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; 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 fast reactor system of claim 1, wherein each of the plurality of heat pipes in the core block comprise:a sealed tube comprising volatile liquid that vaporizes into vapor when exposed to heat and condenses into condensate proximate to the active heat exchanger, the decay heat exchanger, or both, when cooled; anda wick that predominantly uses capillary forces to draw the condensate of the volatile liquid proximate to the active heat exchanger, the decay heat exchanger, or both, back toward the core block, whereina shape of the wick imposes order on the volatile liquid by forming menisci between the condensate and the vapor and allowing the condensate to flow toward the core block. 3. The mobile heat pipe cooled fast reactor system of claim 2, wherein the volatile liquid comprises potassium or sodium. 4. The mobile heat pipe cooled fast reactor system of claim 1, further comprising:a plurality of control drums and a reflector. 5. The mobile heat pipe cooled fast reactor system of claim 1, wherein there are more fuel pins than heat pipes. 6. The mobile heat pipe cooled fast reactor system of claim 5, wherein there are two fuel pins for every heat pipe. 7. The mobile heat pipe cooled fast reactor system of claim 1, further comprising:an Al2O3 reflector that surrounds the core block along an axis perpendicular to a circumference of the core block. 8. The mobile heat pipe cooled fast reactor system of claim 1, further comprising:a combustion engine; anda turbine configured to receive, and be driven by, a power conversion working fluid of the active heat exchanger heated by the mobile heat pipe cooled fast reactor and the combustion engine, whereinthe system is configured to drive the turbine via the mobile heat pipe cooled fast reactor when the mobile heat pipe cooled fast reactor is connected, and via the combustion engine when the mobile heat pipe cooled fast reactor is not connected. 9. The mobile heat pipe cooled fast reactor system of claim 8, wherein the turbine is configured to be driven by the power conversion working fluid heated by both the mobile heat pipe cooled fast reactor and the combustion engine. 10. The mobile heat pipe cooled fast reactor system of claim 1, further comprising:a lower active heat exchanger plenum located between the decay heat exchanger and the active heat exchanger; andan upper active heat exchanger plenum located on an opposite side of the active heat exchanger from the lower active heat exchanger. 11. The mobile heat pipe cooled fast reactor system of claim 1, wherein no parts of the decay heat exchanger and the active heat exchanger overlap along an axis in a direction running through a center of each of the heat pipes, but perpendicular to a circumference thereof.