If there were an "optimal" amount of radiation for evolution at particular stages, you could imagine that this reactor, which offers a spectrum of radiation fro

If there were an "optimal" amount of radiation for evolution at particular stages, you could imagine that this reactor, which offers a spectrum of radiation from "really bad" to "optimal" to "background" (depending on distance) would be useful. Lifeforms at the optimal distance from the reactor would evolve at a greater rate.