it would be more realistic if you could compress elements. like, f.ex PLUT could be compressed into a solid chunk, then when reacted with neut, it would give of way more energy. the extra energy is from the density and the force used to compress alot of one element. i know this sort of disobeys the law of physics, that solids, liquids and gasses canot be compressed, though it would be interesting to see the actuall effects.
that takes long tho, i just love the concept of compressing something, like, f.ex, in real life, if you have snow, you press that snow with intense force into a ball, that ball will be very very hard to break, you could even call it ice.