It wasn't for political reasons at all. The reactor design - EPR - was specifically designed to be a large reactor[1].
Paradoxically this large-reactor approach was intended to reduce costs but has spectacularly failed to do so with cost overruns of factors of 3 (in this case) and over 5 (from Flammanville).
I'm doubtful of that. One big root cause for most of the delays is the fact that no new reactor projects were started in a long time before this one, in Western regulation regimes. Due to this, a lot of cumulative experience was lost from the industry and the designs become outdated. For example all the previous designs relied on relay based automation, which is no longer available. Add to that the increasing demand of safety, necessitating way heavier structures and yet again obsoleting designs.
I would think building another one like this should be less of an ordeal. Too bad the sister project at Flamanville was started too early after this one to benefit from the lessons learned.
No it's almost a rule to build reactors in pairs. That way when you maintain the other, the other still outputs energy. When the decision was made Green Party was in the cabinet and they had made a promise not to build any more nuclear power. So a compromise was made and to actually meet the energy demands of the Finnish industry, the biggest possible reactor was chosen.
I'm not disputing that there were politics involved in choosing to build one instead of two reactors. What I mean is that the many of the big challenges facing this project were not particularly connected to the power of the unit. Any size of a reactor would have had the challenges with strict regulation, new type of automation, lack of experienced personnel, etc.
In Finland (and a lot of other places) building the reactors as pairs is not that necessary due to large fluctuations in the power consumption over the seasons. Basically you just do all the maintenance/refueling during the time of the year with least electricity demand (summer in Finland)
> One big root cause for most of the delays is the fact that no new reactor projects were started in a long time before this one
There have actually been quite a few new reactors brought online in the past two decades in France, the UAE, Russia and Belarus. This is a brand new design though, and construction was started in multiple countries at similar points in time.
Only France of those is under the Western regulation, and even though they did bring a couple of reactors online in the beginning of 2000s, those projects were started at least 30 years ago, using designs from before that. Hence, for example the burden of verifying that industrial digital automation can be made nuclear regulation compliant lied on the EPR project.
Hence they had to build one ginormous reactor, facing numerous issues caused by venturing into the limits of maximum power per reactor.
Had they permitted 4 * 400MW instead of 1 * 1600MW, the plant would have been in production for years already.