Many ideas like this have been suggested before. And each and every time they have been shot in the head by other users, mods and quite often even Simon himself. The aim of the powder toy is to have a fun simulator that people who do not have a PhD in physics and advanced computer programing can use (though they are still very welcome to play). If all of the nuclear and chemical reaction suggestions on this forum were implemented, the program that this community is supporting will no longer be called the powder toy, it will have to change to something along the lines of: 'The application of space time physics incorporated with multidimensional particle and quantum simulations at a user level interface ... Toy'.
It seems most people on here seems to have a PhD in physics or engineering or is a major coder. I'm an exception. I have a basic grasp of both even though I'm the top of my class in physics.