So, in that case, how did it "discover" it? It just woke up one morning and realised "Hey, I've got a nuclear fusion rocket in my gullet! That would explain the heartburn"? I think not. (It has been a Well Known Fact for some years now that dragons run on fusion power. It had previously been thought they might use fission, but this would require them to eat a large quantity of Uranium and Plutonium. Their staple diet seems to rule this possibility out, as most Beautiful Princesses and Courageous Knights are somewhat deficient in these essential minerals.)
Still, it's better than a Jazz Fusion rocket. There have been some problems in getting enough kinetic energy out of it to be any use.