If you’ve spent the lockdown period binging on HBO’s Chernobyl, then you must be pretty curious about the concept of nuclear energy- and how it can go wrong. But there’s more to this energy source than reactors that blow up.
The advocates for and against nuclear energy seem to either paint it as the ultimate renewable energy source that will power the future or as the harbinger of the apocalypse. The truth is that it’s a little bit more complicated than that.
But before you dive into arguments about the sustenance of humanity, it is important to be acquainted with the basics- the what, the how, and the why.
What is Nuclear Energy?
The term nuclear energy refers to the energy contained within the nucleus of an atom.
The nucleus is made up of particles called protons and neutrons. Although the nucleus of an atom is very small (around 10,000 times smaller than the size of the entire atom), the particles in the nucleus form 99.9% of the mass of the atom.
This means that the nucleus is comparatively very dense and heavy. So it takes a huge amount of force to hold the particles of the nucleus together, which is why nuclear energy is so potent. This energy can be harnessed to produce electricity.
In the US, 20% of the total electricity generated is from nuclear power. In India, there are 7 nuclear power plants with 22 nuclear reactors, and as of 2019, around 3.2% of total power generation in the country is nuclear.
Recommended blog - What are Top 10 Breakthrough Technologies?
How is Nuclear Energy Produced?
Nuclear energy, in its form that is useful to us, isn’t exactly produced but rather released. Nuclear energy is used for holding together the particles in the nucleus of an atom. That energy can be released, and then used by us for purposes like producing electricity.
For releasing nuclear energy from the atom, two kinds of atomic reactions can be used-
Nuclear fusion is the process by which atoms are brought together or fused to release nuclear energy. Two or more small atoms combine to form a large atom. It is the process that powers the core of the sun, and if harnessed, has limitless potential.
Generally, Hydrogen atoms combine to form Helium in nuclear fusion. But the repulsive forces of two positively charged nuclei are too high, and so the energy needed to cause fusion is too high to guarantee a good deal.
Even though fusion produces a much larger amount of energy than nuclear fission, this method is not yet fully developed and rarely used, due to concerns regarding efficiency, safety and reliability. Nuclear fusion research is a highly promising field and maybe the answer to providing truly renewable nuclear energy.
Most nuclear energy is currently produced by fission.
Nuclear fission is the reaction by which atoms are split apart to release nuclear energy. A large atom is split into two or more smaller atoms. Heavier atoms like Uranium and Plutonium are used for fission.
Although Plutonium has a higher fission rate, Plutonium is hard to obtain. Uranium is the heaviest natural element with 92 protons, and due to the size of the atom, the atomic forces holding the atom together are comparatively weak. This, along with its more manageable reaction rates and better availability as compared to Plutonium, makes it the perfect candidate for nuclear fission.
When a Uranium-235 atom is made to collide with a neutron, it splits into Krypton-92 and Barium-141, and releases two extra neutrons. But the combined masses of the resultant two atoms is less than the mass of the single source atom. This is accounted for when we understand that the missing mass gets converted to energy. (Einstein’s mass-energy equivalence; E=mc²)
Nuclear Fusion vs Fission (Source: Physics and Radio-Electronics)
So we see that to induce fission, we cause a collision between a large atom, like Uranium-235, and a neutron. But if we had to individually cause collisions for each atom, the efficiency of the process would not be so great. Here is where chain reactions come in.
Along with the fission products, two neutrons, in addition to the original neutron responsible for the collision, are also released. These, in turn, collide with other Uranium atoms, and the neutrons released from them cause further collisions, and so on and so on.
Fission Chain Reaction (Source: nuclear-power.net)
Fission chain reactions can be performed in a controlled manner, and nuclear energy can be harnessed. But this cannot be done in any old laboratory. A Nuclear Reactor is used for performing this purpose.
Nuclear fuel undergoes chain reactions inside the core of a reactor.
The energy released from chain reactions are in the form of heat and can be harnessed usually by having it be absorbed by circulating coolant water. The water heats up and generates steam, and this steam can be used to rotate a turbine and generate electricity. Without the water gathering up the heat, the reactor would also be prone to meltdowns.
But an uncontrolled fission chain reaction can be very dangerous. To keep the reaction in check, control rods, typically made of graphite, are used to absorb excess neutrons.
The reactor also has concrete and steel protective layers to contain radioactivity, and also other safety measures to prevent accidents.
For large-scale production of nuclear energy, nuclear power plants are set up. A typical nuclear power plant has a number of nuclear reactors.
Disadvantages of Nuclear Energy
When looking at only the power generating capacity and efficiency of nuclear energy, it looks like the perfect solution to satisfying the world’s power requirements. But when thinking about the adverse effects of nuclear energy, it becomes important to examine long term ramifications, and to also take a long look at history.
Nuclear waste includes radioactive fission products, used fuel, or other materials contaminated by radioactivity. Low-level waste can be disposed of as with other industrial waste, but high-level waste is a different matter.
Radioactive fission products can take a lot of time to decay into stable elements. As in thousands of years. So nuclear waste retains its radioactivity for all that time, and till now no viable method for dispersing its toxicity quickly has been discovered. So that means that high-level nuclear waste cannot be disposed of, but is simply passed onto future generations.
Reprocessing of used fuel can be done to limit waste, but it isn’t done extensively due to cost. Otherwise, nuclear waste of all kinds is cooled, treated, and stored away. Containment of nuclear waste is done by placing them in sealed containers and putting them into underground repositories, for an indefinite amount of time. The effects of such long term storage on the environment are still unclear.
Nuclear Power Plant Accidents
Since the construction of the first nuclear reactors in the 1950s, there have been a number of nuclear power plant accidents of varying intensities. Chernobyl and Fukushima are the most well-known, and most disastrous of them, classified Level 7 on the International Nuclear Event Scale (INES).
In addition to the death and destruction caused by the initial event, a nuclear power plant incident most likely results in radioactive contamination of land around a large radius, making it inhabitable. It also results in long term health effects and increased mortality rates in those exposed to radiation.
Reactors can be damaged by faulty systems, or human negligence or error. Like in the case of Fukushima, reactors are also prone to damage by earthquakes and other such impacts- and are also potential targets for terrorist attacks and sabotage.
Since the Fukushima disaster is only a decade old, it cannot be dismissed as early-stage design flaws in construction. But the improvement in safety measures can obviously be seen in the difference in the number of those affected by Chernobyl in 1986 and Fukushima in 2011. So modern reactors are much more careful and informed about construction and maintenance, and learning from the mistakes of their predecessors.
A nuclear bomb has immense explosive power, capable of taking out an entire city with one bomb, and as an added bonus, continues taking lives for years with lasting waves of radiation sickness.
It is estimated that the combined death toll of Hiroshima and Nagasaki immediately after the bombings were around 214,000. But over the years that followed several thousand more succumbed to radiation poisoning, cancer, and other long term effects of radiation exposure.
A nuclear holocaust remains a recurring theme in science fiction because of its terrifying potential to become a reality. Around 9,000 nuclear weapons exist in the world, under the control of nine countries. The aftermath of the detonation of even one of them would be catastrophic, and would possibly lead to multiple retaliations, and destruction on a scale that we have never before witnessed.
There has been great progress in nuclear arms control since the Cold War when this nuke accumulation first began. But even in the best-case scenario, the goal of a nuke-free world would take at least decades to accomplish, and may even never become a reality.
One of the biggest arguments you hear for nuclear energy is that it is a renewable resource. But that is technically untrue. Although nuclear energy as a source of power could be considered non-renewable, nuclear fuel is not.
Uranium, which is the only nuclear fuel currently used on a large scale, mined from Uranium ore. Which is available in plenty. But it’s not an infinite resource, like sunlight or wind.
Total Uranium supply won't last more than 80 years at the current consumption rate. If nuclear power generation is more widely adopted, that period will further shorten.
Nuclear power plants are extremely costly to build. This is one of the main reasons why nuclear energy is not adopted as hastily by governments.
The high cost is due to several factors. Power plants need a large amount of land, with proximity to a water source. The design and engineering aspects take years, and inputs from a large number of experts. The actual structures to be constructed are complex and need to take into account exhaustive regulations. At the same time, a nuclear power plant is only meant to operate for 40-60 years, and need to be decommissioned after that.
In addition to the high capital costs, when faced with the risk of protests and lawsuits, and the possibility of stalling or even cancelling projects, governments often elect to avoid the risk of undertaking the construction of a nuclear power plant.
Advantages of Nuclear Energy
Although nuclear energy is not a renewable source of energy, it is fitted into the vision of a clean, green, and renewable future. And it has many features that make it an adequate candidate for that vision.
No carbon emissions are produced in the process of generating nuclear energy. Indirect emissions, like those from construction, transport, and so on, are found to be less than that of renewable sources like solar and wind energy.
It is estimated that nuclear energy prevents 506 million metric tons of CO2 emissions annually. In addition, nuclear energy also causes no air pollution in its production.
Recommended blog - Can electric vehicles save the overall environment?
Faced with the need to turn away from fossil fuels, the world is working towards dependence on renewable, green, and clean energy sources. But sources that truly satisfy those criteria, like solar and wind energy, are still greatly unequipped to keep up with the growing power demands of the world.
Large industries and entire cities can be potentially powered entirely through power generated from a nuclear power plant alone.
Take the R. E. Ginna Nuclear Power Plant in New York, with one reactor having a capacity of 582 MW. If the reactor operates at full capacity for 24 hours a day for an entire year, it will generate 5,098,320 MWh. But most reactors don’t operate at full capacity, and in 2017, that particular nuclear power plant actually generated 4,697,675 MWh.
With advances in nuclear fusion technologies, the potential for nuclear power generation just gets higher.
When the wind stops, the windmills stop turning. When the sun stops shining, the solar cells go powerless. Reliability is one factor that sets nuclear energy apart. As long as nuclear fuel is available, reactors can work round the clock and aren't affected by environmental conditions.
Although capital costs are quite high, the operation costs of nuclear power plants are very low. And even considering the entire cost, the payoff is more than enough to justify it.
Nuclear power also does not experience the kind of uncertainty in price tied to availability that fossil fuels do. With advancements in technology, the overall cost of nuclear energy is only bound to get lower with time, unlike oil prices which get higher with time and scarcity.
It’s easy to say that nuclear energy has racked up a body count. But when looking at the data, surprisingly, nuclear energy has perhaps saved more lives than it took. Because pollution, fossil fuel mining, and other side effects of less reliable sources, also cause human fatalities.
A study showed that global usage of nuclear power prevented approximately 1.84 million deaths related to air pollution that would have resulted from burning fossil fuels. It was also projected that nuclear power could further prevent an average of 420 000–7.04 million deaths by the middle of the century.
When looking at the number of deaths per energy unit produced by each type of power generation, nuclear energy ranks last, though it is unclear whether the numbers take into account long term fatalities caused by radiation exposure and the like.
This of course does not justify death, disease, and disaster caused by nuclear power in any way, but does offer a different perspective.
Pros and Cons of Nuclear Energy
Nuclear Energy- Saving Grace or Destructive Force?
We are drawing closer and closer to completely exhausting our non-renewable sources of energy- battles are being waged over oil fields every day. And so the conversation around nuclear energy is, simply, unavoidable.
The terror of nuclear energy lies mostly in extreme predictions and our fear of disaster. Even looking at the concerns over nuclear energy, we can see that new technology is being researched and developed that mitigates each of those concerns. Very recently, China announced its "Artificial Sun" fusion nuclear reactor, which is a great milestone in fusion research.
There will soon be a way to safely dispose of nuclear waste, produce renewable nuclear energy, mitigate the effects of radiation, and prevent reactor meltdowns from ever happening.
But, at the same time, the dangers that nuclear energy poses also cannot be glossed over. The best hope is that negligent construction of power plants and trigger happy politicians would not stand in the way of nuclear power becoming a reliable and efficient source of energy for the world.
Recommended blog - What is Active Solar Energy?