Fusion is the joining of two nuclei to make a single heavier nucleus and it also produces some leftover energy in the process.
It is the opposite of fission which comes from splitting an atom and is used to power nuclear plants. Fusion occurs constantly on our sun, which produces most of its energy via the nuclear fusion of hydrogen into helium.
Fusion energy has two advantages over fission energy which is what we currently use in nuclear power. Fusion doesn’t lead to run off chain reactions the way fission can, so there’s no need to worry about nuclear meltdowns. Another benefit of fusion reactions is that it doesn’t produce the large amounts of dangerous radioactive waste that fission reactions do.
But unfortunately for fusion to occur on Earth, you need a temperature of at least 100 million degrees Celsius. The amount of energy you would need to put in to produce that kind of heat or pressure is much, much higher than what you get out in usable energy.
To have fusion on earth we need cold fusion, a term used to describe the hope that fusion reactions can occur at relatively low temperatures. The idea of cold fusion was once a mere pipe dream, the field was largely written off as pseudoscience the late 1980s.
That all changed when Stanley Pons and Martin Fleischmann reported that their room-temperature electrolysis experiment had produced so much heat and nuclear by-products like tritium that the only explanation was a nuclear reaction. Pons and Fleischmann’s results led to a new wave of cold-fusion experimenting, but no one was able to replicate their heat anomaly. A Department of Energy review later debunked the evidence.
But scientists are still working on making (hot) fusion a viable energy source. Stewart C. Prager of the Princeton Plasma Physics Laboratory called the process of creating viable energy from fusion “a grand scientific challenge.”. Today, fusion reactions occur in doughnut-shaped chambers called tokamaks where gas is pumped into a vacuum chamber and electricity flows through the doughnut’s hole.
The gas becomes charged, to make a state of matter – one that isn’t liquid, gas, or solid-called plasma. Plasma is an ionized gaseous substance that becomes highly electrically conductive to the point that long-range electric and magnetic fields dominate the behaviour of the matter.That plasma is then locked inside the vacuum chamber by magnetic fields, created by massive magnetic coils, in order to imitate the pressure of the sun’s core. Waves are fired into the plasma to raise its temperature, and at around 100 million degrees fusion can occur.
Reaction outputs have come a long way in the past few decades—from milliwatts 40 years ago to 16 megawatts today – but it’s not enough to make it a economical source of energy. One barrier to a sustained reaction, aside from the amount of energy needed to reach such high temperatures, is finding a material that can withstand that much heat for more than a few seconds.
Steve Cowley, director of the Culham Centre for Fusion Energy, says more investment is needed to make fussion possible. “It’s expensive research that can only be done at large scales and nobody sees the need right now.” Cowley says for 20 billion dollars he could build you a working reactor but it may pnot be reliable. That said 25 years ago we didn’t even know if we’d be able to make fusion work. Now, the question is whether we can make it affordable. h