Using a nuke does have some aspects of losing your virginity, doesn't it? There's no such thing as a semi-virgin. But that is exactly as it should be. Any nuclear weapon detonated anywhere (except deep underground) will contaminate the environment, although the amount of contamination can vary enormously depending on how its done. A small nuke used for a specific limited military purpose (like relieving the French garrison at Dien Bien Phu, which was actually proposed)crosses a sort of Rubicon, the next time will be a LOT easier, especially if the other side has them.

Even a perfectly harmless application serves as a test, it demonstrates a working system, or one that needs more work (like the N Korean squib). It's not the pop, its the program that's threatening.

The peaceful uses of nuclear explosions I believe are very limited, digging a sea level canal through the Central American rain forest was one I heard seriously considered. What could they have been thinking? People have talked about some fracking applications, but I think that idea is starting to look less appealing lately. The main problem with that type of application is that the harder we look, the more interconnected and interdependent the environment proves itself to be. It's impossible to predict what will happen when we do something really big. Even if the system recovers and heals, it may not be the same, there will be unforeseen consequences.

Still, look at Antarctica. Some day, we may have to move a lot of ice in a hurry...

There is one more consideration. Most of the nukes tested during the Cold War weapons development tests were in remote locations: deep underground, barren deserts, out at sea. The negative effects were isolated, and collateral damage, such as fires, were kept to a minimum. We tried a few in deep space, with unforeseen consequences.
With nukes, consequences are usually unforeseen.

But Orion, yes, that was really something. I would sign up for that mission. The interplanetary environment is already saturated with radiation, a little more would not hurt.