> “It would be an absurdity to use dirty fission reactors to fuel ‘clean’ fusion reactors,”
This seems like a non-sequitur. If we need to keep around (or even build) a few heavy-water fission plants to enable the fusion industry, what's the problem? The simple phrasing of fission as "dirty" really shows the quotee's biases. You could easily envision a stable energy mix with a few percent of fission, the rest fusion and storage/peaking power, and that would be far, far cleaner than our current GHG/pollutant-heavy mix of fossil fuels.
It seems quite premature to call this a "crisis" since we already have proven ways of manufacturing the required ingredient. I suppose the risk is just that this pushes up the price of fusion in the initial phases of deployment, providing an "activation cost" that delays fusion from taking over, but that's quite a speculative concern at this point.
It's actually tilted very far in the opposite direction. The ratio is something like 600:1 heavy-water fission to fusion. A mix of 99.8% fission and 0.2% fusion, if your fusion is relying on that as its sole source of tritium.
- "Small quantities of tritium are also produced by CANDU-type nuclear reactors—on the order of 100 grams per year for a 600 MW reactor,"
No tritium producing facility separates out nearly all tritium. Tritium separation and handling systems are expensive and demand has been low. It is not that more reactors are needed to meet demand. If demand ramps then the untapped supply can simply be tapped.
Fair enough, perhaps I was oversimplifying with my example. It seems from the OP the plan is to transition to breeding the tritium in fusion reactors, and that we currently have enough fission-produced tritium to plausibly bridge to those fusion-based processes. And the concern is that the fission reactors might shut down before we bootstrap the fusion reactors.
Still, as I said originally, it sounds like keeping our current level of fission reactors around should solve the bootstrapping problem.
> The simple phrasing of fission as "dirty" really shows the quotee's biases.
And I think their failure to really understand fusion power either. The sort of fusion reactors we build first will produce tons of neutron radiation, which over time will turn the whole reactor itself into radioactive nuclear waste.
Being triggered by the use of the word "dirty" for fission reactors, in comparison with fusion reactors no less, is far more telling than the use of the word. It creates radioactive waste. Creating waste is dirty. The promise of fusion is not to do this. Requiring the former for the latter is a strange proposition when viewed threw the only lense that makes sense for fusion power: cleanliness, the absence of dirtiness.
The love for nuclear power some internet communities exhibit has far left the realm of the science people often invoke as their reason and gone into full-on scientism. Nuclear scientists have respect for radiation. They wouldn't take offense with the mere mention that it has unwanted byproducts. They built and ran a couple hundred reactors for a few decades, and only two of them managed to render large swaths of the landscape into uninhabitable wastelands, which is quite a feat. But it was only possible because they didn't minimize the danger with the sort of I-would-love-a-reactor-in-my-backyard attitude that seems to be prevalent now. Which is, by the way, not only getting the science wrong, but also the politics: nuclear power is out not because it is dangerous, but because it is too expensive and, at this point, too slow to build.
While science bros have been huffing isotopes, actual scientists, with the help of some eerily effective subsidies, have improved solar and wind power and battery technology to the point where it is competitive and scalable not just to replace nuclear power, but even coal. Why people keep making the same arguments as they did a decade ago, a time span in which those technologies became 80-90% cheaper and more efficient, cannot be explained by the natural sciences.
Solar energy production is not 100% clean. It never will be regardless if coal is used or not. That doesn't mean it's bad. The goal isn't purely clean energy. The goal is improved sources of energy.
Hopefully coal isn't used in the future. But things don't appear to be on track.
Unfortunately, because black and white thinking and evaluating energy sources without comparing them has resulted in a shortage of natural gas (thanks to fossil fuel divestment and ESG) and energy producers falling back to coal. The worst possible source of energy.
If anyone was wondering if SPARC and ARC care about this, SPARC onsite tritium inventory is planned to be fairly low: just 10 grams (not kg) in this 2018 SPARC paper[0]. I would also speculate that 200 kg/year sounds a little bit too high, although I can't find an ARC paper to corroborate (the magic words you want are "total on-site tritium inventory").
ITAR should be shut down. Straight up. It's a complete waste of taxpayer funds taht holds no prospect of producing commercially viable power. Its design constraints were decided decades ago. Since then science and engineering has advanced a lot.
I'd love if it fusion became commercially viable but I'm doubtful it ever will. At the least the kind involving fusion atoms in a plasma for all the documented reasons, most notably plasma turbulence and the power loss and container damage from neutron escapes.
I'm not that concerned about a shortage of tritium. That's a solvable problem. In fact we probably need a variety of breeder reactors for things like this and producing plutonium for deep space probes anyway.
Fusion is a trap for many because it seems so easy. I mean the Sun is doing a lot of it. But the Sun is relatively inefficient (which is compensated for by mass) and it solves the containment problem with gravity.
I'm not sure about the scale here, but is it really as crazy as the article says to use tritium that is formed from fission? What's the ratio of fusion:fission energy you'd need? I can't imagine even if it was 50% or 25% that it wouldn't be worth doing seeing as you'd just be fuelling a clean energy source from the waste stream of another energy source that doesn't produce CO2.
The reaction is supposed to be self-sustaining. The reactor walls are supposed to emit more than enough tritium to satisfy your needs.
Whatever you bring from outside is just to bootstrap it once you turn it on. (I imagine they are not collecting the tritium between runs, but it's something you are expected to do.)
Wait, so then at _whatever_ cost, the cost of producing Tritium is sorta moot, right? Whether it's building reactors or investing a tonne of energy, the cost of creating the amount of tritium needed is met with theoretically infinite profits?
Yes, in theory. On practice the problem is that the ITER doesn't recover enough tritium for economical reasons, and thus needs a constant supply of it for running its experiments.
There is another, unrelated issue that if we decide to scale (H + D) fusion power, for decades we will need more tritium than they can generate.
There will never be any marketable fusion power at all, never mind "infinite". Power from Tokamaks necessarily costs at least 10x power from fission, and fission is already not competitive, and gets less so each year.
All. Even nominally commercial ones get a whopping disaster liability subsidy, and decommissioning cost is omitted from the price, but charged to ratepayers on top of whatever actual power they are also paying for.
It will cost at least a $billion to take apart and dispose of Indian Point, shut down recently because it was leaking radioactive stuff into the Hudson.
See, now I know you're just lying because the equation isn't at all the same across all countries. Maybe you don't like nuclear and that's fine but you don't have to lie about it.
It remains the case that NPPs have never, anywhere, been built into a competitive market. They are only built when customers can be forced to pay for them.
So, what's your argument? That people won't buy nuclear energy on an open market or that an open market for nuclear energy doesn't exist?
In Sweden, where I live, about half of our electricity is from nuclear. It's built and operated by a state owned entity called Vattenfall and while they currently have a politically appointed board that is against nuclear they operate (for profit) all of our nuclear reactors. The only reason we don't build more is because they've made it practically impossible (not illegal) to expand nuclear energy through various political motivated decisions. Sweden had a referendum on the continuation of nuclear energy after the Chernobyl accident, we did vote, though by a narrow margin to transition away from nuclear. However, this past winter we had huge supply issues and people ended up having to pay 4x for electricity due to the premature shutdown of nuclear (meanwhile we had to power up oil and gas burning to compensate). Right now, most people in Sweden are of the opinion that we should keep our nuclear reactors. I, together with several others would like to us to expand our energy production from nuclear to prevent a reliance on oil and gas.
Politics is how policy is determined. People have tried other ways. Sometimes they worked. For a while.
Diverting money from building out renewables (and transmission lines) to build nukes ensures, at minimum, another decade of increasing reliance on oil and gas, and then paying more for power than you would have for renewables.
Politics aimed at making a specific type of energy unprofitable by taxing it to death is not. It's activism.
Sweden cannot depend on solar alone, we have plenty of hydro in the northern parts of the country and wind doesn't work during winter. Wind also kills birds and insects, en masse.
People have an irrational fear towards nuclear. Fact is, very few people have died because of nuclear energy. If you compare deaths vs produced watts, nuclear is the single safest energy source by several orders of magnitudes.
Also, I don't know if that's a typo or a misunderstanding but we are not talking about nuclear weapons, i.e. nukes we are talking about thermonuclear energy production. These are two different things altogether.
The kinds of fusion generators that are considered for the near future produce most of their energy as kinetic energy of neutrons.
The energy of the neutrons is transformed into heat by adsorbing them into some shielding walls. The materials for those walls will be chosen to minimize the quantity of radioactive waste that is produced by the extremely intense neutron irradiation, but it is impossible to avoid completely the production of radioactive waste.
So all the fusion generators planned for the near future will generate radioactive waste, but in significantly less quantities than fission reactors of the same power.
Because they produce an intense neutron flux, like the fission reactors, the fusion reactors can also be used for element transmutation by neutron capture, e.g. for producing tritium or for producing lightly-doped silicon crystals for the high-voltage electronic devices (by transmuting silicon into phosphorus).
However, such transmutation applications usually also need the use of a neutron moderator, to slow the neutrons down to whatever speed is optimal for producing the desired isotope, e.g. tritium. For tritium, heavy water can play both roles, of the neutron moderator and of the target containing the element to be transmuted.
You could absorb neutron flux in a thousand tons of molten 6Li/7Li, and then try to separate grams of tritium from that thousand tons of molten, extremely inflammable metal, on a continuous basis. Good luck with that.
Renewables do not incur such operating expenses. Put renewables and a fusion reactor on the grid, and fusion would never, ever win a bid.
"Fusion .. will generate ... less ... than fission"? The whole damn ten-thousand-ton reactor becomes radioactive waste in short order. Fortunately, none will be built, so it is only a theoretical problem.
Hydrogen does not seem to dissolve very well in molten lithium. It is quite easy to separate on the lab, but yeah, the practical consequences of convection currents and putting it through a heat exchanger may change this.
Anyway, I imagine the people studying fusion have an answer to this, since it only requires normal centuries-old chemical knowledge.
I also do not believe fusion will ever be a competitive power source for stationary applications on Earth.
Despite their fabled immiscibility, a few grams of oil would dissolve very thoroughly in a thousand tons of superheated water. The numbers matter.
The people studying fusion are carefully restricting their attention to the immediate problems of getting it to work at all. E.g., ITER will have no lithium blanket.
They figure on building another whole reactor to be completed (initially guessed) 15 years later at (initially guessed) 4x cost to begin tackling practical difficulties of extracting useful thermal energy.
I dug more about this because it's an interesting topic. Basically we don't know how long a fusion generator will last before radioactivity forces its decommissioning because none exist yet, but fortunately it's short-life isotopes, about 50-120 years before they become safe. Orders of magnitude better than fission waste.
I don't know about fusion vs renewables, because renewables are better, but they need a lot of non-renewables to be manufactured. If a fusion reactor lasted 100 years, it would be a much better option than renewables.
The reactor would need to be replaced frequently as the chamber walls and molten-lithium pipes weaken from neutron bombardment, every two years, maybe as long as five. By the time they could build one, there might be some way to make it last ten?
It needs even bigger containment than a regular nuke because reactive molten lithium bursts into flame on contact with air. The oxidized product is an exploding cloud of vaporized radioactive drain cleaner. A thousand tons of lithium make a lot of drain cleaner.
And again, by that time all our power will be cheaply supplied by renewables with no disastrous failure modes, and maintained just by taking bits down and putting up new bits, in shirtsleeves when weather favors it.
> Basically we don't know how long a fusion generator will last before radioactivity forces its decommissioning
That was one of the main questions the ITER was supposed to answer, wasn't it? AFAIK earlier designs were quite short-lived, but some small changes fixed it. We will know how long they last as soon as we don't have an ITER anymore.
It is scheduled to be done in 2035, which means in practice for projects like this 2040 or 2045, and at $25B meaning $30B+. It will surely be abandoned before then, and we still won't know.
What were these small changes that fixed it? Did they have anything to do with the cost going up by 3x?
Anyway, inducing radioactivity is not what would use it up. That just makes it super-expensive to do repairs. It would get used up through neutron bombardment weakening the crystal structure of the metals it is constructed of.
No, it wasn't. ITER uses materials (like CuCrZr) that are unsuitable for a production reactor, ITER will not perform tritium breeding (except in a few experimental modules that won't be sufficient to prove that technology), and ITER will only operate at full power on DT for at most a few weeks total over its lifespan.
Not really an issue though, as tritium has a half life of 12 years, and the amounts produced would be negligible anyway. You could probably release it into the atmosphere harmlessly (not that regulations would ever allow that, though).
In my sibling comment, I calculate 600:1 fission:fusion, for the heavy water reactors they're talking about.
(I think it could be somewhat better if it were a fission reactor optimized for tritium, but I don't know the numbers for that. I think that would entail fast-neutron reactors with enriched ⁶Li blankets -- analagous to what the fusion reactors are planning to do).
>in, … 12.3 years…, half of the tritium available today will have decayed into helium-3.
When I saw this, I thought that sounded odd, shouldn’t the atomic number go down with radioactive decay? but it turns out that in this case what happens is one of the neutrons splits into a proton, an electron and an electron neutrino so the atomic number goes up by one (unlike the more familiar fission reactions of the heavier elements where the atomic number decreases). So much physics I’ve either forgotten or never learned.
This is the standard beta radioactive decay, which increases Z by 1, while the alpha radioactive decay decreases Z by 2 (and gamma decay does not change Z).
For every A (the number of nucleons in a nucleus) there is a ratio between (A-Z) and Z (i.e. between the number of neutrons and the number of protons) for which the mass of the nucleus is minimum.
Any other isobaric nuclei have an excess of mass over the nucleus with the optimal neutron/proton ratio, so they will decay towards it. The nuclei with too many protons will capture electrons or emit positrons, while the nuclei with too many neutrons will emit electrons, increasing the number of protons with each emitted electron, until the optimal neutron/proton ratio.
For the decay products of uranium and thorium, there are always too many neutrons, so the normal beta decay is what always happens.
It is possible to artificially produce nuclei with too many protons, and there are a few such unstable isotopes that are produced naturally, which decay by the reverse beta decay (electron capture or positron emission), where Z decreases by 1 for every captured electron / emitted positron.
For A = 3, the nucleus with minimal mass is helium-3. Tritium has too many neutrons in comparison with helium-3, and it must get rid of them by emitting an electron.
> "Right now, the tritium used in fusion experiments like ITER, and the smaller JET tokamak in the UK, comes from a very specific type of nuclear fission reactor called a heavy-water moderated reactor."
You litterally just need to make more of these heavy-water moderated reactors, which are rare and approaching end of life, but certainly you can build more of them if it was the difference between having endless energy or not.
One of the main objectives of ITER is to test Tritium Breeding technologies for DEMO. There is no shortage due to heavy water plants shutting down because it was never planes to use Tritium from that source in the first place!
ITER will not produce significant tritium, since most of its walls are not covered with breeding blankets. Most of the neutrons it produces from DT fusion will not hit a blanket module and therefore not breed tritium.
* In a perfect world, there would be a more ambitious program developing the breeding technology in parallel to ITER, Willms says, so that by the time ITER has perfected the fusion reactor there’s still a fuel source to run it
* Like many of the most prominent experimental nuclear fusion reactors, ITER relies on a steady supply of both deuterium and tritium for its experiments
* When it’s finally fully switched on in 2035, the International Thermonuclear Experimental Reactor will be the largest device of its kind ever built, and the flag-bearer for nuclear fusion
* And as ITER drags on, years behind schedule and billions over budget, our best sources of tritium to fuel it and other experimental fusion reactors are slowly disappearing
* Right now, the tritium used in fusion experiments like ITER, and the smaller JET tokamak in the UK, comes from a very specific type of nuclear fission reactor called a heavy-water moderated reactor
* “We’re hitting the peak of this tritium window roughly now.” Scientists have known about this potential stumbling block for decades, and they developed a neat way around it: a plan to use nuclear fusion reactors to “breed” tritium, so that they end up replenishing their own fuel at the same time as they burn it
* “Calculations suggest that a suitably designed breeding blanket would be capable of providing enough tritium for the power plant to be self-sufficient in fuel, with a little extra to start up new power plants,” says Stuart White, a spokesperson for the UK Atomic Energy Authority, which hosts the JET fusion project
* “It would be an absurdity to use dirty fission reactors to fuel ‘clean’ fusion reactors,” says Ernesto Mazzucato, a retired physicist who has been an outspoken critic of ITER, and nuclear fusion more generally, despite spending much of his working life studying tokamaks
* “After 2035 we have to construct a new machine that will take another 20 or 30 years for testing a crucial task like how to produce the tritium, so how are we going to block and stop global warming with fusion reactors if we will not be ready until the end of this century?” says Mazzucato
Arthur Turrell's book, The Star Builders, is an excellent overview of the state of the art of nuclear fusion technology. Unfortunately, however, fusion is unlikely to be radically cheaper than other sources.
Okay I will not post these anymore. I might share the summarization algorithm I wrote that enables me to create these quickly, though. Thanks for helping me understand the ethos of curiosity and the diffs as the underlying principles.
The real question is whether it's more expensive than solar/wind plus the batteries required for dispatchable power.
The answer depends on the reactor design, which Elon doesn't know. There are a lot of possibilities, and if the first ones are too expensive, later ones might not be.
Yes, we discussed that pretty extensively the other week. It starts out with unrealistic assumptions for fission, including a 25-year lifespan (compared to the actual average age of US reactors of forty years) and twice the discount rate for fission as for everything else. Fix those things and nuclear does better.
It also uses US fission prices, which are higher than in most of the world. On top of that, the US has unusually good geography for both wind and solar. Nuclear is much more competitive in many other countries. One ironic example is Germany, where the model suggests a 100% nuclear grid even at US nuclear costs, as long as the lifespan and discount rate are corrected.
And as I told you last week, the numbers are actually optimistic compared to US (or actual EPR) numbers. In particular, it assumed the reactor cost 6000 euro per kW, which is considerably less than what EPR ended up costing.
And I linked you a paper surveying global nuclear costs, showing much lower costs in many areas and no overall trend of increasing costs. Here's the paper again:
Most of those points that were low were either France or Korea. France with EPR has lost whatever mojo they claim to have had (those earlier cost figures are not verifiable) and Korea turned out to achieve low costs by corruption and omitting safety features.
The lowest, sure, but those are around $2000/kW. The bulk of the points on the graph are still below $4000/kW. That includes Japan, India, and Canada, along with a lot of early US reactors.
Also, do you have a source for early French costs being unverifiable? I don't see where that's mentioned in the paper, so it doesn't seem right to just dismiss the data unless there's another source giving us good reason to do that.
As for the EPR, seems to me the conclusion there is just to not build any more EPRs.
In America the NRC issues a 40 year license to a reactor which then, after a review, can be extended. 40 years is the lifespan of the initial license not the plant.
Actually, when the Earth was formed, it contained a non-negligible quantity of plutonium (supernovae produce all the elements until Z=100, much over the Z=94 of plutonium, but the heavier elements had already decayed before the interstellar dust reached the nascent Solar System).
Because the longest-lived isotope of plutonium has a half-life close to 100 million years, so some 45 halvings have happened since the Earth formation, almost all primordial plutonium has decayed by now.
A few atoms of the primordial plutonium are still around us, though they are much too few to be easily detectable (there have been claims that some very sensitive experiments have detected them).
I thought the end game was aneutronic fusion using lithium and deuterium anyway creating only charged particles instead of high energy neutrons that are dangerous and damaging to the reactor. If nuclear fusion ever wants to be commercially viable, it must not depend on tritium.
Helion is working on a deuterium/helium-3 reactor, which if it works will produce only 6% of its energy as neutron radiation. YCombinator was an investor. They've run six reactors and are building a seventh now for a net power attempt in 2024.
There are also at least four companies working on proton-boron fusion, though all but one are very small. (TAE is the exception.)
D-3He. But 3He comes only from decaying tritium, so same problem.
At least D-3He might possibly be made to produce economically competitive power, if there were any 3He to burn in one. But it might be useful in space probes.
> Tritium breeding was originally going to be tested as part of ITER, but as costs ballooned from an initial $6 billion to more than $25 billion it was quietly dropped. Willms’ job at ITER is to manage smaller-scale tests. Instead of a full blanket of lithium surrounding the fusion reaction, ITER will use suitcase-sized samples of differently presented lithium inserted into “ports” around the tokamak: ceramic pebble beds, liquid lithium, lead lithium.
> Even Willms admits that this technology is a long way from being ready to use, however, and a full-scale test of tritium breeding will have to wait until the next generation of reactors, which some argue might be too late. “After 2035 we have to construct a new machine that will take another 20 or 30 years for testing a crucial task like how to produce the tritium, so how are we going to block and stop global warming with fusion reactors if we will not be ready until the end of this century?” says Mazzucato.
You can't respond to the bad guys with a plea for them to stop what they are doing because you would rather spend the money on something else.
That isn't to say that battles should not be picked carefully, just that sometimes you don't have a choice and have to deal with a situation and spend lots of $$$ and sometimes blood in order to avoid a worse situation. Even in the context of "last 2 months alone" it isn't clear what specific action is being referenced so the comment is just too abstract, IMHO.
In some cases it makes sense to engage, in others it doesn't. There is no single correct answer unless you want to enter into a discussion of pacifism.
That is not what that comment says. It clearly means money can be spent when we go to war, or when we need pandemic money, but a measly 25billion in comparison suddenly is “a lot”. If we want fusion, we have to invest.
We do have a choice about Ukraine, just as we had a choice about Syria, Libya, Iraq, Yemen, Afghanistan, Vietnam, Honduras, Guatemala, El Salvador, etc. We are making the wrong choice now, just as we made the wrong choices before. Although we kill lots of people, many of them innocent rather than "bad", we never actually "avoid" worse situations. In cases like Libya our intervention has worsened human life by every measure. In other cases we might have delayed inevitable events somewhat (e.g. Vietnam couldn't go to war with China until it finished beating us). The "specific action" in every case is spending public funds, which is the purpose of the USA military, intelligence services, diplomatic corps, and news media, and has been since the Korean War. Insofar as they affect security at all, our military efforts usually reduce it.
$25 billion is about 9 Virginia-class submarines. The US has already built 22 and plans to build 66. Granted, they're very nice and important submarines, but it still makes $25 billion seem like chump change by national project standards.
Then it's a good thing we're not focusing effort on long-term solutions. We're spending a lot more money on rolling out renewables than we are on fusion research. That doesn't mean we should cut out long-term solutions entirely.
If we want to fund more renewables than we are now, then the place to cut back is the many fossil fuel projects that we're still investing in. Until we've done that, I think any positive effort deserves applause instead of complaints about focus.
ITER is not necessarily the best approach to fusion, although it's the best funded.
In any case if we can't breed tritium than we either need to shoot for higher energy D-D fusion or some other reaction or fusion will never be cost-competitive.
I mean fusion capable of practical power generation.
D-T fusion is the easiest, and yet super hard. Tokamaks are the only design that we know how to build in order to meet the goal, with maybe stellerators in second position. Inertial fusion work for scientific and military experiments, but are far from being a usable power source. Things like fusors and its derivative are great hobby projects with a few limited practical applications, but we are not even sure if it is physically possible to produce more energy than we put in. As for LENR (aka. cold fusion) we are essentially at the "thought experiment" stage, when it is not a scam.
One other idea that may work with current tech is to dig a large cave, line it with really thick material and detonate hydrogen bombs inside it, extracting energy from the heat of the explosion. I don't think I need to tell you that even if we can do that (unsure), we certainly shouldn't (absolutely sure).
Or, take, advantage of that really big fusion reactor we already have and makes us go around in circles.
Most conservatively, there are tokamaks that use more modern superconductors, able to support much stronger magnetic fields. Tokamak output scales with the fourth power of the magnetic field, so that allows the same output as ITER from a much smaller, cheaper reactor. The MIT spinoff CFS is doing this, along with Tokamak Energy in the UK. CFS is shooting for a net power attempt in 2025.
There are also various alternative designs, like Zap Energy's z-pinch, General Fusion's magnetized target fusion, and Helion's field-reversed configuration. Helion is attempting hybrid D-D/D-He3 fusion, the other two are D-T.
All the DT approaches suffer from poor volumetric power density, for fundamental reasons independent of the details of magnetic fields or confinement schemes. For that reason I feel Helion's approach is the least dubious.
Ironically, this is perhaps the smallest problem facing practical civil fusion power.
Probably the biggest problem is wasting time and budget on such dead-end technology as Tokamak, which can never in anybody's wildest dream be competitive with renewables, even given abundant tritium. But the conceivably useful D-3He aneutronic fusion depends on a supply of 3He, which is uniquely a product of tritium decay, and thus also depends on a tritium supply.
Thus D-3He would not be useful for baseload civil power, either. But it could be the only useful power source for projects in the outer solar system, for which a much smaller amount of 3He would suffice. It is hard to imagine another power source adequate in the outer solar system (aside from pB11 fusion which would be super if it is actually possible at all).
(No, mining 3He from the moon would totally not work at all.)
The whole point is to reach a Deuterium or Hydrogen reactor with a light lithium ignition in a lot of cases which would be easier to fuel than Tritium due do problems extracting it.
Tell that to the Sun. We already have a fusion reactor sufficient to meet all of humanity's energy needs, it's a gravitationally contained fusion reactor with a projected lifetime of at least one billion years, so why not just rely on that? Seems to have done wonders for the biosphere for the last one billion years, hasn't it?
Moreover, if we would really ever become able to produce by nuclear fusion a quantity of energy comparable with the energy received from the Sun, then that would cause by itself a great climate warming, so nuclear fusion is not a solution against it.
If the quantity of energy produced by nuclear fusion would remain negligible in comparison with the solar energy, then there is no need for it.
While on Earth using the nuclear fusion makes little sense, mastering it could enable the exploration and even the colonization of the Solar System.
It seems like every fusion post is bound to have at least one commenter point out that the sun is a working fusion reactor, as if literally anyone in these threads will learn something from this observation.
Roughly $50 billion has been spent globally on fusion research since the 1950s with nothing material to show for the effort; at what point do you stop throwing good money after bad? This strikes me as the learning from these posts.
I think you make an excellent point that fusion research is underfunded. NASA budget since the 50s is ~$1,400 billion — almost 30x what’s been put into fusion research. We’re asking fusion research to produce “free, clean, and carbon-free base-load electricity forever.” Seems worth a NASA-level of investment to me.
You could use the same logic to claim perpetual motion machine research is underfunded. The likelihood of the research leading to a useful result has to enter into it somehow.
Saudi Arabia alone exported almost $100 billion in crude petroleum in 2020 [1]. That was significantly less than the previous year.
Given these scales I'm not really sure $50 billion is a lot of money for the entire world to spend on an energy R&D project. In fact, that number seems surprisingly low, do you have a source for it?
I'm sure it is difficult to decide that since, as pointed out, there is a working example staring at us every day. So it always feel just out of reach.
Intel has working products, customers, shareholders, and fundamentally, accountability for that research spend. Results driven research funding is not unreasonable, unless you want to classify this research in the same vein as particle accelerators and a curiosity with no expectation of success (which is fine; just don’t sell as an energy silver bullet where there’s no evidence it can be delivered on). Hope is not a strategy nor a cost justification.
Just because the semiconductor's productivity gains have been massive on a short term time horizon, does not mean that fusion research has been a waste, or that is not on track to "deliver". Fusion as a technology is a long term bet and requires much more capital expenditure, for little short term return, then even semi fabs (which are notorious capital sinks).
Your mention of cost justification is ignoring the bigger picture that our economic system is setup to benefit public companies like Intel, and not grand research endeavors.
As an exercise to the reader, imagine what organizations/companies would exist if the contemporary economic incentive structures were different.
There is in fact no "track" with commercially competitive fusion-generated power at the end of it, tritium or no tritium. It's great that plasma physicists are being employed and enabled to do research, but that could be done much more cheaply and effectively by not spending on ITER.
Fusion reactor research is kind of interesting, I suppose it's making alchemy real in a way. Stars make things like helium and lithium from raw protons and electons and neutrons, apparently. and if humans could master that we could basically solve a lot of matter limitatation problems by just making whatever elements we needed at whatever scale from nothing but hydrogen as the raw material (maybe some helium too). That's basically all sci-fi at present, but who knows.
As far as making fusion reactors to boil hot fluids to drive steam turbine-generators to power the electrical grid... doesn't seem too likely. High-efficiency monocrystalline Si PV panel fabs would be a better investment.
> There are other ways of creating tritium but these techniques are too expensive to be used for the quantities required, and they will likely remain the reserve of nuclear weapons programs
Too expensive for clean power, just right to threaten the world
Just a quick reminder, we already have practical fusion with tens of thousands of years of runway available to us today. We choose not to do it because it sounds dangerous and it’s not politically expedient.
For those unfamiliar, I am talking about Project PACER. The fusion reactor proposed by Teller after the creation of the thermonuclear weapon. It may sound fanciful but it’s based on a simple precept. We can already induce fusion reactions, albeit in an unstable and explosive fashion. What if we took that warhead, surrounded it with a giant underground chamber made out of steel several feet thick, and let it explode while molten fluoride captured the heat?
Their work conclusively shows that this can be done, and that molten fluoride salts could capture most of the neutrons to prevent embrittlement. A single such facility could power the entire country. Oh and it could be configured to create Tritium in the process.
The project was terminated because it was "bound to be controversial" and
would "arouse considerable negative responses."
The math is sound. The concepts are sound. We could solve the comparatively minor engineering challenges and build one today while waiting on the the breakthrough needed for controlled, continuous fusion.
It lacks the key advantage of fusion reactors over fission: not contaminating its working fluid with radioactive isotopes. For something like PACER, you have to extract the heat by running the hot fluoride through heat exchangers to run steam turbines. This is difficult and expensive to make safe. Like with conventional fission reactors, you have to be extremely sure your heat exchangers will last 50 years with zero leaks, because you can't touch them once the system has been running. And leaks are extremely dangerous. So every weld has to be triple-inspected and so on.
A second disadvantage is that the parts would undergo constant thermal cycling. Conventional reactors are run at a very steady output level to handle base load, because turning them up and down regularly would cause the moving parts to fatigue and crack over time.
The project was terminated because there were formidable technical issues, it wasn't economically profitable, and there was a real possibility of catastrophic failure that could not be mitigated.
> Dropping about two bombs a day would cause the system to reach thermal equilibrium, allowing the continual extraction of about 2 GW of electrical power.
So the idea is to drop 2 nuclear bombs per day to get about as much energy as one gets from a pair of nuclear fission reactors? I seriously doubt that's cost-competitive with fission power.
Competitive with intermittent sources backed by fossil fuels? No, but those emit carbon emissions. And we lack the ability to add significant amounts of energy storage, so wind and solar will never conceivably break free of it's dependence on fossil fuels during non- production.
It's the most competitive non-intermittent and geographically independent source of carbon-free energy. Because it's the only such source.
It's not competitive with a power source containing fossil fuels. And there's no feasible way to run a grid composed of wind and solar without fossil fuels. Ignoring the fact that wind and solar generation is really wind, solar, and fossil fuels, to offset the intermittency is naive.
In areas without hydroelectric and geothermal potential, nuclear is the most competitive carbon-free and non+intermittent option. Because it's the only option. That's why for all your insistence that nuclear is uncompetitive, it produces more electricity than wind and solar combined.i
Renewables plus local storage, transmission line, and/or ability to burn imported ammonia or hydrogen suffices, and at radically less cost, with no risk of rendering large areas uninhabitable.
Storage at anywhere near significant levels does not yet exist, and might not be achieved in the time necessary to curb the worst effects of climate change. Ammonia and hydrogen storage has been proposed, for decades, yet remains out of reach at the scales necessary to make renewables viable.
Wind and solar is really wind, solar, and fossil fuels. Assuming that we'll be able to replace the last item with energy storage is betting the future of our climate on an engineering breakthrough. No such gamble exists with nuclear, countries like France have successfully produced nearly all their electricity with nuclear power for decades.
They actually want to detonate a H-Bomb every 45 minutes, all day every day. 32 nuclear explosions every day.
One does have to appreciate how these guys took anti-proliferation concerns with the nuclear industry and said "fuck it, everyone knows we're only doing this to make bombs, so lets make a shit ton of bombs". No more concerns about terrorists getting their hands on some yellowcake and making a dirty bomb. Now they have a full up H-Bomb factory moving so much product that security can get complacent.
We’re facing a catastrophe. I and others have described elsewhere that the path we’re on is much, much worse than even the most dire of predictions the IPCC makes. https://news.ycombinator.com/item?id=30947756
Teller et al anticipated your objection. It’s why the reactor is supposed to dig into sold rock. If there’s a catastrophic failure then it’s yet another subsurface nuclear test. And the more advanced designs considered for Project Plowshare produce minimal residual radioactivity. All of the products dissipate within 6 months.
So, in the worst case scenario, the facility gets buried under tons of rocks, far away from any water. And the residual radioactive products rapidly decay into being harmless with 6 months. Any induced radioactivity from the neutrons produced during the explosion will follow a fairly predictable pattern as well.
This can be done.
In exchange we get a reactor that creates nearly limitless power for entire countries.
Or we could chose a number of WAY safer fission reactors for the same cost and same power output (Pick your favorite Gen IV reactor).
We also don't end up creating a literal nuclear weapons manufacturing plant in every nation that wants to use this (since the "fuel" for this reactor is constantly detonating nukes).
I'm fine with either to be frank. I like that Gen IV reactors should have much cheaper deployment strategies.
Anything is better than the "drop a nuke in the hole" plan. Both Gen III+ and Gen IV reactors can hit the market before all the red tape is cut for prototyping the hole bomb.
Worst case scenario is you blow the doors off of the facility and tons of superheated radioactive fluoride salts are blasted into the air, along with the vaporized particles of all of the workers and the fissile material in all of the bombs in the staging areas.
The same line of reasoning says that we should build conventional light- or heavy-water reactors. The risk is minimal. And they're (a) tested and (b) much cheaper than PACER.
The advantage of a PACER setup is that you get a lot more bang (heh) per kg of uranium than you do out of a fission reactor. But the cost of uranium is not currently a problem with our fission reactors. We do have a problem with radioactive waste, but even that is way more political than it is technical.
I wonder which two senators are going to be ok with detonating 32 bombs in their state every day? This isn't the 50s, NIMBYs know how to make your life a living hell when trying to do anything nuclear.
One problem it solves is making reactors that can't produce material for nuclear weapons. That's pretty important if we want to deploy reactors outside the few countries that already have them.
I live near Indian Point, recently shut down. They tried thorium back when it was new. It cost too much then. Nukes of any stripe are not competitive now, and get less so every year. Thorium cannot save them.
Solutions that rely on a steam turbine generally lose to those that do not. A need to fool with fuel and security cost even more. Account for the disaster insurance subsidy and decommissioning cost, and they come out a marked drag on society.
That is, if you manage to complete one before it gets cancelled because renewables are already doing the job more cheaply than it can. We do better not to spend the initial $billions on what will never produce any marketable power. No such money is ever returned.
A nuke that runs only at night costs almost twice as much per kWh.
It's possible the economics have changed since the 50s. The non-proliferation argument certainly has: in the US in the 50s, making plutonium was considered a useful feature of power reactors.
> We’re facing a catastrophe. I and others have described elsewhere that the path we’re on is much, much worse than even the most dire of predictions the IPCC makes.
There are a lot of processes we don't fully understand so your claim is hard to substantiate. Also, if that was the case then a lot of people would probably just accept their fate.
It would have meant the end of nuclear arms control and non-proliferation efforts, an already difficult process. So yeah, that tends to arouse considerable negative responses.
Isn't the problem that the fuse for a fusion bomb is a fission bomb, and a fission bomb very violently disperses lots of radioactive material? What am I not getting?
It’s a sealed chamber underground. And the amount of fallout can be controlled. Some fusion designs are “cleaner” than others w.r.t. fallout.
From the wiki,
> A typical design called for a 4 m thick steel alloy blast-chamber, 30 m (100 ft) in diameter and 100 m (300 ft) tall,[9] to be embedded in a cavity dug into bedrock in Nevada. Hundreds of 15 m (45 ft) long bolts were to be driven into the surrounding rock to support the cavity. The space between the blast-chamber and the rock cavity walls was to be filled with concrete; then the bolts were to be put under enormous tension to pre-stress the rock, concrete, and blast-chamber. The blast-chamber was then to be partially filled with molten fluoride salts to a depth of 30 m (100 ft), a "waterfall" would be initiated by pumping the salt to the top of the chamber and letting it fall to the bottom. While surrounded by this falling coolant, a 1-kiloton fission bomb would be detonated; this would be repeated every 45 minutes. The fluid would also absorb neutrons to avoid damage to the walls of the cavity.
You control the detonation with either an engineered or natural cavity filled with fluid. You can then use the fluid as a big thermal reservoir to run steam turbines. Per wikipedia:
>"Dropping about two bombs a day would cause the system to reach thermal equilibrium, allowing the continual extraction of about 2 GW of electrical power."
Now... the part you're not getting is that if you can do all that, you can almost certainly just use conventional fission power generation, which is what we really, REALLY need to be doing anyway.
Great information!
Project PACER was certainly an attempt to introduce fusion reactors with the technology we currently have Mastery of.
In the early 1970s, both LANL and LLNL National Labs had PACER fusion programs.
Dr. Ralph Moir was the project leader for this program at LLNL.
Inertial Confinement fusion is "controlled fusion" to the very same extent as Magnetic Confinement fusion (the same fuels and fusion reactions are used and the same nuclear waste [stable nonradioactive Helium] is produced.
> “It would be an absurdity to use dirty fission reactors to fuel ‘clean’ fusion reactors,”
This seems like a non-sequitur. If we need to keep around (or even build) a few heavy-water fission plants to enable the fusion industry, what's the problem? The simple phrasing of fission as "dirty" really shows the quotee's biases. You could easily envision a stable energy mix with a few percent of fission, the rest fusion and storage/peaking power, and that would be far, far cleaner than our current GHG/pollutant-heavy mix of fossil fuels.
It seems quite premature to call this a "crisis" since we already have proven ways of manufacturing the required ingredient. I suppose the risk is just that this pushes up the price of fusion in the initial phases of deployment, providing an "activation cost" that delays fusion from taking over, but that's quite a speculative concern at this point.
- "a few heavy-water fission plants"
It's actually tilted very far in the opposite direction. The ratio is something like 600:1 heavy-water fission to fusion. A mix of 99.8% fission and 0.2% fusion, if your fusion is relying on that as its sole source of tritium.
- "Small quantities of tritium are also produced by CANDU-type nuclear reactors—on the order of 100 grams per year for a 600 MW reactor,"
https://www.iter.org/mag/8/56
You'd need 60 kg/year for a 600 MW D+T fusion reactor.
No tritium producing facility separates out nearly all tritium. Tritium separation and handling systems are expensive and demand has been low. It is not that more reactors are needed to meet demand. If demand ramps then the untapped supply can simply be tapped.
I'm not a domain expert, but I believe that figure is the total amount that's created, not separated.
I.e. this language:
- "Ni et al (1) estimate that one CANDU 6 reactor can produce 130 g of tritium per year, but this is based on physics, not actual production data."
https://scientific-publications.ukaea.uk/wp-content/uploads/...
ref. (1) is https://sci-hub.se/http://dx.doi.org/10.1016/j.fusengdes.201...
It's just not a physically efficient process. Heavy-water reactors weren't optimized to produce tritium; it was an unwanted contaminant.
Fair enough, perhaps I was oversimplifying with my example. It seems from the OP the plan is to transition to breeding the tritium in fusion reactors, and that we currently have enough fission-produced tritium to plausibly bridge to those fusion-based processes. And the concern is that the fission reactors might shut down before we bootstrap the fusion reactors.
Still, as I said originally, it sounds like keeping our current level of fission reactors around should solve the bootstrapping problem.
> The simple phrasing of fission as "dirty" really shows the quotee's biases.
And I think their failure to really understand fusion power either. The sort of fusion reactors we build first will produce tons of neutron radiation, which over time will turn the whole reactor itself into radioactive nuclear waste.
Being triggered by the use of the word "dirty" for fission reactors, in comparison with fusion reactors no less, is far more telling than the use of the word. It creates radioactive waste. Creating waste is dirty. The promise of fusion is not to do this. Requiring the former for the latter is a strange proposition when viewed threw the only lense that makes sense for fusion power: cleanliness, the absence of dirtiness.
The love for nuclear power some internet communities exhibit has far left the realm of the science people often invoke as their reason and gone into full-on scientism. Nuclear scientists have respect for radiation. They wouldn't take offense with the mere mention that it has unwanted byproducts. They built and ran a couple hundred reactors for a few decades, and only two of them managed to render large swaths of the landscape into uninhabitable wastelands, which is quite a feat. But it was only possible because they didn't minimize the danger with the sort of I-would-love-a-reactor-in-my-backyard attitude that seems to be prevalent now. Which is, by the way, not only getting the science wrong, but also the politics: nuclear power is out not because it is dangerous, but because it is too expensive and, at this point, too slow to build.
While science bros have been huffing isotopes, actual scientists, with the help of some eerily effective subsidies, have improved solar and wind power and battery technology to the point where it is competitive and scalable not just to replace nuclear power, but even coal. Why people keep making the same arguments as they did a decade ago, a time span in which those technologies became 80-90% cheaper and more efficient, cannot be explained by the natural sciences.
There's a lot of bad thinking in that one sentence.
All or nothing. We must have completely clean power or it has no value.
Not using comparison. How does it compare to other sources of energy, (including solar which is built in facilities using coal power).
Fission is much cleaner than coal power plants in the Nuclear isotopes that are released into the air and we can contain nuclear waste pretty well.
Coal is on its way out, so is not a sensible standard of comparison.
At some point, we will have enough solar/hydro/wind etc that they won't be built using coal power... Right now it's a necessary yes, in the future no.
In a way, that last (...) is also a very black and white way of viewing things.
>In a way
In what way is it black and white view of things?
Solar energy production is not 100% clean. It never will be regardless if coal is used or not. That doesn't mean it's bad. The goal isn't purely clean energy. The goal is improved sources of energy.
Hopefully coal isn't used in the future. But things don't appear to be on track.
https://www.carbonbrief.org/china-briefing-17-march-2022-bei...
Unfortunately, because black and white thinking and evaluating energy sources without comparing them has resulted in a shortage of natural gas (thanks to fossil fuel divestment and ESG) and energy producers falling back to coal. The worst possible source of energy.
It's just shit popsci journalism. Better off reading The Register.
If anyone was wondering if SPARC and ARC care about this, SPARC onsite tritium inventory is planned to be fairly low: just 10 grams (not kg) in this 2018 SPARC paper[0]. I would also speculate that 200 kg/year sounds a little bit too high, although I can't find an ARC paper to corroborate (the magic words you want are "total on-site tritium inventory").
[0] https://www1.psfc.mit.edu/research/alcator/pubs/APS/APS2018/...
ITAR should be shut down. Straight up. It's a complete waste of taxpayer funds taht holds no prospect of producing commercially viable power. Its design constraints were decided decades ago. Since then science and engineering has advanced a lot.
I'd love if it fusion became commercially viable but I'm doubtful it ever will. At the least the kind involving fusion atoms in a plasma for all the documented reasons, most notably plasma turbulence and the power loss and container damage from neutron escapes.
I'm not that concerned about a shortage of tritium. That's a solvable problem. In fact we probably need a variety of breeder reactors for things like this and producing plutonium for deep space probes anyway.
Fusion is a trap for many because it seems so easy. I mean the Sun is doing a lot of it. But the Sun is relatively inefficient (which is compensated for by mass) and it solves the containment problem with gravity.
Well, for all practical purposes, ITER was shut down.
https://www.world-nuclear-news.org/Articles/ITER-tokamak-ass...
https://www.reuters.com/article/us-france-nuclear-fusion/ite...
I'm not sure about the scale here, but is it really as crazy as the article says to use tritium that is formed from fission? What's the ratio of fusion:fission energy you'd need? I can't imagine even if it was 50% or 25% that it wouldn't be worth doing seeing as you'd just be fuelling a clean energy source from the waste stream of another energy source that doesn't produce CO2.
The reaction is supposed to be self-sustaining. The reactor walls are supposed to emit more than enough tritium to satisfy your needs.
Whatever you bring from outside is just to bootstrap it once you turn it on. (I imagine they are not collecting the tritium between runs, but it's something you are expected to do.)
Wait, so then at _whatever_ cost, the cost of producing Tritium is sorta moot, right? Whether it's building reactors or investing a tonne of energy, the cost of creating the amount of tritium needed is met with theoretically infinite profits?
Yes, in theory. On practice the problem is that the ITER doesn't recover enough tritium for economical reasons, and thus needs a constant supply of it for running its experiments.
There is another, unrelated issue that if we decide to scale (H + D) fusion power, for decades we will need more tritium than they can generate.
There will never be any marketable fusion power at all, never mind "infinite". Power from Tokamaks necessarily costs at least 10x power from fission, and fission is already not competitive, and gets less so each year.
??? Fission is incredible profitable. It's the only source of reliable electricity we have (with a negligible CO2 impact).
The only reason fission isn't more profitable is politics. Politics are making investment and research into fission needlessly costly.
Fission is grossly uncompetitive. That's why there's never been a single merchant fission power plant built anywhere in the world.
What county are we talking about here?
All. Even nominally commercial ones get a whopping disaster liability subsidy, and decommissioning cost is omitted from the price, but charged to ratepayers on top of whatever actual power they are also paying for.
It will cost at least a $billion to take apart and dispose of Indian Point, shut down recently because it was leaking radioactive stuff into the Hudson.
See, now I know you're just lying because the equation isn't at all the same across all countries. Maybe you don't like nuclear and that's fine but you don't have to lie about it.
It remains the case that NPPs have never, anywhere, been built into a competitive market. They are only built when customers can be forced to pay for them.
So, what's your argument? That people won't buy nuclear energy on an open market or that an open market for nuclear energy doesn't exist?
In Sweden, where I live, about half of our electricity is from nuclear. It's built and operated by a state owned entity called Vattenfall and while they currently have a politically appointed board that is against nuclear they operate (for profit) all of our nuclear reactors. The only reason we don't build more is because they've made it practically impossible (not illegal) to expand nuclear energy through various political motivated decisions. Sweden had a referendum on the continuation of nuclear energy after the Chernobyl accident, we did vote, though by a narrow margin to transition away from nuclear. However, this past winter we had huge supply issues and people ended up having to pay 4x for electricity due to the premature shutdown of nuclear (meanwhile we had to power up oil and gas burning to compensate). Right now, most people in Sweden are of the opinion that we should keep our nuclear reactors. I, together with several others would like to us to expand our energy production from nuclear to prevent a reliance on oil and gas.
> through various political motivated decisions
Politics is how policy is determined. People have tried other ways. Sometimes they worked. For a while.
Diverting money from building out renewables (and transmission lines) to build nukes ensures, at minimum, another decade of increasing reliance on oil and gas, and then paying more for power than you would have for renewables.
Politics aimed at making a specific type of energy unprofitable by taxing it to death is not. It's activism.
Sweden cannot depend on solar alone, we have plenty of hydro in the northern parts of the country and wind doesn't work during winter. Wind also kills birds and insects, en masse.
People have an irrational fear towards nuclear. Fact is, very few people have died because of nuclear energy. If you compare deaths vs produced watts, nuclear is the single safest energy source by several orders of magnitudes.
Also, I don't know if that's a typo or a misunderstanding but we are not talking about nuclear weapons, i.e. nukes we are talking about thermonuclear energy production. These are two different things altogether.
You just go on telling yourself that. The rest of the world will do what it does.
!?!? Lulz. Okay.
> The reactor walls are supposed to emit more than enough tritium to satisfy your needs.
Didn't know that fusion generators produced its own fuel! If it produces more than enough, then the excess tritium is considered radioactive waste?
The kinds of fusion generators that are considered for the near future produce most of their energy as kinetic energy of neutrons.
The energy of the neutrons is transformed into heat by adsorbing them into some shielding walls. The materials for those walls will be chosen to minimize the quantity of radioactive waste that is produced by the extremely intense neutron irradiation, but it is impossible to avoid completely the production of radioactive waste.
So all the fusion generators planned for the near future will generate radioactive waste, but in significantly less quantities than fission reactors of the same power.
Because they produce an intense neutron flux, like the fission reactors, the fusion reactors can also be used for element transmutation by neutron capture, e.g. for producing tritium or for producing lightly-doped silicon crystals for the high-voltage electronic devices (by transmuting silicon into phosphorus).
However, such transmutation applications usually also need the use of a neutron moderator, to slow the neutrons down to whatever speed is optimal for producing the desired isotope, e.g. tritium. For tritium, heavy water can play both roles, of the neutron moderator and of the target containing the element to be transmuted.
You could absorb neutron flux in a thousand tons of molten 6Li/7Li, and then try to separate grams of tritium from that thousand tons of molten, extremely inflammable metal, on a continuous basis. Good luck with that.
Renewables do not incur such operating expenses. Put renewables and a fusion reactor on the grid, and fusion would never, ever win a bid.
"Fusion .. will generate ... less ... than fission"? The whole damn ten-thousand-ton reactor becomes radioactive waste in short order. Fortunately, none will be built, so it is only a theoretical problem.
Hydrogen does not seem to dissolve very well in molten lithium. It is quite easy to separate on the lab, but yeah, the practical consequences of convection currents and putting it through a heat exchanger may change this.
Anyway, I imagine the people studying fusion have an answer to this, since it only requires normal centuries-old chemical knowledge.
I also do not believe fusion will ever be a competitive power source for stationary applications on Earth.
Despite their fabled immiscibility, a few grams of oil would dissolve very thoroughly in a thousand tons of superheated water. The numbers matter.
The people studying fusion are carefully restricting their attention to the immediate problems of getting it to work at all. E.g., ITER will have no lithium blanket.
They figure on building another whole reactor to be completed (initially guessed) 15 years later at (initially guessed) 4x cost to begin tackling practical difficulties of extracting useful thermal energy.
I dug more about this because it's an interesting topic. Basically we don't know how long a fusion generator will last before radioactivity forces its decommissioning because none exist yet, but fortunately it's short-life isotopes, about 50-120 years before they become safe. Orders of magnitude better than fission waste.
I don't know about fusion vs renewables, because renewables are better, but they need a lot of non-renewables to be manufactured. If a fusion reactor lasted 100 years, it would be a much better option than renewables.
The reactor would need to be replaced frequently as the chamber walls and molten-lithium pipes weaken from neutron bombardment, every two years, maybe as long as five. By the time they could build one, there might be some way to make it last ten?
It needs even bigger containment than a regular nuke because reactive molten lithium bursts into flame on contact with air. The oxidized product is an exploding cloud of vaporized radioactive drain cleaner. A thousand tons of lithium make a lot of drain cleaner.
And again, by that time all our power will be cheaply supplied by renewables with no disastrous failure modes, and maintained just by taking bits down and putting up new bits, in shirtsleeves when weather favors it.
> Basically we don't know how long a fusion generator will last before radioactivity forces its decommissioning
That was one of the main questions the ITER was supposed to answer, wasn't it? AFAIK earlier designs were quite short-lived, but some small changes fixed it. We will know how long they last as soon as we don't have an ITER anymore.
It is scheduled to be done in 2035, which means in practice for projects like this 2040 or 2045, and at $25B meaning $30B+. It will surely be abandoned before then, and we still won't know.
What were these small changes that fixed it? Did they have anything to do with the cost going up by 3x?
Anyway, inducing radioactivity is not what would use it up. That just makes it super-expensive to do repairs. It would get used up through neutron bombardment weakening the crystal structure of the metals it is constructed of.
No, it wasn't. ITER uses materials (like CuCrZr) that are unsuitable for a production reactor, ITER will not perform tritium breeding (except in a few experimental modules that won't be sufficient to prove that technology), and ITER will only operate at full power on DT for at most a few weeks total over its lifespan.
Not really an issue though, as tritium has a half life of 12 years, and the amounts produced would be negligible anyway. You could probably release it into the atmosphere harmlessly (not that regulations would ever allow that, though).
In my sibling comment, I calculate 600:1 fission:fusion, for the heavy water reactors they're talking about.
(I think it could be somewhat better if it were a fission reactor optimized for tritium, but I don't know the numbers for that. I think that would entail fast-neutron reactors with enriched ⁶Li blankets -- analagous to what the fusion reactors are planning to do).
>in, … 12.3 years…, half of the tritium available today will have decayed into helium-3.
When I saw this, I thought that sounded odd, shouldn’t the atomic number go down with radioactive decay? but it turns out that in this case what happens is one of the neutrons splits into a proton, an electron and an electron neutrino so the atomic number goes up by one (unlike the more familiar fission reactions of the heavier elements where the atomic number decreases). So much physics I’ve either forgotten or never learned.
This is the standard beta radioactive decay, which increases Z by 1, while the alpha radioactive decay decreases Z by 2 (and gamma decay does not change Z).
For every A (the number of nucleons in a nucleus) there is a ratio between (A-Z) and Z (i.e. between the number of neutrons and the number of protons) for which the mass of the nucleus is minimum.
Any other isobaric nuclei have an excess of mass over the nucleus with the optimal neutron/proton ratio, so they will decay towards it. The nuclei with too many protons will capture electrons or emit positrons, while the nuclei with too many neutrons will emit electrons, increasing the number of protons with each emitted electron, until the optimal neutron/proton ratio.
For the decay products of uranium and thorium, there are always too many neutrons, so the normal beta decay is what always happens.
It is possible to artificially produce nuclei with too many protons, and there are a few such unstable isotopes that are produced naturally, which decay by the reverse beta decay (electron capture or positron emission), where Z decreases by 1 for every captured electron / emitted positron.
For A = 3, the nucleus with minimal mass is helium-3. Tritium has too many neutrons in comparison with helium-3, and it must get rid of them by emitting an electron.
Yea, beta decay is weird. On the other hand, transmutation of the elements!
Title is extremely misleading.
> "Right now, the tritium used in fusion experiments like ITER, and the smaller JET tokamak in the UK, comes from a very specific type of nuclear fission reactor called a heavy-water moderated reactor."
You litterally just need to make more of these heavy-water moderated reactors, which are rare and approaching end of life, but certainly you can build more of them if it was the difference between having endless energy or not.
Ok, we've changed the title to the subtitle above.
One of the main objectives of ITER is to test Tritium Breeding technologies for DEMO. There is no shortage due to heavy water plants shutting down because it was never planes to use Tritium from that source in the first place!
ITER will not produce significant tritium, since most of its walls are not covered with breeding blankets. Most of the neutrons it produces from DT fusion will not hit a blanket module and therefore not breed tritium.
My key takeaways:
* In a perfect world, there would be a more ambitious program developing the breeding technology in parallel to ITER, Willms says, so that by the time ITER has perfected the fusion reactor there’s still a fuel source to run it
* Like many of the most prominent experimental nuclear fusion reactors, ITER relies on a steady supply of both deuterium and tritium for its experiments
* When it’s finally fully switched on in 2035, the International Thermonuclear Experimental Reactor will be the largest device of its kind ever built, and the flag-bearer for nuclear fusion
* And as ITER drags on, years behind schedule and billions over budget, our best sources of tritium to fuel it and other experimental fusion reactors are slowly disappearing
* Right now, the tritium used in fusion experiments like ITER, and the smaller JET tokamak in the UK, comes from a very specific type of nuclear fission reactor called a heavy-water moderated reactor
* “We’re hitting the peak of this tritium window roughly now.” Scientists have known about this potential stumbling block for decades, and they developed a neat way around it: a plan to use nuclear fusion reactors to “breed” tritium, so that they end up replenishing their own fuel at the same time as they burn it
* “Calculations suggest that a suitably designed breeding blanket would be capable of providing enough tritium for the power plant to be self-sufficient in fuel, with a little extra to start up new power plants,” says Stuart White, a spokesperson for the UK Atomic Energy Authority, which hosts the JET fusion project
* “It would be an absurdity to use dirty fission reactors to fuel ‘clean’ fusion reactors,” says Ernesto Mazzucato, a retired physicist who has been an outspoken critic of ITER, and nuclear fusion more generally, despite spending much of his working life studying tokamaks
* “After 2035 we have to construct a new machine that will take another 20 or 30 years for testing a crucial task like how to produce the tritium, so how are we going to block and stop global warming with fusion reactors if we will not be ready until the end of this century?” says Mazzucato
Arthur Turrell's book, The Star Builders, is an excellent overview of the state of the art of nuclear fusion technology. Unfortunately, however, fusion is unlikely to be radically cheaper than other sources.
Can you please stop doing this? I'm sure these comments are well intentioned, but the pattern has become repetitive (https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...) and anything this repetitive is bad for curiosity (https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so...).
HN threads are supposed to be conversations, and conversation involves people interacting with each other.
Okay I will not post these anymore. I might share the summarization algorithm I wrote that enables me to create these quickly, though. Thanks for helping me understand the ethos of curiosity and the diffs as the underlying principles.
Yes - sharing the algorithm would indeed be interesting! Thanks for getting the point so well.
Last week Elon explained that the problem of fusion is that it will be more expensive than solar and wind.
The real question is whether it's more expensive than solar/wind plus the batteries required for dispatchable power.
The answer depends on the reactor design, which Elon doesn't know. There are a lot of possibilities, and if the first ones are too expensive, later ones might not be.
Almost certainly it will be more expensive than renewables + storage (note the importance of hydrogen there.)
The cost of renewables + storage to provide "synthetic baseload" is likely less than fission. And DT fusion is likely more expensive than fission.
https://model.energy/
Yes, we discussed that pretty extensively the other week. It starts out with unrealistic assumptions for fission, including a 25-year lifespan (compared to the actual average age of US reactors of forty years) and twice the discount rate for fission as for everything else. Fix those things and nuclear does better.
It also uses US fission prices, which are higher than in most of the world. On top of that, the US has unusually good geography for both wind and solar. Nuclear is much more competitive in many other countries. One ironic example is Germany, where the model suggests a 100% nuclear grid even at US nuclear costs, as long as the lifespan and discount rate are corrected.
And as I told you last week, the numbers are actually optimistic compared to US (or actual EPR) numbers. In particular, it assumed the reactor cost 6000 euro per kW, which is considerably less than what EPR ended up costing.
And I linked you a paper surveying global nuclear costs, showing much lower costs in many areas and no overall trend of increasing costs. Here's the paper again:
https://www.sciencedirect.com/science/article/pii/S030142151...
Skip down to Figure 12 for a quick summary.
Most of those points that were low were either France or Korea. France with EPR has lost whatever mojo they claim to have had (those earlier cost figures are not verifiable) and Korea turned out to achieve low costs by corruption and omitting safety features.
The lowest, sure, but those are around $2000/kW. The bulk of the points on the graph are still below $4000/kW. That includes Japan, India, and Canada, along with a lot of early US reactors.
Also, do you have a source for early French costs being unverifiable? I don't see where that's mentioned in the paper, so it doesn't seem right to just dismiss the data unless there's another source giving us good reason to do that.
As for the EPR, seems to me the conclusion there is just to not build any more EPRs.
In America the NRC issues a 40 year license to a reactor which then, after a review, can be extended. 40 years is the lifespan of the initial license not the plant.
Cost for energy storage is plummeting even faster than for solar or wind ever did.
True, but that is a moving target.
https://ourworldindata.org/battery-price-decline
Like the stopped clock, even Elon is right once in a long while.
"Precious tritium is what makes this project go. There's only 25 pounds of it on the whole planet."
> There's only 25 pounds of it on the whole planet.
"Because we haven't needed more until now, and it's mostly man-made."
There wasn't any plutonium on Earth, either, until we decided we needed some.
Actually, when the Earth was formed, it contained a non-negligible quantity of plutonium (supernovae produce all the elements until Z=100, much over the Z=94 of plutonium, but the heavier elements had already decayed before the interstellar dust reached the nascent Solar System).
Because the longest-lived isotope of plutonium has a half-life close to 100 million years, so some 45 halvings have happened since the Earth formation, almost all primordial plutonium has decayed by now.
A few atoms of the primordial plutonium are still around us, though they are much too few to be easily detectable (there have been claims that some very sensitive experiments have detected them).
Just to provide the other half of the concern around how little there is.
...it’s estimated that working fusion reactors will need up to 200 kg of it a year
The working fusion reactors will produce enough to not need additional tritium, it is a self-sustaining reaction after all.
What about in near earth asteroids?
Tritium has a half-life of about 12 years, meaning that it essentially doesn’t exist naturally. It’s all man made.
I thought the end game was aneutronic fusion using lithium and deuterium anyway creating only charged particles instead of high energy neutrons that are dangerous and damaging to the reactor. If nuclear fusion ever wants to be commercially viable, it must not depend on tritium.
Helion is working on a deuterium/helium-3 reactor, which if it works will produce only 6% of its energy as neutron radiation. YCombinator was an investor. They've run six reactors and are building a seventh now for a net power attempt in 2024.
There are also at least four companies working on proton-boron fusion, though all but one are very small. (TAE is the exception.)
Except they need a DD reactor to make the 3He to fuel the D3He reactor.
The plan is to do that in the same reactor.
D-3He. But 3He comes only from decaying tritium, so same problem.
At least D-3He might possibly be made to produce economically competitive power, if there were any 3He to burn in one. But it might be useful in space probes.
Whimsy. Is there a sequence of fusion technologies where the previous one lights the next one and if the current one goes out we're fucked?
Can't an operational fusion reactor breed tritium? If so we just need enough tritium to start one.
The article covers that.
> Tritium breeding was originally going to be tested as part of ITER, but as costs ballooned from an initial $6 billion to more than $25 billion it was quietly dropped. Willms’ job at ITER is to manage smaller-scale tests. Instead of a full blanket of lithium surrounding the fusion reaction, ITER will use suitcase-sized samples of differently presented lithium inserted into “ports” around the tokamak: ceramic pebble beds, liquid lithium, lead lithium.
> Even Willms admits that this technology is a long way from being ready to use, however, and a full-scale test of tritium breeding will have to wait until the next generation of reactors, which some argue might be too late. “After 2035 we have to construct a new machine that will take another 20 or 30 years for testing a crucial task like how to produce the tritium, so how are we going to block and stop global warming with fusion reactors if we will not be ready until the end of this century?” says Mazzucato.
$25 billion... thinking about how much money we've dedicated for active warfare in the last 2 months alone... clearly we have our priorities.
I struggle to understand this type of comment.
You can't respond to the bad guys with a plea for them to stop what they are doing because you would rather spend the money on something else.
That isn't to say that battles should not be picked carefully, just that sometimes you don't have a choice and have to deal with a situation and spend lots of $$$ and sometimes blood in order to avoid a worse situation. Even in the context of "last 2 months alone" it isn't clear what specific action is being referenced so the comment is just too abstract, IMHO.
In some cases it makes sense to engage, in others it doesn't. There is no single correct answer unless you want to enter into a discussion of pacifism.
That is not what that comment says. It clearly means money can be spent when we go to war, or when we need pandemic money, but a measly 25billion in comparison suddenly is “a lot”. If we want fusion, we have to invest.
We do have a choice about Ukraine, just as we had a choice about Syria, Libya, Iraq, Yemen, Afghanistan, Vietnam, Honduras, Guatemala, El Salvador, etc. We are making the wrong choice now, just as we made the wrong choices before. Although we kill lots of people, many of them innocent rather than "bad", we never actually "avoid" worse situations. In cases like Libya our intervention has worsened human life by every measure. In other cases we might have delayed inevitable events somewhat (e.g. Vietnam couldn't go to war with China until it finished beating us). The "specific action" in every case is spending public funds, which is the purpose of the USA military, intelligence services, diplomatic corps, and news media, and has been since the Korean War. Insofar as they affect security at all, our military efforts usually reduce it.
$25 billion is about 9 Virginia-class submarines. The US has already built 22 and plans to build 66. Granted, they're very nice and important submarines, but it still makes $25 billion seem like chump change by national project standards.
I'm very unimpressed by the "we must only consider short term solutions to global warming" idea.
We don't know the future, and we keep being surprised by it!
if we want to significantly curb global warming, long term solutions aren't where we need to focus effort
Then it's a good thing we're not focusing effort on long-term solutions. We're spending a lot more money on rolling out renewables than we are on fusion research. That doesn't mean we should cut out long-term solutions entirely.
If we want to fund more renewables than we are now, then the place to cut back is the many fossil fuel projects that we're still investing in. Until we've done that, I think any positive effort deserves applause instead of complaints about focus.
Oops missed that.
ITER is not necessarily the best approach to fusion, although it's the best funded.
In any case if we can't breed tritium than we either need to shoot for higher energy D-D fusion or some other reaction or fusion will never be cost-competitive.
Is there any other approach to fusion than ITER?
I mean fusion capable of practical power generation.
D-T fusion is the easiest, and yet super hard. Tokamaks are the only design that we know how to build in order to meet the goal, with maybe stellerators in second position. Inertial fusion work for scientific and military experiments, but are far from being a usable power source. Things like fusors and its derivative are great hobby projects with a few limited practical applications, but we are not even sure if it is physically possible to produce more energy than we put in. As for LENR (aka. cold fusion) we are essentially at the "thought experiment" stage, when it is not a scam.
One other idea that may work with current tech is to dig a large cave, line it with really thick material and detonate hydrogen bombs inside it, extracting energy from the heat of the explosion. I don't think I need to tell you that even if we can do that (unsure), we certainly shouldn't (absolutely sure).
Or, take, advantage of that really big fusion reactor we already have and makes us go around in circles.
Most conservatively, there are tokamaks that use more modern superconductors, able to support much stronger magnetic fields. Tokamak output scales with the fourth power of the magnetic field, so that allows the same output as ITER from a much smaller, cheaper reactor. The MIT spinoff CFS is doing this, along with Tokamak Energy in the UK. CFS is shooting for a net power attempt in 2025.
There are also various alternative designs, like Zap Energy's z-pinch, General Fusion's magnetized target fusion, and Helion's field-reversed configuration. Helion is attempting hybrid D-D/D-He3 fusion, the other two are D-T.
All the DT approaches suffer from poor volumetric power density, for fundamental reasons independent of the details of magnetic fields or confinement schemes. For that reason I feel Helion's approach is the least dubious.
Ironically, this is perhaps the smallest problem facing practical civil fusion power.
Probably the biggest problem is wasting time and budget on such dead-end technology as Tokamak, which can never in anybody's wildest dream be competitive with renewables, even given abundant tritium. But the conceivably useful D-3He aneutronic fusion depends on a supply of 3He, which is uniquely a product of tritium decay, and thus also depends on a tritium supply.
Thus D-3He would not be useful for baseload civil power, either. But it could be the only useful power source for projects in the outer solar system, for which a much smaller amount of 3He would suffice. It is hard to imagine another power source adequate in the outer solar system (aside from pB11 fusion which would be super if it is actually possible at all).
(No, mining 3He from the moon would totally not work at all.)
"tritium for its experiments".
The whole point is to reach a Deuterium or Hydrogen reactor with a light lithium ignition in a lot of cases which would be easier to fuel than Tritium due do problems extracting it.
Wasn't this the setup for Spiderman 2?
Tell that to the Sun. We already have a fusion reactor sufficient to meet all of humanity's energy needs, it's a gravitationally contained fusion reactor with a projected lifetime of at least one billion years, so why not just rely on that? Seems to have done wonders for the biosphere for the last one billion years, hasn't it?
You are spot on. The world will be powered by renewables before fusion ever sees its first commercial watt produced.
https://news.ycombinator.com/item?id=31428469
https://pv-magazine-usa.com/2022/05/16/a-fate-realized-1-tw-...
Moreover, if we would really ever become able to produce by nuclear fusion a quantity of energy comparable with the energy received from the Sun, then that would cause by itself a great climate warming, so nuclear fusion is not a solution against it.
If the quantity of energy produced by nuclear fusion would remain negligible in comparison with the solar energy, then there is no need for it.
While on Earth using the nuclear fusion makes little sense, mastering it could enable the exploration and even the colonization of the Solar System.
Instead of asking oblique rhetorical questions, you could actually make a meaningful statement.
It seems like every fusion post is bound to have at least one commenter point out that the sun is a working fusion reactor, as if literally anyone in these threads will learn something from this observation.
Roughly $50 billion has been spent globally on fusion research since the 1950s with nothing material to show for the effort; at what point do you stop throwing good money after bad? This strikes me as the learning from these posts.
I think you make an excellent point that fusion research is underfunded. NASA budget since the 50s is ~$1,400 billion — almost 30x what’s been put into fusion research. We’re asking fusion research to produce “free, clean, and carbon-free base-load electricity forever.” Seems worth a NASA-level of investment to me.
You could use the same logic to claim perpetual motion machine research is underfunded. The likelihood of the research leading to a useful result has to enter into it somehow.
Saudi Arabia alone exported almost $100 billion in crude petroleum in 2020 [1]. That was significantly less than the previous year.
Given these scales I'm not really sure $50 billion is a lot of money for the entire world to spend on an energy R&D project. In fact, that number seems surprisingly low, do you have a source for it?
[1]: https://oec.world/en/profile/hs/crude-petroleum
I'm sure it is difficult to decide that since, as pointed out, there is a working example staring at us every day. So it always feel just out of reach.
Intel has a capex budget of $27 billion just for 2022, so you don't really understand scale or have a point.
Intel has working products, customers, shareholders, and fundamentally, accountability for that research spend. Results driven research funding is not unreasonable, unless you want to classify this research in the same vein as particle accelerators and a curiosity with no expectation of success (which is fine; just don’t sell as an energy silver bullet where there’s no evidence it can be delivered on). Hope is not a strategy nor a cost justification.
Just because the semiconductor's productivity gains have been massive on a short term time horizon, does not mean that fusion research has been a waste, or that is not on track to "deliver". Fusion as a technology is a long term bet and requires much more capital expenditure, for little short term return, then even semi fabs (which are notorious capital sinks).
Your mention of cost justification is ignoring the bigger picture that our economic system is setup to benefit public companies like Intel, and not grand research endeavors.
As an exercise to the reader, imagine what organizations/companies would exist if the contemporary economic incentive structures were different.
There is in fact no "track" with commercially competitive fusion-generated power at the end of it, tritium or no tritium. It's great that plasma physicists are being employed and enabled to do research, but that could be done much more cheaply and effectively by not spending on ITER.
Fusion reactor research is kind of interesting, I suppose it's making alchemy real in a way. Stars make things like helium and lithium from raw protons and electons and neutrons, apparently. and if humans could master that we could basically solve a lot of matter limitatation problems by just making whatever elements we needed at whatever scale from nothing but hydrogen as the raw material (maybe some helium too). That's basically all sci-fi at present, but who knows.
As far as making fusion reactors to boil hot fluids to drive steam turbine-generators to power the electrical grid... doesn't seem too likely. High-efficiency monocrystalline Si PV panel fabs would be a better investment.
The sun is a great fusion reactor, it's just too bad the transmission lines go down for so many hours every day.
The Sun doesn't shine for half of the day in most places on Earth. Or when there's clouds.
Known to cause cancer, tho. And may be implicated in global warming.
> There are other ways of creating tritium but these techniques are too expensive to be used for the quantities required, and they will likely remain the reserve of nuclear weapons programs
Too expensive for clean power, just right to threaten the world
Takes less for the latter.
Just a quick reminder, we already have practical fusion with tens of thousands of years of runway available to us today. We choose not to do it because it sounds dangerous and it’s not politically expedient.
For those unfamiliar, I am talking about Project PACER. The fusion reactor proposed by Teller after the creation of the thermonuclear weapon. It may sound fanciful but it’s based on a simple precept. We can already induce fusion reactions, albeit in an unstable and explosive fashion. What if we took that warhead, surrounded it with a giant underground chamber made out of steel several feet thick, and let it explode while molten fluoride captured the heat?
Their work conclusively shows that this can be done, and that molten fluoride salts could capture most of the neutrons to prevent embrittlement. A single such facility could power the entire country. Oh and it could be configured to create Tritium in the process.
https://en.wikipedia.org/wiki/Project_PACER
The project was terminated because it was "bound to be controversial" and would "arouse considerable negative responses."
The math is sound. The concepts are sound. We could solve the comparatively minor engineering challenges and build one today while waiting on the the breakthrough needed for controlled, continuous fusion.
It lacks the key advantage of fusion reactors over fission: not contaminating its working fluid with radioactive isotopes. For something like PACER, you have to extract the heat by running the hot fluoride through heat exchangers to run steam turbines. This is difficult and expensive to make safe. Like with conventional fission reactors, you have to be extremely sure your heat exchangers will last 50 years with zero leaks, because you can't touch them once the system has been running. And leaks are extremely dangerous. So every weld has to be triple-inspected and so on.
A second disadvantage is that the parts would undergo constant thermal cycling. Conventional reactors are run at a very steady output level to handle base load, because turning them up and down regularly would cause the moving parts to fatigue and crack over time.
The project was terminated because there were formidable technical issues, it wasn't economically profitable, and there was a real possibility of catastrophic failure that could not be mitigated.
https://books.google.com/books?id=4QsAAAAAMBAJ&pg=PA18#v=one...
> Dropping about two bombs a day would cause the system to reach thermal equilibrium, allowing the continual extraction of about 2 GW of electrical power.
So the idea is to drop 2 nuclear bombs per day to get about as much energy as one gets from a pair of nuclear fission reactors? I seriously doubt that's cost-competitive with fission power.
And, fission is itself not competitive anymore.
Competitive with intermittent sources backed by fossil fuels? No, but those emit carbon emissions. And we lack the ability to add significant amounts of energy storage, so wind and solar will never conceivably break free of it's dependence on fossil fuels during non- production.
It's the most competitive non-intermittent and geographically independent source of carbon-free energy. Because it's the only such source.
And yet, not competitive. So, there is something missing in your model. It is for you to figure out what is wrong.
It's not competitive with a power source containing fossil fuels. And there's no feasible way to run a grid composed of wind and solar without fossil fuels. Ignoring the fact that wind and solar generation is really wind, solar, and fossil fuels, to offset the intermittency is naive.
In areas without hydroelectric and geothermal potential, nuclear is the most competitive carbon-free and non+intermittent option. Because it's the only option. That's why for all your insistence that nuclear is uncompetitive, it produces more electricity than wind and solar combined.i
See, you got the wrong answer again.
Renewables plus local storage, transmission line, and/or ability to burn imported ammonia or hydrogen suffices, and at radically less cost, with no risk of rendering large areas uninhabitable.
Storage at anywhere near significant levels does not yet exist, and might not be achieved in the time necessary to curb the worst effects of climate change. Ammonia and hydrogen storage has been proposed, for decades, yet remains out of reach at the scales necessary to make renewables viable.
Wind and solar is really wind, solar, and fossil fuels. Assuming that we'll be able to replace the last item with energy storage is betting the future of our climate on an engineering breakthrough. No such gamble exists with nuclear, countries like France have successfully produced nearly all their electricity with nuclear power for decades.
You keep repeating this, but you know it is not true.
Some of the heartburn about PACER is that there are failure modes that can only be described as catastrophic.
No shit.
Turns out a daily detonation of a fusion bomb tends to wear on things and when those things fail... you've just detonated a fusion bomb.
They actually want to detonate a H-Bomb every 45 minutes, all day every day. 32 nuclear explosions every day.
One does have to appreciate how these guys took anti-proliferation concerns with the nuclear industry and said "fuck it, everyone knows we're only doing this to make bombs, so lets make a shit ton of bombs". No more concerns about terrorists getting their hands on some yellowcake and making a dirty bomb. Now they have a full up H-Bomb factory moving so much product that security can get complacent.
And we can expand this out to every nation so everyone gets a nuke factory to keep the lights on. :D
It's so widely impractical.
We’re facing a catastrophe. I and others have described elsewhere that the path we’re on is much, much worse than even the most dire of predictions the IPCC makes. https://news.ycombinator.com/item?id=30947756
Teller et al anticipated your objection. It’s why the reactor is supposed to dig into sold rock. If there’s a catastrophic failure then it’s yet another subsurface nuclear test. And the more advanced designs considered for Project Plowshare produce minimal residual radioactivity. All of the products dissipate within 6 months.
So, in the worst case scenario, the facility gets buried under tons of rocks, far away from any water. And the residual radioactive products rapidly decay into being harmless with 6 months. Any induced radioactivity from the neutrons produced during the explosion will follow a fairly predictable pattern as well.
This can be done.
In exchange we get a reactor that creates nearly limitless power for entire countries.
Or we could chose a number of WAY safer fission reactors for the same cost and same power output (Pick your favorite Gen IV reactor).
We also don't end up creating a literal nuclear weapons manufacturing plant in every nation that wants to use this (since the "fuel" for this reactor is constantly detonating nukes).
Why not Gen III+, these are ready to go whereas most Gen IV reactors are still in the drawing board possibly early prototype phase.
I'm fine with either to be frank. I like that Gen IV reactors should have much cheaper deployment strategies.
Anything is better than the "drop a nuke in the hole" plan. Both Gen III+ and Gen IV reactors can hit the market before all the red tape is cut for prototyping the hole bomb.
Worst case scenario is you blow the doors off of the facility and tons of superheated radioactive fluoride salts are blasted into the air, along with the vaporized particles of all of the workers and the fissile material in all of the bombs in the staging areas.
The same line of reasoning says that we should build conventional light- or heavy-water reactors. The risk is minimal. And they're (a) tested and (b) much cheaper than PACER.
The advantage of a PACER setup is that you get a lot more bang (heh) per kg of uranium than you do out of a fission reactor. But the cost of uranium is not currently a problem with our fission reactors. We do have a problem with radioactive waste, but even that is way more political than it is technical.
I wonder which two senators are going to be ok with detonating 32 bombs in their state every day? This isn't the 50s, NIMBYs know how to make your life a living hell when trying to do anything nuclear.
Future fission reactors both don't need uranium (thorium reactors) and use less of it while waste that isn't radio active for long (breeder reactors).
Thorium turns out not to be the solution to any problem.
One problem it solves is making reactors that can't produce material for nuclear weapons. That's pretty important if we want to deploy reactors outside the few countries that already have them.
I live near Indian Point, recently shut down. They tried thorium back when it was new. It cost too much then. Nukes of any stripe are not competitive now, and get less so every year. Thorium cannot save them.
Solutions that rely on a steam turbine generally lose to those that do not. A need to fool with fuel and security cost even more. Account for the disaster insurance subsidy and decommissioning cost, and they come out a marked drag on society.
That is, if you manage to complete one before it gets cancelled because renewables are already doing the job more cheaply than it can. We do better not to spend the initial $billions on what will never produce any marketable power. No such money is ever returned.
A nuke that runs only at night costs almost twice as much per kWh.
It's possible the economics have changed since the 50s. The non-proliferation argument certainly has: in the US in the 50s, making plutonium was considered a useful feature of power reactors.
That does happen, but has not in this case.
> We’re facing a catastrophe. I and others have described elsewhere that the path we’re on is much, much worse than even the most dire of predictions the IPCC makes.
There are a lot of processes we don't fully understand so your claim is hard to substantiate. Also, if that was the case then a lot of people would probably just accept their fate.
I suspect worst case scenarios are more about earthquakes either natural or human induced
But surely the payoff would justify a 10-20x overbuild for the containment and research into extremely small payloads, no?
It would have meant the end of nuclear arms control and non-proliferation efforts, an already difficult process. So yeah, that tends to arouse considerable negative responses.
Isn't the problem that the fuse for a fusion bomb is a fission bomb, and a fission bomb very violently disperses lots of radioactive material? What am I not getting?
It’s a sealed chamber underground. And the amount of fallout can be controlled. Some fusion designs are “cleaner” than others w.r.t. fallout.
From the wiki,
> A typical design called for a 4 m thick steel alloy blast-chamber, 30 m (100 ft) in diameter and 100 m (300 ft) tall,[9] to be embedded in a cavity dug into bedrock in Nevada. Hundreds of 15 m (45 ft) long bolts were to be driven into the surrounding rock to support the cavity. The space between the blast-chamber and the rock cavity walls was to be filled with concrete; then the bolts were to be put under enormous tension to pre-stress the rock, concrete, and blast-chamber. The blast-chamber was then to be partially filled with molten fluoride salts to a depth of 30 m (100 ft), a "waterfall" would be initiated by pumping the salt to the top of the chamber and letting it fall to the bottom. While surrounded by this falling coolant, a 1-kiloton fission bomb would be detonated; this would be repeated every 45 minutes. The fluid would also absorb neutrons to avoid damage to the walls of the cavity.
You can see the general design here, https://nextbigfuture.s3.amazonaws.com/uploads/2016/01/zyrEF...
You control the detonation with either an engineered or natural cavity filled with fluid. You can then use the fluid as a big thermal reservoir to run steam turbines. Per wikipedia:
>"Dropping about two bombs a day would cause the system to reach thermal equilibrium, allowing the continual extraction of about 2 GW of electrical power."
Now... the part you're not getting is that if you can do all that, you can almost certainly just use conventional fission power generation, which is what we really, REALLY need to be doing anyway.
Yes, conventional fission would be much cheaper to operate. But it, also, is no longer economically competitive.
So long as carbon-emitting sources are allowed to be used in the mix. That’s the real problem here.
Carbon sources will have been long since priced out of the market before you could finish building a nuke.
Great information! Project PACER was certainly an attempt to introduce fusion reactors with the technology we currently have Mastery of. In the early 1970s, both LANL and LLNL National Labs had PACER fusion programs. Dr. Ralph Moir was the project leader for this program at LLNL. Inertial Confinement fusion is "controlled fusion" to the very same extent as Magnetic Confinement fusion (the same fuels and fusion reactions are used and the same nuclear waste [stable nonradioactive Helium] is produced.
(more info) What are the reasons that nuclear fusion power generation is not yet realized? https://www.quora.com/What-are-the-reasons-for-nuclear-fusio...