Answer:
No
Although microwaves are described as "Microwave radiation" this has nothing to do with radioactivity as used in power stations an atomic bombs. Microwave ovens simply uses the effect of radiowaves on the molecules of the potato to excite them and start them vibrating which generates heat.
The primary problem with microwave ovens is that the energy may not be evenly distributed within the potato.This is why the turntable is used. But even with this is it is possible to leave areas of the food uncooked while the surrounding area is thoroughly cooked.
Secondly with microwave energy it is possible to superheat food to the point where the inside is hotter than the boiling point of water even though the outside may be just warm to the touch. Therefore all microwave ovens and microwave cookbooks recommend a cooling off period before eating, to minimise the risk of scalding your mouth.