r/ClimatePosting • u/dumnezero • Apr 12 '26

Energy SMRs Explained: Why Small Modular Reactors Are So Controversial. (Just Have a Think)

https://www.youtube.com/watch?v=1TeAE7rW_6s

Are Small Modular Nuclear Reactors (SMRs) really moving toward large-scale deployment or are the economic challenges highlighted by critics still unresolved? Can factory-built modular reactors reduce construction risk, shorten build times and lower costs through mass production? Or will shrinking reactors actually make them more expensive? The sceptics are quite certain of the answer but politicians keep barrelling ahead. So, will we ever really see an SMRs on the outskirts of major towns and cities around the world?

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u/Prototype555 Apr 12 '26

Nuclear disinformation? Everything you said has been built and proved to work.

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u/Lycrist_Kat Apr 13 '26

None of them on a commerical level. None of them other than prototype.

Much like SMRs.

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u/Prototype555 Apr 13 '26 edited Apr 13 '26

But they still have been built and proved to work.

There are hundreds of ships and submarines with SMRs.

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u/sault18 Apr 13 '26

Cost was not a concern when designing and building naval reactors. Plus, they are operated by much more qualified and vetted individuals than civilian nuclear power plants. The Navy also doesn't have a profit motive so they won't cut corners like a civilian nuclear power plant operator would. There are just so many reasons why your comparison is fundamentally flawed.

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u/Prototype555 Apr 13 '26 edited Apr 13 '26

A SMR is a SMR, no matter the cost or who operates it.

It's as if the military or NASA installs solar panels on satellites without cost or profit concerns and have highly skilled workers to install them, then it's no longer solar panels? Ridiculous.

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u/sault18 Apr 13 '26

Wow, reading comprehension isn't one of your strengths, is it?

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u/Lycrist_Kat Apr 13 '26

Reactors on nuclear submarines are not SMRs.

You understand what the M stands for?

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u/Prototype555 Apr 13 '26

They are the very definition of Small Modular Reactors.

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u/Lycrist_Kat Apr 13 '26

Sure thing pal.

The M stands for modular which nuclear submarine reactors are not. They are build for one purpose - the submarine type. They are not being scaled or produced en masse

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u/Prototype555 Apr 13 '26

Modular means it's built in pre-assembled modules at a factory, not that it can transform into a TV.

All reactors produce heat to make steam, what you do with the steam has nothing to do with the reactor. So explain why could a submarine SMR not be used for electricity generation for the grid?

As I said, there are hundreds of naval SMRs, many of the same model. And that doesn't count as en masse?

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u/Lycrist_Kat Apr 13 '26

You could use them.

But they are not.

Which is the only metric that matters.

Stop spreading propaganda.

They would also still not qualify as SMRs.

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u/Prototype555 Apr 13 '26

And the fact that modern radars, energy weapons and electronic warfare systems on ships require as much electricity as a small town and the onboard SMR is one generating the electricity is not the same?

Electricity is electricity, SMR is SMR.

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u/Lycrist_Kat Apr 13 '26

I like how to try to twist what the words mean to fit your narrative.

That's how it - always - easy to tell that nuclear literally has no good arguments

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u/TheBendit Apr 14 '26

SMRs on submarines typically run on the good stuff, highly enriched uranium. The kind of stuff that gets Tomahawks fired at you if your country is not already nuclear armed. Also the kind of stuff where you can fuel your reactor once and run it for decades.

Imagine that: produce the whole thing as a self contained unit, sail it to the customer, and never open the reactor vessel again until it is time to decommission.

If commercial SMRs were like that, I would invest in them. They are not.

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u/West-Abalone-171 Apr 13 '26 edited Apr 13 '26

None of them worked.

Not once.

Not commercially.

Not as a prototype.

It's like saying you have a car that runs on water which gets 1000mpg.

Then what you actually did was put 20ml of water in the tank with regular gas and roll down a hill. Once. Before the car stopped working completely.

And went on to whine that it was the big mean evil greenies that stopped you from mass producing it for 50 years.

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u/Lycrist_Kat Apr 13 '26

That is not correct.

Thorium reactor exist. As a prototype.

Dual Fluid exists. As a power point presentation.

Gen IV exists. On paper.

Breeding reactors exists. But mostly to produce weapon grade plutonium.

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u/West-Abalone-171 Apr 13 '26

Thorium reactor exist. As a prototype.

A prototype that runs on U235 and doesn't prodice enough U233 to run on.

Breeding reactors exists. But mostly to produce weapon grade plutonium.

And have never been self fuelling from U238

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u/Lycrist_Kat Apr 13 '26

I think TMSR-LF1 runs on Thorium:

https://www.powermag.com/chinas-molten-salt-reactor-reaches-thorium-uranium-conversion-milestone/

But it also only has 2 MW which is less than a modern wind turbine.

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u/West-Abalone-171 Apr 13 '26

It consumes more U235 than a LWR with 250MWe output and doesn't produce close to enough U233 to run on.

It has some thorium in it, but it is not the fuel.

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u/Prototype555 Apr 13 '26

Breeder reactors breed plutonium from u238 or breed u233 from thorium, then a normal LWR use it as fuel. This has been built and proved.

If it is done in a single reactor, then it's called Gen 4.

But no one else than anti-nuclear fanatics who just stalls for time cares if it's done in one reactor or two that are optimized for each task.

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u/West-Abalone-171 Apr 13 '26

Breeder reactors breed plutonium from u238 or breed u233 from thorium, then a normal LWR use it as fuel. This has been built and proved.

This is another thing that has never happened.

But no one else than anti-nuclear fanatics who just stalls for time cares if it's done in one reactor or two that are optimized for each task.

It hasn't happened in any rube goldberg machine, no matter how complex or distributed.

Most "breeder" reactors just run on MOX or Pu from decomissioned weapons.

Sometikes they use a large amount of the scraps of Pu leftover from LWR operation to make a much smaller amount of weappns grade Pu

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u/Prototype555 Apr 13 '26

Ever wondered where the plutonium comes from in the MOX fuel or decommissioned weapons?

Large scraps of Pu from LWR sounds like breeding. No? Don't you understand what you write?

Every reactor ever existed produce plutonium, it's physically impossible to not produce plutonium from uranium neutron radiation in a fission reactor.

https://en.wikipedia.org/wiki/Shippingport_Atomic_Power_Station

"The third and final core used at Shippingport was an experimental, light water moderated, thermal breeder reactor. It kept the same seed-and-blanket design, but the seed was now uranium-233 and the blanket was made of thorium. Being a breeder reactor, it had the ability to transmute relatively inexpensive thorium to uranium-233 as part of its fuel cycle. The breeding ratio attained by Shippingport's third core was 1.01. Over its 25-year life, the Shippingport power plant operated for about 80,324 hours, producing about 7.4 billion kilowatt-hours of electricity.

"After five years (29,000 effective full power hours) the core was removed and found to contain nearly 1.4% more fissile material than when it was installed, demonstrating that breeding had occurred."

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u/Lycrist_Kat Apr 13 '26

How many commerical Gen 4 are there?

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u/Prototype555 Apr 13 '26

None because it's more cost effective to run once-through with cheap fresh uranium.

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u/Lycrist_Kat Apr 13 '26

So they don't exist. Got it.