Does a primary source document the specific reciprocal on-site monitoring under Megatons to Megawatts — Russian monitors at Portsmouth/Paducah, US monitors at Seversk/Ozersk/Novouralsk/Zelenogorsk?

The note claim-two-verification-regimes-sensor-vs-inspector-govern-the-same-fissile-material-lifecycle rests on a specific factual claim: that the 1993 HEU Agreement ("Megatons to Megawatts") was verified by reciprocal on-site presence — Russian monitors permanently at the US enrichment plants at Portsmouth and Paducah, and American monitors stationed at the four Russian blending facilities (Seversk, Ozersk, Novouralsk, Zelenogorsk). The capture attributed this to a mix of EIA / Centrus / NTI material, but provided no verbatim primary quote naming these facilities or the reciprocal arrangement. The EIA "Today in Energy" page grounds the tonnage and reactor-fuel figures, not the monitoring regime.

Why it matters. The whole point of the observation note is the contrast between verification methods (remote radionuclide sensing vs. inspector presence). If the inspector-presence leg is real and well-documented, the contrast is solid; the facility names are the concrete detail that makes it more than a slogan. This is a historical claim that is plausibly uncontested but currently load-bearing and unquoted, so it should be pinned to a primary before the note leaves seedling.

What would answer it:

1. Read a primary/authoritative account of the HEU Agreement's transparency measures — e.g. DOE/NNSA or US State Department fact sheets on the US–Russia HEU Purchase Agreement, USEC/Centrus program descriptions, or NTI's country/program profile — and locate the passage naming the reciprocal monitoring and the specific plant sites. Quote it verbatim, then lift the [unverified] flag.
2. Confirm the four Russian site names and the two US site names against that source; correct the note if the roster differs.
3. If no primary names the sites, downgrade the observation to the general (well-sourced) claim that the agreement used bilateral transparency/monitoring, and drop the facility-level specifics.