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Title: Twin-Screw Extruder Development for the ITER Pellet Injection System

Abstract

The ITER pellet injection system is comprised of devices to form and accelerate pellets, and will be connected to inner wall guide tubes for fueling, and outer wall guide tubes for ELM pacing. An extruder will provide a stream of solid hydrogen isotopes to a secondary section, where pellets are cut and accelerated with a gas gun into the plasma. The ITER pellet injection system is required to provide a plasma fueling rate of 120 Pa-m3/s (900 mbar-L/s) and durations of up to 3000 s. The fueling pellets will be injected at a rate up to 10 Hz and pellets used to trigger ELMs will be injected at higher rates up to 20 Hz. A twin-screw extruder for the ITER pellet injection system is under development at the Oak Ridge National Laboratory. A one-fifth ITER scale prototype has been built and has demonstrated the production of a continuous solid deuterium extrusion. The 27 mm diameter, intermeshed, counter-rotating extruder screws are rotated at a rate up to ≈5 rpm. Deuterium gas is pre-cooled and liquefied and solidified in separate extruder barrels. The precooler consists of a deuterium gas filled copper coil suspended in a separate stainless steel vessel containing liquid nitrogen.more » The liquefier is comprised of a copper barrel connected to a Cryomech AL330 cryocooler, which has a machined helical groove surrounded by a copper jacket, through which the pre-cooled deuterium condenses. The lower extruder barrel is connected to a Cryomech GB-37 cryocooler to solidify the deuterium (at ≈15 K) before it is forced through the extruder die. The die forms the extrusion to a 3 mm x 4 mm rectangular cross section. Design improvements have been made to improve the pre-cooler and liquefier heat exchangers, to limit the loss of extrusion through gaps in the screws. This paper will describe the design improvements for the next iteration of the extruder prototype.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [2]
  1. ORNL
  2. University of Wisconsin, Madison
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); ITER Organization, St. Paul Lez Durance (France)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1056885
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: 23rd Symposium on Fusion Energy, San Diego, CA, USA, 20090531, 20090605
Country of Publication:
United States
Language:
English

Citation Formats

Meitner, Steven J, Baylor, Larry R, Combs, Stephen Kirk, Fehling, Dan T, McGill, James M, Rasmussen, David A, and Leachman, J. W. Twin-Screw Extruder Development for the ITER Pellet Injection System. United States: N. p., 2009. Web.
Meitner, Steven J, Baylor, Larry R, Combs, Stephen Kirk, Fehling, Dan T, McGill, James M, Rasmussen, David A, & Leachman, J. W. Twin-Screw Extruder Development for the ITER Pellet Injection System. United States.
Meitner, Steven J, Baylor, Larry R, Combs, Stephen Kirk, Fehling, Dan T, McGill, James M, Rasmussen, David A, and Leachman, J. W. 2009. "Twin-Screw Extruder Development for the ITER Pellet Injection System". United States.
@article{osti_1056885,
title = {Twin-Screw Extruder Development for the ITER Pellet Injection System},
author = {Meitner, Steven J and Baylor, Larry R and Combs, Stephen Kirk and Fehling, Dan T and McGill, James M and Rasmussen, David A and Leachman, J. W.},
abstractNote = {The ITER pellet injection system is comprised of devices to form and accelerate pellets, and will be connected to inner wall guide tubes for fueling, and outer wall guide tubes for ELM pacing. An extruder will provide a stream of solid hydrogen isotopes to a secondary section, where pellets are cut and accelerated with a gas gun into the plasma. The ITER pellet injection system is required to provide a plasma fueling rate of 120 Pa-m3/s (900 mbar-L/s) and durations of up to 3000 s. The fueling pellets will be injected at a rate up to 10 Hz and pellets used to trigger ELMs will be injected at higher rates up to 20 Hz. A twin-screw extruder for the ITER pellet injection system is under development at the Oak Ridge National Laboratory. A one-fifth ITER scale prototype has been built and has demonstrated the production of a continuous solid deuterium extrusion. The 27 mm diameter, intermeshed, counter-rotating extruder screws are rotated at a rate up to ≈5 rpm. Deuterium gas is pre-cooled and liquefied and solidified in separate extruder barrels. The precooler consists of a deuterium gas filled copper coil suspended in a separate stainless steel vessel containing liquid nitrogen. The liquefier is comprised of a copper barrel connected to a Cryomech AL330 cryocooler, which has a machined helical groove surrounded by a copper jacket, through which the pre-cooled deuterium condenses. The lower extruder barrel is connected to a Cryomech GB-37 cryocooler to solidify the deuterium (at ≈15 K) before it is forced through the extruder die. The die forms the extrusion to a 3 mm x 4 mm rectangular cross section. Design improvements have been made to improve the pre-cooler and liquefier heat exchangers, to limit the loss of extrusion through gaps in the screws. This paper will describe the design improvements for the next iteration of the extruder prototype.},
doi = {},
url = {https://www.osti.gov/biblio/1056885}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 2009},
month = {Thu Jan 01 00:00:00 EST 2009}
}

Conference:
Other availability
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