Pretty much every nuclear reactor that’s recently been built has been crazily over budget and significantly late. It seems it is usually a decade later than planned.

If you look at the EPRs, well, we can thank the Germans who co-developed the project, and pushed for excessive requirements making the design complex, such as the double containment and the system to make maintenance possible without shutting down the reactor. Requirements that the French didn't need or want, but which were accepted as a concession to keep the Germans in the project, before they slammed the door anyway.

Even Okiluoto and Hinkley Point can be regarded as serial entries, so different are they from Flamanville, and so much work had to be done to simplify them.

Let's scrap the EPR design, go back to Gen IIs for now, since we know they're reliable, safe, cheap and easy to build, and move straight on to Gen IV when it's ready.

Anyway, the beginning of construction is a highly misleading timeframe. There’s a long process before construction even starts. Not unique to nuclear reactors.

You still have nuclear power plants, you don't even have to start from scratch. But yes, NIMBYS are a significant problem, but renewables are already facing this problem too, and it's going to intensify greatly with the amount of space it takes to build wind turbines, solar panels, and the colossal amount of storage it takes to make them viable without fossil, hydro or nuclear power.

I dislike nuclear reactor discussions because of similar arguments. E.g. “new technology” fixes some problem, while ignoring the drawbacks

I'm talking about Gen II reactors like the 56 that make up France's nuclear power fleet, which are tried and tested, safe, inexpensive, efficient, and have enabled France to decarbonize almost all its electricity in two decades. I'm not into technosolutionism, I'm into empiricism.

If someone says that it’ll take 15 years then the person didn’t solely mean the actual construction. They mean from wanting it to having it working.

Okay, so the 4 Blayais reactors, totalling 3.64GWe (equivalent to almost 11GW of wind power, but without the need for storage or redundancy) were connected to the grid 6.5 to 8.5 years after the first public survey, made before the project was started.

I'm not claiming that every reactor project will be built so quickly, but we have to stop pretending that nuclear power is inherently slow to build. It's the lack of political will that makes nuclear power slow to build, and it's not an unsolvable problem.

Gen II reactors are the reactors design which has been built between the 70's up to 2000, it has nothing to do with SMRs.

My point was that there's no reason to insist on a ridiculously complex reactor design such as the EPR (which is a Gen III reactor), and that we can simply go back to the proven designs of the second generation for two or three decades, until we finish developing the fourth generation, which has real arguments.

interesting idea, though Chernobyl and Fukushima were both gen2s 💀

The reactor that exploded at Chernobyl was an RBMK model, not a PWR. This implies major design differences from French PWRs, including:

• A positive temperature coefficient, which means that an increase in core temperature leads to an increase in reactivity, which in turn leads to an increase in core temperature, and so on, implying instability and the possibility of a runaway. French PWRs are designed with a negative temperature coefficient, so an increase in core temperature leads to a decrease in reactivity, and vice-versa, physically preventing the runaway that caused Chernobyl.
• A flaw in the shutdown system: graphite rods were used to reduce reactivity during reactor shutdown. On the one hand, these graphite rods descended too slowly into the reactor core, and on the other, they physically increased the reactor's reactivity when they were first inserted, before reducing it. In fact, it was irradiated graphite that burned and radioactively contaminated the whole area around Chernobyl, not uranium or anything else. On french ones, there is simply no graphite, nothing inflammable nor any rods of any sort, it's water that's used to stop the reactors.
• There was also no containment vessel.

Two things to note: the USSR knew about these defects years before the Chernobyl disaster, but the scientists who raised the alarm were neutralized. The other is that the explosion and fire in the reactor were caused by the failure of inexperienced technicians to follow procedures, under pressure from senior management, because the plant was to be visited by a high-ranking official the following day, and therefore the tests they were running at the moment had to be completed at all costs.

Chernobyl exploded because of the USSR's cult of secrecy and appearance, causing incompetence and corruption.

For Fukushima, it should be noted that Fukushima Daini, although closer to the epicenter of the earthquake, but with better safety standards, was only slightly damaged and even served as a refuge for tsunami survivors.

For Daichii, same thing as Chernobyl, we have a very long list of failures and even falsifications by TEPCO dating from 2002, and even more in 2007, with alarms sounded on all sides by seismologists and scientists of all sides, and the government did not react.

We must understand that these are not disasters that happened out of nowhere, that we could never have predicted, and even less that we could never have avoided. It was a very long succession of bad choices by the incompetent and corrupt.

But despite all this, the Fukushima nuclear disaster caused no deaths, and Chernobyl only killed a few thousand people at most. Nuclear power, in its entire history, has killed only a fraction of what coal kills each year.

I guess it could be made more safe cheaply with modern electronics and software (seeing IoT/“AI”/boeing software engineers in a nuclear facility would freak me the fuck out though)

It has already been done, and without AI/IOT or anything of that kind. For the French REPs, this resulted in the implementation of additional testing protocols (I know that they tested accelerated aging over 10-20-30 years of parts like cables, for example), addition of generators, renovation and improvement of industrial parts, etc.

Both Chernobyl and Fukushima could’ve been avoided/reduced in effect with good failsafe software imo.

No. Fukushima Daichi's walls were just not meant to handle more than a 5 meters wave. It took a 14 meters high wave right in the face.

I kinda doubt we’d be able to make gen2s cheaper than gen3s (at least in small capacities) though, because their production lines and designs would’ve been long shut down/forgotten

The industrial fabric has been crumbling for a long time, that's for sure, but at least the designs are much simpler, and we have thousands of engineers working on gen IIs and can contribute their expertise. We don't have any of that on the gen IIIs.