Are you conjecturing the last part or is that directly from the researcher? I feel like scale would affect field strength as well so the relationship wouldn't be as simple.
Also, a researcher on the same channel in another video stated that for every doubling of magnetic field strength, power output gets a 16x increase. Or, the device gets 16x smaller for the same output.
Are you conjecturing the last part or is that directly from the researcher? I feel like scale would affect field strength as well so the relationship wouldn't be as simple.
The joke among physicists is that fusion is just 5 years away... for the past 30 years. Ever since the Fleischmann and Pons scandal, really. It seems like every few years we see a major...
ITER and its successor DEMO are likely to be our first, closest attempts at sustained fusion and they're still painfully far away. ITER won't start deuterium–tritium fusion tests until 2035, and...
ITER and its successor DEMO are likely to be our first, closest attempts at sustained fusion and they're still painfully far away. ITER won't start deuterium–tritium fusion tests until 2035, and the best we know about DEMO is that it won't start operations until "sometime in the 2050s".
I really just wish more countries were willing to pony up the cash for more research into these kinds of things. Lord only knows the US spends enough on the military every year that we could make so many breakthroughs if we were willing to re-allocate that money elsewhere. And it seems to be that is the primary problem with fusion research: no singular entity wants to pave the way due to perceived cost.
IMO it's more likely that it'll be MIT's SPARC reactor mentioned in the article, and within the decade. It's the same technology as ITER, which we're practically certain will work, just taking...
IMO it's more likely that it'll be MIT's SPARC reactor mentioned in the article, and within the decade. It's the same technology as ITER, which we're practically certain will work, just taking advantage of advances in superconductor technology that happened since the design of ITER to substantially miniaturize the design. The resulting reduction in build time is going to allow them to leapfrog ITER, I think. But definitely point taken on the abysmal funding situation of ITER and fusion research in general, the thing could've been built twenty years ago if the money was there, one of the most important technologies in human history and what it gets is hardly a patch compared to investment in new coal infrastructure.
SPARC shows promise no doubt, and I don't doubt the project as a whole will be successful. However I can't help but be somewhat skeptical of their timeline. SPARC has an aggressive construction...
SPARC shows promise no doubt, and I don't doubt the project as a whole will be successful. However I can't help but be somewhat skeptical of their timeline.
SPARC has an aggressive construction deadline of just 4 years, starting this year and ending in 2025. This is in spite of the fact that minor details such as how fuel will be injected have yet to be worked out. No doubt this is to try and compete with ITERs efforts, since ITER actually begins plasma tests in 2025 as well. However the reason ITER doesn't start fusion until 2035 is because its going to take them several years to actually produce enough tritium using their 'breeder blanket' for their fusion experiments. Presumably, SPARC would also need a calibration and testing period, and it also uses deuterium-tritium fuels to ignite fusion. However, where they're getting the tritium is less clear. So which project will attain a Q > 1 first really comes down to two things:
Can SPARC meet its construction deadline?
Can SPARC finish calibration and obtain enough tritium before ITER?
Overall I would probably put ITER as a safer bet just because there's a greater amount of transparent information about it, and it seems to already have a completed plan with consistently met milestones. SPARC is more of a wild card, but if it can meet deadlines and calibrate + gather tritium faster due it its smaller size, then it very well could succeed ahead of ITER.
Dumb question, is it important for the reactor to generate its own tritium just for the demonstration of net gain? Obviously it's going to be needed for economical power generation, but tritium...
Dumb question, is it important for the reactor to generate its own tritium just for the demonstration of net gain? Obviously it's going to be needed for economical power generation, but tritium can be sourced from elsewhere for the initial experiments.
My understanding is that tritium is extremely hard (and expensive) to get ahold of in large quantities. It’s fairly radioactive and only has a half life of 12.5 years, and that short half life...
My understanding is that tritium is extremely hard (and expensive) to get ahold of in large quantities. It’s fairly radioactive and only has a half life of 12.5 years, and that short half life means that it doesn’t really occur in nature, at least not near ground level. It also means it’s hard to store, since by definition if you were to wait 12.5 years, half of your supply would decay. It does occur in the atmosphere due to interaction with cosmic rays, but that doesn’t really pose us with an economic source either.
As a result, it’s really only produced in breeder fission reactors, and there’s only about six of those currently operating (or operable).
But to get to the root of your question, no it’s not important for the fusion reactor to produce its own tritium. In the case of ITER, it was just a decision that made sense due to cost, limited supply and the amount they would need for their fairly large reactor design. SPARC might be able to get away with just buying small quantities internationally, or possibly even from the US government, but as far as I’m aware they haven’t really publicly discussed that yet.
Here's the killer application for fusion power: FUSION POWERED AIRCRAFT CARRIERS. Boom, there's your funding. Let the US Navy fund that stuff. If they don't want to because it's too little of an...
Here's the killer application for fusion power: FUSION POWERED AIRCRAFT CARRIERS. Boom, there's your funding. Let the US Navy fund that stuff. If they don't want to because it's too little of an advantage over fission powered... (And to be fair Nuclear Aircraft Carrier sounds pretty sick already)
Then you go to the Air Force. Marvel style heli carrier. A flying air base.
One of the two surely has the spare change to fund all the fusion research we want, right?
I believe it is entirely possible to get to and live on Mars using existing fission reactor designs (probably liquid metal breeder designs). I’m more inclined to agree with you for long-distance...
I believe it is entirely possible to get to and live on Mars using existing fission reactor designs (probably liquid metal breeder designs).
I’m more inclined to agree with you for long-distance (>~10 ly) interstellar travel.
Hell, even solar doesn't sound unreasonable to me. Sure, it's going to be a bigger effort (and in the case of Mars, I can see that fission might be relatively low-risk and more economical), but...
Hell, even solar doesn't sound unreasonable to me. Sure, it's going to be a bigger effort (and in the case of Mars, I can see that fission might be relatively low-risk and more economical), but it's not that far from the sun. Certainly any space craft could reasonably be powered by solar. For the return trip you might want a planetside electrolytic fuel factory, which is going to be a big drain. However, it's also not a survival-critical part so nightly outages are no problem.
Once you go to the moons of jupiter or so though, the math changes a fair bit, as solar radiation is getting lower and lower.
Mars is big, and currently quite empty. In the long-long-term storing nuclear waste there might become an issue, but in the meantime they could just seal it up, and bury it at a designated...
Mars is big, and currently quite empty. In the long-long-term storing nuclear waste there might become an issue, but in the meantime they could just seal it up, and bury it at a designated location far away from any habitation zones. In The Martian that's precisely what they did with their RTG (radioisotope thermoelectric generator).
And in the future once some colonies with proper infrastructure exist they can deal with the waste by moving it to somewhere even safer, and burying it deeper, for proper long-term storage. It's likely to be a very very long time before that will be required though since the only people on Mars for the foreseeable future are likely to be hand-picked scientists, engineers, botanists, etc., who will know not to go near waste sites. So it's not like we're going to have to worry about some random idiot wandering into one, and accidentally getting irradiated by digging up, and then cracking open the waste containers.
This is one of the facilities at Idaho National Lab where Naval Reactor fuel is stored dry in large casks. While it isn’t an exact match, naval fuel shares a few characteristics with space-based...
This is one of the facilities at Idaho National Lab where Naval Reactor fuel is stored dry in large casks. While it isn’t an exact match, naval fuel shares a few characteristics with space-based fuels; namely high-enrichment and reasonable density. This is years of fuel for dozens of naval reactors. Even being very conservative, a single facility like this should be able to serve the needs of a Mars base before fuel storage becomes an issue. During the interim, one of the research goals might be dealing with the technical requirements for reprocessing in a lower-gravity environment. I also agree with what @cfabbro said; short, medium, and even long-terms, a geologic repository would be feasible on Mars.
It likely wouldn't be catastrophic in the way a fission reactor would be, since there would be no chance of a chain reaction or melt down. Worst case scenario would be if the superconducting...
It likely wouldn't be catastrophic in the way a fission reactor would be, since there would be no chance of a chain reaction or melt down. Worst case scenario would be if the superconducting magnets warmed beyond their operating parameters due to a coolant loss.
Once the superconductors stopped...well superconducting, the magnetic containment field would fail and release the huge ball of fusioning plasma inside. Fortunately, gas cools rapidly as it expands which would immediately stop any ongoing fusion and allow the gas to begin cooling. What happens afterwards is less clear. The huge ball of expanding gas might be contained by the vacuum vessel that ITER and similar designs would employ, though it would certainly cripple the plant and possibly even decommission it. What can be said with certainty, is that it would never grow to be a cataclysmic mushroom cloud like explosion; there simply isn't enough latent energy in any currently planned plant designs to create something like that. What you'd really be worried about would be any dangerous isotopes leaking out after the initial containment breach. Especially tritium, which is one of the fuels ITER will use, since it would react with air and form highly radioactive water that would then pollute the ground water, and take roughly a dozen years decay.
Regardless, it's important to understand that the sophisticated computer systems, interfaces, safety systems and oversight that exist even in a modern fission plant, (let alone something under the amount of public scrutiny that first generation fusion will be under), make the chances of this happening extremely remote.
The reaction is really delicate. At this scale, fusion isn't a chain reaction. Our sun is only self sustaining because of its size/gravity (e.g. Jupiter is too small for fusion, despite being...
The reaction is really delicate. At this scale, fusion isn't a chain reaction. Our sun is only self sustaining because of its size/gravity (e.g. Jupiter is too small for fusion, despite being 1000x the size of Earth). If the reactor's magnets or thermal systems fail, the reaction is delicate enough to burn itself out in a few seconds, at least according to ITER & IAEA websites.
I'm curious about this too. I really don't know anything about fusion technology but the MIT press release says it reaches temperatures of 100 million degrees. That's (significantly) hotter than...
I'm curious about this too. I really don't know anything about fusion technology but the MIT press release says it reaches temperatures of 100 million degrees. That's (significantly) hotter than the core of the sun. I know I'm just being an ignorant layperson but I'm having trouble wrapping my head around how an object can reach temperatures like that, without melting or vaporizing the entire building it's in. Or the entire city, or more. I can't comprehend how humans can even come within hundreds of kilometers of that kind of heat. How is any material found on Earth capable of insulating against it?
I must be fundamentally misunderstanding how dissipation of heat works at high temperatures. I'd love a plain-English breakdown of why out-hotting the sun isn't an instantly catastrophic act.
The simple explanation is that while the reactor plasma is the hottest thing in the solar system, there isn't much of it. Just a tiny amount compared to the mass of the reactor and the size of the...
The simple explanation is that while the reactor plasma is the hottest thing in the solar system, there isn't much of it. Just a tiny amount compared to the mass of the reactor and the size of the reaction chamber - like a handful of dust blowing around in a big room. Even at those high temperatures, it's not enough to melt through the reactor even if it gets in contact with it because of the mass difference. The reactor designs I've seen also run in pulses, so it's not running at maximum all of the time - just hitting that level for a few seconds with each firing. I'm sure we'd like to someday but we're more interested in just getting to net positive first. :P
Caution: No idea what I'm talking about. The sun is hot but it's also very very large. Even though it's much, much hotter, fusion can't hold a candle to the holy light of the sun. There's no...
Caution: No idea what I'm talking about.
The sun is hot but it's also very very large. Even though it's much, much hotter, fusion can't hold a candle to the holy light of the sun. There's no material that can withstand 100 million degrees, that's what the giant magnet is for. It keeps the plasma held in place without needing to touch it. I believe it's kept in a vacuum, so the only way for heat to escape is radiating away, which I think is the heat that would be extracted and used to power things?According to this page the free neutron that's produced by the fusion reaction is what heats the container and that's where the energy is extracted from. They don't mention the radiated energy or the energy that's released from the reaction itself, just the neutron. Maybe that's all that's significant?
MIT press release
Are you conjecturing the last part or is that directly from the researcher? I feel like scale would affect field strength as well so the relationship wouldn't be as simple.
The joke among physicists is that fusion is just 5 years away... for the past 30 years. Ever since the Fleischmann and Pons scandal, really.
It seems like every few years we see a major breakthrough:
1991 - Breakthrough in Nuclear Fusion Offers Hope for Power of Future
2009 - ITER: A brief history of fusion
2014 - Lockheed Claims Breakthrough on Fusion Energy
2017 - MIT Achieves Breakthrough in Nuclear Fusion
They're stumbling through the unknown, but at least it's clear they're making progress.
Oh certainly! Sorry, I didn't mean to be critical, I just meant that I wouldn't buy a house on Mars just yet ;)
ITER and its successor DEMO are likely to be our first, closest attempts at sustained fusion and they're still painfully far away. ITER won't start deuterium–tritium fusion tests until 2035, and the best we know about DEMO is that it won't start operations until "sometime in the 2050s".
I really just wish more countries were willing to pony up the cash for more research into these kinds of things. Lord only knows the US spends enough on the military every year that we could make so many breakthroughs if we were willing to re-allocate that money elsewhere. And it seems to be that is the primary problem with fusion research: no singular entity wants to pave the way due to perceived cost.
IMO it's more likely that it'll be MIT's SPARC reactor mentioned in the article, and within the decade. It's the same technology as ITER, which we're practically certain will work, just taking advantage of advances in superconductor technology that happened since the design of ITER to substantially miniaturize the design. The resulting reduction in build time is going to allow them to leapfrog ITER, I think. But definitely point taken on the abysmal funding situation of ITER and fusion research in general, the thing could've been built twenty years ago if the money was there, one of the most important technologies in human history and what it gets is hardly a patch compared to investment in new coal infrastructure.
SPARC shows promise no doubt, and I don't doubt the project as a whole will be successful. However I can't help but be somewhat skeptical of their timeline.
SPARC has an aggressive construction deadline of just 4 years, starting this year and ending in 2025. This is in spite of the fact that minor details such as how fuel will be injected have yet to be worked out. No doubt this is to try and compete with ITERs efforts, since ITER actually begins plasma tests in 2025 as well. However the reason ITER doesn't start fusion until 2035 is because its going to take them several years to actually produce enough tritium using their 'breeder blanket' for their fusion experiments. Presumably, SPARC would also need a calibration and testing period, and it also uses deuterium-tritium fuels to ignite fusion. However, where they're getting the tritium is less clear. So which project will attain a Q > 1 first really comes down to two things:
Overall I would probably put ITER as a safer bet just because there's a greater amount of transparent information about it, and it seems to already have a completed plan with consistently met milestones. SPARC is more of a wild card, but if it can meet deadlines and calibrate + gather tritium faster due it its smaller size, then it very well could succeed ahead of ITER.
Dumb question, is it important for the reactor to generate its own tritium just for the demonstration of net gain? Obviously it's going to be needed for economical power generation, but tritium can be sourced from elsewhere for the initial experiments.
My understanding is that tritium is extremely hard (and expensive) to get ahold of in large quantities. It’s fairly radioactive and only has a half life of 12.5 years, and that short half life means that it doesn’t really occur in nature, at least not near ground level. It also means it’s hard to store, since by definition if you were to wait 12.5 years, half of your supply would decay. It does occur in the atmosphere due to interaction with cosmic rays, but that doesn’t really pose us with an economic source either.
As a result, it’s really only produced in breeder fission reactors, and there’s only about six of those currently operating (or operable).
But to get to the root of your question, no it’s not important for the fusion reactor to produce its own tritium. In the case of ITER, it was just a decision that made sense due to cost, limited supply and the amount they would need for their fairly large reactor design. SPARC might be able to get away with just buying small quantities internationally, or possibly even from the US government, but as far as I’m aware they haven’t really publicly discussed that yet.
I wish we could trick the US military into believing fusion will give them a tactical advantage.
Here's the killer application for fusion power: FUSION POWERED AIRCRAFT CARRIERS. Boom, there's your funding. Let the US Navy fund that stuff. If they don't want to because it's too little of an advantage over fission powered... (And to be fair Nuclear Aircraft Carrier sounds pretty sick already)
Then you go to the Air Force. Marvel style heli carrier. A flying air base.
One of the two surely has the spare change to fund all the fusion research we want, right?
Clearly joking.... unless...
I always thought the joke was that fusion research is consistently being funded at such a level as to be 30-50 years away.
I believe it is entirely possible to get to and live on Mars using existing fission reactor designs (probably liquid metal breeder designs).
I’m more inclined to agree with you for long-distance (>~10 ly) interstellar travel.
Hell, even solar doesn't sound unreasonable to me. Sure, it's going to be a bigger effort (and in the case of Mars, I can see that fission might be relatively low-risk and more economical), but it's not that far from the sun. Certainly any space craft could reasonably be powered by solar. For the return trip you might want a planetside electrolytic fuel factory, which is going to be a big drain. However, it's also not a survival-critical part so nightly outages are no problem.
Once you go to the moons of jupiter or so though, the math changes a fair bit, as solar radiation is getting lower and lower.
Mars is big, and currently quite empty. In the long-long-term storing nuclear waste there might become an issue, but in the meantime they could just seal it up, and bury it at a designated location far away from any habitation zones. In The Martian that's precisely what they did with their RTG (radioisotope thermoelectric generator).
And in the future once some colonies with proper infrastructure exist they can deal with the waste by moving it to somewhere even safer, and burying it deeper, for proper long-term storage. It's likely to be a very very long time before that will be required though since the only people on Mars for the foreseeable future are likely to be hand-picked scientists, engineers, botanists, etc., who will know not to go near waste sites. So it's not like we're going to have to worry about some random idiot wandering into one, and accidentally getting irradiated by digging up, and then cracking open the waste containers.
This is one of the facilities at Idaho National Lab where Naval Reactor fuel is stored dry in large casks. While it isn’t an exact match, naval fuel shares a few characteristics with space-based fuels; namely high-enrichment and reasonable density. This is years of fuel for dozens of naval reactors. Even being very conservative, a single facility like this should be able to serve the needs of a Mars base before fuel storage becomes an issue. During the interim, one of the research goals might be dealing with the technical requirements for reprocessing in a lower-gravity environment. I also agree with what @cfabbro said; short, medium, and even long-terms, a geologic repository would be feasible on Mars.
Can you elaborate? Is the problem getting to Mars or sustaining life once we're there?
What happens if for some reason power to the containment bottle is disrupted or it fails in some other way? Is it a catastrophic failure?
It likely wouldn't be catastrophic in the way a fission reactor would be, since there would be no chance of a chain reaction or melt down. Worst case scenario would be if the superconducting magnets warmed beyond their operating parameters due to a coolant loss.
Once the superconductors stopped...well superconducting, the magnetic containment field would fail and release the huge ball of fusioning plasma inside. Fortunately, gas cools rapidly as it expands which would immediately stop any ongoing fusion and allow the gas to begin cooling. What happens afterwards is less clear. The huge ball of expanding gas might be contained by the vacuum vessel that ITER and similar designs would employ, though it would certainly cripple the plant and possibly even decommission it. What can be said with certainty, is that it would never grow to be a cataclysmic mushroom cloud like explosion; there simply isn't enough latent energy in any currently planned plant designs to create something like that. What you'd really be worried about would be any dangerous isotopes leaking out after the initial containment breach. Especially tritium, which is one of the fuels ITER will use, since it would react with air and form highly radioactive water that would then pollute the ground water, and take roughly a dozen years decay.
Regardless, it's important to understand that the sophisticated computer systems, interfaces, safety systems and oversight that exist even in a modern fission plant, (let alone something under the amount of public scrutiny that first generation fusion will be under), make the chances of this happening extremely remote.
The reaction is really delicate. At this scale, fusion isn't a chain reaction. Our sun is only self sustaining because of its size/gravity (e.g. Jupiter is too small for fusion, despite being 1000x the size of Earth). If the reactor's magnets or thermal systems fail, the reaction is delicate enough to burn itself out in a few seconds, at least according to ITER & IAEA websites.
I'm curious about this too. I really don't know anything about fusion technology but the MIT press release says it reaches temperatures of 100 million degrees. That's (significantly) hotter than the core of the sun. I know I'm just being an ignorant layperson but I'm having trouble wrapping my head around how an object can reach temperatures like that, without melting or vaporizing the entire building it's in. Or the entire city, or more. I can't comprehend how humans can even come within hundreds of kilometers of that kind of heat. How is any material found on Earth capable of insulating against it?
I must be fundamentally misunderstanding how dissipation of heat works at high temperatures. I'd love a plain-English breakdown of why out-hotting the sun isn't an instantly catastrophic act.
The simple explanation is that while the reactor plasma is the hottest thing in the solar system, there isn't much of it. Just a tiny amount compared to the mass of the reactor and the size of the reaction chamber - like a handful of dust blowing around in a big room. Even at those high temperatures, it's not enough to melt through the reactor even if it gets in contact with it because of the mass difference. The reactor designs I've seen also run in pulses, so it's not running at maximum all of the time - just hitting that level for a few seconds with each firing. I'm sure we'd like to someday but we're more interested in just getting to net positive first. :P
Caution: No idea what I'm talking about.
The sun is hot but it's also very very large. Even though it's much, much hotter, fusion can't hold a candle to the holy light of the sun. There's no material that can withstand 100 million degrees, that's what the giant magnet is for. It keeps the plasma held in place without needing to touch it.
I believe it's kept in a vacuum, so the only way for heat to escape is radiating away, which I think is the heat that would be extracted and used to power things?According to this page the free neutron that's produced by the fusion reaction is what heats the container and that's where the energy is extracted from. They don't mention the radiated energy or the energy that's released from the reaction itself, just the neutron. Maybe that's all that's significant?