Nuclear rocket engine with pebble fuel source

Abstract

A nuclear thermal propulsion rocket engine. A source of fissionable material is provided in a bed of fuel pebbles located in a reactor. A fluid having neutron moderating constituents, such as hydrogen and/or carbon, therein, is provided, which may be in the form of methane, or ethane, or a combination thereof, or may further include various isotopes of hydrogen. An external neutron source is provided using a neutron beam generator. Reactor design geometry provides containment of fissionable material, and for any byproducts of fission reactions, in the reactor during acceleration of the rocket. Impact of neutrons on fissionable material results in a nuclear fission reaction conditions in the reactor, resulting in release of heat energy to fluids provided to the reactor. The reactor is sized and shaped to contain fuel pebbles containing fissionable material, and to confine expandable fluids as they remove heat from fuel pebbles. the heated fluids are discharged out through a throat, into a rocket engine expansion nozzle for propulsive discharge, The design provides a rocket engine with a specific impulse in the range of from about eight hundred (800) seconds to about twenty five hundred (2500) seconds.