More Nuclear Propulsion Engines and Fill function in Simpleplanes

Simple Rockets 2 current only has Nuclear Thermal Rocket from NTR and only two mediums, liquid hydrogen, and water.
So, I highly wish that more conceptual nuclear propulsion systems such as the fusion engine, fission segments engine, or nuclear saltwater engine can be developed, and these will greatly help the players to develop their knowledge in nuclear reaction applications, also the creativity of constructing rockets in a new style.
Although some people may wonder that the occurrence of nuclear propulsion will make the game too sci-fi and irrealistic, this phenomenon takes part when any brand new technologies occur, and the one with great bravo and ambitions will succeed. Furthermore, I believe that more nuclear propulsion will make SR2 more attractive.
Lastly, I also wish to have the function "Fill" in simple planes because it really helps us create the rockets with different shapes really easily.