Nuclear - future for Ireland?

The actual figures for Korea (from the International Atomic Energy Agency) https://web.archive.org/web/20251201000000%2A/https%3A//pris.iaea.org/PRIS/WorldStatistics/ThreeYrsUnitCapabilityFactor.aspx

2024 79.6%

2023 80.2%

2022 81.7%

2021 74.9%

2020 76.9%

2019 68.4%

2018 64.8%

2017 71.4%

2016 82.2%

2015 84.8%

It doesn't matter how you try to spin it, Korea's nuclear plants had several years in a row with reduced output.

Nuclear is simply not as dependable as you like to suggest.

NY has closed 40% of it's nuclear reactors since 2020. That's not a ringing endorsement.

As for newly built reactors. If a reactor doesn't provide power when it's supposed to you have to pay to get the power via other means (usually fossil fuel). A Chinese EPR was offline for a year. Flamenivlle III only reached 100% output recently. While you might like to suggest that new reactor are more reliable the evidence just isn't there.

Hinkley-C was supposed to produce power by Christmas 2017. Since it won't produce any power until at least 2030 there's 13 years of ZERO % capacity factor. But it's OK , the UK gets a similar amount of power from the environmental disaster that is DRAX.

This reduction in emissions happened despite UK Nuclear falling from over 12GW to under 6GW during this time.

A nuclear power station can't offset emissions when renewables are already doing that. Nor can it offset emissions from the peaking plant it's reliant on to load balance seasonal or daily demand.

https://www.ucl.ac.uk/news/2025/oct/wind-power-delivers-ps104-billion-net-benefit-uk-consumers from 2010 to 2023, How much more could have been saved in Hinkley-C wasn't soaking up funds like a money-pit ?

AFAIK the UK taxpayer isn't paying the direct costs at the moment but are on hoc for billions in guarantees etc. And yes £'s will be extracted if/when it starts up and the cost of wind or solar are below the CPI indexed strike price from the Start Date of Reactor One to 35 years after the Start Date of Reactor Two.

The UK govt let EDF off the hook when they extended the original "long-stop date" where the CFD price drops from 2029 to 2033 when the contract could be cancelled and EDF would have to accept market rates , which would include wind and solar that were no longer on CfD contracts and essentially only have O&M costs.

Flamanville 3 was to have cost €3.3Bn , in 2022 EDF said €13.2Bn, last January the French Court of Auditors estimated €23.7Bn including interest.

With nuclear the cost of financing the project is insane. Look at the interest rates governments can get for bonds and compare that to the interest rate that nuclear projects require because of the risks. Last time I bothered it was something like 2% vs 8% and thanks to the magic of compound interest over 10 years that difference works out at 1.22 vs 2.16 times the original value. Which matches the rule of thumb that nuclear costs double every decade.

The opportunity cost of investing in nuclear also includes having to keep old thermal plants open that could have been shut down.

It's a bit more nuanced, as French renewables produce more power than France exports. And exports peak and dip depending on wind.

https://www.rte-france.com/en/data-publications/eco2mix/power-generation-energy-source# - Without nuclear or gas.

Same graph with exports vs, wind and solar almost all of which was installed during Flamanville's construction and eventual delivery of full power on 14th December 2025.

With nuclear the more you look the worse it gets. I looked up the the full power date and oh-boy it's worse than I thought. Snippets below from Flamanville 3 news from EDF. (translated)

This Monday, February 9, 2026, at 19:28, the unit n°3 of Flamanville has been reconnected to the national electricity grid.It was shut down on January 10, 2026, following the passage of Storm Goretti. - So already missed 90% capacity factor for 2026.

27/01/2026 – Declaration of a significant safety event (SSE) due to the unavailability of a last-back generator for 2 hours

On January 26, the teams conducted a periodic test on one of the two ultimate rescue generators. During the preparation of the test, a shunt necessary for the realization of it was placed on the wrong electric relay. It was immediately brought back into conformity.

27/02/2026 – Declaration of a significant security event (SSE) due to non-compliance with a repair deadline for one of the main generators

From February 8 to 19, the EPR is in production. Work is being carried out under preventive maintenance in power* on one of the four main generators. At the end of the power-effective preventive maintenance niche on February 19, the main generator cannot be put back into service. The general operating rules prescribe a period of 7 days to repair the equipment. This deadline was not met, the main generator set was put back into service on 28/02/2026.

https://www.edf.fr/la-centrale-nucleaire-de-flamanville-3-epr/les-actualites-de-la-centrale-nucleaire-de-flamanville-3-epr/actualite-de-l-unite-de-production-ndeg3-de-flamanville

Friday, March 13, 2026 at 7:40 a.m., the No. 3 production unit of the Flamanville power plant was disconnected from the electrical grid following the automatic triggering of the turbine protections. The power of the reactor was reduced to 20%.

After carrying out the necessary checks, the teams of the plant reconnected the unit No. 3 to the national electricity grid on March 13 at 6 p.m. The event had no impact on the safety of the facilities.

Nuclear is absolutely dependent on backup and spinning reserve. 80% power loss covering business hours on a Friday.

Flamanville 3 is still having teething problems so maybe next year it might deliver on it's 90% uptime ?

Nope there's a 350 day outage scheduled from Sept 26 2026. (And it's not the first EPR to have a year long shutdown after commissioning and I suspect it won't be the last.)

And that means capacity factor for 2027 is totally stuffed too, even if the outage doesn't get extended. Probably isn't cheap either.

Maybe in 2027 , twenty years after the concrete for the reactor's base was first cast, it will have a chance to deliver the promised uptime ? (But it will need refuelling in 2027 / 2028 so don't get too excited)

One week is about 2% of annual demand so we are good until ~2048 because we'll be allowed burn fossil fuel although that's only in the case that ALL other generators and interconnectors are offline and there's no other storage available. ( By limiting when it's used fossil fuel can act like last resort storage. )

And for the Nth time no one is looking at batteries for long term storage despite your repeated strawmaning. We already have Hydro, Biogas , Biomass, CHP and incinerators. By 2048 we will also have Fuel to energy , Tidal and possibly Geothermal and a lot more offshore wind which has a greater capacity factor and wider geographical spread.

Besides to go nuclear we'd need to massively increase renewables because we'd need to provide power during the ~20 years it would take to get a nuclear plant up and running. Doing that would eliminate demand for nuclear.

In order to prepare for nuclear you have to prove you don't need it.

Hinkley Point`s 3260MW plant with a capacity factor of 94% will generate 3064MW. For £35Bn. that is £11.42Bn. (€13.22Bn.) per GW.

It's now £49bn ( €56.7Bn / €18.5Bn per GW ie. already more than your wind farm ) and they've already lined up another £1bn if it's delayed yet another year.

Besides your costs are way off because the operating EPR's don't operate at 94% capacity factor or anything close to it. 85% might be a better target even if it's only been reached in 1 in 4 years of operation.

94% capacity factor in any reactor is a pipe dream except if you measure 12 months in middle of an 18 month fuelling cycle. When you take maintenance and refuelling into account no reactor can do that more than three years in a row. Add in unplanned outages or delays in restarting and there's a reason why NPP's only average ~80% globally. And that doesn't include construction delays or early shutdowns.

94% ? The reality is that 50% of the EPR's completed so far have year long outages after commissioning. Flamanville 3 will be off line for a year (350 days) from 26th September.

Taishan-1 started operation in 2018 and was then taken offline from June 2021 to August the following year.

which still doesn't explain the 4.113 TWH and 2.068 TWH supplied by Taishan-1 in 2022 and 2023

A 1.6GW reactor should produce 14TWH a year. OL3 isn't remotely close to 94% - In 2025, the total production of Olkiluoto 3 was 10.38 TWh, showing an increase over the previous year (9.69 TWh). ( 74% and 69% )

Please explain how you could even get 94% when there's outage times like this ???? The annual outage at OL3 did not take as long as originally planned. The outage was scheduled to take 63 days and continue until 2 May. The actual duration was 59 days and 10 hours.

The other completed EPR is Taishan 2 - World Nuclear Association it doesn't produce 14THw per year or anything like 94% of that every year either