LOL at myself. When Fukushima had its incident a while back I thought it might be prudent to be able to check for an increase in radioactive particles. So I bought one of the Civil Defense detectors before I did my homework and realized it actually takes a fairly high level of radioactivity to get the needle to move. So I bought a different model designed to detect much lower radioactivity levels. That big yellow thing was designed to check for radioactive fallout following a nuclear weapon exchange, not the low levels you associate with leakage from a reactor across the Pacific.

Since you are concerned, maybe consider getting a detector that can measure low levels and take a reading where you currently live and then take readings near where you are thinking about moving. You'll probably find there's not much difference.