Therefore, its known narrative elements are not a part of the Doctor Who universe. It may have been the basis for a similar story in another medium, however — and that story may indeed be a part of the DWU.
Project Zeta Sigma was an unproduced serial that would have been the first story of the Fifth Doctor. It would not have carried on straight from Logopolis. It would have featured nuclear disarmament, but John Nathan-Turner claimed that it would not work and Castrovalva replaced it. (REF: Doctor Who - The Handbook: The Fifth Doctor)