I have a minor issue with the removal of the tokamak, its too cool to remove, could it come back to replace the generic 'magnetic confinement reactor' used for magnetic confinement drives ?
Afterall it is a magnetic confinement reactor itself, and even the previous stellarator is also a magnetic confinement reactor,. It might introduce some confusion to people familiar with previous tech levels though. In fact maybe some of the other generic reactor types could be renamed.
Improved Pressurized water reactor - Pressurized Heavy water Reactor
Improved Nuclear Thermal Engine - Liquid Core Nuclear thermal engine
Improved Pebble bed - Molten Salt Cooled Pebble Bed
Improved Nuclear Pulse Engine - Liquid Metal Core Nuclear Pulse Engine