Here my plan for the next features. I'm thinking to add a Fusion Reactor to make more use from the Helium-3. For that I would use 'Used Uranium Fuel Cells' as an ingredient. To be able to get these cells faster I would also add a Breeder Reactor which uses the Uranium Fuel Cells way faster but with less efficiency. Need to check and try what is possible here.
Used Uranium Fuel Cells don't make a lot of sense for fusion reactions though. Fusion's point is to combine atoms of a higher energy state into a lower energy state. Fission's point is to take atoms of a higher energy state and to split them into a lower energy state. The fuel and inputs for each process are absolutely opposites and have no overlap whatsoever (like you can use fusion to fuse certain atoms to make iron and get energy out, but you can't split iron to get energy out as it would require putting more energy in to it).
For the future I would also add way more powerful Steam Turbines so that the footprint gets smaller and the UPS impact gets smaller.
A single larger turbine or heat boilers would be great for UPS, just remember that bob's and madclown mods add new tiers as well, so building upon their higher tiers to make more UPS efficient setups would be very useful.