Main reason to use Co-60 instead of any other fuel - GT6 is too easy (for me). So I make nuclear fuel much harder to get, especially in current world. Only then Co-60 becomes good. Hint: there are centrifuging recipes for depleted fuel rods. For example, depleted Co-60 fuel rod gives 12/72 U-238.
If I put a screenshot, nerfs will come. So no 
Nothing blocks radiation currently. If you want to get rid of damaging debuff, remove IC2.