Plutonium at Fukushima?
Bearing in mind Japan's militaristic past and blazing hot technological economy, plus the Macarthur constitution and Old Nippon's extraordinary willingness to adopt nuclear power despite being A-bombed into submission at Hiroshima (the U.S. version of history is very self-flattering), doesn't it make sense to speculate that Japan (or more likely Mitsubishi) has conducted a few science experiments over the years with its own self-preservation in mind, rhetorical question mark?
See, plutonium doesn't naturally occur in Nature. (The nastiest isotopes of the stuff in the air come from nuclear weapons testing in the 1960's; or possibly, in Japan, a special case, from Pu-239 weapons use in 1945, Nagasaki.) You need a breeder reactor and the will to go where no one should go, not to mention the tenacity to learn how to make the stuff.
I'd give dimes to doughnuts that one or more of the zaibatsus either have The Bomb or the wherewithal to make one quickly. Japan, as a sovereign independent nation, almost certainly “does not.” But the zaibatsus are the Seven Jewels of the Imperial throne, and will remain demurely out of sight until and unless they're needed.
Plutonium at Fukushima? I dunno. "Intent" depends on which isotopes were found in Fukushima's soil. Plutonium has "industrial" uses, but only Pu-239 is weapons-grade; still, the Seven Sisters Hypothesis might make a good world holocaust prevention flick. (Not starring Angelina Jolie this time, please. How about Dakota Fanning instead?)