Nuclear power plants have risen in numbers over the years. There are over 400 nuclear power plants across the world as of 2019. Currently, more than 14% of the world’s electricity comes from nuclear power plants.
In 2018, nuclear power plants in the US alone generated 807.1 billion kilowatts of energy, accounting for 20% of the nation’s electricity.
How do nuclear power plants create energy?
The simple answer is by nuclear reaction. However, if you dig a little deeper, you will uncover a set of complex processes that enable us to harvest energy from nuclear particles.
And in this guide, we will be thorough!
Nuclear reactions are of two types – Nuclear Fission and Nuclear Fusion. We use Nuclear Fission to generate power from nuclear reactors. The reason why we don’t use nuclear fusion is that we don’t have the technology that’s mature enough to carry out the process safely and cost-effectively.
Although, research is already underway to create a sustainable fusion of energy.
The energy released from the nuclear reactions is in the form of heat.
In nuclear power plants, this heat emitted from the reactions is used to turn water into superheated steam. This steam is then used to turn a turbine which is connected to a generator.
As the turbine spins, the generator begins to produce energy.
What is nuclear fission and how does it work?
Nuclear fission is the process of splitting an atom. When an atom is split, it releases a massive amount of energy.
Nuclear power plants that we use today harness this power and convert it into electrical energy.
An atom has a nucleus and electrons orbiting around it. The nucleus of an atom consists of neutrons and protons. The nucleus is held together by a force called Strong Nuclear Force.
This is the strongest force found in nature.
One way we can overcome this force and split an atom is by hitting the nucleus with a neutron.
In nuclear fission, we use uranium atoms because of their large atomic size. The large size means that the atomic force within it is not that strong.
Hence, there is a greater chance of splitting the nucleus.
Another advantage of uranium is that even though it is rare in nature, the radioactivity of uranium supplies a constant flow of energy. One pound of uranium produces equivalent energy as that of three million pounds of coal.
In nuclear fission, high energy neutrons are made to bombard the uranium nuclei. The bombardment causes the nucleus of the uranium nuclei to split.
This process releases a large amount of energy and the neutrons within the uranium nuclei also get released. These neutrons then go on to bombard with other uranium atoms.
This process turns into a chain reaction where each bombardment leads to more bombardments. To ensure that this chain reaction doesn’t go out of hand, nuclear reactors use control rods that absorb neutrons.
Nuclear fission creates temperature up to 520°F (270°C) at the center of the nuclear reactor.
Types of nuclear power plants
All nuclear plants are not the same. They are similar in the type of nuclear fuel that they use but differ in the way water is heated and turned to steam.
Based on this classification, nuclear power plants can be broadly divided into two:
- Boiling water reactor (BWR)
- Pressurized water reaction (PWR)
Pressurized water reactor (PWR): A Pressurized water reactor is the most common type of nuclear power plant. In the Pressurized water reactor or PWR, there are two containers for water.
The first container is within the reactor and is pressurized using a pressurizer. Pressurizing water raises the boiling point of the water.
In PWR, the pressure is set to 150 Mpa which causes the boiling point to be around 644°F (340°C). Water enters the reactor at 554°F (290°C) and leaves it at 608°F (320°C).
The hot water leaving the reactor is passed through tubes that are placed in the second container. Water in the second container is not pressurized at all, so it starts to boil as soon as the hot water passes through the tubes, generating steam to turn the turbine.
Boiling water reactor (BWR):A boiling water reactor does not use the two-chamber approach of the PWR. Instead, the water that flows through the reactor is the same water that turns the turbine.
Once water enters the reactor, it turns into steam as the temperatures within the reactor are at 545°F (285°C). The actual efficiency of a boiling water reactor (BWR) is around 33-34%.
Advantages of nuclear power plants
There are numerous advantages to moving away from fossil fuel-based power plants to nuclear-powered ones. We have listed down a few below:
- Advancements in scanning and mining have enabled relatively low-cost uranium supply
- Uranium has a very high energy density, many times more than fossil fuels in weight
- Nuclear power plants are capable of producing a constant supply of energy
- Zero greenhouse gas emission
- High power generation for a relatively small area when compared with solar or wind alternatives.
When we look at the disadvantages of nuclear power plants, there are only two that come up. Firstly, the initial cost of a nuclear power plant is very steep and is in billions. Secondly, the radioactive waste that is a byproduct of nuclear reaction.
Nuclear energy is one of the most reliable forms of energy that is in use today. Over the years, we have seen a gradual rise in the number of nuclear plants in the world.
With new advancements in nuclear energy research like substituting thorium instead of uranium, we can ensure a steady supply of nuclear fuel for the coming ages. We are also in active research on ways to dispose of the nuclear waste created by nuclear power plants.
In essence, we can say without a doubt that nuclear energy is here to stay!