Also one area it would be good to push the gov on

He hinted the government was keen to offer consumers lower bills if they lived close to new obtrusive nuclear construction.

Interesting - will the gov also allow communities with their own renewable energy sources to benefit from lower bills too? My understanding is community projects like a village wind turbine benefits the community by earning money for them, but I suspect more communities would back them if they could instead provide lower energy costs

 

will the gov also allow communities with their own renewable energy sources to benefit from lower bills

And have Scotland's leccy bills lowest in the UK?

Methinks not😉

 

Lower bills, lol! Why is not happening already? Torness and it's surrounding 1000's of windmills which blight the landscape...

 

I really can’t get excited about preparing for SMRs when they are basically still vapourware at this stage. There are no actual products to buy. There is no economic case to be made for any of those products as yet. No site requirements etc.
Any preparation involves a lot of speculation of what exactly we might be preparing for given that no product made it to market as yet.

 

I really can’t get excited about preparing for SMRs when they are basically still vapourware at this stage. There are no actual products to buy. There is no economic case to be made for any of those products as yet. No site requirements etc.
Any preparation involves a lot of speculation of what exactly we might be preparing for given that no product made it to market as yet.

I agree currently SMR’s clearly aren’t commercially available, and equally it may be they never appear

but I don’t think that takes away from this being good news, I think everyone would agree the UK has a serious problem with planning and construction, so taking steps now to prepare for SMR’s should they become viable is a wise move IMO

 

After I recovered from the initial heart attack reading the headline (thinking it was a plan for more Hinkley C’s) I feel this is welcome news.
...
obviously there is no commercial SMR available, but when they do appear I can see the advantage of having them located across the UK in locations of high energy draw (like the suggested AI datacentre sites) and so see this pre-emptive move as a good one

None of this will actually happen, certainly not in our life times.

Firstly there's good engineering and safety reasons why the location of nuclear sites is rather restricted. Nuclear power generation uses a steam-cycle and their thermal efficiency isn't that high, so they typically need access to large amounts of cooling water, which generally means needing to be located near large rivers, estuaries, coastal sites. There are ways around that, but they come with their own draw-backs.

Like any industrial facility there is a risk of accidents and the impact will affect the area within a radius around the plant, that risk is lower and more manageable when the radius is lightly occupied - agriculture, small villages, limited development. That's why the existing nuclear plants are, with a few exceptions, generally well out of the way. Put a nuclear plant next to a major urban area, if there is an incident then that's a major problem. And of course there's the on-going risk once the site reaches the end of its life, we already have urban areas blighted with land contamination from the old coal / town-gas plants, old industries etc. Do you really want a still radioactive, decommissioned nuclear facility on the edge of your city, for the next 100 years?

But ultimately what will stop it that key thing - cost. The nuclear industry started with small reactors and soon found they weren't economic, which is why it started making them bigger because as you scale up the size, the output increases but the costs increase at a slower rate than the output, making them more competitive. But they still weren't economic so the designers made them bigger still. The current generation of large nuclear was meant to be economically viable, competitive with gas and coal, it wasn't and it isn't, so now the industry is going into reverse hoping that small modular will work. But none have been built yet, they're all 'paper reactors' just designs and ideas, the costs only become apparent when they go into manufacture and construction.

Hyman Rickover on Nuclear Designs

Hyman Rickover on Nuclear Designs

www.powermag.com

 

Hyman Rickover on Nuclear Designs

Hyman Rickover on Nuclear Designs

www.powermag.com

Hadn’t come across this before. Seems well observed.

“An academic reactor or reactor plant almost always has the following basic characteristics: (1) It is simple. (2) It is small. (3) It is cheap (4) It is light. (5) It can be built very quickly. (6) It is very flexible in purpose (’omnibus reactor’). (7) Very little development is required. It will use mostly off-the-shelf components. (8) The reactor is in the study phase. It is not being built now.

“On the other hand, a practical reactor plant can be distinguished by the following characteristics: (1) It is being built now. (2) It is behind schedule. (3) It is requiring an immense amount of development on apparently trivial items. Corrosion, in particular, is a problem. (4) It is very expensive. (5) It takes a long time to build because of the engineering development problems. (6) It is large. (7) It is heavy. (8) It is complicated.”

 

SMRs are never going to happen.

 

We have had quite a lot of SMRs in service for decades, now, so what's the problem? They are proven technology, and so far have been shown to be safe over all those years.

 

But not for electricity production.
The problem is the lack of a viable business plan in a competitive market, or an actual product, or a particularly persuasive market opportunity.

 

But are they economical outside of a military setting, obviously for the nuclear deterrent money is not the deciding factor or we'd have binned it years ago. Can those designs stand on their own in a commercial setting? And if so why haven't they?

 

That's the big question, but in their favour is that pretty much all of the development and certification cost has already been paid (via the government funding every class of nuclear boat we've ever built).

These reactors are now fuelled for a 25 year operating life, but that life will be predicated on the sort of utilisation in a boat. On land, running 24/7, that life probably reduces to around 20 years, at a guess. These reactors cannot be refuelled, so that will be the end of life for the core. The big question is whether the cost of the core can be recovered by 20 years of generation or not. TBH I just don't have a clue, as I don't think the actual costs for any of the parts of the programme have ever made it into the public domain.

 

SMR costs a lot, and conventional Nuclear was already the most expensive, so that might slow down deployment...

 

SMR costs a lot, and conventional Nuclear was already the most expensive, so that might slow down deployment...

My understanding of the aim/concept for commercial SMR’s is that they will be considerably cheaper than it is now - part of that would be from having a standard design and central factory manufacturing them. That’s still a concept however

I will note however that I feel that it might be worth accepting an element of slightly raised expense for SMR’s in exchange for their ability to provide a base load and balance to the GRID. Again strongly believe that we need to focus on renewables for the grid, but with some of the challenges still around some of the larger plans of green hydrogen plants for example which are also (if I understand correctly) not yet up to the scales needed for our Grid plans

To take a specific example, I’d happy back plans to use SMR even if there was a higher cost (within reason) of it meant ending our need for gas turbines

 

The naval ones aren't big enough. I don't know what size they are @Jeremy Harris might know but if he told you he might have to kill you...! I think the problem is they do need to upscale the ones used in the subs. And the problem with everything nuclear is that upscaling gets you nearer to the critical mass all the time.

 

They are big enough for the proposed SMR use case, which is to provide distributed generation close to places with a high continuous demand. I think this was key to the RR proposal, that they could reduce grid distribution costs, by putting these things wherever there was a high demand.

The problem will inevitably be the siting of them, though. I can see getting planning consent for one of these things taking decades.

 

I have a problem now. 20 MW equals 1.5 big wind turbines. Double that for average capacity and all of a sudden the maths don't stack up. I just wish that RR could do the job. And whilst 20 MW is a useful amount of electricity we really need 15 GW of cheap nuclear power to shut up all the naysayers.

 

I think the chatter I've seen talks about 50-100MW as the size range for commercial SMRs, which may help explain the money distributed for development work.

 

A thousand 20MW reactors dotted around the country could solve many problems.

The military designs are able to be ramped quickly, so considerably change the dynamic on power control/energy storage.

RR has disappointed me with their overly cautious approach to new designs. I don't mean disappointed because of following 'tried and trusted' engineering to get to an outcome, that is good and perfectly respectable. But they are almost deliberately trying not to push the state of art.

Again, one can view that in two ways, but they could at least 'try', they still have the established designs to fall back on. I suspect the reason for not doing so is that if they did so, they fear they might simply end up help develop tech that someone else picks it up and then competes with them on.

Every dramatic and sudden paradigm change needs to be delivered in small steps ... but most people don't see the small steps.

 

A thousand 20MW reactors dotted around the country could solve many problems.

The military designs are able to be ramped quickly, so considerably change the dynamic on power control/energy storage.

RR has disappointed me with their overly cautious approach to new designs. I don't mean disappointed because of following 'tried and trusted' engineering to get to an outcome, that is good and perfectly respectable. But they are almost deliberately trying not to push the state of art.

Again, one can view that in two ways, but they could at least 'try', they still have the established designs to fall back on. I suspect the reason for not doing so is that if they did so, they fear they might simply end up help develop tech that someone else picks it up and then competes with them on.

Every dramatic and sudden paradigm change needs to be delivered in small steps ... but most people don't see the small steps.

One other benefit is less the cost of making 'the reactor', but more all of the piping / valves / anciliary bits around the reactor.
For something in the gigawatts, all of that'll be custom-castings, custom made, at tremendous cost.

But when we're down at this level, do we reach the point where an increasing count of these components become almost off-the-shelf? "1x steam valve for a 1 foot wide pipe, up to XX bar? Yes, 72 of those in stock, sir, more coming next month".

Similarly, we might elect to not scatter them around the country as you suggest, but have (say) 20 of them in the same area.
That way, a shutdown at one means we're at 19/20; near enough the same as full power. Today, a shutdown of a gigawatt reactor is pretty painful for those managing the grid.

All of this to say: I'm all for it.

 

This is all part of an overall strategy, and no one is saying we will definitely deploy SMRs.
The Government has been reasonably consistent, at least in the last few years, on the need to have an actual energy strategy and define milestones on the journey to the interim 2030 state and final 2050 state.

The SMR stuff has been trundling along for a few years, and is part of the NESO future strategy - at least as an optional element.

A quick search of gov.uk shows a few relevant items including details around investment and/or development costs.

Advanced Nuclear Technologies

www.gov.uk

How the Environment Agency is assessing new nuclear power station designs – Creating a better place

As the UK government takes forward its plans for a low carbon future, the regulators of the nuclear industry, the Environment Agency, Office for Nuclear Regulation and Natural Resources Wales are currently assessing three new nuclear reactor designs. Teams of

environmentagency.blog.gov.uk

The ongoing SMR programme stated at the back end of last year
"The four companies, GE Hitachi, Holtec, Rolls Royce SMR and Westinghouse, have been shortlisted following two rounds of assessment by GBN, the government’s expert nuclear delivery body.
GBN will negotiate with all four before final tenders are submitted, with final decisions to be taken in the spring".

This means we will know more within a few months on what will be taken forward, if anything.
To that end, the PM is just laying the foundation to support any decisions that come out of this stage.

We need to do more in parallel with what we're doing with off-shore wind. Other renewables get us some of the way. But I don't see how we materially reduce burning gas in large quantities when renewable generation is low without some other form of power generation. Current or planned large-scale nuclear isn't the answer due to massive costs and delivery timescales. So we need something to add into the mix, alongside everything else we're doing on grid upgrades, interconnects, more renewables, etc.

 

We need to do more in parallel with what we're doing with off-shore wind. Other renewables get us some of the way. But I don't see how we materially reduce burning gas in large quantities when renewable generation is low without some other form of power generation.

Agree - large scale green hydrogen is often floated as a solution to this but my understanding is that technology is similarly some way off being scaled up to a level when it can do that - so it makes sense to hedge bets on green hydrogen and SMR’s to remove our need for the gas turbines

 

Alternative views;-

"
Activist response

Stop Sizewell C said: "The words 'nuclear power' and 'rips up rules' do not belong in the same sentence. Given that not all the sites in the existing National Policy Statement are suitable for nuclear reactors, this further relaxation of planning rules is deeply concerning.

"We refute the government's attempts to blame campaign groups for delays and cost increases at Sizewell C.

“You only have to look at Hinkley Point C (now £46bn in 2023 money and 5 years late) and EPR builds in France and Finland to realise that these projects can generate massive delays and overspends all by themselves.

“Sizewell C was expected to make a Final Investment Decision in 2022 but has still not done so, primarily because there do not appear to be sufficient private investors willing to fund it."

Greenpeace UK policy director Doug Parr said: “The Labour government has swallowed nuclear industry spin whole, seemingly without applying so much as a pinch of critical scrutiny or asking for a sprinkling of evidence.

“They present as fact things which are merely optimistic conjecture on small nuclear reactor cost, speed of delivery and safety.

“Which is courageous – or stupid – given that not a single one has been built, and with the nuclear industry’s record of being overtime and over budget unmatched by any other sector.

“And as for the unsolved problem of nuclear waste management, government don’t see the need to mention it at all.

“Meanwhile there’s a renewables revolution taking place across the planet using established technology that is continually coming down in price, and can already deliver secure energy at lower cost than fossil fuels.”
"

Nuclear sector rejoices as Starmer slashes red tape and enables plants to be built anywhere | New Civil Engineer

In a bold move, Starmer’s government will make a number of planning reforms to allow nuclear energy generation projects to pass through the system easier.

www.newcivilengineer.com

 

Okay, why SMRs will never work and will fail.

First, forget naval reactors. The Navy isn't looking for something that is commercially viable, they will pay what it costs. They use fuel that isn't available for civilian use due to proliferation, and which is also very expensive. You can't just take a reactor out of a ship and stick it in a building either, so adapting those designs is a massive amount of work.

SMRs have all the same problems as larger reactors, and more new ones. If we look at the NuScale design, since that is the closest to starting to build a prototype, they need a cooling pool. The pool has to be disaster proof, because if it drains you get a nuclear meltdown. You still need a containment building too. So do you build a large pool and containment building and put lots of SMRs in it, or do you build lots of smaller pools and containment buildings? Neither is a good option, both are expensive, and it scuppers the idea of having lots of distributed reactors all over the place. Because you can't just have a containment building, it needs to be guarded, have isolation around it, controlled airspace, all that stuff.

Then there is the waste. NuScale admitted that their reactor would produce more waste than a conventional one, per watt-hour generated. So that means even bigger cooling pools, more very long term storage. All adds to the cost.

The idea is that having a production line for the reactors will get the costs down, but it won't. I mean the reactor vessels might be a bit cheaper to make that way, but because they are smaller you need more of them, more material per watt-hour.

That's all before you get to regulatory approval, and the nightmare scenario of finding a flaw in the design that needs to be corrected across hundreds of working reactors, instead of dozens.

In the very best case it's going to be a couple of decades before prototypes are proven, approved, and production starts. We haven't got two decades, we need solutions now, and besides by then renewables and battery storage will have replaced everything. And SMRs are no different to full size reactors, they don't integrate well with renewables because they can't rapidly adjust their output or idle for long periods, at least not profitably. We will end up with mostly renewables and probably some gas plants to cover a few days a year.

 

Okay, why SMRs will never work and will fail.

First, forget naval reactors. The Navy isn't looking for something that is commercially viable, they will pay what it costs. They use fuel that isn't available for civilian use due to proliferation, and which is also very expensive. You can't just take a reactor out of a ship and stick it in a building either, so adapting those designs is a massive amount of work.

SMRs have all the same problems as larger reactors, and more new ones. If we look at the NuScale design, since that is the closest to starting to build a prototype, they need a cooling pool. The pool has to be disaster proof, because if it drains you get a nuclear meltdown. You still need a containment building too. So do you build a large pool and containment building and put lots of SMRs in it, or do you build lots of smaller pools and containment buildings? Neither is a good option, both are expensive, and it scuppers the idea of having lots of distributed reactors all over the place. Because you can't just have a containment building, it needs to be guarded, have isolation around it, controlled airspace, all that stuff.

Then there is the waste. NuScale admitted that their reactor would produce more waste than a conventional one, per watt-hour generated. So that means even bigger cooling pools, more very long term storage. All adds to the cost.

The idea is that having a production line for the reactors will get the costs down, but it won't. I mean the reactor vessels might be a bit cheaper to make that way, but because they are smaller you need more of them, more material per watt-hour.

That's all before you get to regulatory approval, and the nightmare scenario of finding a flaw in the design that needs to be corrected across hundreds of working reactors, instead of dozens.

In the very best case it's going to be a couple of decades before prototypes are proven, approved, and production starts. We haven't got two decades, we need solutions now, and besides by then renewables and battery storage will have replaced everything. And SMRs are no different to full size reactors, they don't integrate well with renewables because they can't rapidly adjust their output or idle for long periods, at least not profitably. We will end up with mostly renewables and probably some gas plants to cover a few days a year.

This.

Little more needs to be said - except that few other countries think they need nuclear in their future mix. Why would the UK, with a brilliant distribution of wind plus interconnects, need nuclear when other European countries don't?

 

Might as well announce a series of cold fusion plants too, they've also got about as much likelihood of ever being built

 

Wave generation is about 10 years behind Wind but could be something to watch. Our local University in Lancaster is a centre for excellence based on the fact that Morecambe bay is one of the worlds best places for wave generation, and has been researching the potential of TALOS, see link below.

https://www.lancaster.ac.uk/engineering/research/talos/

 

Unless the data centres are going to pay most of the costs of these to guarantee supply, these will represent terrible value

 

This is the thing... the wealthier companies become. like big tech, the less resources are left for us. So now it's power.

 

The NESO 2030 plan (or the various paths we can take to achieve that plan) all assume big nuclear still exists at pretty much the same levels as now, after we retire some older sites and bring on some newer ones. At least from my skim reading of their various articles.
That sort of makes the case that NESO does not believe SMRs are a factor in the short term. And in the timeframes we're talking about that makes perfect sense.

What I don't see anywhere is something that joins all the various elements of renewables and grid upgrades, interconnects, etc, and shows the year-by-year view on investment costs vs renewable energy generation so that we can see that any plan for 2030 is viable.

I care that we burn less stuff, the sooner the better. I don't massively care how much it costs because we need to do something to ensure our continuation as a species on this pale blue dot. We have high electricity prices in the UK, and if we have to keep paying at higher rates for a few years more to get the right energy generation in place, then that is fine because we will ultimately benefit from cheaper energy, just delayed by a year or three.

I can sort of see how we get where we need to be from the off-shore wind. For everything else, it's almost as if it is opaque by design on what will be deployed where, with what technologies, plus grid improvements, and interconnects with friendly neighbours that are ensured as being from renewable sources (or big nuclear in the case of France).

The only decent-sized (350MW) battery storage near me that is planned is currently at risk because of a multitude of objections and concerns over the environment, wildlife, impact on people, etc, plus how it will interfere with the proposed Rampion 2 scheme and cabling. In theory, it is approved, but the reality is there is an overlap with Rampion 2, and that isn't approved. It is a chicken-n-egg problem.

Edit: The Rampion 2 decision was due 6th Feb, but has been put back to April. Not clear on exactly why, but BBC has a local news article about it here.

 

I think it is also a bit of a stretch to try to portray countries like France and Finland as embracing new nuclear. They have both been badly burnt by the expense and delay in their EPR projects.

Also, the claimed advantages of SMR production seem plausible in principle, but there is a reason we have ended up with big reactors: thermal and fuel efficiency generally get better with scale. And many of the SMR proposals are slowly creeping up in scale.

I'm not impressed by claims that the UK's power consumption needs sub-GW unit scale reactors to avoid problems when a single unit drops out. It isn't like the UK is a small power consumer with no links to anywhere else... average consumption is 35GW. There are plenty of things that can go wrong to take a couple of GW out of action (lines or existing big plant going down) so we just deal with it.

 

And where does the fuel come from-- Russia
Where does the waste go longterm --- no one seems to know

You cannot build nuclear alongside RE as it is not capable nor financially viable to ramp up and down.

At times we are already 100% zero CO2 and that is with exports and wind curtailment. Nuclear just means more curtailment and increased costs for the most viable tech. There is no business case for nuclear not now,not ever.

The cost of solar,wind and storage continue to fall. Its peanuts to do solar and can be done in days not yrs. The solar has little transmission costs over and above what we alredy have.

Must go the bloods boiling.

 

The fuel doesn’t come from Russia. The UK has been making its own nuclear fuel since the start of British nuclear power at Springfields.

We have our own fuel fabrication and enrichment facilities and more plutonium than we know (knew) what to do with. Unfortunately the government has decided to throw our 140 tons of it away by encapsulating it in ceramic for geological disposal, rather than using the enormous amounts of energy it could produce in reactors.

The only reason we don’t have a long term storage solution is people keep objecting to it. So all the high level waste people are so scared of, because they don’t understand it, is kept in temporary storage facilities where it actually poses more risk! Now an enormous amount of potential clean energy is going to be made unusable and made into a larger volume to simplify storage until the inevitable geological storage facility becomes a reality, because all the foot dragging about nuclear power means we don’t have reactors to burn it off in.

A link on the topic, though it’s easy to search: AMR developer ‘disappointed’ by government’s decision to immobilise plutonium stockpile | New Civil Engineer

 

There are studies out there of mixes of VRE and nuclear: adding nuclear to the mix, and thus reducing VRE capacity, reduces the total amount of curtailment (because there's less variable stuff that can't be dispatched on demand!).

In that sense, the kind of generation that increases wind curtailment the most is ... more wind, whose output is heavily correlated with existing wind.

 

There are studies out there of mixes of VRE and nuclear: adding nuclear to the mix, and thus reducing VRE capacity, reduces the total amount of curtailment (because there's less variable stuff that can't be dispatched on demand!).

In that sense, the kind of generation that increases wind curtailment the most is ... more wind, whose output is heavily correlated with existing wind.

I guess the key thing is that if we add nuclear… it isn’t going to happen anytime soon… the next 5 years at least and probably decades… so really it’s going to be being added to a grid that is already essentially decarbonised.

The way I see it to be viable in the future, already very low carbon, energy mix, a generation source has to either be lower cost than renewables or it has to be good at ramping up and down to fit supply to demand when renewables leave a gap.

So far I really cannot see how SMRs help but maybe I am missing something. Doesn’t seem that likely to me but perhaps they can provide power for £10/MWh?

 

 

Ah I do love the Juice Media. Public service broadcasting at its finest.

 

51% of the WORLDS electricity comes from Renewable Energy and now i am told we need nuclear. We only need to do another 50% and the costs have plummeted to a fraction of what they were.

In the UK there is a pipeline of RE much greater than is needed, its already there.

The Nat Grid back along told us that by 2025 they could run at net zero CO2 and we have if only for a couple of hours so far.

When HPC is finished the cost of its electricity will be c 3X the cost of RE. This is madness.

 

@donald (and anyone else who wants to play “fantasy national grid”), if you were given a budget of, say, £100bn a year for the next 25 years to make the UK grid as sustainably green as possible by 2050, how much of the budget would you allocate to nuclear, what energy generation mix would you be aiming to end up with, and what would the resultant average LCOE be?

(you are allowed to borrow money to invest more money up front, but the repayments and interest must be paid from the £100bn; perhaps assume 0% RPI and 3% interest rate for the purposes of discussion?)

 

I'll play, but you need to tell me what the rate of £.over-night/kW, £.maintenance/kW and £/kWh.year is, and if there are any storage options we are allowed to buy in, again the £/kW and £/kWh.

If you indicate the peak GW daily demand to deliver with that £100bn, too.

Would you like me to ask deep-thought to give me those values, or offer your own?

 

I just guided an answer and asked for its 'opinion' so as to optimise total annual energy using £100bn.

I suspect it guessed at a split between wind and nuclear because it came to the same split with and without maintenance drawn from the £100bn, but it is a starting point, and includes some data values;

£100bn installation costs, maintenance not included;-

Question	Nuclear	Wind
Installed cost (£/GW)	~£6-8 billion	~£2.5-4 billion
Annual maintenance cost (£/GW/year)	~£50-100 million	~£40-80 million
Total kWh per GW per year	~7.9 billion kWh	~3.5 billion kWh
Optimal spend from £100 billion	£60 billion (7.5 GW)	£40 billion (13.3 GW)
Total annual kWh (for optimal spend)	~59 billion kWh	~46.5 billion kWh
Typical peak power output per day	7.5 GW	~10-13.3 GW
Lifetime (assumed)	25 years	25 years

Maintenance included;-
Updated Table (Including Maintenance):

Question	Nuclear	Wind
Installed cost (£/GW)	~£7 billion	~£3.25 billion
Annual maintenance cost (£/GW/year)	~£75 million	~£60 million
Total maintenance cost over 25 years (£/GW)	~£1.875 billion	~£1.5 billion
Total cost (installation + maintenance) over 25 years (£/GW)	~£8.875 billion	~£4.75 billion
Optimal spend from £100 billion (installation + maintenance)	£60 billion (6.76 GW)	£40 billion (8.42 GW)
Total annual kWh (for optimal spend)	~53.4 billion kWh	~29.5 billion kWh
Typical peak power output per day	6.76 GW	~8.42 GW
Lifetime (assumed)	25 years	25 years

 

I just guided an answer and asked for its 'opinion' so as to optimise total annual energy using £100bn.

I suspect it guessed at a split between wind and nuclear because it came to the same split with and without maintenance drawn from the £100bn, but it is a starting point, and includes some data

…

Maintenance included;-
Updated Table (Including Maintenance):

Question	Nuclear	Wind
Installed cost (£/GW)	~£7 billion	~£3.25 billion
Annual maintenance cost (£/GW/year)	~£75 million	~£60 million
Total maintenance cost over 25 years (£/GW)	~£1.875 billion	~£1.5 billion
Total cost (installation + maintenance) over 25 years (£/GW)	~£8.875 billion	~£4.75 billion
Optimal spend from £100 billion (installation + maintenance)	£60 billion (6.76 GW)	£40 billion (8.42 GW)
Total annual kWh (for optimal spend)	~53.4 billion kWh	~29.5 billion kWh
Typical peak power output per day	6.76 GW	~8.42 GW
Lifetime (assumed)	25 years	25 years

Those figures show the price per generated kWh over the 25 years to be 4.5p/kWh for nuclear and 5.4p/kWh for wind, right?

On that basis why would the optimal split be 60:40? Why not 100% nuclear?

On those figures, for £100bn spent on nuclear you could build and maintain 11.27GW of capacity, and generate 89bn kWh pa - rather than the 82.9bn kWh for the 60:40 split.

Perhaps you need to ask deepseek to check its workings for the optimality of the split?

Or use a spreadsheet rather than an LLM!