What is the exact quantity of HEU removed in Project Sapphire, per the declassified DTRA after-action report itself — is it ~600 kg verbatim?

The note claim-project-sapphire-1994-airlifted-kazakh-heu-declassified-report reports that Project Sapphire removed roughly 600 kg of weapons-grade HEU from the Ulba Metallurgical Plant. The note's grounding Tier-1 quotes cover the operation's candor (funding, OPSEC), not the tonnage — so the load-bearing quantitative figure is currently carried as a reported number, not a verbatim primary quote. The sourcing floor wants a specific number grounded in Tier 1–2.

Why it matters. The figure is what makes Sapphire a materially significant tributary of Megatons to Megawatts rather than a footnote. Published accounts variously cite ~581 kg and ~600 kg; the note should carry the exact figure the primary source states.

What would answer it:

1. Read the DTRA after-action report. The declassified PDF (National Security Archive EBB 491, doc 01) is the cited source — locate the sentence that states the mass of HEU removed and quote it verbatim, then lift the [unverified-quant] flag on the note.
2. Cross-check. Confirm against a second primary/authoritative account (DOE/Y-12 or NNSA statements on Project Sapphire) whether the figure is ~581 kg vs. ~600 kg and record which the note should use.