Nuclear reactor thermal management system

A system comprising

• a reactor vessel;
• an internal shield or vessel encompassing the reactor vessel and defining a first thermally insulative region therein, the internal shield or vessel configured to maintain the first thermally insulated region above a melting temperature of a molten salt during operation of the reactor vessel;
• a reactor enclosure encompassing the internal shield or vessel and defining a second thermally insulative region, the second thermally insulative region being held at a temperature that is cooler than a temperature of the first thermally insulative region;
• and
• a below-grade concrete structure defining a trench space encompassing the reactor enclosure and defining a third thermally insulative region, the third thermally insulative region being held at a temperature that is cooler than the temperature of the second thermally insulative region.

A system comprising

• a first thermally insulative region defined about a plurality of molten fuel salt bearing components by an internal shield;
• a second thermally insulative region defined about the internal shield by a reactor enclosure, the second thermally insulative region being held at a temperature that is cooler than a temperature of the first thermally insulative region;
• and
• a third thermally insulative region defined about the reactor enclosure by a below-grade concrete structure, the third thermally insulative region being held at a temperature that is cooler than a temperature of the second thermally insulative region.

A method comprising

• maintaining a first thermally insulative region defined about a plurality of molten fuel salt bearing components by an internal shield;
• maintaining a second thermally insulative region defined about the internal shield by a reactor enclosure;
• and
• maintaining a third thermally insulative region defined about the reactor enclosure by a below-grade concrete structure.