Radial flow nuclear thermal rocket (RFNTR)

Abstract

A radial flow nuclear thermal rocket fuel assembly includes a substantially conical fuel element having an inlet side and an outlet side. An annular channel is disposed in the element for receiving a nuclear propellant, and a second, conical, channel is disposed in the element for discharging the propellant. The first channel is located radially outward from the second channel, and separated from the second channel by an annular fuel bed volume. This fuel bed volume can include a packed bed of loose fuel beads confined by a cold porous inlet frit and a hot porous exit frit. The loose fuel beads include ZrC coated ZrC-UC beads. In this manner, nuclear propellant enters the fuel assembly axially into the first channel at the inlet side of the element, flows axially across the fuel bed volume, and is discharged from the assembly by flowing radially outward from the second channel at the outlet side of the element.

The embodiments of the invention in which exclusive property rights or privileges are claimed are defined as follows: 
     
       1. A radial flow nuclear thermal rocket fuel assembly comprising: a) a substantially conical fuel element having an inlet side and an outlet side;   b) a first annular channel disposed in the element for receiving a nuclear propellant;   c) a second channel disposed in the element for discharging the nuclear propellant, the annular channel being located radially outward from the second channel, and separated from the second channel by an annular fuel bed volume; whereby the propellant enters the fuel assembly axially into the first channel at the inlet side of the element, flows axially across the fuel bed volume, and is discharged from the assembly by flowing radially outward from the second channel at the outlet side of the element.     
     
     
       2. The fuel assembly of claim 1 wherein the fuel bed volume includes a packed bed of loose fuel beads confined by a cold porous inlet frit and a hot porous exit frit. 
     
     
       3. The fuel assembly of claim 2 wherein the fuel beads include ZrC coated ZrC-UC beads. 
     
     
       4. A radial flow nuclear thermal rocket comprising: a) a shell-type reactor having a thrust chamber including a propellant inlet, reactor core, and a nozzle connected to the thrust chamber,   b) a plurality of substantially conical fuel assemblies each having an inlet side and an outlet side, the inlet side being adjacent to the propellant inlet, and the outlet side being adjacent to the thrust chamber,   c) each fuel assembly including a first axial channel for receiving a propellant, a second axial channel for discharging the propellant, the first channel being located radially outward from the second channel, and separated from the second channel by an annular fuel bed volume;   d) the fuel assemblies lying in a radial pattern in the reactor core, and each assembly being separated by a moderator, whereby propellant flows into the propellant inlet, and enters each fuel assembly axially into the first channel at the inlet side of the element, flows axially across the fuel bed volume, and is discharged from the assembly by flowing radially outward from the second channel at the outlet side of the element into the thrust chamber and into the nozzle.     
     
     
       5. The fuel assembly of claim 4 wherein the fuel bed volume includes a packed bed of loose fuel beads confined by a cold porous inlet frit and a hot porous exit frit. 
     
     
       6. The fuel assembly of claim 5 wherein the fuel beads include ZrC coated ZrC-UC beads.