Solid conveyance with single phase change method for cryogenic extrusion recirculation
A cryogenic extrusion recirculation system and method are provided. In one embodiment, the system includes a cryogenically-cooled extruder configured to form solid deuterium-tritium pellets and discharge the pellets through an extruder nozzle. Excess solid extrusion discharged from the extruder nozzle is received by a cryogenically-cooled auger, which conveys the excess material into a restrictive section. The excess material consolidates in the restrictive section as a solid fuel plug. A heater section is positioned downstream of the restrictive section and applies energy to the leading portion of the solid fuel plug, converting the leading portion of the solid fuel plug into a gaseous phase. This gaseous phase is then recirculated into the cryogenically-cooled extruder to support continuous pellet formation in a controlled and efficient manner. Other embodiments include one or more cryopumps in lieu of the cryogenically-cooled auger for converting the excess material into a gaseous phase for recirculation.
1 . A cryogenic extrusion recirculation system comprising:
a cryogenically-cooled extruder configured to form a solid deuterium-tritium (D-T) ribbon and discharge the solid D-T ribbon through an extruder nozzle;
a pellet cutter configured to separate the solid D-T ribbon into a plurality of D-T pellets for output to a pellet gun barrel;
a cryogenically-cooled augur that is positioned to receive excess solid extrusion from the pellet cutter;
a restrictive section disposed downstream of the cryogenically-cooled augur, the restrictive section being configured to receive the excess solid extrusion from the cryogenically-cooled augur as a solid fuel plug;
a heater section positioned downstream of the restrictive section and configured to heat a leading portion of the solid fuel plug and thereby convert the leading portion of the solid fuel plug into a gaseous phase; and
wherein the gaseous phase is recirculated to the cryogenically-cooled extruder for continuous D-T pellet formation.
2 . The system of claim 1 , wherein the heater section comprises at least one of a resistive heating element, an inductive heater, or a laser heat source.
3 . The system of claim 1 , wherein the heater section is configured to control heating of the solid fuel plug such that the recirculated gaseous phase includes a pressure that matches an inlet pressure of the cryogenically-cooled extruder.
4 . The system of claim 1 , wherein the gaseous phase is heated to between 20 K and 80 K by the heater section.
5 . The system of claim 1 , wherein the restriction section is disposed between the cryogenically-cooled auger and the heater section.
6 . The system of claim 1 , wherein the gaseous phase is introduced into a supply line downstream of a pre-cooler and upstream of the cryogenically-cooled extruder.
7 . The system of claim 1 , wherein the cryogenically-cooled augur conveys excess solid extrusion perpendicularly away from the extruder nozzle.
8 . The system of claim 1 , wherein the restrictive section is disposed along an axis that is substantially perpendicular to an extrusion axis of the extruder nozzle.
9 . The system of claim 1 , wherein the cryogenically-cooled auger is magnetically coupled to a motor disposed outside of a cryostat housing.
10 . The system of claim 1 , wherein the cryogenically-cooled extruder includes a cryogenic jacket extending around an extruder barrel.