Yeah, it's a lot of radiation.
Just remember, Mother Nature don't give a shit. This universe was not made for your pleasure.
'Course, as somebody pointed out, by that time if we haven't unmade the universe (read The Forever Peace by Joe Haldeman to see what I'm babbling about - but get it at the library, it's a crappy book!) in a fit of self-destructive fury, we'll probably EAT that kind of radiation. :-)
So it all works out in the end.