Molten fuel nuclear reactor with neutron reflecting coolant

A molten fuel nuclear reactor comprising:

• a containment vessel and vessel head;
• a reactor core enclosed within the containment vessel and vessel head, the reactor core having an upper region and a lower region;
• a first heat exchanger enclosed within the containment vessel and vessel head, the heat exchanger configured to transfer heat from a liquid fuel in the reactor core to a primary coolant;
• a neutron reflector containing at least some neutron-reflecting liquid;
• and
• a circulation system that circulates the at least some neutron-reflecting coolant in the neutron reflector.