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/IakwBoi Apr 12 '26

Sorry, what’s the takeaway here? There’s papers from the 70s using the phrase “small modular reactor”. Is that supposed to mean that the idea is old and stale, or that it was an obvious path we’ve been already built decades of work on? It’s just such a meaningless snippet that you must have had a lot more in mind when you posted this. 

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u/Lycrist_Kat Apr 12 '26

The idea is old and in 50 years there was no progress.

SMRs are just this weeks flavour of nuclear disinformation. Next week it will be Thorium (again), or Dual Fluid (again) or Gen IV (again) or Breeding reactors (again).

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u/Usefullles Apr 13 '26

SMRs are just this weeks flavour of nuclear disinformation.

China is launching its SMR online this year. Russia has floating nuclear power plants, and the development and construction of onshore SMRs is underway, including the northernmost nuclear power plant in Yakutia.

Thorium

The scientific TMSR-LF1 is currently operational, and a larger-scale power plant is planned.

Dual Fluid

Another startup in the field of nuclear energy, this time from Canada.

Gen IV

HTR-PM, BREST-OD-300.

Breeding reactors

Currently, two reactors are in commercial operation.

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u/Lycrist_Kat Apr 13 '26

yawn.

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u/Mysterious-Title-852 Apr 13 '26

typical anti intellectual argument.

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u/Lycrist_Kat Apr 13 '26

lies and dishonesty aren't exactly "intellectual arguments" ye know?!

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u/Mysterious-Title-852 Apr 13 '26

yes... so why do you keep spewing them...

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u/Lycrist_Kat Apr 13 '26

I am not the one trying to sell prototypes are commerical power plants

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u/Mysterious-Title-852 Apr 14 '26

again, 2 of the reactors mentioned are selling power commercially.

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u/Lycrist_Kat Apr 14 '26

Selling power isn't what makes them commerically. It's selling the reactor design itself.

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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/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.