Building LFTRs

[starcanuck64]

http://energyfromthorium.com/essay3rs/

Liquid-Fluoride Thorium Reactors seem to offer a significant advantage over Uranium Oxide fueled light water reactors in terms of efficiency, safety and waste output,

I was wondering what are some of the technical issues that have to be overcome before LFTRs are ready for commerical use?

[John Jaksich]

Toxicity would be one standard and to ensure that none of it seeped into the water table--it is "somewhat" common knowledge this source of energy is promising.


From Wikipedia:
"Canada, Germany, India, Netherlands, the United Kingdom and the United States have experimented with using thorium as a substitute nuclear fuel in nuclear reactors. There is a growing interest in developing a thorium fuel cycle due to its safety benefits, absence of non-fertile isotopes, and its higher occurrence and availability when compared to uranium. India's three stage nuclear power programme is possibly the most well known and well funded of such efforts.
"

I eliminated other footnotes within the citation---but they should be readily available.

[Antice]

Toxicity would be one standard and to ensure that none of it seeped into the water table--it is "somewhat" common knowledge this source of energy is promising.


From Wikipedia:
"Canada, Germany, India, Netherlands, the United Kingdom and the United States have experimented with using thorium as a substitute nuclear fuel in nuclear reactors. There is a growing interest in developing a thorium fuel cycle due to its safety benefits, absence of non-fertile isotopes, and its higher occurrence and availability when compared to uranium. India's three stage nuclear power programme is possibly the most well known and well funded of such efforts.
"

I eliminated other footnotes within the citation---but they should be readily available.

Why did you just fetch that from wikipedia? the part you fetched are not even relevant to Molten salt based reactors at all.

LFTR is not a standard reactor as most people known them.
It has it's fuel disolved in molten FliBe salt.

Since the fuel is already in a liquid state this allows for a whole host of novel methods and processes to be done while the reactor is running. Like on the fly fuel reprocessing and refueling. it runs at a pretty high temperature as well, so thermal efficiency can become pretty good.

The biggest challenge for LFTR is that it tries to add both a high efficiency somewhat uncommon steam cycle and online reprocessing/refueling to what is essentially a very unique type of reactor. All at the same time.
It has been suggested that the online refuel/reprocessing makes the project a bit too ambitious, and that one should go with a stopgap design like the Denatured Molten Salt Reactor instead. Nobody who actually wants to do Molten Salt reactor Development seem to go for that option tho. (The main contestants for LFTR would be the US based Flibe Energy, and a chinese national lab.)

Att this stage of development (that is almost no hardware built at all) it all seem very promising. But I think that things will crop up once development starts to get underway for real. we can only cross our fingers and wait for results.

One thing that we should not do however is hold out on building classic nuclear while we wait. LFTR need at least a decade or more before it is ready for prime time.

[John Jaksich]

Why did you just fetch that from wikipedia? the part you fetched are not even relevant to Molten salt based reactors at all.

LFTR is not a standard reactor as most people known them.
It has it's fuel disolved in molten FliBe salt.

Since the fuel is already in a liquid state this allows for a whole host of novel methods and processes to be done while the reactor is running. Like on the fly fuel reprocessing and refueling. it runs at a pretty high temperature as well, so thermal efficiency can become pretty good.

The biggest challenge for LFTR is that it tries to add both a high efficiency somewhat uncommon steam cycle and online reprocessing/refueling to what is essentially a very unique type of reactor. All at the same time.
It has been suggested that the online refuel/reprocessing makes the project a bit too ambitious, and that one should go with a stopgap design like the Denatured Molten Salt Reactor instead. Nobody who actually wants to do Molten Salt reactor Development seem to go for that option tho. (The main contestants for LFTR would be the US based Flibe Energy, and a chinese national lab.)

Att this stage of development (that is almost no hardware built at all) it all seem very promising. But I think that things will crop up once development starts to get underway for real. we can only cross our fingers and wait for results.

One thing that we should not do however is hold out on building classic nuclear while we wait. LFTR need at least a decade or more before it is ready for prime time.

I don't take issue with any of what you said--my issue is based upon already existing problems of the manner in which "waste" is handled.

Much agricultural land has a dwindling fresh water problem---There is also the problem of well water sources being polluted beyond a point of being potable.

Furthermore, I do believe in technology having the potential of solving our problems, but there are those who can not learn to use it within its capabilities.

[starcanuck64]

One thing that we should not do however is hold out on building classic nuclear while we wait. LFTR need at least a decade or more before it is ready for prime time.

A decade doesn't sound too bad, hopefully whatever issues do crop up will be solvable.

LFTRs sound like a simpler option than some of the Generation IV fast reactors where reactor control is going to be a challenge, from what I understand the design of the reactor itself is one of the more important elements.

If LFTRs become practical they can fill a lot of the potential of fast neutron reactors in converting the stockpiles of nuclear waste into less long lived products. Plus you can remove all the Xenon, Neodymium and other fission byproducts that can be sold commercially, you were mentioning how that may be possible online, which would be a big step up from processing solid fuel bundles.

[neilzero]

To do it fast track, we need to guess which are the best ten detailed designs, and fund all of them. As we learn, we will likely have to modify the designs at least slightly. At completion perhaps none of the ten will be competitive with average nuclear power plants, but hopefully we will know how to make the next ten cost effective. Neil

[starcanuck64]

This is an important factor when looking at LFTRs for future power production.

http://energyfromthorium.com/2010/05...ke-of-psrieer/

j) The 8th paragraph is singularly misleading, because there’s no “spent fuel” in an MSR – all Th232 & U233 are consumed, and there’s never a scheduled shutdown for refueling, because of the very nature of the design – an unpressurized,liquid. ThF4 or UF4 (or even higher U & Pu isotopes as salts) are simply added into the molten mix as it’s pumped around the reactor & heat-exchanger plumbing. It’s what every chemist understands & loves: liquid, unpressurized chemistry. And, since all fuel is consumed, an MSR can be used to reduce nuclear wastes down to any level desired, even on the site of a de-commissioned U/Pu reactor. This is exactly the kind of ability responsible scientists, engineers, doctors, politicians and citizens care about. PSR/IEER proliferation of this paper hides what is perhaps the most important knowledge we need today to pursue a weapons-free world — MSRs can consume them all. Why the authors say nothing of this deserves intense scrutiny. For details…

[Antice]

This is exactly why building out gen 3 reactors today makes so much sense. once we get a molten salt based reactor going then all that "spent" fuel becomes an already stored on site fuel for any later added MSR's. you could easily keep running those gen 3 boilers until their designed end of life without any major added economic cost that way.

[starcanuck64]

On reading up on LFTRs there is some question of them being a proliferation risk.

From what I understand the main claim against this is the presence of a small amount of U-232 which is produced as the Th-233 decays to Pa-233 then to U-233. U-232 produces highly radioactive fission products which emit gamma radiation making processing much more difficult and easier to detect radiological materials that may be attempted to be smuggled.

Also you can make a nuclear weapon out of U-233, but the radiation from the U-232 produced with the U-233 in an LFTR and its products would fry the technicians making it and the electronics and other equipment used to detonate it. Also if you remove the U-233 midstream from the fuel cycle it will cause the reactor to stop functioning. You could leave the U-233 to cook down to a purer state but that would take years.

So is there a credible proliferation risk with LFTRs?

[Antice]

On reading up on LFTRs there is some question of them being a proliferation risk.

From what I understand the main claim against this is the presence of a small amount of U-232 which is produced as the Th-233 decays to Pa-233 then to U-233. U-232 produces highly radioactive fission products which emit gamma radiation making processing much more difficult and easier to detect radiological materials that may be attempted to be smuggled.

Also you can make a nuclear weapon out of U-233, but the radiation from the U-232 produced with the U-233 in an LFTR and its products would fry the technicians making it and the electronics and other equipment used to detonate it. Also if you remove the U-233 midstream from the fuel cycle it will cause the reactor to stop functioning. You could leave the U-233 to cook down to a purer state but that would take years.

So is there a credible proliferation risk with LFTRs?

Sure is. the LFTR can be made small enough to not only power a destroyer class vessel adequately, it can give it enough surplus juice to employ high power directed energy weapons like THEL lasers and railguns.
Guess the glory days of the airforce can be kissed goodbye if that ever happens. Them Lasers if given enough juice can fully deny airspace from horizon to horizon.

As far as making bombs with it. forget it. it's much easier/cheaper to use uranium 238 targets and breed some plutonium instead. much easier to make a bomb out of plutonium. (still so expensive that apart from the political scare factor they are indeed not really worth it).
The second objection against proliferation arguments, is the fact that these reactors are not being developed by non nuclear capable nations. the players capable of making the LFTR happen already got more nukes than they know what to do with. the LFTR's may even get their startup charges from decommissioned nuclear bombs. Now how's that for swords to plowshares?

[Ara Pacis]

Sure is. the LFTR can be made small enough to not only power a destroyer class vessel adequately, it can give it enough surplus juice to employ high power directed energy weapons like THEL lasers and railguns.
Guess the glory days of the airforce can be kissed goodbye if that ever happens. Them Lasers if given enough juice can fully deny airspace from horizon to horizon.

I'd like to see a laser that could punch through that much atmosphere and still have enough energy to damage military hardware in a useful manner.

As far as making bombs with it. forget it. it's much easier/cheaper to use uranium 238 targets and breed some plutonium instead. much easier to make a bomb out of plutonium. (still so expensive that apart from the political scare factor they are indeed not really worth it).
The second objection against proliferation arguments, is the fact that these reactors are not being developed by non nuclear capable nations. the players capable of making the LFTR happen already got more nukes than they know what to do with. the LFTR's may even get their startup charges from decommissioned nuclear bombs. Now how's that for swords to plowshares?

And then we get wiped out from an asteroid that we could have stopped with nukes or nuke-pulse propulsion. Thanks.

[Antice]

I'd like to see a laser that could punch through that much atmosphere and still have enough energy to damage military hardware in a useful manner.



And then we get wiped out from an asteroid that we could have stopped with nukes or nuke-pulse propulsion. Thanks.

The ABL seems to do a good job on missiles as it is. THEL lasers mounted on a decently sized vessel can have several orders of magnitude more oomph in them than those chemical lasers they have wrapped that big airplane around. not only that. but we have adaptive optics to help compensate as well. Fear not. Death-rays from below(tm) are coming to a port near you soon.

Now that asteroid. I never said we should decommission all the nukes. they do have their uses, but discussing some of those uses don't fit on this forum imho. Asteroids is a problem we do need to come up with a system for, and it may/may not include the use of nuclear warheads. there are many options, and i do feel that too little is being done in this field still.
We do however have more nukes than we need on this here planet. waaay more than we need. so we might as well try to do something positive with all that high grade fuel just sitting around waiting for doomsday.

[starcanuck64]

Sure is. the LFTR can be made small enough to not only power a destroyer class vessel adequately, it can give it enough surplus juice to employ high power directed energy weapons like THEL lasers and railguns.
Guess the glory days of the airforce can be kissed goodbye if that ever happens. Them Lasers if given enough juice can fully deny airspace from horizon to horizon.

As far as making bombs with it. forget it. it's much easier/cheaper to use uranium 238 targets and breed some plutonium instead. much easier to make a bomb out of plutonium. (still so expensive that apart from the political scare factor they are indeed not really worth it).
The second objection against proliferation arguments, is the fact that these reactors are not being developed by non nuclear capable nations. the players capable of making the LFTR happen already got more nukes than they know what to do with. the LFTR's may even get their startup charges from decommissioned nuclear bombs. Now how's that for swords to plowshares?

I wasn't really thnking of the military uses(more rogue states building crude nukes), but having a reactor that isn't pressurized and only needs a fraction of the space to work compared to LWRs does open up a whole new dimension when it comes to high energy weapons.

Not just ship but land based lasers could replace SAMs in the future.

[Ara Pacis]

The ABL seems to do a good job on missiles as it is. THEL lasers mounted on a decently sized vessel can have several orders of magnitude more oomph in them than those chemical lasers they have wrapped that big airplane around. not only that. but we have adaptive optics to help compensate as well. Fear not. Death-rays from below(tm) are coming to a port near you soon.

for some reasons I thought the COIL on the ABL was more powerful than what was used on the THEL. Or maybe it has to do with the usage, CW or Pulsed, like a PIKL. My bid idea is to put them on large airships and use them for sea and border patrol as strategic ABM pickets and fleet missile pickets and domestic-international anti-smuggling patrols. Although the later might not need to be laser armed, it might help with submersibles that surface for a short time or with really fast speedboats (although bombs and missiles might work as well or better).

Now that asteroid. I never said we should decommission all the nukes. they do have their uses, but discussing some of those uses don't fit on this forum imho. Asteroids is a problem we do need to come up with a system for, and it may/may not include the use of nuclear warheads. there are many options, and i do feel that too little is being done in this field still.
We do however have more nukes than we need on this here planet. waaay more than we need. so we might as well try to do something positive with all that high grade fuel just sitting around waiting for doomsday.

Even if we don't use nukes as weapons, we might get a gravity tractor or a NSWR-outboard-motor in position sooner.

I wasn't really thnking of the military uses(more rogue states building crude nukes), but having a reactor that isn't pressurized and only needs a fraction of the space to work compared to LWRs does open up a whole new dimension when it comes to high energy weapons.

Not just ship but land based lasers could replace SAMs in the future.

Except that SAMs are not limited to Line-of-Sight. They might even be launched before sighting on distant early warning and seek out the target once airborne.

[Antice]

The chemical reactions are pretty comparable in relation to power/mass i think. so the main difference is size. THEL has to be road vehicle mobile, and so it needs to use it's power more efficiently. Pulsing the laser may help with that since it allows vaporized metal to disperse a bit before the next pulse hits. the fact that the reaction used in THEL is better at going trough air also helps a bit.

However. once you have huge loads of electrical power available then you won't be using chemicals for making the laser light any more. my favored tech is the Free electron Laser. it's a highly tune-able laser that can deliver it's light within a pretty broad spectrum. the best part is. given a compact enough power source it can be fairly small. altho quite heavy.
In retrospect i don't think neither the ABL nor the THEL are all that close to describing how a LFTR powered laser defense system would look. it would be too heavy to be airborne in anything short of a nuclear powered blimp, and too bulky for anything that could pass under/over any reasonably built bridge.
Maybe if polywell ends up working as advertised, and they manage to miniaturize it enough trough the use of high temp superconductors, then maybe we could get a Hammers slammers hover-tank tank going. The US Navy most certainly do seem awfully interested in polywell tho.

Back to LFTR: It's best use is going to be to replace fossil fuels for electricity generation, as well as potentially mass production of medical isotopes and other rather useful goodies. I'd have to say that no matter how fascinating the military implications of such a dense power source is, i really am more excited about the civilian ones.

[starcanuck64]

Maybe if polywell ends up working as advertised, and they manage to miniaturize it enough trough the use of high temp superconductors, then maybe we could get a Hammers slammers hover-tank tank going.

You know you're getting old when the SF you read in youth becomes current technology.

Back to LFTR: It's best use is going to be to replace fossil fuels for electricity generation, as well as potentially mass production of medical isotopes and other rather useful goodies. I'd have to say that no matter how fascinating the military implications of such a dense power source is, i really am more excited about the civilian ones.

I think there's only a few places that produce radioactive isotopes for medical use now, LFTRs will constantly produce things like Iodine-131 and Bismuth-213 which can also be removed online. It should help make nuclear medicine much more accessable and affordable.

[Antice]

You know you're getting old when the SF you read in youth becomes current technology.

Well... being an old cavalryman myself i kinda fell in love with the equipment described in the hammer series. but i'm not all that old yet.. just getting into my middle thirties.

I think there's only a few places that produce radioactive isotopes for medical use now, LFTRs will constantly produce things like Iodine-131 and Bismuth-213 which can also be removed online. It should help make nuclear medicine much more accessable and affordable.

This is one of the things i am really excited about. There are so many uses for radioisotopes in medicine. Some uses that are just now being invented as well. like targeted radiation therapy for curing even more types of cancer than ever before.

[starcanuck64]

This is one of the things i am really excited about. There are so many uses for radioisotopes in medicine. Some uses that are just now being invented as well. like targeted radiation therapy for curing even more types of cancer than ever before.

We've been conditioned to see any radiation exposure as harmful but there's evidence that the opposite may be the case. Low doses of radiation may have positive health benefits by stimulating the immune system and making it more able to deal with things like cancer.

By directly delivering Bismuth-213 to tumors they can effectively be destroyed.

http://atomicinsights.com/2011/05/ho...l-effects.html

[Ivan Viehoff]

The main problem is that such a level of technical innovation is very risky, and it all tends to end up taking a lot longer and costing a lot more than people expected. Look at that reactor under construction in Finland, such a small development of the existing PWR it couldn't possibly go wrong, yet it is going to cost twice the budget and take twice as long. The Chinese apparently built one to time and budget, but no doubt they papered over the cracks.

This is a much greater step of innovation. In such cases, you come across problems you didn't antipate, which then take further innovation to fix. This includes bureaucratic problems (look how expensive the bureaucratic decision to double the number of escape cross-tunnels was for Eurotunnel) as well as technical problems.

The company's website is completely silent on who is funding them and how much money they have got to spend.

[starcanuck64]

LFTRs are a simplification of current reactor designs, I'm not sure how that's going to create difficult design issues.

Molten salt reactors run at near normal pressures so they don't require the very extensive and expensive containment that PWRs do. In a catastrophic failure of a LFTR where the core vessel was ruptured the molten salt carrying the fuel fills the outer vessel, melts a frozen salt plug and drains into passively cooled holding vessels. No explosive release of radioactive steam results.

They do operate at higher temperatures than current designs and that will require developing the right alloys to use, I think Hastelloy with a titanium content was proved suitable back in the 1960s in the ORNL program.

A lot of the baseline R&D has already been done, the first MSRs were up and running in the mid 1950s under the airborne reactor program.

[Ivan Viehoff]

LFTRs are a simplification of current reactor designs, I'm not sure how that's going to create difficult design issues.

Go back and read post #3 then. Whenever you go somewhere rather different from where anyone else has ever been before, the unexpected problems pop up, and they always cost a lot to solve. That PWR being built in Finland was supposed to be straightforward, but it turns out it wasn't. This thinking something is straightforward when we know that these kind of projects always have big problems is called "optimism bias". The UK govt requires planners to add 60% to the forecast cost of public works which have incomplete specs, and this is just for stuff like buildings and roads. In the case of something like a new nuclear reactor design, 200% wouldn't be a silly number.

[starcanuck64]

Go back and read post #3 then. Whenever you go somewhere rather different from where anyone else has ever been before, the unexpected problems pop up, and they always cost a lot to solve. That PWR being built in Finland was supposed to be straightforward, but it turns out it wasn't. This thinking something is straightforward when we know that these kind of projects always have big problems is called "optimism bias". The UK govt requires planners to add 60% to the forecast cost of public works which have incomplete specs, and this is just for stuff like buildings and roads. In the case of something like a new nuclear reactor design, 200% wouldn't be a silly number.

Certainly there are going to be challenges in designing the right blend of features into commercial LFTRs. The basic R&D already done indicates the very real benefits to doing so.

The basic design is simpler, more efficient and safer than conventional LWR designs we have now. Once you solve the design issues around running at higher tempertures, removing nuclear poisons like Xenon-135 and commericially valuable isotopes online then you create an almost entirely new market. I don't think it's a pipe dream to see the future of Thorium based MSRs as being very bright.

And having a private company like Flibe doing it's own design and development may avoid some of the pitfalls that can occure in projects like this, just as companies like SpaceX are offering different options of transporting payload into orbit.

I'm not sure where you were going by raising the funding issue earlier, is there something wrong with private individuals and companies developing new energy technology?

[Ara Pacis]

Why so much concern for R&D costs? We pretty much know it works. So, it may cost more for the first one to work the bugs out, but after that, it's just repetition of the design.

[starcanuck64]

The case isn't that LFTRs hit unsolvable issues back in the early 1970s, the reality is due to political priorities at the time it was seen as a backup to Liquid Melt Fast Breeder Reactors. Funding for the MSRE(Molten Salt Reactor Experiment) at ORNL was cut in 1973 in favor of the LMFBR program. They did build and run MSRs for several years and found that Thorium provided the best fuel cycle.

I remembered the issue with brittle Hastelloy incorrectly, it was due to the fission product tellurium.

http://energyfromthorium.com/2012/06...-news-article/

The breeder development work in ORNL’s MSR program ran into a snag in 1971 when it was discovered that surface cracking was taking place in Hastelloy-N, the nickel-base alloy in the reactor vessel and heat exchanger tubes.

It was later found that tellurium, one of numerous fission products, was causing the cracking. Last year ORNL engineers learned that, by adding titanium to the Hastelloy-N, both the cracking problem and radiation embrittlement of Hastelloy-N could be licked.

There's several decades of R&D to build on with new more capable designs, plus forty years of advancement in material and theoretical science.

[Ivan Viehoff]

I'm not sure where you were going by raising the funding issue earlier, is there something wrong with private individuals and companies developing new energy technology?

Unfortunately there has been rather frequently, which I hoped you might spot without the need for me to spell it out. There are an awful lot of scams around of varying sophistication to extract money from the gullible under the name of product development for wonderful new energy generation methods. Of course most of them are fairly obviously fake, like cold fusion, zero-point energy devices, and running your car on water. But others are actually appear like trying to achieve the genuinely achievable, and appeal to different emotions to take people's money without sufficent mechanism to be assured that the money will be applied to the purpose intended, like the purported rescues of Rover Cars* and Glasgow Rangers Football Club**, and the setting up of the DeLorean Motor Company (to name some British examples, as these are best known to me.) That's why I was looking on their website for any evidence of reputable backers, (though in the case of the Rover Cars and DeLorean scams, the mark was the British Government) or tangible output, but I only found what I might call "marketing papers". There are some hints places of military connections, and Huntsville Al is a likely location for a company with such connections, but again no solid evidence of military funding I could find.

*A brilliant scam, they didn't even have to do anything illegal. The four lucky people who were given the company for free just paid themselves multi-million pound salaries out of short term funds, and kept it going for long enough they could laugh all the way to the bank when the company went massively bankrupt a couple of years later. The subsequent enquiry correctly blamed it on the gullibility of the government.

**Unfortunately failing football (soccer) clubs are a wonderful vehicle for the dishonest to get their claws into, because they tend to have a high up-front cash turnover the dishonest can fill their pockets from, while avoiding paying the bills and letting the liabilities build up even more. Many more cases can be mentioned, but Rangers is good to cite as there is solid evidence of dishonest actions there. The guy maximised his pocket-filling by mortgaging the future season ticket income.

[starcanuck64]

I'm thinking that Flibe is getting backing from some deep pockets of the Elon Musk or Paul Allen kind, but it's hard to know.

The science looks pretty solid behind molten salt reactors and their future applications but "buyer beware" is always a good philosophy.

If and when Flibe goes public, it will have to open it's financial records up so that should remove a lot of the uncertainty. It could also be that energy sector heavyweights like Southern or other companies are involved in backing Sorensen and his group.

[starcanuck64]

Looks like there are a number of different projects in the works to get Thorium fuel cycle reactors producing power.

http://en.wikipedia.org/wiki/Liquid_...r#The_Fuji_MSR

[starcanuck64]

So from what I've been able to gather, 1 ton of thorium in a molten salt reactor gives about 1 Gigawatt years of power.

I think I read in another thread a post by Ara Pacis that the US requirement was about 86 Gwy/y and US reserves of thorium are around 400,000 tons which by my rough calculations would give over 3,000 years of energy at current demands.

http://en.wikipedia.org/wiki/Thorium

Also there was a molten salt reactor program that ran at ORNL for years that tested different fuels in a single stage reactor that didn't produce electricity.

http://en.wikipedia.org/wiki/Molten-...tor_Experiment

Statistics
Other operational statistics:[16]
Hours critical: 17,655
Circulating fuel loop hours: 21,788
Core volume: less than 2 m3

U-235 fuel operation
Critical June 1, 1965
Full power May 23, 1966
End operation March 26, 1968
Equivalent full power hours: 9,005

U-233 fuel operation
Critical October 2, 1968
Full power January 28, 1969
Reactor shutdown December 12, 1969
Equivalent full power hours: 4,167

So much of the baseline development has already been done, the MSRE didn't utilize a breeder blanket like the new designs are developing, at the time it was thought the plumbing would be too complex, that has since been changed.

[starcanuck64]

Wow, ask a simple question about meltdown risk of LFTRs and it turns into a very detailed discussion on how to deal with decay heat in the event of a catastrophic failure that removes the active cooling.

Not that I understood more than a fraction of what was being debated on the Energy From Thorium forum, but there's some interesting issues involved. Once the reactor is shut down and the fission of the U-233/U-232 stops the decay of the fission products continues with a peak in the first day producing heat that needs to be removed. During operation the main heat exchange loop is the main route of heat removal and once that is stopped from active function there needs to be a way to remove the heat from decaying isotopes.

A few of the ideas so far.

- Place the main reactor vessel in a buffer salt bath and have that salt at a lower temperature than the core salt loop but still in a molten state. You could suspend the core vessel with seismically isolated supports to protect it from earthquake damage.

- Also there is some discussion about natural convection within the primary and secondary heat exchange that could be used to cool the reactor down, but that was a bit too detailed for me.

- A multi-layer containment system, with a corrugated layer of Hastelloy-N in the middle to increase thermal conductivity and cooling of the primary reactor loop. This would have a relatively thin inner vessel, the corrugated sandwich and a slightly stronger outer layer for strength, with buffer salt flowing between the inner and outer layers by natural convection.

There's a lot of issues they need to work out to get LFTRs onto a commercially ready footing. One is the need for almost pure Lithium-7(99.9%) for use in the blanket and reactor loop molten salt, also I think there's a shortage of the Beryllium needed as a moderator in the salt. I'm not sure why the Li-7 is needed instead of Li-6, maybe someone here can explain it.

[TooMany]

The main problem is that such a level of technical innovation is very risky, and it all tends to end up taking a lot longer and costing a lot more than people expected. Look at that reactor under construction in Finland, such a small development of the existing PWR it couldn't possibly go wrong, yet it is going to cost twice the budget and take twice as long. The Chinese apparently built one to time and budget, but no doubt they papered over the cracks.

This is a much greater step of innovation. In such cases, you come across problems you didn't antipate, which then take further innovation to fix. This includes bureaucratic problems (look how expensive the bureaucratic decision to double the number of escape cross-tunnels was for Eurotunnel) as well as technical problems.

The company's website is completely silent on who is funding them and how much money they have got to spend.

Risky? The cost of development of new nuclear reactor designs pales in comparison with what we are spending to secure access to oil through military action. The argument that nuclear power is not cost effective comes from those who irrationally fear nuclear power or make their living from fossil fuels.

The last decade of military spending could have built 1,700 reactors at 4 billion dollars each (far more than we need). With nuclear electrical energy and serious infrastructure work we could build an electric road system. Cars and trucks could have batteries sufficient for short trips, say 20 miles (technology that already exists). On the major roads, electrical power could be delivered directly to vehicles by overhead wires or road-level rail. That would virtually remove our dependence on oil and allow us to use the domestic supplies for the chemical industry instead of making CO2. We could also stop burning coal, stop tearing up the countryside and virtually eliminate air pollution. Such a project could employ nearly everyone. But nooo...

Our problems are not technological, they are social.

The LFTR seems like an excellent idea. Doubtless problems will be encountered and have to be overcome, but the inherent safety and simplicity plus the thermal and fuel efficiency the approach offers should be plenty of motivation. Unfortunately I don't think that there will be sufficient political will until the oil situation becomes a crisis over the next couple of decades.

Rant over...