Just like assuming a perfectly spherical cow, or a frictionless surface, you can completely ignore the economics, the massive cost and schedule overages to make nuclear work.
Flamanville-3 in France started construction in 2007, was supposed to be operational in 2012 with a project budget of €3.3B. Construction is still ongoing, the in-service date is now sometime in 2024, and the budget has ballooned to €20B.
Olkiluoto-3 is a similar EPR. Construction started in 2005, was supposed to be in-service in 2010, but finally came online late last year. Costs bloated from €3 to €11B.
Hinkley Point C project is two EPRs. Construction started in 2017, it’s already running behind schedule, and the project costs have increased from £16B to somewhere approaching £30B. Start up has been pushed back to 2028 the last I’ve heard.
It’s no different in the US, where the V.C. Summer (2 x AP1000) reactor project was cancelled while under construction after projections put the completed project at somewhere around $23B, up from an estimate of $9B.
A similar set of AP1000s was built at Vogtle in Georgia. Unit 3 only recently came online, with unit 4 expected at the end of the year. Costs went from an initial estimate of $12B to somewhere over $30B.
Note that design, site selection, regulatory approvals, and tendering aren’t included in the above. Those add between 5-10 years to the above schedules.
That’s just not true. The Westinghouse AP1000 was given type approval in 2011. It’s what is referred to as a GEN3+ reactor. A lot of R&D was put into simplifying the design, reducing the number of pipe runs, valves, pumps etc compared to GEN2 reactors. It also used large sub assemblies that were factory built off-site then moved for final assembly.
In theory they should have been cheaper to build, but they weren’t. Large assemblies that don’t fit together properly need a lot of very expensive site time for rework. There were other issues on top of that, which just compounded the assembly problems. It’s how Vogtle ended up going from $12B to $30B+, and V.C Summer went from $9B to an estimated $23B when the project was cancelled while under construction.
The EPR units from Areva were similar GEN3+and received type approval in the early 2000s. They had similar cost overruns, for similar reasons.
I have strong reservations about SMRs. So far the cost/MW is about on par with traditional reactors while the amount of waste increases by 2 to 30x traditional reactors depending on technology used.
There are reasons why reactors moved from 300-600MW units to 1000MW+ in the first place. The increased output would cover what was thought to be marginal increase in costs. That turned out to be at least somewhat true.