> What is the goal of NIF?

Nuclear weapons, more specifically stockpile stewardship (what happens as weapons age) and verification of weapons codes/simulation software (can we make new weapons without full-scale testing).

Everything else is gravy. There's a reason it's at one of the weapons labs (vs. the unclassified work done at most other national laboratories).

The thing you are missing is that in addition to fusion power research (which is valuable and NIF has made major contributions to) there is also fusion weapons research. Inertal confinement is (kinda) close to the conditions inside a fusion bomb, and NIF also has a mandate to research those conditions. For that kind of research, a single pulse of fusion ignition is exactly the kind of data they need. Since we have a nuclear weapon test ban, and computer simulations need some kind of ground truth to be calibrated against, achieving fusion ignition in a lab is valuable to NIF for that reason alone.

In terms of the NIF's broader goal, as opposed to the specific goals for their ICF work, the NIF is meant to keep nuclear physicists fresh on research relevant to nuclear weapons design in the aftermath of the end of the Cold War and Comprehensive Nuclear Test Ban Treaty. [1]

[1] https://en.wikipedia.org/wiki/National_Ignition_Facility#NIF...

The NIF is a facility for conducting experiments. The goal for the field is fusion power, and these experiments may wind up contributing toward it, but it will never be anything more than a stepping stone. The primary purpose of the NIF is validating computer models for simulating nuclear reactions. These models are used both for the design of nuclear weapons and nuclear reactors. They also develop technologies to support their activities, such as new sensors and laser control methods. Compare this program to say a mars rover where we don't expect the rover itself to do anything of great practical utility, but the lessons learned along the way have many potential applications both directly for future missions, and indirectly for spinoff technologies.