Ludwik Kowalski says typical Pu from a power plant is only 60% Pu-239. This
means that to produce weapons grade material one must use some kind of enrichme
nt process like gasseous diffusion or centrifuge similar to the enrichment
of uranium. Although starting at 60% instead of less than 1%, as with U-235,
is a big advantage, in principle the technology must be similar enought that if
one can do Pu they can probably do U, so why the big concern over Pu?