Nuclear Energy: An Overview
The energy demand has been increasing day by day due to the increase in population and rapid industrialization. We have been predominantly dependent on fossil fuels like coal and crude oil as a source of energy to power the industries and residential areas since the industrial revolution. This has created a huge negative impact on the environment. Over the last three decades, there have been major investments in renewable sources of energy like solar energy, wind energy, tidal energy and hydropower to encourage a transition towards an eco-friendly source of energy. In this blog, I would be explaining nuclear energy in detail.
What Is A Nuclear Power Plant?
Nuclear power plants are a type of power plant that works on the principle of nuclear fission to produce electricity. This is achieved by using nuclear reactors in combination with the Rankine cycle. The heat generated from the reactor is used to convert water into steam which in turn spins a turbine and generator. It is estimated that 11% of the world’s total electricity is from nuclear power.
Keeping aside the source of heat in the nuclear power plant, it's quite clear that they are quite similar to that of the coal-fired power plants. The safety protocols that need to be followed in a nuclear power plant are quite different from those used in a coal-fired power plant because of the high potential risk involved in getting thermal power from splitting the nuclei of atoms in their reactor core. The most commonly used fuel in nuclear powerplant is Uranium and Thorium has the potential to be used as fuel in nuclear power plants in the future.
History Of Nuclear Power Plant
The history of Nuclear Power dates back to the 1930s when Italian Physicist Enrico Fermi proved that neutrons could split atoms. In the year 1942, Enrico Fermi and his team of researchers achieved the first-ever nuclear chain reaction under a stadium at the University of Chicago. Enrico Fermi was the creator of the world’s first nuclear reactor, the Chicago Pile-1. He is also known as the “architect of the nuclear age” and the “architect of the atomic bomb”. He was also one of the very few physicists to have been exceptionally great in both practical and theoretical physics. He was awarded the Nobel Prize in Physics in the year 1938 for his demonstrations of the existence of new radioactive elements produced by neutron irradiation, and for his related discovery of nuclear reactions brought about by slow neutrons.
The 1950s saw many milestones in the nuclear energy sector. One such key milestone was the first electricity to be produced from the nuclear source at Idaho’s Experimental Breeder Reactor-I in the year 1951. On 20th December 1951, engineers and scientists at Idaho’s Experimental Breeder Reactor-I watched a string of four light bulbs spring to life with energy from a nuclear source. For the very first time in mankind’s history, electricity had been made with nuclear energy at the world’s first nuclear power plant.
In the year 1954, the Soviet Union (Presently The Russian Federation) established a nuclear power plant in the city of Obninsk which provide 5 milliWatt of electricity to the power grid.
On 17th October 1956, the world’s first-ever nuclear power plant was opened at Calder Hall at Windscale, England was connected to the national power grid. It was built for industrial-scale civilian power generation and connected to a national electrical grid.
Nuclear energy has come quite a long way from lighting a series of four bulbs in 1951 to generating power up to 2616.61 TWh of nuclear power generated globally in 2020.
In the year 2020, Around 10% of the global electricity demand comes from nuclear power. While some countries like France and Sweden rely heavily on nuclear energy as their main source of energy with more than 70% and 80% of electricity generation respectively.
Components Of A Nuclear Power Plant
There are various components that work together to produce power in a nuclear power plant. They are Nuclear Reactor, Steam Generation, Generator & Turbine and Cooling Towers. Now I would be explaining various components of the nuclear components in detail.
Nuclear Reactor
A nuclear reactor is a very important part of a nuclear power plant. It is like a heat source that contains the fuel & the nuclear chain reaction takes place inside the reactor. The nuclear fuel used in the nuclear reactor is Uranium and the nuclear fission reaction takes place inside the reactor. The heat generated in the reactor can be transferred to the coolant of the reactor to generate heat for all the parts in the power plant.
Steam Generation
The production of steam is a very common process in any nuclear power plant. Every nuclear power plant has a unique process and equipment to produce steam. The most common power plants use pressurized water reactors which uses two loops of circling water to produce steam. The first loop is used to carries extremely hot liquid water to a heat exchanger, where water is at a lower pressure is being circulated. It then heats up and boils to steam which is then sent to the turbine section to produce electricity.
Generator & Turbine
Once the steam is produced in the steam generator, it travels at a very high speed and speeds through at least one turbine. These get up to extremely high speeds, causing the steam to lose energy and therefore condensing back to cooler liquid water. The rotation in the turbine activates the generator to produce electricity for the power grids.
Cooling Towers
A cooling tower is arguably the most iconic symbol of nuclear power plants. The main function of a cooling tower is to reject waste heat to the atmosphere by the transfer of heat from hot water (from the turbine section) to the cooler outside air. The hot water cools in contact with the air and a small portion approximately 2% evaporates and rises up through the top. Importantly, these nuclear plants do not release any carbon dioxide which is the primary greenhouse gas that contributes to climate change.
Classification Of Nuclear Power Plants
Nuclear power plants are classified into seven main types based on their coolant used, the temperature of operation and nuclear fuel. They are as follows:
- Pressurized Water Reactor (PWR)
- .Boiling Water Reactor (BWR)
- Heavy Water Reactor (HWR)
- Gas Cooled Reactors (GCR)
- Thorium high-temperature reactor (THTR)
- RBMK
- Fast breeder reactors
Working Principle Of Nuclear Power Plant
Before understanding the working of a nuclear power plant, one must understand the two different types of nuclear reactions. They are nuclear fusion and nuclear fission.
The word Fission means splitting or breaking up into parts. Nuclear fission takes place when a large and unstoppable isotope is bombarded with by high-speed particles, usually neutrons. For example, when the Uranium-235 isotope is bombarded by a high-speed neutron unstable Uranium-236 isotope is produce which in turn splits into Krypton and Barium.
On the other hand, the word Fusion means the merging of separate elements into one unified entity. Nuclear fusion is a process where atomic nuclei combine together to form heavier nuclei resulting in the release of enormous amounts of energy. Fusion takes place when two low-mass isotopes(i.e Hydrogen Isotopes) unite under conditions of extreme pressure and temperature.
In the nuclear power plant, the fission takes place in the reactor. The middle of the reactor is called the core. The core contains uranium fuel which can be formed into pellets of ceramic. Every pellet has the potential to generate 150 gallons of oil energy. The total energy generated from the pellets is stacked in metal fuel rods. A bunch of these rods arranged together in a particular order is known as fuel assembly. The reactor core has several assemblies.
The heat is generated within the core of the reactor during the nuclear fission reaction. The heat generated can be used to convert water into steam which in turn activates the blades of the turbine. When these turbine blades begin to rotate, they start driving the generators that produce electricity. A cooling tower is used to cool the steam into water and this water is reused.
Radioactive Waste Produced In The Nuclear Power Plant And Its Disposal Methods
In this part of the blog, I have highlighted the various Radioactive Waste Produced In The Nuclear Power Plant. Disposal methods have been briefly explained here. The two main types of radioactive waste produced are as follows:
- Low-level radioactive waste: Low-level radioactive waste includes items that have become contaminated with radioactive material during energy production at the nuclear power plant. They include items such as shoe covers and clothing, wiping rags, mops, filters, reactor water, and tools. These wastes are generally stored in the nuclear plant for a temporary time period & after that, they are sent to the waste disposal site. If the low-level radioactive wastes are no longer radioactive in nature, then it is directly disposed of as ordinary waste.
- High-level radioactive waste: High-level radioactive waste includes the spent reactor fuel and wastes remaining after the spent fuel is reprocessed. The spent fuel is extremely radioactive in nature and must be stored in specially designed pools or containers. The high-level radioactive wastes require extremely complicated treatment and management to successfully isolate them from the biosphere. This treatment process is usually followed by a long-term management strategy involving permanent storage, disposal or transformation of the waste into a non-toxic form.
Advantages And Disadvantages Of Nuclear Energy
Every innovation by mankind has its own set of advantages and disadvantages. In this part of the blog, I would be explaining the advantages and disadvantages of nuclear energy.
Advantages Of Nuclear Energy
The advantages of nuclear energy are as follows:
- Low Cost: Setting up a nuclear power plant is quite expensive. It is relatively cheaper to produce energy from nuclear sources of energy. Nuclear power plants have low operating costs. Nuclear power doesn’t experience the same kind of price fluctuations as traditional fossil fuel energy sources like coal and natural gas do. This is quite advantageous as the price of nuclear energy can be predicted well into the future. It is anticipated that the price of nuclear energy would remain low and would reduce even lower in the future due to technological advancement.
- Most Reliable Energy Source: Nuclear power plants can run 24 hours a day and 7 days a week. These nuclear power plants can operate for longer stretches and refuel every 1.5–2 years. Solar and wind energy depend upon the sunlight and wind speed respectively but nuclear energy on the other hand has no such restrictions.
- Zero Carbon Emissions: Nuclear power reactors do not emit any carbon dioxide into the atmosphere. This is a very huge advantage of generating power from nuclear energy as compared to the energy from conventional fossil fuels which emit tonnes of carbon dioxide to the atmosphere. According to a study by the Nuclear Energy Institute (NEI) of the USA, found out that nuclear electricity production prevents 528 million metric tons of carbon dioxide from being emitted into that atmosphere annually in the USA.
- High Energy Density: It has been estimated that a one-inch tall uranium pellet can produce energy equivalent to that produced from 17,000 cubic feet of natural gas. It is also equivalent to the energy produced from 120 gallons of oil or 1 ton of coal.
Disadvantages Of Nuclear Energy
The disadvantages of nuclear energy are as follows:
- Environmental Impact: Despite nuclear power plants release zero carbon emissions, they always tend to have some amount of negative impact on the environment, especially while mining the nuclear fuel and water discharge from the nuclear power plant. Uranium is used as a fuel in the reactors of the nuclear power plant. Uranium mining releases harmful substances like radon and arsenic. Those staying close to these mines have faced serious health complications. For example, the Navajo Nation in the USA is known for its Uranium Mines. Many people in this region have died of kidney failure and cancer caused due to uranium contamination. Nuclear power plants are known for being one of the major cause of thermal pollution. Many nuclear power plants are located close to a body of water, like a lake or the ocean. These power plants use the water from these water bodies as cooling water to condense the steam generated in the power plant. This process causes the cooling water to increase its temperature and then released back into the body of water. The water that is released back into the water body is approximately 100 Fahrenheit. This tends to affect the chemistry of the water body it is being discharged into. Therefore, the waterbody becomes inhabitable.
- Water Intensive: Nuclear power plants need a lot of water to produce energy. Noting with deep concern that in the year 2015, the United States consumed nearly 320 billion gallons of water to produce nuclear power. That’s more water being used as compared to that of a coal-fired power plant. In a situation of water scarcity due to climate change, using a billion gallons of water just to produce electricity is not sustainable.
- Risk Of Nuclear Accidents: The safety protocols pertaining to nuclear power plants might be followed strictly, there is always a risk of a nuclear catastrophe because of the unpredictable and uncontrollable nuclear chain reaction in the reactor. When someone says nuclear catastrophe, the very first image that comes to my mind is the Chernobyl Nuclear Disaster that happened in the year 1986 leading to the death of over 4000 to 60,000 people. Even after 3 decades, over 2 million people from Chernobyl are still suffering from health issues due to nuclear radiations. The city of Chernobyl yet remains an abandoned town. Apart from the Chernobyl Nuclear Disaster, we have also heard about the Fukushima disaster in Japan and The Three Mile Island in Pennsylvania.
- Radioactive Waste: Generating energy from the nuclear power plant does not emit any harmful greenhouse gases into the atmosphere but generates hazardous wastes. These wastes are radioactive in nature and must be disposed of properly or else it can affect the lives of many people living in the vicinity of the nuclear power plant. High-level radioactive waste includes the spent reactor fuel and wastes remaining after the spent fuel is reprocessed. The spent fuel is extremely radioactive in nature and must be stored in specially designed pools or containers. The high-level radioactive wastes require extremely complicated treatment and management to successfully isolate them from the biosphere. This treatment process is usually followed by a long-term management strategy involving permanent storage, disposal or transformation of the waste into a non-toxic form. Low-level radioactive waste includes items that have become contaminated with radioactive material during energy production at the nuclear power plant. They include items such as shoe covers and clothing, wiping rags, mops, filters, reactor water, and tools. These wastes are generally stored in the nuclear plant for a temporary time period & after that, they are sent to the waste disposal site. If the low-level radioactive wastes are no longer radioactive in nature, then it is directly disposed of as ordinary waste.
Is Nuclear Energy A Renewable Source Of Energy Or A Non-Renewable Source Of Energy? Is Nuclear Energy A Sustainable Source Of Energy?
While penning down one of my previous blog titled “UN Sustainable Development Goal(UN SDG) Seven & India’s Progress Towards Achieving The Targets Set For The UN SDG 7”, I was a bit confused on whether should I include nuclear energy as a renewable source of energy or not because in the year 2020, 3% of India’s annual power generation is from the nuclear power plants. So I was a bit confused, so I decided to find an answer to whether nuclear energy is a renewable source of energy or a non-renewable source of energy. While searching for an answer online, I found that this debate on whether nuclear energy is a renewable source of energy or a non-renewable source of energy has been going on for decades. Therefore in this blog, I decided to answer this question from my perspective.
Before answering whether nuclear energy is a renewable source of energy or a non-renewable source of energy, one must understand the meaning of renewable source of energy and non-renewable source of energy. Renewable energy is produced from renewable resources that can be replenished by natural processes during the human timescale like sunlight, wind, rain, tides, waves, and geothermal heat. On the other hand, non-renewable energy is produced from non-renewable resources like coal and crude oil which take millions of years to replenish.
The debate on whether nuclear energy is a renewable source of energy or a non-renewable source of energy has been happening for decades. Nuclear energy is a non-renewable source of energy. It's because the fuel used in the nuclear reactors (ie radioactive elements like Uranium and Thorium) has a finite life. The more we continue to mine uranium from the Earth, the uranium resources available would continue to deplete. The experts say that that there are about 200 years worth of uranium available considering that our nuclear energy production rate remains constant. If our demand for nuclear energy increases in the future, it is anticipated that our uranium resources would tend to deplete and might cause a problem in the future. Therefore, Nuclear energy is a non-renewable source of energy.
Despite there is no greenhouse gas emission from the nuclear power plant, while considering the thermal pollution & radioactive waste from the nuclear power plant, the negative effects on the environment due to the mining of Uranium, excess water usage by the nuclear power plant and risk of nuclear catastrophe makes nuclear energy quite an unsustainable source of energy.
Conclusion
As a concluding remark, I would like to say that
Nuclear energy is a clean source of energy provided newer high level safety and waste disposal protocols are followed while handling the radioactve wastes. The nuclear power plants must aim towards reducing their water consumption to produce power with newer technological modificaltions in the nuclear power plant setup. The thermal pollution from nuclear power plants makes them harmful to the environment rather than being eco-friendly.It is not a renewable source of energy and its quite an unsustainable of souece of energy.If nuclear fusion is brought into reality, then we can call nuclear power plants as a sustainable source of energy and can sustain us for the foreseeable future.The sustainability aspect of the nuclear power plants can be improved with technological innovations in the near future. Its always better to see nuclear energy being used for the welfare and the economic prosperity of the country rather than using it for warfare.
