If you mean fusion energy research, the difficulty is more at the engineering level rather than the nuclear physics, and I doubt the structure calculations are

If you mean fusion energy research, the difficulty is more at the engineering level rather than the nuclear physics, and I doubt the structure calculations are relevant to fusion dynamics. There's doubtless interest in the model calculations, but even in the absence of direct applicability of the physics, there's considerable value just in the practice of high quality experimental science. Many things that pass as measurement or some sort of "science" in computing make an experienced experimental physicist wince, unfortunately.