There may be an existing module to do that, I haven't checked, and I would be a bit surprised that it did not exist, but if not, it should be quite easy to write one, this is really quite easy math to compute half life calculations. Once you have done that, you just need to call the module functions. I am not a nuclear scientist, but I think I know enough about these things to be able to come up with a module skeleton to implement at least the basic calculations. If nothing exists, I would be happy to take this as a challenge, Please ask if nothing exists.