A nuclear reactor core (1) for a molten salt nuclear reactor (100). The nuclear reactor core (1) has a tubular cylindrical center moderator vessel (10) for passage of a liquid moderator (11), a cylindrical fuel salt jacket surrounding the center moderator vessel (10), and a cylindrical neutron reflector jacket surrounding the cylindrical fuel salt jacket, wherein the cylindrical center moderator and neutron reflector vessel (10) has a largest inner cross-sectional area medially between a liquid moderator and neutron reflector inlet (12) of the center moderator and neutron reflector vessel (10) and a liquid moderator and neutron reflector outlet (13) of the moderator and neutron reflector vessel (10).