Wrestling with wording like this is always hard 🙁
If the FFS doesn’t want to limit itself to aneutronic fusion advocacy specifically, then I’d suggest that simply prioritizing/emphasizing “clean” and “safe” would be sufficient. (I’m presuming that the reason the FFS would want to advocate for aneutronic is precisely because it has those qualities, and not just because it is aneutronic.) If you want to advocate for fusion in general, I think it would be a mistake to explicitly mention aneutronic in the bylaws, as that would immediate raise the hackles of those pursuing other methods. I think that everyone, regardless of technological preference, wants the cleanest and safest alternative (all things being equal), and so emphasizing those would be a “neutral” way of promoting aneutronic.