A lot of recent suggestion threads have gone something to the tune of "X is not realistic, we should change it to be more realistic". However, that is not a valid argument. The Powder Toy is just that- a fun game about powders, solids, bagels and electrickery, not about being a real simulator. URAN is not meant to be like real life, fissile uranium- it's just a pressure to temperature converter, and DMND is just meant to be an indestructible uberelement for e.g. containing fusion, resisting acid. These elements aren't going to be changed, because thaousands of saves have already made use of these specific properties.

If you want to add new functionality or enable a new style of reactor to be made, the only real way to do it is through adding in a new element. At no point has realism been a priority, rather it gives a framework for the addition of elements- their names are only meant to give a recognisable identifier for them and a general idea of their properties, not scientifically define their exact nature.

No. It shouldn't. Do you have any idea how many saves would break because of a change to a fission mechanic? It's always been a temperature generator from pressure, that is its one and only function. It was never, ever meant to be an accurate uranium analogue. Does it make sense in the real world? No. It makes sense in TPT, however, since it was basically designed for bombs and pressure reactors, which it does very well.

Can it be changed? yes, but the marginal advantage of realism is far outweighed by the loss of a) backwards compatibility, and b) a simple pressure-->temperature converting element.