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Raphael Thys
NIF laser preamplifiers — WikiCC
So, you may have heard of this little thing called climate change. It’s no biggie, just the world hurtling towards an apocalypse of rising seas, horrific storms, raging wildfires, deadly droughts and widespread extinction. To stop this Promethean horror from occurring we need to drastically change our ways, and fast. One of the golden solutions is nuclear fusion, a futuristic method of generating abundant energy with no carbon emission, toxic waste or radioactive waste. However, this technology has remained out of reach for decades. But a recent development at the National Ignition Facility (NIF) could change all of that.
So, has NIF bridged the gap to useable fusion power that can save the world?
Before diving into NIF’s incredible leap, we first need to understand what fusion power is, why it so so hard to harness and why it will be so revolutionary.
Nuclear fusion occurs when two atoms come together with such force that they fuse into a single, heavier element and, in the process, release a lot of energy. It takes a staggering amount of heat and pressure to fuse even the lightest element, hydrogen, into helium. In fact, hydrogen fusion is what powers the Sun. But the conditions needed for fusion only exist in the very core of the Sun.
The Sun is powered by fusion — Photo by NASA on Unsplash
We have had the ability to fuse hydrogen in labs for decades now. There are various types of reactors too, like Helion’s magnetic target reactor, Tokamak’s magnetic confinement reactor and NIF’s inertial confinement reactor. But the problem with fusion isn’t getting the nuclear reaction to happen (that step is relatively easy), it’s getting a net gain in energy that is the hard part.
Take NIFs reactor. It uses an astonishingly powerful laser to compress and heat a tiny pellet containing hydrogen. Once fusion takes place, an immense amount of heat and radiation is emitted. This heats up the reactor walls, which is used to generate steam and drive a turbine, resulting in power generation.
NIFs reactor chamber being built — WikiCC
In theory, if a rector was efficient enough, it could make enough energy to power a large city with helium as its only byproduct. This means no greenhouse gasses produced by coal or gas plants, no nuclear waste produced by fission reactors and no vast land use or mega batteries required for solar panels and wind turbines. In short, a fusion reactor would be by far the most environmentally friendly form of power.
However, it is nearly impossible to get more energy out of a fusion reactor than it takes to get it started. The trick is to make the energy used to operate the laser less than the energy extracted by the turbine to get a net gain in power. This has proven almost impossible. Losses in the reactor, like X-ray emissions, fast cooling plasmas and incomplete fusion drags the efficiency down.
But NIF has finally created a ‘burning plasma’ inside their reactor, which could solve this deficit in one fell swoop?
The Sun can sustain permanent fusion as it has a chain reaction happening in its core. The heat from one reaction is enough to trigger another, making the whole process far more efficient. This process is known as a ‘burning plasma’, and it has been infeasible to recreate it in our Earthbound reactors. The plasma cools down too quickly.
This means that for every reaction the NIF does, it needs to fire up its laser. That means the efficiency of the reactor is heavily damaged as the laser, reactor and steam turbine aren’t 100% efficient, far from it.
But somehow, NIF has created a ‘burning plasma’ in their reactor. The heat and energy of the initial reaction cause more hydrogen yet to fuse, creating a self-sustaining, highly efficient chain reaction.
NIF target chamber — WikiCC
This self-sustaining reaction means that NIF only needs to fire their laser once to get multiple fusion events. In other words, way more energy out than energy put in. This is the sort of leap forward needed to make fusion power a practical and useful energy resource.
So, if NIF has solved one of the biggest hurdles of fusion power, why isn’t commercial fusion power coming to the public? Well, it takes a lot more than just a ‘burning plasma’ to get a useable fusion reactor.
Firstly, while this is a monumental step in the right direction, the plasma doesn’t sustain itself for very long. Once all the hydrogen in the single pellet fuses or disperses, it stops reacting. NIF can’t yet feed more and more pellets into the reactor and have them self-ignite. ‘Burning plasma’ only increases the efficiency of a single pellet. It doesn’t make it a perpetual motion machine.
NIF target — WikiCC
Secondly, extracting the energy from fusion needs to be a highly efficient process. NIF uses a Deuterium-Tritium reaction (two types of hydrogen) as it is by far the easiest form of fusion. This reaction releases mainly high energy alpha particles and neutrons, which are difficult to extract energy from. Hence, this high tech facility still needs a steam turbine to make power from the heat generated by the alpha and neutron radiation, which is inefficient.
However, the Deuterium-Helium 3 fusion reaction emits primarily electromagnetic radiation, but is harder to fuse. We can easily and efficiently convert electromagnetic radiation into electricity using electromagnets. In fact, this is precisely what Helion (another fusion group) are doing with their reactor.
But, unlike Deuterium and Tritium, Helium 3 doesn’t occur naturally in any abundance. We can either create it as a byproduct of fusing Deuterium with another Deuterium or letting Tritium decay. This makes Helium 3 complicated and expensive to produce.
NIF massive and efficient laser — WikiCC
But if NIF wants to get their reactor to become useful, i.e. have enough gain in energy high to be worthwhile, they may need to look into technology similar to Helion’s. ‘Burning plasma’ means that the reaction within NIF’s reactor is nearly as efficient as it can be. It is the efficiency of the systems around NIFs reactor that matter now, like the laser and turbine systems.
However, lasers and steam turbines are almost as efficient as they will ever be. So, NIF may need to switch to Deuterium-Helium 3 reactions and replace the outdated steam turbine with the far more efficient electromagnet array to achieve a useful power output.
This is however, speculation. I’m not a nuclear physicist after all and I’m sure NIF have plans to take this incredible milestone and use it to drive us closer to a fusion-powered future.
So we are still a way of fusion power. However, it is our best bet for saving this planet. If NIF can create a useable fusion reactor, it would mean the world’s energy needs could be met without burning coal or gas, making radioactive waste or chopping down vital forests for extensive solar farms. The achievements of these genius scientists and engineers really could save the world from humanity’s ignorance, greed and stupidity. So there is hope that this monumental achievement is a stepping stone towards a revolutionary technology that can save the world.