Viewing a single comment thread. View all comments

[deleted] t1_j07nhnm wrote

Reply to comment by jrkib8 in [OC] Cost of Carbon Zero - Historical Look At U.S. Funding of Fusion Energy by Metalytiq

There's really no comparison. Fusion reactors have to withstand 100x the heat and 1,000,000x the neutron Flux as fission reactors. No materials exist which can actually withstand that and there's no clear path forward given the laws of physics. Fission is actually laughably easy. You literally just put enough uranium together in the right geometry and it gets hot. I could make a fission reactor in my basement if you gave me some enriched uranium to fuel it.

1

jrkib8 t1_j07wsg6 wrote

There are literally actively used methods for material confinement. Most common are magnetic confinements like tokamak and Stellarator reactors. New methods using beryllium blankets by ITER are shown to be effective. Their two problems are they currently need to be actively cooled which eats away at the energy input/output ratio and they contain natural amounts of Uranium, some of which is U-234 and radioactive requiring hazardous disposal at their end of life. Not as serious as.apent nuclear material disposal from fission reactors, but still a major drawback.

There are also companies with successful experiments fusing deuterium and H-3 in lieu of tritium as tritium is costly to produce. Allegedly, this method doesn't require confinement. Since the products are ionized, it actually uses the reactive expansion to power magnetic generators in lieu of heating steam turbines.

But the NIF that just released their announcement doesn't even use magnetic confinements, rather an inertial confinement (ICF) reactor. This means the confinement times can be improved linearly with density of the fuel and it only requires about 10% of the mass of the fuel to reach temperature sufficient for plasma, which also allows for longer reactions. ICF research is way more immature than MCF so it has always been assumed that MCF would be the breakthrough. That's what makes this such an event is that ICF beat MCF to the finish line creating more energy output than input.

Lastly, they didn't just have an experiment with miniscule energy that could only be detected with instruments. They created 3.15 mega joules. That's 875 watt hours. That's enough to power a TV for a day and well beyond enough to prove their confinement technology works

3

[deleted] t1_j07zef4 wrote

Yeah, but they used 300MJ to produce those 3MJ. This whole calculation is just a joke. And the containment method worked.. for a trillionth of a second. IRL the expectation is to contain for 60 years with less than 1 in a million chance of failure.

2

jrkib8 t1_j081y4y wrote

That 300 MJ was to start the reaction, you don't need to continually pump in 300 MJ. Scaling this up by like 1000x and you surpass that one time input. And the scale would likely need to be far higher for commercialization.

Nobody is saying we're there yet, but to deny how remarkable this breakthrough is, is pretty short sighted. It doesn't mean we decommission any existing fission reactors or even stop planning their construction. It does mean that if $38 billion can produce a net positive (and yes this proved net positive by all practical definitions) reaction, any government subsidies or research into hydrocarbon derived fuel needs to be phased out. That's $20 billion annually for oil alone in the US. God knows how much towards corn for ethanol. This announcement justifies a substantial amount of that phased out and put towards fusion.

2

[deleted] t1_j0865uk wrote

I don't think you understand how thus technology works. There's no way to actually scale it up 1000x without putting 1000x as much energy in to achieve ignition.

1

jrkib8 t1_j0868xo wrote

And you do?

1

[deleted] t1_j086lxi wrote

Yes, it's very simple. The lasers impart an insane amount if energy on a tiny area creating the conditions necessary to achieve fusion. Just think of it like using a spark plug to ignite fuel in your cars engine.

1

jrkib8 t1_j087bd4 wrote

Anddd? That amount of energy scales up by 10% with mass as.only 10% of the material is required to turn into plasma to start the reaction, as I've stated. Increasing the density lowers the amount of energy required, as I've also stated (and cited).

1

Brittainicus t1_j083sof wrote

/s? We hit 150% return for fairly instantaneous reactions now. We generally are expecting to do fusion sort of like a combustion engine with many short burst of on and off. If we can get a few seconds of sustainable reactions we looking at many orders of magnitude returns.

We broke even last year, it was pretty big news and all this fusion post is in response from latest break through.

1

[deleted] t1_j085dc4 wrote

No, we got 1% return in reality. It's only 150% in theory if you assume no loses which obviously isn't real.

1

turtle4499 t1_j07zc95 wrote

No one has ever achieved a fusion reaction (in a reactor not a bomb) that produced net positive energy. I dont understand why we are investing in this when we can do fission right now. Most nuclear waste can be used by different reactor types to recycle it. The very small amount left over that can be stored by digging a fucking hole.

1

jrkib8 t1_j082mxt wrote

I fully support continual use and future investment increases into new fission reactors. But having an "if it ain't broke don't fix it" attitude is laughable when you have Chernobyl, Fukushima, and 3 Mile Island staring you in the face. And don't pretend it's just digging a hole for disposal. Simply transporting spent fuel is an immense cost

1

turtle4499 t1_j084zju wrote

https://twitter.com/skdh/status/1602907470133100547

Fusion reactions arent even remotely close to viable.

You can assemble different reactor types in close proximity, which has never been done, and eliminate 99% of nuclear waste. Its never been done because we dont build them with this intended we just yeet the stuff into the ground.

1

jrkib8 t1_j085egg wrote

Her next statement is that commercialization is decades away, which both her and the announcement agreed with.

And thanks for literally ignoring the entire comment you replied to

1

jrkib8 t1_j085ul4 wrote

Her next statement is that commercialization is decades away, which both her and the announcement agreed with. Nothing contradicts my statement.

Also, I have cited nearly every claim I've made and you have not. We're not equally discussing this in good faith. Pretending fission is harmless is a joke. It's worth the risk IMO, but stop downplaying actual nuclear meltdowns

1