I wanted to write a student article specially for those who don't have a background in nuclear physics. I've been suggested to share my basic understanding & ask if they're correct.
I would be grateful if anyone could explain where my mistakes are:
(Please note that diagrams are designed just to give a simple imagination of the article & make it more understandable; they do NOT correspond precise information.)
In fusion reactions, lighter nuclei are combined into heavier ones (atomic mass increases); so the direction is from left to right (shown on the diagram). Therefore, in the fusion of 'light elements' the total final binding energy is higher (the related arrow points upward); so ##B_2-B_1>0## and energy is released. But for the fusion of 'heavy elements', the reverse is true, so ##B_2-B_1<0## and energy is needed.
In fission processes, heavier nuclei split to lighter ones (atomic mass decreases); so the direction is from right to left. Thus, in the fission of 'light elements' total final binding energy is lower (the arrow points downward); so ##B_2-B_1<0## and energy is utilized. But according to the arrow pointing up, the fission of 'heavy elements' is exothermic.