Unfortunately, the answer is that currently the survey feature does not have an option to prevent a user from taking the survey more than once.
It would not be difficult to add that functionality for authenticated users. For anonymous users the best you could do is prevent them from taking the survey more than once during a given time window like 5 minutes based on ipaddress.
I will look into this when I get a chance, but right now I'm very busy.
Best,
Joe