There's something of a paradox in Brexiteers' complaints about how much being in the EU interfered in their lives, but seem convinced that it basically will take at most a week to clear off and be entirely separate. Really? I'm not suggesting that the UK can't survive without the EU, but the transition isn't exactly going to be smooth, is it?
With respect to NJ's point about how other countries can survive without the EU, that's true, but then they weren't a part of it to start with. I think a good analogy might be to think of conjoined twins, or some such: it's obvious that one person can survive on their own, and doesn't need a second person attached to them, but still: separation of conjoined twins is an operation that's fraught with risks and can go horribly wrong, because they weren't two separate people to start with and had become rather co-dependent as a result. It can also go right, and both twins lead perfectly happy and healthy lives separated, but if you just grabbed a chainsaw and cut the two apart in a few seconds it wouldn't end so well.
But anyway. Euratom is a complication I was only vaguely aware of, and I'm not therefore going to go on about how crap it's going to be now that we are leaving it, but like all other Brexit questions it deserves respect and to be taken seriously.