Which material is used as a neutron moderator?

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.

Is graphite a neutron moderator?

Graphite has been a popular moderator in the past, however, one drawback is that it needs to be extremely pure to be effective. Graphite can be made artificially using boron electrodes, however, since boron is a very good neutron absorber— a small amount of contamination will make the graphite an ineffective moderator.

What is the best neutron moderator?

Graphite is also a very effective moderator. Carbon is a very stable nucleus reluctant to accept a new neutron. The first nuclear reactor designed by Enrico Fermi in 1942, which functioned during the Second World War with natural uranium was “moderated” using graphite.

Why is graphite used as a moderator in nuclear reactors?

The graphite bricks act as a moderator. They reduce the speed of neutrons and allow a nuclear reaction to be sustained.

Which material is used as a moderator?

Typical materials used for this purpose are hydrogen, deuterium (heavy hydrogen), and carbon. The moderator and coolant may be the same (e.g., water) or may be separate materials (e.g., gaseous coolant and solid graphite moderator).

Which of the following material can be used as a moderator?

Explanation: At present the common moderator materials used are graphite, ordinary water and heavy water. Oxygen is not suitable to use due to its low density and the consequent small number of collision. 4. Which of the following part of nuclear reactor is used to control the rate of reaction.

Is graphite a neutron reflector?

A neutron reflector is any material that reflects neutrons. This refers to elastic scattering rather than to a specular reflection. The material may be graphite, beryllium, steel, tungsten carbide, gold, or other materials.

Why is d2o used as moderator?

Heavy water is used as a moderator in some reactors because it slows down neutrons effectively and also has a low probability of absorption of neutrons. …

Does graphite absorb neutrons?

The graphite should absorb as few neutrons as possible during the moderating process because neutrons absorbed in any reactor component other than the fuel (parasitic absorption) are lost from the chain reaction. For natural-uranium reactors a low neutron-absorption rate in the moderator is especially important.

Which substance is used as moderator in nuclear reactor?

The neutron leaves the surface very fast, so moderator substances are used to slow down the neutron for a controlled chain reaction. Therefore, the substance used as a moderator in the reactor of a nuclear power plant is graphite and the option (C) is correct.

Which of the following materials Cannot be used as a moderator?

Most commonly used moderators are graphite and heavy water (D2O) . Water cannot be used as moderator in a nuclear reactor.