Hydrogenated Boron Nitride Nanotubes are being developed with the general aim of being used in various areas of radiation protection, including the hulls of spacecrafts. I am not qualified enough to answer this from a perspective of science, but for fiction, here is a reason why it is prefect for your requirements.
There are competitions called space settlement design competitions, where high school students collaborate to make somewhat feasible designs for a future settlement in space. Locations vary from Mercury to Low Earth Orbit to the surface of Mars. However, HBNNT is a not-so-commonly used material in these competitions, and often makes a proposal stand out because of its unique qualities. I am often in charge of the materials section in my team while designing such proposals, and it is a material I have found that is perfect for hull requirements. It is enough to pass scrutiny by a panel of judges who are NASA engineers/scientists, even though we are technically dealing with a mix of fact and fantasy. It should be good enough for your novel. Unless you were actually going to present the idea for construction, I cannot see why using it should be a problem.