When removing the Cooling tower with Cut.
The mod Realistic Reactors Reborn (2.0.5) caused a non-recoverable error.
Please report this error to the mod author.

When removing the water tower with Cut.

Error while running event RealisticReactorsReborn::on_tick (ID 0)
LuaEntity API call when LuaEntity was invalid.
stack traceback:
[C]: in function 'index'
__RealisticReactorsReborn/scripts/on_tick.lua:1088: in function 'update_cooling_tower'
RealisticReactorsReborn/scripts/on_tick.lua:326: in function <RealisticReactorsReborn/scripts/on_tick.lua:31>

thanks for the report :)
did you deconstruct them with a mod or on the space platform?
in that case i have added a fix

No just on navus, i just CTRL+X and it crashed.

Is it fixed now though?

yea no issue so far.