You seem to know your stuff. Re my post above: do you suppose that the Bushehr WER could in fact be deliberately run as a Plutonium-239 farm by changing the fuel burn-up rate?
This would appear to be analogous to the effect of a short core-residence time - not enough neutron capture takes place to create the useless heavier Pu isotopes because the flux is deliberately kept suboptimal for energy generation (but optimal for enrichment)?
Maybe - but I don't think so. I don't know of its core's neutronics, but I would think even the minimum flux for criticality would produce interesting anomalies that would make it impractical. However low power and short operation would immediately send up the red flags on the plant.
I'm sure that we've got good folks who have modeled the plant and know the answer. My guess is that the plant can't, but I don't know for sure.