
Nuclear fusion is 'a question of when, not if' - pseudolus
https://www.bbc.com/news/science-environment-50267017
======
Animats
How's Lockheed's Skunk Works coming along? They're quietly building their
fifth test model of a compact fusion reactor.[1] Using Lockheed's own money.
They plan for ignition at the eighth test model. Once every year or two, they
issue a quiet press release. "The work we have done today verifies our models
and shows that the physics we are talking about – the basis of what we are
trying to do – is sound," Jeff Babione, Skunk Works Vice President and General
Manager.

[1] [https://www.thedrive.com/the-war-zone/29074/skunk-works-
exot...](https://www.thedrive.com/the-war-zone/29074/skunk-works-exotic-
fusion-reactor-program-moves-forward-with-larger-more-powerful-design)

~~~
willis936
No one gives it serious credence because linear magnetic mirror configurations
were found to be a nonstarter for similar reasons that electrostatic
confinement devices are not considered. These aren't arbitrary machines, they
have a real research goal. Skunkworks will never get there with their design
and anyone who looks at their diagrams can tell you that. They also don't
release any design parameters or performance metrics. From the outside it
looks like a method to funnel money into someone's pocket.

~~~
beerandt
I would agree if it was a typical DOD cost-plus contract, but being self-
funded, somebody must have some confidence in the design.

Unless the whole thing is just cover for some other dark money project.

~~~
dfsegoat
Would this fit the bill?

[https://en.m.wikipedia.org/wiki/Lockheed_Martin_SR-72](https://en.m.wikipedia.org/wiki/Lockheed_Martin_SR-72)

------
tompccs
The more times someone feels the need to tell you a particular technology is
inevitable, the more sceptical you should be.

Translation: "we need more money, and will continue to do so for the
foreseeable future".

People working on technologies which are truly "when not if" don't go around
advertising it - they are too busy trying to be the one to profit off it
before the next guy does.

~~~
mywittyname
I agree. If a technology (especially one as significant as fusion) is viable
and the production kinks need to be worked out, then VC-backers are going to
dump money into it in an effort to be first-to-market. The less viable a
technology currently is, the more governments will be paying for the research.

~~~
jasonwatkinspdx
It's not just about viability, it's about complexity and timeline. There's
very little appetite for projects with a 30+ year timeline among private
investment. You can't expect VC backing for stuff like ITER.

~~~
perl4ever
That's an odd thing to say. Ever hear of a thing called 30 year bonds?

~~~
jasonwatkinspdx
Bond's ain't VC.

------
guardian5x
Also interesting is the Wendelstein 7-X experiment, where they build a
stellarator with a unique geometry, compared to the tokamak reactors.

[1]
[https://en.wikipedia.org/wiki/Wendelstein_7-X](https://en.wikipedia.org/wiki/Wendelstein_7-X)

~~~
The_rationalist
Can scientists quantify how much of energy efficiency gains can be made from
current hypothetically suboptimals tokamak geometry?

~~~
willis936
Tokamaks are different beasts than stellarators. They have a toroidal current
induced by a central solenoid (literally a transformer). There are pros and
cons to this. For one, you get a lot of ohmic heating and some focusing
benefits from the current. However, there are plasma instabilities and there
needs to be electrical feedback systems operating with microseconds of
latency. This isn't trivial when dealing with huge currents and voltages at
high inductance. Additionally the transformer can only induce current in one
direction for a finite time (you cannot ramp current to infinity). No one has
figured out how to make tokamaks steady state. The best hope is for runs of a
few days and 80% uptime. It's undetermined if this is "good enough".

Stellarators have traditionally lagged tokamaks in terms of Lawson criterion
performance, but they've also been less funded because tokamaks have
performance advantages. Stellarators are steady state and don't risk the same
number of plasma instabilities. Germany is so confident that it's the right
approach that they built the largest magnetic confinement device ever to test
optimizing for quasi-omnigineity. Stellarators in general are becoming closer
to the mainstream approach and given another 5 or 10 years you'll likely hear
about them as much as tokamaks (at least in terms of non ITER research).

~~~
hedvig
>operating with microseconds of latency.

What are the numbers if you know, of the speed or rate at which plasma can
destabilize?

~~~
willis936
There is a lot of reading out there on the various types of instabilities, but
generally the timescale for these effects are in the microsecond to
millisecond range. I think particles move toroidally in the transsonic range,
which depends on the temperature (which is a gradient from the core). This
would be in the range of 300-1000 m/s in a device with a circumference of a
meter or less (for most science machines made so far). I think it only takes a
handful or orbits for an instability to grow. It depends on how much abnormal
magnetic shear there is. I’m not comfortable saying more.

[https://www.energy.gov/science/fes/articles/zero-
tolerance-t...](https://www.energy.gov/science/fes/articles/zero-tolerance-
tokamaks-eliminating-small-instabilities-they-become-disruptions)

[http://www.ccfe.ac.uk/assets/Documents/POPVOL17p082509.pdf](http://www.ccfe.ac.uk/assets/Documents/POPVOL17p082509.pdf)

~~~
willis936
I can’t edit this post for some reason so I’ll just put my correction here.

I attended a presentation today that, at one point, showed toroidal flow rate
over radius in a 1m major radius device. It ranged from 30 to 100 km/s. There
are many effects operating at different timescales. Turbulence is among the
shorter timescales, making it difficult to simulate and why it is only now the
current focus of many researchers.

------
qubex
Honestly, if the cost of renewables continue to drop and thus make fusion
economically unattractive, why the hell bother? Outside of edge cases (such as
space flight, inaccessible places, propulsion systems, _& cetera_) it seems
that relying on renewables, storage, off-grid/smart-grid solutions sounds
economically and environmentally preferable.

~~~
The_rationalist
Do you know any city that have a majority of it's energy that come from
renewable? Are there any smart grid that really works, that manage the absence
of solar energy the night, the load balancing, etc without just pumping
nuclear energy at the moments where solar/etc can't keep up with the
electrical demand?

~~~
gallexme
There many water dams which feed whole cities

~~~
borkt
Dams are literally terrible in terms of ecological impact. The sooner they are
all gone the better.

~~~
Negitivefrags
The ecological impact of dams is totally local, but the ecological impact of
CO2 is global. If we were to power the entire earth with hydro, the local
damage to ecosystems would be a very small price to pay indeed.

~~~
anoncake
Also, using a fossil plant is harmful, using a dam is not. The damage was done
when it was built.

~~~
jabl
I've seen arguments that some dams where the water level varies a lot produce
a lot of GHG's due to decaying plant matter.

But yes, in general compared to fossils it certainly wins.

------
pseudolus
Just recently Bloomberg ran a great feature article on the International
Thermonuclear Reactor (ITER) in Provence [0].

[0] [https://www.bloomberg.com/features/2019-iter-nuclear-
fusion/](https://www.bloomberg.com/features/2019-iter-nuclear-fusion/)

~~~
kristofferR
CNBC published this great microdoc a few days ago too:
[https://www.youtube.com/watch?v=vPS-
epGPJmg](https://www.youtube.com/watch?v=vPS-epGPJmg)

------
StanAngeloff
Some years ago, likely around 2010, I had the priviledge to visit Culham
Centre for Fusion Energy (it was called UKAEA Culham back then). During my
visit, we were shown around various experiments and after a long evening, we
had the opportunity to attend a Q&A with the staff. The question everyone
wanted to know the answer to was When will it be ready? The scientists and
everyone else involved honestly thought 10 years would be more than enough
time for the technology to mature and find its way into everyday lives.

We are not quite there yet.

~~~
willis936
I’ve heard the argument that it’s a matter of money rather than time. The
physics is such that a big device is a good choice. Even the compact designs
based on high field HTS coils will need to overcome their high power density
in the divertor, that hasn’t come up much yet but it will. So we want a big
device to figure out divertors and breeding and managing instabilities. Great.
We’ll a just make the one, ITER. Well we’re still waiting. If someone with a
lot of money wanted it to happen Right Now they could. You just need a 40
billion dollar c(r)ash program.

~~~
pfdietz
That argument simply assumes money will solve the problems with fusion.
There's very good reason to think it won't.

~~~
willis936
And that reason is? I have very good reason to think it will, as do the plasma
physicists who work on magnetic confinement.

~~~
pfdietz
The volumetric power density of fusion reactors is inherently lower than
fission reactors, because of the square cube law and the need for the fusion
reactor to radiate it's output through the wall of the reactor. This means th
e nuclear core of the fusion reactor will be both much larger and much more
complex than a fission reactor.

~~~
willis936
Certainly a fusion reactor will be a large, expensive, and complicated device.
If it’s going to be directly compared to fission solely on cost to generate
power then yes fission is less expensive. The allures of fusion is its lack of
ability to meltdown, global abundance of fuel, and the ability to choose what
elements get activated. That seems like things that add value to me, but I
don’t think the conversations on funding fusion research are at that level.
I’ve read the transcripts of the US House Subcommittee on Science, Space, and
Technology’s discussions on fusion energy science. It’s clear that the
politicians that represent fusion scientists when the budget is made don’t
have a strong grasp of what the devices are, their potential impact, the
realistic failure modes for these projects, etc. It’s simply a game of
politics.

~~~
pfdietz
You are repeating the hoary old argument for fusion. That argument depended on
it competing only against fission, and making grand nebulous claims that
environmental and safety credits would let it pull ahead, even though it was
otherwise more expendive than fission.

But fission has now lost to renewables, which are now at a levelized cost 3-4x
lower than fission. Fusion's putative safety/env benefits mean nothing now.

The program now is existing on institutional inertia. I don't see this coming
to anything but an inglorious end.

~~~
DennisP
Wind/solar aren't _that_ cheap if you include enough storage to get through a
windless night, and enough overcapacity to get through cloudy winter weeks.

If you're backing them up with fossil, then sure, they're pretty darn cheap.

~~~
pfdietz
You back them up with short term storage and hydrogen. With plausible costs
for 2030 a CO2-free grid optimizes to 0% nuclear.

~~~
DennisP
How about today's costs? After all, presumably you're using today's cost for
nuclear.

It's plausible that, for example, some molten salt reactors currently under
development will be a lot cheaper than light water reactors, so it doesn't
make sense to compare future renewables with nuclear today.

~~~
pfdietz
No molten salt reactor could be available by 2030. Simply resolving material
issues would take at least that long. Proving materials will last X years
takes at least X years.

More importantly, the decision whether to build such a reactor will depend on
decline in costs of its competition in the future, not just now, when the
business case for the reactor requires it operate for 40 years or more.

~~~
DennisP
There are several ways to fix the materials issue, pursued by active projects.
One is simply to replace the reactor core every few years; Terrestrial Energy
and Thorcon are using that approach.

So I'll ask again: how do the numbers look if you compare today's
wind/solar/storage costs without fossil backup to today's nuclear costs? We
can argue until our fingers wear out about what the costs will be in eleven
years, but there are hard numbers for today.

~~~
pfdietz
If they replace the entire core every few years the economics will suck. If
they replace every, say, 7 years, then this will take long enough to
demonstrate that commercial operation will be at 2030 or beyond.

Insisting on looking at today's solar and wind numbers ? Ok, then I also
insist we stick with the numbers for currently available nuclear reactors. You
wouldn't want to hypocritically allow only projections of future nuclear,
right?

~~~
DennisP
Yes, I mean today's nuclear. But for solar/wind I mean what I said above:
enough storage for a windless night and enough overcapacity for cloudy winter
weeks, so it's the cost to actually run a grid on wind/solar/storage alone.

------
flr03
£200m from the UK government to deliver fusion by 2040 looks like a joke. It's
a drop of water.

~~~
blauditore
Why? I know people always mention billions of investment "until we have
fusion". But those things cannot be reliably predicted, guesses are all pretty
wild.

In terms of human working time, £200M roughly pays for 1000 person years of
work, so it's certainly more than "a drop of water". Yes, I know there's more
than salaries and research tools and material are expensive in this case. But
still, imagine 50 people just working on theory and cheap experiments for 20
years; they could achieve a lot.

~~~
bildung
Building a conventional fission plant can easily cost $10B:
[https://thebulletin.org/2019/06/why-nuclear-power-plants-
cos...](https://thebulletin.org/2019/06/why-nuclear-power-plants-cost-so-much-
and-what-can-be-done-about-it/)

$200M is laughable - as is the 20 year plan. I recently reread Summa
Technologicae by Stanislaw Lem. Written in 1961, it also guessed that fusion
will be there 20 years in the future - meaning 1981 :)

~~~
paganel
Hopefully this means that we’ll never achieve nuclear fusion in a practical
way. As far as I can understand this will practically create energy at close-
to-nothing prices, which while it will certainly solve some of our today’s
issues (burning fossils is quite bad) at the same time it will also create a
lot other bigger issues. For example, if you make it energy-free (i.e. price-
free) to cut trees and build highways wherever you want I’m pretty sure the
Amazon rain-forest will disappear a lot faster compared to what’s happening
now.

~~~
pfdietz
No, fusion will not create energy at "close to nothing" prices. It promises to
be extremely costly, actually.

~~~
paganel
Great, then it won’t happen (probably I had mistaken it with something else).
Everything that makes energy less expensive and/or more easily available
creates lots and lots of bad externalities. It’s time we stop believing that
technology and technologic advancement will take us out of this mess, it is
technology that threw us under the bus in the first place.

------
hannob
There's of course not only the question if fusion works, but also how
expensive it will be.

A not unlikely outcome would be that at some point humanity is able to build
fusion plants, but almost nobody will do, because they're just too expensive.
Given the extremely declining price of wind and solar which shows no sign of
stopping this seems rather plausible.

~~~
0xffff2
Wind and solar could be _free_ and we would still have currently unsolved
problems of either storage or clean peaking capacity.

~~~
syrrim
If they were free, then efficiency in the storage would become a non-issue.

~~~
0xffff2
Storage efficiency is already a non-issue in the sense that we still don't
have any real plan to build anywhere near enough of it to enable a pure
solar/wind grid.

~~~
syrrim
Step 1: turn carbon dioxide into fuel

Step 2: burn said fuel for power, when needed

Step 3: profit

------
ZeroGravitas
But still a question of if it will make financial sense. Assuming this
generates heat and drives a steam turbine, solar, wind and battery is likely
to be cheaper than just the steam turbine and the transmission costs, never
mind the fusion bit.

~~~
neuronic
Fusion has the same advantages as fission but the disadvantages are reduced to
a minuscule amount.

CO2-neutral, stable energy generation independent of weather, season, time...
with amounts large and stable enough to be independent of storage solution.

Wind and solar need to be regulated because intensity varies. They are
location dependent (German North produces a lot of wind, but there's no
feasible way to bring it to the South...)

~~~
pfdietz
The biggest disadvantage of fission is its cost and complexity. Fusion makes
these primary problems much worse.

~~~
npo9
I disagree. The biggest (technical) disadvantage of fission is the creation
and use of radioactive materials.

Fusion solves this problem in large part because it uses and produces
significantly less radioactive materials... materials that wouldn’t count as a
security concern.

~~~
catalogia
Fusion reactors turn themselves into radioactive waste. Neutron radiation is
inherent to nuclear fusion and when previously stable non-radioactive
substances are subjected to neutron radiation, they may absorb some of those
neutrons and become radioactive. (This is called neutron activation.) Some
materials are less prone to this than others and that would be considered
during the construction of a production fusion reactor, but even so components
of the reactor would likely become so radioactive that the only way to perform
maintenance on the reactor would be robotics. And when the reactor eventually
needs to be decommissioned, it needs to be treated accordingly.

~~~
tempestn
I wasn't aware of these issues. Did some searching and found this article that
covers them (and others) in detail: [https://thebulletin.org/2017/04/fusion-
reactors-not-what-the...](https://thebulletin.org/2017/04/fusion-reactors-not-
what-theyre-cracked-up-to-be/)

~~~
joey_bob
This talk from the MIT fusion lab lays out some approaches they have for
solving problems in current fusion reactor design, in particular dealing with
the radiation problem in a cost-effective manner.
[https://youtu.be/KkpqA8yG9T4](https://youtu.be/KkpqA8yG9T4)

~~~
pfdietz
The ARC reactor is still unacceptably large and expensive. Its volumetric
power density is still a factor of 40 worse than a PWR primary reactor vessel.

------
The_rationalist
If nuclear fusion can be >= lucrative than nuclear fission is an open
scientific question.

Indeed all solar panels on earth are just capturing byproducts of a fusion
reactor that is the sun. But a fusion reactor at the scale of ITER is not
proved to be lucrative even in an ideal world. I would have hoped that modern
physics would allow to predict with great accuracy how energy efficient would
an ITER-like be in an ideal world where all enginering issues would be solved.
Maybe the proof exist and I'm just anaware of it.

------
jillesvangurp
Once it gets there, it's going to shift to a matter of "how expensive". On
paper, it should be possible to get the cost down but that's many
billions/trillions worth of investment down the line. Meanwhile the amount of
money already planned to be invested in wind and solar is ranging into the
trillions for the next few decades; and most of that is with a clear intention
to get a decent ROI too.

If fusion becomes commercially viable, it will be well after we've gotten rid
of fossil fuels. IMHO this will be somewhere deep into the second half of this
century at the earliest. I might live to see that day but it's going to
require some medical breakthroughs to increase longevity way beyond the
current averages.

Realistically, existing fossil fuel based energy production is already at a
cost disadvantage relative to newly built solar/wind + battery. That gap seems
to be widening through ongoing innovation and also simply economies of scale.
I doubt there will be a lot of fossil fuel based production surviving the next
2-3 decades because of this. At some point it will shift from being
uncomfortably expensive to "this is just plain indefensibly/ludicrously more
expensive; lets stop doing this yesterday". I mean, why would you pay 10-20x
the nominal price of a kwh just to keep some ancient gas plant going.

The only natural brake on decommissioning this stuff is short term supply
constraints for batteries, wind turbines, solar panels, and the associated
support industry. Yes, it's cheaper but buying enough of it for everyone is
just not possible even if you have the cash on hand until production capacity
ramps up which may take a decade or two. We're currently deploying many Gwhs
but we'll need many Twhs. That's 3 orders of magnitude difference. We'll get
there, and when we do, prices will be a fraction of what they are today. But
it will take time.

That in a nutshell is also the challenge for fusion. First we'll need to make
it work and then we need to make it insanely cheap. Like fractions of a
$ct/kwh. That's also the problem for new nuclear/gas plants. It does not make
sense to plan based on current energy prices because they are going to drop by
orders of magnitudes.

------
jacknews
I don't begrudge the research, which I think will yield infinitely more
benefit than the goal.

But it's necessarily the wrong kind of fusion (D-T, unlike the sun's fusion),
and it won't be efficient, or clean, or cheap even when it "works".

The whole endeavor is pie-in-the-sky if you ask me, which reminds me, there is
already a fusion reactor quite nearby that runs 24/7/365(.25), for the next
few billion years. We should find better ways to harness it.

~~~
willis936
Do you have any support to the claim that nucleosynthesis is preferred to D-T
other than nature shows it working in the high gravity regime? Also do you
have any support for the claims of inefficiency or cleanliness? Activated
neutron wall materials have half lives in the ranges of days to 15 years,
making storage less of an issue.

~~~
jacknews
high energy neutrons

will the walls be replaced daily?

~~~
willis936
No. That is why tungsten is the first wall material. High melting point,
structurally strong in high neutron flux, and low activation.

------
Koshkin
If the practical fusion was possible, it would have been achieved by
mid-1960s. (It’s not like Internet, iPhone, or even AMD Epyc would make any
difference.)

~~~
lgats
Improved computer modeling and materials science (high-temp superconductors,
better confinement vessels) are certainly helping us get closer to break-even
fusion.

Practical quantum-computing is being achieved, but wasn't even dreamed of
until the 80s. Have we not advanced in our understanding and scientific
capability since the 60s?

------
The_rationalist
As a reader what I really want to learn is the list of technical reasons why
nuclear fusion / ITER isn't yet working. I would like to see something like a
github.com repository where issues would be technical issues. And I could
follow technical discussions on the issues showing progress or absence of it.

It would really help to quantify how far we are from lucrative nuclear fusion.

~~~
waterheater
The physics of fusion are well-understood. Nuclear fusion was achieved before
nuclear fission. The most common nuclear fusion reaction--the deuterium-
tritium reaction--can be readily performed by research groups across the
world.

As others have mentioned, funding is the main reason why energy production
from nuclear fusion hasn't taken off. The better question is, what isn't being
funded?

Ask yourself: how do you hold the sun in a bottle? The answer is that it's
very hard, but it's doable. You just need to cool the walls fast enough and
make sure the sun doesn't melt the bottle.

Based off this rough problem description, the main issues are the following:

\- Materials: what do you make the bottle out of? Do you know of any materials
which can withstand millions of degrees of heat? Probably not, so you should
look into using magnets to suspend the sun in the middle of the bottle.

\- Confinement: how do you hold the sun? The sun (that is, plasma) reacts to
magnetic fields. Classical designs such as the tokamak drove the plasma around
a donut to keep it confined. Problem there is that you need two magnetic
fields: one to drive and one to steer. Some decades ago, people got smart and
figured out you could design the road in such a way that the car will always
drive straight, so great, you don't need to steer anymore. (This is the main
difference between ITER and Wendelstein 7-X; personally, I think ITER will
turn out poorly, but they'll learn a lot from building the thing...)

\- Reactions: guess what? Your sun emits high-energy neutrons, making the
bottle radioactive. You could use a different type of sun, but those are
expensive and weird or would require you to go to the Moon, which is also
expensive. You figure out you can line the walls of the reactor with lithium
and breed fuel for your sun, which works but isn't perfect. You know other
suns are out there, but no one knows how to build a bottle to hold that sun.

\- Self-sustainment: you put some ingredients in your bottle, shake it up, and
presto, you have a sun. For about ten milliseconds. Problem is, your bottle
got too hot and your reaction creates exhaust you have to scrape out. Also,
the magnets used to keep the sun in the middle of the bottle draw more energy
than your sun makes! That won't do.

Self-sustaining fusion reactors are very hard problems to crack because
there's so many moving parts. The fusion research community has suffered from
underfunding for decades because people wrongfully associate the principles of
Chernobyl with ITER. People don't want their politicians funding more
Chernobyls, and Bob's your uncle. Because the funding has been so low, the
problems which should be solved by now, well, haven't been.

------
pfdietz
When they give up, not if.

Fusion's economic prospects are horrific, even if it can be made to "work",
and this has been known for a long time.

------
cameroncooper
Nuclear Fusion has a really interesting history. There's a good book called A
Piece of the Sun I highly recommend to anyone interested in the subject. I was
surprised on just how much money has been spent by so many countries on
research, how different designs have evolved and just how much politics has
influenced its development.

~~~
willis936
What was the number they stated? I’ve heard “60 billion USD” before, which was
spent by many countries over 60 years. In reality this seems like a small cost
compared to something like the Manhattan Project, which was 23 billion USD
spent over 5 years by one country.

A 25 year availability of a GWe plant (the conventional first gen plants that
have the fewest engineering hurdles remaining) that sells all electricity it
makes generates 22 billion USD in revenue.

~~~
asdfman123
$60 billion USD is probably less than my home city of Houston has spent on
freeways. There was recently talk of a $7 billion plan to widen I-45 north
because people who want to live nowhere near Houston want to get here slightly
faster for work.

------
pontifier
I'm in the process of acquiring a facility in which to build my prototype
fusion reactor. If all goes well, I'll start working on it at the beginning of
2020, and hopefully start testing it within a year.

------
m4r35n357
If we ever get unlimited cheap power we will just use it to dump vastly more
waste heat into the atmosphere. Discuss.

~~~
maxerickson
We have a ways to go before it would be much of a concern.

Solar heating is on the order of 5000 times our current energy utilization
(there's a similar amount of cooling).

Which isn't to say it can never be a problem, just that we are a blip right
now as far as direct heat added to the Earth's energy budget.

~~~
robocat
> Solar heating is on the order of 5000 times our current energy utilization

From another comment: "Mankind's waste heat (~10^12 W) is utterly miniscule
compared to sun's energy delivered to earth (~10^17 W)".

5000 smells bad — imagine that power output concentrated in cites or
production areas — that would be severely noticeable.

~~~
maxerickson
I don't understand what you mean by "smells bad"?

------
Semiapies
So who makes money off of pushing the idea of Fusion Real Soon Now, besides
science writers with looming deadlines?

~~~
danmaz74
Fusion Real Soon Now would mean that we wouldn't need to change our lifestyles
to stop global warming. So, the list of those who would, if not make, at least
not lose money is nearly infinite.

~~~
crimsonalucard
Battery tech needs to improve as well for you to run a car off of fusion at a
total effective cost that is cheaper than fossil fuels.

------
m4r35n357
It always was.

------
viach
Imagine a world where everyone's house is supplied with free, practically
limitless, cheap energy! We could start heating our homes better, finally put
to the end worries about whether we left the iron turned on, power more
sources of light! Hm, but wait...

~~~
Balero
Fusion will never make energy "free". Currently fuel only takes up about a
third of the cost of electricity, the remaining two thirds spread between the
cost of maintaining a grid, and running/building a power station.

So best case you will save about 30% on your bill. A fusion power station is
probably going to be more expensive however, so you will be more likely to
save less than 30% on bills.

------
londons_explore
I thought the matter was settled. Nuclear fusion is 50 years away. Always has
been, always will be.

------
jimmaswell
50 years away as usual.

------
kpU8efre7r
[https://youtu.be/L0KuAx1COEk](https://youtu.be/L0KuAx1COEk)

MIT's Pathway to Fusion Energy - Zach Hartwig

tl;dr: it's a matter of funding

~~~
pfdietz
ARC, the design that would require 40% of the world's annual production of
beryllium to make a single 500 MW(th) reactor.

~~~
kaibee
> Total world reserves of beryllium ore are greater than 400,000 tonnes.[27]

[https://en.wikipedia.org/wiki/Beryllium](https://en.wikipedia.org/wiki/Beryllium)

Seems like there's just not enough demand yet.

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pfdietz
Total world estimated Be resource would make ARC reactors capable of supplying
just 1% of current world primary energy demand (using the USGS estimate of
100,000 tonnes.)

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crimsonalucard
I think the scenario of complete global warming and running out of oil will
play out before nuclear fusion. Realistically.

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thrower123
The answer is always "30 years away"

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pseudolus
Looking through the history of technology the same could have been said at one
time for the automobile, aviation, genetic engineering, etc. The timescale
during which nuclear fusion has been pursued is relatively short and declaring
it a dead end at this early stage is premature.

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pfdietz
It was also said about innumerable technologies that went on to fail. Focusing
just on those success stories is survivorship bias.

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m0zg
You know it's not too far out because Saudis are selling shares in their oil
wealth. When this stuff actually starts to work, the impact on the world
economy will be insane. I suspect this is why it's not being adequately
funded: nobody in power wants to flip over the massive fossil fuel apple cart.

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pfdietz
That's not because of fusion, though.

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aiscapehumanity
Its also not an option. Renewables wont hold up to scaled demand and nuclear
fission is demonized, there is no other viable technological path.

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pietrovismara
You know, we could instead revisit the concept we have of growth. Instead of
growing for the sake of it, like a tumor, we could define what kind of growth
we want and in what direction, and see if it's compatible with our resources.
Do we really need growth or do we need happiness? Once we scientifically
solved major health issues does it really make sense to keep growing
indefinitely? Couldn't we just put a limit to our population and enjoy our
fully automated utopia?

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bpizzi
> we could instead revisit the concept we have of growth

You say 'we' like humanity wasn't 7 billions or so completely autonomous
actors.

This would be a more accurate sentence: '7 billions autonomous actors could
decide to act as one, and the act could be lowering its growth rate'.

You see, it simply won't happen.

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pietrovismara
First of all, it's not 7 billions sentients but rather a handful of
government. Furthermore, humanity at the moment already agrees blindly that
the only way forward is reckless growth, if we all managed to agree on
something without even knowing why, perhaps we can also agree on something
more rational.

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bpizzi
> rather a handful of government.

Which are mostly democracies, or sort of. China, Russia and North Korea apart,
every big population center is governed in a way or another threw a certain
form of consensus.

> humanity at the moment already agrees blindly that the only way forward is
> reckless growth

Again you talk as if humans were a single body. You're not agreeing blindly on
'reckless growth', as far as I can tell, and you're far from being alone in
that case.

Humanity speaking and thinking as one is just a dream (you're free to dream,
thought!).

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ancorevard
If only we would have spent $6 billion on nuclear energy research rather than
on the Large Hadron Collider.

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dlcmh
I’m pessimistic this will ever be able to work. Doesn’t fusion require
tremendous pressure that’s equivalent to the Sun’s gravity? How on Earth are
we going to be able to generate such a pressure?

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retSava
Not a nuclear physicist, but IIRC sustainable fusion requires three factors:
time, pressure, temperature. So far, you can basically choose two of them at a
time, and much research goes into having all three at the same time.

Needless to say, but it also requires loooooots of related research, eg
materials to handle the magnetic flux, temperature, etc etc etc.

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jacknews
I think we can only really do 1 of them, temperature.

Pressures are no-where near the core of the sun (300 _billion_ bar), nor are
confinement times ( _years_ ).

Which is why we use D-T fusion, which is not at all the same as the "clean,
natural hydrogen fusion" in the sun. That whole "clean energy, like the sun"
argument is fake.

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scottlocklin
There is absolutely no reason to think this is true. The sun has the
approximate energy density of a dung hill. The idea that nature will cooperate
and make break even possible at convenient human scales is ... optimistic.
There's basically zero evidence for it.

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DennisP
I'm sorry but that's ridiculous. The sun uses a different fusion reaction.
There is plenty of evidence that with other fuels, net power from fusion is
feasible on Earth.

In particular, the D-T reaction is especially easy, and tokamaks have well-
known scaling laws. The JET reactor in the UK is the only reactor using
tritium and has produced 67% of its input power. In 1999 the JT-60 in Japan
achieved results with D-D fuel that would have hit breakeven with D-T.

With a larger reactor, stronger magnetic fields, and D-T fuel, net power is
the expected result.

(Not to mention, we've already achieved net power at human scales with
thermonuclear bombs, which have far more energy density than a dung hill.)

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jacknews
indeed but D-T is not at all "clean" fusion "like the sun", as is being
claimed for terrestrial fusion.

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DennisP
It's not all that bad though. The troublesome waste from fission is the end
products of the nuclear reactions. With D-T fusion that's just helium.

You do have high-energy neutron radiation, but most of that you're capturing
to breed tritium fuel from lithium. Some of it makes reactor parts
radioactive, but that's not a major waste problem; according to presentations
I've seen from MIT fusion scientists, they'd stop being significantly
radioactive after a few decades.

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jacknews
in practice it will not be so neat. I suspect it will be as polluting as
fission, perhaps worse, as the contamination will be in the superstructure,
not the waste. And less efficient, and even more expensive.

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DennisP
Whether it will be neat depends on the reactor design. MIT's for example
3D-prints the inner core and replaces it annually; it's surrounded by molten
salt with a lot of lithium, and everything around that hinges so it can be
opened up easily. Regardless, the waste won't need long-term containment.

The economics of fusion reactors will also depend on the design. Some look
economically feasible, others not so much. But it's clear that fusion is
_possible_ , contrary to the comment above.

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jacknews
possible, absolutely.

but for sure no panacea.

