Question

The function of heavy water in a nuclear reactor to
A.Slow down the neutrons
B.Increase the neutrons
C.Stop the electrons
D.None of these

Answer 1

Hint: This question is purely based on our knowledge of nuclear reactors. If we know about the nuclear reactors, we could easily answer this question. Also, we need to be aware of the components that are used in a nuclear reactor.

Complete step by step answer:
We need to know the components of a nuclear reactor. So, below we have the components of a nuclear reactor:
-Fuel – which is generally Uranium
-Moderator – it is used to slow down the neutrons released from fission to create more fission. Generally, water, heavy water or graphite is used for this purpose.
-Control rods or blades – They are basically made with neutron absorbing material such as cadmium, hafnium, boron and are inserted from the core to control the rate of reaction.
-Coolant- It is a fluid circulating through the core so as to transfer the heat from it.
-Pressure vessel or pressure tubes – It is usually a robust steel vessel containing the reactor core and moderator or coolant but it may be a series of tubes holding the fuel and conveying the coolant through the surrounding moderator.
-Steam generator – It is the part of the cooling system of pressurized water reactors where the high pressure primary coolant brings heat from the reactor.

Step two
As, we can conclude from step one that heavy water is used as a moderator to slow down the speed of the neutrons.
Hence, option (A), i.e. slow down the neutrons, is the correct choice of the given question.

Note:
In heavy water nuclear reactors, when neutrons bombard U-238, some uranium atoms absorb an additional neutron and are transformed into Pu-239. Heavy water provides a path to turn common uranium into plutonium, used as common fuels in nuclear bombs.