I have been doing my best to find critical information on the viability of Thorium based nuclear reactors (because they sound too good to be true).
Everyone sings their praises, but what engineering challenges are there and are those engineering challenges large enough to discourage their development/adoption?
The biggest thing I have found is that the salt solution for Thorium reactors is quite corrosive and that is challenging to contain.
It generally sounds really promising - even the Wiki page for thorium MSR sings its praises.
Why wouldn't it work? Why isn't the world throwing shit-loads of money at this? Is China enlightened or is this some kind of meme-ware technology they fell for (or are trying to convince others to waste their money on)?
Good write up from a great guy. IIRC the author of that page, Nick Touran, works (worked?) for one of the Nuclear Startups that Gates funded. Met him and had a few drinks once, guy knows his stuff.
Hm, reading that, it doesn't seem to disprove or actually illuminate that much IMO:
Misconception #1: I assume this is listed first because it is the biggest reason Thorium reactors weren't pursued? But really most MSR people seem to view it as political, and the bullet points in "Misconception #1" only underline that.
Misconception #2: Almost all MSR presentations seem to assume a fissile "ignition" supply of uranium, that isn't hidden. And it seems to dovetail with the political opposition, since the regulatory agencies will block the supply of fissile uranium to start an MSR with. So this point seems to again highlight artificial/bureaucratic blockades.
Miconception #3: Well, ok, this seems to be a decent answer based on the fundamentals of the science and engineering.
Misconception #4: This seems to ignore the fact that a very very small amount of uranium is naturally fissile, while the Thorium all breeds to fissile. It also spouts off about seawater extraction, which hasn't happened AFAIK. This answer seems very misleading.
Plus, the fact the author is from a competing design (a pebble design I believe, and one of the reasons pebble designs seem to exist is because of the prohibition on research labs from booting up a liquid reactor).
I do agree the unknowns are the vessel degradation from the salts, but materials engineers these days are just so amazingly good.
It just seems frustrating that the overarching influence of regulatory agency stubbornness and lobbying influence of solid fuel rod reprocessors and other fuel makers (who have a monopoly on nuclear fuel production I believe due to the regulatory agencies) is evident in this article.
If it is true that China gets breeder/thorium/liquid reactors going, it all doesn't matter. The US will be a decade behind, and with the anti-nuclear opinions of the US voting populace, that will afford the entrenched interests cover to keep suppressing nuclear.
I suppose it doesn't matter right now. Solar/Wind/Battery is improving so quickly you can't forecast/target a price/budget for a reactor design that is invariably 5-10 years out.
Has anyone seen AcidBurn recently? They've been notably absent for some time. They used to appear in essentially any HN forum with nuclear. I miss their expert insight.
Note page 23! Almost all the 137Cs ends up outside of the core, due to sparging of precursors. "Over 40% of [fission products] leave core"
Lots of other issues, particularly with radiation damage and corrosion of reactor structural elements. Unlike in a solid fuel reactor, there is fission going on right at the boundary of the salt. In a LWR, there is a layer of water between the fuel and the reactor structure to provide shielding. There will be non-fuel components of a MSR that are not lifetime components, but will have to be swapped out due to degradation. Some MSR designs are proposing to just swap out the entire reactor vessel because of this.
> The biggest thing I have found is that the salt solution for Thorium reactors is quite corrosive and that is challenging to contain.
If you can figure out the molten salt problem you can replace the nuclear reactor with concentrated solar thermal and get solar baseload power without having to worry about meltdowns for way less than the cost of a nuke plant.
The salt in MSRs has different requirements from that in solar thermal systems, so there's not really a connection. Also, solar thermal is pretty much a dead technology now; PV (and batteries) killed it.
Existing energy industry is too entrenched in current technology to innovate? Widely publicized nuclear energy disasters prevents popular support? I don't know but this guy seems pretty smart
Nuclear reactors are complex beasts. Very complex. For example, here's [1] the webpage with NRC's safety evaluation documents for NuScale's small modular reactors. Dozens of documents, totaling more than one thousand pages. In many cases, there are years of work behind a single paragraph. Here's [2] an example where the NRC replies to some concerns raised by some advisory committee regarding some potential scenarios where the reactor may turn unsafe because of some boron technicality:
>>4.Operator recovery actions raise the possibility of an influx of deborated water into the core, which may result in recriticality, return to power, and the potential for core damage. Staff Response: In the staff’s SER for Chapter 19, dated July 17, 2020, (ADAMS Accession No. ML20196L734), the staff identified two post-event recovery scenarios that could pose a challenge to reactivity control. The first scenario is recovery from a non-LOCA extended decay heat removal system (DHRS) cooling condition which can occur following initiating events such as general transients and losses of off-site power. The second scenario is recovery from a LOCA ECCS cooling condition which can occur following initiating events such as breaks in the primary coolant lines. The staff notes that either action to inject would likely be governed by plant-specific procedures; however, such procedures are not required at the design certification stage and have not been developed. The staff evaluated the potential core damage risk for the two scenarios. For reasons discussed in the SER which are supported by two papers developed by the Office of Nuclear Regulatory Research (RES) (ADAMS Accession Nos. ML20191A069 and ML20205L317), the staff concludes that enough margin exists such that these recovery scenarios are unlikely to lead to core damage based on the physical effects of fluid mixing, reactivity feedback mechanisms, and associated time constants. Based on the SER and the two RES papers, the staff found that there is reasonable assurance that there are no known significant risk contributors that are unaccounted for and that the identified risk insights are acceptable to support the uses of probabilistic risk assessment (PRA) at the design stage.
My point is: there are plenty of corner cases, maybe thousands, and in many of these corner cases the outcome can be either a nuclear boom, or at least a Chernobyl or Fukushima scenario. They are low probability but high danger scenarios, so you need to spend a lot of time (and research money) to either rule out each corner case, or to develop foolproof mitigants.
When people say that this or that reactor design is inherently safe, they are talking about first order effects. When the NRC goes into all the details, things always get a bit more complex.
Edit: by the way, nuclear fission reactors can be supercritical (all current commercial ones), or subcritical (those need an external source of neutrons or protons, such as an accelerator). Only subcritical reactors [3] can be truly pasively safe. There are concepts of subcritical reactors that use Thorium as a fuel, but that's not what China is trying here. China is trying a classical Thorium reactor, where Thorium is used to breed fissile Uranium (not the classical U-235, but rather the isotopes U-232 and U-233), and that Uranium in turn proceeds to undergo the (supercritical) fission chain reaction.
Nuclear is far from the best source of electricity, but it is far less damaging to the environment than coal or NG if handled and designed properly. If countries can work together to put them in places that protect from major earthquakes or other natural disasters then I think we can get some decent movement on reduce GHG emissions from power plants.
> Nuclear is far from the best source of electricity
Just to be clear, this is a universal statement. The issue is that there are many factors to consider. There's cost, storage, total output, CO2 and waste production, physical footprint, environmental factors, local resources, and many other parameters that need to be considered when determining what _combination_ of energy sources should be used for an area. I believe that often people abstract these variables out and only concentrate on cost and a secondary factor that supports their point for the specific conversation. We should not be naive and recognize that these are extremely complex systems with equally complex solutions that require significant amounts of nuance to accurately discuss.
One nice thing about a molten salt reactor like China is building is that the dangerous fission products are chemically bound in the salt. If some external event breaks the reactor wide open, the salt cools and you just have radioactive rocks there on the site, instead of a radioactive cloud over a large region.
Look, I want to agree and I'm neither a geologist nor a nuclear scientist but I think you're fantasising if you think there will be no particulate, dispersed matter. The salt mix even if the lower temp melting mixtures is 200°C or more above ambient. It will explode on contact with moisture. There will be clouds of burning materials.
If you say LESS dispersed radiation? Sure. None... sorry not chemically or mechanically or hydraulically or meteorologically plausible.
The elephants foot degrades over time into dust. Radiation causes stress fractures in solids, crystalline structure disturbs. It's going to "decay" in the non radiative sense of the word.
Btw I am pro nuke, in Hypothesis. In my economy (oz) it would have been ideal 30 years ago. Now, with zero power nukes (only one medical manufacturer with a dido type swimming pool reactor) the build out is probably economically infeasible after lawsuit attack, compared to solar, wind and battery. But I remain hopeful of this new stuff, and the PBMR
There are plenty of volatile fission products in a molten salt reactor. For example, at MSRE, a large fraction of the iodine went completely missing and no one to this day knows where it went. Capable and redundant containment systems are absolutely necessary in these reactors.
If its design allows it to somehow avoid a BLEVE [0] from whatever fluid it uses to move energy from the reactor to the generator being suddenly liberated.
How long does it take to plan and build a nuclear plant? At the rate solar, wind and energy storage are improving, will it be worth the wait? Solar has dropped in price by more than 80% in the past 10 years.
Large reactors currently take at least 10 years to construct. The new small reactors are estimated to take at least 2-5 years.
These plants offer continuous power with minimal maintenance. Renewable equipment needs to be replaced and repaired at a higher frequency. They will also need storage and grid upgrades to stand as a direct replacement. They absolutely have a place in the energy profile. But, nuclear provides a type of base power that cannot be easily or cost efficiently accomplished by renewable technologies. We need to take advantage of the pros and mitigate the cons of each technology.
Compare the EROEI on solar (~10) vs nuclear (~100), and LFTR (~1200 maybe...) in particular, there is no comparison. In the future we will need far more electrical energy, it's not enough to just replace what we currently have. Also if we want to actively remove carbon from the atmosphere, we will need a tremendous amount of power.
Present-day reactors, a long time. Small modular reactors built in factories or shipyards could be pretty quick. Some of those designs are MSRs like China's reactor.
Fusion electricity is what will provide humanity with energy for centuries to come. It'll be available very soon and until then it does not really matter whether we will use nuclear or coal. We just need a final push for 50-100 years and energy issue will be solved once and forever. All the environment issues will be dealt with, when we will have a free energy and better technologies. Spending too much effort on cleaning environment now is not wise.
this also isn't the type of thing that governments tend to lie about. it's not like a scenario where a contractor overpromises and underdelivers and government media has to do damage control. they're also not announcing some new leap in scientific understanding. it's old science.
unfortunately the CCP has proven to us that we can't trust their word. Over and over again
Blaming others, deflection, and dishonesty is a common tactic used by every nation.
Remember when the blackout in 2003 was caused by Canada?
"Canadian officials insisted a massive blackout Thursday across the Northeast and parts of Canada originated in the United States, though U.S. power workers denied that and American officials blamed Canada."
Remember how the 9/11 terrorists also came from Canada? Canada doesn't control entry to the US, and they never came via Canada at all but this was often quoted in the media, as a deflection.
"Not one 9/11 terrorist entered the United States via Canada"
Reading the article, there aren’t huge scientific problems building these reactors. So, if there’s government support, it seems likely to me these will be built.
I also think China has proven that it is willing and able to rapidly build infrastructure. That makes me think their timeline can be in the right ballpark, too.
That’s something I would worry more about (disclaimer: China is huge, so it will have its share of disasters. It also probably will pay more attention to nuclear projects than to bread-and-butter concrete pouring for buildings and roads)
This guy on Twitter named Conrad Knauer [1] who has been diligently following satellite photos and cross-referencing them with the design publications for TMSR-1 that makes it all seem pretty believable. Pretty round-about way to verify things but it's something.
This moderator develops cracks during normal operation as seen in UK's AGR several other designs. And it burns in case of an accident (Windscale, Chernobyl). Since the TMSR-LF1 is an experimental project I also assume that it's a single fluid design? More detailed information on the TMSR-LF1 is quite hard to find but it says that it's based on the original Oak Ridge MSR design.
"Old proposed single fluid designs promising breeding performance tend to have an unsafe positive void coefficient and often assume excessive fuel cleaning to be economic viable."
This. Is there any organization on earth - government, corporation, whatever - with even a mediocre track record for commercial-scale deployment of (fairly) radical new nuclear power technologies?
The whole country is structured so that verification by foreigners is next to impossible:
Foreign journalists cannot freely report from within the country. If the government does not like your reporting, you are forced to leave the country.
Information controls ensure that communication with China & the western world is controlled and subject to scrutiny. People in China cannot legally access most foreign news, or communicate with foreigners on social media. You cannot even access hackernews legally in China!
This creates an environment where it's extremely hard to actually vet any information about China, as there is such a strong communications barrier. Both for professional journalists and regular civilians. There is this immense culture of secrecy and information control that does not exist on the same scale anywhere else in the world.
Unsurprisingly this creates a situation where people distrust the words of the Chinese government. They have created this apparatus that prevents foreigners from verifying Chinese information.
It is widely known that when the new coronavirus emerged in December 2019, the Chinese government downplayed the pandemic threat for several critical weeks. Less commonly known is those same authorities deliberately sacrificed health workers to maintain their lies.
The Chinese Communist Party’s (CCP) calculated cover-up enabled the coronavirus to go global. By silencing doctors, Beijing not only fueled this pandemic but also compromised the world’s ability to spot the next one.
Readit News
Everyone sings their praises, but what engineering challenges are there and are those engineering challenges large enough to discourage their development/adoption?
The biggest thing I have found is that the salt solution for Thorium reactors is quite corrosive and that is challenging to contain.
It generally sounds really promising - even the Wiki page for thorium MSR sings its praises.
Why wouldn't it work? Why isn't the world throwing shit-loads of money at this? Is China enlightened or is this some kind of meme-ware technology they fell for (or are trying to convince others to waste their money on)?
https://whatisnuclear.com/thorium-myths.html
Misconception #1: I assume this is listed first because it is the biggest reason Thorium reactors weren't pursued? But really most MSR people seem to view it as political, and the bullet points in "Misconception #1" only underline that.
Misconception #2: Almost all MSR presentations seem to assume a fissile "ignition" supply of uranium, that isn't hidden. And it seems to dovetail with the political opposition, since the regulatory agencies will block the supply of fissile uranium to start an MSR with. So this point seems to again highlight artificial/bureaucratic blockades.
Miconception #3: Well, ok, this seems to be a decent answer based on the fundamentals of the science and engineering.
Misconception #4: This seems to ignore the fact that a very very small amount of uranium is naturally fissile, while the Thorium all breeds to fissile. It also spouts off about seawater extraction, which hasn't happened AFAIK. This answer seems very misleading.
Plus, the fact the author is from a competing design (a pebble design I believe, and one of the reasons pebble designs seem to exist is because of the prohibition on research labs from booting up a liquid reactor).
I do agree the unknowns are the vessel degradation from the salts, but materials engineers these days are just so amazingly good.
It just seems frustrating that the overarching influence of regulatory agency stubbornness and lobbying influence of solid fuel rod reprocessors and other fuel makers (who have a monopoly on nuclear fuel production I believe due to the regulatory agencies) is evident in this article.
If it is true that China gets breeder/thorium/liquid reactors going, it all doesn't matter. The US will be a decade behind, and with the anti-nuclear opinions of the US voting populace, that will afford the entrenched interests cover to keep suppressing nuclear.
I suppose it doesn't matter right now. Solar/Wind/Battery is improving so quickly you can't forecast/target a price/budget for a reactor design that is invariably 5-10 years out.
https://gain.inl.gov/SiteAssets/MoltenSaltReactor/Module2-Ov...
Note page 23! Almost all the 137Cs ends up outside of the core, due to sparging of precursors. "Over 40% of [fission products] leave core"
Lots of other issues, particularly with radiation damage and corrosion of reactor structural elements. Unlike in a solid fuel reactor, there is fission going on right at the boundary of the salt. In a LWR, there is a layer of water between the fuel and the reactor structure to provide shielding. There will be non-fuel components of a MSR that are not lifetime components, but will have to be swapped out due to degradation. Some MSR designs are proposing to just swap out the entire reactor vessel because of this.
If you can figure out the molten salt problem you can replace the nuclear reactor with concentrated solar thermal and get solar baseload power without having to worry about meltdowns for way less than the cost of a nuke plant.
[1] https://www.osti.gov/etdeweb/servlets/purl/20823329
[2] https://en.wikipedia.org/wiki/CANDU_reactor
https://en.wikipedia.org/wiki/India%27s_three-stage_nuclear_...
https://www.youtube.com/watch?v=1EFfxMx6WJs
When people say that this or that reactor design is inherently safe, they are talking about first order effects. When the NRC goes into all the details, things always get a bit more complex.
Edit: by the way, nuclear fission reactors can be supercritical (all current commercial ones), or subcritical (those need an external source of neutrons or protons, such as an accelerator). Only subcritical reactors [3] can be truly pasively safe. There are concepts of subcritical reactors that use Thorium as a fuel, but that's not what China is trying here. China is trying a classical Thorium reactor, where Thorium is used to breed fissile Uranium (not the classical U-235, but rather the isotopes U-232 and U-233), and that Uranium in turn proceeds to undergo the (supercritical) fission chain reaction.
[1] https://www.nrc.gov/docs/ML2002/ML20023A318.html
[2] https://www.nrc.gov/docs/ML2023/ML20231A598.pdf
[3] https://en.wikipedia.org/wiki/Subcritical_reactor
Dead Comment
If you think they can’t do this in 9 years, you haven’t been paying attention.
Just to be clear, this is a universal statement. The issue is that there are many factors to consider. There's cost, storage, total output, CO2 and waste production, physical footprint, environmental factors, local resources, and many other parameters that need to be considered when determining what _combination_ of energy sources should be used for an area. I believe that often people abstract these variables out and only concentrate on cost and a secondary factor that supports their point for the specific conversation. We should not be naive and recognize that these are extremely complex systems with equally complex solutions that require significant amounts of nuance to accurately discuss.
If you say LESS dispersed radiation? Sure. None... sorry not chemically or mechanically or hydraulically or meteorologically plausible.
The elephants foot degrades over time into dust. Radiation causes stress fractures in solids, crystalline structure disturbs. It's going to "decay" in the non radiative sense of the word.
Btw I am pro nuke, in Hypothesis. In my economy (oz) it would have been ideal 30 years ago. Now, with zero power nukes (only one medical manufacturer with a dido type swimming pool reactor) the build out is probably economically infeasible after lawsuit attack, compared to solar, wind and battery. But I remain hopeful of this new stuff, and the PBMR
[0] https://en.wikipedia.org/wiki/Boiling_liquid_expanding_vapor...
These plants offer continuous power with minimal maintenance. Renewable equipment needs to be replaced and repaired at a higher frequency. They will also need storage and grid upgrades to stand as a direct replacement. They absolutely have a place in the energy profile. But, nuclear provides a type of base power that cannot be easily or cost efficiently accomplished by renewable technologies. We need to take advantage of the pros and mitigate the cons of each technology.
Deleted Comment
Dead Comment
IMHO, claims like this from them should be believed 100%, because to do otherwise invites complacency.
Blaming others, deflection, and dishonesty is a common tactic used by every nation.
Remember when the blackout in 2003 was caused by Canada?
"Canadian officials insisted a massive blackout Thursday across the Northeast and parts of Canada originated in the United States, though U.S. power workers denied that and American officials blamed Canada."
Remember how the 9/11 terrorists also came from Canada? Canada doesn't control entry to the US, and they never came via Canada at all but this was often quoted in the media, as a deflection.
"Not one 9/11 terrorist entered the United States via Canada"
I also think China has proven that it is willing and able to rapidly build infrastructure. That makes me think their timeline can be in the right ballpark, too.
They also seem to have been willing to sacrifice quality for speed in large infrastructure projects, though (https://en.wikipedia.org/wiki/Wenzhou_train_collision, https://www.reuters.com/article/idINIndia-40638820090627, https://www.npr.org/2012/08/29/160231137/chinese-blame-faile...)
That’s something I would worry more about (disclaimer: China is huge, so it will have its share of disasters. It also probably will pay more attention to nuclear projects than to bread-and-butter concrete pouring for buildings and roads)
[1] https://twitter.com/ConradKnauer
This moderator develops cracks during normal operation as seen in UK's AGR several other designs. And it burns in case of an accident (Windscale, Chernobyl). Since the TMSR-LF1 is an experimental project I also assume that it's a single fluid design? More detailed information on the TMSR-LF1 is quite hard to find but it says that it's based on the original Oak Ridge MSR design.
"Old proposed single fluid designs promising breeding performance tend to have an unsafe positive void coefficient and often assume excessive fuel cleaning to be economic viable."
https://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reacto...
Hackernews styles itself of thoughtful discussion
Deleted Comment
Deleted Comment
Are you able to substantiate that claim?
Foreign journalists cannot freely report from within the country. If the government does not like your reporting, you are forced to leave the country.
Information controls ensure that communication with China & the western world is controlled and subject to scrutiny. People in China cannot legally access most foreign news, or communicate with foreigners on social media. You cannot even access hackernews legally in China!
This creates an environment where it's extremely hard to actually vet any information about China, as there is such a strong communications barrier. Both for professional journalists and regular civilians. There is this immense culture of secrecy and information control that does not exist on the same scale anywhere else in the world.
Unsurprisingly this creates a situation where people distrust the words of the Chinese government. They have created this apparatus that prevents foreigners from verifying Chinese information.
https://foreignpolicy.com/2021/03/18/china-covid-19-killed-h...
It is widely known that when the new coronavirus emerged in December 2019, the Chinese government downplayed the pandemic threat for several critical weeks. Less commonly known is those same authorities deliberately sacrificed health workers to maintain their lies.
The Chinese Communist Party’s (CCP) calculated cover-up enabled the coronavirus to go global. By silencing doctors, Beijing not only fueled this pandemic but also compromised the world’s ability to spot the next one.
Dead Comment