Yeah, I wasn’t thinking of the code being proprietary, but the data. One of my friends is a nuclear engineer, and as an undergraduate student she had to pass a background check before the DoE would mail her a DVD containing high-accuracy data on measurements of nuclear material, because that’s not shared publicly. Not my background, so I don’t know precisely what the measurements were, but I imagine data on weapons grade materials is protected more thoroughly than the reactor tech she was working with.