Pebble and molten salt reactors still benefit from everything that was learned from past mistakes. If you had a pebble or MSR reactor with Chernobyl-era knowledge and experience, Chernobyl would likely still have happened: still stuck with a massive power surge once radon poisoning clears up. Same for TMI and Fukushima. Pebbles and molten salt may be more convenient and safer to handle and process but there is very little they can do to prevent operator, design and construction errors.
You mean Xenon poisoning? That problem doesn't exist in an MSR, as it bubbles out and doesn't build up. Just one of many ways in which MSRs are inherently superior.
Pebbles still trap volatile fission products and poisons, and could pose a problem if damaged. Moreover, they magnify the waste stream with graphite, and make reprocessing virtually impossible. As with other solid fuels, they can not be burned completely, and require long term isolation. Of course, they also require an expensive fabrication process up front as well. All considered, I'm not sure why so many people find them attractive, when fluid fuels are so clearly superior.
Aside from the apocalypse, that is one of the things I worry about. Shills are bad enough today, but imagine if they could be deployed programmatically; just about any form of online speech could be drowned out with ease. That is assuming that the government/corporations aren't already using AI to accomplice pervasive censorship.
Before this gets out of hand, we need to head it off by deploying peer to peer communications systems with a pervasive trust model. This doesn't necessarily preclude anonymity or AI participation, but they would have a significantly more difficult time of gaining trust in the first place.
I'm assuming that the speed is speed of encoding rather than playback? This isn't something that many people are particularly worried about.
I think the 40% slower than vp8 was for playback. However, encoding speed also has to be reasonable, or there will be no content. With youtube, google may have a good head start if they succeed in getting others on board.
As your information is all taken from Google please take it with a huge pinch of salt. Google are bound to present a rosy view of VP9 in comparison with h265 given their investment in it.
Of course, but if the presented videos are any indication, it looks quite good. It doesn't have to be perfect. As long as it is significantly better than h.264 and close to h.265, it should find widespread use. Opus is also an excellent audio codec with very low latency, which will make this a good option for real time communications.
Personally I'm not keen on this. I don't care if its royalty free and unencumbered by patents. I don't want a single entity in control of a standard and regardless of the open nature of this Google are still in control. If this were Apple* or releasing a patent free codec to the world would you be so welcoming?
* Don't be dismissive of this Apple/NeXT do have a decent record of open source software releases.
Once the bitstream is frozen and the codec is open, you are free to use it as you like. The code is already available under a BSD-style license, though I do expect that a formal standard will be forthcoming. The availability of hardware should also provide incentive not to break compatibility in future versions.
I don't see how having the MPEG LA in control of any standard is a better option. The primary difference is that developers are free to incorporate this into applications without the trouble and cost of licensing. That directly benefits users, so perhaps you should care about royaltys and patents. The x.264 project is great, but it is limited in that respect.
From a technical point of view it's basically h265's peer. That's partially because it's largely based on the same tech as h265, in the same way VP8 was largely similar to h264. And is speculated that it has the same licensing issues that VP8 had, for most of the same reasons.
And the speed issue is entirely due to an almost complete lack of hardware support. And while h265 already has announced and demonstrated support, I am not aware of any VP9 support so far.
And doing VP9 decode in software has order-of-magnitude higher requirements than VP8. If YouTube serves up a VP9 video to your phone, you'll wish for the good old days of Flash video.
From the q&a afterward, it is mentioned that average vp9 quality is within 1% of h.265, but it didn't sound like h.265 was anywhere near ready to roll out, with the only available option being a horrifically slow reference encoder. As for speed, they claim it is about 40% slower than vp8, which is twice as fast as h.264. As such, vp9 should handily outperform h.264 in software.
The open source and royalty free vp9/opus combination sounds like an very compelling option for the html5 video tag, and may become a de facto standard before h.265 is widely deployed. Hardware support for vp9 is also in the works, so if the codec lives up to the claims, there no longer appears to be any good reason to put up with the MPEG LA.
As the folk at Transmeta (and others) demonstrated logic to decode any random ISA and drive a RISC core faster than the old VAX microcode days is very possible. This seems to be the way of modern processors. So ARM/x86/x86_64 ISA almost does not matter except to the compiler and API/ABI folk. If you want to go fast feed your compiler folk well.
One of the best ways you can help the compiler folk is with an orthogonal and sensible architecture. Furthermore, consider that generating good code is a problem that must be solved for every language, so starting with a good ISA makes for a lot less work.
The ZFS code is actually very readable and well organized. The choice of an alternate layering model is logical and useful. That said, I would not be surprised if the NTFS source is truly a horror to behold.
I considered including an explanation to head off this inevitable response, but thought it was off topic. The reason is not a matter of technological advancement, but of the fundamental physics of the tokamak. When the physics makes something impossible, I occasionally resort to the term "never".
The tokamak has to be enormous for it to work, and that has a direct impact on the economics. Even today, for 1GW fission reactors, financing is difficult, and they are nowhere near as complex. Beyond the prohibitive economics, there are many reasons why we will not be building 10GW+ tokamaks, and yet there is no way to scale them down. We need distributed power sources, which are mass manufacturable and affordable, so that they can be deployed rapidly.
There are many promising (and far less expensive) approaches to fusion, and pouring endless billions into the tokomak is asinine. For people who are so risk averse, it really is ironic that we are willing to fund one approach to the exclusion of all others.
You didn't bother to read those sections I mentioned, did you? Nowhere did I say that scramjets work well in theory, quite the opposite. Why would you pursue something that doesn't work well even in theory, at such great cost? What makes SABRE a better design is a sound concept offering greater potential efficiency across the spectrum, and general usefulness.
Cooling the incoming air has very real advantages in the thermodynamic cycle as well relaxing requirements for materials.
Your analogy doesn't work, as SABRE is actually a sound concept, with well understood physics. It is an involved, but tractable engineering problem. Tokamak fusion is not, and will never produce economical power, even if it works. Nor are most other fusion options attractive when compared to the simplicity and economics possible with molten salt fission reactors. (The exception being aneutronic pB11 fusion in a Polywell, DPF, or such, but those are a much harder nut to crack, if they are even possible.)
Scramjets are theoretically simple, but not so in practice, and merely testing them involves great trouble and expense. Nor are they even that attractive in theory, with a very low thrust/weight ratio, and only useful when operating near hypersonic speeds, and in a narrow range at that. For more details, take a look at the Performance and Advantages sections in the wiki on the SABRE engine that I linked, there is discussion of scramjets as well.
Was it ever a military concept? All I'm aware of, was that it ended up with a secret classification when they put it through the UK patent office, a very unfortunate result that they hope not to repeat.
SABRE is a sound concept which combines proven technologies in a new way, enabled by the novel heat exchanger. Not only has the heat exchanger has been demonstrated, the ESA has thoroughly examined the concept and finds no fault with the engine. The helium (which is not liquid by the way) is not consumed, nor are prohibitively large quantities required.
By your reasoning, there would never be any innovation at all, and we would live in a technologically static world. I do not understand the compulsion of people to endlessly and vehemently complain about the impossibility of perfectly sound concepts. Progress still happens, though probably at a considerably reduced rate thanks to this prevailing mindset.
Seriously, what is with the total lack of vision these days? Why is it that everything that can't already be purchased, is considered to be impossible? If not a sound concept with demonstrated components, what, if anything, will convince people to support innovation? I'm genuinely curious, as this seems to be holding up other critically important innovations such as molten salt reactors.
A fascinating development, but I worry that the applications are limited to delivering bombs. Since the engine doesn't even function below hypersonic speeds, a plane and rocket are necessary to even launch them, and that naturally limits the size. As such, I don't particularly see the development as a positive thing in the near term, nor does it make me feel any better that the US military is the one doing it.
A hybrid jet/rocket engine like the SABRE is far more attractive, as it can deliver Skylon from runway to space, and is efficient throughout. The remarkable enabling technology is a precooler which cools incoming air from 1000C to -150C in milliseconds, and has already been successfully demonstrated.
Furthermore, there is a also a variant optimized for atmospheric flight called Scimitar, which uses the precooler with a high-bypass turbofan engine, giving it good efficiency and subsonic exhaust velocities at low speeds. This flexibility and broad efficiency allow the A2 to operate over land as well, overcoming the limitations of the Concorde. It has the potential to make commercial hypersonic flight ubiquitous.
One more thing, solar efficiency has a hard limit of 100%, and there is only so much sunshine. During half the day there is none at all. No amount of progress will change those fundamental limits. On a cloudless day, the average falling on earth is approximately 250 W/m^2. See more about insolation. Wind has its own limits and challenges.
You could say the same thing about ubiquitous superconductors. The technology simply isn't ready, and there is no reason to expect it will be anytime soon. Until then, like superconductors, it will be consigned to niche uses, and not displace any fossil fuel generation in the developing world, which is absolutely essential. Subsidies should be spent on developing technologies, not deploying technologies which can't succeed.
Efficiently collecting diffuse sources of energy like wind and solar is an extremely difficult challenge. Massive storage is an absolute requirement. Transmission infrastructure is also expensive, and the low capacity factors of wind and solar compound this expense. For example, using a generous 25% capacity factor for wind, it is necessary to install four times the capacity, which also requires four times the transmission infrastructure. Worse yet, all of that infrastructure must be sized to handle the full load. The economics simply don't work yet, and are far from doing so.
Even if they did, wind and solar still waste a huge amount of land and resources to harvest a relative pittance of energy, so the environmental footprint will still be much larger than any sort of nuclear, even if you want to include exclusion zones. People really don't appreciate just how much land, steel, concrete, rare earths and such are required. Nor the impact of mining and processing all those resources, to say nothing of covering vast expanses of land, and the cost of regular replacement and maintenance. It is a nightmare.
Yes, I'm suggesting that we spend a modest amount to finish the development and commercialization of molten salt reactors. There has already been extensive research at ORNL, and multiple successful test reactors. We know what these reactors are capable of, and there is very little technological uncertainty. The results are basically guaranteed if the government allows it to happen.
The difficulty of finishing the development of a well understood technology is worlds apart from the breakthroughs required for fusion or massive and cheap energy storage and transmission. To depend on the latter happening any time soon isn't mere wishful thinking, it is folly.
Denmark depends on their neighbors pumped hydro to dump excess wind generation, and draw upon when the wind isn't blowing. Nice arrangement for them, as it is essential for the success of wind or solar. Sadly, availability is limited, and Germany's choice to abandon nuclear is also stressing the grid in that region, and causing trouble for neighboring nations.
More renewables isn't enough to provide anything more than self satisfaction. At the current rate, it would take centuries to have any significant impact, and the laws of reality will prevent it from ever providing a significant fraction. Despite extensive effort, Germany is discovering this right now, and they too are ramping coal and gas generation.
It isn't a problem of inaction, but of the wrong action, which is arguably worse. "Environmentalists" would have us continue to pour money and resources into uneconomical "solutions" which can not possibly achieve our objectives. Once all of our money and resources are spent, implementing a workable solution becomes near impossible. The problem is that they refuse to face reality and have taken the only workable solution off the table. (Or they choose to live in a different reality, where pro-environment is synonymous with anti-human, and a collapse in population is an accepted part of the "solution".)
The crucial point is that none of our current technologies are capable of providing affordable power at the scale we require. Renewables like wind and solar are hugely resource intensive, making them inherently costly both to the environment and people. They are also unreliable, and require a non-existant storage technology which is an even more difficult problem than fusion. Pumped hydro storage is the only one currently available that is even close to economical at the scale required, but it isn't universally available. We should not be pursuing an energy policy that by its very nature requires a miraculous breakthrough to succeed, and would otherwise result in spectacular failure.
Those that appreciate the scope of the problem often remark that we need a "broad mix of technologies" to meet our energy needs. That is a translation for "none of our current options are sufficient", but it is a resigned mentality, because there is no guarantee that a combination of insufficient technologies will ever be sufficient. Rather, there is good evidence that the sum total will never be sufficient in the absence of reliable baseload electricity from fossil fuels or nuclear.
Fortunately, like you said, it is not all doom and gloom. There happens to be a proven technology that would be sufficient if we developed it. It has been providing clean and cheap electricity for decades with a minimal environmental footprint, the only issue being the large (and growing) up front capital cost, and the fact that we can't build plants fast enough. While useful, conventional nuclear to which I am referring is not the solution, and will never be sufficient. Fortunately, unlike the other options, nuclear has huge unrealized potential, and with a bit of development, it could become the solution we seek.
Molten salt reactors are fundamentally different from conventional nuclear, and solve all the problems which plague solid-fueled conventional reactors, while safely operating at vastly greater efficiency. The so-called nuclear waste problem is a product of conventional reactors which are nearly 100% inefficient , and that is not an exaggeration. The fission process is such that if not completed, it produces nasty intermediate products which then contaminate the rest of the fuel, a problem severely exacerbated by only consuming a tiny fraction of the fuel, before pulling it from the reactor and adding it to the growing pile of "spent fuel". The truth though, is that "spent fuel" is almost entirely unspent, and the problem essentially disappears if we completely consume the fuel. Rather than a waste problem, it is a vast reserve of energy waiting to be tapped.
The problem isn't producing clean energy, it is doing so affordably, so that the entire world embraces it. Robert Hargraves discusses this in his book, THORIUM: energy cheaper than coal.
Tell that to the people directly involved with Chernobyl. You seem to have forgotten some basic chemistry, that is reaction rates, and even what reactions happens, are temperature dependent.
No concern to you, is not the same as not a concern. These concerns where raised/pointed out in scientific papers on LFTR.
Here you go. For various reasons, it is not a concern in a LFTR.
Still, there is still no graphite present in the drain tanks, so it is largely academic.
Regardless, the question isn't wether conventional nuclear is the most expensive, but if renewables can ever be cheaper than coal and natural gas, and deployed at a rate of say 100MW a day. (and with the low capacity factor of wind/solar, they would require several times that, not to mention several times the transmission infrastructure.)
Renewables simply don't cut it at the scales we require. The developing world is building coal plants instead. For that matter, even Germany is ramping coal power, burning the dirtiest brown coal.
Fluoride salts are very stable with a ~1000C liquide range, not water soluble, and do not react violently with air or water, no matter how many times you and others insist on repeating this FUD. Even in the event of an accident, the fission products remain safely locked up in the salts and will eventually freeze solid with no intervention. Obviously, you want to avoid flooding for any number of reasons, but there is no requirement to build the plants anywhere near water, or use water for cooling.
Conventional reactors trap gaseous fission products within a solid with very poor thermal conductivity, under extreme pressure, in zirconium cladding which burns when cooling is lost. How is that better than liquid fuel at atmospheric pressure which naturally contains all of the fission products?
Thermal breeding of U-233 was demonstrated in the Shippingport reactor, and there are no reasons to expect that it will not work in LFTR as well. U-233 releases about 2.3 neutrons per fission, which while slow for breeding, is not that tight for breaking even.
LFTR and other molten salt reactors have significantly less decay heat to deal with, since they do not trap the volatile fission products within a solid fuel. This reduces the difficulty of the problem from the outset. Furthermore, the drain tank is separate, contains no moderator, and can be optimized for passive decay heat removal--something not possible with solid fueled reactors.
Also, your graphite red herring is not only irrelevant, but false. This has been studied, and graphite does not burn in air. It requires specific conditions; the presence of water IIRC. Again, molten salt reactors will not be cooled by water, nor need they be constructed anywhere near the reach of tsunamis or floods. (Though, there are no active systems to fail anyway...) The floride salt and water reaction is also a red herring; the reaction proceeds so slowly that it poses no concern.
| will mechanically drain its operating fluid into a vessel where it will just sit there.
Until the rain and floods come in after the accident in which case you have steam explosions and radioactive waste in a highly water-soluble liquid combing to make all sorts of fun.
The salts are not water soluble, and have no violent reactions with either air or water. Contrary to your claims of "all sorts of fun", ORNL even dumped some in a pool at one point, and it did little more than create some steam. Fluoride salts are among the most chemically stable substances on earth, and both the fissile and fission products remain safely dissolved in just about any imaginable circumstances. Even so, keeping water out is not an issue, as there is no need to site the plants anywhere near water.
A LFTR is a chemical reprocessing plant with astonishingly racdioactive liquid (since it just came out of the fission core) circulating at hundreds of degrees with caustic chemical properties. There will be leaks. There will be breaches. Every drop is a huge problem. There will be----well anything that can go wrong in a hot chemical plant---now add in the fact that humans even in suits can't go in there for decades if something is wrong.
The sort of reprocessing done for a LFTR is very different and far simpler than conventional nuclear reprocessing, and the rates for continuous processing are also very modest. The entire reprocessing system will fit along with the core in a small hot cell. The most dangerous volatile fission products are continuously off-gassed, and do not build up as in solid fuels. Thus even in the event of an accident, there is a very small amount of residual radioactivity, and still no driving force to push it into the environment.
Nuclear reprocessing plants are the nastiest ones, because of the combination of liquids and radiaoactivity. I do not trust a utility with such an installation, and only want a tiny number of them, not every power plant to be one.
If the continuous processing bothers you, there are variations of molten salt reactors like the DMSR that leave all of the fission products dissolved in the salts, and only require processing every 10-30 years. By the tone of your post though, it sounds like you are only interested in fear mongering, and not rational discussion.
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Pebble and molten salt reactors still benefit from everything that was learned from past mistakes. If you had a pebble or MSR reactor with Chernobyl-era knowledge and experience, Chernobyl would likely still have happened: still stuck with a massive power surge once radon poisoning clears up. Same for TMI and Fukushima. Pebbles and molten salt may be more convenient and safer to handle and process but there is very little they can do to prevent operator, design and construction errors.
You mean Xenon poisoning? That problem doesn't exist in an MSR, as it bubbles out and doesn't build up. Just one of many ways in which MSRs are inherently superior.
Pebbles still trap volatile fission products and poisons, and could pose a problem if damaged. Moreover, they magnify the waste stream with graphite, and make reprocessing virtually impossible. As with other solid fuels, they can not be burned completely, and require long term isolation. Of course, they also require an expensive fabrication process up front as well. All considered, I'm not sure why so many people find them attractive, when fluid fuels are so clearly superior.
Aside from the apocalypse, that is one of the things I worry about. Shills are bad enough today, but imagine if they could be deployed programmatically; just about any form of online speech could be drowned out with ease. That is assuming that the government/corporations aren't already using AI to accomplice pervasive censorship.
Before this gets out of hand, we need to head it off by deploying peer to peer communications systems with a pervasive trust model. This doesn't necessarily preclude anonymity or AI participation, but they would have a significantly more difficult time of gaining trust in the first place.
I'm assuming that the speed is speed of encoding rather than playback? This isn't something that many people are particularly worried about.
I think the 40% slower than vp8 was for playback. However, encoding speed also has to be reasonable, or there will be no content. With youtube, google may have a good head start if they succeed in getting others on board.
As your information is all taken from Google please take it with a huge pinch of salt. Google are bound to present a rosy view of VP9 in comparison with h265 given their investment in it.
Of course, but if the presented videos are any indication, it looks quite good. It doesn't have to be perfect. As long as it is significantly better than h.264 and close to h.265, it should find widespread use. Opus is also an excellent audio codec with very low latency, which will make this a good option for real time communications.
Personally I'm not keen on this. I don't care if its royalty free and unencumbered by patents. I don't want a single entity in control of a standard and regardless of the open nature of this Google are still in control. If this were Apple* or releasing a patent free codec to the world would you be so welcoming?
* Don't be dismissive of this Apple/NeXT do have a decent record of open source software releases.
Once the bitstream is frozen and the codec is open, you are free to use it as you like. The code is already available under a BSD-style license, though I do expect that a formal standard will be forthcoming. The availability of hardware should also provide incentive not to break compatibility in future versions.
I don't see how having the MPEG LA in control of any standard is a better option. The primary difference is that developers are free to incorporate this into applications without the trouble and cost of licensing. That directly benefits users, so perhaps you should care about royaltys and patents. The x.264 project is great, but it is limited in that respect.
From a technical point of view it's basically h265's peer. That's partially because it's largely based on the same tech as h265, in the same way VP8 was largely similar to h264. And is speculated that it has the same licensing issues that VP8 had, for most of the same reasons.
And the speed issue is entirely due to an almost complete lack of hardware support. And while h265 already has announced and demonstrated support, I am not aware of any VP9 support so far.
And doing VP9 decode in software has order-of-magnitude higher requirements than VP8. If YouTube serves up a VP9 video to your phone, you'll wish for the good old days of Flash video.
From the q&a afterward, it is mentioned that average vp9 quality is within 1% of h.265, but it didn't sound like h.265 was anywhere near ready to roll out, with the only available option being a horrifically slow reference encoder. As for speed, they claim it is about 40% slower than vp8, which is twice as fast as h.264. As such, vp9 should handily outperform h.264 in software.
The open source and royalty free vp9/opus combination sounds like an very compelling option for the html5 video tag, and may become a de facto standard before h.265 is widely deployed. Hardware support for vp9 is also in the works, so if the codec lives up to the claims, there no longer appears to be any good reason to put up with the MPEG LA.
As the folk at Transmeta (and others) demonstrated logic to decode any random ISA and drive a RISC core faster than the old VAX microcode days is very possible. This seems to be the way of modern processors. So ARM/x86/x86_64 ISA almost does not matter except to the compiler and API/ABI folk. If you want to go fast feed your compiler folk well.
One of the best ways you can help the compiler folk is with an orthogonal and sensible architecture. Furthermore, consider that generating good code is a problem that must be solved for every language, so starting with a good ISA makes for a lot less work.
The ZFS code is actually very readable and well organized. The choice of an alternate layering model is logical and useful. That said, I would not be surprised if the NTFS source is truly a horror to behold.
I considered including an explanation to head off this inevitable response, but thought it was off topic. The reason is not a matter of technological advancement, but of the fundamental physics of the tokamak. When the physics makes something impossible, I occasionally resort to the term "never".
The tokamak has to be enormous for it to work, and that has a direct impact on the economics. Even today, for 1GW fission reactors, financing is difficult, and they are nowhere near as complex. Beyond the prohibitive economics, there are many reasons why we will not be building 10GW+ tokamaks, and yet there is no way to scale them down. We need distributed power sources, which are mass manufacturable and affordable, so that they can be deployed rapidly.
There are many promising (and far less expensive) approaches to fusion, and pouring endless billions into the tokomak is asinine. For people who are so risk averse, it really is ironic that we are willing to fund one approach to the exclusion of all others.
You didn't bother to read those sections I mentioned, did you? Nowhere did I say that scramjets work well in theory, quite the opposite. Why would you pursue something that doesn't work well even in theory, at such great cost? What makes SABRE a better design is a sound concept offering greater potential efficiency across the spectrum, and general usefulness.
Cooling the incoming air has very real advantages in the thermodynamic cycle as well relaxing requirements for materials.
Your analogy doesn't work, as SABRE is actually a sound concept, with well understood physics. It is an involved, but tractable engineering problem. Tokamak fusion is not, and will never produce economical power, even if it works. Nor are most other fusion options attractive when compared to the simplicity and economics possible with molten salt fission reactors. (The exception being aneutronic pB11 fusion in a Polywell, DPF, or such, but those are a much harder nut to crack, if they are even possible.)
Scramjets are theoretically simple, but not so in practice, and merely testing them involves great trouble and expense. Nor are they even that attractive in theory, with a very low thrust/weight ratio, and only useful when operating near hypersonic speeds, and in a narrow range at that. For more details, take a look at the Performance and Advantages sections in the wiki on the SABRE engine that I linked, there is discussion of scramjets as well.
Was it ever a military concept? All I'm aware of, was that it ended up with a secret classification when they put it through the UK patent office, a very unfortunate result that they hope not to repeat.
SABRE is a sound concept which combines proven technologies in a new way, enabled by the novel heat exchanger. Not only has the heat exchanger has been demonstrated, the ESA has thoroughly examined the concept and finds no fault with the engine. The helium (which is not liquid by the way) is not consumed, nor are prohibitively large quantities required.
By your reasoning, there would never be any innovation at all, and we would live in a technologically static world. I do not understand the compulsion of people to endlessly and vehemently complain about the impossibility of perfectly sound concepts. Progress still happens, though probably at a considerably reduced rate thanks to this prevailing mindset.
Seriously, what is with the total lack of vision these days? Why is it that everything that can't already be purchased, is considered to be impossible? If not a sound concept with demonstrated components, what, if anything, will convince people to support innovation? I'm genuinely curious, as this seems to be holding up other critically important innovations such as molten salt reactors.
A fascinating development, but I worry that the applications are limited to delivering bombs. Since the engine doesn't even function below hypersonic speeds, a plane and rocket are necessary to even launch them, and that naturally limits the size. As such, I don't particularly see the development as a positive thing in the near term, nor does it make me feel any better that the US military is the one doing it.
A hybrid jet/rocket engine like the SABRE is far more attractive, as it can deliver Skylon from runway to space, and is efficient throughout. The remarkable enabling technology is a precooler which cools incoming air from 1000C to -150C in milliseconds, and has already been successfully demonstrated.
Furthermore, there is a also a variant optimized for atmospheric flight called Scimitar, which uses the precooler with a high-bypass turbofan engine, giving it good efficiency and subsonic exhaust velocities at low speeds. This flexibility and broad efficiency allow the A2 to operate over land as well, overcoming the limitations of the Concorde. It has the potential to make commercial hypersonic flight ubiquitous.
One more thing, solar efficiency has a hard limit of 100%, and there is only so much sunshine. During half the day there is none at all. No amount of progress will change those fundamental limits. On a cloudless day, the average falling on earth is approximately 250 W/m^2. See more about insolation. Wind has its own limits and challenges.
You could say the same thing about ubiquitous superconductors. The technology simply isn't ready, and there is no reason to expect it will be anytime soon. Until then, like superconductors, it will be consigned to niche uses, and not displace any fossil fuel generation in the developing world, which is absolutely essential. Subsidies should be spent on developing technologies, not deploying technologies which can't succeed.
Efficiently collecting diffuse sources of energy like wind and solar is an extremely difficult challenge. Massive storage is an absolute requirement. Transmission infrastructure is also expensive, and the low capacity factors of wind and solar compound this expense. For example, using a generous 25% capacity factor for wind, it is necessary to install four times the capacity, which also requires four times the transmission infrastructure. Worse yet, all of that infrastructure must be sized to handle the full load. The economics simply don't work yet, and are far from doing so.
Even if they did, wind and solar still waste a huge amount of land and resources to harvest a relative pittance of energy, so the environmental footprint will still be much larger than any sort of nuclear, even if you want to include exclusion zones. People really don't appreciate just how much land, steel, concrete, rare earths and such are required. Nor the impact of mining and processing all those resources, to say nothing of covering vast expanses of land, and the cost of regular replacement and maintenance. It is a nightmare.
Yes, I'm suggesting that we spend a modest amount to finish the development and commercialization of molten salt reactors. There has already been extensive research at ORNL, and multiple successful test reactors. We know what these reactors are capable of, and there is very little technological uncertainty. The results are basically guaranteed if the government allows it to happen.
The difficulty of finishing the development of a well understood technology is worlds apart from the breakthroughs required for fusion or massive and cheap energy storage and transmission. To depend on the latter happening any time soon isn't mere wishful thinking, it is folly.
Denmark depends on their neighbors pumped hydro to dump excess wind generation, and draw upon when the wind isn't blowing. Nice arrangement for them, as it is essential for the success of wind or solar. Sadly, availability is limited, and Germany's choice to abandon nuclear is also stressing the grid in that region, and causing trouble for neighboring nations.
More renewables isn't enough to provide anything more than self satisfaction. At the current rate, it would take centuries to have any significant impact, and the laws of reality will prevent it from ever providing a significant fraction. Despite extensive effort, Germany is discovering this right now, and they too are ramping coal and gas generation.
It isn't a problem of inaction, but of the wrong action, which is arguably worse. "Environmentalists" would have us continue to pour money and resources into uneconomical "solutions" which can not possibly achieve our objectives. Once all of our money and resources are spent, implementing a workable solution becomes near impossible. The problem is that they refuse to face reality and have taken the only workable solution off the table. (Or they choose to live in a different reality, where pro-environment is synonymous with anti-human, and a collapse in population is an accepted part of the "solution".)
The crucial point is that none of our current technologies are capable of providing affordable power at the scale we require. Renewables like wind and solar are hugely resource intensive, making them inherently costly both to the environment and people. They are also unreliable, and require a non-existant storage technology which is an even more difficult problem than fusion. Pumped hydro storage is the only one currently available that is even close to economical at the scale required, but it isn't universally available. We should not be pursuing an energy policy that by its very nature requires a miraculous breakthrough to succeed, and would otherwise result in spectacular failure.
Those that appreciate the scope of the problem often remark that we need a "broad mix of technologies" to meet our energy needs. That is a translation for "none of our current options are sufficient", but it is a resigned mentality, because there is no guarantee that a combination of insufficient technologies will ever be sufficient. Rather, there is good evidence that the sum total will never be sufficient in the absence of reliable baseload electricity from fossil fuels or nuclear.
Fortunately, like you said, it is not all doom and gloom. There happens to be a proven technology that would be sufficient if we developed it. It has been providing clean and cheap electricity for decades with a minimal environmental footprint, the only issue being the large (and growing) up front capital cost, and the fact that we can't build plants fast enough. While useful, conventional nuclear to which I am referring is not the solution, and will never be sufficient. Fortunately, unlike the other options, nuclear has huge unrealized potential, and with a bit of development, it could become the solution we seek.
Molten salt reactors are fundamentally different from conventional nuclear, and solve all the problems which plague solid-fueled conventional reactors, while safely operating at vastly greater efficiency. The so-called nuclear waste problem is a product of conventional reactors which are nearly 100% inefficient , and that is not an exaggeration. The fission process is such that if not completed, it produces nasty intermediate products which then contaminate the rest of the fuel, a problem severely exacerbated by only consuming a tiny fraction of the fuel, before pulling it from the reactor and adding it to the growing pile of "spent fuel". The truth though, is that "spent fuel" is almost entirely unspent, and the problem essentially disappears if we completely consume the fuel. Rather than a waste problem, it is a vast reserve of energy waiting to be tapped.
The problem isn't producing clean energy, it is doing so affordably, so that the entire world embraces it. Robert Hargraves discusses this in his book, THORIUM: energy cheaper than coal.
Thanks to lobbying, even in the US, Israel's interests are often placed above that of Americans. For a recent example, see this.
That's rich, coming from someone who finishes with an ad hominem.
Perhaps you should read about the Windscale fire:
During the accident, uranium fuel caught fire — not the graphite moderator as is widely assumed.
There is a discussion of graphite fire risk here, and the specific circumstances which can cause problems for graphite are not present in a LFTR.
Tell that to the people directly involved with Chernobyl. You seem to have forgotten some basic chemistry, that is reaction rates, and even what reactions happens, are temperature dependent.
No concern to you, is not the same as not a concern. These concerns where raised/pointed out in scientific papers on LFTR.
Here you go. For various reasons, it is not a concern in a LFTR.
Still, there is still no graphite present in the drain tanks, so it is largely academic.
From the zealot who brought us the biofuels disaster? No thanks.
Regardless, the question isn't wether conventional nuclear is the most expensive, but if renewables can ever be cheaper than coal and natural gas, and deployed at a rate of say 100MW a day. (and with the low capacity factor of wind/solar, they would require several times that, not to mention several times the transmission infrastructure.)
Renewables simply don't cut it at the scales we require. The developing world is building coal plants instead. For that matter, even Germany is ramping coal power, burning the dirtiest brown coal.
Fluoride salts are very stable with a ~1000C liquide range, not water soluble, and do not react violently with air or water, no matter how many times you and others insist on repeating this FUD. Even in the event of an accident, the fission products remain safely locked up in the salts and will eventually freeze solid with no intervention. Obviously, you want to avoid flooding for any number of reasons, but there is no requirement to build the plants anywhere near water, or use water for cooling.
Conventional reactors trap gaseous fission products within a solid with very poor thermal conductivity, under extreme pressure, in zirconium cladding which burns when cooling is lost. How is that better than liquid fuel at atmospheric pressure which naturally contains all of the fission products?
Thermal breeding of U-233 was demonstrated in the Shippingport reactor, and there are no reasons to expect that it will not work in LFTR as well. U-233 releases about 2.3 neutrons per fission, which while slow for breeding, is not that tight for breaking even.
LFTR and other molten salt reactors have significantly less decay heat to deal with, since they do not trap the volatile fission products within a solid fuel. This reduces the difficulty of the problem from the outset. Furthermore, the drain tank is separate, contains no moderator, and can be optimized for passive decay heat removal--something not possible with solid fueled reactors.
Also, your graphite red herring is not only irrelevant, but false. This has been studied, and graphite does not burn in air. It requires specific conditions; the presence of water IIRC. Again, molten salt reactors will not be cooled by water, nor need they be constructed anywhere near the reach of tsunamis or floods. (Though, there are no active systems to fail anyway...) The floride salt and water reaction is also a red herring; the reaction proceeds so slowly that it poses no concern.
| will mechanically drain its operating fluid into a vessel where it will just sit there.
Until the rain and floods come in after the accident in which case you have steam explosions and radioactive waste in a highly water-soluble liquid combing to make all sorts of fun.
The salts are not water soluble, and have no violent reactions with either air or water. Contrary to your claims of "all sorts of fun", ORNL even dumped some in a pool at one point, and it did little more than create some steam. Fluoride salts are among the most chemically stable substances on earth, and both the fissile and fission products remain safely dissolved in just about any imaginable circumstances. Even so, keeping water out is not an issue, as there is no need to site the plants anywhere near water.
A LFTR is a chemical reprocessing plant with astonishingly racdioactive liquid (since it just came out of the fission core) circulating at hundreds of degrees with caustic chemical properties. There will be leaks. There will be breaches. Every drop is a huge problem. There will be----well anything that can go wrong in a hot chemical plant---now add in the fact that humans even in suits can't go in there for decades if something is wrong.
The sort of reprocessing done for a LFTR is very different and far simpler than conventional nuclear reprocessing, and the rates for continuous processing are also very modest. The entire reprocessing system will fit along with the core in a small hot cell. The most dangerous volatile fission products are continuously off-gassed, and do not build up as in solid fuels. Thus even in the event of an accident, there is a very small amount of residual radioactivity, and still no driving force to push it into the environment.
Nuclear reprocessing plants are the nastiest ones, because of the combination of liquids and radiaoactivity. I do not trust a utility with such an installation, and only want a tiny number of them, not every power plant to be one.
If the continuous processing bothers you, there are variations of molten salt reactors like the DMSR that leave all of the fission products dissolved in the salts, and only require processing every 10-30 years. By the tone of your post though, it sounds like you are only interested in fear mongering, and not rational discussion.