What is a molten salt reactor?
thmsr.com
thmsr.com
If they still don't exist, then surely that suggests it doesn't work, doesn't it?
I'm not an expert though, just interested in the topic. I read up quite a bit on MSR and LFTR a decade ago and concluded that it was really interesting tech that can absolutely work but just never got enough interest for someone to "go big" with it. The wikipedia article[0] has a recent developments section that suggests the tech is quite viable.
[0]: https://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reacto...
Insanity.
What do you mean by "modern society"? According to the IEA, "energy demand per capita is likely to remain at current levels for the next 25 years. In other [words], peak per capita energy consumption may have already arrived".[0]
Most "modern societies" have less than replacement fertility levels, so energy use is only increasing because the population is living longer, and because of immigration. To give some aggregate numbers for a set of modern societies: "The EU-27’s population is projected to increase from 446.8 million in 2019 and peak to 449.3 million in 2026 (+0.6 %), then gradually decrease to 441.2 million in 2050".[1]
[0] https://www.businessinsider.com/bernstein-says-peak-energy-p...
[1] https://ec.europa.eu/eurostat/statistics-explained/index.php...
My next stop is 14 kilowatts peak and 36 KWh. With any luck I'll be able to leave my pool warm for 6 months of the year and remain off-grid.
Then I replaced the inverter with phocos one so that it will work without batteries in off grid mode.
I have thought quite a bit about water batteries, I want to install 200-400 Litre water solar heater so that my electric energy is reduced even more.
No batteries yet because they cost a fortune.
My idea was to heat say 500 Litre water tank in my basement with solar water + solar electric and pass that water through the central heating piping through he home but installer tells me the heat won't be there in this "water battery".
Build-out of renewables will increasingly displace fossil-fuel generation, then (as that is exceeded) bank energy in storage systems (batteries and pumped hydro, short-term, other tech for longer term). We will need a lot of new transmission lines to trade power between current users, current generators, and storage.
None of it requires new physics, although improvements in catalysts will improve round-trip efficiency and cost of storage systems and synthesis, and new chemistries will improve cost and efficiency of new photovoltaic build-out.
There is no place for nukes in that world. They cost way too much to compete on a fair playing field.
https://en.wikipedia.org/wiki/Crescent_Dunes_Solar_Energy_Pr...
First, there are two main groups of molten salt systems. One group uses generic salt to transport heat. This usually provides efficiency gains over water based systems. These are the systems that might leak sodium and it's no big deal.
The 2nd kind of system uses a salt with the fissile material dissolved in it. This is what the article is about. Leaks in these systems are not an option. The molten salt in this case slowly attacks any metal it comes in contact with. The tanks, tubes, etc. are designed with a large safety margin and constantly monitored. The salt chemistry is also monitored for signs of the materials the storage vessel is made of.
Alternative would be to drain it into a holding tank and, what, send somebody in to fix it? Who?
You identify the operational error in salt chemistry that has lead to losing some of the storage vessel material, and then you perform engineering analysis on the new resultant factor of safety. If necessary, next fueling cycle you shut down the reactor and perform remediation actions.
Almost all largely workable decades ago before we had e.g. laser welding, modern remote welding, industrial robots, etc. Of course things are better now. (Also, of course, we'd have to learn a lot operationally to actually do it).
Still, obviously these are procedures one would like to not have to employ, as they're likely to be very expensive and troublesome. They provided ample fuel for your concern trolling while I slept and couldn't answer, though, and then for you to "conclude" that there was no answer because the person answering in my stead didn't offer one. Yuck.
Salt chemistry monitoring is a critical part of a MSR operation. The fissile material is slowly exhausted in the reaction and needs to be replaced, while the byproducts need to be removed. The nuclear reaction causes some transmutation of every element it irradiates, which means you get a predictable but diverse set of contaminants that need to also be removed.
The molten salt corrodes everything it comes in contact with, and the radiation also degrades the materials in wild ways. One study I read estimated that directly exposed tungsten would transmute into rhenium at the rate of 1% per year, and that the newly created rhenium would transmute into osmium at the same rate. Basically, it will take an army of people much much smarter than me to plan for all the issues that might come up during the operation of a MSR.
There are many startups backed by billions of dollars trying to find a good solution. One of my favorites simply designs in 8 containment vessels and a crane into the reactor chamber. They plan to just pick up the top of the reactor and move it into a new vessel every 7 years or so.
Sorry can you back this statement up with more than "it's safe, trust me"?
I'm not knowledgeable enough to say if this statement can be accepted at face value. History has shown that's not enough.
But to me, any system that leaks by accident is a disaster waiting to happen on time scales that power plants are expected to operate on.
In this case, leaking molten sodium merely causes a nontoxic metal fire. Definitely in the category of "not fun", but not the end of the world either. Just dump some sand on it and wait for it to cool down.
Leaks of molten salt nuclear fuels are an entirely different category of industrial disaster. A nuclear accident at best, and a large-scale disaster at worst.
It's like the difference between a water truck having an accident and spilling water on the road and a damn bursting and flooding a city.
One makes for a funny picture on Reddit, the other gets the national guard called up to deal with the emergency. Both involve spilled water.
Fluoride in toothpaste is toxic. You have to spit it out, not swallow it. The small quantities used are fine, but if ingested a significant amount, you'd get a "not fun" trip to hospital.
There are systems that use molten salt to transport heat. Several types of power generation systems are more efficient above the boiling point of water. The most famous of these would probably be solar collectors. The efficiency gains are higher at increased operating temperatures, so these systems are usually pushed to their limits. These can leak without causing an international incident.
Molten salt reactors, MSRs, are nuclear reactors that use a liquid fuel in place of a solid one. As far as I know, only a handful have ever been built and reached criticality. These were all done in the 50's and 60's. These systems have secondary and probably tertiary containment vessels in the case of leaks.
These are two very different, but often conflated, systems. Part of the reason for this is that many MSR designs use a secondary molten salt loop as a temperature step-down.
Here is the Wikipedia diagram for a MSR. Note the fuel salt loop, the molten salt coolant loop, and the steam turbine.
https://en.wikipedia.org/wiki/Molten_salt_reactor#/media/Fil...
You can use water, sodium, lead, fluoride salts. All have their different issues.
I always had the same suspicions about the pebble bed reactor boosters. That was a design that was always sold as being inherently safe and self-moderating, with the huge, huge asterisk that if any oxygen or water ever gets anywhere near the fuel the whole thing will explode and then catch on fire, which seems like a pretty severe drawback. Any time you see a claim that a reactor vessel "does not contain" either water or oxygen, just mentally translate that to "is not designed to contain" or "does not initially contain" before reading further.
Just to clarify, reactors cooled by liquid sodium are not molten salt reactors but rather belong to the class of reactors often called "metal-cooled" (sodium is a metal, not a salt, see).
The tl;dr on the page is missing a crucial word near "which", making the sentence nonsensical to me.
By the time any production molten-salt reactor design could get proved out and the first commercial one built, renewables + storage will be providing all our power for much less money than it ever could.
But we can waste a lot of $billions on it that could instead go to build out a hell of a lot of panels and wind turbines.
This will effectively render the issue moot, the few people in those regions could burn fossils and it wouldn't really matter. But it would be cheaper for them to import green energy.
They are importing fuel now, and may continue. In the future the fuel they import will be cheaper if synthetic. Or they may rely more on transmission lines, and stockpile synthetic fuel for backup in case of outages.
People everywhere will do what works best for them where they are. As synthetic fuel cost drops below extracted and refined hydrocarbons, people will simply stop buying the latter. Forward-looking sunny tropical countries will do well exporting synthetic fuel to places where the wind or sun flags.
But in the near future, synthetic methane will be cheaper than mined natural gas. More expensive than ammonia, necessarily, because it needs carbon.
They seem to do OK importing liquid fuel. Dunno why they would have to stop.
I agree with you that we don't need nuclear power to solve the climate change problem. But once we are done with that, we will continue to live. Research in new types of nuclear power will yield benefits, even if on a timeline that is beyond the target date for net zero emissions (2050 or so).
pB11 fusion, ultimately.
We have some lessons from the Energiewende in Germany, which turned out much more expensive than promised. German Green minister Jürgen Trittin assured the German public in 2004 that support for renewable energies is going to cost them "one ice cream scoop per month" [0]. Which was so wildly off-mark that you can only laugh about it bitterly in 2022.
Now it is possible that molten salt reactors are a waste of money, but I would still prefer having more options open for the future. Especially your idea that storage will be cheap needs to be tested in reality first. Currently, storing of electric energy is darn expensive.
[0] https://de.wikiquote.org/wiki/J%C3%BCrgen_Trittin
Edit: instant downvote instead of counterarguments. Energy storage is still pretty expensive regardless of the # of votes (positive or negative) that this comment attracts.
The actual statement was that the "EEG Umlage" (=surcharge on the electricity bill) would cost about that much in 2004. And that was perfectly true.
Furthermore, renewable generation varies a lot by region. Solar's cost per watt is way different in California or Hawaii than it is in Massachusetts. This is both in terms of less sunlight (inclination of the Earth, plus weather) but also land costs. This could be ameliorated by long-distance transmission, but that has its own problems even within small states [1]. And we'd have to increase the net-cost of deployments to match.
There's none of these asterisks and hand-waving with nuclear. Heat water, spin a turbine. Energy where you want it, when you want it.
1. https://www.vox.com/videos/22685707/climate-change-clean-ene...
Storage cost is falling even faster than solar or wind ever did. Some storage pilot projects have been abandoned as alternatives undercut them, as happened to concentrated-solar when fixed-PV cost fell below the cost of tracking mirrors.
But you have already had this explained to you, several times over. Pretending not to know about it is not a good look.
The plan for renewables is to build until saturation is reached, then burn gas while we cross our fingers and hope that an invention makes storage effectively free.
Also: the Paris accords are for net-zero. That means no more carbon emissions than carbon reclaimed and sequestered. (Carbon reclaimed and then burnt again does not count.)
Actually removing carbon dioxide from the atmosphere is the stuff of scientists and PR moves. Nobody has a serious plan to remove carbon dioxide from the atmosphere at relevant scales. The only example I can find would capture only 900 tons of CO2 per year.
We'd need to build 4 nuclear plants for each one that exists in the US to have a 100% nuclear electrical grid. It's something that we've done before, we would reach this goal early if we built plants at the same place we did in the 1960s and 1970s. This doesn't rely on a moonshot succeeding.
Renewables rely on a storage breakthrough or a sequestration breakthrough (but if we have the latter we could just keep using fossil fuels anyway). Relying on any kind of breakthrough yielding a 1,000x improvement is very reckless. You can insist until your lips turn blue that we just need to some type of electrolysis invention of another breakthrough of thermal storage and it's surely right around the corner. But until storage or sequestration is on the market, there's no real plan just hope that some breakthrough will happen.
1. https://www.climatecentral.org/news/first-commercial-co2-cap...
No "breakthroughs" are needed for storage. Everything works already. All that is unknown is which will end up cheapest.
But you already knew all of this.
Again, no, if nuclear power plant construction was carried out at the same rate as it was in the 1960s and 70s it'd be completed on time. You might be doubtful that we'd be able to manage that pace of construction in the 21st century, but at least there's precedence for that pace of construction actually being achieved.
> Just the money spent on coal, in the meantime, not counting nuke construction, would be more than the cost of building out enough renewables.
That's a very bold, source-less, claim you're making. Unfortunately the numbers don't even remotely add up. At a total of 535 million tons, and 36.14 dollars per ton for electric power consumption, we're looking at only $20 billion dollars of coal sales [1]. And that's generously assuming that all coal production went to electricity. If you're including power plant construction, that figure doesn't change much [2]. It's so small it's hard to see on the graph, but it appears to be below $25 billion dollars [3].
> No "breakthroughs" are needed for storage. Everything works already. All that is unknown is which will end up cheapest.
Right. We know something will make storage incredibly cheap. We don't know what kind of storage it will be. We don't have examples of it being delivered at that cost. But we just know it in our heart that something will save us and make intermittency a non-issue.
This is called "hope" and it's not a plan. The plan is to keep burning natural gas while wind and solar aren't producing, and keep our fingers crossed that our miraculous something will come about.
1. https://www.eia.gov/coal/annual/
2. https://www.eia.gov/todayinenergy/detail.php?id=45076
3. https://www.eia.gov/todayinenergy/images/2020.09.10/chart2.s...
We don't need "something" to make storage cheap. Storage is cheap, and is getting cheaper.
Again, we are not building storage out yet because we don't have enough renewables to charge it from yet. Instead, we are right now building out factories to make it. E.g., the factories to make iron-air batteries, $20/kWh, are under construction right now. Ammonia synthesis plants are under construction right now. Tankage for ammonia is dirt cheap. No breakthroughs needed, just build-out.
When we do get to building out storage itself, it will be cheaper than it already is.
All we know is that France has cheap electricity (nuclear) and Germany majestically fucked up by shutting down nuclear, wanting to build renewables, and in turn ended up addicted to Russian carbon drugs.
Germany was always dependent on fossil fuels. They have been adding wind turbines at a breakneck pace, getting incrementally less dependent. Fixing those ramshackle old contraptions would have cost much more per unit power out. They have already built out more wind generating capacity (averaged) than the reactors shut down produced. Germans, anyway, know this.
France is not building new nukes, nor even patching up old ones, because it is extremely expensive, and not getting any cheaper.
When people have to lie to try to make nukes look good, what are they really telling us?
False! https://www.france24.com/en/europe/20220210-announcing-new-r...
More the fools them.
Ships with reactors will not work. That will turn into a paperwork nightmare in every harbor it enters.
The conversion will be accelerated by restrictions on docking bunker-oil burners.
At least with a traditional water-cooled reactor there's very thick walls for the seawater to corrode through, and then the fuel itself is in a relatively inert oxide form. Similarly for a lead-cooled reactor, when the ship sinks the lead would solidify creating a big radiation protection armor around the fuel elements.
Pumped hydro, cryogenic storage, thermal storage, batteries, green hydrogen etc may tackle a lot of that but we simply don’t know what solution will end of working best.
Wind and solar has to be primary focus for the next 10-15 years but once we reach 60-70% of the grid being renewable you cannot really go much further. Solutions which can deliver power on demand will be crucial. If MSR guys can get stuff going within 10 years then they may be part of the solution.
There is no place for nukes in the inner solar system. Out Jupiter and beyond, ok.
We're already dipping into times of negative electric power cost in places with high renewable penetration... and a whole lot of the rest of the day where storage is needed, and a whole lot of usages that are not electric yet which will increase demand.
Yes, more renewable build out is necessary and helpful. But it won't get us low enough in carbon intensity soon enough alone.
It's not like there's one purely fungible pool of resources to build all things and solve all human problems.
Diversity in approaches is way better than your all-eggs-in-one-basket strategy.
Since each dollar spent on renewables produces several times the watt-hours produced by a dollar's worth of the nuke, diverting that dollar to the nuke has brought climate catastrophe that much nearer.
Money is fungible, but the individual supply curves of different things you buy with the money aren't flat.
> and is not cancelled after years of delays and cost overruns
This is a super-disingenuous argument, especially since I'm guessing you're part of a faction behind the scene inducing many of these delays, cancellations, and cost overruns through objection to nuclear's safety and utility.
> Since each dollar spent on renewables produces several times the watt-hours produced by a dollar's worth of the nuke, diverting that dollar to the nuke has brought climate catastrophe that much nearer.
Alternatively, every year assuming that renewables will eventually be able to provide enough industrial and base load through storage, if in error, commits us more and more to climate catastrophe. You handwave away objections. Storing enough is going to be really really hard and may not happen in time.
Our extant example of a very-low-carbon grid has a big mix of nuclear in it. We may not want to commit to building the exact same thing, but I don't think we should totally ignore the example that has produced this outcome.
Once one of these multi-$billion projects gets started, nobody involved wants them ever finished, because that is when the gravy train stops. So long as people are willing to pony up for overruns, they are happy to provide them.
That is why modular nukes never got legs: there is insufficient scope for graft.
The Finns finally had to finish their thing when it looked like the money would dry up either way. It will be interesting to see whether the French drag out theirs.