Bearing your caveats in mind, I didn't realise anyone had built a large scale reactor. In my opinion, the more interesting talk (not only because he's a better speaker: Kirk Sorensen is a somewhat dry and unengaging speaker and his talk is a little hesitant. I recommend reading the transcript) was by Taylor Wilson, who built a small Thorium reactor in his dad's garage at age 14(!). His idea, to use these small self-contained reactors to power individual households for 30 years+ struck me as a very exciting and interesting proposition: https://www.ted.com/talks/taylor_wilson_my_radical_plan_for_small_nuclear_fission_reactors
Anyway, thanks again for your article. I hope the links are of swine interest, if you're not aware of the talks already. They're not all that long, 9'49" & 12'39" respectively. There is also a much shorter talk by Taylor Wilson (‘Yup, I built a nuclear fusion reactor’ just 3'15").
It's also why we will have the least visibility into the actual progress of the various MSR projects. Until they have run for a proving period their progress in this aspect will be opaque.
Well, one critical issue is the salt composition. As a low melting point is preferred and low Neutron absorption is required. The Oak Ridge reactor uses salt with Lithium. Which is a bad choice, as this results in high Tritium generation. And the radioactive Tritium is a problem, as the containment is quite difficult, due to diffusion of this hydrogen atom. The use of floride can result in the generation of volatile UF6 (in combination of radiation). Furthermore, the Neutron radiation should not result in radiative isotopes with long half life time. The dual fluid reactor uses Chloride salts. But I have not checked the details. So I think for a good molden salt reactor set-up a lot of research is still required. Nevertheless, Thorium is a promising nuclear fuel. Maybe in the meantime the use of fuel rods with some Thorium (e.g. U and Th mixture, or Th and Pu) in light water reactor would be a good choice (well the details of the neutron dynamics must be taken into account, especially the ratio between prompt and delayed Neutrons). Such fuel rods were tested in the past in the Shipping port reactor and also in Germany in Lingen.
Thank you for the clarification. Dry cooling is never used on commercial power plants, as the plants are normally located where cooling water is available. Have you any figures for the loss in efficiency for a dry cooling system?
A small experimental molten salt reactor can run without water, as long as the heat developed is just wasted. A larger model for electricity production will need water to run steam turbines - how else could electricity be produced? And steam turbines lose some of the circulating water in the condensation process - hence the steam rising from cooling towers.
Thorium 232 is not fissile. However, under neutron bombardment it very readily becomes U-233. This isotope of uranium is a very good fissile fuel. Reprocessing irradiated thorium fuel is required to separate out the U-233.
It should be noted that U-233 can be readily used in CANDU reactors or any of India's PHWRs. The world already has in-service nuclear power reactors that can use thorium-based fuels. For India, this was necessary because the country has relatively little uranium but large reserves of thorium.
I was one of those respondents who enquired about Thorium, so thank you for your informative article. My limited knowledge of this subject stems mostly from two TED talks. The first was by Kirk Sorensen, a NASA physicist discussing power generation of future moon bases: https://www.ted.com/talks/kirk_sorensen_thorium_an_alternative_nuclear_fuel?utm_campaign=tedspread&utm_medium=referral&utm_source=tedcomshare
Bearing your caveats in mind, I didn't realise anyone had built a large scale reactor. In my opinion, the more interesting talk (not only because he's a better speaker: Kirk Sorensen is a somewhat dry and unengaging speaker and his talk is a little hesitant. I recommend reading the transcript) was by Taylor Wilson, who built a small Thorium reactor in his dad's garage at age 14(!). His idea, to use these small self-contained reactors to power individual households for 30 years+ struck me as a very exciting and interesting proposition: https://www.ted.com/talks/taylor_wilson_my_radical_plan_for_small_nuclear_fission_reactors
Anyway, thanks again for your article. I hope the links are of swine interest, if you're not aware of the talks already. They're not all that long, 9'49" & 12'39" respectively. There is also a much shorter talk by Taylor Wilson (‘Yup, I built a nuclear fusion reactor’ just 3'15").
I think the biggest problem with molten salt reactors is corrosion. Probably solvable, but nontrivial.
It's also why we will have the least visibility into the actual progress of the various MSR projects. Until they have run for a proving period their progress in this aspect will be opaque.
Well, one critical issue is the salt composition. As a low melting point is preferred and low Neutron absorption is required. The Oak Ridge reactor uses salt with Lithium. Which is a bad choice, as this results in high Tritium generation. And the radioactive Tritium is a problem, as the containment is quite difficult, due to diffusion of this hydrogen atom. The use of floride can result in the generation of volatile UF6 (in combination of radiation). Furthermore, the Neutron radiation should not result in radiative isotopes with long half life time. The dual fluid reactor uses Chloride salts. But I have not checked the details. So I think for a good molden salt reactor set-up a lot of research is still required. Nevertheless, Thorium is a promising nuclear fuel. Maybe in the meantime the use of fuel rods with some Thorium (e.g. U and Th mixture, or Th and Pu) in light water reactor would be a good choice (well the details of the neutron dynamics must be taken into account, especially the ratio between prompt and delayed Neutrons). Such fuel rods were tested in the past in the Shipping port reactor and also in Germany in Lingen.
I was introduced to Thorium while reading Heinlein a long time ago.
Thank you for the clarification. Dry cooling is never used on commercial power plants, as the plants are normally located where cooling water is available. Have you any figures for the loss in efficiency for a dry cooling system?
A small experimental molten salt reactor can run without water, as long as the heat developed is just wasted. A larger model for electricity production will need water to run steam turbines - how else could electricity be produced? And steam turbines lose some of the circulating water in the condensation process - hence the steam rising from cooling towers.
The water used in the steam cycle is not emited, its condensed and recycled back to the steam generators.
You only get the water vapour emited if you are using evaporative cooling towers, but then its from the cooling water, not the working fluid water.
You can use dry cooling for any nuclear plant, it just costs a bit more / reduces thermal efficiency a bit.
Or with a MSR we could do a super-critical CO2 cycle (no steam), but you still can use evaporative cooling towers with that...
Some vendors are showing promise like thorizon https://thorizon.com/technology and Copenhagen Atomics https://copenhagenatomics.hubspotpagebuilder.com/jams-opinion-jan-25. I'm not entirely sure what you mean by "reprocessing" thorium.
Thorium 232 is not fissile. However, under neutron bombardment it very readily becomes U-233. This isotope of uranium is a very good fissile fuel. Reprocessing irradiated thorium fuel is required to separate out the U-233.
It should be noted that U-233 can be readily used in CANDU reactors or any of India's PHWRs. The world already has in-service nuclear power reactors that can use thorium-based fuels. For India, this was necessary because the country has relatively little uranium but large reserves of thorium.
Also, U-233 turns out to be a lousy isotope for manufacturing nuclear weapons. (One of the reasons the original MSR research at ORNL was cancelled.)