Video Transcript
Which of the following is one of
the uses of water being passed through the reactors in many nuclear power
stations? (A) The water takes part in the
chain reaction, reacting with uranium. (B) The water acts as a coolant,
stabilizing the temperature of the core. (C) The oxygen atoms in the water
molecules provide free electrons for fission. (D) The hydrogen atoms in the water
absorb neutrons. (E) The water washes away
radioactive waste as it is produced.
To answer this question, let’s take
a closer look at a nuclear power station. Nuclear power stations generate
electricity through the controlled nuclear fission chain reaction involving neutrons
and uranium-235.
The fission chain reaction needs to
be carefully controlled. Control rods are added to the
reactor core to absorb excess neutrons, which reduces the rate of the chain
reaction. Water in the reactor core acts as a
neutron moderator, slowing the neutrons, which helps to maintain the chain
reaction. By carefully monitoring the control
rods and moderators, the fission reaction can be safely sustained.
The reaction produces a lot of
heat, so the water in the core also acts as a coolant. Hot water and steam is released
through the top of the reactor core. The hot water and steam pass
through a boiler, where it is cooled down and pumped back into the reactor core. During this process, the water in
the boiler is turned into steam. The pressure from the steam spins a
turbine that generates electricity. The steam is then condensed back
into liquid water using more water from large cooling towers.
We can see from the diagram that
water plays a key role in several components of a nuclear power station. The question specifically asks
about the uses of water being passed through the reactor. In the reactor core, water is used
as a moderator to slow the neutrons and as a coolant. Therefore, the answer choice that
is one of the uses of water being passed through the reactors in many nuclear power
stations is answer choice (B). The water acts as a coolant,
stabilizing the temperature of the core.
