Phoebus (nuclear reactors)
Comparison of the KIWI and Phoebus assemblies.
Phoebus was a series of nuclear reactors, designed and built in the 1960s as part of the Rover program, to meet the needs of an interplanetary mission (see nuclear propulsion), in particular a manned mission to Mars. The design requirements were a thrust of 250,000 pounds, a specific impulse (Isp) of 840 second, and a reactor power level of 5,000 MWt.
The Phoebus-1 series was intended to study increasing the reactor power density and proved successful. When the power density was increased still further in the Phoebus-2 series, however, cooling of the aluminum pressure vessel was found to be a limiting factor. The Phoebus series demonstrated: 1) basic core and fuel configuration technology, 2) control of rocket parameters over a wide range of operating conditions, 3) the niobium carbide-molybdenum (NbC-Mo) coating could protect the fuel elements from hydrogen corrosion, 4) a two-pass regeneratively-cooled support structure allows full core performance, and 5) large nozzles for nuclear thermal rocket application were feasible. Other reactors developed during the Rover program were KIWI, Peewee-1, and Nuclear Furnace 1.
|Phoebus series summary|
|Phoebus-1A||Jun 25, 1965||1,090||630|
|Phoebus-1B||Feb 23, 1967||1,450||1,800|
|Phoebus-2A||Jun 26, 1968||4,082||750|
|Phoebus-2A performance parameters|
|reactor power (MWt)||4,082|
|flow rate (kg/s)||119.2|
|fuel exit temp (K)||2,283|
|chamber temp (K)||2,256|
|chamber pressure (MPa)||3.83|
|core inlet temp (K)||137|
|core inlet pressure (MPa)||4.73|
|reflector inlet temp (K)||68|
|reflector inlet pressure (MPa)||5.39|
|periphery & structural flow (kg/s)||2.3|