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Application submitted for US molten salt research reactor

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Re: Application submitted for US molten salt research reactor

#51

Post by pnw »

dangerlibrary wrote: post #12

So, in a conventional reactor, you use nuclear fission to heat/pressurize water and then use your hot, slightly radioactive steam turn a turbine. This mostly works because moving even very hot, very high pressure water around is kind of a solved problem in industry. In a molten salt reactor, you use nuclear fission to melt various corrosive salts into a fluid, and this is good because molten salts store a lot more en…

I hope we manage to improve the design over the 1960s version MSRE which cost $130m to clean up due to unforeseen problems including a near-criticality incident. Certainly there is a lot of research to be done.

Re: Application submitted for US molten salt research reactor

#52

Post by jussion_zoonist »

mrunkel wrote: post #45
AtlasBarfed wrote: post #5

I thought these were outlawed, per a LFTR video I saw once. To emphasize, I'm asking if that is the case, or was the LFTR video was engaging in misinformation, or if something changed in regulations.

LFTR?

Liquid Fluoride Thorium Reactor but I believe this reactor is using uranium[1].

[1] https://www.nrc.gov/docs/ML2024/ML20241A071.pdf

Re: Application submitted for US molten salt research reactor

#53

Post by ortusdux »

dangerlibrary wrote: post #12

So, in a conventional reactor, you use nuclear fission to heat/pressurize water and then use your hot, slightly radioactive steam turn a turbine. This mostly works because moving even very hot, very high pressure water around is kind of a solved problem in industry. In a molten salt reactor, you use nuclear fission to melt various corrosive salts into a fluid, and this is good because molten salts store a lot more en…

You are correct about the corrosion issue. I've done some work developing molten salt resistant claddings. The main culprit is chromium leaching, which de-alloys most of the metals approved for reactor design. The leeching happens at the grain boundaries, so you will hear 'intergranular attack' as a research focus.

A close second problem is the radiation itself. Elements in both the containment vessel and salt transmute. One study I read estimated that pure tungsten (a viable salt resistant material) would transmute to rhenium at a rate of 1% a year. The radiation also causes void-swelling in both the metals and pure graphite.

The standard way to test material's resistance to molten salt is to put a coupon in a crucible full of salt for a few hundred hours. A paper from 2015 showed that the material the testing crucible is made of greatly effects the rate of chromium leeching. They found that both graphite and nickel act as chromium sinks. Many designs call for graphite or nickel parts to be used alongside chromium containing steels. This reactor appears to be stainless steel with graphite moderators.

Another paper strongly suggested that radiation induced void-swelling can squeeze together the grain boundaries, greatly slowing down intergranular attack. Very little corrosion testing has been done under exposure to radiation as it is logistically difficult.

Basically, the next best step is test reactors. You can only get so far testing things in isolation.

Re: Application submitted for US molten salt research reactor

#54

Post by acidburnNSA »

Manuel_D wrote: post #50
dangerlibrary wrote: post #12

So, in a conventional reactor, you use nuclear fission to heat/pressurize water and then use your hot, slightly radioactive steam turn a turbine. This mostly works because moving even very hot, very high pressure water around is kind of a solved problem in industry. In a molten salt reactor, you use nuclear fission to melt various corrosive salts into a fluid, and this is good because molten salts store a lot more en…

> So, in a conventional reactor, you use nuclear fission to heat/pressurize water and then use your hot, slightly radioactive steam turn a turbine. Only in the more primitive reactor designs (BWR, Boiling Water Reactor). Most are of the PWR, Pressurized Water Reactor, design. In these, the water in the reactor is still liquid due to being held at pressure. This pressurized water is run through a steam generator [1] t…

> Only in the more primitive reactor designs (BWR, Boiling Water Reactor).

TRIGGERED :).

The BWR was developed after the PWR specifically to be more economical for terrestrial large-scale power generation. The PWR was designed to be compact and to work on a submarine. So the BWR is the more advanced design for power plants, arguably.

https://whatisnuclear.com/reactor_history.html#the-developme...

Re: Application submitted for US molten salt research reactor

#55

Post by PaulHoule »

pnw wrote: post #51
dangerlibrary wrote: post #12

So, in a conventional reactor, you use nuclear fission to heat/pressurize water and then use your hot, slightly radioactive steam turn a turbine. This mostly works because moving even very hot, very high pressure water around is kind of a solved problem in industry. In a molten salt reactor, you use nuclear fission to melt various corrosive salts into a fluid, and this is good because molten salts store a lot more en…

I hope we manage to improve the design over the 1960s version MSRE which cost $130m to clean up due to unforeseen problems including a near-criticality incident. Certainly there is a lot of research to be done.

The cause of the criticality accident was that they did not remove the uranium when they were done with it. This is straightforward to do, you pump F2 gas into the salt and this gas is produced

https://en.wikipedia.org/wiki/Uranium_hexafluoride

which can be stored in tanks. Instead of removing it they let the salt sit, and radioactive decay led to F2 gas being produced by the salt, which caused UF6 to be produced slowly and then migrate.

This mistake won't happen again.

Re: Application submitted for US molten salt research reactor

#56

Post by acidburnNSA »

p1mrx wrote: post #38
dangerlibrary wrote: post #12

So, in a conventional reactor, you use nuclear fission to heat/pressurize water and then use your hot, slightly radioactive steam turn a turbine. This mostly works because moving even very hot, very high pressure water around is kind of a solved problem in industry. In a molten salt reactor, you use nuclear fission to melt various corrosive salts into a fluid, and this is good because molten salts store a lot more en…

> corrosion resistant materials for containing / moving molten salt I'm interested to see what Moltex can do to simplify matters: https://www.youtube.com/watch?v=7qJpVClxzVM&t=758s Instead of pumping the salt around, they plan to leave it sitting in stainless steel tubes, and use simple convection to extract the heat. Oak Ridge rejected this idea in the 1950s because they were trying to power an aircraft, but convect…

LANL built a reactor like that, with liquid fuel in tungsten capsules. It was called LAMPRE.

https://www.osti.gov/biblio/4368180-operation-plutonium-fuel...

Re: Application submitted for US molten salt research reactor

#57

Post by powerhour »

2OEH8eoCRo0 wrote: post #48
powerhour wrote: post #44

Earlier quoted context omitted.

It's also sad that industry completely failed to convince the population that they can provide a safe solution. For all the credit we give BigCo for creating propaganda, it's curious that they were unable to be successful here, given the stakes.

They are up against big fossil fuel tycoons like the Kochs. If we are strictly talking corporate propaganda, the fossil fuel industry has plenty of that.

It seems to me that companies like GE and Westinghouse have tons of money. Add that to the billions pro-nuclear folks have in SV and you've got quite the war chest to fund effective pro-nuke campaigns.

Re: Application submitted for US molten salt research reactor

#58

Post by acidburnNSA »

martin1975 wrote: post #30

So did the Chinese beat us to this one? :)

Yes they're turning on their graphite moderated MSR reactor that's fully constructed in the next few days? weeks? not entirely sure, but soon.

https://www.world-nuclear-news.org/Articles/Chinese-molten-s...

Re: Application submitted for US molten salt research reactor

#59

Post by acidburnNSA »

mrunkel wrote: post #45
AtlasBarfed wrote: post #5

I thought these were outlawed, per a LFTR video I saw once. To emphasize, I'm asking if that is the case, or was the LFTR video was engaging in misinformation, or if something changed in regulations.

LFTR?

LFTR is just a trade name from a guy named Kirk who tried to rebrand the Thorium fueled Molten Salt Reactor.

So basically yes but like all thorium reactors it has to start with enriched uranium first.

Re: Application submitted for US molten salt research reactor

#60

Post by PaulHoule »

2OEH8eoCRo0 wrote: post #48
powerhour wrote: post #44

Earlier quoted context omitted.

It's also sad that industry completely failed to convince the population that they can provide a safe solution. For all the credit we give BigCo for creating propaganda, it's curious that they were unable to be successful here, given the stakes.

They are up against big fossil fuel tycoons like the Kochs. If we are strictly talking corporate propaganda, the fossil fuel industry has plenty of that.

As much as people portrayed an epic battle between renewables and nuclear the real winner from the move away from nuclear was natural gas fired gas turbines.

The most obnoxious thing about the energy literature is that it frequently reads like a stopped clock. People still compare the cost of nuclear energy to the cost of coal, but it's no accident that the US stopped building coal plants at the same time it stopped building nuclear plants because it stopped both for the same reason... The capital cost of a gas turbine generator (even in a hybrid cycle including a steam turbine) is dramatically smaller than the steam turbines used in coal and nuclear plants.

Since molten salt reactors run a lot hotter than LWRs they could drive

https://en.wikipedia.org/wiki/Closed-cycle_gas_turbine

but it's a technology that is not very well developed. If nuclear energy is going to compete with natural gas, however, they need to ditch the steam turbine.

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