NNSA does pay into the broader ECP (which refers to the whole supercomputer program not just Frontier) but they aren't the only contributor. Like I said, DoE do

NNSA does pay into the broader ECP (which refers to the whole supercomputer program not just Frontier) but they aren't the only contributor. Like I said, DoE does build supercomputers for stockpile maintenance missions. Those computers will be built with basically all NNSA money and probably little to no Office of Science money. AFAIK some amount of NNSA money went into building Frontier specifically but it was earmarked under their non-stockpile missions. NNSA doesn't only design/build/maintain weapons they also are responsible for nuclear security missions. For example, they provide the R&D that backs US support to the IAEA. They are funding a limited amount of unclassified, non-weapons work being done on Frontier in support of their other missions. The key point is that stockpile maintenance is firewalled, both in terms of funding and operations, from the other stuff and they are not the only contributor. DoE has always been a "big tent" of separate missions and I totally understand how it gets confusing. Its predecessor the AEC also had a weird mix of practically orthogonal goals. The non-weapons and non-nuclear missions have gotten a lot bigger in the last 30-40 years and are more or less operated independently of each other. NNSA is also functionally an independent agency within DoE, but it's important to note that they do fund pure science work too, with non-weapons related goals.