Patent Number: 
Section: claims

1. An apparatus for removing thermal energy from a nuclear reactor, comprising: a heat pipe configured to absorb the thermal energy produced by the nuclear reactor;  a first compartment thermally coupled to said heat pipe;  first gas inlet and gas outlet ducts coupled to said first compartment;  a second compartment thermally coupled to said heat pipe; and  second gas inlet and gas outlet ducts coupled to said second compartment,  wherein said first compartment, said first gas inlet, and said first gas outlet are pneumatically isolated from said second compartment, said second gas inlet, and said second gas outlet. 2. The apparatus according to  claim 1 , further comprising: claim 1 a third compartment thermally coupled to said heat pipe; and  third gas inlet and gas outlet ducts coupled to said third compartment. 3. The apparatus according to  claim 2 , wherein said third compartment, said third gas inlet duct, and said third gas outlet duct are pneumatically isolated from said first compartment, said first gas inlet, and said first gas outlet. claim 2 4. The apparatus according to  claim 2 , wherein said third compartment, said third gas inlet duct, and said third gas outlet duct are pneumatically isolated from said first and second gas compartments, said first and second gas inlet ducts, and said first and second gas outlet ducts. claim 2 5. The apparatus according to  claim 2 , further comprising. claim 2 a fourth compartment thermally coupled to said heat pipe; and  fourth gas inlet and gas outlet ducts coupled to said fourth compartment. 6. The apparatus according to  claim 5 , wherein said fourth compartment, said fourth gas inlet duct, and said fourth gas outlet duct are pneumatically isolated from said first compartment, said first gas inlet, and said first gas outlet. claim 5 7. The apparatus according to  claim 5 , wherein said fourth compartment, said fourth gas inlet duct, and said fourth gas outlet duct are pneumatically isolated from said first, second, and third gas compartments, said first, second, and third gas inlet ducts, and said first, second, and third gas outlet ducts. claim 5 8. The apparatus according to  claim 5 , further comprising: claim 5 a fifth compartment thermally coupled to said heat pipe; and  fifth gas inlet and gas outlet ducts coupled to said fifth compartment. 9. The apparatus for removing thermal energy from the nuclear reactor of  claim 8 , wherein said first compartment, said fifth gas inlet duct, and said fifth gas outlet duct are pneumatically isolated from said first compartment, said first gas inlet, and said first gas outlet. claim 8 10. The apparatus for removing thermal energy from the nuclear reactor of  claim 5 , wherein said fifth compartment, said fifth gas inlet duct, and said fifth gas outlet duct are pneumatically isolated from said first, second, third, and fourth gas compartments, said first, second, third, and fourth gas inlet ducts, and said first, second, third, and fourth gas outlet ducts. claim 5 11. The apparatus for removing thermal energy from the nuclear reactor of  claim 1 , further comprising a plurality of heat pipes in addition to said heat pipe that are the coupled to said first compartment and said second compartment. claim 1 12. The apparatus for removing thermal energy from the nuclear reactor of  claim 8 , further comprising a plurality of heat pipes in addition to said heat pipe that are thermal coupled to said first compartment, said second compartment, said third compartment, said fourth compartment and said fifth compartment. claim 8 13. The apparatus for removing thermal energy from the nuclear reactor of  claim 1 , said heat pipe comprising: claim 1 an inner pipe enclosing nuclear fuel of the nuclear reactor;  an outer pipe enclosing the inner pipe; and  a space interposed between said inner pipe and said outer pipe. 14. The apparatus for removing thermal energy from the nuclear reactor of  claim 13 , wherein said space is a vapor space that is configured to contain a fluid. claim 13 15. The apparatus for removing thermal energy from the nuclear reactor of  claim 13 , wherein said outer pipe has first protusion extending into said first compartment. claim 13 16. The apparatus for removing thermal energy from the nuclear reactor of  claim 15 , further comprising a second protrusion extending into said second compartment. claim 15 17. A vehicle, comprising: a nuclear reactor;  an apparatus for removing thermal energy from said nuclear reactor, said apparatus comprising:  a heat pipe configured to absorb thermal energy produced by the nuclear reactor;  a first compartment thermally coupled to said heat pipe;  first gas inlet and gas outlet ducts coupled to said first compartment;  a second compartment thermally coupled to said heat pipe; and  second gas inlet and gas outlet ducts coupled to said second compartment, wherein said first compartment, said first gas inlet, and said first gas outlet are pneumatically isolated from said second compartment, said second gas inlet, and said second gas outlet; and  an energy conversion system configured to convert at least a portion of said thermal energy removed from said nuclear reactor by said apparus into power for the vehicle. 18. The vehicle of  claim 17 , wherein said vehicle is a spacecraft. claim 17 19. The vehicle of  claim 17 , wherein said energy conversion system is configured to implement a Brayton energy conversion cycle for conversion of said portion of said thermal energy removed from said nuclear reactor by said apparatus into power for the vehicle. claim 17