> I'm hoping for applications outside military ship and submarines, which have been around since the 1960's.

I'm referring to military ships and submarines. I'm not really sure where the financial incentive for nuclear comes from for anything commercial?

TBH it seems like you have a culprit (regulation) in search of a victim (nuclear utopia), and as a result, you have a solution (nuclear power) in search of a problem. If that's the case, there are really many much better examples.

> Nuclear test ban treaty, etc.

The NTBT covers intentional detonation of nuclear weapons... I'll be the first to concede that regulation has perhaps hamstrung the private sector nuclear weapons market :-)

> engines for nuclear rockets

Radiation is a bitch and lead is heavy. Conventional rockets that we need for human space flight already can, with modification, get us to where we've wanted to go so far. So we've instead focused our resources on doing useful stuff once we get there. NASA doesn't have inf money.

This is something that people continue to research. What's holding it up is a lack of priority in decisions about what science to fund and a complete lack of any private sector market large enough to justify the investment, not any sort of regulatory barrier.

> nuclear excavation techniques

...I'm having an extremely difficult time thinking of a use case where this would make any sense. Nuclear bombs are more powerful than conventional explosives. That power has an enormous tactical advantage in wartime because you can take out a city with a single missile instead of weeks worth of bombing runs.

But that's not really a particularly beneficial feature in e.g. a commercial mining operation. Plus radiation's a bitch.

Help me out? What are the possible use cases here?

> nuclear airplanes

Radiation is a bitch and lead is heavy.

> I don't see how this is a disagreement with what I was saying. Imagine if society had the same amount regulation on building software systems as dealing with radioactive stuff. Moore's law would not exist.

This isn't clear to me. I think the hardware would've still be invented. Perhaps the business impact would've been smaller, but regulation of commercial software systems wouldn't have stood in the way of the enabling physics and engineering research.

Also, see the Ford quote about Microsoft; if the nuclear industry worked like the software industry, we wouldn't even be here to have this conversation. We'd have BSoDed our way to nuclear Armageddon some time around 2001.

> nuclear power plants had grown exponentially for multiple decades... Why didn't that happen?

Physics is a bitch. More precisely, I'm unaware of any serious conjectures by modern nuclear scientists that there are obvious advances on the horizon that could give us exponential improvements to reactor output even in the short term. Let alone over 3+ decades.

Aside from power, and perhaps inter-planetary travel, nuclear is a case of "tried it, doesn't work for fundamental reasons" or "wtf now you're just throwing nukes on things for fun". And in the case of power, we have a lot of data points from a lot of different regulatory regimes, all of which point to "this is a quite expensive way to make power which won't pay off until fossil fuel externalities are finally internalized... i.e., never"