I wonder if its possible to avoid the dangers of nuclear reactors exploding etc. by simply running them *at meltdown* intentionally and simply designing around reducing the quantity of fuel to such a low quantity that containment breaches would be irrelevant

like, ok a large quantity of uranium melting down is bad, sure, but what about a small quantity? can you let it melt down, and then just sit in a containment vessel and have the heat not be an issue? or is that impossible

because like, if a melting down reactor is putting out maybe 300 GW, then maybe cut the fuel dramatically and let it melt down to only produce 1 GW?

@beka_valentine

Gonna run this by my nuke tech bud next time we chat - he does flourosalt designs.

@beka_valentine nuclear degrowth

@becha what

I know that some of the corium at Chernobyl was lighter than water and floated when it hit the bubbler tanks, so I wonder if intentionally producing floating corium is a way to achieve something like this that isn't going to just melt through the concrete

have meltdown floating corium over a very large pool of water that would take a really long time to fully boil off, and have it connected to a water source that will constantly supply new water passively to maintain a constant water level

you'd need to get pressurized stream out for power generation tho the corium would have to be directly held inside a pressure vessel. if the vessel ruptures, its over the deep water tank

ah, apparently i just reinvented the liquid fluoride thorium reactor, more or less. lol

@ciggysmokebringer apparently this is how liquid fluoride thorium reactors work, more or less?

@narylis thats why you would make it so that the runaway situation is thermally manageable!

@beka_valentine that’s kinda what this is trying to do https://www.energy.gov/ne/articles/triso-particles-most-robust-nuclear-fuel-earth

@beka_valentine Ill have to check - I forget the whole bag until I have an acute question he answers in detail

@ciggysmokebringer no i mean this is what wikipedia says about those reactors lol

@beka_valentine Oh, well Im till going to ask and phrase it 'tiny perpetual meltdown pit instead of your prototype, why not'

@beka_valentine @deetwenty

@charlotte @beka_valentine if I remember correctly (not a nuclear engineer just a physicist) some fourth gen reactors run kinda like this where those run as hot as possible so that even without cooling (or with only a passive flow) only get a bit hotter than normal (pebble bed, and IIRC liquid thorium, though the later often also includes a safety melt plug that stops things as well)

@beka_valentine most modern reactor designs already can't melt down AFAIK. And most less modern ones in current use fortunately can't really melt down in a way nearly as dangerous as Chernobyl.

(Also, since I think I saw you talking about having watched the Chernobyl miniseries recently, I want to say that it's full of made up nonsense. I can come back later with sources and reading on that if you want.)

@lonjil i watched chernobyl after i watched a few talks about how the accident happened and after reading a lengthy explanation of what happened, and after myself writing a thread about how actually chernobyl's complete failure was orders of magnitude safer than cars are

i'm curious about a meltdown mode reactor for purely intellectual reasons not safety concerns :P

the show was just for vibes, and it was impeccable for that

@beka_valentine Just my two cents in this: yes, molten salt reactors and sodium/lead cooled fast breeders exist. They also don't actually melt the fuel as they don't reach that kind of temperatures (above 2700 ºC). They 'merely' suspend the fuel in the mixture.

What I'd like to see is a plasma reactor: heat up the fuel so hot it becomes a plasma, contain it in a magnetic bottle and do your fission that way. Inherently safe.

There are a few engineering hurdles though, heh.

@collectifission oh that's an interesting idea. i was thinking about like maybe something similar to a nuclear thermal rocket but those all tend to vent their fuel or require very high temp solid containment, so i figured it was probably not feasible with uranium but plasmified uranium seems like an interesting route

@beka_valentine

- Nuclear reactors in general do not explode. These dangers are already being successfully avoided.
- Yes, there are a lot of fuel designs and reactor designs reducing the risks even further, e. g. achieving »passive safety« (no external power or intervention needed to prevent accidents). With fuel design, there are continuous improvements being done, as well as more ambitious redesigns.

@Ardubal i wasn't really interested in passive safety. i mean, if i want passive safety i'll just look to candu. i was more curious about the possibility of running a reactor where the power generation happens in the hottest possible due state so that """failure""" modes are actually just normal operating conditions

@rileywd there were definitely some concerns there yeah