough slow neutrons to continue the fission chain reaction at a constant rate.
What is Electronic moderator?
Moderator consists of graphite rods/Beryllium/Heavy water which enclose the fuel rods. Moderator slows down the neutrons in nuclear reactor. Moderators are made up of materials with light nuclei that do not absorb neutrons but slow down the speed of neutrons by a series of successive collisions.
Why is water a good moderator?
Moderator is required in a Nuclear reactor to slow down the neutrons produced during the fission reaction so that the chain reaction can be sustained. Heavy Water is an excellent moderator due to its high moderating ratio and low absorption cross section for neutrons.
What is the function of moderator and reflector in nuclear power plant?
function in nuclear reactor
A reflector is a region of unfueled material surrounding the core. Its function is to scatter neutrons that leak from the core, thereby returning some of them back into the core.
What is the coolant used in nuclear reactor?
A substance circulated through a nuclear reactor to remove or transfer heat. The most commonly used coolant in the United States is water. Other coolants include heavy water, air, carbon dioxide, helium, liquid sodium, and a sodium-potassium alloy.
Which is used as a moderator in nuclear reactor Mcq?
Heavy water is used as a moderator in nuclear reactors.