And I also wanted to ask if I constructed a wall made out of it, with GCRs and SEPs and Neutron radiation (basically every radiation in space) from the other side, how many kgs per m^2 of H-BNNT would be required to bring the radiation levels below the maximum permissible limit? For example, if I constructed a wall out of polyethylene, then it would be 7 metric tonnes per m^2, according to http://space.alglobus.net/papers/Easy.pdf. I want to know this value, along with the density, for H-BNNT. Please cite your sources as well, since I need to reference this.
You might be interested in this paper: Properties of H-BNNT for radiation shielding applications. It briefly mentions how the neutron absorbing properties of the material can be used for radiation shielding in space, but the main purpose is to find a value for the density of it. A simulation approach is used (it is not clear if someone has actually managed to produce the material yet), and the paper concludes with a density of
A definitive value for how many kg/m² of shielding material is very difficult to give any measure for. Firstly, the amount of radiation received at various locations in space varies extremely, secondly, tolerable radiation doses is dependent on mission length, and the properties for H-BNNT for non-neutron radiation seems hard to find.
Finally, bringing mass just to act as shielding is a last resort in space exploration as every gram counts. A more common approach is to use for example tanks of waters or the fuel tanks for that purpose.