Nuclear power plants need to be taken offline for multiple weeks to months at a time for refueling and maintenance over their lifespans making them a poor fit for base load without extremely costly redundancy in a small country.
> maintain extremely good uptime
Not from a capacity planning standpoint.
CANDU reactors, for one, can be (and are) refuelled live:
* https://en.wikipedia.org/wiki/Online_refuelling
Every few decades they do need to be refurbished though.
It’s commonplace for maintenance issues at non CANDU reactors to extend the “refelling” downtime. So no, CANDU can’t stay online for decades without maintenance and instead have similar downtime issues. The major benefit is when manufacturing plutonium due to shorter fuel cycles, but overall CANDU reactors are less cost effective which is why adoption fizzled out.
There are several situations:
* refuelling occurs
* maintenance and/or inspection needs to happen
* refurbishment may be desired
Some of these things take downtime, some do not, depending on the design of the reactor and other factors. A blanket statement of "refuelling forces a downtime" is incorrect in many situations. Depending on the maintenance (or inspections) needed, this may or may not need downtime. Refurbishment generally means tearing things apart, so usually means downtime, but if a site has multiple reactors they can be done one at a time, e.g.:
* https://news.ontario.ca/en/release/1006993/ontario-delivers-...
You said 27 days of planned outage is crazy uptime in the world of electricity production. Hydro routinely beats that by an order of magnitude.
Roughly: EPR runs for 18 months, then requires 1-2 months of maintenance (which includes refuelling about one third of its fuel assemblies). A modern coal or natural gas thermal power plant runs 12-18 months, then requires 1 month of maintenance.
Next, I could not resist as other commenters already mentioned it. You wrote: "small country". As the Aussies say: Yeah, no. Italy is 300,000 sq km. That is not small. If compared to the United States, it would be the fifth largest state.
Finally, why does it seem that all discussions about electricity production on HN always devolve into the "Base Load Wars"? For me, it is starting to feel like a meme. (Are there LLM troll bots trained to enter HN discussions and make a bunch of "base load" arguments?) Seriously, can someone please create a text-based role playing game that revolves around a future society locked into eternal "Base Load Wars"? (See: PhD Simulator[1])
I think the problem of the Finns was that they really wanted energy independence and tge inly ones that were on the market were the french. No doubt the frenched used much diplomatic muscle to attract them as a first experiment.
There are 70 countries larger than Italy, Russia is more than 50x the size.
America the 4th largest country is still 20x the size of Italy.