During nuclear fission process, the speed of neutrons is reduced to a critical value by using following moderators:

A. Deuterium

B. Graphite

C. Monazite

D. Tritium

E. Heavy Water

Choose the correct answer from the options given below:

Key Points

Nuclear power plants are a type of power plant that use the process of nuclear fission in order to generate electricity. 

• Nuclear energy originates from the splitting of uranium atoms – a process called fission.
• This generates heat to produce steam, which is used by a turbine generator to generate electricity.
• Because nuclear power plants do not burn fuel, they do not produce greenhouse gas emissions.
• Nuclear power provides the world with around 11% of its total electricity, with the largest producers being the United States and France.

Important Points

• Any nuclear reactor that produces power via the fission of uranium (U-235) or plutonium (Pu-239) by bombardment with neutrons must have at least five components:
• nuclear fuel consisting of fissionable material, a nuclear moderator, reactor coolant, control rods, and a shield/containment system.

Moderator in Nuclear Power plant:

• The moderator is a material intentionally placed in a nuclear reactor core to slow neutrons down from their initial fast speeds.
• Adding a moderator makes it much easier to attain a nuclear chain reaction. In common water-cooled nuclear reactors, the moderator is the same thing as the coolant: water.
• 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
• Heavy water is a form of water that contains only deuterium rather than the common hydrogen-1 isotope that makes up most of the hydrogen in normal water. 

Therefore we conclude that the correct answer is B and E only.