So, i know that during nuclear fission, a heavy particle is split into two smaller ones that have a higher specific binding energy. And i know that a certain amount of mass is transformed to energy for the binding. The same thing happens during nuclear fusion. However, from my intuitive (and probably wrong) point of view, one has to put energy INTO the atom in order to make one with a higher binding energy. My reasoning is this: binding energy = the amount of energy to build the atom from scratch (i.e. moving the nucleons piece by piece from infinity to the fm-sized shell). So, if the binding energy is higher, more energy is required to put the atom together or rip it apart. So, wouldn't it make sense to go from a high binding energy state to a lower one, so as to RELEASE this binding energy? It just doesn't make sense to me that energy is RELEASED to go to a high bound state. For instance, in atomic physics, an electron releases energy (an x-ray) when going to a lower binding energy-state. I'm a bit confused despite having understood this for years in the past.... can anyone help?