Internal-external hybrid microreactor in a compact configuration

An apparatus comprising:

• an internal-external hybrid nuclear reactor comprising:
• at least one reciprocating internal engine configured to receive internally a nanofuel comprising:
• a molecular mixture,
• wherein the molecular mixture comprises:
• a plurality of components mixed together, wherein at least one of said plurality of components comprises a molecule, the plurality of components of the molecular mixture comprising:
• i) a fissile fuel, wherein the fissile fuel comprises:
• a nuclide that undergoes neutron induced fission;
• ii) a moderator, wherein the moderator comprises:
• an element capable of:
• A) thermalizing a neutron population;
• and
• B) absorbing a fission fragment kinetic energy;
• and
• iii) a passive agent, wherein the passive agent comprises:
• a nuclide comprising:
• a resonance neutron absorption cross-section in an epithermal energy range,
• wherein said resonance neutron absorption cross-section of said passive agent, creates a neutron sink that increases with a nanofuel temperature;
• and
• wherein the plurality of components of the molecular mixture provide the nanofuel a nanofuel negative temperature coefficient of reactivity;
• and
• at least one external nuclear reactor integrated with said at least one reciprocating internal engine.