Evolution of the Nuclear Type

[Kuribat]

I don't believe Nuclear type could ever be integrated in a regular ecosystem. They emit radiation so if any, they would contaminate everything. Moreover, I don't really understand some of the strength/weaknesses you gave. For example, being weak to bug and normal makes no sense for a Nuclear Pokemon, it would actually be the other way around. In addition, you said nothing about the Steel type, yet Steel is a very radiation resistant material
However, I do like some of the Nuclear evolutions you mentioned. Some of them are rather weird, but others, such as Grimer/Muk, makes sense.