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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

#181

Post by pfdietz »

panick21_ wrote: post #175
pfdietz wrote: post #163

Earlier quoted context omitted.

Right! They've got the same thing going that ordinary LWRs do: the neutrons lose their energy in a surround liquid rather than in a solid moderator or solid structural materials other than the fuel rods (which are designed to be replaced often anyway). The design even adds some hafnium to the coolant salt (substituting for zirconium, which is the sacrificial metal you refer to there); hafnium serves to shield the rea…

> One additional advantage The problem with that is that you would likely require a different design and go threw full licensing. So in practice this will likely not be used.

Presumably it would happen at design time and a large, high thermal inertia design would be the one licensed.

Re: Application submitted for US molten salt research reactor

#183

Post by pfdietz »

panick21_ wrote: post #178
pfdietz wrote: post #164

Earlier quoted context omitted.

It means the offgas storage system has to be designed for a large heat load, even in accident scenarios. It also means the common MSR talking point that the FPs stay in the salt is not correct.

Moltex Energy talks a lot about that. It is actually pretty nice, some things stay in the salt, some leave it. The most dangerous stuff that shows up in the news a big scary cloud coming over from Japan to the US would still be in the salt. Some other things that you really don't in your fuel, like Xenon and Krypton will bubble out. So I think overall it is an advantage.

Moltex's design keeps the relevant isotopes of Xe/Kr in the fuel tubes long enough for them to (mostly) decay, so the Cs and Sr produced from the decay (mostly) stays in the fuel salt.

Re: Application submitted for US molten salt research reactor

#184

Post by cupofpython »

ethbr0 wrote: post #170
panick21_ wrote: post #152

Earlier quoted context omitted.

My understanding is that you are not allowed to build a research reactor that is bigger then a university reactor but isn't a full scale energy producing reactor. My understanding is that for such a reactor you would need the full operating license just as a grid connected PWR. And since in the US its essentially impossible to get a license for anything but a PWR, that isn't rally possible. Technology independent reg…

> Technology independent regulatory framework is one of the main reasons Canada has so many reactor startup Canada's vast tracts of land wouldn't hurt either. If a meltdown or containment breach happens, and no population centers are within 400km, that's a much better bad scenario.

yeah im not exactly mad about it being hard / impossible for people to set up a lab-based experimental nuclear reactor near me due to regulations

Re: Application submitted for US molten salt research reactor

#185

Post by mulmen »

kennend3 wrote: post #180
mulmen wrote: post #104

Earlier quoted context omitted.

Glass is already basically welded, or maybe it's more like brazing. But an oxyacetylene torch can be used to work with glass just as well as to cut or weld metal. Metals also have weird properties. Like tempering and hardening based on temperature. In an industrial setting you need expert welders with deep knowledge of the materials or a weld is going to fail and ruin your day. So it doesn't seem like a huge leap to…

I noticed you focused almost exclusively on the welding while ignoring the brittle nature of glass? I would think that putting liquid salt in a a glass pipe is somewhat asking for trouble. One of the many issues with glass is "thermal shock". Let's say there is a fire and water based sprinklers are activated.. what will the 1,400F glass do once water touches it? Or there is an accident and someone bangs into the glas…

“Glass” is a generic term for a wide variety of materials. So is “metal”. Metal can be brittle, sometimes that’s even desirable. That’s what tempering and hardening are about.

A molten salt reactor is a material science problem. Conventional “metal” doesn’t work because of the corrosion. If glass has some desirable property then we can overcome the “bumping in to it” problem. Maybe with a hand rail. Or staying away from the operational nuclear reactor.

I’m not suggesting glass actually be used. I’m saying if it was I wouldn’t be surprised.

Re: Application submitted for US molten salt research reactor

#186

Post by throwaway894345 »

robertlagrant wrote: post #174
throwaway894345 wrote: post #72

Earlier quoted context omitted.

> We can produce heat for hydrogen, replacing the need for fossil fuels in heating, transport and industry. What does it mean to produce "heat for hydrogen"? Why is heating hydrogen a useful property (how does hot hydrogen replace fossil fuels in heating, transport, and industry?)? That seems oddly specific, so I assume I'm misreading something?

I think it means we can produce heat that can power the generation of hydrogen, e.g. from water.

Yeah, I didn't realize thermalchemical water splitting was a thing.

Re: Application submitted for US molten salt research reactor

#187

Post by panick21_ »

japanuspus wrote: post #156
mjul wrote: post #46

Earlier quoted context omitted.

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 Technologie…

Thanks for posting, this sounds super cool. Now I just really wished I had a reason to order a molten salt loop.

I would love to rip the gas heating out of the house and have little nuclear reactor there.

Re: Application submitted for US molten salt research reactor

#188

Post by ortusdux »

carlmr wrote: post #165
ortusdux wrote: post #138

Earlier quoted context omitted.

It's used 2 ways in metallurgy. Mainly it is a term for test pieces cut from a batch of metal and used for proof testing. Tensile, elongation, fatigue, weldability, and many other tests require destructive testing coupons. When you take welding certification tests, you weld two coupons together, and then submit your coupon for testing. It is also a term for strips of metal that you mount in a corrosive environment as…

>test pieces cut from a batch of metal >strips of metal I mean in essence you just have to look at the word. Coupon is from French couper, which means to cut. So it's a cut-out. It has the same meaning when you look at extreme couponing and metal testing.

Yeah, I didn't think of it as an overly obscure usage, but neither Merriam-Webster or Wikipedia list the definition. Dictionary.com does. Maybe its time to edit Wikipedia over lunch =)

Re: Application submitted for US molten salt research reactor

#189

Post by AtlasBarfed »

panick21_ wrote: post #153
AtlasBarfed wrote: post #128

Earlier quoted context omitted.

Well, one thing about liquid fuel vs solid fuel is that you can move the fuel to a new reactor and, uh... ?"recycle"? / ?"overhaul"? the old one. So you could use one for 7 years why the other is retrofitted. You'd need two reactors... or... you'd need 8 and seven are online while 1 is replaced per year. So unless materials is solved, you need scalability and replacement. At least the OTHER problem with solid fuel, l…

There are a lot of options, I'm no nuclear engineer but looking at all the different companies, they all have different approaches: Terrestrial Energy: The whole reactor, including heat exchanges and so on is defined for 7 years of life. After that a second reactor is running. After a few years the original reactor is put into a storage silo and then a new reactor is placed their ready to be switch to. From memory th…

I've been thinking about the dumb idea of using solid uranium/thorium as the (closest) salt containment layer: you have a solid uranium (melting point 2000C) or thorium layer (3000C) around the salt, which may not degrade it that quickly if the salts (which are a solution basically, if it's a liquid?) are more or less saturated. Or even if it isn't, how long would a layer of uranium or thorium last? I guess that's the big question.

You don't care if the thorium or uranium captures neutrons I would think. Thorium neutron capture is a good thing.

So depending on how long the solid "breeder" inner shell hold up, when you "recondition" the inner shell, I assume you can just dissolve it into salt, feed it into the normal fission products processing that the salt fuel use, and put in a new solid uranium/thorium salt shell.

Or maybe thorium could be alloyed for more endurance properties as the containment. Of course I have no idea about the various cracking / strength / fatigue properties of thorium as a metal.

I wonder if pellets/spheres could use thorium as a surrounding material.

So how nuts is all of that?

Maybe you could do a weekly monthly re-coat of the inner layer with more thorium or uranium to replace that which gets dissolved/degraded.

Edit: ORNL on thorium properties in a nuclear environment

https://www.osti.gov/servlets/purl/4622065

Re: Application submitted for US molten salt research reactor

#190

Post by mulmen »

mnw21cam wrote: post #166
mulmen wrote: post #105

Earlier quoted context omitted.

I must not be parsing this correctly. Taking fuel away from the moderator sounds like a safety disadvantage. Maybe I don't know what a moderator does.

A moderator is a material that slows neutrons down. Slow neutrons are more likely to initiate fission in a Uranium (or other fissile) nucleus that they hit, so a moderator increases the reactivity of the reactor.

Thanks, that’s exactly the detail I was misunderstanding.
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