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Clive Robinson • August 14, 2025 4:08 AM
@ not important, ALL,
With regards “Small Modular Reactors”(SMRs) whilst,
“SMRs are not only smaller but quicker to build than traditional nuclear plants, with
costs likely to come down as units are rolled out.He estimates that the world will need 400 SMRs by 2050.”
Is truish the estimate for needed SMRs for just AI/Data center plans alone was given as actual more than 2500 SMRs world wide by the late 2030’s (though this has been “backed-off” more recently).
What is left out is SMRs are like the worlds most toxic batteries that can not be recycled…
Russia is a case in point they produced a number of reactors for naval vessels not just submarines but ice breakers and they worked for maybe thirty years… Less than half a century after commissioning the vessels are tied up as rotting hulks in out of the way navy yards because Russia can not dispose of them in a suitable way.
Plutonium by the way is perhaps the most poisonous element there is and last time I looked it up it was said that 20grams or about 2/3rds of an ounce was sufficient to kill an American football stadium full of people relatively quickly.
And there are a lot more “fun” radionuclides hiding away in the other metals and structural materials caused by the energy of neutrons etc just smashing into other atoms[1].
Some have half lives measured in more than 10,000years. Not the kind of stuff you want shoved in landfill or dumped in the sea (which are the two “low cost” most favoured ways to get rid of waste…).
[1] You can read about some of the fun stuff about radio uclieds at,
https://nuclear-energy.net/what-is-nuclear-energy/radioactivity/radionuclide
finagle • August 14, 2025 5:52 AM
@Clive
depends what the reactor technology is.
Plutonium is the primary product of fast breeder reactors, which were the main design developed post WWII to rapidly create weapons grade material. Subsequent generations of reactors have moved to more complete radio-isotope decay producing less plutonium etc. The expectation for SMRs is that they are going to be built as thorium reactors, which actually consume the plutonium they generate and produce significantly less waste, and of significantly lower toxicity and difficulty of disposal.
The Russian reactors you’re referring to were built with intentionally inadequate shielding and discharging waste directly into their environment. Suggesting replicating those designs is quite unlikely to win any tenders, but I’m not going to rule it out after Microsoft signed a 20 year deal to buy electricity generated from the 70s vintage Pressurised Water Reactor on 3 Mile Island. Yes, that 3 Mile Island, and using a reactor right next door to a very similar but slightly larger and more modern one that failed. Got to power co-pilot somehow right.
As for radioactivity, it’s important to understand levels and types. We live in a radioactive environment, without which we would possibly not exist. Radio isotopes abound. Cut granite leaks radon, bananas produce anti-matter from potassium decay.
My concern about new nuclear energy plants is that they’re new thorium based designs, small, and designed with state of the art cybersecurity to avoid being weaponised. Of those 3 I can see the last one being the real problem. Oh, and in the UK ideally UK owned, but that might make them the only utility that is.
iAPX • August 14, 2025 7:41 AM
I worked on a projet of automated code audit, trying different LLLM (some instructs, some code-instruct) at different sizes.
A part of this project has been naturally to evaluate code security, and strategies with different LLM to at least pre-evaluate it to enable review by a Senior coder.
I discovered that some of them are backdoored: not only you might put instructions on code comment to NOT report a backdoor in code (it was expected), you might use variable names, function names, character strings to change its behaviour!
And I say it’s backdoored for one of them in 7b and 14b, because the more you use the word “backdoor” inside it the more safe the code is considered by these LLMs.
A one-liner php that move an uploaded file (no check whatsoever) wherever it’s asked for (no check whatsoever). The dumbest code possible to be able to effectively backdoor a webapp.
Isn’t the main “cybersecurity” use case of AI to take the corporate “cybersecurity trainings”? That’s something AI is pretty good at.
Clive Robinson • August 14, 2025 2:03 PM
@ finagle,
In “theory” Thorium reactors can be designed such that they can not even start thus “have to be lit” with a source that is in effect weapons grade, or already started.
However the problem is that once started / lit, it is still possible to “make” more interesting / problematic radioisotopes.
But there is another issue…
As you note thorium reactors could be used to chow down on plutonium and similar.
Thus the suggested use of thorium reactors to consume the stock piles of current reactor waste that do contain the likes of plutonium that have a half life longer than mankind is likely to survive (unless there is a mass outbreak of “common sense”).
This idea along with a standard neoconservative / capitalist mantra of “minimise costs to increase profits” is inevitably going to open a serious security hole.
The urge to “burn the waste” at a profit will by competition have two basic effects,
1, Maximise delivery of waste per truck to minimise delivery cost.
2, Minimise security of any waste carrying truck to minimise security cost.
It’s not hard to see what will happen… That is commercial market competition will ensure the minimisation of security and maximise dangerous waste load per vehicle. Such that eventually the trucks will get attacked and material that can be used in undesirable / problematic ways will get stolen at some point…
Oh and as far as I’m aware there has not been a 4th generation of reactor design that is fail safe, inherently secure, and importantly commercially viable in the way being asked for.
Even Elon Musk has indicated there is not enough generating capacity for AI and won’t be in the foreseeable future[2] due to the fact that the use of nuclear is currently impractical. Which is one of the reasons why the “Three Mile Island Deal” by Microsoft is under negotiation.
[1] For those interested in what Russia has dumped in the sea just up from Norway,
It might shock you. But remember that is only some of Russian dumping… Then there is the French, UK and US dumping we know has happened but the where / what / and how much is still effectively “State Secrets”.
[2] Musk said the AI issues in order were “Chips, Transformers, and Generation”,
Whilst Chips is going to get embarrassing due to US political stupidity over China, Musk going on about “transformers” is shall we say a century or so late. Due to other issues –line capacitance and inductance, peak voltage, etc– electrical grid backbones are switching from problematic more than a century old AC distribution to DC distribution. Musk should know this due to his involvement with the North Australia to Singapore solar / battery subsea cable supply system.
As for Generation, data centers pulling 1GWatt continuously is about the same as a 2nd generation Nuclear reactor output. 2nd generation reactors are something that you really do not want within a thousand kilometres of you (think of the Japanese and Ukrainian reactors that have caused significant issues over such distances).
Privacy • November 17, 2025 7:52 AM
Plutonium can be held in the hand, it feels warm, but don’t ingest it.
Polonium 110 when ingested is fatal over some days, I think even in microgram amounts.
In the 1950s and 1960s small nuclear reactors were explored for household heating.
Who? • November 18, 2025 10:07 AM
@ Clive Robinson
What is left out is SMRs are like the worlds most toxic batteries that can not be recycled…
And the closest we will ever get to a perpetual motion machine!
Nuclear energy is bad for us, but worse for future generations. Just imagine a building as old as the pyramids being maintained today because it can be the next Chernobyl, Fukushima, whatever… if not.
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not important • August 13, 2025 6:21 PM
AI can make us UK’s biggest firm, Rolls-Royce says
https://www.bbc.com/news/articles/ce8772d4jzgo
=Rolls-Royce’s plan to power artificial intelligence (AI) with its nuclear reactors could make it the UK’s most valuable company, its boss has said.
The engineering firm has signed deals to provide small modular reactors (SMRs) to the UK and Czech governments.
Rolls-Royce already supplies the reactors that have powered dozens of nuclear
submarines. Mr Erginbilgic said the company has a massive advantage in the future market
of bringing that technology on land in the form of SMRs.
SMRs are not only smaller but quicker to build than traditional nuclear plants, with
costs likely to come down as units are rolled out.
He estimates that the world will need 400 SMRs by 2050. At a cost of up to $3bn each, that’s another trillion dollar-plus market he wants and expects Rolls-Royce to dominate.=