thats the fuel that you put into your reactor, you need some thats used enough that its processable

I thought the fuel rods were made from uranium... Odd that I have all green check marks on the storage options and it is full of chemfuel, but no plutonium.

Any ideas?

you have to load spent fuel into the plutonium processor for it to process, burn up some fuel in the reactor until its marked as processable in the fuel info panel in the reactor console, then remove it from the reactor and load it into the pu processor