I'm not sure if this is a bug, but just in case it is, I found a way to turn blutonium ingots into yellorium ingots by placing them in an offline reactor and then clicking the eject fuel button. It doesn't crash the game or anything, but based on the fact that blutonium exists, and takes 2 cyanite ingots and a special machine to make 1 ingot of it, I'd wager this wasn't intended to happen. I've tested it with different reactor sizes and layouts, and it doesn't make a difference other than the amount of times you have to click the button to convert a whole stack.

i'm using Tekkit, which is running Mincraft 1.6.4, with Forge 9.11.1.965, and Big Reactors 0.3.0A. if you need to know more than that, feel free to ask.

This is technically a "bug", in that it's illogical, but it's also currently the designed/intended behavior. Blutonium is only implemented as an alias for yellorium, internally.

This sort of thing is what I'l be sorting out in later releases.