Does the reactors for the UK's nuclear powered submarine fleet. So they do know stuff about 'small' reactors.

But the trouble with 'small' reactors such as the rolls-royce PWRs as I understand, is that they require high-enriched uranium, which is a proliferation issue and regulatory headache. They also burn only a tiny fraction of the available energy in the fuel, leaving it still rather highly enriched when it becomes spent, which is a decommissioning issue and another regulatory headache. The Trafalgar class nuclear subs are currently costing £117m just to [1] "prepare for defueling" of one sub..

Then comes the issue of site security, it is much easier to defend one big plant than ten small ones, although you could put ten SMRs on the same site perhaps.

That and the worlds main supplier of high-enriched fuel is, er, Russia.

Personally, I would love to see some actual innovation in Fission power, such as using an accelerator-driven Neutron source to burn the huge stockpile of Plutonium that languishes at Sellafield with a very negative price tag attached.

[2] "Accelerator-driven subcritical reactors" seem to me like the safest and most effective way to use what would otherwise be high-level nuclear waste. I'd be interested in any other opinions on that from our venerable commentariat.

[1] https://www.theengineer.co.uk/content/news/babcock-wins-114m-contract-to-defuel-trafalgar-class-subs

[2] https://en.wikipedia.org/wiki/Accelerator-driven_subcritical_reactor

But the trouble with 'small' reactors such as the rolls-royce PWRs as I understand, is that they require high-enriched uranium, which is a proliferation issue and regulatory headache.

As I understand it, this is why there's been delays rather than just using the same SMRs as we've been installing in our Astutes. So the SMR is designed to run on low, rather than high-enriched uranium. Which still leaves the usual nuclear challeng of how to feed & care for your reactors and run them off a mostly standardised fuel. Then economies of scale processing and re-processing fuel for the entire fleet, large or small. Or take a typical approciate to regulatory burdens and ignore them. Currently we're signed up to treaties limiting enrichment, but if other countries are ignoring those, why shouldn't we? After all, HEU has more energy potential than LEU, and this time, we aren't going to divert fuel to make more bombs. Honest.

I'd not appreciated just how enriched the UK sub fuel actually is. Very similar to the SL-1 reactor fuel. 90+% enriched.

It makes sense as you have a very small core. And to get good life you need a high reactivity, which was ultimately the downfall of the SL-1 reactor as it went prompt critical due to the main control rod being manually withdrawn too far.

On the larger scale, the government has announced a £14.2 billion ($19.2 billion) investment to START TO build the Sizewell C nuclear power plant, as we all know the final cost will be around 71 Billion!

Hinkley point C's costs are as the below quote.

In January 2024, EDF announced that it estimated that the final cost would be £31–35 billion (2015 prices, excluding interim interest), £41.6–47.9 billion in 2024 prices, with Unit 1 planned to become operational in 2029 to 2031

And that is with the additional costs incurred from Brexit (customs delays and tariffs on imports) and the Covid 19 lockdown (which meant that most of the workforce wasn't allowed on site but still had to be paid), design changes to fix problems identified in reactors that have been built to this design elseware and inflation.

So where has the cost of £71 billion come from? Because that's literally over double the cost of the Hinkley point C reactor in 2015 prices, and we can reasonably assume that there wouldn't be additional customs costs introduced, or another pandemic lockdown during the building process.

The inflation part of the cost is almost exclusively caused by excessive energy prices which is in turn caused by the fact that we are reliant upon gas for our energy and heating and have to import it at whatever the going cost of gas on the market is. Notably the government paid £52.2 billion over the winter of 2022-2023 to reduce the number of people who froze to death as a result of their energy policies to a tolerable number. One of these reactors outputs ~10% of the countries total energy usage.

If it'd have been built sooner then it would have reduced either the death toll, or the bill to the government. The reality that if these aren't built then the lights are going to go out at some point in the future is now starting to sink home in Whitehall, which is why they are building these.

On the larger scale, the government has announced a £14.2 billion ($19.2 billion) investment to START TO build the Sizewell C nuclear power plant, as we all know the final cost will be around 71 Billion!

It's still a lot less than we've wasted tilting at windmills. A lot will depend on whether the goverment has written a decent contract to make the Sizewell consortium liable for cost overruns though. In theory, given Hinkley's costs were inflated to bail out EDF and pretend it was a new, FOAK design, Sizewell C should be cheaper given the lessons learned etc.

To be honest, for a project this size you can't predict the costs because there are just too many unknown events that could happen. All you can do is plan for contingency funds to be in place. Even then it's a guess how much they should be and there is enormous pressure on any government to pretend they can do things cheaply.

Let's say Sizewell C is a 10 year project. Just look at the unpredictable effects in the last 10 years as a guide for the type of things that could happen. The Brexit referendum was still a year away, COVID happened out of the blue, then there was the almost-recession and inflation that made construction costs rise. And that's without factoring any change in government.

£14.2 billion would pay for the installation of about 1.5 million 3 to 4 kW solar panel + battery installations.

And? Solar capacity factor varies between zero and 5% in winter, won't meet anybody's heating demand, won't charge EVs overnight, and has no useful output across current morning and evening peak periods all year round. All it does is suck up subsidies, make distribution networks trickier to manage, and still requires thermal or other backup for the times when the sun isn't shining It's a very poor generation choice for the UK grid.

"£14.2 billion would pay for the installation of about 1.5 million 3 to 4 kW solar panel + battery installations."

But why do that instead of providing reliable energy?

"a golden age of clean energy abundance"

For my great grandchildren, you mean? And when you're no longer around to explain why you were so gormlessly wrong.

"energy so cheap they wouldn't need to meter it"... the promise when Calder Hall was first opened

"Energy too cheap to meter"

Worked well last time!

Just waiting for Reeves to talk about white hot....

Then we'll have "the pound in your pocket"

Would be fun to have "He would say that" again.

1 downvote for each of us!

The last person in the whole UK who believes anything Starmer/Reeves say is also a Register reader! What are the odds of that?

If we are to take the MMCC theory stuff seriously and want cleaner energy then nuclear was the only option left (as we pretty much knew back in the early 2000's). Of course the gov must choose every wrong option before stumbling on the right one.

I personally believe SMR's are the wrong bet. Pebble reactors are inherently safe and therefore require much less regulation, legal procedures and safety systems which could speed up the build significantly. Just because these SMR's are built in a factory doesn't mean they can be operational sooner. And they have much smaller generating capacities than full-size reactors.

I also despise the fact that we're using nuclear power not to power homes and businesses but to feed the A.I. hype.

The credulous A1 cheerleaders here must feel very proud.

Just because these SMR's are built in a factory doesn't mean they can be operational sooner.

The entire point of building them in a factory is to reduce delays with the building process. This will reduce the work required down to building the containment building; which is not actually required for operation; it's there as protection against somebody ramming an airliner into the reactor and damaging it.

And they have much smaller generating capacities than full-size reactors.

The RR SMR design which won the competition produces 470MW and is going to be build on a production line, with a unit price of ~£1.8 billion a unit.

Sizewell A was two Magnox units producing 210 MW each = 420MW.

Sizewell B is an AGR unit powering 2x 660MW turbines rated for a total of ~1200MW.

At £1.8 billion per unit, you could build ten for £18 billion with an output of 4700MW; 1/7th of the nations total energy requirements which currently come from biomass (burning trees) or gas generation. The sooner the better IMO.

Due to USA being stinky place that cant be trusted, UK needs own nuclear detergent, like France has due to own nuclear power plants and the waste they produce. Useful for the bombs.

As for who will pay? Why do big tech and co only pay for what they use? If they think they will suck up every Mw for their porno and hate barns they better pay for the Nuclear power plants as well.

Make themselves useful for a change.

#justsayn'

At present Thorium is a potentially interesting R&D project, not something that you can build a commercial reactor for to keep the lights on.