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On December 21 2019 14:21 KwarK wrote:
The storage problems with sources like solar disappear if you treat it as a load smoothing source that allows for the higher daytime power consumption during the hot summer months. Power plants can’t easily scale up or down, they’re built to supply enough for peak consumption and overproduce at off peak times, leading to discounted electricity used for industrial electrolysis and the like at night. It’d be easier to have fewer power plants providing a lower base load with solar supplementing it during sunny days.
The problem with this is the duck curve. People tend to use the most amount of energy when they get up in the morning and when they get home in the evening, the times when solar is weak creating a duck shaped curve in the energy price gap that deepens with increased reliance on solar energy. Solar is the opposite of a load smoothing source.
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This seems like an immovable object meets an unstoppable force situation.
We're not going to miraculously figure out a way to maintain our energy consumption rates and also not cause catastrophic climate collapse, probably also not going to miraculously get westerners to act right, so whatever solution should account for both climate collapse and the social collapse that comes with it.
I have no idea on the science but it's a popular theme in a lot of post apocalyptic stuff for the nuclear plants to melt down from a lack of human maintenance/humans trying to make them work without knowing what they are doing, destroying what little habitable planet is left. Should my clan be so lucky as to survive the collapse I'd like them to not get wiped out because of hastily planned failed solutions from decades ago.
Just something to consider and you guys can carry on
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Realistically, the only way solar works outside of sunny periods is to use concentrated solar power:
https://en.wikipedia.org/wiki/Concentrated_solar_power#Costs
With the stored thermal mass, solar can generate power into the evening and in the morning peaks. It's higher cost than photovoltaics, but seems to be mostly cost competitive with traditional power sources in recent years.
Nuclear needs nation level support to work, regardless of type. In an ideal world, we'd have gen 3 reactors commercially deployed in large numbers now as a base load supplemented by solar/wind where possible, pumped storage hydroelectric dams for excess peak electricity and a lot of other pie in the sky means to replace fossil fuels, but the government incentives towards fossil fuels as well as the nuclear disasters over the last decades has stalled out the adoption of safer technologies that are designed to be human error tolerant.
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On December 20 2019 19:42 Erasme wrote:
Is it possible to be against israels treatment of the palestinian while being horrified by how china treats its minorities ?
Of course, but we're talking politically. Individually I imagine most people are horrified by both.
But it's impossible to 'isolate' China politically for this without being colossal hypocrites in the US because the US government wholeheartedly supports Israel.
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On December 21 2019 09:33 micronesia wrote:Show nested quote +On December 21 2019 06:49 Nouar wrote:On December 21 2019 04:42 micronesia wrote:On December 21 2019 04:40 Nouar wrote:On December 20 2019 20:35 micronesia wrote:
Thorium is three times as abundant as uranium and nearly as abundant as lead and gallium in the Earth's crust.[17] The Thorium Energy Alliance estimates "there is enough thorium in the United States alone to power the country at its current energy level for over 1,000 years."[16][17] "America has buried tons as a by-product of rare earth metals mining," notes Evans-Pritchard.[18] Almost all thorium is fertile Th-232, compared to uranium that is composed of 99.3% fertile U-238 and 0.7% more valuable fissile U-235.
Okay, but availability of uranium isn't really a problem for the foreseeable future. Uranium is actually pretty cheap to buy compared to the other expenses of nuclear power. It is difficult to make a practical nuclear bomb from a thorium reactor's byproducts. According to Alvin Radkowsky, designer of the world's first full-scale atomic electric power plant, "a thorium reactor's plutonium production rate would be less than 2 percent of that of a standard reactor, and the plutonium's isotopic content would make it unsuitable for a nuclear detonation."[13]:11[19] Several uranium-233 bombs have been tested, but the presence of uranium-232 tended to "poison" the uranium-233 in two ways: intense radiation from the uranium-232 made the material difficult to handle, and the uranium-232 led to possible pre-detonation. Separating the uranium-232 from the uranium-233 proved very difficult, although newer laser techniques could facilitate that process.[20][21] Thorium and non-thorium reactors both have pros and cons when it comes to nonproliferation, but I don't think one is significantly better than the other. They both produce material useful for weapons, but are difficult to use. There is much less nuclear waste—up to two orders of magnitude less, state Moir and Teller,[3] eliminating the need for large-scale or long-term storage;[13]:13 "Chinese scientists claim that hazardous waste will be a thousand times less than with uranium."[22] The radioactivity of the resulting waste also drops down to safe levels after just a one or a few hundred years, compared to tens of thousands of years needed for current nuclear waste to cool off.[23] I don't have time to do detailed research, but I think this getting taken out of context (or could just be wrong, but I'll give it the benefit of the doubt). Historically, thorium has not provided much relief when it comes to spent fuel disposal, and the industrial processes for using thorium tend to create a lot of difficult to deal with non-fuel waste. Similar to the discussion in your quote above, irradiating thorium to produce seeds of U-233 also produces an unwanted U-232 impurity which is a significant dose source. It slowly decays to radon-220 (not the isotope predominantly found in basements, i.e., radon-222) which is a gas that tends to escape its containment, but with a half life of about a minute. It then rapidly decays to progeny including an isotope of thalium that I recall releasing a significant gamma as it decays, contributing to a somewhat difficult to manage dose to workers, or the nearby public, depending on where the facility is and what type of ventilation system it has. My point being, waste considerations for thorium, as compared to traditional commercial nuclear power, are complicated and not as favorable as that article is leading you to believe. Liquid fluoride thorium reactors are designed to be meltdown proof. A plug at the bottom of the reactor melts in the event of a power failure or if temperatures exceed a set limit, draining the fuel into an underground tank for safe storage.[25]
I think they are meltdown proof because they are already in liquid form... this text doesn't really explain the actual advantages during a lose of power/cooling situation. Like the above discussion, the comparisons are actually very complicated though. I pasted the ones that I think are most relevant. The disadvantages are just engineering challenges. It is a fundamentally sound technology. Similar to how an incredible percent of atmospheric physicists agree human-induced climate change is both significant and bad, everyone who works in a field that understands what went wrong with past nuclear stuff and how new stuff compares see nuclear as a really good thing. It is very sad that some admittedly very bad things basically sidelined what should have gone on to be a major human advancement. I have nothing against thorium being a potential nuclear fuel, but most of the "advantages" being pushed are either wrong or misleading. I don't think thorium is necessarily better or worse than uranium/plutonium, just different. Yang and others exploit how complicated this topic is to make something seem better than it is. Really ? So them having absolutely no chance to explode, due to the reaction not being self-sustainable (if left unattended in case of disaster, they just shut down), is not an overwhelming advantage for you ? Nuclear waste can always be managed or buried or sent off the planet if need be. Nuclear disaster due to Chernobyl, no. Just keep that one in mind when you decide which is worth it. Modern reactors do not have a risk of nuclear explosion. At worst, hydrogen can explode and thorium does not mitigate that to my knowledge. Maybe I should rephrase Reading ahead, it seems more like you changed to an entirely different topic, but that's okay because the new topic is better. Huh? Why would there be a risk of fusion in a commercial power reactors (there wouldn't...)? Can you explain what it is about thorium, specifically, the precludes fuel meltdown and formation of corium? Addressed below. Show nested quote +Newer regular reactors like EPR work with even more temperature and pressure... Even if there are more safety measures (general "passive nuclear safety" meaning in the absence of action, it should just shut down) You seem to be confusing two separate concepts: walkaway capability from an at-power reactor without damaging the fuel via a loss of sufficient cooling post-shutdown, and inability to shut down the reactor when s*** hits the fan. Just to make sure this is perfectly clear, modern pressurized water reactors (the design I'm most familiar with and will use as an example) are able to shut down easily. When the control rods are inserted, the reactor is shut down... it takes one or two button presses, with the backup of automated protection systems (with built in coincidence and redundancy) doing it as well. Also, the coolant can be chemically poisoned if the rods can't insert for some reason. If by some chance there is a confluence of events that operators and protection systems fail to shut down the reactor, the reactor will still shut itself down. The coolant (water) doubles as the neutron moderator, and when the reactor heats, the water thermally expands, reducing the reactor's reactivity and therefore reducing power. If the water flashes to steam entirely in an extreme case, the reactor shuts down entirely due to severely insufficient neutron moderation. For this reason, the focus of the discussion should be on decay heat removal from the fuel rather than concerns about shutdown or explosions. Show nested quote +it is a lot harder to sell it to the public than a reactor working at near atmospheric pressure, negating the risk of a hydrogen explosion What does pressure have to do with the risk of hydrogen explosions? Hydrogen explosions would most likely occur in a containment following a zirc+water+heat reaction (perhaps you could show that thorium uniquely permits efficient design of reactors without use of zirc, or that uncontrolled heating events are not possible). Also, hydrogen aside, is there a technical basis you can refer to for why low-pressure reactor designs are safer? I know your point was about public perception, but there needs to be at least some reasons for why pressurization is bad... Show nested quote +. The court of public opinion is really important after the previous disasters that happened.
"Never again" worked once, will likely not work again after Fukushima. Are you referencing anything in particular with the 'never again' language? Most of the things I've been reading recently online regarding Yang's pushing of thorium, when written by people with experience in nuclear science, are underwhelming. I think part of the problem is, it's hard to separate the benefits of brand new reactor designs (which just so happen to have been designed using thorium as a fuel) with benefits that are inherent to use of thorium as a fuel.
Ok, consider me more educated than before then. When I am talking about core fusion, it is obviously not nuclear fusion aka a fusion reactor-like reaction. I chose my words poorly, I am talking about the melting (fusing in my mind) of the core, due to overheating, leading it to create corium and exit its enclosure.
You tell that it can't happen in modern reactors, but it happened (again) in Fukushima ? What generation is that reactor, and how many of them are currently functioning ? (quite a few it seems). So it looks like these are not considered as modern reactors ?
I don't believe it's specifically thorium that allows them to be corium-proof, but more the molten-salt part of it (which it looks to me is the main way to make thorium reactors, combining the benefits of both technologies). MSR have not been developed far enough to attain commercial, due to them coming too late mainly. Materials resisting corrosion is another of the issues (engineering issues that were referred to in a previous post).
Since I am a noob, allow me to present another article that looks like it is fair, is following up on some of your points, and a little bit of mine as well (even though it does not go into detail). Tell me if you have any comments on it, I'm interested.
https://whatisnuclear.com/thorium-myths.html
It says (among others) that there is technically more thorium in the crust, but a LOT more uranium in the oceans, easier to gather. Some countries like India though, with large reserves inland and no uranium, have more interest.
Some quotes :
Undenatured Thorium cycles certainly produce fewer transuranic elements (Np, Pu, Am, Cm,+), which are the major dangerous nuclides in nuclear waste in the 10,000+ year timeframe. In fact, the long-term decay heat from Thorium-MSRs can be orders of magnitude lower than that from traditional reactors. However, this same capability exists in many other reactor concepts, including U-Pu fueled fast reactors with reprocessing. So, if someone says that MSR/LFTR waste is better than traditional LWR waste, they are correct. If they say Thorium is the only game in town that can reduce waste like this, then they are not correct.
The attributes of a system that come from choosing a fluid fueled reactor include: the ability to have passive safety by draining the fuel into cooled storage tanks, online fission product removal, low/zero fabrication cost, low fissile requirement, low excess reactivity (since you refuel online) [6]
The attributes that come from choosing the Th-U fuel cycle over the U-Pu cycle include: the possibility of thermal breeding (as demonstrated in the Shippingport LWR), the reduced production of minor actinides (see Misconception #5), allowing nuclear waste to be safer without aggressive reprocessing, and the ability to use the Thorium mineral base instead of the Uranium minerals (useful if your country has Th but no U. See Misconception #4).
(The combination looks really interesting)
Having low-pressure coolant is what gives the MSR its safety advantage, dude. SFR, LFR, FHR, etc. are other reactors that can do this with or without Thorium.
About the pressure issue and explosion, I am not knowledgeable enough to go into the technical details. However, neither is the public opinion. In this court, the damage of any explosion is increased by pressure (gas tanks etc).
I'd be interested if you could further your reasoning on that. I believed Corium creation is one of the main reason of explosion (steam and hydrogen creation in a confined area), so even though it's not directly linked pressure/explosion, it's still related ?
Wikipedia also tells about PWR :
The coolant water must be highly pressurized to remain liquid at high temperatures. This requires high strength piping and a heavy pressure vessel and hence increases construction costs. The higher pressure can increase the consequences of a loss-of-coolant accident.
Currently, the public opinion on next-gen pressurised reactors like the EPR (in France, but we love to complain about everything) is extremely bad (due to fears of insecurity based on pressure, and also the multiple delays and budget issues). We also had an extremely bad view of Superphenix, which was a breeder reactor, despite its advantages.
Even if current-gen PWR or others are safe, it's very hard to sell that, when "uranium reactors" failed twice (I am generalising on purpose).
In this event, another technology entirely, might prove to be more acceptable to the public, even if it's not correct technically speaking.
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Ever since the Fukushima disaster it's hard to imagine a government that relies on public opinion to be able to build nuclear generation, the advantages of thorium reactors or not. The French manage to do it somehow, though in their case it is tied up in pride of being a nuclear power. Memories will have to fade of Fukushima or a major energy crisis will have to occur. Unlikely as long as LNG seems to be cheap and supply reliable. The choice for the future however is between nuclear and renewables. I thought power storage problems have been solved long ago and USA is blessed with plenty of uninhabited land and sunlight, as well as an industrial base. I would had though solar energy would be an obvious choice for USA over nuclear power.
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Am I the only person that didn't know Trump raised the smoking (or more importantly) vaping age to 21?
Both parties really want to energize the youth vote to kick their asses out don't they?
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Why would you care about the youth vote? The youth don't vote, over 50s do.
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On December 21 2019 21:34 Dangermousecatdog wrote:
Why would you care about the youth vote? The youth don't vote, over 50s do.
They found out the olds are going to leave them a ecological and economic hellscape long before they have any real control, so they are a bit more motivated this election.
Sanders volunteer efforts numbers show they are basically off the charts this election. He's got 25,000+ volunteers just in Iowa. For context, about 175k total participated in the 2016 caucus.
(EDIT: Sanders campaign had already contacted 1,000,000 people in Iowa back in September as well)
Though likely because of Iowa's new caucus system there will be a lot more elderly and rural votes (which tend to be more conservative).
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What age range is the youth group for you?
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United States24578 Posts
On December 21 2019 21:13 Nouar wrote:Show nested quote +On December 21 2019 09:33 micronesia wrote:On December 21 2019 06:49 Nouar wrote:On December 21 2019 04:42 micronesia wrote:On December 21 2019 04:40 Nouar wrote:On December 20 2019 20:35 micronesia wrote:
Thorium is three times as abundant as uranium and nearly as abundant as lead and gallium in the Earth's crust.[17] The Thorium Energy Alliance estimates "there is enough thorium in the United States alone to power the country at its current energy level for over 1,000 years."[16][17] "America has buried tons as a by-product of rare earth metals mining," notes Evans-Pritchard.[18] Almost all thorium is fertile Th-232, compared to uranium that is composed of 99.3% fertile U-238 and 0.7% more valuable fissile U-235.
Okay, but availability of uranium isn't really a problem for the foreseeable future. Uranium is actually pretty cheap to buy compared to the other expenses of nuclear power. It is difficult to make a practical nuclear bomb from a thorium reactor's byproducts. According to Alvin Radkowsky, designer of the world's first full-scale atomic electric power plant, "a thorium reactor's plutonium production rate would be less than 2 percent of that of a standard reactor, and the plutonium's isotopic content would make it unsuitable for a nuclear detonation."[13]:11[19] Several uranium-233 bombs have been tested, but the presence of uranium-232 tended to "poison" the uranium-233 in two ways: intense radiation from the uranium-232 made the material difficult to handle, and the uranium-232 led to possible pre-detonation. Separating the uranium-232 from the uranium-233 proved very difficult, although newer laser techniques could facilitate that process.[20][21] Thorium and non-thorium reactors both have pros and cons when it comes to nonproliferation, but I don't think one is significantly better than the other. They both produce material useful for weapons, but are difficult to use. There is much less nuclear waste—up to two orders of magnitude less, state Moir and Teller,[3] eliminating the need for large-scale or long-term storage;[13]:13 "Chinese scientists claim that hazardous waste will be a thousand times less than with uranium."[22] The radioactivity of the resulting waste also drops down to safe levels after just a one or a few hundred years, compared to tens of thousands of years needed for current nuclear waste to cool off.[23] I don't have time to do detailed research, but I think this getting taken out of context (or could just be wrong, but I'll give it the benefit of the doubt). Historically, thorium has not provided much relief when it comes to spent fuel disposal, and the industrial processes for using thorium tend to create a lot of difficult to deal with non-fuel waste. Similar to the discussion in your quote above, irradiating thorium to produce seeds of U-233 also produces an unwanted U-232 impurity which is a significant dose source. It slowly decays to radon-220 (not the isotope predominantly found in basements, i.e., radon-222) which is a gas that tends to escape its containment, but with a half life of about a minute. It then rapidly decays to progeny including an isotope of thalium that I recall releasing a significant gamma as it decays, contributing to a somewhat difficult to manage dose to workers, or the nearby public, depending on where the facility is and what type of ventilation system it has. My point being, waste considerations for thorium, as compared to traditional commercial nuclear power, are complicated and not as favorable as that article is leading you to believe. Liquid fluoride thorium reactors are designed to be meltdown proof. A plug at the bottom of the reactor melts in the event of a power failure or if temperatures exceed a set limit, draining the fuel into an underground tank for safe storage.[25]
I think they are meltdown proof because they are already in liquid form... this text doesn't really explain the actual advantages during a lose of power/cooling situation. Like the above discussion, the comparisons are actually very complicated though. I pasted the ones that I think are most relevant. The disadvantages are just engineering challenges. It is a fundamentally sound technology. Similar to how an incredible percent of atmospheric physicists agree human-induced climate change is both significant and bad, everyone who works in a field that understands what went wrong with past nuclear stuff and how new stuff compares see nuclear as a really good thing. It is very sad that some admittedly very bad things basically sidelined what should have gone on to be a major human advancement. I have nothing against thorium being a potential nuclear fuel, but most of the "advantages" being pushed are either wrong or misleading. I don't think thorium is necessarily better or worse than uranium/plutonium, just different. Yang and others exploit how complicated this topic is to make something seem better than it is. Really ? So them having absolutely no chance to explode, due to the reaction not being self-sustainable (if left unattended in case of disaster, they just shut down), is not an overwhelming advantage for you ? Nuclear waste can always be managed or buried or sent off the planet if need be. Nuclear disaster due to Chernobyl, no. Just keep that one in mind when you decide which is worth it. Modern reactors do not have a risk of nuclear explosion. At worst, hydrogen can explode and thorium does not mitigate that to my knowledge. Maybe I should rephrase Reading ahead, it seems more like you changed to an entirely different topic, but that's okay because the new topic is better. there is no risk of core fusion Huh? Why would there be a risk of fusion in a commercial power reactors (there wouldn't...)? meltdown, or corium formation Can you explain what it is about thorium, specifically, the precludes fuel meltdown and formation of corium? in addition to hydrogen explosion Addressed below. Newer regular reactors like EPR work with even more temperature and pressure... Even if there are more safety measures (general "passive nuclear safety" meaning in the absence of action, it should just shut down) You seem to be confusing two separate concepts: walkaway capability from an at-power reactor without damaging the fuel via a loss of sufficient cooling post-shutdown, and inability to shut down the reactor when s*** hits the fan. Just to make sure this is perfectly clear, modern pressurized water reactors (the design I'm most familiar with and will use as an example) are able to shut down easily. When the control rods are inserted, the reactor is shut down... it takes one or two button presses, with the backup of automated protection systems (with built in coincidence and redundancy) doing it as well. Also, the coolant can be chemically poisoned if the rods can't insert for some reason. If by some chance there is a confluence of events that operators and protection systems fail to shut down the reactor, the reactor will still shut itself down. The coolant (water) doubles as the neutron moderator, and when the reactor heats, the water thermally expands, reducing the reactor's reactivity and therefore reducing power. If the water flashes to steam entirely in an extreme case, the reactor shuts down entirely due to severely insufficient neutron moderation. For this reason, the focus of the discussion should be on decay heat removal from the fuel rather than concerns about shutdown or explosions. it is a lot harder to sell it to the public than a reactor working at near atmospheric pressure, negating the risk of a hydrogen explosion What does pressure have to do with the risk of hydrogen explosions? Hydrogen explosions would most likely occur in a containment following a zirc+water+heat reaction (perhaps you could show that thorium uniquely permits efficient design of reactors without use of zirc, or that uncontrolled heating events are not possible). Also, hydrogen aside, is there a technical basis you can refer to for why low-pressure reactor designs are safer? I know your point was about public perception, but there needs to be at least some reasons for why pressurization is bad... . The court of public opinion is really important after the previous disasters that happened.
"Never again" worked once, will likely not work again after Fukushima. Are you referencing anything in particular with the 'never again' language? Most of the things I've been reading recently online regarding Yang's pushing of thorium, when written by people with experience in nuclear science, are underwhelming. I think part of the problem is, it's hard to separate the benefits of brand new reactor designs (which just so happen to have been designed using thorium as a fuel) with benefits that are inherent to use of thorium as a fuel. Ok, consider me more educated than before then. When I am talking about core fusion, it is obviously not nuclear fusion aka a fusion reactor-like reaction. I chose my words poorly, I am talking about the melting (fusing in my mind) of the core, due to overheating, leading it to create corium and exit its enclosure. You tell that it can't happen in modern reactors, but it happened (again) in Fukushima ? What generation is that reactor, and how many of them are currently functioning ? ( quite a few it seems). So it looks like these are not considered as modern reactors ?
It is time for me to blow your mind. I did not say that meltdown cannot happen with modern reactors.
That is one of the reasons why all commercial power plants need to perform considerable emergency planning.
I don't believe it's specifically thorium that allows them to be corium-proof, but more the molten-salt part of it (which it looks to me is the main way to make thorium reactors, combining the benefits of both technologies). MSR have not been developed far enough to attain commercial, due to them coming too late mainly. Materials resisting corrosion is another of the issues (engineering issues that were referred to in a previous post).
I have nothing against more development of alternative coolants. Hell, the navy used liquid sodium (metal) cooling in their second design in the 1950s (if you can use sodium metal as a coolant in a vessel that travels through the water, you can probably do just about anything). Corrosion has been a frontier of improvement for water-based reactors and is certainly important, but is not likely to contribute to meltdowns. Reactor plant designs are analyzed for failure of all the limiting materials and cooling can be maintained in all but the most extreme and unlikely scenarios, the compounding of multiple unlikely events alongside corrosion that went undetected. Of course, corrosion is carefully monitored.
Since I am a noob, allow me to present another article that looks like it is fair, is following up on some of your points, and a little bit of mine as well (even though it does not go into detail). Tell me if you have any comments on it, I'm interested. https://whatisnuclear.com/thorium-myths.htmlIt says (among others) that there is technically more thorium in the crust, but a LOT more uranium in the oceans, easier to gather. Some countries like India though, with large reserves inland and no uranium, have more interest. Some quotes : Show nested quote +Undenatured Thorium cycles certainly produce fewer transuranic elements (Np, Pu, Am, Cm,+), which are the major dangerous nuclides in nuclear waste in the 10,000+ year timeframe. In fact, the long-term decay heat from Thorium-MSRs can be orders of magnitude lower than that from traditional reactors. However, this same capability exists in many other reactor concepts, including U-Pu fueled fast reactors with reprocessing. So, if someone says that MSR/LFTR waste is better than traditional LWR waste, they are correct. If they say Thorium is the only game in town that can reduce waste like this, then they are not correct. Show nested quote +The attributes of a system that come from choosing a fluid fueled reactor include: the ability to have passive safety by draining the fuel into cooled storage tanks, online fission product removal, low/zero fabrication cost, low fissile requirement, low excess reactivity (since you refuel online) [6]
The attributes that come from choosing the Th-U fuel cycle over the U-Pu cycle include: the possibility of thermal breeding (as demonstrated in the Shippingport LWR), the reduced production of minor actinides (see Misconception #5), allowing nuclear waste to be safer without aggressive reprocessing, and the ability to use the Thorium mineral base instead of the Uranium minerals (useful if your country has Th but no U. See Misconception #4). (The combination looks really interesting) Show nested quote +Having low-pressure coolant is what gives the MSR its safety advantage, dude. SFR, LFR, FHR, etc. are other reactors that can do this with or without Thorium. About the pressure issue and explosion, I am not knowledgeable enough to go into the technical details. However, neither is the public opinion. In this court, the damage of any explosion is increased by pressure (gas tanks etc). I'd be interested if you could further your reasoning on that. I believed Corium creation is one of the main reason of explosion (steam and hydrogen creation in a confined area), so even though it's not directly linked pressure/explosion, it's still related ? Wikipedia also tells about PWR : Show nested quote +The coolant water must be highly pressurized to remain liquid at high temperatures. This requires high strength piping and a heavy pressure vessel and hence increases construction costs. The higher pressure can increase the consequences of a loss-of-coolant accident. Currently, the public opinion on next-gen pressurised reactors like the EPR (in France, but we love to complain about everything) is extremely bad (due to fears of insecurity based on pressure, and also the multiple delays and budget issues). We also had an extremely bad view of Superphenix, which was a breeder reactor, despite its advantages. Even if current-gen PWR or others are safe, it's very hard to sell that, when "uranium reactors" failed twice (I am generalising on purpose). In this event, another technology entirely, might prove to be more acceptable to the public, even if it's not correct technically speaking.
As for the specific discussion about pressurization (which is getting away from thorium vs uranium), having a highly pressurized primary loop does have some drawbacks, but that is mostly divorced from the earlier discussion about explosions. How violently coolant exist the primary loop during a major breach doesn't really matter to anyone except for any workers who may have been inside the containment when it happened. The containment will capture the steam. In summary, steam explosions are much different than hydrogen explosions, which are much different than nuclear explosions (which only Chernobyl could come close to qualifying as, and even that is a bit unclear). Three Mile Island would not qualify as an explosion of any of those three types, yet partially melted down the fuel. Fukushima was multiple hydrogen explosions within the containment buildings. Chernobyl was a runaway criticality and explosion due to a combination of poor design and poor operation, the former of which was engineered out by rivals decades earlier.
The formation of corium is literally just the melting down of solid fuel to a liquid/lava due to insufficient cooling for whatever reason. It is separate from any explosions. In a modern pressurized water reactor, for core meltdown to occur, there needs to be a severe loss of water cooling to the fuel. The standing water in the reactor vessel will boil away, exposing the fuel to the air or other voids.
One parting thought: What's the difference between corium formed from the meltdown of a core, and a liquid fuel system?
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On December 21 2019 21:52 GreenHorizons wrote:Show nested quote +On December 21 2019 21:34 Dangermousecatdog wrote:
Why would you care about the youth vote? The youth don't vote, over 50s do. They found out the olds are going to leave them a ecological and economic hellscape long before they have any real control, so they are a bit more motivated this election. Sanders volunteer efforts numbers show they are basically off the charts this election. He's got 25,000+ volunteers just in Iowa. For context, about 175k total participated in the 2016 caucus. (EDIT: Sanders campaign had already contacted 1,000,000 people in Iowa back in September as well) Though likely because of Iowa's new caucus system there will be a lot more elderly and rural votes (which tend to be more conservative).
Didn't help us in 2016.
Granted, crappy candidate, but I'm still not convinced that youth voters will be a long-term factor. I'll need to see it more consistently before I believe it.
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On December 21 2019 21:28 GreenHorizons wrote:
Am I the only person that didn't know Trump raised the smoking (or more importantly) vaping age to 21?
Both parties really want to energize the youth vote to kick their asses out don't they?
I see no reason why this ought to be an issue. The legal age of e-cigs should correspond. With cigarettes, and maybe it'll stop the marketing tailored to kids.
But that's me being a hopeless optimist. It won't change much.
On December 21 2019 23:45 Stratos_speAr wrote:Show nested quote +On December 21 2019 21:52 GreenHorizons wrote:On December 21 2019 21:34 Dangermousecatdog wrote:
Why would you care about the youth vote? The youth don't vote, over 50s do. They found out the olds are going to leave them a ecological and economic hellscape long before they have any real control, so they are a bit more motivated this election. Sanders volunteer efforts numbers show they are basically off the charts this election. He's got 25,000+ volunteers just in Iowa. For context, about 175k total participated in the 2016 caucus. (EDIT: Sanders campaign had already contacted 1,000,000 people in Iowa back in September as well) Though likely because of Iowa's new caucus system there will be a lot more elderly and rural votes (which tend to be more conservative). Didn't help us in 2016. Granted, crappy candidate, but I'm still not convinced that youth voters will be a long-term factor. I'll need to see it more consistently before I believe it.
Volunteer turnout in 2016 from youth was low; when I canvassed in Pennsylvania in 2016, I was driving mostly old retired ladies over from Maryland to help out. I was the youngest one there.
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On December 21 2019 23:15 Dangermousecatdog wrote:
What age range is the youth group for you?
The large umbrella would be under 50, but climate, guns, and working poverty has been driving growing movements across the country in the under 35 demo, and most unusually, people 17-23 (and younger, but they're just fucked).
That said only Sanders brings them out, no one else. I say anyone other than Sanders is a sure loss and even Sanders doesn't guarantee victory, just that if he win's it isn't entirely Pyrrhic.
On December 21 2019 23:57 Lord Tolkien wrote:Show nested quote +On December 21 2019 21:28 GreenHorizons wrote:
Am I the only person that didn't know Trump raised the smoking (or more importantly) vaping age to 21?
Both parties really want to energize the youth vote to kick their asses out don't they? I see no reason why this ought to be an issue. The legal age of e-cigs should correspond. With cigarettes, and maybe it'll stop the marketing tailored to kids. But that's me being a hopeless optimist. It won't change much.
Kids love their vapin and hate old people telling them what to do though. Then there's the whole we'll give em a rocket launcher and send them half way around the world to get their limbs blown off and then deny them the ability to smoke a cigarette because they aren't responsible enough to make that decision for themselves.
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On December 21 2019 23:43 micronesia wrote:
The formation of corium is literally just the melting down of solid fuel to a liquid/lava due to insufficient cooling for whatever reason. It is separate from any explosions. In a modern pressurized water reactor, for core meltdown to occur, there needs to be a severe loss of water cooling to the fuel. The standing water in the reactor vessel will boil away, exposing the fuel to the air or other voids.
One parting thought: What's the difference between corium formed from the meltdown of a core, and a liquid fuel system?
It seemed to me that the meltdown and corium itself was directly responsible for hydrogen creation, or am I interpreting too much ?
Corium composition and reactions
The composition of corium depends on the design type of the reactor, and specifically on the materials used in the control rods, coolant and reactor vessel structural materials. There are differences between pressurized water reactor (PWR) and boiling water reactor (BWR) coriums.
In contact with water, hot boron carbide from BWR reactor control rods forms first boron oxide and methane, then boric acid. Boron may also continue to contribute to reactions by the boric acid in an emergency coolant.
Zirconium from zircaloy, together with other metals, reacts with water and produces zirconium dioxide and hydrogen. The production of hydrogen is a major danger in reactor accidents.
During a meltdown, the temperature of the fuel rods increases and they can deform, in the case of zircaloy cladding, above 700–900 °C (1,292–1,652 °F). If the reactor pressure is low, the pressure inside the fuel rods ruptures the control rod cladding. High-pressure conditions push the cladding onto the fuel pellets, promoting formation of uranium dioxide–zirconium eutectic with a melting point of 1,200–1,400 °C (2,190–2,550 °F). An exothermic reaction occurs between steam and zirconium, which may produce enough heat to be self-sustaining without the contribution of decay heat from radioactivity. Hydrogen is released in an amount of about 0.5 m3 (18 cu ft) of hydrogen (at normal temperature/pressure) per kilogram of zircaloy oxidized.
The temperature of corium can be as high as 2,400 °C (4,350 °F) in the first hours after the meltdown, potentially reaching over 2,800 °C (5,070 °F). A large amount of heat can be released by reaction of metals (particularly zirconium) in corium with water. Flooding of the corium mass with water, or the drop of molten corium mass into a water pool, may result in a temperature spike and production of large amounts of hydrogen, which can result in a pressure spike in the containment vessel. The steam explosion resulting from such sudden corium-water contact can disperse the materials and form projectiles that may damage the containment vessel by impact. Subsequent pressure spikes can be caused by combustion of the released hydrogen. Detonation risks can be reduced by the use of catalytic hydrogen recombiners.[4]
As to your last question, I don't really get the catch. A temperature-controlled of fuel versus an uncontrolled, fused mass of melted stuff that should not be that way, producing all sorts of dangerous, explosive or highly corrosive material ?
They don't look comparable at first glance.
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United States24578 Posts
On December 22 2019 00:51 Nouar wrote:Show nested quote +On December 21 2019 23:43 micronesia wrote:
The formation of corium is literally just the melting down of solid fuel to a liquid/lava due to insufficient cooling for whatever reason. It is separate from any explosions. In a modern pressurized water reactor, for core meltdown to occur, there needs to be a severe loss of water cooling to the fuel. The standing water in the reactor vessel will boil away, exposing the fuel to the air or other voids.
One parting thought: What's the difference between corium formed from the meltdown of a core, and a liquid fuel system?
It seemed to me that the meltdown and corium itself was directly responsible for hydrogen creation, or am I interpreting too much ? Show nested quote +Corium composition and reactions
The composition of corium depends on the design type of the reactor, and specifically on the materials used in the control rods, coolant and reactor vessel structural materials. There are differences between pressurized water reactor (PWR) and boiling water reactor (BWR) coriums.
In contact with water, hot boron carbide from BWR reactor control rods forms first boron oxide and methane, then boric acid. Boron may also continue to contribute to reactions by the boric acid in an emergency coolant.
Zirconium from zircaloy, together with other metals, reacts with water and produces zirconium dioxide and hydrogen. The production of hydrogen is a major danger in reactor accidents. Show nested quote +During a meltdown, the temperature of the fuel rods increases and they can deform, in the case of zircaloy cladding, above 700–900 °C (1,292–1,652 °F). If the reactor pressure is low, the pressure inside the fuel rods ruptures the control rod cladding. High-pressure conditions push the cladding onto the fuel pellets, promoting formation of uranium dioxide–zirconium eutectic with a melting point of 1,200–1,400 °C (2,190–2,550 °F). An exothermic reaction occurs between steam and zirconium, which may produce enough heat to be self-sustaining without the contribution of decay heat from radioactivity. Hydrogen is released in an amount of about 0.5 m3 (18 cu ft) of hydrogen (at normal temperature/pressure) per kilogram of zircaloy oxidized. Show nested quote +The temperature of corium can be as high as 2,400 °C (4,350 °F) in the first hours after the meltdown, potentially reaching over 2,800 °C (5,070 °F). A large amount of heat can be released by reaction of metals (particularly zirconium) in corium with water. Flooding of the corium mass with water, or the drop of molten corium mass into a water pool, may result in a temperature spike and production of large amounts of hydrogen, which can result in a pressure spike in the containment vessel. The steam explosion resulting from such sudden corium-water contact can disperse the materials and form projectiles that may damage the containment vessel by impact. Subsequent pressure spikes can be caused by combustion of the released hydrogen. Detonation risks can be reduced by the use of catalytic hydrogen recombiners.[4] As to your last question, I don't really get the catch. A temperature-controlled of fuel versus an uncontrolled, fused mass of melted stuff that should not be that way, producing all sorts of dangerous, explosive or highly corrosive material ? They don't look comparable at first glance.
Excess hydrogen formation (a prerequisite for hydrogen explosions in the containment) comes from the combination of zirc, water, and excess heat. That is related to the formation of corium, but they are two different things that shouldn't be lumped together, otherwise you can't explain why Three Mile Island melted fuel and had no hydrogen explosion.
My point about corium vs liquid fuel is basically that you aren't making an apples to apples comparison. Corium is solid fuel that melted, combined with non-fuel material that also melted most likely, and then ends up where it shouldn't be... a place where you can't cool it properly. Liquid fuel systems as you described have backups that allow the fuel to "go somewhere" where it can be more easily kept cool in the event of an emergency. What would happen if the liquid fuel ended up where it wasn't supposed to? What would happen if corium ended up in the place where you normally put liquid fuel to cool in an emergency? The issue is with the emergency cooling system, not the fuel system itself. One exception is that formation of corium involve melting and entraining of zirc which can make the cooling requirements more strict than for liquid fuel emergency cooling which presumably made it to its emergency cooling equipment prior to overheating to the point where it takes structural materials with it.
Really what I'm getting at is most generalizations in this discussion have been category errors.
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On December 21 2019 23:58 GreenHorizons wrote:Show nested quote +On December 21 2019 23:15 Dangermousecatdog wrote:
What age range is the youth group for you? The large umbrella would be under 50, but climate, guns, and working poverty has been driving growing movements across the country in the under 35 demo, and most unusually, people 17-23 (and younger, but they're just fucked). That said only Sanders brings them out, no one else. I say anyone other than Sanders is a sure loss and even Sanders doesn't guarantee victory, just that if he win's it isn't entirely Pyrrhic. Show nested quote +On December 21 2019 23:57 Lord Tolkien wrote:On December 21 2019 21:28 GreenHorizons wrote:
Am I the only person that didn't know Trump raised the smoking (or more importantly) vaping age to 21?
Both parties really want to energize the youth vote to kick their asses out don't they? I see no reason why this ought to be an issue. The legal age of e-cigs should correspond. With cigarettes, and maybe it'll stop the marketing tailored to kids. But that's me being a hopeless optimist. It won't change much. Kids love their vapin and hate old people telling them what to do though. Then there's the whole we'll give em a rocket launcher and send them half way around the world to get their limbs blown off and then deny them the ability to smoke a cigarette because they aren't responsible enough to make that decision for themselves.
Under 50 is exceptionally optimistic to be called youth. A case of GH operating under terms that is separate from commonly defined terms. I'm sure there are many people happy to be counted as youth at the age of 49. Whatever you choose to call youth, is a lesser population, so it's no suprise if they aren't a targetted group.
In any case, smoking and vaping and their products needs to be regulated more. On a scale of 0-10 of terrible things Trump may or may not have done, this rates as 0.
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On December 21 2019 21:23 Dangermousecatdog wrote:
Ever since the Fukushima disaster it's hard to imagine a government that relies on public opinion to be able to build nuclear generation, the advantages of thorium reactors or not. The French manage to do it somehow, though in their case it is tied up in pride of being a nuclear power. Memories will have to fade of Fukushima or a major energy crisis will have to occur. Unlikely as long as LNG seems to be cheap and supply reliable. The choice for the future however is between nuclear and renewables. I thought power storage problems have been solved long ago and USA is blessed with plenty of uninhabited land and sunlight, as well as an industrial base. I would had though solar energy would be an obvious choice for USA over nuclear power.
Some people would argue that fukushima actually showed how safe it was. That big of a disaster hitting a nuclear plant and only 100~deaths so far related to radiations.
Sadly even in France people are turning away for the nuclear energy.
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On December 22 2019 00:51 Nouar wrote:Show nested quote +On December 21 2019 23:43 micronesia wrote:
The formation of corium is literally just the melting down of solid fuel to a liquid/lava due to insufficient cooling for whatever reason. It is separate from any explosions. In a modern pressurized water reactor, for core meltdown to occur, there needs to be a severe loss of water cooling to the fuel. The standing water in the reactor vessel will boil away, exposing the fuel to the air or other voids.
One parting thought: What's the difference between corium formed from the meltdown of a core, and a liquid fuel system?
It seemed to me that the meltdown and corium itself was directly responsible for hydrogen creation, or am I interpreting too much ? Show nested quote +Corium composition and reactions
The composition of corium depends on the design type of the reactor, and specifically on the materials used in the control rods, coolant and reactor vessel structural materials. There are differences between pressurized water reactor (PWR) and boiling water reactor (BWR) coriums.
In contact with water, hot boron carbide from BWR reactor control rods forms first boron oxide and methane, then boric acid. Boron may also continue to contribute to reactions by the boric acid in an emergency coolant.
Zirconium from zircaloy, together with other metals, reacts with water and produces zirconium dioxide and hydrogen. The production of hydrogen is a major danger in reactor accidents. Show nested quote +During a meltdown, the temperature of the fuel rods increases and they can deform, in the case of zircaloy cladding, above 700–900 °C (1,292–1,652 °F). If the reactor pressure is low, the pressure inside the fuel rods ruptures the control rod cladding. High-pressure conditions push the cladding onto the fuel pellets, promoting formation of uranium dioxide–zirconium eutectic with a melting point of 1,200–1,400 °C (2,190–2,550 °F). An exothermic reaction occurs between steam and zirconium, which may produce enough heat to be self-sustaining without the contribution of decay heat from radioactivity. Hydrogen is released in an amount of about 0.5 m3 (18 cu ft) of hydrogen (at normal temperature/pressure) per kilogram of zircaloy oxidized. Show nested quote +The temperature of corium can be as high as 2,400 °C (4,350 °F) in the first hours after the meltdown, potentially reaching over 2,800 °C (5,070 °F). A large amount of heat can be released by reaction of metals (particularly zirconium) in corium with water. Flooding of the corium mass with water, or the drop of molten corium mass into a water pool, may result in a temperature spike and production of large amounts of hydrogen, which can result in a pressure spike in the containment vessel. The steam explosion resulting from such sudden corium-water contact can disperse the materials and form projectiles that may damage the containment vessel by impact. Subsequent pressure spikes can be caused by combustion of the released hydrogen. Detonation risks can be reduced by the use of catalytic hydrogen recombiners.[4] As to your last question, I don't really get the catch. A temperature-controlled of fuel versus an uncontrolled, fused mass of melted stuff that should not be that way, producing all sorts of dangerous, explosive or highly corrosive material ? They don't look comparable at first glance.
Dumping the superhot stuff into water does not work as layman might expect. Especially with metals due to their high heat capacity. The water around superhot object turns to gas extremly fast as a result creating a bubble of steam, hydrogen and oxygen thus separating the object from the water, effectievly cutting the heat exchange for a short time. The local pressure rises extremly fast and as result the object (if it is not heavy enough) might be turned into projectile or if its not sturdy enough it my fragment and those fragments becomes projectiles.
Just in case You wonder where the hydrogen/steam/temperature spike comes from in this scenario.
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On December 22 2019 01:29 Dangermousecatdog wrote:Show nested quote +On December 21 2019 23:58 GreenHorizons wrote:On December 21 2019 23:15 Dangermousecatdog wrote:
What age range is the youth group for you? The large umbrella would be under 50, but climate, guns, and working poverty has been driving growing movements across the country in the under 35 demo, and most unusually, people 17-23 (and younger, but they're just fucked). That said only Sanders brings them out, no one else. I say anyone other than Sanders is a sure loss and even Sanders doesn't guarantee victory, just that if he win's it isn't entirely Pyrrhic. On December 21 2019 23:57 Lord Tolkien wrote:On December 21 2019 21:28 GreenHorizons wrote:
Am I the only person that didn't know Trump raised the smoking (or more importantly) vaping age to 21?
Both parties really want to energize the youth vote to kick their asses out don't they? I see no reason why this ought to be an issue. The legal age of e-cigs should correspond. With cigarettes, and maybe it'll stop the marketing tailored to kids. But that's me being a hopeless optimist. It won't change much. Kids love their vapin and hate old people telling them what to do though. Then there's the whole we'll give em a rocket launcher and send them half way around the world to get their limbs blown off and then deny them the ability to smoke a cigarette because they aren't responsible enough to make that decision for themselves. Under 50 is exceptionally optimistic to be called youth. A case of GH operating under terms that is separate from commonly defined terms. I'm sure there are many people happy to be counted as youth at the age of 49. Whatever you choose to call youth, is a lesser population, so it's no suprise if they aren't a targetted group. In any case, smoking and vaping and their products needs to be regulated more. On a scale of 0-10 of terrible things Trump may or may not have done, this rates as 0.
+ Show Spoiler +I wouldn't use the term youth to specifically identify them but "younger voters" as opposed to the over 50 crowd which describe "older voters", which is notoriously more reliable to vote. 35-45 is typically where the cutoff is somewhat arbitrarily placed depending on who is talking about it.
Youth is typically the current/newest voting generation but with Z coming of age this election it puts millennials in a grey area for a bit.
As someone who regularly points out the horrific stuff Trump and the US government in general does, obviously I didn't think this was some egregiously terrible action lol?
The point was it's the kinda thing that pisses off people 17-20. That they can sign-up to die for the military industrial complex specifically to avoid crushing poverty, but people insist they don't have the capacity to make a choice about smoking a cigarette and must be protected by law from even seeing them promoted.
Surely banning the advertisement to and recruiting of 17-20 year olds should be banned for the military too?
If they can't smoke a cigarette on their break at their shitty wage-slave job, the military shouldn't be able to try to bait them into killing brown people half way around the planet so they can (maybe) have a (probably hazardous) place to live when they get back.
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EPT
