Massive Pellet and Rupture Disk Testing for Disruption Mitigation Applications
By:
Combs, Stephen K; Meitner, Steven J; Baylor, Larry R; Caughman, John B; Commaux, Nicolas J; Fehling, Daniel T; Foust, Charles R; Jernigan, Thomas C; Mcgill, James M; Parks, P. B.; Rasmussen, David A
Page Number:
89-92
Publication Date:
May 2009
Conference Name:
23rd Symposium on Fusion Engineering
Conference Location:
San Diego, California, United States of America
Conference Sponsor:
IEEE/NPSS
Abstract
Injection of massive quantities of noble gases or D2 has proven to be effective at mitigating some of the deleterious effects of disruptions in tokamaks. Two alternative methods that might offer some advantages over the present technique for massive gas injection are “shattering” massive pellets and employing close-coupled rupture disks. Laboratory testing has been carried out to evaluate their feasibility. For the study of massive pellets, a pipe gun pellet injector cooled with a cryogenic refrigerator was fitted with a relatively large barrel (16.5 mm bore), and D2 and Ne pellets were made and were accelerated to speeds of ~600 and 300 m/s, respectively. Based on the successful proof-of-principle testing with the injector and a special double-impact target to shatter pellets, a similar system has been prepared and installed on DIII-D and should be ready for experiments later this year. To study the applicability of rupture disks for disruption mitigation, a simple test apparatus was assembled in the lab. Commercially available rupture disks of 1 in. nominal diameter were tested at conditions relevant for the application on tokamaks, including tests with Ar and He gases and rupture pressures of ~54 bar. Some technical and practical issues of implementing this technique on a tokamak are discussed.
