a moderator would slow the neutrons, hindering breeding
No, a breeder nuclear reactor does not typically use a moderator. Breeder reactors are designed to produce more fissile material than they consume by using fast neutrons to convert non-fissile isotopes into fissile ones without slowing down the neutrons.
The most common moderator used in nuclear reactors is water, particularly light water (H2O). Water slows down the fast neutrons produced during fission reactions, allowing them to more easily induce further fission events.
Neutrons released from the fissioning, or splitting, of Uranium or Plutonium atoms collide with the molecules of the moderator, losing some of their energy in the process. This slows the neutrons down (slow neutrons are referred to as "thermal" neutrons") so that they are more likely to cause fission when colliding with another Uranium or Plutonium atom. In the most common types of reactors the moderator used is ordinary distilled water which is also used as the coolant for the reactor. Graphite and heavy water can also be used, and there are types of reactors which use no moderator at all - they operate on "fast" neutrons alone.
No, control rods in nuclear reactors are not made of graphite. The control rods have to be able to gather up the neutrons to shut the reactor down, so boron is often selected. Graphite is used in some reactors as a moderator, and a moderator slows down neutrons. The slower neutrons have a greater ability to undergo neutron capture to continue the chain.
Graphite can be used as a moderator, that is to slow down the fast neutrons produced in fission. Early reactors including Hanford and Windscale used graphite, and in the UK this type of reactor was built extensively for power production. However water reactors such as PWR and BWR have proved cheaper to build and have a longer life, so graphite is now little used, there are a few still running but none being planned or built as far as I know.
a moderator would slow the neutrons, hindering breeding
Yes, they are fast nuclear reactors
No, a breeder nuclear reactor does not typically use a moderator. Breeder reactors are designed to produce more fissile material than they consume by using fast neutrons to convert non-fissile isotopes into fissile ones without slowing down the neutrons.
In a majority of reactors, water is used as an efficient moderator. It helps slow down the fast neutrons produced during nuclear reactions, making them more likely to cause further fission reactions in the reactor core.
efficient coolant that does not act as a neutron moderator.
Yes, it is the main moderator function in what is called "thermal nuclear reactors"
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.
Yes, tritium water can be used as a moderator in a nuclear reactor. However, tritium itself is a radioactive isotope of hydrogen, so careful handling and safety measures are required due to its potential health risks. Research is being conducted on the use of tritium in nuclear fusion reactors, but it is not commonly used as a moderator in fission reactors.
Most nuclear reactors are thermal-neutron reactors. A few fast breeder reactors have been built, but not many.
A moderator is a material that slows fast neutrons.
Carbon is a very good moderator, for use in gascooled reactors, the others not.
Liquid sodium has been used as a coolant in fast reactors, because it does not slow down and absorb fast neutrons. It does not control the nuclear reaction directly, for that variable neutron absorbers are required.