The problem is one of proportion. Yes, radioactive elements create heat. Yes, some of the heat in our atmosphere is due to radioactive heating.

The thing that no one seems to be able to get across to you is that radioactivity accounts for such a microscopic fraction of the total heating influences on the atmosphere that it is totally lost in the noise.

People did the numbers for you, and it didn't soak in. Take it or leave it.

Or assume that the atmosphere is going to fly off the Earth, and behave accordingly. I recommend building a gigantic pressurized dome miles across. Preferably using hand tools.

Try using common sense. The immensely greater natural heating forces on the atmosphere have been acting on it for billions of years, and yet, whaddaya know, it's still there.

So if the sun and other natural heat sources aren't going to drive the atmosphere off, how is the tiny amount of additional heat generated by nuclear power (which is itself only a fraction of the manmade heat generated by combustion processes) going to do it?

It is as frustating as hell to deal with people who need mathematical proof that the Rock of Gibraltar is bigger than a basketball. Some things are just right in front of you.