Introduction
Nuclear fission and nuclear fusion are like polar opposites - fusion involves the collision and fusing together of particles, so fission would be...? The splitting of the nucleus into smaller nuclei. Imagine a big Iron Man (nucleus) that splits into two smaller Iron Men (nuclei). Okay, I agree - this is difficult to imagine so I’ve put together an example below to help you understand it better.
Figure 1: Fission Iron Man VS Fusion Iron Man
Do you guys remember neutrons? The neutrally charged particle, doesn’t favour positive or negative charges. Fission occurs when a neutron slams into a larger atom, forcing it to split into two smaller atoms, which are called fission products. However, additional neutrons are also released that can initiate a chain reaction, meaning that fission continuously goes, and hence it is much easier to sustain the fission reactions.
When each atom splits, a tremendous amount of energy is released. In nuclear power plants, the energy released by fission is used to heat water into steam. This steam is then used to spin a turbine to produce carbon-free electricity. To release the energy, Uranium and plutonium are most commonly used for fission reactions in nuclear power plants because their fusion reactions are easy to initiate and control.
Now with all of this information, why are we looking towards fusion even though fission works well? Firstly, fission products are radioactive materials that are thrown into the environment; even if there isn’t carbon dioxide being produced, these radioactive materials are still harmful. Secondly, uranium and plutonium fuels are limited in supply and will eventually run out. So currently, we're in the middle - Fusion is too complex to achieve as of now and fission has a negative impact on the environment.
Energy Binding curve
First, let me explain a few terms - Binding Energy is the energy required to break a nucleus into its constituents.
Figure 2: Binding energy ’breaking’ the Nucleus
Expanding on the breaking of a nucleus part : From figure 2, you can see how a nucleus, when provided with sufficient energy (binding energy), it can separate into the nucleons (either a proton or a neutron) that make the nucleus. Hence, the breaking of this nucleus into its constituents means that it separates into individual protons and neutrons.
Higher the binding energy per nucleon suggests that it requires a higher amount of energy to ”break” a nucleus, but this also means that the nucleus of this specific element will be more stable. Whereas lower the binding energy would mean that is less stable. To understand this better, think of a chair (nucleus) on which you exert a small force (binding energy) and it breaks into pieces (nucleons) - that would basically mean it’s less stable doesn’t it. If a chair can withstand a larger force, then it would be more stable to sit on. Same logic for the binding energy.
Now, in the graph (Figure 3) itself binding energy per nucleon would be the energy divided by the number of nucleons as the y-axis (the energy required to separate one proton or one neutron) and atomic mass is the x-axis.
These are the basic differences between the two processes and yes the energy aspect for fusion is extremely attractive but then it’s extremely difficult even with the brightest minds on the planet - and Tony Stark did it all by himself....
The development of a fusion reactor started in 1938 and it’s been 83 YEARS since then and we still haven’t been able to successfully develop a fusion reactor. On the other hand 1945 was when the first atomic bomb was made using nuclear fission and in 1955 a successful nuclear power plant was made powering Arco, a town of Idaho. In just 10 years we went from bombs to power plants - 10 YEARSS ! . A fusion reactor still hasn’t been made, and well Tony Stark just creates one in a day.... 1 day VS 83 years, well that seems realistic. Now let’s talk about some cashhh
There’s a model called DEMO2 that refers to a proposed class of nuclear fusion experimental reactors that are intended to demonstrate the net production of electric power from nuclear fusion. So we could see this is as a practice before the final game (actual fusion reactor). I’m going to share with you the costs for this specific model in 2015.
The total investment cost was 8525 million dollars = 8.5 billion.... If this was someone’s net-worth, he or she would be around the 294th richest person in the world ranked by Forbes.. That is a lot of investment money just for a model.
Figure 3: Comparing costs of different energy resources
Now there’s isn’t a massive difference in investments between fission and fusion but the key difference is that for fission these investments are for working power-plants, whereas for fusion it’s mainly R&D(research and Development)
For R&D the world’s nations are currently spending more than $1.5 billion annually (about $600 million in Europe; $400 million in Japan; $230 million in the United States; a large amount in Russia; and smaller expenditures in Australia, Brazil, Canada, China, India, Korea, and so on).
But there is progress, we’ve come a long way in nuclear fusion but the only problem is more money is needed to lessen the time taken to achieve a working fusion reactor. There’s always this joke that fusion is 30 years away, every single year and of course the more money we spend here, we lose out spending on pressing issues such as poverty, education and healthcare. That being said, fusion could revolutionise the world - not by creating Iron Man, but my creating a sustainable and renewable energy source that doesn’t pollute nor does it produce it radioactive waste - and the energy it produces well you’ll have to see it.
Figure 4: Ratio of fuels for the same energy produced
The main argument here: although a fusion fuel (deuterium and tritium) would be much more efficient, the cost to reach this goal is far too great compared to just using alternative energy sources. The world will change once fusion reactors are built, but we still have quite some time - let me show you what we have achieved so far without Tony Stark.