This came up once before, and I didn't answer it then because I couldn't locate precise numbers. I still can't, but common sense says that all the radioactive material processed and concentrated by mankind adds an insignificant amount of heat directly to the Earth's atmosphere compared to that added by the billions of tons of natural radioactive material in the core of the Earth that keeps it molten.

If we are talking only manmade heat sources, the heat resulting from the use of energy from all power sources--and it all ends up as heat sooner or later--would also dwarf the heat resulting directly from manmade radioactive material decaying in the atmosphere.

It goes without saying that all of the above sources, even the internal heat of Earth, are not significant as a source of atmospheric heat compared to the sun.

To put it more simply, you are worried about the effects of a cigarette lighter while standing in the middle of a ten thousand acre forest fire.

Don't sweat it.