I'm getting the impression the problem isn't any particular regulation, but rather than because regulations exist, the design is fixed.
Getting a design approved means a specific design is approved. So, the power plant must be built as designed, no changes. And apparently ensuring you built exactly what the design specifies is really expensive.
What's needed to reduce this cost is having some way to get a whole cloud of closely related designs approved, so that reasonable deviations from the design are also approved. This is equivalent to saying only the most critical part of the design would need to be built as designed, everything else would be allowed some slop. With something like this, one might (for example) be able to build the confinement building with less tight control on the configuration of the reinforcing steel.
I'm don't know how one would get such a cloud of designs approved. Maybe this is a problem that could be solved by massive computation? Run billions of mutant designs through a simulation gauntlet to see how sensitive it is to various perturbations? Or maybe add more defense in depth, like devices that scrub radioactive elements from steam (such things exist) so the tolerable chance of meltdown can be allowed to increase while keeping expected damage in check?
Sounds kind of like hyperparameter search - you're searching the design space for the bounds of the different parameters. I don't know if parametric design is possible on reactors, but would be neat if possible.
Getting a design approved means a specific design is approved. So, the power plant must be built as designed, no changes. And apparently ensuring you built exactly what the design specifies is really expensive.
What's needed to reduce this cost is having some way to get a whole cloud of closely related designs approved, so that reasonable deviations from the design are also approved. This is equivalent to saying only the most critical part of the design would need to be built as designed, everything else would be allowed some slop. With something like this, one might (for example) be able to build the confinement building with less tight control on the configuration of the reinforcing steel.
I'm don't know how one would get such a cloud of designs approved. Maybe this is a problem that could be solved by massive computation? Run billions of mutant designs through a simulation gauntlet to see how sensitive it is to various perturbations? Or maybe add more defense in depth, like devices that scrub radioactive elements from steam (such things exist) so the tolerable chance of meltdown can be allowed to increase while keeping expected damage in check?