Question

The purpose of using heavy water in a nuclear reactor is:
A.) To cool the reactor to room temperature
B.) To make the dynamo blades to work well
C.) To decrease the energy of fast neutrons
D.) In increasing the energy released in nuclear fission

Answer 1

Hint: In a chain reaction, nuclear power plants harness the energy of countless atoms of uranium. Heavy water helps to keep such a chain reaction for a long time running. When each uranium atom breaks apart, it shoots out neutrons that can go on to split other atoms.

Complete step by step solution:
Because of the composition of water, so many reactions are happening.

Water has a composition of hydrogen and oxygen because the formula of light water is ${{H}_{2}}O$. In heavy water, it contains hydrogen which is also known as deuterium. It is written as ${}^{2}{{H}_{2}}O\text{ or }{{\text{D}}_{2}}O$. As you can see the molecular formula of deuterium looks different than the usual molecular formula of water. So deuterium is different from hydrogen usually found in water. Hydrogen from water is known as protium. Deuterium contains a proton and a neutron both but in protium contain proton only.

The purpose of using heavy water in a nuclear reactor is to cool the reactor to room temperature. To ensure an effective fission chain reaction occurs, the neutrons must be slowed down. The process of slowing down neutrons is called moderation. The material used to slow down these neutrons is a neutron moderator. Deuterium in heavy waterworks works as a moderator because it absorbs fewer neutrons from hydrogen and this is very important. Nuclear reactor requires neutrons to carry out chain reactions.

Answer- (A)

Note: Heavy water forms naturally but its quantity is much lower compared to regular water. Approximately, one water molecule if heavy water is equal to twenty million water. Deuterium is a stable isotope therefore heavy water is not radioactive.