Patent Number: 
Section: claims

1. A mobile heat pipe cooled reactor system, comprising:a core block;a plurality of heat pipes comprising coolant, a portion of each of the plurality of heat pipes extending into the core block and another portion of each of the plurality of heat pipes extending outward from the core block;a plurality of fuel pins containing nuclear fuel, the plurality of fuel pins located within the core block and positioned proximate to the portions of the plurality of heat pipes extending into the core block;a decay heat exchanger located outside the core block and surrounding part of the portion of each of the plurality of heat pipes extending outward from the core block, the decay heat exchanger configured to perform decay heat removal;shielding located between the decay heat exchanger and the core block; andan active heat exchanger outside the core block and surrounding another part of the portion of each of the plurality of heat pipes extending outward from the core block, whereinthe plurality of heat pipes are operably connected to the core block, the decay heat exchanger and the active heat exchanger,the plurality of heat pipes are configured to transfer heat away from the core block to an outside of the reactor system through the active heat exchanger, the decay heat exchanger, or both, andthe decay heat exchanger is located closer to the core block than the active heat exchanger. 2. The mobile heat pipe cooled reactor system of claim 1, further comprising:a gas plenum located between the decay heat exchanger and the core block. 3. The mobile heat pipe cooled reactor system of claim 2, further comprising:a reflector located between the gas plenum and the core block. 4. The mobile heat pipe cooled reactor system of claim 3, further comprising:a lower plenum located between the decay heat exchanger and the active heat exchanger. 5. The mobile heat pipe cooled reactor system of claim 4, further comprising:an upper plenum, whereinthe active heat exchanger is located between the upper plenum and the lower plenum. 6. The mobile heat pipe cooled reactor system of claim 1, wherein the core block comprises a plurality of segments. 7. The mobile heat pipe cooled reactor system of claim 6, wherein the segments of the plurality of segments are mechanically and thermally isolated from each other. 8. The mobile heat pipe cooled reactor system of claim 7, wherein the segments of the plurality of segments are neutronically connected to each other. 9. A reactor system, comprising:a core block;a plurality of heat pipes, a portion of each of the plurality of heat pipes extending into the core block and another portion of each of the plurality of heat pipes extending outward from the core block;a plurality of fuel pins containing nuclear fuel, the plurality of fuel pins located within the core block and positioned proximate to the portions of the plurality of heat pipes extending into the core block;a decay heat exchanger located outside the core block and surrounding part of the portion of each of the plurality of heat pipes extending outward from the core block, the decay heat exchanger configured to perform decay heat removal; andan active heat exchanger located outside the core block and surrounding another part of the portion of each of the plurality of heat pipes extending outward from the core block, whereinthe decay heat exchanger is located closer to the core block than the active heat exchanger. 10. The reactor system of claim 9, further comprising:a gap between the decay heat exchanger and the core block. 11. The reactor system of claim 9, further comprising:shielding located between the decay heat exchanger and the core block. 12. The reactor system of claim 9, further comprising:a gap between the decay heat exchanger and the active heat exchanger. 13. The reactor system of claim 9, wherein the core block comprises a plurality of segments. 14. The reactor system of claim 13, wherein the segments of the plurality of segments are mechanically isolated from each other. 15. The reactor system of claim 14, wherein the segments of the plurality of segments are thermally isolated from each other. 16. The reactor system of claim 15, wherein the segments of the plurality of segments are neutronically connected to each other. 17. A reactor system, comprising:a core block;a plurality of heat pipes, a portion of each of the plurality of heat pipes extending into the core block and another portion of each of the plurality of heat pipes extending outward from the core block;a decay heat exchanger located outside the core block and surrounding part of the portion of each of the plurality of heat pipes extending outward from the core block, the decay heat exchanger configured to perform decay heat removal; andan active heat exchanger located outside the core block and surrounding another part of the portion of each of the plurality of heat pipes extending outward from the core block, whereinthe decay heat exchanger is located closer to the core block than the active heat exchanger. 18. The reactor system of claim 17, further comprising:a gap between the decay heat exchanger and the core block. 19. The reactor system of claim 17, further comprising:shielding located between the decay heat exchanger and the core block. 20. The reactor system of claim 17, further comprising:a reflector located between the decay heat exchanger and the core block.