Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Application submitted for US molten salt research reactor

world-nuclear-news.org

Post reply on HN
Print view View original

91–100 of 217 posts

Re: Application submitted for US molten salt research reactor

#91

Post by theluketaylor »

kenned3 wrote: post #81
ars wrote: post #41

Earlier quoted context omitted.

> 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…

Your view really depends on the design. CANDU (Canadian reactor design) is moderated via deuterium in which case there is a LOT of it circulating in the reactor core. The heavy water is syphoned off to a tritium separation unit for recovery. With a market value of $30,000 a gram, there is a clear incentive to recover it ;)

Some buddies who work on CANDU tell me they have tritium contamination everywhere as a result of this. From what they tell me it's not really a big safety issue, mostly more annoying than anything.

Re: Application submitted for US molten salt research reactor

#92

Post by samstave »

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…

https://i.imgur.com/qX2d2qg.jpg

https://i.imgur.com/InQHoSI.png

https://i.imgur.com/go5v5QL.jpg

Re: Application submitted for US molten salt research reactor

#93

Post by lolc »

elihu wrote: post #87
politician wrote: post #27

Earlier quoted context omitted.

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…

It seems like that might suggest a potential option in the search for appropriate materials to build the containment vessel and piping to hold in the salt: just make the whole thing out of salt. Anything that needs to be solid can have built-in channels with coolant piped through. The rest can maintain a sort of steady state. I'm sure there's all sorts of practical reasons why that wouldn't work, but it's an interest…

Nice hack! That sounds so easy that I wonder what the catch is.

Maybe it would need more energy for cooling than what it generates? So it would have to be scaled up to a size where the surface-to-content ratio becomes favourable. There might not be enough salt for that :-)

Re: Application submitted for US molten salt research reactor

#94

Post by HPsquared »

Turbots wrote: post #79
kenned3 wrote: post #78

Earlier quoted context omitted.

non-metals have their own problems and glass tends to have some really weird properties. I would think a major one would be their failure mode. Metals flex and expand before they eventually fail. Glass/ceramic is fine until suddenly it isn't and has a total failure. Think of a window being hit. If it were metal it would probably deform but if it is glass it shatters. Next would be joining them on-site. If needed, met…

what about glass pipes encased in said metals :-)

Glass-lined vessels and pipes are already used in the chemical industry so it's a somewhat proven technology.

Not sure if it's suited to the chemistry and temperatures (and radiation) of a molten salt reactor, but it seems like an interesting technology.

Re: Application submitted for US molten salt research reactor

#95

Post by wpietri »

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.

For sure. In theory, I'm in favor of nuclear power; especially as we try get to zero/negative net carbon emissions, nuclear plants have real advantages. But when I think about American business culture, I have a hard time imagining the company I'd trust with something that requires an extremely long-term focus (plants run for decades) and deep social responsibility.

Re: Application submitted for US molten salt research reactor

#96

Post by Galaxeblaffer »

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.

Energy too cheap to meter doesn't sound like a good investment from a capitalistic viewpoint.

Re: Application submitted for US molten salt research reactor

#97

Post by xorbax »

el_nahual wrote: post #73
throwaway894345 wrote: post #43

Earlier quoted context omitted.

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.

Part of it is molten (above the plug), part of it is frozen (the plug). Think pipes in a house in winter, where one little part of the pipe gets frozen while the rest of the pipes have liquid water in them.

And in Spring, when the broken pipe plugged with solid molten ice thaws, your house's molten ice circuit performs an emergency evacuation into the yard, saving you from the convenience of adequate molten ice pressure

Re: Application submitted for US molten salt research reactor

#98

Post by elihu »

lolc wrote: post #93
elihu wrote: post #87

Earlier quoted context omitted.

It seems like that might suggest a potential option in the search for appropriate materials to build the containment vessel and piping to hold in the salt: just make the whole thing out of salt. Anything that needs to be solid can have built-in channels with coolant piped through. The rest can maintain a sort of steady state. I'm sure there's all sorts of practical reasons why that wouldn't work, but it's an interest…

Nice hack! That sounds so easy that I wonder what the catch is. Maybe it would need more energy for cooling than what it generates? So it would have to be scaled up to a size where the surface-to-content ratio becomes favourable. There might not be enough salt for that :-)

I suppose one problem might be selecting an appropriate coolant that doesn't dissolve the salt on contact. Presumably water would, but google says that salt doesn't dissolve in oil so maybe that's an option.

Ideally you wouldn't need to expend energy to keep the coolant cold enough; rather, you'd use the coolant to boil water to run your steam generator.

Re: Application submitted for US molten salt research reactor

#99

Post by marcosdumay »

runarberg wrote: post #85
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…

> But I was under the impression that the main stumbling block for molten salt reactors was that high-energy corrosion resistant materials for containing / moving molten salt simply don't exist (yet). Is this also an issue for molten salt / liquid metal batteries[1][2] that have been proposed as a grid scale energy storage solution for renewables? The way I understand it, molten salt is used as the membrane separatin…

Molten salt / liquid metal batteries normally use alkaline salts, so steel holds it pretty well.

Re: Application submitted for US molten salt research reactor

#100

Post by phonon »

powerhour wrote: post #57
2OEH8eoCRo0 wrote: post #48

Earlier quoted context omitted.

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.

Westinghouse went bankrupt a few years ago[0]...and GE hasn't been doing well and is splitting up[1]...

[0] https://www.nytimes.com/2017/03/29/business/westinghouse-tos...

[1] https://www.usnews.com/news/business/articles/2022-07-18/ge-...

Post reply on HN