
Fusion reactors: Not what they’re cracked up to be - waynenilsen
http://thebulletin.org/fusion-reactors-not-what-they%E2%80%99re-cracked-be10699
======
Robotbeat
There's nothing quite like trying to get fusion to work for a while to make
you appreciate how awesome fission technology is.

If we applied even half the cleverness needed for fusion to making better
fission technology, we'd probably be way better off.

...and then there's solar. Why even bother with producing the energy, just
capture it with a very thin solid state device! Just need to automate the
planting of solar panels in the desert, and we could produce all of our
electricity from the Sun. Using just a fifth to a tenth of the land (and much
crappier land that nothing much can grow on) that we use for /ethanol/
production alone.

(Yes, storage is tough, but is getting cheaper, and we can just plant more
solar panels so there's enough power even during cloudy days... Although this
is mostly a thought exercise. The best plan for deep decarbonization by far is
to operate with a mix of clean power sources optimized for high capacity
factor, including at least our current nuclear fleet... They help provide a
reliable baseline which drastically reduces the amount of storage and over-
installation required. That last 20% of power produced by nuclear is worth its
weight in gold and should be protected at least until all fossil power
production is ended.)

~~~
short_sells_poo
How exactly do you propose to get that electricity from the desert to say
Finland?

Furthermore, you need to plaster a vast area in the desert with solar plants,
which brings along all sorts of concentrated security risks. The alternative
is to have many smaller plants dispersed, which results in a big loss of
efficiency.

I'm all for clean energy, but you seem to be handwaving away pretty huge
issues as "thought exercise". Our inability to store energy is not just some
side concern that will go away any time now. There is a reason carbon fuels
are so prevalent - their energy density is far above what we can store in
batteries. Without scalable and high density energy storage, unpredictable
energy sources like solar or wind are much less useful because often there is
no sun or wind at high demand and on the contrary there can be an
overproduction during low demand. Germany already causes serious headaches for
the European grid when it floods the network with electricity on sunny/windy
days. They actually have to pay other countries to take over the extra
capacity.

Solar, wind, tidal etc... energy are all awesome and clean (if we disregard
the land that they take up), but there are many difficult issues that remain
to be solved before they can become a core part of the energy production.

~~~
theptip
> How exactly do you propose to get that electricity from the desert to say
> Finland?

High voltage DC transmission works fine for this problem. All of the
engineering challenges have been credibly worked out and priced
([https://en.wikipedia.org/wiki/Desertec](https://en.wikipedia.org/wiki/Desertec)).
The main problems with this approach are political, in that it requires
massive cooperation between many countries over very long time scales
(decades).

Why is there a security risk with putting solar in the desert? It seems like a
relatively easy to secure location, and solar cells are hardly high value-
density targets for theft or vandalism.

~~~
sfifs
The danger is political risk, not necessarily theft or vandalism. Any
dependency on territory not under your own societal control can be used to
hold you hostage and cannot be depended upon.

Forget the solar farm, easiest is to cut power lines. (explosives?)

~~~
lucaspiller
Europe imports around 30% of its oil and gas from Russia. The pipelines
between the east and west were originally setup during Soviet times.

Given how stable that has been it seems unlikely that a small African country,
who will be getting a big chunk of cash from Europe, would do anything stupid.

~~~
gsnedders
They haven't been perfectly stable, though. We've seen since 2005 a few cases
of oil and gas prices surging upwards as part of the Russia-Ukraine dispute
(in 2005, 80% of all gas from Russia to the EU went through Ukraine).

------
erikgrinaker
Much of the (valid) criticism in this article relates to the deuterium-tritium
fuel cycle. This is the easiest reaction to accomplish on Earth, so most
experimental reactors are designed with this fuel in mind, and we're certainly
having a hard enough time making even this work.

However, I've always considered D-T fusion an intermediate step on the path to
aneutronic fusion, such as Helium-3 or proton-Boron reactions. These avoid
most of the radiation issues, as well as the tritium-breeding problem
(although Helium-3 sourcing presents its own challenge). Since the fusion
products are electrically charged the reactor could possibly also generate
electricity directly, without a steam turbine and the associated energy loss.
Unfortunately, it requires temperatures that are an order of magnitude higher
than D-T (well beyond a billion degrees Kelvin), so we'll need to learn to
walk before we can run.

~~~
VLM
The nice thing about fusion neutrons is you get to control the isotopes, you
have no control over fission waste isotopes.

Some fission isotopes are really icky to deal with, as everyone has heard...

On the other hand if you don't like dealing with cobalt-60 waste at your
fusion plant, simply stop using cobalt alloys in your reactor vessel.

It turns out to be "not that big of a deal" to design a fusion plant where
neutron activation isn't important. The quotes are because nothing is easy in
fusion but as a problem its pretty low on the list.

~~~
FiatLuxDave
This is true. Back at Fiat Lux when we designed our D-D reactor, we intended
it to sit inside a pool of water and borax. Since we didn't need to regenerate
tritium, just absorbing the neutrons with boron was the cheapest solution. As
far as I know, Borax is the cheapest effective neutron shielding known. We
would have liked to have built our vacuum chamber out of purely Al (since
Al-28 has a two-minute half-life), but we went with steel for cost reasons.

Unfortunately, we never made enough neutrons to activate anything worthwhile.
Nevertheless, it is certainly possible to work around neutrons through design
decisions.

------
theptip
I think the four objections here can really be summarized as two:

1) there are energy/fuel losses involved in operating a fusion reactor which
aren't present in other types of power source.

This doesn't seem fatal to me; either we get the losses down low enough that
this system is cost-competitive, or we don't. There's no way to know in
advance where this tech will end up, and it doesn't seem like a reason to stop
investing in R&D now.

2) Fusion as currently designed produces lots of neutrons, so there is the
same sort of waste and proliferation concern as a normal (or fast breeder)
fission reactor.

I think this is actually the interesting one; the international community will
not permit this tech to spread beyond the current nuclear powers if there's a
strong proliferation risk. I hadn't realized that the current design of fusion
plants were basically breeder reactors, and that's very significant; look at
how the theoretically-appealing fast breeder fission reactors have been
hamstrung for a prequel to this fight.

Of course, if fusion gets to an integer factor cheaper than the next-best
source, then it will be hard to keep a lid on this tech, but development is
currently relying on many billions of dollars of research funding from the
very countries that could be turning away from it out of political/security
concerns.

------
shaqbert
Mmmh, some of the claims in that article are debunked in this neat video from
MIT (though over 1h long):
[https://www.youtube.com/watch?v=L0KuAx1COEk](https://www.youtube.com/watch?v=L0KuAx1COEk)

~~~
Xorlev
Which claims does it refute? I'm not able to watch the video, but I'm
interested.

~~~
shaqbert
E.g. the nuclear waste problem: With the right shielding you'll get to
radioactive waste that is much easier to handle and usually decaying enough in
a 60 year time span. As opposed to the millennia from fission products. So
yeah it is a problem, but manageable.

Or the parasitic power consumption problem. Yes, fusion reactors require a lot
of energy to power that magnetic field, the cooling for the magnets, but the
whole point of fusion research is to get an order of magnitude out of the
energy put in, i.e. a G-factor which is > 1\. Right now we don't have a fusion
reactor that manages G >1, but Iter has the potential to operate around G = 5,
and before long some smart kid will figure out a design that gives you G > 10.

The tritium breeding problem. There are indeed some smart solutions like a
FLiBe salt blanket fill. Which also is great at absorbing the neutron "waste".

The nuclear proliferation problem. This is more of a theoretical problem, as
there are way easier pathways to a bomb. E.g. the thorium fuel cycle to breed
a U-233 based bomb is doable even with tech from the 1960'ies.

------
Recurecur
I'm interested in the approach being investigated at LPPFusion, on a
shoestring budget no less.

[http://lppfusion.com/](http://lppfusion.com/)

LPPFusion is attempting to harness hydrogen-boron fusion, which doesn't
produce neutrons, only gamma radiation and helium nuclei (alpha particles).
Both the gamma radiation and the alpha particles can be directly converted
into electricity. There are many potential benefits of this approach, but a
primary one is that with no neutrons, there is no nuclear waste (or
potentially plutonium) produced.

I hope LPPFusion can secure substantially more funding, it's doing more
worthwhile research than the majority currently being done.

~~~
_rpd
There are a whole bunch of options for aneutronic fusion ...

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

~~~
Recurecur
True, but there are many engineering tradeoffs. Any of the listed reactions
involving deuterium produce some neutrons, so those aren't desirable (plus
deuterium and tritium are rare).

Of the other reactions, neither Li-6 or N-15 are readily available, plus
lithium is highly chemically reactive. The proton-boron reaction requires the
lowest input energy (temperature) of the desirable aneutronic reactions, so
it's the hot ticket...so to speak.

~~~
DennisP
Tritium is rare, and has to be bred from lithium, but deuterium isn't the
least bit rare. There's enough deuterium in your morning shower to provide all
your energy needs for a year, and enough in the oceans to last until the sun
goes out.

(Plenty of boron too, though it's not so absurdly abundant as deuterium.)

~~~
Recurecur
Interesting, I'd never really looked into that...perhaps someday we'll figure
out a good solution for thermal neutrons.

------
Robotbeat
(Thinking about the far future, here.) Inertial fusion using Deuterum and
Helium 3 would solve a lot of these problems. Of course, He3 is rare here on
Earth.

I don't think mining the Moon for He3 makes much sense. It's just too rare in
the lunar soil.

Instead, my favorite concept is mining it from Uranus (whose gravity at Earth-
like pressures is actually slightly less than 1g...). There's vast amounts
available at useful concentrations (in addition to deuterium). You'd need a
reusable two-stage nuclear thermal rocket to get it back to orbit, but luckily
there's lots of hydrogen for propellant in the atmosphere (unlike Earth where
that hydrogen must be chemically split from water or methane) and we've built
and tested nuclear thermal rockets before (with more recent NTR designs
achieving sufficient performance for such a vehicle to close). I'm not a fan
of NTR for Earth launch (a lot of cost, plus it actually requires a lot more
energy since all the propellant is hydrogen, instead of a mix of methane and
mostly oxygen), but it would be enabling for Uranus launch.

Here's a concept for mining Helium 3 in Uranus using floating hot-air balloon
mining facilities:
[https://solarsystem.nasa.gov/docs/5.6_Reinert.pdf](https://solarsystem.nasa.gov/docs/5.6_Reinert.pdf)

~~~
DennisP
Another option is to simply breed He3 with pure deuterium fusion; the output
of the D-D reaction is He3 half the time, and otherwise tritium, which decays
into He3 with a 12-year half-life. D-D produces neutrons but at normal fission
energies, not the really high energy of D-T neutrons.

Fusion startup Helion, which is funded by YCombinator, is attempting a hybrid
D-D/D-He3 reactor, saying the combined reaction would produce only 6% of its
energy in the form of neutron radiation.

~~~
dkirtley
6% is about the best we can do with a closed cycle. Extra-terrestrial sources
could push those numbers even lower by running up to a pure D-He3 reaction.

~~~
DennisP
Yep. I think 6% is pretty good...it's enough so you don't need a heat cycle to
extract electricity, and dealing with the neutron damage is easier than going
to Uranus. But working fusion reactors probably also means working fusion
rockets, and if we find ourselves going to Uranus anyway, all the better.

If we get _really_ good at fusion we could also use boron fusion. It uses the
most common isotope of boron, which is plentiful on Earth, plus regular
hydrogen, and the main reaction is aneutronic. There'd be some minor side
reactions but it'd be under 1% of energy as neutron radiation, probably better
than you'd get with deuterium in the mix.

------
mrfusion
It's weird to consider "parasitic" loss a problem. You just factor that into
the total output. If it's high enough you're good.

~~~
nkoren
Absolutely. Net output per $ of opex (+ amortization of capex, decommission
costs, etc.) is the only relevant metric. Parasitic power loss is
categorically not an issue.

This is a mistake that engineers frequently make when they are too narrowly
focused. You see it all the time in rocket engineering. The rocket equation
dictates that performance drops off rapidly as the mass of the vehicle becomes
heavier, or the efficiency of the engines worsens. So rocket engineers are
obsessed with saving weight and increasing engine performance.

However: _performance_ , in absolute terms, doesn't actually matter. What
matters is that you get your stuff in orbit, whether that's done efficiently
or not.

Up to a point, you of course _do_ need to worry about vehicle weight and
engine performance -- with too much of the former or too little of the latter,
you won't be able to launch _any_ payload. This is analogous to the "break-
even point" for fusion power.

Beyond that point, however, there's a tradeoff to make: if you need to launch
a larger payload, you can either improve the weight or the engines -- or you
can just throw more propellant at the problem.

Many engineers scoff at the latter approach, because it is utterly inelegant
(and doesn't require as many engineers to accomplish). But rocket propellant
is cheap. Really cheap. A cost-driven analysis that compares improving
efficiency vs. throwing more propellant at the problem will often favour the
latter.

The reason SpaceX succeeded in reducing launch costs -- where NASA's engineers
failed to do so for 50 years -- is because they were willing to do this
analysis and go to market with a lower-performance rocket. They preferred to
spend an extra $100k on kerosene than an extra $10M milling engine parts out
of unobtainium. Having done so, they then iteratively figured out how to make
a cheap rocket high-performance -- their rockets are now _very_ high-
performance -- which turns out to be much easier than figuring out how to make
a high-performance rocket cheap.

Anyhow, this article gives me a strong whiff of that kind of engineer's bias,
where the good is the enemy of the perfect.

[Edit: typos.]

~~~
ckozlowski
I'm not entirely sure that what you listed is the reason SpaceX has been
making such progress; NASA seems perfectly willing and capable of making
cutting edge engines (or rather, their contractors do). Whether or not their
organization has the risk-taking and agility to change approaches like SpaceX
does, that's another matter.

However, I don't think in rocketry that "throwing propellant at the problem"
is ever a solution, as propellant has weight. Efficiency is indeed incredibly
important, because adding more fuel means having to lift more weight, which
means you need a bigger engine, which needs more fuel to run, etc in a vicious
cycle. One of the solutions of course, is to burn more of it at once (ie.
multiple engines), but there's limits to what's feasible. (speed/atmospheric
considerations.) In other words, it's not a linear matter of throwing more
propellant. Costs can go up, quick.

Coming around to the issue at hand, I can absolutely see having a high minimum
threshold for a fusion power plant, where the plant needs to be large enough
to generate a sizable return (excess power) for it's initial outlay, but also
be able to make the maximum return (high consumption) of that power generated.
You can build a massive plant in the midwest, but if the demands on it are
quite low, then the economics of it doesn't work out.

That means that the economically feasible scenarios for a fusion plant at this
time are probably quite limited. I'm sure that will improve greatly over time.
But it seems to be that the author's point is that right now, even assuming
the technological issues are solved, it is probably isn't as cost-effective as
some make it out to be.

------
MR4D
There are many good points here, but I'm dismayed at the complete lack of
discussion (heck, no mention even!) of stellarators. It seems to me that
computing power has made them quite viable (as shown by the German Wendelstein
Stellarator), while the Tokamak design is basically an extremely old Russian
design that has never performed to expectations.

So if I were stuck with his assumption that fusion = tokamak, then yes, he'd
be completely right. But if stellarators achieve their promises, then he's
missing the answer completely (and given the Germans success with the
Wendelstein, I have a strong confidence that tokamaks will be shuttered within
a decade; abandoned to the better technology of the stellarator).

------
cfv
This is one article that can be greatly improved by adding "fucking" before
every instance of "sun". I would also appreciate a number of citations, since
it's hard for me to take things at face value after this modern fake news
panic thing

~~~
Nadya
_> since it's hard for me to take things at face value after this modern fake
news panic thing_

A part of me is glad to see more people becoming increasingly skeptical. A
part of me is sad to see that people think that the problem is only a _modern_
one.

------
SubiculumCode
I predict that SpaceX and SolarCity will eventually roll out vast solar cell
arrays in space, because the sun puts out an unthinkable amount of energy that
misses earth entirely. ie The sun is already a spectacular fusion reactor. Use
it.

------
ChuckMcM
This is an interesting article from Dr. Jassby who has both patents and papers
on Fusion going back to 1977 at least.

And there are at least two things that stand out for me, the first is that he
goes out of his way to craft a narrative that is negative, and the second he
doesn't mention the half dozen or so fusion efforts that are on going beside
the NIF and ITER projects.

The interesting thing about the narrative is that it takes 'positive' things
and puts them in a negative context. For example it takes power to run a
fusion reactor, and while the reactor can generate that power it lowers the
net output. At the same time, if there is a problem and the reactor turns off,
and there is no 'cool down' problem like there is in a fission reactor. No
steaming pile of intermediate fission products decaying to generate way too
much heat long after you turned the off switch to off. You can portray that as
"gee it has to waste a huge chunk of energy just keeping itself running." but
that seems trivial given that things like cars have the same issue. Part of
the engine power goes into run the fuel pump, or the alternator.

This sort of thing recurs in the article and is perhaps most egregious in
characterizing the neutron flux as a proliferation hazard. While it is
absolutely true you could design a fusion reactor whose purpose was to create
fissile material for bombs, that design would look nothing like a power
reactor, nor could you easily (maybe even possibly), actually 'convert' a
design that had been built and deployed to generate power into one that could
create fissile material. So what is the goal of combining the 'facts' that
high neutron fluxes of low energy neutrons can weaponize U238, and that fusion
power generation can generate high neutron fluxes, without also explaining
that a fusion reactor designed to make power couldn't possibly be co-opted to
make bombs? Why leave the inconvenient fact off unless you're attempting to
mislead the reader? And what is the point of misleading them?

And that really makes me wonder, what exactly is Dr. Jassby trying to say
here? I could completely understand an article that says "Hey, while fusion
has some desirable properties, it is going to be expensive, and from where I
sit it is going to be more expensive than the power it generates is worth."
That is a perfectly reasonable discussion to have and one that should be had
with people looking at building fusion devices.

It also makes me wonder why he doesn't mention some of the other groups who
are designing and building much simpler and perhaps more efficient systems (in
terms of net energy production). Does he not keep up with the field or does he
omit them because they don't add to the generally negative tone? All in all
this article left me with more questions than insights.

~~~
abalone
_> While it is absolutely true you could design a fusion reactor whose purpose
was to create fissile material for bombs, that design would look nothing like
a power reactor_

This directly contradicts the article:

"The open or clandestine production of plutonium 239 is possible in a fusion
reactor simply by placing natural or depleted uranium oxide at any location
where neutrons of any energy are flying about. The ocean of slowing-down
neutrons that results from scattering of the streaming fusion neutrons on the
reaction vessel permeates every nook and cranny of the reactor interior,
including appendages to the reaction vessel."

~~~
ChuckMcM
I challenge you to find anywhere in the ITER facility or NIF facility where
you can insert, leave, or remove any amount of natural or depleted uranium
oxide at all, much less where it could be exposed to neutron flux. There is a
wealth of information on the iter site you can read to understand just how
difficult it would be.

------
sundvor
I thought I'd link in DotNetRock's recent geek out session on fusion power -
others might like it, very much on topic:

[https://player.fm/series/dot-net-rocks/fusion-power-
update-g...](https://player.fm/series/dot-net-rocks/fusion-power-update-geek-
out)

------
madaxe_again
"In experiments to date the energy input required to produce the temperatures
and pressures that enable significant fusion reactions in hydrogen isotopes
has far exceeded the fusion energy generated."

Wrong. NIF and others have achieved Q>1, albeit in single events.

[http://www.bbc.co.uk/news/science-
environment-24429621](http://www.bbc.co.uk/news/science-environment-24429621)

~~~
leephillips
No, they haven't, not even in single events, although their press releases
claim that they have. Their actual papers make it clear that the claim of >1
energy gain is a result of somewhat arbitrary definitions. There has not been
a single shot on the NIF where more energy was supplied by the fusion reaction
than was used to fire the lasers - it's not even close.

~~~
SomeStupidPoint
Are you guys talking about different things?

One seems to be talking about energy released by while the other is talking
about energy captured from.

I think GP was criticizing the news for making it sound like the first hasn't
happened when only the second hasn't happened. (At least, in my
understanding.)

~~~
Spare_account
The BBC article linked above describes a very specific scenario which matches
neither of your described options.

" _The amount of energy released through the fusion reaction exceeded the
amount of energy being absorbed by the fuel_ "

This doesn't describe the relationship between the amount of energy injected
by the lasers and the energy emitted by the fusion reaction. Presumably a lot
of the energy injected by the lasers is wasted, some of it is absorbed by the
fuel and it is this absorbed amount that was exceeded by the energy released.

There is even a clearer statement in the article:

" _This is a step short of the lab 's stated goal of "ignition", where nuclear
fusion generates as much energy as the lasers supply._"

It seems to me that the following order of energy levels exists with present
technology:

Energy supplied to Lasers > Energy injected into system by lasers > Energy
absorbed by fuel > Energy released by fuel > Energy captured to generate
electricity from

~~~
leephillips
'This is a step short of the lab's stated goal of "ignition", where nuclear
fusion generates as much energy as the lasers supply.'

Which is just what I was pointing out. And it's a large step from honest
break-even, where you count the energy input into the laser system (it's not
100% efficient). And a huge step from practical break-even, where you count
the energy required to run the plant.

~~~
Spare_account
I was attempting to build on your contributions, but I decided to do it the
same level as your comment because it made more sense to address
SomeStupidPoint directly.

Attempt at constructive criticism: I think your answers were a little _too_
concise for some members of this audience and I decided to help out by
expanding on your points a little.

I've factored your comment about input energy into the lasers in my reply
above.

~~~
leephillips
Thanks. I was probably too concise, but only had a couple of minutes.

------
cletus
I've been hearing about and hoping for fusion power since probably the 1980s.
The more I think about it the more I think it's probably a pipe dream.

The idea appears so simple an elusive: combine Hydrogen into Helium (and there
are variations that use Helium, particularly He-3 as a fuel), which releases
energy. Hydrogen is essentially limitless (He, particularly He-3, less so).
Stars do it all the time.

The two big problems are of course:

1\. Containment. How do you contain something that's heated up to millions of
degrees? Magnetic containment has been the obvious candidate since hydrogen
heated sufficiently loses it's electrons and becomes a H+ ion but this so far
seems far easier said than done; and

2\. Neutrons. Fusion using deuterium, tritium, He-4 and He-3 releases varying
amounts of neutrons. These can't be magnetically contained (obviously) and
they're destructive. We can achieve fusion but neutrons end up pretty quickly
destroying the containment vessel.

Stars solve the first problem quite easily: with gravity. This isn't something
that's useful to us. A star exists in a state of a balance of two opposing
forces: gravity from the sheer their sheer mass trying to crush them vs the
outward pressure of the fusion processes they're undergoing.

The differences in potential size are massive. A star like our own sun will
eventually become a red giant extending about to the orbit of the earth.
That's 150 _million_ km. Likewise a star larger than ours can end up
compressed to something 10 miles or less across. This just illustrates the
differentials in forces involved.

At this point I'm honestly not convinced that this is an economically solvable
problem. It's not sufficient to output more energy than you input either.

Let's say a fusion reactor costs $1B to produce, has maintenance costs of
$20m/year and has a life of 50 years. That's (at least) $2B you need to
recover in capital costs from your "free" energy.

I honestly think burning a fuel of some sort will be here for a long, long
time. I don't want to discount the rising importance of wind and solar. I do
believe that with the ever decreasing costs these will become even more
important, even critical, in the future. They simply won't completely replace
some kind of combusted fuel.

Now what that fuel economy looks like is an unknown. There is a course a limit
in what we can dig up out of the ground and to continue using it or something
akin to it we need to solve the carbon problem. So what we really need is:

1\. Some method of sequestering atmospheric carbon at scale; and

2\. Some method of storing excess renewable energy.

There are multiple solutions to (2), the most common of which today seems to
be using batteries. Current battery technology has come a long way but it has
a lot of disadvantages, not the least of which is its current reliance on
something that itself is limited (lithium). Plus obtaining all the materials
for batteries seems to be highly environmentally destructive.

It's unclear to me that without some major innovation batteries will only ever
be a niche technology for the likes of a few Teslas and airplanes. Now I'm not
saying that innovation won't happen. I'm simply saying current battery tech
isn't there yet.

Another potential solution for (2) is to use energy to construct a fuel that
can be transported and combusted eg [1].

Synthetic hydrocarbons have a lot of advantages. Convenience, relatively
simple tech and high energy density (important for weight). Large scale carbon
sequestration remains a huge sticking point however. Plus actual fossil fuels
remain cheaper than synthetics but this will eventually change either because
fossil fuels become much rarer or renewable energy costs get sufficiently low.

[1]: [https://www.quora.com/How-do-I-get-gasoline-from-wind-
power](https://www.quora.com/How-do-I-get-gasoline-from-wind-power)

~~~
FridgeSeal
One of the reasons it's still failed to eventuate is that the engineering and
scientific challenges are significant and funding for fusion endeavours is
already quite limited and has been declining. The benefits from fusion are
insanely good (I have read that in an energy-producing reactor, you would only
need ~250kg of deuterium to power the US for a year), so it would be foolish
to relegate it to 'pipe dream' status just because of the current
difficulties. It just needs continued effort and investment.

The 2 main issues are addressed in another couple of comments [0], [1]

Burning fuel is easy, of course it's going to stick around, but for maximum
efficiency and power generation capabilities, you can't really go past fusion.

[0]:
[https://news.ycombinator.com/item?id=14205346](https://news.ycombinator.com/item?id=14205346)
[1]:
[https://news.ycombinator.com/item?id=14203704](https://news.ycombinator.com/item?id=14203704)

> At this point I'm honestly not convinced that this is an economically
> solvable problem.

The energy industry as it is, is belligerent and seemingly resistant to new
technologies that aren't fossil fuel based. How long would this remain the
case if actual concerted (gov, scientific and industrial) effort was dedicated
to fusion rather than pissing it up the wall trying to hold on to fossil fuel
based approaches for mass scale power generation.

> It's not sufficient to output more energy than you input either.

The science says otherwise, if this was the case we wouldn't even be bothering
to get power out of it.

------
rplst8
What a Negative Nancy.

------
throwanem
Dog bites man, film at eleven.

------
VikingCoder
So who's going to figure out if this was sponsored by West Virginia Coal
Miners Union, Exxon, and Dr. Evil?

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adrianN
Releasing Tritium is no problem, even if it's in kilogram amounts, because, as
the author himself notes, the half life is less than two weeks.

Edit: My reading comprehension is clearly lacking...

~~~
leephillips
Where does the author note that?

"Tritium has a half life of 12.3 years which means it will be dangerous for at
least 120 years, since the hazardous life for a radionuclide is ten to twenty
times longer than its half-life"¹

If you come in contact with it during that time you will get cancer.

[1][https://www.nirs.org/wp-
content/uploads/factsheets/tritiumba...](https://www.nirs.org/wp-
content/uploads/factsheets/tritiumbasicinfo.pdf)

~~~
jerf
If tritium is released in its atomic form, it is only a hyper-local threat,
both geographically and temporally. I wasn't able to confirm this with a quick
Google, but I imagine tritium will just want to go up, up, up as fast as it
can, where it will never bother anybody again. (It's heavier than hydrogen but
still lighter per-atom than helium, which has the same behavior). It doesn't
have the problem fission fuels have where they like to seep into ground water,
and be both heavy metals _and_ radioactive.

Plus, there won't necessarily be a lot of it in a plant. Even if you're
accustomed to the surprisingly large energy density of fission fuels, you're
still not used to the even _larger_ power density of fusion fuels. We're not
talking moving tritium around by the tons... we're talking by the kilogram, or
tens of kilograms. Compared to the difficulty of building the fusion plant in
the first place, handling a few pounds of tritium safely isn't challenging at
all.

~~~
Zarathust
Tritium binds with oxygen and forms tritiated water. It then contaminates the
food chain and cause cancer. This is a current concern for populations living
around nuclear power plants.

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

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dsr_
When a reporter calls their credibility into question in the second sentence,
there's a problem.

"they would produce vast amounts of energy with little radioactive waste,
forming little or no plutonium byproducts that could be used for nuclear
weapons."

Fusion products are helium, neutrons, and neutrinos. Stars eventually fuse
products up to iron.

To generate plutonium requires a supernova...

~~~
hencq
The 'reporter' "was a principal research physicist at the Princeton Plasma
Physics Lab until 1999. For 25 years he worked in areas of plasma physics and
neutron production related to fusion energy research and development. He holds
a PhD in astrophysical sciences from Princeton University."

Do you think it's perhaps possible that the author knows what he's talking
about? If you'd continued reading after that second sentence you might have
come across:

> In fact, these neutron streams lead directly to four regrettable problems
> with nuclear energy: radiation damage to structures; radioactive waste; the
> need for biological shielding; and the potential for the production of
> weapons-grade plutonium 239—thus adding to the threat of nuclear weapons
> proliferation, not lessening it, as fusion proponents would have it.

~~~
c517402
I don't understand why the OP considers sneaky Pu239 production a
proliferation problem, but doesn't consider unaccounted for tritium in the
fuel cycle and the general availability of Li6 to bread more tritium a
proliferation problem. Anyone?

~~~
philipkglass
Tritium is useful only if you can manufacture a fission weapon in the first
place. The vast majority of anti-proliferation efforts are aimed at preventing
fission weapons capability. Preventing a nuclear weapons state from graduating
from fission weapons to boosted-fission or full two stage thermonuclear is a
much lower priority.

