Nuclear Powered Aliens

[Varyon]

Reading through the GURPS Space description of Bioroids, my mind went off on a tangent that I'd like some advice from the forum on. The "aliens" in my Harpyias setting, the Malakim, are engineered organisms, albeit distinct from "true" bioroids in that most of them are produced via reproduction rather than assembled. I've long wanted them to be highly resistant to ionizing radiation, and indeed I'd like for them to utilize radiosynthesis to augment (and in some cases produce) their normal rations. The bit in Space about bioroids incorporating synthetic materials made me consider the idea of the malakim actually having radioactive materials in their bodies.

The problem, however, is that one of the ideas behind these creatures is that they don't create. Their bioships are actually just a different form they are able to take, not really technology (they all start out as grubs, and later metamorphosize into one of many forms, including one that eventually grows large enough to serve as a bioship), and any technology they are seen to use is either stolen or purchased from humans. As the humans of the setting are heavily averse to nuclear technology, the malakim aren't really going to have access to good radiation sources.

So, how should I handle this? I've considered allowing a partial exception to the "do not create" rule to allow them to mine and refine raw materials (typically with assistance from human technology), which they can then trade to humans for technological goods. Might they be able to use this technology to purify naturally-occurring radioactive materials, then use those to make better radiation sources in something akin to a breeder reactor? This seems a bit too counter to the "do not create" rule, honestly. What other options might there be? Background radiation out in space might be able to help keep a bioship and her crew fed (bioships, and some other morphs, are also photosynthetic), but that gets rid of the idea of having radiation sources in their bodies. What about occasional visits to gas giant moons, which I understand tend to have very high levels of ionizing radiation? Might such moons contain more useful radiation sources they could consume to incorporate them into their bodies? Obviously you can't mine, say, Cobalt-60 on a terrestrial planet, but if it were possible to mine that (or some other radiation source with a good W/g ratio of radiation power) on a gas giant's moon, it could be workable for the malakim.