U.S. Nuclear Power Plants Weren’t Built for Climate Change
bloomberg.com
bloomberg.com
What if it is not profitable any more? Who would deal with the mess? Of course, public! Bit if it public who owns the risk, why is the "good part" owned by some private interest?
The main cost of a nuclear plant is the initial construction. Once you've paid that as a sunk cost, the cost of continued operation is tough to beat. There is a reason the older reactors operate for so long and it's not because continuing to operate them isn't cost competitive.
> Who would deal with the mess?
Nuclear plants are required to put money into a decommissioning fund for this. (Notably nothing else requires this. Who pays to deal with recycling old solar panels? Coal mines? Hydro dams?)
> Bit if it public who owns the risk, why is the "good part" owned by some private interest?
Because they supplied the money to build the plant.
Now that we actually start decomissioning them in Germany it turns out that decomissioning nuclear plants is more expensive than constructing them. Everything has to be measured for radioactivity, with a significant portion of the structure turning into nuclear waste due to being exposed to radioactivity for decades.
Insuring nuclear plants at a fair rate would also be really expensive. While serious accidents are rare they are exceedingly costly. The Fukushima disaster cost somewhere around $100-200 billion. Ukraine still spends 5-7% of their national budget on Chernobyl, 30 years after the disaster. Somewhat strangely most of that financial risk is taken by the government instead of the plant operator.
They turned off every security check to test what would happen.
Doesn't seem very smart to me.
If I had to pick one reason, I would blame reactor design. The RBMK reactor had what’s known as a positive void coefficient. When voids (boiling water pockets) formed, these reduced the reactor’s ability to moderate neutrons, thus accelerating the reaction rate. This makes the reactor fundamentally unsafe, and guaranteed that something was going to go wrong.
This is a design flaw that has thankfully been fixed in other reactors, including all other RBMK reactors. The flaw was known to the Soviet’s at the time, but the RBMK was designed to produce nuclear weapons, so they swept the flaws under the rug.
Actually, what the loss of water did was reduce capture of neutrons on hydrogen. The moderator, graphite, remained in place and was more effective.
But human error happens and has to be in your risk calculation. Just like natural disasters happen (Fukushima was insured, just not against earthquakes, tsunamis and the like)
Edit: for context, "unusually expensive" means we hope to get the whole thing fixed within the 21st century.
Edit: typo
I'll admit to not speaking German, but wasn't a contributing factor that the government simply didn't give them very much notice they were being shut down?
I've worked on mine sites at an industrial scale that couldn't hope to remediate the pit if they were hit with a short-term shutdown - it'd be an ecological and social disaster. However, if you let them run to planned completion the remediation gets done.
like ten to twenty years? The nuclear exit was agreed on in 2000 and they were given long times to close their reactors.
When should a company start saving for a shutdown? In the last days?
My impression was it was a little more political and complicated than that [0]. I mean, if it was technically time to shut down the reactors then somebody obviously screwed up - but Germany isn't a great place to be citing examples from because their government has obviously been a massive headache for anyone planning out a nuclear reactor's lifespan.
> When should a company start saving for a shutdown? In the last days?
It should start when it needs to to have budget + contingency at the time of shut down.
[0] https://www.world-nuclear.org/information-library/country-pr...
Really? Worse than anyone else? Looking at the map on Wikipedia, there don’t seem to have been any reactors in East Germany, at least not at the time Fukushima made nuclear a dirty word again, and the post-cold-war political shifts was the only unusual stability issue I could think of.
In 2000 the phase-out was decided (the negotiations between the companies and the government started in 1998). The nuclear companies didn't do anything to prepare for it, but instead hoped that a government lead by the CDU (conservatives) would cancel it. In 2009 with a government formed between CDU and FDP (market liberals) they got their wish and it seemed their lack of preparing worked. Unfortunately for them in 2011 Fukushima happened and even the CDU couldn't just ignore anymore that the citizens don't like nuclear power very much (They lost Baden-Württemberg to the Greens shortly after, something unthinkable a few years before that) and reinstated the phase-out.
So, no, it's really not more complicated than that. From 2000 on the writing was on the wall and instead of preparing for it the companies just sat on their hands and hoped for the best.
> Unfortunately for them in 2011 Fukushima
So if they had been diligently saving until 2009, then cleared out their financial buffer in 2010, they would quite reasonably be caught flat-footed in 2011?
What is being described here is a problem, but it is not a technical problem and it is iffy to blame corporate wrongdoing. I've literally done rehab planning; these are short time frames and are clearly being driven by politics not technical planning.
Decommissioning isn't something that gets done for fun. Companies need time. It seems completely reasonable that they borrowed the money to decommissioning rather than having it on hand.
If - sure. And if they hadn't lobbied the CDU/FDP for years to take it back it probably wouldn't have happened. Many ifs. But they didn't save up and they did lobby both parties.
Not really. The shutdown plan was done in 2000 together with the industry. They knew what would happen. But the industry did not believe that this will happen, because they thought there was still enough political support for nuclear power and once the opposition (the conservatives) will be back in power, the nuclear exit would be reversed.
That exactly happened then: The conservatives reversed the exit even though there was much ongoing public protest and the nuclear industry was happy.
Then Fukushima happened and conservatives basically went back to the nuclear exit, because they feared widespread public protests. Merkel was clever: if one can't win, then join the other side.
The oldest and most problematic reactors were closed very fast then. But it was already clear in 2000 that they eventually would go offline before the rest. A few reactors even did not need to be closed, they happened to be already shutdown temporarily because of various problems and regulators then just refused them to be activated again. Example: AKW Krümmel near Hamburg.
Problem: I would not believe that a profit oriented company without being forced puts billions aside for a clean-up. I would also not believe that the money put aside is actually sufficient - given that many costs are probably not calculated into it. Every commercial company will try everything to calculate future costs then as low as possible. Especially multi-billion Euro/Dollar sized monopolists which are a save haven for former politicians.
I randomly picked a German utility involved in nuclear; RWE has annual revenues of $40-50 billion [0].
You can rest easy; they have the ability to come up with the money if governments want to insist. You just might need to give them 5-10 years rather than surprising them if you want it to happen economically.
> You just might need to give them 5-10 years rather than surprising them if you want it to happen economically.
Nobody surprised them. Timelines were long known and RWE negotiated all that.
the main cost is storing the waste for 10k+ years with zero defect rate
Even equipment used to decommission a nuclear reactor becomes contaminated. It’s not that dangerous for very long, but safe disposal is still expensive.
From a pro nuclear website: 97% of the waste produced is classified as low- or intermediate-level waste (LLW or ILW). Such waste has been widely disposed of in near-surface repositories for many years. In France, where fuel is reprocessed, just 0.2% of all radioactive waste by volume is classified as high-level waste (HLW) http://www.world-nuclear.org/information-library/nuclear-fue...
For example: https://en.m.wikipedia.org/wiki/Yucca_Mountain_nuclear_waste...
So if you don't like the nuclear waste we already have, build newer reactors to get rid of it.
We are now getting China and France to build our new nuclear, having successfully driven our own industry into the ground by lying to our customers.
edit - what worries me about nuclear power is the attitude and practices of the industry, not the technology per-se. The only group I have ever heard of that comes up to scratch for how you would want nuclear plants to be run is the US Navy, though that might be because they live on them.
(Technically an exception is the bn-800 but it was modified rebuild from an 80s aborted reactor construction project, to get rid of weapons grade plutonium, before the the us/russia treaty fell apart... Good story at http://euanmearns.com/the-bn-800-fast-reactor-a-milestone-on... )
Not really, what happened is there were "good enough" designs, there was a China Syndrome inspired move away from nuclear, and the government had little to no interest in reactor designs that made it hard to recover weapon materials.
Bill Gates is championing both molten salt and traveling wave reactors that "burn" nuclear waste.
There are other very interesting designs, including the Xscale helium-cooled pebble bed design. It, and many of the molten salt designs, don't require water cooling. Not needing a source of nearby water vastly expands siting options.
https://www.energy.gov/ne/articles/x-energy-developing-pebbl...
Another interesting design is ThorCon's molten salt reactor, which it recommends siting 100 feet underground, eliminating almost all security issues including plane strike.
The subsidies have been in the form of the MOX program, PRISM, and other gov funded fuel recycling programs in many countries. The problems remain: weapons grade Pu profileration risk, unviable cost, dearth of demonstrated working large plants due to technical difficulties inherent in the designs, difficulties scaling up to commercial sizes competitive w traditional designs.
Yes, there are many interesting designs on the drawing table, same as it has been for decades...
"In December 2016 the government estimated decontamination, compensation, decommissioning, and radioactive waste storage costs at 21.5 trillion yen ($187 billion), nearly double the 2013 estimate." [1]
For comparison purposes, Diablo Canyon cost $13.8B to construct in 2018 dollars. [2] That same page states graceful decommissioning of the plant is estimated to cost $4B (!) dollars.
[1] https://en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disa...
That is poetic justice, given that the Japanese government could have made sure the backup generators were stored securely. They were, as it turned out, fairly important. ;-)
Don't forget that a couple of working diesel generators providing power to keep the cooling working would have entirely avoided the disaster. Some were actually flown there in time, but the connectors were wrong and time ran out.
> This money could have been spent on 50GW of wind capacity instead.
Sure, and when the wind doesn't blow, and the storage runs out, and it's a nighttime cold event - people freeze to death. That's aside from the economic effects on industry from unreliable energy sources.
Wind costs generally aren't being calculated correctly, as reliable backup power is required for any wind that dips into the "minimum baseline" power supply, which is the essential power required for basic needs and industry.
Nuclear is overall one of the safest ways of producing energy, and is the ONLY scalable, reliable power source that doesn't emit CO2. With mass-produced, modular, reactors, it can also be the cheapest power source overall. Cheaper than wind, solar or coal.
The world desperately needs mass nuclear power from a couple of perspectives. If Global Warming is in fact a major threat, there is no choice in the matter. That is my touchstone as to whether or not the "Green" movement has gotten serious about it.
This is an example of pro-nuclear ignorance. Renewables scale just fine, and are sufficiently reliable with a properly designed energy system. Their huge levelized cost advantage over nuclear means one can afford to mitigate their intermittency with overcapacity, transmission, storage (short and long term) and demand dispatch.
An average 3 MW wind turbine will generate about 6 GWh of energy per year. It's estimated that wind farms can produce around 4 MW per square kilometer, so let's go with around 8 GWh per sqkm.
In 2014 the UK used about 302 TWh of electricity (out of a total energy usage of 2249 TWh). To match the 302 TWh of electricity with these wind turbines you'd need wind farms covering 37,750 square kilometers. To cover the UK's total energy usage, you'd need an area greater than the surface area of the UK to be covered in wind farms.
These are back of the envelope calculations, but they do point out the problem rather well.
Europe in general will have trouble in a solar-powered future, though. Energy intensive industry will migrate to the cheap energy closer to the equator.
* that would mean 17.5MW/sq km. So yes, better than GP figure. No, still not usable (improvement of only factor 4.5).
EDIT: Quick calculation based on numbers here: https://en.m.wikipedia.org/wiki/Solar_power_in_Germany#/medi... gives me solar utilization factor of 9.5 for Germany in 2016.
Also lots of wind parks are off shore where there’s less vegetation and hills to slow down wind.
And 2249 TWh / 8 GWh = 281,125
>Also lots of wind parks are off shore where there’s less vegetation and hills to slow down wind.
They're more expensive to construct and tear down after. They do generate more power, on average, but in these calculations with average it would only give you a ~20% advantage.
None of these are Gen IV reactors, thought the last two are labelled as gen III+, which looks like the kind of labelling a hopeful chipmaker might slap on a processor when they add some bells and whistles to an existing design. Do you know where any gen IV reactors are being built currently? I hear a lot about them, but they seem mostly to be vapourware.
Also, Hinkley C, which is currently under construction, has a strike price so high it will probably be mothballed as soon as it is finished, with an analysis by London stockbrokers Liberum Capital describing it as 'the most expensive conventional power station in the world' and 'economically insane'.
This is the new nuclear actually being built. If there is better, safer, cheaper available in gen IV reactors, why is that not under construction instead? If they are available, the UK government will presumably also know about these reactors, yet it is apparently not interested in building them.
At this point, I will believe a new generation of reactors is cheap and wonderful only after N of them have been built, costs have not exploded, and the maker isn't in bankruptcy.
The implication that stupid people are the ones lobbying against nuclear is deplorable. I'd argue the shoe is on the other foot. Nuclear's cost disease renders continued pursuit of the technology very difficult to justify.
Most often it's ignorance and not stupidity.
> I'd argue the shoe is on the other foot. Nuclear's cost disease renders continued pursuit of the technology very difficult to justify.
Nuclear's "cost disease" is a function of an industry that, for one thing, functions a lot like the dinosaur space launch companies (ULA). Somehow SpaceX came along and completely disrupted things.
The small, agile companies pursuing small modular nuclear reactors are a lot like SpaceX. Probably the most disruptive idea is that of building the reactors at factories, and then transporting and installing them with little additional work. That avoids the entire red tape and risk of one-off construction, and affords economies of scale.
Since there's a very effective and strident anti-nuclear lobby here in the US, these companies will get started elsewhere. Keep an eye on ThorCon, X-Energy, Terrapower, and NuScale.
> According to IAEA, there are 50 designs or concepts in various development or planning stages around the world, with four in advanced construction in Argentina, Russia, and China.
https://www.scottmadden.com/reports/V17_I2/EIU_V17_I2_2017_D...
SpaceX operates by testing a lot and blowing things up. You're not getting that with nuclear. The SMR makers have not delivered much; the closest to delivery, NuScale, is not giving cost improvements that will be sufficient to turn nuclear's ebbing tide.
The levelized cost of solar and wind are well below that of new nuclear. If you did not know this, well, you were ignorant.
> That looks like a pretty big incentive.
Funny you should compare natural gas and nuclear. Exelon, which operates 23 nuclear reactors in the US, did the same thing. The conclusion Exelon came to was that new nuclear construction is hopelessly uncompetitive with natural gas fired combined cycle in the US at current natural gas prices. An effective CO2 tax of $300-400/ton would be needed for new nuclear to compete.
Yes, nuclear saves on fuel costs, but it's a penny wise, pound foolish saving.
> SpaceX has an exemplerary safety record. More misinformation...
SpaceX blows up plenty of stuff IN DEVELOPMENT. They just blew up their manned capsule during ground tests, for example. Applying the same development methodology to nuclear would be a nonstarter. In nuclear you need to avoid accidents everywhere. Paralysis by analysis follows.
> ThorCon is estimating to-the-plug electricty costs of three to five cents per KWH.
Uh huh. That estimate, and $5, will get you a cup of caffeinated brown water at Starbucks.
And what "facts" would those be, exactly...?
Let's start with the incentive to mess with nuclear at all, beginning with the cost of fuel.
>> A modern American light-water reactor has a fuel burnup in the neighborhood of 45 GWd / MTU (45 billion watt-days per metric ton uranium).
So, a metric ton of uranium produces 4.5 billion Watt-days, or 108 GWH.
By contrast, a metric ton of natural gas produces 15.2 million Watt-hours, or 0.0152 GWH.
That means a ton of uranium produces 7,105 times the energy of a ton of natural gas. A ton of uranium costs about $1,400. A ton of natural gas costs about $150. That means the natural gas equivalent of a ton of uranium would cost $150 x 7,105, or about $1,070,000.
That looks like a pretty big incentive. The other is the zero CO2 issue, with nuclear being the only, sole, solitary, single, scalable, existing reliable source of zero CO2 energy. I hope I don't need to explain why that's relevant.
> SpaceX operates by testing a lot and blowing things up.
SpaceX has an exemplerary safety record. More misinformation...
> You're not getting that with nuclear. The SMR makers have not delivered much; the closest to delivery, NuScale, is not giving cost improvements that will be sufficient to turn nuclear's ebbing tide.
ThorCon is estimating to-the-plug electricty costs of three to five cents per KWH. That's vastly cheaper than any "green" electricity source, and better than any alternative in most locations.
Nuclear done sanely is at least competitive with fossil fuels, and is the only scalable, reliable source of zero-CO2 electricity. Having enough grid storage to (usually) make it through low output periods for wind and solar is nothing beyond wildest fantasy at this point.
Nuclear power is a necessity if a very low CO2 trajectory is required.
2) The energy density of uranium is admittedly spectacular. If you compare only uranium prices and fossil fuel prices, uranium wins every time. The problem is that all the equipment and personnel to turn uranium into electricity end up making American uranium-fueled electricity more expensive than gas-fueled electricity. That's why cheap gas has pushed so many operating American nuclear plants into the red, and why those plants need support beyond market prices to keep producing their steady low-emissions electricity. Quoting uranium price alone for nuclear power is like quoting silicon price alone for solar power -- it has very little bearing on the final delivered price of electricity.
3) Practically every power reactor design claims to supply affordable electricity before anyone actually builds one. The EPR did. The AP1000 did. Like pfdietz I'll trust ThorCon's claims after they have operating reactors to prove it, not before. New reactor designs claiming big improvements are no more special than big claims about spectacular new batteries or solar cells. Wait for commercial delivery, then measure. Most of these exciting early claims go nowhere.
So the catch 22 then. Don't build newer reactors until you prove something that requires building them to prove.
> Nuclear's cost disease renders continued pursuit of the technology very difficult to justify.
Why isn't the solution analyzing where the money is going so that the wasteful expenses can be eliminated then?
(Note that one of the major ones is regulatory requirements changing during construction, which is an entirely politically-driven cost.)
> Why isn't the solution analyzing where the money is going so that the wasteful expenses can be eliminated then?
Why do you think that hasn't been tried?
You seem to have the preconception that there must be some way for nuclear to live up to your expectations for it, despite all the evidence that it can't and won't.
There are plenty of reasons to be optimistic that the Earth's natural nuclear fuel resources can find a way to be effectively used by humanity. We've done an OK job at it so far. It's relatively safe. It's very low-carbon, and it has been making ~60% of the USA's carbon free energy for a few decades. Not a bad track record.
But it's a bit too expensive. So we just have to figure out ways to make it cheaper.
This certainly doesn't seem insurmountable. I don't think a "can't and won't" curse is at all warranted.
I think nuclear energy optimism is largely based on wishful thinking.
Meanwhile nuclear plants go on saving millions of lives by displacing air pollution deaths. China is building high-power district heater reactors to reduce coal deaths in Winter [1].
You're absolutely right that rapid improvement requires high volume. That's probably the fundamental challenge of nuclear right now. MIT is working on shipyard constructed nuclear stuff that has these characteristics for this precise reason [2]. UltraSafe nuclear's microreactors are attempting the same dynamic [3].
Human progress depends wholly on people taking bets like this.
[1] https://www.reuters.com/article/us-china-nuclear-heating/chi...
[2] http://news.mit.edu/2015/new-look-floating-nuclear-power-062...
https://blogs.platts.com/2016/03/29/nuclear-safety-upgrades-...
"Power companies in Japan are willing to spend billions of dollars on reactor upgrades because they expect the investments will help them reduce substantial costs spent on replacement fossil fuels. Restarting the two Takahama reactors, for example, could save about Yen 10 billion/month for Kansai Electric Power Co., a company spokesman said March 22."
For specifically this, at least for consumer purchases I think it'd be somewhat covered by the WEEE directives in the EU. The manufacturer and distributor should be either providing or paying for the recycling.
Common in the oil industry: https://www.google.com/search?hl=en&q=oil%20field%20cleanup%...
So the answer to it potentially being the public's problem is to guarantee that it is the public's problem? That isn't necessarily a bad idea, but it doesn't gel with how the rest of the economy works.
What you mean to say is "Make the public responsible and accountable for something the private sector will try to weasel their way out of."
Which is perfectly acceptable.
Also, people aren't idiots. If something sounds insane it's probably because you don't understand the situation and incentives well enough, not because it's actually insane.
Well... 50-60 year old designs can't exist without electricity to the pumps.
[1] https://en.wikipedia.org/wiki/Experimental_Breeder_Reactor_I...
But that didn't happen, and, absent uranium shortages, breeder reactors are more expensive than ordinary thermal reactors. There's also the small problem of fast breeders being potentially subject to prompt fast supercriticality during a meltdown. That's one of the few ways to make an accident worse than Chernobyl.
This is a problem for a lot of power plants, although most non-nuclear ones can safely survive a sudden shutdown. Starting up after a total shutdown is known as "black start" and an important part of contingency planning: https://www.drax.com/technology/black-start-important-back-p...
I'd be super interested to read it.
There are a range of renewable generation and storage options only seriously industrially developed for just a couple of decades yet already wind and solar products are the cheapest form of new generation (without subsidies).
So in depth comparative analysis is moot now, current renewable options are cheaper even including current storage options to make them dispatch-able, and they will continue to get cheaper. Nuclear will not catch up without some game changing invention which would practically amount to a new technology that we cant debate yet.
Only lingering passionate argument from the years when there was some uncertainty about renewables potential maintains any vision of nuclear competing with them to provide carbon neutral and environmentally friendly power, at the present and into the foreseeable future.
https://www.lazard.com/perspective/levelized-cost-of-energy-...
Most people agree with the consensus that nuclear and some renewables (wind/solar/hydro) are low carbon. Other renewables (biomass) are not low carbon.
Then we quickly descend into a debate that effectively comes down to energy storage for the intermittent renewables vs. the cost of nuclear. Wind is at full power ~35% of the time in the US, solar is at full power ~25% of the time in the US. Recent nuclear builds in the US and Europe have been absolute boondoggles, though S. Korea remembers what the learned from Combustion Engineering and can build standard reactors very well now.
Energy storage discussions span daily fluctuations (e.g. the duck curve) and batteries to seasonal fluctuations (much more challenging for know storage tech).
Nuclear discussions also inevitability dip into nuclear waste (which has a scientific consensus solution in the deep geologic repository) to safety (where more people die every day from coal as-normal emissions than have been killed by nuclear accidents ever). Renewable discussions dip into land use, San Bernardino Co's recent ban on new large solar in the desert, migratory Hoary bats getting their lungs ripped out by wind turbines, and so on.
I consider nuclear a total underdog right now because Wind and Solar are kicking butt while nuclear plants are getting shut down early. Because of this dynamic, I advocate for nuclear as part of the low carbon future. I wrote a thing about these topics in more detail here [1].
Bill Gates recently said that the people who say solving climate change will be easy are now more of a problem than people who outright deny climate change [2]. I agree with him. Lots of headlines you see on /r/Futurology and /r/energy make it seem that decarbonized world is right ahead of us. It's not, and cheap fracked natural gas is enemy number one. Sure, it's half the CO2 of coal, but that's still an order of magnitude too high!
Many pro-nuclear people like myself are also very pro low-carbon renewables. The one vs. the other mentality is strong in both camps, but there's a growing number of "centrists".
[1] https://whatisnuclear.com/blog/2017-12-17-primer-on-energy-g...
The lesson from recent nuclear power plants in Europe is that we can't build them on budget and on time anymore. Maybe nuclear is affordable if it's on budget, but is it still when there's massive budget overruns?
How does the cost trend look? It doesn't seem likely that we'll be able to relax regulations on nuclear.. so is it likely to get significantly cheaper? If you look at cost projections 20 years into the future, will it still beat solar- and wind with storage?
And are there developments in load following nuclear power plants? Solar and wind needs to be paired with load following plants, not base load.
It seems to me like we need to put massive investments in R&D to develop a small plant (so it's easier to iterate) that can be a perfect match with solar/wind, yields less dangerous waste and has low proliferation risk..
I've seen some interesting startups in this area. Everyone working on it should be given more money and regulatory support. I feel like there's a significant risk that those developments could be made irrelevant if there's further breakthroughs in renewables and storage, but we need to hedge our bets.
Nuclear in the West is in rough shape, but again the Chinese, Russians, Koreans, and even the Japanese are pretty good at popping them out on time/budget. They all have established supply chains and trained craftsmen. Korea, in particular, is amazing. They chose one design and standardized it and built a bunch of them. This is the model of success in nuclear.
For this reason, it worries me a bit that lots of small startup in the US are trying to build different reactors in relative isolation. This is not the kind of industry where that is likely to go well. It takes billions of dollars to get to first product.
I think the open source model is much more likely to succeed in nuclear. Most of the tech is commodity anyway, so finding a business plan around this shouldn't be overly challenging.
The guy who built Korea's nuclear industry just did a great interview where he basically said that the US taught him how to build nukes, they perfected it, and now he wants to partner with the US again to decarbonize effectively with standardized nukes. [1]
https://www.technologyreview.com/s/613325/how-greed-and-corr...
I often wonder about non-compact kinetic energy storage, like huge fly-wheels or railcars, since kinetic energy is quadratic with velocity. When using a large radius circular railway, the limiting factor is no longer tensile strength as in usual fly-wheels. I wonder how low frictional terms can be brought for evacuated tunnels. the rail could be the stator and the circular train the rotor, or the other way around: a constant cross section "train" of mass with a rail as the rotor, and the fixed train wheels as the stator underneath... if it is underground or in a pit accidental energy release could be less catastrophic.
https://www.osti.gov/biblio/6836648
https://www.researchgate.net/publication/224376883_Magnetica...
Then ponder the financing problems of decades long megaprojects counting on a certain minimum electricity price after completion.
People often think of Thorium reactors in the molten salt configuration (i.e. the Thorium-MSR), which should be very safe. The Thorium gets conflated with the molten salt, but there are uranium MSRs too which are just as safe.
It's harder to turn Thorium into nuclear weapons, so a nuclear state could provide fuel to a non-nuclear state. Thorium is more abundant and easier to mine. There's much less nuclear waste from a Thorium plant and it decays to safe levels of radiation in a few hundred years making safe storage easier.
"Not only can they technically (but with much difficulty!) be used to make bombs.... It may be difficult to do this several times without going subcritical, but it certainly could be done"
So yeah, it's technically possible to make a bomb with byproducts from a Thorium reactor, but it's not trivial.
"Considering that the oceans contain 1.4x1021 kg of water, that amounts to 56,000 tonnes of Th and 4.62 billion tonnes of Uranium. Moreover, mining the entire crust is difficult, whereas the ocean delivers to you. While seawater extraction of uranium is not yet competitive with traditional mining (it’s hovering around 4x more expensive), it is possible and may become economical in the near future"
Pointing to a source that's not feasible and use some handwavy "Well it might be done in the future" doesn't really disprove the point that Thorium is more abundant in the places we can actually extract it from.
"In fact, the long-term decay heat from Thorium-MSRs can be orders of magnitude lower than that from traditional reactors"
On this point the article agrees.
It's not trivial to make a nuclear bomb period.
Thorium is attractive because it's widespread and lower cost and supposedly doesn't have as many proliferation issues as LEU, since its fuel cycle also creates U232 along with fissile U233. U232 is highly gamma radioactive and thus quite difficult to separate from U233. OTOTH U232 would keep being radioactive for at least 700 years (10 half lives), so we woldn't want any U232 contamination occuring.
SMRs are getting attention now only because big reactors are essentially dead commercially. So I propose they be renamed HMRs: Hail Mary Reactors. They are the last shot nuclear has, and not a very good one.
For what is your factor of 70?
100% renewable would require something like 10000 gigafactories to make batteries, probably not sensible. 50% means we don't need trillions of batteries.
that's assuming everyone moves to only use 2kW of energy, instead of 6 for North America and 4 for Europe. Hopefully switching to electricity will account for most of those savings.