In the United States? Virtually no risk.
The worst disaster the United States has had with a nuclear plant was Three Mile Island back in 1979. The radiation release to the public was so low that they couldn't measure it. They had to guess what they thought was released, and that guess was minimal. Taking a commercial flight for an hour would give you more radiation.
But that scared people, and since then the US has really stepped up their rules and regulations. Internally, I would consider the systems foolproof. The only concern is something external causing chaos... and American reactors have dealt with flooding, earthquakes, minor explosions, etc, without issue. We don't hear about those much in the news because there's nothing to report.
If you're worried about daily radiation release, don't be. That's minimal. If people live in Colorado at a higher altitude, then that would increase daily radiation dose far more, and no one ever thinks about that. It's almost irrelevant, and not at all damaging.
Ultimately it's up to you, but I see no reason for worry. If it's something that will forever bother you, then don't stress yourself out, and search for a new house.
I'm female; I've worked at nuclear reactors. I don't have any children, but I'm very well trained on precautions for pregnant women in the nuclear field. If you live twenty miles away you will be just fine.