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Not enough attention is being paid to Japan's contrarian "red hydrogen" strategy. This entails using a novel helium cooled fission reactor to generate very hot

Not enough attention is being paid to Japan's contrarian "red hydrogen" strategy. This entails using a novel helium cooled fission reactor to generate very hot (950C, 1750F) process heat that is then fed into an Sulphur-Iodine cycle hydrogen plant to create very cheap hydrogen without any feedstock but air and water. Beyond fuel, hydrogen can be used to replace coal in iron smelting, Haber-Bosch fertilizer, and other chemical processes that require hydrogen made today via fossil fuels. They already have a 30MW pilot reactor in operation, and are just about to turn on the S-I hydrogen plant. Could be a very interesting addition to global energy mix. Strategy: https://www.csis.org/analysis/japans-hydrogen-industrial-strategy https://www.csis.org/analysis/japans-hydrogen-industrial-str... Reactor: https://www.world-nuclear-news.org/Articles/Japanese-gas-cooled-reactor-restarts https://www.world-nuclear-news.org/Articles/Japanese-gas-coo... S-I Process: https://en.wikipedia.org/wiki/Sulfur%E2%80%93iodine_cycle https://en.wikipedia.org/wiki/Sulfur%E2%80%93iodine_cycle Video (hypey): https://www.youtube.com/watch?v=_uTZWaJU6ho https://www.youtube.com/watch?v=_uTZWaJU6ho

jandrese 4y ago
"Very cheap" is definitely on the "I'll believe it when I see it" category.
- nickpinkston 4y ago
  Yea, totally. I'm saying it's a strategy, not a reality haha.
- PaulHoule 4y ago
  The high cost of Gen 3 nuclear power is largely due to the very large steam turbine and heat exchangers that are required if you are using water as a working fluid, coolant, and moderator. From the 1950s to the 1990s the interest in fast reactors has been in the 60x better fuel economy and reduced waste problem. (e.g. less radioactive than the uranium ore in 1000 years) It was believed back then that a fast reactor coupled to a steam turbine would have a higher capital cost than an LWR. There also was a lot of concern that it takes a lot of uranium or plutonium to form a critical mass and that would be an expense. Recently fast reactors and other high temperature reactor types are of interest because getting rid of the water could allow miniaturizing the whole system and get the cost competitive with natural gas not to mention solar and wind on the days that solar and wind feel like supplying power. The stockpile of plutonium in spent fuel is getting bigger and bigger every day and the public seems entirely uninterested in throwing away 98% of the energy content of the spent fuel away in a place like Yucca Mountain. Thus high-quality fissile material seems a lot less scarce than it did in the EBR I - Superphenix era.
jcampbell1 4y ago
There is a reason we run nuclear reactors at 400C rather than 1000C. I wish scientists could be called out for lies of omission. “A novel nuclear reactor which operates just below the temperature where our most exotic alloys mechanically fail”.
- HPsquared 4y ago
  Steam at 950°C and helium at 950°C are very, very different when it comes to corrosion and safety.
  - pfdietz 4y ago
    And vaporized sulfuric acid decomposed to SO2 + O2 + H2O at that temperature... how do you think that compares?
- kergonath 4y ago
  > There is a reason we run nuclear reactors at 400C rather than 1000C. There are several reactors design that work at high temperature, HTGR are not new. > A novel nuclear reactor which operates just below the temperature where our most exotic alloys mechanically fail We have plenty of materials that can withstand higher temperatures than that, both refractory alloys and ceramics. Do you know the temperature in an aircraft engine? If weight is not a factor, plain old tungsten melts at 3400°C.
  - robocat 4y ago
    > HTGR https://atomicinsights.com/chinas-high-temperature-reactor-pebble-bed-modular-htr-pm-achieves-its-first-criticality/ https://atomicinsights.com/chinas-high-temperature-reactor-p... has a summary of the past experimental reactors (skip half way down to the heading “Brief high temperature reactor history”), and explains some of the reasons past reactors have failed to be commercialised. It also explains one central problem with using gas: “Even with higher temperatures and higher efficiency, each core can produce 1/10th of the electricity of light water reactors, but [China’s] HTR pressure vessel is described as ‘the world’s largest and heaviest pressure vessel.’ Pressurized gas has a far lower capacity to move heat than pressurized water.”. https://duckduckgo.com/?q=high-temperature+gas+reactor https://duckduckgo.com/?q=high-temperature+gas+reactor
pfdietz 4y ago
Yeah, a chemical cycle involving vaporizing and decomposing sulfuric acid at 850 C is totally credible. Yes, let's avoid turbines and instead make our equipment out of ... tantalum? /s The maximum thermodynamic efficiency of this cycle is 50% (and likely will be lower). This is not much better than making electricity with the reactor and driving electrolysers. And when the levelized cost of energy from renewables is very low (especially for the surplus energy that could be fed into electrolysers as needed) it's hard to see how this scheme competes. Yes, it doesn't have turbines, but it does have all sorts of high temperature chemical reactors that must survive corrosive conditions.
- nickpinkston 4y ago
  I think the point is that we should try a lot of different approaches, as there may be good fits that aren't possible to do via electricity - ie is electro smelting iron > using hydrogen? Unsure we really know what that looks like at scale yet. Either way there's an unproven process step with lots of efficiency questions for plants at scale, and I'm impressed to see Japan seriously trying something totally different.
- anotherbadlogin 4y ago
- scythe 4y ago
  >The maximum thermodynamic efficiency of this cycle is 50% (and likely will be lower). This is not much better than making electricity with the reactor and driving electrolysers. The numbers I've found elsewhere dispute this. The World Nuclear Association puts the thermal -> electric conversion efficiency of nuclear plants at around 35% (current) to 40% (best) [1]. A similar but far less corrosive copper-chlorine process is being developed in Canada with preliminary analyses claiming as much as double the efficiency of electrolysis [2]. The maximum thermodynamic efficiency may also be exceeded if waste heat can be converted to electricity simultaneously. With that said, tests of the sulfur-iodine process continue to find that corrosion and damage to the (chemical) reactor components remains limiting, with 20% efficiency lost in H2SO4 splitting over just four days [3]. H2SO4 at 900 C is much more corrosive than HCl at 500 C. 1: https://world-nuclear.org/our-association/publications/technical-positions/cooling-of-power-plants.aspx https://world-nuclear.org/our-association/publications/techn... 2: https://www.sciencedirect.com/science/article/pii/S0360319922043555 https://www.sciencedirect.com/science/article/pii/S036031992... 3: https://www.sciencedirect.com/science/article/pii/S1364032117309231 https://www.sciencedirect.com/science/article/pii/S136403211...

jandrese 4y ago

"Very cheap" is definitely on the "I'll believe it when I see it" category.

nickpinkston 4y ago
Yea, totally. I'm saying it's a strategy, not a reality haha.
PaulHoule 4y ago
The high cost of Gen 3 nuclear power is largely due to the very large steam turbine and heat exchangers that are required if you are using water as a working fluid, coolant, and moderator. From the 1950s to the 1990s the interest in fast reactors has been in the 60x better fuel economy and reduced waste problem. (e.g. less radioactive than the uranium ore in 1000 years) It was believed back then that a fast reactor coupled to a steam turbine would have a higher capital cost than an LWR. There also was a lot of concern that it takes a lot of uranium or plutonium to form a critical mass and that would be an expense. Recently fast reactors and other high temperature reactor types are of interest because getting rid of the water could allow miniaturizing the whole system and get the cost competitive with natural gas not to mention solar and wind on the days that solar and wind feel like supplying power. The stockpile of plutonium in spent fuel is getting bigger and bigger every day and the public seems entirely uninterested in throwing away 98% of the energy content of the spent fuel away in a place like Yucca Mountain. Thus high-quality fissile material seems a lot less scarce than it did in the EBR I - Superphenix era.

jcampbell1 4y ago

There is a reason we run nuclear reactors at 400C rather than 1000C. I wish scientists could be called out for lies of omission. “A novel nuclear reactor which operates just below the temperature where our most exotic alloys mechanically fail”.

HPsquared 4y ago
Steam at 950°C and helium at 950°C are very, very different when it comes to corrosion and safety.
- pfdietz 4y ago
  And vaporized sulfuric acid decomposed to SO2 + O2 + H2O at that temperature... how do you think that compares?
kergonath 4y ago
> There is a reason we run nuclear reactors at 400C rather than 1000C. There are several reactors design that work at high temperature, HTGR are not new. > A novel nuclear reactor which operates just below the temperature where our most exotic alloys mechanically fail We have plenty of materials that can withstand higher temperatures than that, both refractory alloys and ceramics. Do you know the temperature in an aircraft engine? If weight is not a factor, plain old tungsten melts at 3400°C.
- robocat 4y ago
  > HTGR https://atomicinsights.com/chinas-high-temperature-reactor-pebble-bed-modular-htr-pm-achieves-its-first-criticality/ https://atomicinsights.com/chinas-high-temperature-reactor-p... has a summary of the past experimental reactors (skip half way down to the heading “Brief high temperature reactor history”), and explains some of the reasons past reactors have failed to be commercialised. It also explains one central problem with using gas: “Even with higher temperatures and higher efficiency, each core can produce 1/10th of the electricity of light water reactors, but [China’s] HTR pressure vessel is described as ‘the world’s largest and heaviest pressure vessel.’ Pressurized gas has a far lower capacity to move heat than pressurized water.”. https://duckduckgo.com/?q=high-temperature+gas+reactor https://duckduckgo.com/?q=high-temperature+gas+reactor

pfdietz 4y ago

Yeah, a chemical cycle involving vaporizing and decomposing sulfuric acid at 850 C is totally credible. Yes, let's avoid turbines and instead make our equipment out of ... tantalum? /s The maximum thermodynamic efficiency of this cycle is 50% (and likely will be lower). This is not much better than making electricity with the reactor and driving electrolysers. And when the levelized cost of energy from renewables is very low (especially for the surplus energy that could be fed into electrolysers as needed) it's hard to see how this scheme competes. Yes, it doesn't have turbines, but it does have all sorts of high temperature chemical reactors that must survive corrosive conditions.

nickpinkston 4y ago
I think the point is that we should try a lot of different approaches, as there may be good fits that aren't possible to do via electricity - ie is electro smelting iron > using hydrogen? Unsure we really know what that looks like at scale yet. Either way there's an unproven process step with lots of efficiency questions for plants at scale, and I'm impressed to see Japan seriously trying something totally different.
anotherbadlogin 4y ago
scythe 4y ago
>The maximum thermodynamic efficiency of this cycle is 50% (and likely will be lower). This is not much better than making electricity with the reactor and driving electrolysers. The numbers I've found elsewhere dispute this. The World Nuclear Association puts the thermal -> electric conversion efficiency of nuclear plants at around 35% (current) to 40% (best) [1]. A similar but far less corrosive copper-chlorine process is being developed in Canada with preliminary analyses claiming as much as double the efficiency of electrolysis [2]. The maximum thermodynamic efficiency may also be exceeded if waste heat can be converted to electricity simultaneously. With that said, tests of the sulfur-iodine process continue to find that corrosion and damage to the (chemical) reactor components remains limiting, with 20% efficiency lost in H2SO4 splitting over just four days [3]. H2SO4 at 900 C is much more corrosive than HCl at 500 C. 1: https://world-nuclear.org/our-association/publications/technical-positions/cooling-of-power-plants.aspx https://world-nuclear.org/our-association/publications/techn... 2: https://www.sciencedirect.com/science/article/pii/S0360319922043555 https://www.sciencedirect.com/science/article/pii/S036031992... 3: https://www.sciencedirect.com/science/article/pii/S1364032117309231 https://www.sciencedirect.com/science/article/pii/S136403211...