Q. Which of the following is used as coolant in Atomic reactor?
Answer: Water
Notes: Almost all currently operating nuclear power plants are light water reactors using ordinary water under high pressure as coolant and neutron moderator. A coolant plays an important role in components of nuclear power plant and serves the dual purpose of removing the heat from the reactor as well as transferring it to the electricity generation circuit either directly or indirectly depending on the type of nuclear reactor being used for the purpose.