Our Journey to Nuclear Fusion — How I See It

First off, let’s agree on one thing — energy production is hard, expensive, and sometimes dangerous and harmful.

Every time energy production is discussed, a few things remain constant:

• Generating energy is inefficient and results in a lot of loss.
• Energy production has not changed much in the past 100 years. Sure, we have made advancements in nuclear fission, better high pressure steam turbines, but in the end, the goal is still the same — use some sort of fuel to heat water, create steam, and spin something.
• Grids have next to no energy storage capability, so any energy that is produced, must be used instantly.
• Some forms of energy production generate harmful by-products such as nuclear waste, pollution, toxic chemicals, etc.
• Even the largest power plants can only generate a faction of the energy needed for a large city or other major energy consumer.

What if there was a better way?

Enter, nuclear fusion.

Nuclear fusion sounds like something straight out of science fiction, and it is. Basically, nuclear fusion aims to re-create a miniature sun — on Earth. This may sound far-fetched and like something we won’t accomplish until the next 100 years, but surprisingly, this technology is achievable.

Let's first take a look at how fusion energy actually works.

Unlike a typical nuclear fission reaction that powers most nuclear reactors now, where atoms are split and energy is produced, fusion energy does the opposite — it fuses atoms together to create a heavier product. Usually, atoms of deuterium (also called heavy water) and tritium (found in the atmosphere, breeder reactors, and other fusion reactors) are combined and produce helium, tritium, and massive amounts of heat and energy in extremely hot plasma (~150 million degrees C). The reaction does not produce any harmful radioactive materials, toxic waste, or any other non-useful by-products. This makes fusion the ultimate green energy source.

With nuclear fusion, the possibilities are endless — everything from fusion powered spacecraft to bases on other planets powered by fusion. Not to mention, nearly unlimited power here on Earth.

Inside of a fusion reactor with superheated plasma.

So, if fusion is so great, why don’t we have it yet? The answer is not so simple.

There are three main problems right now.

• The conditions inside a fusion reactor must be just right. This is one of the benefits of what makes fusion extremely safe, however it also poses a technical challenge. A reaction cannot start and be sustained unless the conditions in the tokamak chamber (the doughnut shaped chamber where the plasma is) are precisely right.
• Lack of tritium. Since fusion is still under development, and a reaction so far has not been sustained long term, we do not have a large supply of tritium. There are also only a handful of breeder fission reactors that actively produce it. (This is why the price of tritium at the time of writing is 30,000 USD per gram).
• Problem number three is not widely talked about, however it may be one of the most important aspects of energy production from fusion energy. That problem is what do we do with the actual plasma and how do we convert it into useable energy? Hint: we don’t use it to make steam.

Now, anybody can state the obvious problems and say that fusion energy is a moving target that's “always 15 years away”. I however, am trying to bring solutions to those problems.

Let’s explore the solutions one by one.

Starting with the chamber conditions problem. At the time of writing, the record for the longest sustained fusion reaction is 6 minutes and 30 seconds. This is actually a good start, but we will need a self-sustaining reaction that can run indefinitely in order to highly efficient fusion power plants. There is actually a second problem to this as well — power. As you can probably imagine, heating anything to 150 million degrees C takes a lot of power, and even though the current reaction was sustained for over 6 minutes, the reactor still had net negative energy production (meaning, it only consumed power, not produced it — not what you want a power plant to do).

So how do we make the reaction sustainable? We first need to understand what actually happens in the reactor. The chamber walls are lined with extremely powerful electromagnets that manipulate the plasma soup inside the chamber and control the flow of this plasma. This process is called magnetic confinement. It is through the extremely precise manipulation of the magnetic field that the conditions for sustaining a stable fusion reaction are maintained. The problem is that currently, no computer model or machine learning scheme exists to precisely control the field. This is perhaps the main reason as to why we do not have sustainable fusion right now.

So how do we fix that? There is no one best solution right now, but one solution I have considered is measuring the conditions of the plasma and the chamber, and using a supercomputer or HPC cluster solution to run neural networks that can be programmed to extrapolate the chamber conditions and provide real-time corrections to maintain stable magnetic confinement. We can then use those models to build up better and better correction algorithms and even adapt them to various models and types of reactors.

It is also imperative that these processes not be proprietary, but shared with the rest of the energy industry to enable continuous improvement. In order to advance humanity and meet our energy needs, we need to get of the mindset of intellectual property ownership and greed.

The next problem to solve is the lack of Tritium. The prices for tritium have gone up exponentially in the past few decades, and will continue to rise unless a sustainable solution is found. The problem that unlike deuterium, which can be extracted out of regular seawater, tritium is very rare in the environment. Currently, there are a handful of nuclear power plants that have systems designed to capture the tritium that is emitted by the various nuclear processes. This however, is not nearly enough to run even a single fusion plant economically.

The way to solve the tritium scarcity problem is obvious — we create more of it. We can do this in two ways.

The first is simply by not wasting it. There are currently many different types and models of fusion reactors. Some of these have chance to become the sustainable type, and others that have no shot at all. We need to limit the amount of new fusion reactors and concentrate our efforts on the projects that are currently close to developing sustainable fusion. This will not only save both tritium and money, but will also add brainpower to projects that are close to a breakthrough.

The second is more technical and has to do with the way tritium is produced by the actual fusion processes that consume it. When a fusion reaction happens, a good amount of tritium can be produced as a resulting by-product. The problem is capturing all that tritium. I may have a solution. In a typical fusion reactor, there are blankets of tritium absorbing material. We need to urgently improve upon the design and cover the entire reaction surface with these materials. The technology to capture tritium already exists. The current problem is cost of extending the tritium absorbing blankets around the entire surface of the reactor. I do believe, however that the investment to make this happen will be significantly less in the long run than letting our supply of tritium run low, and that it will motivate fusion researchers to come up with a sustainable solution. Nobody said this was going to be cheap, but in the end, it will pay for itself hundreds of times over.

Finally, we get to the third problem — what do we do with the plasma and all that generated energy? The typical power plant designer would say, “just build a giant tea kettle with spinning turbines”. No. We need to get out of the mindset that our energy needs can be met with a spinning hulk of metal that is pushed along by steam. This isn’t the 50s and steam is not the solution to every power generation problem. Now that the rant is out of the way, let’s take a look at how to properly capture energy from a fusion reaction.

This is where things get a little complicated. This solution does not focus on the lossy conversion of one state of matter to another state of matter (water to steam), but rather on how we can extract the energy itself out of the fusion reaction.

For this solution, I am building on the work conducted at NASA on a process called direct energy capture. (I call this revised process “native energy capture”).

This diagram shows one of the processes for direct energy capture. Basically, the goal is to convert the kinetic energy of the charged particles emitted by the fusion reaction into electric potential. Let’s break down how it works.

• The fusion reactor creates charged particles in the plasma.
• The plasma is filleted and syphoned off to a capture chamber (selective leakage).
• The chamber is lined with supermagnets that control the flow.
• Ions strike the electron collector that steals electrons from them (increasing the charge in an already charged system).
• The chamber is cone-shaped which beds the plasma stream.
• The stray electrons with the wrong charge are defected.
• The potential gap between the Ion Collector and the Electron Collector Grid is widened and we have positive current flowing onto the Ion Collector and negative current flowing onto the Electron Collector Grid.
• This current flow becomes the electric power that we are producing.
• And boom! Energy! No turbines or high pressure steam required.

Granted, this currently has only been tested in lab environments, and there are some engineering challenges to overcome, but this is a very promising energy generation system, even in its early stages.

We still have much work to do, but fusion energy as a sustainable energy source is closer than we think.

Thanks for reading!