Fact-check: Five claims about thorium made by Andrew Yang(thebulletin.org)
thebulletin.org
Fact-check: Five claims about thorium made by Andrew Yang
https://thebulletin.org/2019/12/fact-check-five-claims-about-thorium-made-by-andrew-yang/#
19 comments
It is useless to make claims about a particular fuel without looking at a concrete reactor design. Leftover isotopes for example are very dependent on neutron flux and neutron energy as well as general breeding properties of the reactor. This in turn decides the waste to be dealt with, proliferation risk and possible reuse of leftover fuels from previous generation reactors (which the submission didn't even discuss).
Also, the answers lack nuance. E.g. proliferation risk is present through U233, however, U233 seems very difficult to deal with in bombmaking. So at least it's less of a problem maybe.
Also, the answers lack nuance. E.g. proliferation risk is present through U233, however, U233 seems very difficult to deal with in bombmaking. So at least it's less of a problem maybe.
Its easy to make bombs from U-233. In fact it is better than plutonium in some rare circumstances. Check out the discussion and cool declassified letter from the Livermore bomb letters here: https://whatisnuclear.com/thorium-myths.html#myth3
Yes, making the bombs themselves seems to be easy. The difficulty comes from U232-contamination which decays into strong gamma emitters, making handling difficult. However, there seem to be paths for the production of pure U233 from chemically separated Pa233, which one might be doing anyways in a thorium reactor. That would mean a significantly higher proliferation risk, because one would get pure bomb fuel form the normal operations of the reactor. However, I don't know enough about how easy or likely that would be to judge.
But in all, you are right, I think. And maybe even more than right.
But in all, you are right, I think. And maybe even more than right.
I mean to say that making clean U-233 (with very little U-232 and daughters) is easy. Certainly assembling a bomb given pristene weapons material is particularly easy.
I'm a reactor designer and study this kind of thing. It's really just a question of how fast you move your Th-232 through a neutron cloud. If you move it relatively quickly and then do your Pa separation you can get very nice U-233 from Thorium.
The nice thing here about low-pressure fluid fuel reactors is that you can move material in and out fairly readily.
I'm a reactor designer and study this kind of thing. It's really just a question of how fast you move your Th-232 through a neutron cloud. If you move it relatively quickly and then do your Pa separation you can get very nice U-233 from Thorium.
The nice thing here about low-pressure fluid fuel reactors is that you can move material in and out fairly readily.
Several things in this FAQ are frequently contradicted, which I'm not sure what to make of.
They are not wrong, but also not right in all scenarios. Truth very much depends on the reactor design.
Thorium is often associated with Gen4 reactors which are responsible for the claims of superior safety. Not much, but some of the safety benefit comes from thorium. Similar for the claim of less waste: Some reactors have better neutron economy, burning their own waste down to more shortlived and therefore "better" isotopes. Or, by the same mechanism, can utilize existing waste as fuel. Also, continuous loading and separation of isotopes only works well with liquid fuels which is a Gen4 idea.
Thorium is more of a side-topic there.
On the economic side of whether thorium is cheaper, the submission argues in a very underhanded manner. Yes, fuel is cheap compared to building the plant in all cases. But the fuel cost of thorium is an order of magnitude below uranium due to no enrichment (for light water reactors in the fuel, for heavy water reactors of the water). And possibly (for liquid core reactors) the unnecessary fuel elements production.
Thorium is more of a side-topic there.
On the economic side of whether thorium is cheaper, the submission argues in a very underhanded manner. Yes, fuel is cheap compared to building the plant in all cases. But the fuel cost of thorium is an order of magnitude below uranium due to no enrichment (for light water reactors in the fuel, for heavy water reactors of the water). And possibly (for liquid core reactors) the unnecessary fuel elements production.
The FRONT END of the fuel cost is lower. But in a molten salt reactor with fuel dissolved in the salt, reprocessing is not optional! The fission products have to be removed from the fuel salt at some point (reprocessing) because the salt is expensive (especially FLiBe). So the back end of the fuel cycle will impose costs that do not exist with today's once through fuel cycles.
> But the fuel cost of thorium is an order of magnitude below uranium due to no enrichment
This turns out not to be true in practice. Uranium-238 is fertile just like Thorium-232. To run a reactor off either of these fertile fuels requires breeder reactor technology, which involves chemical separations and exotic fluids. In practice, this has always been more expensive, even though the U-238 or Th-232 is not enriched. It turns out that breeder reactor infrastructure outweighs the cost reduction in not having to enrich.
In fact, this is the primary reason that we don't have any breeder reactors today: it's simply cheaper to mine and enrich uranium than to reprocess. There are political reasons as well, but the primary reason is this economics.
This turns out not to be true in practice. Uranium-238 is fertile just like Thorium-232. To run a reactor off either of these fertile fuels requires breeder reactor technology, which involves chemical separations and exotic fluids. In practice, this has always been more expensive, even though the U-238 or Th-232 is not enriched. It turns out that breeder reactor infrastructure outweighs the cost reduction in not having to enrich.
In fact, this is the primary reason that we don't have any breeder reactors today: it's simply cheaper to mine and enrich uranium than to reprocess. There are political reasons as well, but the primary reason is this economics.
Yang is to be credited for stating he is open to all possible solutions to the climate crisis, and rightly pointing out that with a crisis of this magnitude no solutions should be taken off the table at this point. Something other candidates are reluctant to do when it comes to the topic of nuclear energy.
He shouldn’t be expected to be an expert in the nuances of the technology or fuels. This should always be left to the appropriate experts in the Dept of Energy, etc. The job of the president should be to identify the problem (in this case climate change), and task the appropriate agencies with solving it, which will involve a variety of actions.
He shouldn’t be expected to be an expert in the nuances of the technology or fuels. This should always be left to the appropriate experts in the Dept of Energy, etc. The job of the president should be to identify the problem (in this case climate change), and task the appropriate agencies with solving it, which will involve a variety of actions.
Exactly. The takeaway should be that Yang is approaching this issue from a position of technical merit and not on an irrational emotional basis like most others. This is to his credit. Properly technocratic leadership is rare in the USA and it's beyond time for them to experiment with it.
In my opinion the analysis linked to from HN is laughably flawed. It's not exactly wrong, but it's so terse and reductive that it might as well be. For example— while the waste from the thorium fuel cycle could be used to make weapons, but the fuel would always include some Uranium 232 (a gamma emitter) and therefore it's more difficult to handle safely and your entire weapon manufacturing pipeline is able to be monitored from afar by foreign governments.
In my opinion the analysis linked to from HN is laughably flawed. It's not exactly wrong, but it's so terse and reductive that it might as well be. For example— while the waste from the thorium fuel cycle could be used to make weapons, but the fuel would always include some Uranium 232 (a gamma emitter) and therefore it's more difficult to handle safely and your entire weapon manufacturing pipeline is able to be monitored from afar by foreign governments.
Re: Yang is approaching this issue from a position of technical merit and not on an irrational emotional basis like most others.
Unfortunately, politics is not rational. Energy sources that kill slowly but gradually make less news and attention than "death spike" patterns even if their long-term-average numbers are better. If you don't address political patterns, then you will be bulldozed by trolls and demagogues who leverage emotion and vague impressions. If you go on the news with death-rate charts, you'll be ridiculed by the same people who beat up and shunned nerds in school. I'm just the messenger.
Unfortunately, politics is not rational. Energy sources that kill slowly but gradually make less news and attention than "death spike" patterns even if their long-term-average numbers are better. If you don't address political patterns, then you will be bulldozed by trolls and demagogues who leverage emotion and vague impressions. If you go on the news with death-rate charts, you'll be ridiculed by the same people who beat up and shunned nerds in school. I'm just the messenger.
Technically the big gamma emitter is Tl-208 which is in the decay chain of U-232.
Careful about downplaying the U-233 weapons potential. Phenomenal nuclear weapons can be derived from Thorium. Here's a good declassified hint from 1966: https://www.osti.gov/biblio/79078
Careful about downplaying the U-233 weapons potential. Phenomenal nuclear weapons can be derived from Thorium. Here's a good declassified hint from 1966: https://www.osti.gov/biblio/79078
You are right on him not needing to be an expert. However these are not nuances - the idea of Thorium reactors has been around for decades and the key reasons it is hard to make it work and safe have not changed. If he has not an expert at hand now who can tell him that Thorium reactors are unlikely that calls into question his ability to find and select advisors. Jumping on solutions that are looking good and convenient is not a qualification for the job.
This is giving him quite a soft pass. If he's made specific claims about thorium reactors then it's good that they're being fact-checked.
I like that he mentions geo-engineering. To me, the most promising is stratospheric aerosol injection. I don't understand why there's not more talk about it given the cost / value ratio.
If it turns out that there are no serious side effects or risk and governments agree to do it, we have solved climate change.
If it turns out that there are no serious side effects or risk and governments agree to do it, we have solved climate change.
This pro geologist (James Conca) is talking about it. His favorite option is crushed shells/limestone. The side-effect is that they reduce ocean acidification.
https://www.forbes.com/sites/jamesconca/2019/09/10/solar-geo...
https://www.forbes.com/sites/jamesconca/2019/09/10/solar-geo...
> If it turns out that there are no serious side effects or risk
Literally the only way to determine that would be to try it. And then let’s hope the proponents are correct, because if not...
There is just so much we don’t understand about the global climate to think this sort of solution is a good idea. I’ll start taking the geoengineering people seriously when they can accurately predict the weather one month from now.
Literally the only way to determine that would be to try it. And then let’s hope the proponents are correct, because if not...
There is just so much we don’t understand about the global climate to think this sort of solution is a good idea. I’ll start taking the geoengineering people seriously when they can accurately predict the weather one month from now.
Predicting weather and predicting climate are almost completely different things. It's about predicting where a single state space trajectory of a chaotic system ends up versus predicting bounds and average positions for an ensemble of trajectories. The first is impossible, the second is routinely done. Think of a double pendulum, one can't predict where it is in an hour, but can predict reasonably accurately how high it can still go due to the amount of kinetic and potential energy it is going to have.
Dimming sunlight will reduce plant growth. CO2 extraction is more expensive but less worrying than any deflection-based technology in terms of side effects IMO.
You could cover the desert with aluminum foil I guess. Might confuse the birds.
You could cover the desert with aluminum foil I guess. Might confuse the birds.
Also dimming might also have some effects on the fauna too. I know it’s a small change but on a global scale I bet there would be some pathology for humans and other animals.
Absolutely, we've already been geo-engineering for the past 150 years by burning fossil fuels. The tricky part will be how to deal with different governments... what if a project to increase rainfall in the Gobi desert decreases rainfall in California?
Yeah, I really appreciate that he has the courage to say things that need to be said, even though he knows it's currently unpopular. The adult in the room.
Which indicates he's genuinely interested in solving problems. Politics and focus groups be damned. As such it seems likely he'd update his priors via field experts.
Which indicates he's genuinely interested in solving problems. Politics and focus groups be damned. As such it seems likely he'd update his priors via field experts.
Him not being an expert is not an excuse for spreading incorrect information. He could have asked one. I am truly amazed how easy people tend to let their favorite politicians off the hook for saying dumb things in public.
If he's going to rely on experts this would certainly be one place to demonstrate that.
I'm involved in a public education nuclear website. We get tons of questions about thorium so we made a few pages to handle stuff like this. For instance, we have one on molten salt reactors specifically (which aren't always fueled with thorium) [1].
[1] https://whatisnuclear.com/msr.html
And then we have our most popular, the Thorium Myths page [2].
[2] https://whatisnuclear.com/thorium-myths.html
I love that Yang is bringing the discussion to the capabilities of nuclear technology even if I consider it a bit misguided to focus on the thorium fuel cycle. There's a phrase in nuclear advocacy today: "Come for the thorium, stay for the reactors"
[1] https://whatisnuclear.com/msr.html
And then we have our most popular, the Thorium Myths page [2].
[2] https://whatisnuclear.com/thorium-myths.html
I love that Yang is bringing the discussion to the capabilities of nuclear technology even if I consider it a bit misguided to focus on the thorium fuel cycle. There's a phrase in nuclear advocacy today: "Come for the thorium, stay for the reactors"
The thing I hate most in nuclear advocacy is the trope of "the new, exciting, safe and economical nuclear reactor based on new, exciting miracle tech!".
We have amazing, safe, economical, etc. nuclear reactors. They're called nuclear reactors, and don't need any miracle tech conjured up in some magazine columnist's imagination.
We have amazing, safe, economical, etc. nuclear reactors. They're called nuclear reactors, and don't need any miracle tech conjured up in some magazine columnist's imagination.
Today's Thorium "hype" was started by a NASA tech named Kirk Sorensen. He outwardly said nuclear needed a rebrand as early as 2008 and has kind of doubled down on it. Like: "Hey all those problems with nuclear are solved if you split this nucleus instead of that one". I agree with you and don't think this is necessary.
We should just try to help people see context in the things they don't like about nuclear. The reactor accidents we all have heard about are hard for anyone to compare with 8 million air pollution deaths per year from combustion. But few people know about the Banqiao dam failure that killed 100,000.
I read recently that 60% of American's think nuclear reactors contribute to climate change, when in fact they're among the lowest carbon forms of energy known.
It's really mostly a PR issue. Nuclear PR money is tied up in utilities which also all run large fossil assets, so it's rare for them to talk about how low carbon nuclear is.
We should just try to help people see context in the things they don't like about nuclear. The reactor accidents we all have heard about are hard for anyone to compare with 8 million air pollution deaths per year from combustion. But few people know about the Banqiao dam failure that killed 100,000.
I read recently that 60% of American's think nuclear reactors contribute to climate change, when in fact they're among the lowest carbon forms of energy known.
It's really mostly a PR issue. Nuclear PR money is tied up in utilities which also all run large fossil assets, so it's rare for them to talk about how low carbon nuclear is.
Nuclear accidents have unique and sometimes unpredictable environment impact, like Fukushima continuing to pollute the ocean with radioactive material to this day.
Not saying that's a good reason to swear ourselves off nuclear, but it's more complicated than low carbon emissions.
Not saying that's a good reason to swear ourselves off nuclear, but it's more complicated than low carbon emissions.
I agree that it's complicated.
Radiological hazards are indeed pretty unique in the human experience. I disagree that any given release has unpredictable impact though. Top scientists around the world have studied the effects of radiation on living things and the environment in elaborate detail for 80 years. We have vast amounts of good data. This really became political around 1953 as the radioactive fallout from the big atmospheric thermonuclear weapons became extremely serious. The entire environmentalist movement itself was born out of protests against radiological hazards from weapons testing.
Where climate science has the IPCC, heath effects of radiation has UNSCEAR [1], a UN-organized international group of top scientists.
[1] https://www.unscear.org/
The number one argument for nuclear is that it dramatically reduces air pollution deaths by displacing fossil fuel. The carbon-free nature you mention is argument number 2 in my mind. Number 3 is that it can run 24/7 and be deployed in a wide variety of geographies.
As for polluting the ocean at Fukushima, I recommend seeing what Jim Conca has to say on it [2]. He's one of the world experts in nuclear waste.
[2] https://www.forbes.com/sites/jamesconca/2019/09/12/its-reall...
Radiological hazards are indeed pretty unique in the human experience. I disagree that any given release has unpredictable impact though. Top scientists around the world have studied the effects of radiation on living things and the environment in elaborate detail for 80 years. We have vast amounts of good data. This really became political around 1953 as the radioactive fallout from the big atmospheric thermonuclear weapons became extremely serious. The entire environmentalist movement itself was born out of protests against radiological hazards from weapons testing.
Where climate science has the IPCC, heath effects of radiation has UNSCEAR [1], a UN-organized international group of top scientists.
[1] https://www.unscear.org/
The number one argument for nuclear is that it dramatically reduces air pollution deaths by displacing fossil fuel. The carbon-free nature you mention is argument number 2 in my mind. Number 3 is that it can run 24/7 and be deployed in a wide variety of geographies.
As for polluting the ocean at Fukushima, I recommend seeing what Jim Conca has to say on it [2]. He's one of the world experts in nuclear waste.
[2] https://www.forbes.com/sites/jamesconca/2019/09/12/its-reall...
That second article talks a whole lot about how tritium can't hurt humans but then says that keeping the contaminated water in tanks poses a risk to humans...
I think the second point is that if insist that tanks with tritium are indeed dangerous (which the first point argued against), then you should want the hazard eliminated (by dilution) to avoid hurting living things.
Everything has unpredictable environment impact at this scale. Name one energy source that can replace nuclear that doesn't have hard-to-predict consequences of unknown but possibly gigantic magnitude on a global scale.
That's exactly my point, nuclear is not some magical exception to this rule
Manufacturing the equivalent obscene number of solar and wind power plants also has unique and unpredictable environmental impact.
There's a reason we call MRI machines MRIs, and not NMRIs. Rebranding around public perception matters, whether we like it or not.
Yeah, but I think just calling nuclear energy thorium or quantum energy or whatever is too shallow. The nuclear element of nMRI is kind of peripheral, but I don't think anyone will let you do that with mass-to-energy conversion power plants.
With airplanes, everyone knows they're really safe. Everyone says they're safer than cars. People are still afraid of airplanes but they're reassured. It'd be nice if nuclear fission could get to this level in the public zeitgeist.
With airplanes, everyone knows they're really safe. Everyone says they're safer than cars. People are still afraid of airplanes but they're reassured. It'd be nice if nuclear fission could get to this level in the public zeitgeist.
> With airplanes, everyone knows they're really safe. Everyone says they're safer than cars.
Though true by many metrics, the fact that this has entered into the public zeitgeist is a victory in marketing.
While commercial air travel is much safer per hour and per KM, it is less safe by the metric used by the industry and its insurers: Deaths per journey.[1]
However, there's a strong argument to be made that time and distance are more relevant to the consumer anyways. Still, the per-journey metric could have been weaponized by an opponent of commercial air travel to assert the opposite.
[1]: https://www.newscientist.com/article/mg16321985-200-flight-i...
Though true by many metrics, the fact that this has entered into the public zeitgeist is a victory in marketing.
While commercial air travel is much safer per hour and per KM, it is less safe by the metric used by the industry and its insurers: Deaths per journey.[1]
However, there's a strong argument to be made that time and distance are more relevant to the consumer anyways. Still, the per-journey metric could have been weaponized by an opponent of commercial air travel to assert the opposite.
[1]: https://www.newscientist.com/article/mg16321985-200-flight-i...
> There's a reason we call MRI machines MRIs, and not NMRIs
My dad sold microwaves when they were new; they were careful never to say "radiation" or "irradiated" or anything like that.
My dad sold microwaves when they were new; they were careful never to say "radiation" or "irradiated" or anything like that.
I don't buy it. For example in Germany MRI is usually called "Kernspintomographie" ("nuclear spin tomography") and nobody has any issue with that.
And yet I can't step out my door without finding anti nuclear posters and stickers in Germany. I've never seen this for any other topic: not Jesus, not Snowden asylum, not je suis charlie, but nuclear power? Somehow someone managed to setup a hugely effective brainwashing campaign for that.
And the field in the United States is 'nuclear medicine', a specialty of 'radiology'. And, well, an 'x-ray' is called an 'x-ray' not a 'bone selfie'.
Isn't it more commonly called "Magnetresonanztomographie" (MRT) now? Same PR problem, people are scared of atoms.
It was genuinely a problem here in the US.
https://pdfs.semanticscholar.org/4a3e/c44df38873b8bf1e79a30e...
https://pdfs.semanticscholar.org/4a3e/c44df38873b8bf1e79a30e...
If it’s a PR issue, then wouldn’t a re-branding (I.e. “thorium isn’t the uranium nuclear you know and fear”) be an appropriate solution? At least, assuming thorium isn’t so much worse than current reactor designs?
What is an economical reactor model available to be built today? Practically every commercial reactor built seems to be a multi-billion dollar project that takes years to complete, with cost overruns common.
Shipyard-constructed several-hundred-megawatt pressurized water reactors. The Navy has basically achieved economies of mass production with their reactors. The submarine and aircraft carrier weapons systems are expensive, but if you just did something similar for civilian power, I believe you could capture both economies of scale and economies of mass production. For decarbonizing the world very rapidly, this would be my going-in plan (if I could choose).
Nuclear success stories are stories of standardization of design and repetition. Most of the boondoggles are first-of-a-kind or first-in-2-decades builds.
Nuclear success stories are stories of standardization of design and repetition. Most of the boondoggles are first-of-a-kind or first-in-2-decades builds.
Which Navy models have economies of scale? These reactors look to be built on contract from a variety of vendors. Additionally these designs look to prioritize small size and lack of need to refuel over fuel flexibility and refuelability, plus they have power output constraints due to size compared to land-based reactors.
Both Chernobyl's RBMK and Fukushima's GE BWR reactors are widely used standard designs.
Chernobyl was a combination of issues and can't really happen again today. Fukushima is bad but very few people died (counting those that'll get cancer). Many, many, many more people die from the pollution caused by coal every year, and many, many more will die from global warming.
If one such failure amongst hundreds of reactors active for over fifty years is the price of saving millions every year, then so be it. We should use solar/wind/water to the full extent possible but not exclude nuclear energy, especially with the latest factor designs. And you can bet that Japan learned from Fukushima and that it's very unlikely that'll reoccur as well. Plus, most reactors aren't built near major fault lines, so this failure isn't even possible in most places. Let's not kill millions because of a TV drama. It's news exactly because it's rare, that's why you don't hear of people dying while installing roof solar or from air pollution.
If one such failure amongst hundreds of reactors active for over fifty years is the price of saving millions every year, then so be it. We should use solar/wind/water to the full extent possible but not exclude nuclear energy, especially with the latest factor designs. And you can bet that Japan learned from Fukushima and that it's very unlikely that'll reoccur as well. Plus, most reactors aren't built near major fault lines, so this failure isn't even possible in most places. Let's not kill millions because of a TV drama. It's news exactly because it's rare, that's why you don't hear of people dying while installing roof solar or from air pollution.
RBMK were. They're over 50 year old designs now. Fukushima was just 30 years old also generation 2 (but improved) BWR, not the old GE BWR either. The reactors under way are generation III+, notably safer, and further improvements are being made. And many of the reactors now are PWR.
> ... with cost overruns common.
Presumably that is going to be consistent with any large industrially planned operation though. The overruns aren't going to be technology-specific, they are going to be related to the tendering process.
If the planners are incentivised for accuracy there will be one, maybe two overrun projects then the assumptions get adjusted. So if it is routine that suggests that there is some sort of incentive problem.
An industry planner will have little difficulty estimating an accurate cost of the technical parts of a project. Using historic averages or model + 20% contingency usually gets most of the way there. If the estimates are consistently wrong there are political issues at play.
Presumably that is going to be consistent with any large industrially planned operation though. The overruns aren't going to be technology-specific, they are going to be related to the tendering process.
If the planners are incentivised for accuracy there will be one, maybe two overrun projects then the assumptions get adjusted. So if it is routine that suggests that there is some sort of incentive problem.
An industry planner will have little difficulty estimating an accurate cost of the technical parts of a project. Using historic averages or model + 20% contingency usually gets most of the way there. If the estimates are consistently wrong there are political issues at play.
Fear and doubt -> rare and unique reactors -> no economy of scale -> poor economic results -> more fear and doubt :(
The pivot to Thorium is to some extent a marketing issue. The "amazing safe economical" modern reactors have a tarnished reputation, possibly irreversibly so, given the political unpopularity today.
> similar radioactivity at 100 years to uranium-plutonium fuel cycles, and actually has higher waste radioactivity at 100,000 years
At 100 years your radioactivity is still dominated by fission products, which are the same in either reactor. At 100,000 years the radioactivity is minuscule with any reactor.
But what you don't have with thorium or fast uranium reactors is a lot of transuranic waste, like plutonium. That's the stuff that people think has to be contained for 10,000 years. With just fission products, you're back to the radioactivity of the original ore in 300 years. You do get a bit of very long-lived fission product but it's not much radioactivity.
Also, the total volume of waste is about 1% as much as with conventional reactors, since 99% of conventional waste is (mostly) U238, some leftover U235, and transuranics. A molten salt fast reactor will fission all of that very effectively, and a thorium reactor doesn't have the U238 or make as much transuranic in the first place.
At 100 years your radioactivity is still dominated by fission products, which are the same in either reactor. At 100,000 years the radioactivity is minuscule with any reactor.
But what you don't have with thorium or fast uranium reactors is a lot of transuranic waste, like plutonium. That's the stuff that people think has to be contained for 10,000 years. With just fission products, you're back to the radioactivity of the original ore in 300 years. You do get a bit of very long-lived fission product but it's not much radioactivity.
Also, the total volume of waste is about 1% as much as with conventional reactors, since 99% of conventional waste is (mostly) U238, some leftover U235, and transuranics. A molten salt fast reactor will fission all of that very effectively, and a thorium reactor doesn't have the U238 or make as much transuranic in the first place.
A few points:
* Uranium-Plutonium fuel in a closed cycle can burn all the transuranics and have very low radiotoxicity waste as well.
* Molten salt fuels are 10x less dense than typical solid fuels, implying an increase in waste volume. They're also water soluble and frequently liquid. This complicates waste disposal and transport. Not terribly, but still.
A good summary reference on radiotoxicity vs. reprocessing is: https://www.iaea.org/publications/8359/assessment-of-partiti...
* Uranium-Plutonium fuel in a closed cycle can burn all the transuranics and have very low radiotoxicity waste as well.
* Molten salt fuels are 10x less dense than typical solid fuels, implying an increase in waste volume. They're also water soluble and frequently liquid. This complicates waste disposal and transport. Not terribly, but still.
A good summary reference on radiotoxicity vs. reprocessing is: https://www.iaea.org/publications/8359/assessment-of-partiti...
A uranium-plutonium fuel in a closed cycle can do that if you have fast reactors. Thermal reactors, no. And the higher transuranics become increasingly difficult to burn, since the delayed neutron fraction goes way down. A reactor burning higher transuranics will be right on the knife edge of prompt supercriticality.
> A reactor burning higher transuranics will be right on the knife edge of prompt supercriticality.
Meh, that might be a bit of an overstatement. Yes, plutonium-driven fast reactors have a delayed neutron fraction around 0.0035 down from 0.0065 in a U-235-fueled fast reactor. The relatively large delayed neutron fraction from fast fissions of U-238 helps out along the way. You can reduce the radiotoxicity of TRU even if you continue to load some U-238. The inert matrix fuels with no U-238 at all get more interesting from this perspective (also from the Doppler effect), but most people don't envision using these.
In fluid systems, more than half of the fuel inventory is off in a heat exchanger out of the core, which means the delayed neutron fraction is cut roughly in half in those systems too (the delayed neutron precursor decays happen where neutron importance is near zero).
Plutonium-fueled fast reactors can be operated with good margins of stability.
Meh, that might be a bit of an overstatement. Yes, plutonium-driven fast reactors have a delayed neutron fraction around 0.0035 down from 0.0065 in a U-235-fueled fast reactor. The relatively large delayed neutron fraction from fast fissions of U-238 helps out along the way. You can reduce the radiotoxicity of TRU even if you continue to load some U-238. The inert matrix fuels with no U-238 at all get more interesting from this perspective (also from the Doppler effect), but most people don't envision using these.
In fluid systems, more than half of the fuel inventory is off in a heat exchanger out of the core, which means the delayed neutron fraction is cut roughly in half in those systems too (the delayed neutron precursor decays happen where neutron importance is near zero).
Plutonium-fueled fast reactors can be operated with good margins of stability.
I was talking about elements beyond plutonium.
Something people dislike being pointed out. As far as reprocessing is concerned the best first step in reprocessing spent fuel rods is not fuck with them for a hundred years.
I'd go so far to say we should just dispose of it all. I used to be all in on reprocessing the waste. Nowadays I only want to do it if it's actually cheaper (which I don't think it will be for many decades). Nuclear has economics issues, not uranium sustainability issues. Uranium from seawater with runoff can power the entire planed 10x over for a few hundred million years. It's borderline renewable. We need to be doing things that make nuclear reactors simpler and cheaper to operate, not more complex and expensive.
Disposing of the waste from a once-through fuel cycle is totally doable. We just have to let the world know that the Finns are doing it at the Onkalo Repository, we can do it in WIPP, and Deep Isolation LLC is working on a pretty slick deep borehole option.
Disposing of the waste from a once-through fuel cycle is totally doable. We just have to let the world know that the Finns are doing it at the Onkalo Repository, we can do it in WIPP, and Deep Isolation LLC is working on a pretty slick deep borehole option.
I didn't realize molten salt fuel is 10X less dense. But assuming either thorium or fast uranium reactors, they'll get 100X as much energy from the fuel, making 10X less fuel volume than conventional reactors.
That doesn't necessarily imply anything about the waste volume. With high burnup, the waste is just fission products, which are entirely different elements than the fuel.
One reason high burnup is easier in MSRs is that xenon, a neutron poison, is a gas that just bubbles out of the liquid fuel, instead of being trapped in a solid. With fast uranium or thermal thorium, you also don't have a large amount fuel that can't be fissioned. (Some early MSRs will be thermal uranium, and produce more waste.)
For disposal of fission products, the general idea is to mix them into glass and bury them as solid blocks.
That doesn't necessarily imply anything about the waste volume. With high burnup, the waste is just fission products, which are entirely different elements than the fuel.
One reason high burnup is easier in MSRs is that xenon, a neutron poison, is a gas that just bubbles out of the liquid fuel, instead of being trapped in a solid. With fast uranium or thermal thorium, you also don't have a large amount fuel that can't be fissioned. (Some early MSRs will be thermal uranium, and produce more waste.)
For disposal of fission products, the general idea is to mix them into glass and bury them as solid blocks.
im not sure it's useful to hold yang accountable for such technical minutae. i generally believe that nuclear has an important role to play in our mitigation of climate change, but that our bias to remember flash-point events like chernobyl and fukushima will overshadow the far more deadly and ubiquitous proliferation of CO2 and methane that lacks the same "pizazz"
And it's important to remember that the Fukushima nuclear disaster has caused one confirmed death so far. I'm not saying that it wasn't a horrific disaster, but it's like comparing one dramatic aeroplane accident to the totality of road vehicle deaths worldwide—one plane is newsworthy; whereas the vehicle death toll is normalised and ignored.
Worldwide, around 50 to 500 people die in planes each year.
Worldwide, over 1 million people die in cars each year.
Worldwide, around 50 to 500 people die in planes each year.
Worldwide, over 1 million people die in cars each year.
The Fukushima nuclear disaster came close to forcing the Japanese Prime Minister to shut down and evacuate Tokyo. [1]
Also, you are making an error in how you calculate risk. It's not just how many fatalities are caused by each source of risk on an annual basis. It's also how much potential a risk-source has to scale. Nuclear can potentially scale into causing a massive number of fatalities and that is why people, correctly, identify it as a serious source of risk.
[1] https://www.nytimes.com/2012/02/28/world/asia/japan-consider...
Also, you are making an error in how you calculate risk. It's not just how many fatalities are caused by each source of risk on an annual basis. It's also how much potential a risk-source has to scale. Nuclear can potentially scale into causing a massive number of fatalities and that is why people, correctly, identify it as a serious source of risk.
[1] https://www.nytimes.com/2012/02/28/world/asia/japan-consider...
Do you remember what else happend that day at Fukushima? 15k people died from the tsunami. Yet people could not tell you anything about the tsunami except that it caused problems at the reactor.
Well, to be fair, people in Japan mostly remember the tsunami. In the town where I live beach front property is half the price of property on top of the hill these days.
People are also concerned about nuclear reactor safety. I live about 6 km from a nuclear reactor and there are repeated calls to dismantle it. I frequently get visits from PR people from the power company to try to convince me that the nuclear reactor is necessary. It's a short conversation: I'm very much more inclined to welcome the nuclear power plant than more natural gas! However, this particular power plant has been closed down for almost 15 years. Note this is significantly longer than the time period since the Tohoku earthquake. To be frank, the power company was not able to pass safety checks for years prior to the tsunami. Although it has been significantly upgraded, I'm not surprised that people in the area are afraid.
Even with this, I can tell you that the land literally next door to the power plant is significantly higher priced than the land next to one of the nicest stretches of white sand beach in this part of Japan. People here have a pretty good handle on what's more dangerous.
People are also concerned about nuclear reactor safety. I live about 6 km from a nuclear reactor and there are repeated calls to dismantle it. I frequently get visits from PR people from the power company to try to convince me that the nuclear reactor is necessary. It's a short conversation: I'm very much more inclined to welcome the nuclear power plant than more natural gas! However, this particular power plant has been closed down for almost 15 years. Note this is significantly longer than the time period since the Tohoku earthquake. To be frank, the power company was not able to pass safety checks for years prior to the tsunami. Although it has been significantly upgraded, I'm not surprised that people in the area are afraid.
Even with this, I can tell you that the land literally next door to the power plant is significantly higher priced than the land next to one of the nicest stretches of white sand beach in this part of Japan. People here have a pretty good handle on what's more dangerous.
> And it's important to remember that the Fukushima nuclear disaster has caused one confirmed death so far.
I wish nuclear apologists with an agenda would stop repeating this.
250,000 residents were displaced, many spending their final days in gyms and other camps as rufugees in their own country.
An entire army will spend decades and likely trillions of dollars trying to do something with the shattered remains of the Fukushima complex.
I wish nuclear apologists with an agenda would stop repeating this.
250,000 residents were displaced, many spending their final days in gyms and other camps as rufugees in their own country.
An entire army will spend decades and likely trillions of dollars trying to do something with the shattered remains of the Fukushima complex.
Calling people who disagree with you "apologists with an agenda" isn't really within the spirit of Hacker News, nor is it conducive to healthy discussion.
The disaster that hit Fukushima was a tsunami. Only a very small section of the prefecture is still affected by the fallout and most of that area is for an abundance of caution. Most of the leaked radioactive material went in the best possible place for it—dispersed into ocean water. Ocean water already contains naturally occurring radioactive material, in quantities many orders of magnitude greater than humans could ever hope to disperse "by accident".
Meanwhile, the disaster being faced now could have been similar or ever massively worse if the tsunami had hit and damaged chemical storage plants instead.
The disaster that hit Fukushima was a tsunami. Only a very small section of the prefecture is still affected by the fallout and most of that area is for an abundance of caution. Most of the leaked radioactive material went in the best possible place for it—dispersed into ocean water. Ocean water already contains naturally occurring radioactive material, in quantities many orders of magnitude greater than humans could ever hope to disperse "by accident".
Meanwhile, the disaster being faced now could have been similar or ever massively worse if the tsunami had hit and damaged chemical storage plants instead.
> 250,000 residents were displaced, many spending their final days in gyms and other camps as rufugees in their own country.
For which overreaction to the powerplant failure is partially to blame.
For which overreaction to the powerplant failure is partially to blame.
I just wish he would switch from promoting Thorium to promoting technology development in nuclear. But believe me when I say I'll take what I can get!
Heh. I've been whining that HBO hasn't made a miniseries about the 4 million outdoor air pollution deaths every year or the other 4 million indoor air pollution deaths per year.
Heh. I've been whining that HBO hasn't made a miniseries about the 4 million outdoor air pollution deaths every year or the other 4 million indoor air pollution deaths per year.
I agree with you in principle, but let him focus on thorium during the election process. It's his way of letting us know he's on the correct side of the broader issue without freaking out the hippies.
The fact that we are discussing thorium here and in many other places suddenly, proves the successful mission accomplished by Andrew Yang. Federal bureaucrats and their aides are forced to do their homework to seriously consider the option and answer intelligently.
I don't think that's necessarily true, most of us on HN were probably aware of it as an option for a while considering that the main audience of the site is fairly "tech crazed". I wouldn't necessarily take that to mean he's succeeded in bringing this sort of thing to the attention of the masses.
Particularly since any of the other people who pretend to care about the climate haven't revised their weird "no nuclear" policy despite it all.
Particularly since any of the other people who pretend to care about the climate haven't revised their weird "no nuclear" policy despite it all.
For sure. I'm really glad this is bringing nuclear discussions to the left.
At least the US DOE is already highly knowledgeable about thorium and molten salt reactors. Advanced reactor people at the national labs and elsewhere have been studying this stuff for decades. There are still plenty of us who know the details.
At least the US DOE is already highly knowledgeable about thorium and molten salt reactors. Advanced reactor people at the national labs and elsewhere have been studying this stuff for decades. There are still plenty of us who know the details.
Actually I'm sort of excited about the reverse: there are many interesting topics I've heard about on HN that are going "mainstream" through Yang: Universal Basic Income, ranked choice voting, next-gen nuclear, a lot of musings on incentive structures and their problems, data ownership, etc.
samirillian(2)
I’m quite disappointed by Yang’s false claims. I’ve come to accept him as the truth and logic driven candidate who thinks things through. He could have advocated his position without these statements. He should focus on Gen4.
My primary concern with any for of nuclear reactors is that they make for very juicey targets.
In real life, the few attacks that have been tried against nuclear power plants have "failed" miserably. [1]
It's not terribly hard to shut one down (or at least not much harder than your typical power plant) but extracting/releasing any radioactive material is very, very difficult.
[1] https://www.forbes.com/sites/michaelshellenberger/2018/07/06...
It's not terribly hard to shut one down (or at least not much harder than your typical power plant) but extracting/releasing any radioactive material is very, very difficult.
[1] https://www.forbes.com/sites/michaelshellenberger/2018/07/06...
Even with all that aircraft-impact resistant, highly reinforced containment, crazy off-grid redundant safety systems, and paramilitary guard force a few hundred strong? Honestly I can see how they might be intriguing at first, but after quick consideration I think most attackers would quickly find something easier to hit.
How does this relate to Bill Gates plans? I saw them on Netflix recently [0]
[0] https://www.popularmechanics.com/science/energy/a25728221/te...
[0] https://www.popularmechanics.com/science/energy/a25728221/te...
To my knowledge, the reason why Thorium reactors have never been pursued is because there is no way to weaponise them.
I’m glad someone is talking about new possibilities of carbon free power generation.
I’m glad someone is talking about new possibilities of carbon free power generation.
“Fact checking” seems to be a new synonym for propaganda. I am not sure what trust I should have in fact checking from what looks like an anti-nuclear organisation.
Whether Thorium or not, geo engineering or not, the bigger point being made by Andrew Yang is that all options should be on the table in this crisis, and yes, I believe it is a crisis.
I wish there was this much backlash against Donald Trumps fictional claim that the sound of wind-turbines caused cancer, but i am assuming that this bulletin was commissioned by someone that rather nitpick on Yang for opening a door, than the current presidents attempt to slam working doors shut. Not to make this political, but Yang brings a lot to the table that others ignore afraid of being scrutinized.
This is just whataboutism. Trump's insanity doesn't justify giving other politicians a free pass for saying incorrect things.
Agree, that's what it is.
Yeah, let's bring down one of the few candidates who is actually treating climate change seriously with a bunch of nitpicks. Nevermind Bernie Sanders and Elizabeth Warren wanting to shut down the entire nuclear power fleet.
I don't get the nuclear fetish. Wind and solar are already far cheaper. I'm sure you're immediately thinking "but they don't work all the time!". That's true but we're still pretty far from having enough wind/solar to turn all other power plants off even when it is windy and sunny.
Also the cost estimates of nuclear don't include decomissioning because nobody has actually decomissioned a nuclear power station yet so who knows how much it costs.
Also the cost estimates of nuclear don't include decomissioning because nobody has actually decomissioned a nuclear power station yet so who knows how much it costs.
Wind and solar are not at the scale we need to replace all the coal and gas plants. Nobody has build enough wind and solar at this scale so we don't know how much it costs to permanently maintain that setup (a lifespan of a solar panel/wind turbine is pitiful compared to nuclear).
Decommissioning costs can be considered once the planet is carbon neutral, which it is not right now. Right now the goal is to build up carbon-free energy generation. That said, if you ask the right people [1] they probably can give you an estimate.
[1] http://www.japc.co.jp/english/project/haishi/decommissioning...
Decommissioning costs can be considered once the planet is carbon neutral, which it is not right now. Right now the goal is to build up carbon-free energy generation. That said, if you ask the right people [1] they probably can give you an estimate.
[1] http://www.japc.co.jp/english/project/haishi/decommissioning...
Right now, when we make nuclear weapons from plutonium 239 and uranium 235, it looks like a regular machinist doing regular machinist things on a lathe, except they're doing the work in a glove box. These elements, their contaminants, and their decay products all decay by alpha decay, which is blocked a thin layer of basically anything. As long as it doesn't physically get inside your body, (hence the glove box) it's safe.
Uranium 233 from the thorium cycle inevitably is contaminated by uranium 232. Uranium 232 decays quickly into thallium 208, which is a hard gamma emitter. It takes a lot of work to get uranium 233 pure enough to make nuclear weapons out of it. Bodies with the resources to deal with this are already sophisticated enough to enrich uranium 235: the uranium 233 angle is irreverent.