The Shidaowan plant, a demonstration high-temperature, gas-cooled reactor with a pebble-bed module (HTR-PM), went into commercial operation last December.
...
Researchers at Tsinghua University in China performed two safety tests on the Shidaowan plant’s reactor modules by shutting off active power supply to see if the decay heat could be removed passively. The responses of temperatures and nuclear power in each unit confirmed that they can be cooled down naturally, without active intervention.
Comment box Scope: personal reaction to content Tone: interested but not convinced Opinion: yes Sarcasm/humor: yes Pretty cool tech but the US government sold all its helium in 1996. I hope that...
Comment box
Scope: personal reaction to content
Tone: interested but not convinced
Opinion: yes
Sarcasm/humor: yes
Pretty cool tech but the US government sold all its helium in 1996. I hope that "a small amount of helium gas" is actually a small amount. I understand it to be in contention for uses in MRIs and other important things already. Natural gas extraction and by extension helium extraction is not super enviro friendly (methane leaks contribute a lot to emissions, and probably more than we realize), and IDK where we will get it if not from underground gas, which we are trying to get off of. I looked up the nuclear supply chain and it already looks a bit rough. Hopefully this can be solved.
This setup makes such a reactor “meltdown proof,” in concept.
Does anyone here have enough knowledge to challenge this? What is the catch? I support the use of nuclear energy instead of fossil fuels, but I am also trying to be realistic. Are we serious about a claim of "meltdown proof"? What about if the reactor is hit by an earthquake and tsunami?? Unlikely yeah. But catastrophic, as we already know.
I don't need convincing about nuclear's safety record, I've seen all the charts about air pollution from coal and gas. But I cannot tell marketing hype from reality with this industry. Is this passive safety fix something I can reasonably tell my nuclear-skeptic mother in law at Christmas dinner?
The wikipedia article on pebble-bed reactors has a good section on why they're much safer than the older designs your mom is thinking of, specifically the section on safety. But in general, the...
The wikipedia article on pebble-bed reactors has a good section on why they're much safer than the older designs your mom is thinking of, specifically the section on safety.
But in general, the heat is transferred away from the pebbles using an inert, fireproof gas which won't condense out, the pebbles are physically stable at higher temperatures than they can generate, and the container they're held in won't melt at the stable/uncontrolled temperature. So the worst that happens without power or human intervention is that it gets hot and sits there. I wouldn't go up and lick it, but it's not going to pollute the region.
Being meltdown proof isn’t all that rare for modern nuclear reactor designs. The benefit of pebble reactors is the simplicity in their cooling system. As we all know, the more complex, the more...
Being meltdown proof isn’t all that rare for modern nuclear reactor designs. The benefit of pebble reactors is the simplicity in their cooling system. As we all know, the more complex, the more things can go wrong.
In terms of natural disasters, one issue is that if oxygen enters the core it can cause the graphite to ignite due to the high temperatures it runs at.
It is funny to me that helium is basically a finite non-renewable resource that is incredibly important for tons of industrial and medical applications and we still just use it to fill up balloons...
It is funny to me that helium is basically a finite non-renewable resource that is incredibly important for tons of industrial and medical applications and we still just use it to fill up balloons so they float.
I remember hearing about how we were running out of helium and thought that was kind of strange. Then the news cycle was all about how we're not running out of regular helium and there will be...
I remember hearing about how we were running out of helium and thought that was kind of strange. Then the news cycle was all about how we're not running out of regular helium and there will be plenty of balloons for parties.
I never followed up until now, but there's a really interesting explanation of different helium grades on this company's site, as well as who buys what grades (semi-conductor manufacturers, cryolabs, scuba, military, and balloon salespersons). Crazy! I bet balloons make up most of the cubic volume of helium sales though!
Interesting, didn't know the difference between balloons and an MRI is only .0095% purity, I wouldn't have thought it would make that big of a difference. Is it really difficult to refine Grade...
Interesting, didn't know the difference between balloons and an MRI is only .0095% purity, I wouldn't have thought it would make that big of a difference. Is it really difficult to refine Grade 4.5 to Grade 5? It says that Grade 4.5 (for balloons) also can be used push gas in MRI applications, so I guess it still could have some medical purpose.
"Liquid helium is inherently extremely pure — far more pure than even Grade 5 helium actually, and liquid is the most efficient way to move product. Therefore, for helium suppliers to purposely offer a lower grade helium, they would actually have to add new operational methods and separate processes and transport specifically geared for the lower purities. All of this adds big costs of course, so most distributors simply stick to the industry standard transport of Grade 5. That is why for and end user of helium, a lower grade can cost more than the higher grades."
This kinda makes me believe that it really isn't that difficult to refine the helium to be medical grade, all they have to do is chill it to a point where it becomes liquid, so it still doesn't make much sense that we're using it for balloons, especially since its actually harder to get lower "balloon grade" helium. So in essence, balloons are wasteful... and expensive?
It still seems crazy to use such a useful and rare resource on something so frivolous. We have a really finite amount of that stuff, like a hundred or so years worth, and getting it relies on the...
It still seems crazy to use such a useful and rare resource on something so frivolous.
We have a really finite amount of that stuff, like a hundred or so years worth, and getting it relies on the natural gas industry that we're trying (or should be trying) to phase out.
The only other way to get helium would be fusion reactions, but current fusion reactor designs actually consume more helium via losses than they produce (not to mention that they're not even close to economically viable).
It would make sense to conserve the stuff as much as we can, and at least make it expensive enough that people aren't wasting it by the pound at birthday parties.
@MimicSquid and @stu2b50 covered most of the points I would’ve make. The only thing to add is that depending on the design, pebbles could be crushed, which would result in a loss of fuel integrity...
The only thing to add is that depending on the design, pebbles could be crushed, which would result in a loss of fuel integrity for that pebble, which would contaminate the coolant loop. However, other high-temperature reactor designs exist that do not use pebble fuels.
I'm finding this "return" to gas cooled reactors most interesting. For a very long while, it seemed as if PWRs and other type of water-water reactors were dominant, and some focus was placed on...
I'm finding this "return" to gas cooled reactors most interesting. For a very long while, it seemed as if PWRs and other type of water-water reactors were dominant, and some focus was placed on molten salt for a while, but turns out that inert gas cooling is now back in the spotlight.
Super pumped (no pun intended) to see how this will turn out, especially with lower energy density, this could be an important development in small gen IV reactors.
From the article:
...
Comment box
Pretty cool tech but the US government sold all its helium in 1996. I hope that "a small amount of helium gas" is actually a small amount. I understand it to be in contention for uses in MRIs and other important things already. Natural gas extraction and by extension helium extraction is not super enviro friendly (methane leaks contribute a lot to emissions, and probably more than we realize), and IDK where we will get it if not from underground gas, which we are trying to get off of. I looked up the nuclear supply chain and it already looks a bit rough. Hopefully this can be solved.
Does anyone here have enough knowledge to challenge this? What is the catch? I support the use of nuclear energy instead of fossil fuels, but I am also trying to be realistic. Are we serious about a claim of "meltdown proof"? What about if the reactor is hit by an earthquake and tsunami?? Unlikely yeah. But catastrophic, as we already know.
I don't need convincing about nuclear's safety record, I've seen all the charts about air pollution from coal and gas. But I cannot tell marketing hype from reality with this industry. Is this passive safety fix something I can reasonably tell my nuclear-skeptic mother in law at Christmas dinner?
The wikipedia article on pebble-bed reactors has a good section on why they're much safer than the older designs your mom is thinking of, specifically the section on safety.
But in general, the heat is transferred away from the pebbles using an inert, fireproof gas which won't condense out, the pebbles are physically stable at higher temperatures than they can generate, and the container they're held in won't melt at the stable/uncontrolled temperature. So the worst that happens without power or human intervention is that it gets hot and sits there. I wouldn't go up and lick it, but it's not going to pollute the region.
Being meltdown proof isn’t all that rare for modern nuclear reactor designs. The benefit of pebble reactors is the simplicity in their cooling system. As we all know, the more complex, the more things can go wrong.
In terms of natural disasters, one issue is that if oxygen enters the core it can cause the graphite to ignite due to the high temperatures it runs at.
It is funny to me that helium is basically a finite non-renewable resource that is incredibly important for tons of industrial and medical applications and we still just use it to fill up balloons so they float.
I remember hearing about how we were running out of helium and thought that was kind of strange. Then the news cycle was all about how we're not running out of regular helium and there will be plenty of balloons for parties.
I never followed up until now, but there's a really interesting explanation of different helium grades on this company's site, as well as who buys what grades (semi-conductor manufacturers, cryolabs, scuba, military, and balloon salespersons). Crazy! I bet balloons make up most of the cubic volume of helium sales though!
Interesting, didn't know the difference between balloons and an MRI is only .0095% purity, I wouldn't have thought it would make that big of a difference. Is it really difficult to refine Grade 4.5 to Grade 5? It says that Grade 4.5 (for balloons) also can be used push gas in MRI applications, so I guess it still could have some medical purpose.
This kinda makes me believe that it really isn't that difficult to refine the helium to be medical grade, all they have to do is chill it to a point where it becomes liquid, so it still doesn't make much sense that we're using it for balloons, especially since its actually harder to get lower "balloon grade" helium. So in essence, balloons are wasteful... and expensive?
Thanks for the great link! I posted it top level so it would be easier to find. Hope you don’t mind!
It still seems crazy to use such a useful and rare resource on something so frivolous.
We have a really finite amount of that stuff, like a hundred or so years worth, and getting it relies on the natural gas industry that we're trying (or should be trying) to phase out.
The only other way to get helium would be fusion reactions, but current fusion reactor designs actually consume more helium via losses than they produce (not to mention that they're not even close to economically viable).
It would make sense to conserve the stuff as much as we can, and at least make it expensive enough that people aren't wasting it by the pound at birthday parties.
I think the main catch is that a meltdown is only one kind of failure. Skeptics worry about other things, too.
@MimicSquid and @stu2b50 covered most of the points I would’ve make.
The only thing to add is that depending on the design, pebbles could be crushed, which would result in a loss of fuel integrity for that pebble, which would contaminate the coolant loop. However, other high-temperature reactor designs exist that do not use pebble fuels.
I'm finding this "return" to gas cooled reactors most interesting. For a very long while, it seemed as if PWRs and other type of water-water reactors were dominant, and some focus was placed on molten salt for a while, but turns out that inert gas cooling is now back in the spotlight.
Super pumped (no pun intended) to see how this will turn out, especially with lower energy density, this could be an important development in small gen IV reactors.