Annular nuclear fuel partition cooling dual-mode space nuclear reactor and spacecraft

The invention provides an annular nuclear fuel partition cooling dual-mode space nuclear reactor and a spacecraft. The reactor is characterized in that the reactor comprises an outer pressure vessel shell, an inner annular shell (10) and a spray pipe (9), annular nuclear fuel is placed in the inner annular shell (10) to form an independent annular nuclear fuel internal flow channel (7) and an independent annular nuclear fuel external space (3), and the annular nuclear fuel internal flow channel (7) and the independent annular nuclear fuel external space (3) are used for forming a cooling working medium circulation loop; a coolant for the nuclear heat propulsion mode enters the reactor core from a nuclear heat inlet pipe (5) at the upper part of the reactor, flows through the reactor core through an annular nuclear fuel internal flow channel (7), and is directly sprayed out from a spray pipe (9) at the bottom of the reactor core to generate thrust, and the coolant for the nuclear power propulsion mode flows in