@argv_minus_one I mean, the following text literally appears verbatim on their website. It's not like they're trying to hide it.
Because it is the only facility that can create the conditions that are relevant to understanding the operation of modern nuclear weapons, NIF is a crucial element of the National Nuclear Security Administration’s science-based Stockpile Stewardship Program.NIF can repeatedly simulate those conditions inside the Target Chamber’s controlled environment, giving dedicated teams of scientists and researchers the ability to reconstitute and improve upon the capabilities of underground testing.
NIF’s high energy density and inertial confinement fusion experiments, coupled with the increasingly sophisticated simulations available from some of the world’s most powerful supercomputers, increase our understanding of weapon physics, including the properties and survivability of weapons-relevant materials.