How do I describe what I do for a living w/o boring or confusing women?

To put it simply I try to avoid telling women what I do for a living entirely to begin with until I "know" them, so this is not a TMI thing.

I don't often having a problem making small talk with girls during courtship but of course the question of, "what do you do?", comes up. I try to just nip it at the root and just say I'm a mechanical engineer and not elaborate further, but this is rarely satisfactory for her.

I do design engineering for replacing mechanical/HVAC equipment in nuclear power plants. I do some cool stuff like walking down plants, travel, etc., but trying to explain this in a way that doesn't bore, or at best, confuse the woman I am talking to is a real challenge.

I always try to keep it concise but usually get 20 Questions when I mention this and it never ends well.
"Do you absorb radiation?"
"That's cool whats HVAC?"
"Oh... so what does that mean?"

Is there a way I can improve my communications regarding my job and not fall into this trap? Is it best to just maintain mysterious/ambiguous with it? Should I lie about it in a way that has plausible deniability?
Or maybe I should change careers and have something more attractive?

Thanks!
How do I describe what I do for a living w/o boring or confusing women?
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