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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

#41

Post by ars »

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…

> slightly radioactive steam

For anyone worried about this, the longest lived unstable isotope of oxygen (that is heavier than stable oxygen) has a half life of 26 seconds. Hydrogen can become deuterium which is stable, and finally tritium which is not.

Tritium has a long half life of 12 years, but is low energy and very easily shielded (just don't eat it).

There is very very little tritium - first you'd have to make deuterium (there isn't much), and then a deuterium would have to become a tritium, i.e. a rare event on top of a rare event.

Re: Application submitted for US molten salt research reactor

#42

Post by ortusdux »

politician wrote: post #27
ortusdux wrote: post #18

Earlier quoted context omitted.

Annoyingly, "molten salt reactor" is used to describe two different technologies. What you describe is a traditional reactor that uses molten salt to move heat. This typically leads to higher efficiencies, but does have corrosion issues. Other power generation systems can also benefit from molten salt loops - namely solar energy collectors. In the research field, "molten salt reactors" (MSRs) usually means the other…

One of those safety improvements -- a freeze plug -- passively halts the reaction in the event of a power cut. The reactor sits on top of a vault that has a larger volume separated by a narrow tube containing molten salt that has been frozen into a plug by cryocoolers powered by the turbines themselves. If the pumps stop for any reason, then the plug quickly melts and the molten fluid from the reactor drains into the…

One of my favorite safety elements is often over-looked: they operate at 1 atmosphere. So much of the cost and bulk of a traditional reactor is the shielding needed to protect from an over-pressure event.

Re: Application submitted for US molten salt research reactor

#43

Post by throwaway894345 »

phire wrote: post #33
throwaway894345 wrote: post #29

Earlier quoted context omitted.

Freeze plugs sound super cool, but this part breaks my brain: > containing molten salt that has been frozen into a plug Presumably salt can't be both molten and frozen at once, or is there something about this domain that I don't understand?

I believe they use active cooling to keep the plug frozen. If the power fails, the cooling fails and the plug melts.

Yeah, I got that (and it seems like a really elegant solution! very cool, pun intended, etc). My question was about how salt (or any other matter, really) can simultaneously be molten and frozen.

Re: Application submitted for US molten salt research reactor

#44

Post by powerhour »

EricE wrote: post #28

Way, way overdue! China has taken all of our research from the 50's and has been charging ahead. Very sad that politics and ignorance has severely kneecapped our nuclear industry :(

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.

Re: Application submitted for US molten salt research reactor

#46

Post by mjul »

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…

Molten salt loops are not as difficult with current technology as they were when they were first introduced.

There are some very interesting startups in this field working on delivering these reactors on an industrial scale rather than the "artisanal" reactors that dominate today:

Copenhagen Atomics [1] is one. They offer a molten salt loop for rapid prototyping [2] if you want to try it yourself.

Seaborg Technologies is also building a compact molten salt reactor. [3] They have a subsidiary, Hyme, to use the same molten-salt technology to provide grid-scale energy storage to balance electricity grids with variable generation from e.g. wind and solar power. [4]

[1] https://www.copenhagenatomics.com/ [2] https://www.copenhagenatomics.com/products/molten-salt-loop/ [3] https://www.seaborg.com/ [4] https://www.seaborg.com/press-release-hyme

Re: Application submitted for US molten salt research reactor

#47

Post by YakBizzarro »

ars wrote: post #41
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…

> slightly radioactive steam For anyone worried about this, the longest lived unstable isotope of oxygen (that is heavier than stable oxygen) has a half life of 26 seconds. Hydrogen can become deuterium which is stable, and finally tritium which is not. Tritium has a long half life of 12 years, but is low energy and very easily shielded (just don't eat it). There is very very little tritium - first you'd have to make…

Not compltly accurate. It's true that the half-life of tritium is short compared to long lived actinides. However, like hydrogen, it diffuses very easily and it's not easy to contain. In fact, it's one of the few things emitted in the environment during normal reactor operations. As beta emitter, you are right that it's dangerous only when ingested, but it's very easy to breath of to get it from other ambient sources

Re: Application submitted for US molten salt research reactor

#48

Post by 2OEH8eoCRo0 »

powerhour wrote: post #44
EricE wrote: post #28

Way, way overdue! China has taken all of our research from the 50's and has been charging ahead. Very sad that politics and ignorance has severely kneecapped our nuclear industry :(

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.

Re: Application submitted for US molten salt research reactor

#49

Post by ortusdux »

throwaway894345 wrote: post #43
phire wrote: post #33

Earlier quoted context omitted.

I believe they use active cooling to keep the plug frozen. If the power fails, the cooling fails and the plug melts.

Yeah, I got that (and it seems like a really elegant solution! very cool , pun intended, etc). My question was about how salt (or any other matter, really) can simultaneously be molten and frozen.

It can't. Well, maybe at its triple-point, but that is another story. It is just a quirk of the language due to it being know as molten salt. For example, my drink is full of molten water that has been frozen into cubes.

Re: Application submitted for US molten salt research reactor

#50

Post by Manuel_D »

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] that boils non-radioactive water that never comes into contact with the reactor.

1. https://en.wikipedia.org/wiki/Steam_generator_(nuclear_power...

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