Based on other comments here, I did a little digging on Wikipedia, in case others with zero background (like me) are curious.
This appears to be a nuclear thermal rocket [1] which would use a nuclear reaction to directly heat propellant (e.g. hydrogen) that is ejected.
This is different from a nuclear electric rocket [2] which would produce electricity which would then generate propulsion [3] using a smaller quantity of propellant, e.g. using an ion thruster [4].
It is also different from a fission-fragment rocket [5] where the nuclear fission products themselves are ejected for thrust directly.
This appears to be a nuclear thermal rocket [1] which would use a nuclear reaction to directly heat propellant (e.g. hydrogen) that is ejected.
This is different from a nuclear electric rocket [2] which would produce electricity which would then generate propulsion [3] using a smaller quantity of propellant, e.g. using an ion thruster [4].
It is also different from a fission-fragment rocket [5] where the nuclear fission products themselves are ejected for thrust directly.
[1] https://en.wikipedia.org/wiki/Nuclear_thermal_rocket
[2] https://en.wikipedia.org/wiki/Nuclear_electric_rocket
[3] https://en.wikipedia.org/wiki/Electrically_powered_spacecraf...
[4] https://en.wikipedia.org/wiki/Ion_thruster
[5] https://en.wikipedia.org/wiki/Fission-fragment_rocket