And the radioactive materials that are on Earth, they do what? They decay, releasing heat! Or do they start decaying only after we put them in a plant?!? All of that heat will be released. Taking a minuscule part of the material, generating electricity from that heat and then using the energy to do work (which of course is not 100% efficient but nothing is) DECREASES the heat load of the planet. Just like what you claim about solar. Radioactive materials decay releasing heat all the time; they are an ever present source of heat, just like the sun. Converting part of that heat into work HELPS!
You are like the fifth "nerd" here that keeps bang about heat load like a damn parrots while obviously being supremely ignorant about it. Are you sure you are not that one guy, posting anonymously?
Dude, to top it over, they say the heat from the radioactive decay is what keeps the stuff below our feet liquid and thus creates the protective magnetic shield around the planet! Without radioactive decay there is no life, brother!