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What is a molten salt reactor?

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Re: What is a molten salt reactor?

#41

Post by ncmncm »

Manuel_D wrote: post #39
ncmncm wrote: post #36

Earlier quoted context omitted.

Not true. Storage is not built out because you need a lot more top-line renewable generating capacity, to charge it from, to make it worth building. So, the money is overwhelmingly-better spent on generating capacity, meantime. Thus, it is being spent there. Storage cost is falling even faster than solar or wind ever did. Some storage pilot projects have been abandoned as alternatives undercut them, as happened to co…

The goal of the Paris accords is to have zero emissions by 2050. Not just zero emissions from electricity, but all emissions eliminated: transportation, industry, and heating too. Just the electricity usages amounts to 500 GWh per hour for the US and 2.5 TW globally. Storing even just 4 hours of storage (a modest goal, many renewable plans call for days of storage) is outside the scope of anything we could deliver th…

You can repeat this until you are blue, and it will still not be true.

Also: the Paris accords are for net-zero. That means no more carbon emissions than carbon reclaimed and sequestered. (Carbon reclaimed and then burnt again does not count.)

Re: What is a molten salt reactor?

#42

Post by PebblesHD »

zbrozek wrote: post #37
Manuel_D wrote: post #7

Earlier quoted context omitted.

Energy per capita, yes. But electricity per capital not necessarily. Things like smelting, shipping, and air travel, all of which depends on fossil fuel must be electrified.

I'm actively trying to drive down my marginal cost of electricity explicitly so I can use more of it to make my life better. I am absolutely driving up my total energy consumption, not just switching fuels.

I’m in the process of installing solar panels and storage for exactly this reason. There are things I want to do at home, running servers, air conditioning etc. that are prohibitively expensive and unnecessarily polluting under current conditions that I’d love to be able to run without thinking about it.

Re: What is a molten salt reactor?

#43

Post by Blackthorn »

acidburnNSA wrote: post #10

See also my thorium myths page https://whatisnuclear.com/thorium-myths.html

Very nice. Could you add one about the waste cycle? Like, it feels true in one sense (maybe there's less fuel waste that matters, or so the claims go) but way false in another (molten salt is nasty as hell and requires a lot of maintenance which means a lot of irradiated waste).

Re: What is a molten salt reactor?

#44

Post by Manuel_D »

ncmncm wrote: post #41
Manuel_D wrote: post #39

Earlier quoted context omitted.

The goal of the Paris accords is to have zero emissions by 2050. Not just zero emissions from electricity, but all emissions eliminated: transportation, industry, and heating too. Just the electricity usages amounts to 500 GWh per hour for the US and 2.5 TW globally. Storing even just 4 hours of storage (a modest goal, many renewable plans call for days of storage) is outside the scope of anything we could deliver th…

You can repeat this until you are blue, and it will still not be true. Also: the Paris accords are for net -zero. That means no more carbon emissions than carbon reclaimed and sequestered. (Carbon reclaimed and then burnt again does not count.)

Sequestration is an even bigger moonshot than storage. Most of the "carbon offsets" are in the form of payment in exchange for other countries to agree not to cut down forests. It isn't actually removing carbon from the atmosphere.

Actually removing carbon dioxide from the atmosphere is the stuff of scientists and PR moves. Nobody has a serious plan to remove carbon dioxide from the atmosphere at relevant scales. The only example I can find would capture only 900 tons of CO2 per year.

We'd need to build 4 nuclear plants for each one that exists in the US to have a 100% nuclear electrical grid. It's something that we've done before, we would reach this goal early if we built plants at the same place we did in the 1960s and 1970s. This doesn't rely on a moonshot succeeding.

Renewables rely on a storage breakthrough or a sequestration breakthrough (but if we have the latter we could just keep using fossil fuels anyway). Relying on any kind of breakthrough yielding a 1,000x improvement is very reckless. You can insist until your lips turn blue that we just need to some type of electrolysis invention of another breakthrough of thermal storage and it's surely right around the corner. But until storage or sequestration is on the market, there's no real plan just hope that some breakthrough will happen.

1. https://www.climatecentral.org/news/first-commercial-co2-cap...

Re: What is a molten salt reactor?

#45

Post by ncmncm »

Manuel_D wrote: post #44
ncmncm wrote: post #41

Earlier quoted context omitted.

You can repeat this until you are blue, and it will still not be true. Also: the Paris accords are for net -zero. That means no more carbon emissions than carbon reclaimed and sequestered. (Carbon reclaimed and then burnt again does not count.)

Sequestration is an even bigger moonshot than storage. Most of the "carbon offsets" are in the form of payment in exchange for other countries to agree not to cut down forests. It isn't actually removing carbon from the atmosphere. Actually removing carbon dioxide from the atmosphere is the stuff of scientists and PR moves. Nobody has a serious plan to remove carbon dioxide from the atmosphere at relevant scales. The…

It would take until well after 2050 to build those, and they would cost many, many times as much as renewables + storage, and produce zero kWh in the meantime. Just the money spent on coal, in the meantime, not counting nuke construction, would be more than the cost of building out enough renewables.

No "breakthroughs" are needed for storage. Everything works already. All that is unknown is which will end up cheapest.

But you already knew all of this.

Re: What is a molten salt reactor?

#46

Post by ncmncm »

ortusdux wrote: post #29
m0llusk wrote: post #19

This boldly claims that molten salt reactors are safe, but my understanding is that these systems require carefully engineered coatings to function and that in practice every such system has leaked liquid sodium. The statement may be essentially true kind of like saying elevators are safe, but there is still room for risk analysis and expectation of occasional failures.

I've been working on molten salt reactor claddings for a few years now. MSRs are very safe. First, there are two main groups of molten salt systems. One group uses generic salt to transport heat. This usually provides efficiency gains over water based systems. These are the systems that might leak sodium and it's no big deal. The 2nd kind of system uses a salt with the fissile material dissolved in it. This is what t…

If you find "materials the storage vessel is made of" in the salt, do you shut it down and abandon it?

Alternative would be to drain it into a holding tank and, what, send somebody in to fix it? Who?

Re: What is a molten salt reactor?

#47

Post by irjustin »

ortusdux wrote: post #29
m0llusk wrote: post #19

This boldly claims that molten salt reactors are safe, but my understanding is that these systems require carefully engineered coatings to function and that in practice every such system has leaked liquid sodium. The statement may be essentially true kind of like saying elevators are safe, but there is still room for risk analysis and expectation of occasional failures.

I've been working on molten salt reactor claddings for a few years now. MSRs are very safe. First, there are two main groups of molten salt systems. One group uses generic salt to transport heat. This usually provides efficiency gains over water based systems. These are the systems that might leak sodium and it's no big deal. The 2nd kind of system uses a salt with the fissile material dissolved in it. This is what t…

> These are the systems that might leak sodium and it's no big deal.

Sorry can you back this statement up with more than "it's safe, trust me"?

I'm not knowledgeable enough to say if this statement can be accepted at face value. History has shown that's not enough.

But to me, any system that leaks by accident is a disaster waiting to happen on time scales that power plants are expected to operate on.

Re: What is a molten salt reactor?

#48

Post by mlyle »

ncmncm wrote: post #38
socialdemocrat wrote: post #33

Earlier quoted context omitted.

It is worth pursuing solutions like Moltex though because eventually we need to find a replacement for the gas power plants which will be backing up wind and solar. Pumped hydro, cryogenic storage, thermal storage, batteries, green hydrogen etc may tackle a lot of that but we simply don’t know what solution will end of working best. Wind and solar has to be primary focus for the next 10-15 years but once we reach 60-…

Existing peaker plants will burn synthetic ammonia or hydrogen, once there is enough spare renewable generating capacity to synthesize that. In the meantime, we build out the renewable generating capacity. Then we build out hydrogen and ammonia synthesis. There is no place for nukes in the inner solar system. Out Jupiter and beyond, ok.

> In the meantime, we build out the renewable generating capacity.

We're already dipping into times of negative electric power cost in places with high renewable penetration... and a whole lot of the rest of the day where storage is needed, and a whole lot of usages that are not electric yet which will increase demand.

Yes, more renewable build out is necessary and helpful. But it won't get us low enough in carbon intensity soon enough alone.

Re: What is a molten salt reactor?

#49

Post by mlyle »

ncmncm wrote: post #46
ortusdux wrote: post #29

Earlier quoted context omitted.

I've been working on molten salt reactor claddings for a few years now. MSRs are very safe. First, there are two main groups of molten salt systems. One group uses generic salt to transport heat. This usually provides efficiency gains over water based systems. These are the systems that might leak sodium and it's no big deal. The 2nd kind of system uses a salt with the fissile material dissolved in it. This is what t…

If you find "materials the storage vessel is made of" in the salt, do you shut it down and abandon it? Alternative would be to drain it into a holding tank and, what, send somebody in to fix it? Who?

> If you find "materials the storage vessel is made of" in the salt, do you shut it down and abandon it?

You identify the operational error in salt chemistry that has lead to losing some of the storage vessel material, and then you perform engineering analysis on the new resultant factor of safety. If necessary, next fueling cycle you shut down the reactor and perform remediation actions.

Re: What is a molten salt reactor?

#50

Post by mlyle »

abracadaniel wrote: post #25
m0llusk wrote: post #19

This boldly claims that molten salt reactors are safe, but my understanding is that these systems require carefully engineered coatings to function and that in practice every such system has leaked liquid sodium. The statement may be essentially true kind of like saying elevators are safe, but there is still room for risk analysis and expectation of occasional failures.

Storing and piping molten salt proved too unreliable for the Crescent Dunes solar collector. Swapping out the simple and free heat source with a much more complex nuclear reactor doesn’t seem like a good idea. https://en.wikipedia.org/wiki/Crescent_Dunes_Solar_Energy_Pr...

Mostly because of problems with foundations and the power-tower architecture. And note that other molten salt concentrated solar plants have done just fine, and that nuclear power is much more highly regulated and requires a higher degree of engineering analysis than a concentrated solar plant (that's why it's so expensive, in large part!)
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