Experimental study of pellet delivery to the ITER inner wall through a curved guide tube at steady-state pressure

S. K. Combs, L. R. Baylor, J. B.O. Caughman, D. T. Fehling, C. R. Foust, S. Maruyama, J. M. McGill, D. A. Rasmussen

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Scopus citations

Abstract

Injection of solid hydrogen pellets from the magnetic high-field side will be the primary technique for depositing fuel particles into the core of International Thermonuclear Experimental Reactor (ITER) burning plasmas. This injection scheme will require the use of a curved guide tube to route the pellets from the acceleration device, under the divertor, and to the inside wall launch location. In an initial series of pellet tests in support of ITER, single 5.3-mm-diam cylindrical D2 pellets were shot through a mock-up of the planned ITER curved guide tube. Those data showed that the pellet speed had to be limited to ≈300 m/s for reliable delivery of intact pellets. Also, microwave cavity mass detectors located upstream and downstream of the test tube indicated that ≈10% of the pellet mass was lost in the guide tube at 300 m/s. The tube base pressure for that test series was ≈10-4 torr. However, for steady-state pellet fueling on ITER, the guide tube will operate at an elevated pressure due to the pellet erosion in the tube. Assuming the present design values for ITER pellet fueling rates/vacuum pumping and a 10% pellet mass loss during flight in the tube, calculations suggest a steadystate operating pressure in the range of 10-20 torr. Thus, experiments to ascertain the pellet integrity and mass loss under these conditions have been carried out. Also, some limited test data were collected at a tube pressure of ≈100 torr. No significant detrimental effects have been observed at the higher tube pressures. The new test results are presented and compared to the baseline data previously reported.

Original languageEnglish
Title of host publication21st IEEE/NPS Symposium on Fusion Engineering, SOFE'05
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Print)142440150X, 9781424401505
DOIs
StatePublished - 2005
Event21st IEEE/NPS Symposium on Fusion Engineering, SOFE'05 - Knoxville, TN, United States
Duration: Sep 26 2005Sep 29 2005

Publication series

NameProceedings - Symposium on Fusion Engineering

Conference

Conference21st IEEE/NPS Symposium on Fusion Engineering, SOFE'05
Country/TerritoryUnited States
CityKnoxville, TN
Period09/26/0509/29/05

Keywords

  • Curved guide tube
  • ITER
  • Inner wall
  • Pellet injection
  • Plasma

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