[pfdietz]

> let's hear how to change

One approach would be to reduce the size of the containment building by greatly reducing the volume of steam it must hold. This would be done by attaching Filtered Containment Venting Systems (FCVS) that strip most of the radioactive elements from the vented steam in case of a large accident.

The containment building is a significant cost driver, costing about as much as the nuclear island inside of it.

If such a system had been attached to the reactors that melted down at Fukushima exposure could have been reduced by maybe two orders of magnitude. And if the worst case exposure is that low, perhaps much more frequent meltdowns could be tolerated, allowing relaxation of paperwork requirements elsewhere.

[epistasis]

Interesting! Would that require any regulation change?

[pfdietz]

I believe the NRC currently requires that the containment remain leak-free for 24 hours after a design basis accident.

Now, I have not checked if shorter lived radioisotopes would ruin the idea I'm suggesting. It's possible.