Could an electron emitted by beta decay of a neutron on the sodium hit the nucleus of something else and combine with a proton their to form a neutron, producing an unstable isotope of that something else?
Electron capture by a nucleus is a thing, but as far as I know, this only happens to any significant extent to unstable nuclei that naturally decay that way. It’s probably possible for a high enough energy electron to hit a stable nucleus and convert a proton to a neutron, but I’ve never heard of it (although I’m not an expert). So I don’t think anyone needs to worry about this.
