Radioactive bees are bees part of the Nuclear Branch, that are from the Extra Bees add-on for the Forestry mod.
Breeding radioactive bees is very difficult as each step of the Nuclear line has a 5% chance to upgrade, each evolution resets the genome to minimum fertility, and the Unstable effect makes monitoring them very dangerous.
Radioactive bees have a dominant effect trait called "Unstable". An effect that damages mobs and player in a rapid fashion for 2 hearts regardless of difficulty and armor, with the exception of the aparist's suit. This effect can kill those even in full quantum armor very quickly.
Mobs will ignore the damage done to them from the bees. Endermen will still do their usual roars as they're being harmed, but won't teleport away. The drops are unaffected by "Unstable", making a mob farm with this effect quite possible...
Radioactive bees produce barren and radioactive combs (2%). Radioactive combs can be processed in a centrifuge for a 50% chance to give uranium ore. It can be used as an alternative of getting uranium besides mining for it, although the process is pointlessly slow(1.3 hours per comb) using default genes(slowest) and an empty Apiary.
With a maxed out Alveary, it is possible to get very high amounts of Uranium Ore. A "fastest" radioactive bee using 5 frames can create about 180 ore per reactor cycle. This is more than enough fuel for most nuclear needs.