Hmn.... Radioactive Magical Girls? I think I may have some of those in my encycopedia but considering how so many things have been researched and even retconned, I think that my old knowledge might had been scrapped at some point due to the tweaking.
Lets see..... *Opens Book*
I think I may have a few about this but they aren't given much power as an actual magical girls but I can write a origin story of two points.
Firstly, the pure scientific magical girl which should be born in Japan(Mostly because it had been seen to be hit by nukes in the past). A magical girl's generation is made due to the radioactive genetics passed from one point to another. As such, a magical girl could be born however its powers would solely be based on scientifical logic. For start, she can fly by using the chemicals she could excrete from her body(Like her foot could release a cemical formula for fuel and firestarter as trusters), her magic beams are made through heatrays that she can fire from her wand(something through heating a material from her wand), she radiates radioactive beams from her body and can change the chemicals through lethal and non-lethal attacks. I don't think she has the 'magical' flare since the magic I explain closely relates to science and being creative with her magic is needed a thorough research on the scientific field(more on chemistry). I do think she can be a magical girl but she'll be at most a dangerous threat than a hero in my case(you can make her a comedic point but it could be hard). On my point, it is possible to create a magical girl, just that she doesn't have tha magical aspect.
the second point is a mutation which in my case is also possible since we have an example(fantastic 4). However, it would mostly be a one trait skill which limits her 'magic' aspect as in the first one. Elemental magical girl is possible through her powers correlates to an element. Another is through chemical secretions she possesses, using a wand as a conduit to fire special beams that either paralyze her opponents, mutate her enviroment or even possible to be used as biogical healing tool of toxin if controlled well. As for this origin story, this would be most based on a special radioactive chemical, mixed with a genetical gene or element and its possible to create such a magical girl.
My point is that, while I think it is impossible to recreate a 'magical' girl, you can tweak her powers and the scientific powers she possesses that would be made to create a magical girl through radioactive or nuclear waste....
*Closes book*
I think I have given my point of view as I am currently thinking how the fck is my encyclopedia this thick and has a wide array of stories I actually don't know. So, please excuse me for I'll be booking a therapy for tomorrow.