1/16
A significant achievement worth noting - China is reporting that it has almost completed its first experimental 2MW Thorium Molten Salt Reactor (MSR) in Gansu.
This article has more details, but I will try to provide a layman's background too.
livescience.com/china-creates-…
A significant achievement worth noting - China is reporting that it has almost completed its first experimental 2MW Thorium Molten Salt Reactor (MSR) in Gansu.
This article has more details, but I will try to provide a layman's background too.
livescience.com/china-creates-…
2/16
First - why Thorium (Th) and not Uranium (U)?
Th is more abundant in nature than U. In its most common natural state (Th-232) thorium is fertile, but not fissile.
That means it's stable, but it COULD be used to generate power via fission if hit by high-energy neutrons.
First - why Thorium (Th) and not Uranium (U)?
Th is more abundant in nature than U. In its most common natural state (Th-232) thorium is fertile, but not fissile.
That means it's stable, but it COULD be used to generate power via fission if hit by high-energy neutrons.
3/16
The Th fuel cycle relies on the fact that Th-232 eventually transmutes into U-233 when hit with those high-energy neutrons I mentioned (usually called 'fast neutrons').
U-233 IS fissile, and can be used for a sustained fission reaction. Presto, we have heat (ergo power).
The Th fuel cycle relies on the fact that Th-232 eventually transmutes into U-233 when hit with those high-energy neutrons I mentioned (usually called 'fast neutrons').
U-233 IS fissile, and can be used for a sustained fission reaction. Presto, we have heat (ergo power).
4/16
(For the physics nerds out there, there are actually two intermediary steps between Th-232 and U-233, namely Th-233 and Pa-233, both of which undergo beta decay to arrive at U-233).
(For the physics nerds out there, there are actually two intermediary steps between Th-232 and U-233, namely Th-233 and Pa-233, both of which undergo beta decay to arrive at U-233).
5/16
So it seems our main barrier to using Th-232 as a fuel for fission reactions is....how to generate and control “fast neutrons” to unlock the potential energy of Thorium?
This is where the "molten salt" part of the reactor comes into play.
So it seems our main barrier to using Th-232 as a fuel for fission reactions is....how to generate and control “fast neutrons” to unlock the potential energy of Thorium?
This is where the "molten salt" part of the reactor comes into play.
6/16
Dissolving the fuel element into a liquid salt mixture to serve as the neutron moderator (instead of light water, as most fission reactors use) ensures the excess neutrons released during fission are "fast neutrons".
Liquid salt reactors are a pathway to "fast neutrons".
Dissolving the fuel element into a liquid salt mixture to serve as the neutron moderator (instead of light water, as most fission reactors use) ensures the excess neutrons released during fission are "fast neutrons".
Liquid salt reactors are a pathway to "fast neutrons".
7/16
Almost all next-gen reactor designs are focused on generating fast neutrons so we can unlock the energy potential of fertile elements like Th or natural uranium. Most nuclear power-using countries have at least one next-gen project.
China has at least three.
Almost all next-gen reactor designs are focused on generating fast neutrons so we can unlock the energy potential of fertile elements like Th or natural uranium. Most nuclear power-using countries have at least one next-gen project.
China has at least three.
8/16
Besides the thorium MSR, China also has a liquid sodium reactor under construction in Xiapu and a high-temperature gas reactor in Shidaowan.
TOTALLY different technologies and approaches, but all have a similar goal: fast neutron fuel cycles.
Besides the thorium MSR, China also has a liquid sodium reactor under construction in Xiapu and a high-temperature gas reactor in Shidaowan.
TOTALLY different technologies and approaches, but all have a similar goal: fast neutron fuel cycles.
9/16
Theoretical benefits of the thorium fuel cycle include much more abundant fuel and lower proliferation risk.
The waste elements generated (mostly U-233) are also much easier to deal with than those from the U-235 fuel cycle (Plutonium).
Theoretical benefits of the thorium fuel cycle include much more abundant fuel and lower proliferation risk.
The waste elements generated (mostly U-233) are also much easier to deal with than those from the U-235 fuel cycle (Plutonium).
10/16
Remember, China has relatively weak uranium reserves but a LOT of thorium. This makes leaning into nuclear a significant energy security concern.
Replacing imported coal with imported uranium is much better for the environment, but hardly an improvement in energy security.
Remember, China has relatively weak uranium reserves but a LOT of thorium. This makes leaning into nuclear a significant energy security concern.
Replacing imported coal with imported uranium is much better for the environment, but hardly an improvement in energy security.
11/16
Disadvantages of the thorium fuel cycle:
- Fast neutron reactors are HARD to design. Liquid sodium burns or explodes when it touches..nearly everything. Molten salts absoutely eat metal piping (corrosive).
They are super expensive when they fail:
en.wikipedia.org/wiki/Superph%C…
Disadvantages of the thorium fuel cycle:
- Fast neutron reactors are HARD to design. Liquid sodium burns or explodes when it touches..nearly everything. Molten salts absoutely eat metal piping (corrosive).
They are super expensive when they fail:
en.wikipedia.org/wiki/Superph%C…
12/16
Also like any reactor relying on fertile material, the thorium fuel cycle relies on a highly enriched 'firestarter' to provide the initial fast neutrons.
So yes, the thorium fuel cycle requires use of highly-enriched uranium. China has not resolved this constraint.
Also like any reactor relying on fertile material, the thorium fuel cycle relies on a highly enriched 'firestarter' to provide the initial fast neutrons.
So yes, the thorium fuel cycle requires use of highly-enriched uranium. China has not resolved this constraint.
13/16
And some have argued that the Th fuel cycle in an MSR specifically STILL has proliferation risk.
It may be possible to operate the reactor in a specific way to extract U-233 that is not overly contaminated with U-232 (thus usable in weapons)...
fissilematerials.org/library/sgs09k…
And some have argued that the Th fuel cycle in an MSR specifically STILL has proliferation risk.
It may be possible to operate the reactor in a specific way to extract U-233 that is not overly contaminated with U-232 (thus usable in weapons)...
fissilematerials.org/library/sgs09k…
14/16
But starting up this experimental reactor is still an amazing feat. I will be watching its operation with great interest, as a commercially-replicable 100MW upgrade is expected to be built by 2030.
The liquid sodium reactors at Xiapu should be finished by this time too.
But starting up this experimental reactor is still an amazing feat. I will be watching its operation with great interest, as a commercially-replicable 100MW upgrade is expected to be built by 2030.
The liquid sodium reactors at Xiapu should be finished by this time too.
15/16
Does this mean China's done with Uranium? Definitely not, at least not in the short-term.
But I do think the Chinese nuclear newbuild between 2030-2060 will swing toward the nextgen reactors, less beholden to the import of scare U-235.
Pay attention, very long U bulls.
Does this mean China's done with Uranium? Definitely not, at least not in the short-term.
But I do think the Chinese nuclear newbuild between 2030-2060 will swing toward the nextgen reactors, less beholden to the import of scare U-235.
Pay attention, very long U bulls.
16/16
After all, Chinese nuclear capacity has to grow by 5x (at least) if the 2060 carbon neutrality goal is to be realized.
I simply don't see how that will be done with conventional U-235 fission tech. It will be thorium, or natural uranium, in one of these 4th gen reactors.
After all, Chinese nuclear capacity has to grow by 5x (at least) if the 2060 carbon neutrality goal is to be realized.
I simply don't see how that will be done with conventional U-235 fission tech. It will be thorium, or natural uranium, in one of these 4th gen reactors.
CC: nuclear tweeps
@nuclearkatie @energybants @CherylRofer @jrmygrdn @6point626 @quakes99 @NuclearTitans @JekyllCapital @ANS_org @W_Nuclear_News @JTroullioud @BillFreebairn
@nuclearkatie @energybants @CherylRofer @jrmygrdn @6point626 @quakes99 @NuclearTitans @JekyllCapital @ANS_org @W_Nuclear_News @JTroullioud @BillFreebairn
*scarce.
Dammit, there's always at least one typo.
Dammit, there's always at least one typo.
This statement has errors, please see:
https://twitter.com/pretentiouswhat/status/1419586164210561034?s=20
This statement has errors. Please see:
https://twitter.com/pretentiouswhat/status/1419586164210561034?s=20
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