The Nuclear Fusion Fantasy

At the bottom of 2022 there was a key piece of news that probably went overlooked by many … the National Ignition Facility [NIF][1] in California achieved one of the biggest scientific milestones to date … the ignition condition for nuclear fusion.

So, what is ignition?

Ignition is defined as the state where the nuclear reaction becomes self-sustaining – also the point where the reaction produces more power than it takes to get going … the Q>1 state. [2]

[The Crowd goes wild] so, … that’s it then … its done, we’ve now got fusion. Its easy street and “reversing climate change” from, here right?

Well … not so fast, the ongoing nuclear and engineering challenges are plenty.

Before I go on, I want to make it clear that when it comes to energy I have my bets placed elsewhere, and even though some things should be done for nothing less than to achieve the milestone or because its unbelievably cool … fusion looks more and more to be a fading dream when it comes to being a source of energy for mankind.

That done, lets take a peek at this amazing scientific feat, and why nuclear fusion is no closer to reality today than it was ten years ago.

Let’s Run some numbers.

The current achievement at the NIF is the definition of experimental.

We have to remember the NIF is research project, not an industrially mature facility. They take about 1 shot per day. An industrial facility would require ten shots per second … an increase to 864,000 shots per day.

The extreme perfection of the fuel pellets results in only 1,500 being produced per year. 90% are rejected due to imperfections.

Without using specific units, the reaction itself offers a Q = 1.5 [3], 3 units of energy out for 2 units of energy in.

That also neglects the 300 units of energy to power the entire facility. The entire reason for this article is because Q got above 1. Q needs to get closer to 150 before things get really interesting.

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Getting Energy Out

When it comes to getting energy out of an energy generating device, engineering nailed that little problem during the first industrial revolution.

Spin the Wheel! Energy production is deceptively simple.

Commonly, make fire, boil water … spin wheel!

Everything since the first boiler is just an improvement on the industrial kettle, the only thing that has changed has been the fuel source.

Sure, we have Wind and Solar (Photo-Voltaic) but when it comes to something you can depend on, coal, oil, even nuclear energy all involve super heating water to the point where it can do mechanical work.

But how the hell do you get energy out of a plasma that comes in at 5, 50, or 100 Million Degrees?

Presently there are different reactor designs. Some use magnetic confinement, cusp confinement, or inertial confinement. These plasma’s need to be confined because there is no way to stop the container from vaporizing if there is a plasma leak.

So how do we get the energy out?

When it comes to magnetic confinement, magnetically neutral neutrons will fly out of the plasma to the reactor walls. Those sub-atomic impacts will heat the reactor and fuel blankets which then … will heat water, to turn the wheel!

For cusp confinement [4], heavy isotopes will have their energy stripped from them through direct conversion – a fancy name for a magnet which slows them down and converts their energy into electricity.

For inertial confinement … for a Deuterium-Tritium [DT] reaction, we should be looking at the neutron-water heating methodology, but with a containment chamber as complex as the National Ignition Facility, I for one cannot see how the reaction chamber itself could survive long term fusion reactions.

And as we go further, below, not all energy will go to boiling water!

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The Issue behind Nuclear Fuel

Nuclear fuel is packed with energy. Unlike chemical reactions which gets the energy from the bonds between atoms, nuclear gets its energy from the reduction of mass into pure energy. But that doesn’t mean you can get any sort of fuel to power your reactor.

When it comes to ‘common’ Uranium [U] fission-based reactors, the key fuel of interest, Uranium-235 makes up only about 0.72% [5] of Uranium. Nearly all of the rest of it is U-238.

When enriched to 3-5% you get energy grade fuel. [6] But thanks to the properties of U-238, it can become Plutonium-239 [Pu-239], which can not only be very useful for the purposes of getting energy … well its ‘useful’ for other things too!

As Marvin the Martian said … ‘Ka-Boom’

Fusion has its inverse issues. Just like Fission there is more than 1 reaction that can be zeroed in on. But the most common type is the DT reaction.

Its common for people to talk about Fusion offering endless and limitless power from seawater, but that’s very simplistic … and wrong! Although Deuterium (heavy water) is abundant, tritium is not.

Actual estimates of tritium reserves on earth are in the range of about 20kg (44.4lbs) total! Hardly limitless power.

But the plot thickens.

We can get more tritium, by ‘breeding’ it within lithium blankets [7], that would line tokamak (magnetic confinement) style reactors.

Now doesn’t this sound very similar to what happens with Uranium and Plutonium? It does to me!

Carbon free doesn’t mean Green!

There is no term as over used as ‘green’

Nuclear isn’t green, nor is it clean … its just better than present alternatives.

No Matter how much carbon nuclear might avoid in future, there is nothing that can do away with the nuclear reactions that not only provide the ‘limitless’ energy fusion promises, but also the same process that produces the nuclear waste that will inevitably need to be dealt with later.

Carbon might be one thing, but irradiated reactor vessels are another.

The Fusion Endgame.

So, with all of the scientific and engineering challenges, what’s the endgame?

Frankly I can’t see it! in fact, it just doesn’t make sense to see it!

Firstly, when we want a new power plant, we just go off and get a gas-turbine, and you have a new plant within 1-3 years.

The next thing is that a turbine can be shut down and maintained by qualified and skilled workers on a regular schedule or even an irregular one, where turbines on stand-by can be quickly brought up to operating conditions in the event of failure elsewhere in the plant or network.

While still ‘hours’ before the dawn of fusion (if we get there), fusion just has too many obstacles ahead of it. Firstly, Fusion isn’t clean. Fission isn’t clean. No amount of carbon metrics can hide the fact that components damaged by nuclear reactions at the atomic level need to be handled with procedures that may not have even been created yet. Nuclear waste is a problem no nation has solved yet.

There is the issue of fuel, and how it needs to be produced. There is the issue of dealing with exhaust isotopes, not to mention what happens if a reactor shuts down for any one of a number of serious technical issues.

Delicate and Fragile

At this point in time, Fusion is fragile!

Harnessing the power of a star within a machine is not merely an achievement that should be pursued for nothing less than the scientific breakthrough, it should be done because it’s the coolest thing we’ve ever done.

But once we have, can anyone honestly suggest that fusion reactors would become cost effective enough to become common place within the industrialised world?

Can anyone suggest that if reactor 3 malfunctions, reactor 4 will be ready to go to replace the lost production?

Even now where a generation of children are being scared ****less about ‘the two C’s’, nuclear  reactors aren’t the solution. They produce waste, a waste that lingers. Is fusion any different? Does it genuinely offer a better future?

I dare say that answer would be, no!

Nuclear Fusion has been an idea since the 60’s … over 80 years in the making. That makes it the most expensive, the most complicated, most researched kettle in human history. Don’t get me wrong … it’ll be cool when we achieve it. but when will that be?

It was 20 years, 50 years ago? My guess … give it about 20 years!

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#industry #energy #nuclear #fusion #engineering

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