Plutonium In Fuel Rods: Cause For Concern? : NPR About 6 percent of the fuel in reactor No. 3 at the Fukushima Dai-ichi nuclear plant in Japan is made of a "mixed-oxide" fuel, which contains plutonium — which stays hazardous for tens of thousands of years --as well as uranium. But it does not signif 03-16-2011 by elizabethjames Tags cause, concern, fuel, plutonium, rods